Docstoc

Communication_Engineering

Document Sample
Communication_Engineering Powered By Docstoc
					                  Department of Communication Engineering

Title:Medium Access Control and Call Admission Control for WCDMA Systems
Principal Investigator:Chung-Ju Chang
Sponsor:National Science Council
Keywords:WCDMA, Third Generation System, Medium Access Control, Call
                Admission Control, Power Control, Code Allocation, Resource
                Management, Fuzzy Logic, Neural Network
       In 3G systems, wideband technology for providing various services and higher
system capacity are most important issues. In order to provide different types of
services in the same infrastructure, the wideband technologies must simultaneously
integrate delay sensitive services, loss sensitive services, and multimedia services,
and guarantee the required QoS for each type of services.
       WCDMA technology is more suitable for smooth traffic applications. However,
it is not suitable for applications with more burstness because all transmitted packets
using the same carrier will be lost due to too large instantaneous multiple access
interference (MAI). This problem is even worse in the uplink. In order to satisfy the
requirements of 3G systems, in this project we will design more flexible and more
efficient uplink MAC control to support various types of services and guarantee their
QoSs. To do this, we are going to input data, output from rake receiver, or in the later
output from multiuser detector, into SIR estimator to determine the users which can
request resource in the next frame.
      Besides, in order to provide variable rate services, multirate transmission
capability is necessary. Many multi-code and single code with variable spreading
factor schemes were proposed. In WCDMA systems, an orthogonal variable
spreading factor code was proposed in ETSI UTRA. In this project, we will design an
appropriate channel code allocation scheme for users with corresponding transmission
rate to enhance the efficiency of the channel code utilization. Furthermore, we will
design a proper power control scheme to achieve good performance for the 3G
WCDMA systems.
      On the other hand, although good MAC control can achieve better system
performance, conditioning on the active users number, MAC control will still be out
of control as too many users in the systems. Therefore, we have to limit the
reasonable number of users in the system based on call admission control. In the
project, a sophisticated call admission control mechanism will be designed so that the
required QoSs of the new call and the existing calls will be satisfied and guaranteed.
NSC89-2219-E009-014 (89N018)
-------------------------------------------------------------------------------------------------------
Title:Traffic Management and Signaling System for ATM Networks
Principal Investigator:Ching-Ju Chang
Sponsor:National Science Council
Keywords:ATM, Traffic Control, Signaling, Admission Control, Flow Control


     There are many research topics in high-speed networks providing multimedia
information services. In ATM networks, traffic control and management and signaling
system are two issues not being solved and still being studied and developed. This
project takes three years to analyze and design the traffic control and management
schemes for all kinds of CBR, VBR, and ABR services; and the schemes will finally
be implemented into VLSI chips to satisfy the real-time requirement and fulfill the
realization purpose. In the mean time, the study on signaling system, necessary for
carrying these traffic control and management messages between customer premise
equipments and node (or UNI), is also included. Thus, the first subproject will design
and analyze the traffic control for VBR services, using neural-net and/or fuzzy logic
techniques from time-domain or frequency-domain points of view.
     The second subproject will study and design the signaling system using
object-oriented design, where the features of the signaling system include
point-to-point cases, point-to-multipoint, virtual path services, etc. The study and
development or signaling system will develop Service Specific Connection Oriented
Protocol (SSCOP), Q.2931, and Q.2971 based on AAL5 SAAL (Signaling ATM
Adapatation Layer). The third subproject is to develop and analyze universal flow
control schemes to effectively predict and control QoS demanded by heterogeneous
CBR applications. The fourth subproject is to propose a viable flow control algorithm.
Moreover, it will examine and analyze the strengths and weaknesses of current
existing promising source traffic models (MMBP, MMPP, MMFP, Self-similar traffic
modeling) and offer appropriate analysis based on the selected models for ABR traffic
management.
NSC89-2213-E009-104 (89N326)
-------------------------------------------------------------------------------------------------------

Title:Design and Implementation of VBR Traffic Controllers for ATM Networks
Principal Investigator:Chung-Ju Chang
Sponsor:National Science Council
Keywords:ATM LAN, Fuzzy Logic Controller, Neural Fuzzy Controller, Call
         Admission Control, Congestion Control, Resource Management,
         Usage Parameters Control
      In this project, we intend to design a traffic control algorithm based on the
trend of VBR traffic source modeling and ATM related specifications.
      In the first year, we had proposed proper traffic source models (VBR source
model for voice and video, and self-similar model for data transmission). Based on
the proposed model and proper time-domain parameters, we had designed connection
admission control algorithm (rate-based feedback congestion control, queue length
threshold resource management, and buffer management algorithm are all included)
and usage parameter control (leaky bucket control) methods. A fuzzy or neural
implementation of the proposed traffic control algorithm had also been introduced.
      In the second year, we will study important issues of traffic control mechanism
specified in ITU-T Recommendation I.371 and ATM Forum UNI 4.0 from the
viewpoint of power spectrum. Proper traffic source models (VBR source model for
voice and video, and self-similar model for data transmission) will also be proposed
based on the parameters of power spectrum of input processes. Based on the proposed
model, we will design power-spectrum-based connection admission control algorithm
(rate-based feedback congestion control, queue length threshold resource
management, and buffer management algorithm are all included) and
power-spectrum-based usage parameter control (leaky bucket control) methods. A
fuzzy or neural implementation of the proposed power-spectrum-based traffic control
algorithm is also introduced. By now, we have finished some research about the
power spectrum of a given traffic source, and have designed the corresponding
power-spectrum-domain-based connection admission control (PSD-CAC) algorithm
so far.
      In this (last) year, we will give a fine tune of the proposed time-based and
power-spectrum-based fuzzy traffic control algorithm, and the performance of these
algorithms will be evaluated. Also , fuzzy logic and/or neural-net chips will be used to
implement a better one from these proposed fuzzy traffic control algorithms, and
hopefully, they can be used as control engines. Furthermore, we will integrate the
proposed software modules and hardware structures with other modules of the ATM
network to accomplish the integration test. This project provides a chance to apply the
proposed fuzzy traffic control modules and their fuzzy logic chips implementation to
develop a prototype of an ATM system, and the validity of the control algorithms
could also be verified.
NSC89-2213-E009-105 (89N327)
-------------------------------------------------------------------------------------------------------

Title:Variable Bit Rate Video Transmission with Discrete Multi-Tone Multiplex
Principal Investigator:Chung-Ju Chang
Sponsor:ITRT
Keywords:TDMA, CDMA, Access Control, Dynamic Channel Assignment, QoS,
                Spectrum Efficiency


     Power control mechanism is an important method to control communication
quality for every wireless communication system. However, in wideband CDMA
(code division multiple access), there exist the characteristic of cross-interference
between customers’ signal and multipath fading so performance of a power control
mechanism will affect whole communication quality and system capacity. Generally,
power control is an important problem for a wideband CDMA system. In the past
studies, we have investigated the performance of strength-based and SIR-based power
control mechanisms for CDMA cellular mobile communication systems. These two
ethods can provide good communication quality for voice communication and arger
system capacity. In this project, we intend to study a suitable ultimedia power control
mechanism for third generation PCS (personal ommunication services). We will study
the key factor—interference of CDMA ystem and globally collect relative literatures
to design the multimedia power control mechanism. We hope that the power control
method can provide better communication quality and higher system capacity by
reducing system interference.
C89070 (88.08.01-89.07.31)
-------------------------------------------------------------------------------------------------------

Title:New MM-Wave Uniplanar RF Receiver and Sources
Principal Investigator:Chi-Yang Chang
Sponsor:National Science Council
Keywords:MM-Wave Receiver, MM-Wave Oscillator, Uniplanar Circuit


      This project will be finished in 3 years.
      Recently, the frequency of microwave and millimeter wave circuit goes higher
and higher. Therefore, the uniplanar circuit becomes more and more important. The
advantages of uniplanar circuit such as no via hole or wrap around processes, low
parasitics, easy to make transition from one kind of transmission line to other kind of
planar transmission line.        For example, the transitions between coplanar
waveguide(CPW) and coplanar strips(CPS), CPW and slot line, CPW and microstrip
line, are easy to built.
       First year, a Ka band millimeter wave receiver will be made which includes RF
section and IF section.. The RF section comprises a uniplanar low noise amplifier, a
uniplanar mixer. IF section comprises an IF amplifier, qnd IF filter.
      This receiver will be connected to a feeding structure of a leaky wave antenna
which is developed by subprogram 1 and 3. Since the structure of the antenna feed,
the uniplanar circuit is most suitable to make interconnection with it.
      In the second year of this program, a mm-wave uniplanar VCO will be designed
and fabricated. This VCO will be used as local oscillator of the mm-wave receiver,
and as the source of the transmitting antenna. This VCO will use either frequency
doubler approach or direct oscillating in the mm-wave frequency.
       The third year will perform power amplifier design and fabrication. This is a
very important part of the whole system. A 13dBm of LO power for both transmitter
and receiver are required. Besides, the signal after up conversion is also need to be
amplified to a certain power level to feed the antenna. Therefore, the observing
range of the active imaging system could be increased.
NSC89-2213-E009-072 (89N481)
-------------------------------------------------------------------------------------------------------

Title:Design of Miniaturized Filter for Wideband Wireless Communication(II)
Principal Investigator:Chi-Yang Chang
Sponsor:Chung-Shan Institude of Science and Technology
Keywords:Filter, Miniaturized Filter, Cross-Coupled Filter, Trisection Filter,
               Cascaded Quardraplet Filter


        Recently the efforts to minimize the filter can be summarized in two categories.
The first one is to reduce the size of the resonators, and therefore reduce the size of
filter. In wideband wireless communication 5~6 GHz application, we have some
excellent results using this technique. The second one is change the filter frequency
response from conventional Chebyshev response to generalized Chebyshev or
elliptical function response. By using generalized Chebyshev or elliptical function
response. By using the wanted stop band response. In this project, we propose a
so-called cross coupled filter structure to realize these types of filters By introducing
cross coupling between non-adjacent resonators, the filter will show finite frequency
transmission zeros (conventional Chebyshev response the transmission zero is
occurred at zero and infinity frequency, or). The position of this finite frequency
transmission zero can be moved on the frequency axis by varying the coupling
coefficient of the cross coupling. Therefore, the filter can use fewer resonators than
that of conventional filter to achieve some stopband rejection, and of course the size
of the filter is reduced. In this program, we choose tri-section or CQ structure to
realized the filter. They show asymmetrical or symmetrical finite frequency
transmission zeros respectively. The detail design procedure and theory will be
developed and some prototype circuits will be fabricated also to verify the validity of
the theory.
I89022 (88.01.31-89.11.31)
-------------------------------------------------------------------------------------------------------

Title:Design of Ultra-Broadband Microwave Receiver Keycomponents
Principal Investigator:Chi-Yang Chang
Sponsor:Chung-Shan Institude of Science and Technology

Keywords:Image Rejection Mixer, Ultra-Broadband Mixer


       The purpose of this program is to develop an MIC ultra-broadband image
rejection mixer. The mixer should cover 2~18GHz microwave band. By using this
image rejection mixer, the interference signal rejection of a broadband microwave
receiver may therefore be improved.
      There are two major difficult portions of the proposed mixer. The first one is

90o and 0o       3dB couplers, and the second one is high isolation MIC ultra-broadband


mixer. The 90o ultra-broadband coupler should use multi-section structure to cover


2~18GHz bandwidth. However, the center section of this multi-section 90o coupler is

extremely difficult for the very high Z oe and very low Z oo values. This is a

challenge for MIC realization. All of the problems should be solved by this project.

       After all of the sub-circuit being developed and tested, they will be combined

to build a proposed mixer. The circuit will be developed using uniplanar circuit
structure because that it’s broadband performance is better than that of microstrip
circuit.

       The substrate used in this project is mainly Al2 O3 ceramic substrate.

I89016 (88.07.01-89.06.30)
-------------------------------------------------------------------------------------------------------

Title:Wireless Error-Resilient Secure Image Communications Via Wideband CDMA
         Channels
Principal Investigator:Po-Rong Chang
Sponsor:National Science Council
Keywords : Wideband CDMA, Error-Resilient Image Encryption, 2D Chaotic
              Random Codes


      Recently, standardization of third-generation mobile communication systems is
rapidly processing in all major regions of the world. These systems, called
International Mobile Telecommunications -2000 (IMT-2000) in the International
Telecommunication Union (ITU) are designed to support a wide variety of
multimedia services with diverse statistical characteristics and quality of service
(QOS) requirements at cell and call levels. To realize IMT-2000 systems, a new
wideband wireless access technology incorporating as many recent technology
developments as possible is necessary. The most promising candidate, wideband
CDMA(WCDMA), is being developed throughout the world.
     Unfortunately, wireless network are known for their susceptibility to tampering
and eavesdropping. In a wire network, the fact that a user must be physically
connected to the network, and that information is transmitted within protected
physical links(wires), offers some measure of security. However, in a wireless
network, there are no such quarantees as anyone with a simple radio transmitter can
pretend to be a valid network user. In addition, the transmission medium is the open
air which implies that anyone with the appropriate radio scanner can eavesdrop as
well. This project is aimed at developing a new cryptographic method for encrypting
the still JPEG images which are the important component of wireless multimedia
communications, and then provides the secure transmission of image information via
wireless WCDMA networks. Meanwhile, since the encryption process is highly
nonlinear, both the multipath fading and multi-user interference on WCDMA radio
channels tend to cause significant transmission error, and the encrypted JPEG images
are very vulnerable to these errors. To tackle this difficulty, an adaptive channel
optimized scalar quantizer is developed for encoding memoryless
Gaussion-distributed source signals and transmission over the WCDMA channel
according to the value of signal-to-interference ratio(SIR).The prediction value of SIR
on the WCDMA channel can be obtained by pipelined recurrent neural networks with
real-time capacity.
       In addition, an all-pass filtering is proposed to convert the input JPEG images
with arbitrary marginal probability distribution function to the memoryless
Gaussian-distributed source signals. A way to realize the all-pass filtering is to
scramble the phase spectra of the input JPEG image by adding some randomized
reference phase spectra as prefiltering, and then subtracting the same reference phase
spectra as postfiltering, to recover the original phase spectra of the image.From a
security standpoint, a new 2D chaotic signals which behave like purely random codes
were proposed to provide the randomized reference phase spectra for the all-pass
filtering whereas the well-known m-sequences and Gold codes provide limited
security as they can identified with a number of samples which is much less than their
actual length by means of linear regression models. Moreover, an error-resilient
entropy coding is introduced to combat catastrophic loss in the received image due to
burst and random errors.
       Finally, our error-resilient entropytion mechanism is also designed for the
application to a combination of wavelet multi-resolution coding and current JPEG
standard which will be the key technology for the forthcoming still image
compression standard JPEG-2000 in year 2000.
NSC89-2213-E009-085 (89N308)
-------------------------------------------------------------------------------------------------------

Title:Narrowband Interference Suppression in SS-CDMA Communications Using
       Pipelined Recurrent Neural Networks
Principal Investigator:Po-Rong Chang
Sponsor:National Science Council
Keywords:SS-CDMA, Narrowband Interference Suppression, Pipelined Recurrent
               Neural Networks


      This project investigates the application of pipelined recurrent neural
networks(PRNN) to the narrowband interference(NBI) suppression over spread
spectrum CDMA channels in the presence of multipath fading plus non-Gaussian
observation noise. Optimal detectors and receivers for recurrent neural network
(RNN) modules with less computational complexity is conducted to introduce best
nonlinear approximation capability into the minimum mean square error nonlinear
predictor model in order to accurately predict the NBI signal based on the adaptive
learning for each module from previous non-Gaussian observations. Once the
prediction of the NBI signal is obtained, a resulting signal is computed by subtracting
the estimate from the received signal. Thus the effect of the NBI can be reduced.
Moreover, since those modules of PRNN can be performed simultaneously in a
pipelined parallelism fashion, this would lead to a significant improvement in its total
computational efficiency. PRNN-based NBI rejection is able to provide a superior
SNR improvement relative to the conventional adaptive nonlinear ACM filters,
especially when the channel statistics and the exact number of CDMA users are not
known to those receivers. Finally an ALTERA FLEX 10K FPGA chip realization is
designed for the proposed PRNN-based NBI suppression to verify its effectiveness in
the real wireless CDMA communication testbed.
NSC89-2213-E009-087 (89N310)
-------------------------------------------------------------------------------------------------------

Title:Variable Bit Rate Video Transmission with Discrete Multi-Tone Multiplex
Principal Investigator:Wen-Thong Chang
Sponsor:National Science Council
Keywords:Discrete Multi-Tone, Orthogonal Frequency Division, Wavelet Filter
               Bank


       In video transmission, for the purpose of multiple access, a common channel is
partitioned into many sub-channels with different frequency bandwidth. This is one
kind of bandwidth-on-demand application. Under this condition, each user requests
certain bandwidth from the channel administrator. Thus, the partition of the
bandwidth must be flexible and adaptable, such that it can be changed easily
according to the number of users and the amount each user requests.
      To meet this kind of application, the use of discrete multi-tone for bandwidth
partition is proposed. Basically, the channel is partitioned into many unit-channel of
fixed bandwidth such as 64khz. Each user then request a sub-channel of bandwidth Pi

×64K composed of several unit-channels, where Pi is the request amount of the i-th

user .
    In this situation, each unit-channel of 64khz can be seen as an independent unit.
To combine these independent units into a sub-channel such that a common
modulation carrier can be used to transmit these combined unit-channels, discrete
multi-tone (DMT) is proposed as the modulation scheme to combine the unit-channels
into a sub-channel.
      For such an application, a signaling waveform has to be designed such that these
unit-channels can be combined without causing inter-unit-channel interference. In the
present application, a rectangular waveform modulated with either a cosine wave or a
sine wave is used. However, the bandwidth of a rectangular waveform is very wide
such that bandwidth overlap is very severe. In the case of channel fading,
inter-unit-channel interference is very significant. Therefore, to design a waveform
such that the inter-unit-channel interference can be reduced without sacrificing the
transmission rate is proposed in this project. The system that employs a waveform
rather than a rectangular pulse is called discrete wavelet multi-tone (DWMT)
      This condition is very similar to the design of the filter for a perfect
reconstruction filter bank. Therefore, many design concepts are similar. One of the
major differences is that, in DWMT, due to the choice of the modulation scheme,
there is more flexibility in the design of waveform modulation vector. Cosine
modulation filter bank is a commonly used filter bank. While, in present OFDM
system, QAM modulation is more popular. This implies the use of both the cosine
wave and the sine wave as the modulation vector in the filter bank design.
     Since a rectangular signaling waveform is used in the present DMT
implementation, FFT transform pair is used. To overcome the problem of channel
fading and noise, some researchers seek other orthogonal transforms as alternatives of
the FFT to combat noise to reduce the bit error rate. Many orthogonal transforms are
based on the design of new signaling waveform.
      Thus, from the point of view of orthogonal transform, our goal is similar to the
design of lapped orthogonal transform. The size of the transform is affected by two
factors. The first one is the span of the waveform (FFT can be seen as a rectangular
pulse of span =1). This is a measure of time dependence of the transmitted waveform
and is also an indication of the degree of bandwidth localization. The other factor is
the number of unit-channels to be combined. This is decided by the transmission
bandwidth requested. Thus, based on the transmission bandwidth required and the
degree of bandwidth localization, a set of waveforms is to be designed for use in the
DWMT system with QAM as the modulation scheme to provide variable bit rate
video transmission.
NSC89-2213-E009-133 (89N336)
-------------------------------------------------------------------------------------------------------

Title:Voiced-Mail System for Blind Users
Principal Investigator:Wen-Whei Chang
Sponsor:National Science Council
keywords:Blind Users, Voiced Mail, Sinusoidal Transform Coding, Time-Scale
               Modification


      This project is aimed to develop a voiced mail system that uses touch tones as
input and synthetic speech as output to provide blind user's access to electronic mails.
Our system will incorporate a low-rate speech coder that compresses blind user's
voiced messages in reply to the e-mail. Moreover, time-scale modification will be
used in message playback to maintain the perceptual quality of speech while changing
the rate of articulation. Specifically, the rate is slowed down to make degraded speech
more comprehensible, or is speeded up for fast scanning of recorded messages. The
strategy applied here is based on a sinusoidal transform system that models speech
waveforms as the sum of sinusoids with specific frequencies, amplitudes, and phases.
One usual way to eliminate the need of phase coding is to exploit a minimum-phase
system whose log magnitude and phase are uniquely related through a Hilbert
transform. Recent studies, however, indicate the inadequacy of the minimum-phase
assumption for modeling voiced speech due to the anticausal nature of the glottal
excitation. Recognizing this, we attempt to capitalize more fully on the properties of
speech production mechanism and then develop a noncausal all-pole modeling of
vocal system that enhances the accuracy of phase representation. In the harmonic
sine-wave model for time-scale modification, the parameters which are time-scaled
are the length of speech frame, the length of overlap-add interpolation window, and
the onset time of the glottal pulse.
NSC89-2614-E009-002 (89N229)
-------------------------------------------------------------------------------------------------------

Title:Design of CBR Service Guarantee Disciplines in ATM Networks
Principal Investigator:Po-Ning Chen
Sponsor:National Science Council
Keywords:ATM, Flow Control, Quality of Service

      Future high-speed/ATM networks are expected to carry diverse traffic types
with different requirements of quality of service(QoS), supporting services for traffics
with constant-bit-rate(CBR), real-time variable-bit rate(rt-VBR), none-real-time
variable-bit-rate(nrt-VBR), available-bit-rate(ABR) and unspecified-bit-rate(UBR).
The ultimate objective of providing guaranteed QoS networks is being approached by
the development of advanced techniques in traffic shaping, admission control, flow
control and congestion control. The use of admission control and traffic shaping
prevents networks being unexpectedly overwhelmed by excessive traffic. Flow
control, which involves traffic scheduling and/or regulation at network switching
nodes, aims to guarantee traffic characteristics of each serviced session. Congestion
control directs the cooperation of network nodes to reduce temporal variance of
aggregate traffic statistics over networks. Fundamentally, these require a framework
of flow control with feasible parameters for traffic specifications and management.
The CBR service is intended to support real-time applications that require tightly
constrained delay variation, such as voice, video and circuit emulation. The
mechanisms to guarantee QoS for CBR applications and flow control are currently
one of the main research areas for ATM technologies.
      The objective of this project is to develop and analyze flow control schemes to
efficiently predict and control the QoS, demanded by heterogeneous applications in
an integrated service network. Focused issues include: (1) development of effective
flow control mechanisms that provide high degree of isolation between connections
for performance guarantee, and at the same time, will not preclude statistical
multiplexing; (2) design of flexible and simple integrated service disciplines that will
impact the implementation of QoS guaranteed ATM networks at high-speed operation;
(3) establishment of mathematical structures for examining the end-to-end
performance of integrated traffic scheduling mechanisms deterministically and/or
stochastically on a sample path basis. In particular, the project in the second year will
focus more on the traffic aggregation for scalability, and the development of filtering
approach in guaranteed service networks. Generally speaking, traffic aggregation
policy based on virtual path connections can reduce the requirement on scheduling
and computing at the intermediate nodes of a virtual circuit. However, its service
discipline needs to exhibit highly isolation of allocated resources and delay bounds.
On the other hand, those based on grouping traffic rates can reduce computation
complexity at each switch scheduler on a virtual circuit. But this requires a service
discipline that is inherently simple in implementation. We will devote part of our
efforts in this project in devising a scheme that compromises the above twos.
Furthermore, the use of the (min, ) algebra for network calculus is a new trend. The
filtering approach is of great success in analyzing networks of guaranteed service
succinctly. It will be more significant that this approach is developed to yield new
solutions for QoS control. We will also try to research along this line.
NSC89-2213-E009-106 (89N328)
-------------------------------------------------------------------------------------------------------

Title:Investigation on the System Technology over High-Speed Wireless Local Area
       Network
Principal Investigator:Po-Ning Chen
Sponsor:Chung-Shan Institude of Science and Technology

Keywords:Wireless LAN, CSMA/CA, Communication System, OFDM


     In this project, under the system demands of high-speed wireless local area
network (LAN), we investigate the potential bottlenecks in the system development so
that a cost-effect partition between the components and the software modules is
obtained.
     Pushing to high-speed transmission is without a doubt a trend of the wireless
LAN standards. It is anticipated that the high-speed version (>10Mbps) of IEEE
802.11 will be finalized by the end of 1999. As seen from the medium access controls
(MAC) design of the existing IEEE 802.11 products, a CPU-based approach is
widely-adopted. Specifically, these products implement the CSMA/CA module in
terms of an embedded code (firmware), such as a 8086 code for 80188-based
AMD79C930. Such implementation methodology is quite different from that used in
Ethernet, which implements MAC on a specifically designed chip. Although a
firmware-based implementation is easy in maintenance and flexible to standard
revision, it may render a moderately high cost, and hence, may not be a cost-effect
solution for lost-cost-in-nature LAN products. In addition, the transmission speed is
by no means limited by the performance of the CPU. Accordingly, when high-speed
becomes a demand, a new implementation system structure is necessary. In this
project, we will study and propose a cost-effect partition between the specifically
designed components for MAC and its associated software modules executed at host
(in a form of a driver). It is our hope that this new structure can not only fulfill the
future need of high-speed transmission but also meet the low-cost nature of the LAN
products.
     For baseband part, both DSSS and FHSS are selected for current 2Mbps WLAN.
Though Harris Corp. has proposed a new modulation method, named complex code
keying or CCK, for higher data rate using the same IF band, BER becomes degraded
at the same SNR. As a result, it is necessary to explore other modulation methods to
enhance data rates. OFDM is just one of the possible solutions and has been used in
DAB and DVB in Europe. In this research project, we’ll investigate the possibility of
using OFDM for high data (over 10Mbps) wireless LAN and compare its system
behavior and performance with CCK approach.
I89022 (89.01.18- 89.12.18)
-------------------------------------------------------------------------------------------------------

Title:Applications and Researches Based on a Spontaneous Speech Database
Principal Investigator:Sin-Horng Chen
Sponsor : Computers, Communications, and Consumer Electronics Industrial
         Technology Research Institute Created by the Information Center
Keywords:Spontaneous Speech Recognition, Extralinguistic Phenomena,
               Out-of-Vocabulary, Acoustic Modeling, Prosodic Features


      Two main issues in spontaneous speech recognition will be studied in this project.
One is the processing of extralinguistic phenomena existing in spontaneous speech.
The other is the detection of out-of-vocabulary words. In the first issue, events of
extralinguistic phenomena are categorized into three classes according to their
acoustic characteristics and dealed with separately in three different ways. First, for
the events of breathes, coughs, hesitations, and environmental noise, acoustic
modeling is done through specific phonetic units and taken as any other word in
speech recognition. Second, for repetitions, repairs or paraphrasing, interruption
words, and pauses, appropriate prosodic features are extracted and used to detect them
for correcting the recognition results suffering from discontinuities. Third, for
speaking-rate varations, speech segmentation is done to provide explicit timing cues
for assisting in speech recognition. In the second issue, a new approach is adopted to
detect out-of-vocabulary words. It uses a strategy of penalizing the alternate models
formed by all base-syllables (or subsyllables) HMM models or rewarding the models
of in-vocabulary words. The project aims at making the technology of spontaneous
speech recognition available for the future use in developing spoken language
dialogue systems.
C89001 (88.7.1-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:Speech Input and Output Interface of Computer for Blind Users
Principal Investigator:Sin-Horng Chen
Sponsor:National Science Council
Keywords:Mandarin Speech Recognition, Information Inquiry, Internet, Blind User,
               Language Model, Bilingual TTS System.


      The goal of this three-year project is to develop a speech input and output
interface for blind user to use computer for information inquiry through Internet. In
the first two years, we have developed a basic on-line, Mandarin speech input-output
system. The input part is a large-vocabulary isolated word recognition system and the
output part is an RNN-based Mandarin TTS system. In the third-year project, we will
continue our research to use the basic on-line Mandarin speech input-output system to
develop several dialog-based applications. They include: (1) Internet news reading; (2)
Information inquiry and book borrowing system for blind library located in Tsing
Hwa University; (3) Electric book reading; and (4) Email reading system (developed
together with Sub-project 4). Besides, the speech input part, which is a
speaker-independent word recognition system, will be improved to make it more
robust to speaker variability.
NSC89-2614-E009-001 (89N228)
-------------------------------------------------------------------------------------------------------

Title:Development of Mandarin Speech Recognition Systems(III)
Principal Investigator:Sin-Horng Chen
Sponsor:National Science Council

Keywords : Mandarin Speech Recognition, Noise Compensation, Channel

                  Compensation, Speaker Normalization, Robust Training Algorithm


      This is the final year of a three-year project. The goal of the project is to
develop a prototype system of continuous Mandarin telephone speech recognition for
information inquiry applications. It is known that telephone speech recognition is still
a difficult task. The speaker variability, channel distortion, and background noise
interference are three main factors that seriously degrade the performance of the
recognition system. All key issues related to the task will be studied intensively.
      In the second year of the project, a preliminary study using the simulated
telephone speech has been done. An HMM-based baseline system has been
implemented. Besides, a segment-based C0 adaptation method for noisy speech
recognition and a robust training algorithm for adverse Mandarin speech recognition
have also been proposed.
       In the third year, we will extend the baseline system in the following four
aspects. First, an improvement of the SBR method based on a board-class
classification of the input signal will be studied. Second, a new signal bias estimation
method for channel effect compensation will be studied. Third, the robust training
algorithm proposed previously will be extended to consider the joint compensation for
noise, speaker, channel and loudness effects in order to train robust HMM models
from the MAT-2400 database. Last, a fast demo system of robust telephone speech
recognition using pre-segmentation and beam search techniques will be implemented.
NSC89-2213-E009-120 (89N334)
-------------------------------------------------------------------------------------------------------

Title:Designs of Near-Millimeter-Wave Array Antenna and Retrodirective Array
       Reflector for Vehicle Collision Avoidance System
Principal Investigator:Shyh-Jong Chung
Sponsor:National Science Council
Keywords:Vehicle Collision Avoidance System, 24 GHz Microstrip Antenna
               Array, 24GHz Amplifier, 24 GHz Active Retrodirective Array
               Reflector


      A 24 GHz microstrip antenna array and a 24 GHz active retrodirective array
reflector will be designed and demonstrated in three years. The antenna array is to be
used as the front antenna of a vehicle collision avoidance sensor, and the reflector is
proposed to be equipped on the vehicle body to enhance the radar echo over a wide
range of wave incidence angles. The microstrip antennas, which possess a planar
configuration, are adopted as the unit elements for both the designs. Also, the
microstrip lines are utilized for the feedings and connections of the antennas. In the
first year, a single 24 GHz microstrip antenna and various microstrip-line
discontinuities for the feeding network of the antenna array have been designed. In
the second year, an 88 microstrip antenna array and a 24 GHz small-signal amplifier
will be developed. The array is expected to possess a main-lobe beamwidth of about
10 to 15, a gain of 20 dBi, and side-lobe levels lower than -25 dB. The small-signal
gain of the amplifier is about 9 dB. In the last year, an active retrodirective array
reflector is to be completed. The reflector is composed of several antenna pairs, each
including two microstrip antennas and two small-signal amplifiers, connected by
microstrip lines. By suitably arranging the positions of the antennas and the lengths of
the connecting lines, the antennas in the array reflector can coherently reradiate the
received illuminating wave toward the wave-incidence direction, over a large range of
about 100 of the incidence directions.
NSC89-2213-E009-050 (89N284)
-------------------------------------------------------------------------------------------------------


Title:Development of A Passive Microwave Transponder for Vehicle Short-Range
       Communications
Principal Investigator:Shyh-Jong Chung
Sponsor:National Science Council
Keywords:Vehicle Short-Range Communications, 5.8GHz Passive Transponder,
               Circularly Polarized Microstrip Antennas, Retrodirective Antenna Array,
               ASK MODEM Circuits


     A low-cost 5.8GHz passive transponder for vehicle short-range communications
is to be designed and developed in two years. The transponder is composed of
circularly polarized (CP) microstrip antennas and binary amplitude shift keying (ASK)
modulation-demodulation (MODEM) circuits. To reduce the transponder size and the
influence of the circuits on the antenna radiation pattern, the configuration of
two-layer substrates separated by a ground plane is utilized in the design. The signals
are transferred between the antennas and the microstrip feed lines through apertures
on the ground plane. The transponder uses a passive design to save the required power.
Under the considerations of enhancing the transponder echo and the resultant overall
size, two parallel-placed linear antenna arrays, each with four CP microstrip antennas,
are implemented in the transponder.
      The first antenna array is designed to produce a microwave echo to the roadside
beacon, which will be accomplished in the first year. The Van Atta retrodirective array
design is used for the routing of the antenna feed lines. The two peripheral antennas
are paired by a microstrip line, and the middle two are paired by another microstrip
line with the same length. There is a bilateral diode switch on the way of each
microstrip line, both of which are controlled by a binary encoding circuit. The signal
received by each antenna, after encoded, is directly fed to the antenna of the same pair
and is then re-radiated to the roadside beacon. Due to the retrodirective design, the
fields re-radiated from the four antennas are coherently added at the interrogator
(beacon) direction, so that, without increasing the consumed power, the transponder
echo of the present design has a strength 12dB higher than those of the traditional
transponders. Thus, the communication range and the sensitivity can be enhanced
greatly. The power source of the present transponder is provided by an embedded
battery, which is mainly consumed in the encoding circuit. To increase the life of the
battery, the battery is put in a stand-by status when no communication is needed.
     The second antenna array and the related circuits will be finished in the second
year. The function of this array is to demodulate the interrogating microwave signal to
a binary base-band signal. Also, the demodulated dc power will be utilized to trigger
the embedded battery. Four zero-bias Schottky barrier detector diodes are separately
implemented on the outputs of the four array antennas. The microwave signal
received by each antenna is directly passed to the detector diode and a low-pass filter.
The obtained base-band signals are then combined as the final output. Since the
signals from the antennas are added at the base band but not at the microwave
frequency, the receiving pattern of the whole array will be the same as that of a signal
antenna. Furthermore, since the final output is the combination of the signals received
by four antennas, the receiving sensitivity of the present transponder will be 12dB
higher than those of the traditional ones.
      The two antenna arrays and the related circuited will be integrated in the
second year. The overall size of the finished transponder is estimated to be smaller
than 10×15, so that it is feasible to put the transponder inside the front windshield of a
vehicle. Actually, to reduce the transponder size, the second antenna array could be
omitted by directly mounting the detector diodes on the antennas of the first array.
But, since part of the received microwave power would be transferred to the dc and
base-band signals, the re-radiated fields from the antennas of the first array would
thus be weakened, which, in turn, would reduce the transponder echo.
NSC89-2213-E009-054 (89N287)
-------------------------------------------------------------------------------------------------------

Title:Analysis and Implementation of Near Field to Far Field Transformation
Principal Investigator:Shyh-Jong Chung
Sponsor:I.T.R.I.
Keywords:Near-Field Measurement, Equivalent Far Field, Equivalent Magnetic
               Currents


        In this project, the method of equivalent magnetic currents (EMC), which is
derived from the equivalence principle and the image theorem in electromagnetics, is
to be adopted to transform the measured near radiation field to the equivalent far field.
By using the measured amplitude and phase of the near field, the equivalent magnetic
currents located at suitable positions are first solved through the conjugate gradient
method (CGM) and the fast Fourier transform (FFT). These magnetic currents have
the same radiation near field as the measurement. The free-space Green’s function
together with the FFT is then used to calculate the far field radiated from the currents.
A software package for transforming near filed to far field will be implemented during
the period of this project. Furthermore, the possibility of transforming near field to far
field by using measured near-field intensity only is also studied.
C89060 (88.09.01-8908.31)
-------------------------------------------------------------------------------------------------------

Title:On the Communication Protocols for the Intelligent Transportation System
Principal Investigator:Shyh-Jong Chung
Sponsor:Ministry of Transportation and Communication
Keywords:ITS, Communications Networks, Evaluation Modes


     Intelligent transportation systems (ITS) comprise a wide range of novel tools for
managing transport networks as well as services for travelers. ITS tools are based on
three core features: information, communications, and integration. The collection,
processing, integration and supply of information are at the heart of ITS.   Whether
offering real-time information about current traffic conditions for a network, or
on-line information for journey, ITS tools enable authorities, operators, and individual
travelers to make better informed, more coordinated, and more intelligent decisions.
Most of the ITS applications have some components involving the flow of data or
voice messaging between vehicles, remote sites, and coordinated control centers.
Thus, communications, especially wireless communications, are essential for these
applications. The ultimate selection of particular communications systems will
greatly affect the viability of any ITS network, so this decision must be based on a
clear understanding of the costs and other performance parameters of the various
technologies available. It is the purpose of this project to review and evaluate
suitable communication networks for ITS applications, based on a thorough study of
ITS communication needs.
C89168 (89.01.21-89.11.20)
-------------------------------------------------------------------------------------------------------

Title:Acoustical Echo Cancellation for Bands-Free Mobile Phone
Principal Investigator:Shih-Fu Hsieh
Sponsor:National Science Council
Keywords:Echo Cancellation, Mobile Phones, PN Sequence, Common-Pole, Noise
               Control


       With the advent of ubiquitous mobile phones, personal speech communication
demandsa higher and higher quality. In particular, a hands-free mobile phone shows
its promising potential in a very near future. Though the car cabin has a very limited
chamber room acoustical echoes still arise due to the coupling between the
loudspeakers and microphones. We aim to deal with the acoustical echo cancellation
for mobile hands-free phones.
       In the past, time-sharing method only allows half-duplex oral communication,
while complementary comb filters tend to degrade the speech quality. With effective
cost down of VLSI and DSP technologies, LMS and RLS adaptive filters attracts wide
a lot of research interests, with focus on such aspects as double talk detection, variable
step size, speech decorrelation as well as conventional adaptive filters issues such as
FIR/IIR, lattice, subband, frequency domain methods, etc.
       We will focus on the Maximum-length sequence method. Three adaptive
PN-sequence algorithms will be proposed and compared. Statistical analysis and
computer simulations a mobile environment will be performed. We will also look into
the common-pole acoustical echo cancellation model in the car cabin as well as
incorporating the active noise control technology to provide an effective and high
quality hands-free mobile phone systems.
NSC89-2213-E009-135 (89N337)
-------------------------------------------------------------------------------------------------------

Title:Design and Simulation of a Digital Baseband Receiver Architecture for an
       IS-95 Handset
Principal Investigator:Chia-Chi Huang
Sponsor:National Science Council
Keywords:CDMA, IS-95, Spread Spectrum, RAKE Receiver, Synchronization


       Code Division Multiple Access (CDMA) is a key technique for cellular mobile
radio and personal communication systems. The IS-95 radio transmission technology
is a spread spectrum radio interface standard that uses code division multiple access
(CDMA) technology to implement a cellular mobile telephone system in North
America. In this project, we will design a digital baseband receiver architecture for a
handset according to the IS-95 standards, which is suitable for VLSI implementation.
The digital baseband receiver architecture design will be divided into two parts. One
part is to design a synchronization subsystem architecture and the other part is to
design a RAKE receiver architecture. We plan to simulate and analyze the
performance of the designed receiver architectures on a computer. At the end of this
project, we will provide both algorithms and block diagrams of this digital baseband
receiver architecture for the future IC design of an IS-95 digital baseband receiver in
Taiwan.
NSC89-2213-E009-083 (89N306)
-------------------------------------------------------------------------------------------------------
Title:2-Dimensional RAKE Receiver Architecture Design
Principal Investigator:Chia-Chi Huang
Sponsor:Chunghwa Telecom Laboratories
Keywords:2-D RAKE Receiver, DFT Beamforing, Antenna Array


     In this project, we will design a two dimensional RAKE receiver architecture,
which is a spatial-time matched filter. An antenna array is installed in a base station
and is used to estimate and orient to the direction of the received signal through DFT
beamforming. Then, we apply a conventional RAKE receiver to process the
beamforming signal. In this way, the interference from other directions can be reduced.
We will simulate the system performance in a multipath fading channel and calculate
the increased system capacity.
C89079 (88.08.01-90.01.31)
-------------------------------------------------------------------------------------------------------

Title:A Study on WB-CDMA/WLL Multiuser Detector
Principal Investigator:Huang Chia-Chi
Sponsor:Chung San Institute of Science and Technology
Keywords:CDMA, Uplink Receiver, 3GPP, Multiuser Detector


       In this project we will design and simulate a single user uplink receiver
architecture and an FFT-based multiuser detector. The uplink receiver designed in the
previous year project will be modified to adapt to the 3GPP specification. We will
discuss the effect of both “pilot symbol length” and “decision feedback channel
estimation” on receiver performance. In the FFT-based multiuser detector, we will
design a spreading code matched filter, a channel matched filter ,and a signal
reconstruction filter in the frequency domain. At the end of the project, we will
provide both simulation results and block diagrams of this receiver architecture for
future IC design.
I89028 (89.03.01-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:Development of X/Ku Band 4 Bits MEMS Phase Shifter
Principal Investigator:Christina Jou
Sponsor:National Science Council
Keywords:MEMS, Phase Shifter, Microswitch
       This project is to develop new prototype Ku-band 4 bits phase shifter with low
insertion loss, using the microelectromechanical systems (MEMS) technology which
have promoted exciting advancements in the field of microwave switching recently.
       Phase shifter can be used to control the phase of RF signal through switching of
different transmission paths. RF MEMS switches will be used to replace traditional
p-i-n diode or FET devices in phase shifter circuit in this study. It can be actuated to
ON or OFF state through electrostatic force, and the RF signal path will be connected
or disconnected. Figure 1 shows the basic operation principles of RF MEMS switch.

      RF I n p u t To p Me mb r a n e RF O u t p u t



                              Si Subs tr at e


       Po s t                C o n t r o l Pa d

                  ( a)   OFF St at e



      RF Input                         RF Output
                   Top Membrane




                             Control Pad
                 (b ) ON


                 Figure 1. Basic operation principle of RF MEMS switch


    As a example of phase shifter, figure 2 is a 3 bits circuit, S1 to S6 represent the
RF MEMS switches.


           IN                                                               OUT
                               S1                  S3            S5


                                  S2
                                                   S4
                                                                  S6
                  Figure 2.Schematic of 3 bits phase shifter


       RF signal enter the circuit from input port, when S1 , S3, S5 are actuated to ON
state, and S2,S4,S6 are actuated to OFF state, the RF signal will have the minimum
phase relative to other definitions of the 3 bits switches. Totally, there are 8 different
phase states which the input RF signal can be tuned.
     This study will cooperate with Professor N. C. Luhmann from University of
California, Davis in USA. He is the chairman of electrical engineering department at
UCDavis. He was also the advisor of this author. Professor Luhmann has been
working in RF area over 20 years, the researches in his laboratory cover almost all the
important issues about traditional RF switches and its system applications, such as
switch delay line, quasi-optical phase shifter, phase antenna arrays, their efforts has
acquired much respect from the world. We will work together to develop various high
performance RF MEMS phase shifters.
      In addition, this study will link with Antenna and LNA subgroup to develop the
prototype of front-end RF subsystem. It is our deeply hope that the project will have
potential in industrial applications, except the academic research values.
      The MEMS phase shifter will be fabricated at the facilities of Semiconductor
Research Center and National Nano-Device Laboratory in NCTU. The process
technologies will be backed up and developed by the RF MEMS process group in the
other sub-project.
       The project will be divided into 3 years. First, we will concentrate on design,
layout, simulation and modeling of MEMS switches. In the 2nd year, we will
concentrate on building the test facilities for the measurement of DC and frequency
domain characteristics; base on the results from the measurement and simulation, we
will design and simulate the MEMS phase shifter. In the 3th year, we will concentrate
on characterization of MEMS phase shifter, and performance evaluation in the
integrated front-end subsystem with antenna and LNA devices.
NSC89-2218-E009-008 (89N414)
-------------------------------------------------------------------------------------------------------

Title:Quasi-Optical Solid-State Beam-Scanning Active Antenna Arrays
Principal Investigator:Christina Jou
Sponsor:National Science Council
Keywords : CPW, Monolithic, Beam-Scanning, Traveling Wave Antenna,
                 Leaky-Wave Antenna


     Current research interest in millimeter wave system is motivated by the
advantage such as smaller antennas, wider bandwidths, and better resolution for
imaging and radar system. However, this natural progression from the microwave to
millimeter wave spectrum has been hindered in many cases by the lake compact,
reliable, high power solid-state source at these wavelengths. The advances in device
technology make wafer-scale integrated power combining sources very attractive. In
addition, free-space power combining is more efficient at high frequencies than power
combining in guided wave structure, and transmitting and receiving system based on
monolithic implementation have the potential to be smaller, lighter.
       Quasi-optical techniques spurred the development of active integrated power
combiner in 1980's 1990's. As the operating frequency increases, the available power
from solid state device decrease. Therefore, power combining of solid-state devices
using quasi-optical techniques in the millimeter wave region became an important
issue. There are two different approaches for quasi-optical power combining. One is
the active antenna approach and the other is the grid approach.
      The advantage of active antenna is:(l) increasing the effective length of short
antenna (2) increasing the band-width (3) decreasing the mutual coupling between
array elements (4) improving the noise factor. From the forgoing advantages, we can
see active devices and passive patch antenna fabricated on the same substrate can
improve antenna performance. The technology of monolithic microwave active
integrated circuit is mature, and makes the approach promising. In the 1995-1997
project, we had successfully demonstrated the active phase-shifterless beam-scanning
patch antenna array. In that project we had learned from design, fabrication and how
to test the whole circuit, and how to use the nonlinear CAD tool to simulate the
learned that the oscillation frequency was limited mainly due to the ft of the HEMT
and the device packaged figuration. Meanwhile, due to the narrow bandwidth of the
patch antenna, the scanning angle of the antenna array was limited by 11 degree. It is
not large enough to use in commercial application. In order to solve the narrow
bandwidth of the antenna array and scan widely, we find out another types of the
antennas, the traveling wave antenna and the leaky-wave antenna, and have the first
analysis.
      In our first analysis, we find the advantages of the traveling wave antenna and
the leaky-wave antenna, such as the wide bandwidth, the high efficiency and the high
power. In this project, we will design fabricate and test a monolithic quasi-optical
active-integrated beam-scanning antenna array, including the traveling wave antenna
and the leaky-wave antenna, to have more power and scan more angle. We will
demonstrate two topologies of the antenna arrays. The planar active antenna array,
which integrates the active signal source, the HEMT VCO circuit, and the planar
feeding antenna array on the same plane of the substrate, have the simple structure
and the low noise of the circuit. The other topology is the CPW (Coplanar
waveguide)-slotline-antenna,the signal is fed to antenna via the slotline. The active
source uses the Gunn diode as the device of the oscillator. Gunn diode has the
advantages of the simple bias circuit and the higher ft and higher power, in order, to
elevate the oscillation frequency.
       In first year, we will measure the parameters of the active devices, HEMT and
Gunn diode, model the devices and simulate the HEMT VCO circuit and the Gunn
diode oscillator circuit using the commercial CAD, Libra. The model setup of the
active devices has the good precision between the simulated circuit and the fabricated
circuit. The analysis and demonstration of the single antenna will be also done in the
first year. In the second year, the scanning antenna array will be demonstrated and be
integrated with the HEMT VCO and the Gunn diode oscillator on the same substrate.
The whole antenna system will be carefully measured and analyzed by using the
full-wave method. The direction of the main beam of the active planar and the active
CPW antenna arrays can be controlled by varying the bias voltage. Because of the
wide bandwidth of the traveling antenna and the leaky-wave antenna, the beam
direction will scan during the wide angle; meanwhile, the radiated power efficiency
can increase due to the perfect characteristic of the input impedance of the antenna.
     In the past years, the professor Jou has demonstrated many topologies of the
active antenna arrays, including the patch antenna arrays and the grid arrays. She is
also one of the pioneers of the quasi-optical circuit design. The assistant professor Wu
has investigated the research of the dielectric material and the characteristic of the
propagation of the EM wave for many years. It is believed that the widely scanning
angle and the high power active antenna arrays will be demonstrated successfully in
this project.
NSC89-2213-E009-056 (89N452)
-------------------------------------------------------------------------------------------------------

Title:Investigation of Trinary Coding in Synchronous Spread Spectrum Systems
Principal Investigator:Ming Seng Kao
Sponsor:National Science Council

Keywords:Spread Spectrum Communications


       Conventional spread spectrum communications employed binary spreading
codes (+1,-1) to spread and despread the transmitted data. Because c(t)=1, thereby
c2(t)=1 and the transmitted signal could be recovered at the receiving end through the
despreading process. The study of binary spread spectrum systems was quite mature,
and the resultant advantages had been well recognized in practical communication
systems.
      This project intended to investigate the feasibility of a novel spreading codes in
the spread spectrum communications by using trinary codes (+1,0,-1). As c2(t)=1 or
0 if trinary codes were used, the original waveform of the transmitted data could not
be recovered. However, in digital communications the important task of receiver is
not to recover the signal waveform but to accurately decide which one of logic ”1” or
“0” was transmitted. Although the original waveform of data bits could not be
recovered after despreading process, accurate decision was still possible if suitable
signal processing was performed. Therefore trinay coding was applicable in spread
spectrum systems and several related issues were of interest:


                   1. Search of trinay orthogonal code sets
                   2. The cross-correlation property of trinary code sets
                   3.   The comparison between trinary codes and binary codes
                   4.   Multiple interference problem
                   5.   Signal detection at the receiving end
                   6.   Possible applications


     In this project we would theoretically investigate the proposed trinary coding. If
the result was sound we would like to implement a simple system in the future to
demonstrate its applicability.
NSC89-2213-E009-086 (89N309)
-------------------------------------------------------------------------------------------------------


Title:2.4GHz CMOS RF Front-End Circuits Design(Ⅱ )---2.4GHz Mixer

Principal Investigator:Yao Huang Kao
Sponsor:National Science Council
Keywords:CMOS, RF IC Front-End Circuit, Conversion Gain, Linearity NF, Cutoff
               Frequency


       Owing to low power consumption , low cost , and high integration , CMOS
technology applied to rf integrated circuits has received much attention in wireless
communication. In this year a mixer by Gilbert cell at 2.4GHz is proposed. This is the
second year work for our target in rf front end , which normally includes low noise
amplifier , mixer , and local oscillator.
       Mixer is the frequency conversion element , whose input interception point
(IIP)is essential for dynamic range in receiving system . It is known that the status of
cmos mixer are conversion gain=0.5dB , NF=10.02dB , and dynamic range=-15dB at
1.9GHz . In this project , our 2.4GHz Gilbert cell mixer is to be fabricated from
TSMC or UMC process , which is expected to be well enough for the rf IC process.
The trade off is made between dynamic range and conversion gain by trimming the
emitter-coupled resistor. It is expected to have conversion gain equal to 0dB.
According to our preliminary study , the gain of a two-stage low noise amplifier in
cascode configuration is about 12.5dB and NF in about 5.2dB , which seem to be
quite well as compared to those in the literature. The related rf modeling is also to be
intensively investigated. In the future a end circuit are planned. We expect that with
such studies the CMOS technology , which is conventionally used to digital circuit ,
can be applied to analog rf circuit for wireless applications.
NSC89-2213-E009-055 (89N288)
-------------------------------------------------------------------------------------------------------

Title:Linearizer for Ka-Band High Power Amplifier
Principal Investigator:Ming Seng Kao
Sponsor:Mental Data system

Keywords:Predistortion, TWT, Waveguide Transition


     Recently the microwave transmission system of LMDS has received much
attention for its easy construction. In this application, the linearity of the power
amplifier is essential for transmission quality and channel numbers. Two types of
power amplifiers of solid state and traveling wave tube(TWT) are commonly used. In
this project a predistortion module is to be fabricated for the 28GHz (TWT). Two
subcircuits are studied. One is the waveguide to microstrip line transition, and the
other is the compensation circuit, which operates at 28GHz. Amplitude and phase
compensation are both considered.
C89083 (88.10.01-89.09.30)
-------------------------------------------------------------------------------------------------------


Title:Linearization of High Power Amplifier For Mobile Communication


Principal Investigator: Yao-Huang Kao


Sponsor:Remotek Corp.


Keywords:Cross Modulation, Intermodulation, AM to PM Effect:




        This project research the RF power amplifier linearity. The RF power
amplifier is usually the most important and expensive component in a wireless
communication          system . We           study and implement the predistortion and
feedforward linearizing techniques for the RF PA to minimize the IMD under -30
dbc.This will decrease the AM-AM and AM-PM effects in the output signals of the
wireless communication system.So can acheive the two tone test specification of
modern wireless communication system.
C89240 (89.07.01-90.06.30)
-------------------------------------------------------------------------------------------------------

Title:Planar Microstrip Filters with Transmission Zeros at Real or Imaginary
       Freguencies Using Compact Minuatarized Hairpin Resonators
Principal Investigator:Jen Tsai Kuo
Sponsor:National Science Council
Keywords:Wireless Local Area Network (WLAN), Compact Miniaturized Resonator,
               Microwave Integrated Circuit, Filter Synthesis


     These proposal aims at developing very small-sized planar microstrip filters of
various types for use in the RF front end of LAN’s (wireless local area networks).
The structure allows nonadjacent electromagnetic coupling to be realized and adjusted.
The coupling coefficients for each basic coupling structure can be obtained, by
full-wave simulators, based on the calculated split resonant requencies. In addition to
Chebyshev function, the four-pole elliptic function and linear-phase filters are to be
designed and fabricated.       The basic resonator used here is the microstrip
miniaturized hairpin resonator, of which the area is very compact. Based on the filter
synthesis theory, proper electromagnetic couplings between the resonators have to be
properly established according to the filter specification, the size of the whole
structure can thus be miniaturized. As a result, for a four-pole elliptic function filter
of 2.4GHz center frequency constructed on a substrate with 20mil thickness and
                                                2
  r=10.2, the overall area is about 1.2cm .

NSC89-2213-E009-057 (89N289)
-------------------------------------------------------------------------------------------------------


Title:Algorithm and Software Radio Realization of Space-Time RAKE Receiver
Principal Investigator:Ta Sung Lee
Sponsor:National Science Council
Keywords:Wireless Communications, CDMA, Smart Antenna, RAKE Receiver


       The smart antenna represents one of the emerging and key technologies in the
third-generation mobile communication systems (IMT-2000). The major function
of a smart antenna lies in the enhancement of effective signal-to-interference ratio via
spatial division multiple access, thereby achieving an improved communication
quality and capacity. Due to the rapid advancement of DSP chips, realization of
smart antenna technology via software radio is becoming feasible. Along these lines,
the goal of this proposal will be on the study of the algorithms and software radio
realization of smart antennas for wideband CDMA (W-CDMA) systems. Specifically,
the approach of so-called space-time 2-D RAKE receiver will be taken to integrate
the degrees of freedom offered by the smart antenna (spatial) and conventional
RAKE receiver (temporal) to develop a space-time joint processor. Various types of
2-D algorithms have been investigated, and the feasible ones will be realized using
DSP firmware techniques.
      The DSP work in this proposal will be mainly based on our previous year’s
research results on W-CDMA smart antenna and 2-D RAKE receiver. Two sets of
DSP modules (TMS320C6X) will be employed to simulate the software radio
structure. In particular, one of the module will be used as a signal generator to
produce simulated W-CDMA signals representing what are observed at the base
station antenna array. The other module will be used as a 2-D RAKE receiver to
perform signal reception and demodulation. The operation of the entire DSP system
can be controlled by a host PC or workstation, with the algorithms first simulated and
evaluated then down loaded via real-time OS to the board. This should enable the
seamless connection from simulation, debugging to final realization. Finally,
integrated experimental trial will be performed with other co-proposals to ascertain
the efficacy of the 2-D RAKE receiver.
NSC89-2219-E009-005 (89N013)
-------------------------------------------------------------------------------------------------------

Title:Blind Multiuser Detection for CDMA Systems
Principal Investigator:Ta-Sung Lee
Sponsor:National Science Council
Keywords:Blind Multi-User Detection, Array Signal Processing, CDMA Systems


      Conventional multi-user detection (MUD) methods for CDMA systems
typically work with a training signal to obtain the channel information, and achieve
interference suppression via the MMSE criterion. On the other hand, blind MUD
needs only to know the desired user’s signature waveform and timing to perform the
same detection. This alleviates the bandwidth inefficiency due to the use of training
signal.
         Recent developments on blind MUD are usually based on the AWGN
assumption. This is not the case in a real world mobile communication system.
This is a problem that needs to be tackled with. In this proposal, the minimum output
energy (MOE) and subspace projection types of MUD will be investigated in terms
of property, performance and complexity. A detector based on the combination of
the GSC concept in array signal processing and MRC will be developed to
effectively handle signal reception in a multipath environment. Finally, the antenna
array will be incorporated to achieve the performance of space-time joint processing.
       This proposal will base itself on the third-generation mobile communication
system IMT-2000 in developing advanced blind MUD methods. Due to the fact that
aperiodic long codes will be employed in IMT-2000, the existing blind MUD methods
do not apply properly. This would necessitate further efforts.
NSC89-2213-E009-084 (89N307)
-------------------------------------------------------------------------------------------------------

Title:Study on the Architecture of Adaptive Antenna Array Technology for
       WB-CDMA/WLL Systems
Principal Investigator:Ta-Sung Lee
Sponsor:Chung San Institute of Science and Technology
Keywords:CDMA, WLL, Adaptive Antennas, RAKE Receiver


     In the planning of the third generation mobile communications, wideband
CDMA and adaptive antennas are two major key technologies. CDMA is a time
domain technology that exploits the temporal degree of freedom to perform multi-user
and multipath separation, whereas adaptive antenna is a space domain technology that
exploits the spatial degree of freedom to suppress interference and enhance multipath
diversity. A combination of both can thus effectively increase the system SIR and
thereby obtain a better communication capacity and quality. The major purpose of this
proposal is to study, based on the 3GPP W-CDMA standard, the suitable baseband
signal processing algorithms and architectures of adaptive antennas for the wireless
local loop applications. We will employ the concept of the space-time 2-D RAKE
receiver to integrate the temporal degree of freedom of CDMA and spatial degree of
freedom of antenna array into a larger operational dimension. In particular, we will
study in detail the subjects including beamforming, weight control, channel
estimation and RAKE combining. We will suggest the suitable algorithms for each of
the subjects, conduct simulations, performance analysis and feasibility evaluation so
as to ascertain the efficacy of using adaptive antennas in both theoretical and practical
aspects.
I89027 (89.02.15-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:QoS Control for Broadband Internet
Principal Investigator:Tsern Huei Lee
Sponsor:National Science Council
Keywords:Broadband Internet, Quality of Service, QoS Routing, Gigabit Router,
               Signaling, Policing, Scheduling, Network Planning, Management


      Continuous rapid growth of the Internet in recent years makes it the most
probable future integrated services network. However, current Internet architecture is
inadequate in providing real-time applications. It cannot guarantee delay bound
requirements of real-time applications. Moreover, non-real-time applications may
be terminated if real-time traffic causes congestion. Internet 2 is thus proposed to
meet future needs.
      Broadband Internet will undoubtedly face applications with wide quality of
service (QoS) requirements. In face of increasing traffic, to guarantee quality of
service (QoS) efficiently, it needs:
   (1) High-capacity (Gigabit) routers: to increase network capacity.
   (2) QoS routing: to improve network utilization.
   (3) Signaling: to characterize source traffic and reserve resources.
   (4) Admission control: to limit access of network resources.
   (5) Policing: to provide reliable QoS guarantee.
   (6) Scheduling: to provide different QoS.
   (7) Network Planning and Management: to monitor network performance and plan
       network volution.
In this project, we shall investigate all the above issues in seven sub-projects. Our
main purpose is to develop techniques which can be used in Broadband Internet.
Results obtained in this project will be patented and/or published in international
conferences and journals.
NSC89-2219-E009-003 (89N003)
-------------------------------------------------------------------------------------------------------

Title:Gigabit Router and Traffic Policing for Broadband Internet
Principal Investigator:Tsern Huei Lee
Sponsor:National Science Council
Keywords:IP Router, Crossbar Switch, Hardware Routing, Traffic Policing
      High-capacity router is an essential component for future broadband Internet to
handle rapidly growing traffic. The bottleneck for conventional routers is software
processing of routing information. Hence, to increase capacity, routing information
must be processed with hardware.
      In this sub-project, we shall investigate two key technologies of high-capacity
routers: switch architecture and longest prefix matching with hardware (or hardware
routing). Conventional bus-based architecture is not scalable because of clock rate
and pin count limitations. A capacity more than 12 Gbps is very difficult to be
realized with current technology.
      Space-division such as the crossbar architecture is thus necessary to build a real
large-capacity router. However, crossbar switches suffer from head-of-line (HOL)
blocking which limits the maximum throughput to about 50%. Longest prefix
matching is another bottleneck in IP routing. Unlike exact matching, hashing
cannot be easily utilized in IP routing. Putting routing table in silicon efficiently
seems to be the most widely acceptable solution in current stage.
       In this sub-project, we shall develop queue management and fast scheduling
algorithms to (partially) remove HOL blocking. In addition, we shall design
efficient hardware routing schemes to speed up routing decision. Traffic policing
for frame-based network and traffic classification are also investigated here. In
traffic policing, we shall focus on the leaky bucket algorithm. Our purpose is to
design efficient realization algorithm and implement it with FPGA technology. For
traffic classification, we shall design classifiers based on destination IP address,

source IP address, destination port number, source port number, and protocol ID。

Results obtained in this sub-project will be patented and/or published in
internationally recognized conferences and journals. To enhance the hands-on
experience, we shall also develop chips and possibly prototype a simple switch router
for the rest of two years.
NSC89-2219-E009-004 (89N004)
-------------------------------------------------------------------------------------------------------


Title:Design and Implementation of Multiple-Field Packet Classifier
Principal Investigator:Tsern-Huei Lee
Sponsor:ITRI
Keywords:Packet Classifier, Differentiated Services, Quality of Service Guarantee


     Today, the network environment is far more complex than ever before. Many
new distributed multimedia applications are carried, such as desktop video and data
conferencing, Internet telephony, distance learning and tele-medicine. These
applications have traffic characteristics and requirement that are different from
traditional data. They require not only increased network bandwidth but also
reservations for quality of service guarantees. These trends have resulted in intense
efforts to build packet forwarding engines that can perform traffic classification at
wire-speed. Now service providers are facing similar challenges. They have to have
the ability to provide differentiated service to different users in the same shared
infrastructure and customers also want have the flexibility to define different service
level for different types of traffic.
     One of the most important elements to support differentiated services is the
packet classifier. It needs to be capable of parsing the destination address as well as
other fields such as source address, TCP and UDP port numbers, protocol ID, and
perhaps differentiated service field for supporting QoS, firewalls, and normal unicast
and multicast forwarding. However, traditional routers are based on flow-cache
architectures to classify packets. They can't provide predictable efficiency at all times
and will easily become the bottleneck when the number of active flows is large.
      In this project, we emphasize on worst-cast performance rather than average
case performance. We should design a packet classifier algorithm that allows the rules
to be designed based on multiple fields and each field can be specified by ranges,
prefixes, or exact values. We shall also implement the designed packet classifier
algorithm. Another algorithm will also be developed for the special case of
two-dimensional lookups (for multicast routing).
C89069 (88.08.01-89.07.31)
-------------------------------------------------------------------------------------------------------

Title:Research on MAC Protocol for WB-CDMA/WLL
Principal Investigator:Tsern Huei Lee
Sponsor:Chung San Institute of Science and Technology
Keywords:State Machine, Specification, Quality of Service


       In the process of realizing a wireless communication system, it is common to

classify the whole system into hardware、firmware and software modules. The modus

can leave the teams work individually and simplify the debugging process when all
the modules are integrated. But all these three blocks should cooperate with each
other to realize the functions a system requires; therefore, designing good state
machines is the important first step to realize a wireless communication system.
      Generally speaking, there are some simple state machines defined in
specifications. However, details of these state machines often are not described. This
will give the developers some flexibility in realizing the system. It is clear that the
management of traffic channels is much more complicated for WB-CDMA than the
second generation CDMA because WB-CDMA have to provide various kinds of
services (including voice, packet data, circuit data, and their com binations). Besides,
WB-CDMA has to satisfy users with different quality of service (QoS) requirements.
      The goal of this project is to design realizable MAC layer state machines for
WB-CDMA systems. In particular, we shall consider the QoS module in defining state
machines. Developers should be able to realize the MAC protocol based on our state
machines.
I89031 (89.3.1-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:Millimeter Wave Imaging Array Design
Principal Investigator:Yu De Lin
Sponsor:National Science Council
Keywords:Millimeter-Wave Imaging Array, Leaky-Wave Antenna, Planar
               Transmission Lines


       The purpose of this project is to design the millimeter-wave imaging antenna
arrays for the quasi-optical millimeter-wave vision system proposed in the main
project. To be compatible with the active circuits and the feeding circuits designed in
other projects, the antenna arrays will be based on the leaky modes of the planar
structures. In the previous two years of the project, we have completed the analysis of
the propagation characteristics, feeding structure design, and pattern analysis of single
element leaky-wave antenna. We have also completed the design of a four-element
array in K-band. Measured results are in good agreement with the analysis data and
show the frequency-scanning feature of the leaky-wave antenna. In the third and final
year, we will continue to improve the efficiency and feeding network of the array.
Finally, the completed antenna arrays will be simulated and tested in the quasi-optical
vision system.
NSC89-2213-E009-073 (89N482)
-------------------------------------------------------------------------------------------------------

Title:Investigation on Application of Wideband Receiver
Principal Investigator:Yu De Lin
Sponsor:Chung-Shan Institute of Science and Technology
Keywords:Broadband Couplers, Microstrip, Coplanar Strip, Broadside-Coupled
               Mocrostrip


       Broadband receiver has widespread applications in electronic warfare. In it, the
design of microwave circuit is quite critical and challenging. For instance, the
broadband hybrid couplers (find applications in signal splitter, power combiner, image
injection mixer, and antenna feed network etc.) need tight-coupling sections that are
hard to realize in microstrip technology. Using the strip line technology has the
problems of bulky volume and manufacturing. In this project, we hope to develop the
broadband hybrid couplers in microstrip technology. The point is to design usable
tight-coupling sections. The usual approaches adopted now are broadside coupling
lines or Lange-coupler. In this project, we will use Variations of the microstrip line
such broadside-coupled microstrip line or coplanar strips to realize them.
D89003 (88.07.01-89.06.30)
-------------------------------------------------------------------------------------------------------

Title:Design and Investigation of Microstrip Antennas
Principal Investigator:Yu De Lin
Sponsor:Chughwa Telecom Laboratories
Keywords:Microstrip Antennas, Microwave Communication System


     There are many microstrip antennas well-documented In the literature. Yet, to
meet the specific requirement of the microwave communication system under
consideration, some antennas are more suitable than others . The purpose of this
project is to Investigate antennas that are suitable for the microwave systems designed
by the Smart Ant Telecomm Inc. After theoretical analysis of the antenna structures,
experimental measurement of the design formulas. The antennas will be fined-tuned
to meet the system specifications In the end .
C89186 (87.12.01-88.11.31)
-------------------------------------------------------------------------------------------------------

Title:Theoretical Study on Guidance Characteristics of Two Dimensionally Periodic
      Structures (Subprogram 1)
Principal Investigator:Song-Tsueng Peng
Sponsor:National Science Council
Keywords:2D Periodic Structures, PBG, Stop Bands, Band Gaps


      Periodic structures have been widely use for the design of components and
devices in many engineering applications. Extensive theoretical and experimental
results on periodic structures are available in the literature. But most of the work had
been mostly limited to the case of one-dimensionally periodic structures. Recently,
two-dimensionally periodic structures have demonstrated to be useful for the
suppression of surface waves in the strip-type transmission lines. In order to
understand the wave phenomena involved, we plan to study the guidance
characteristics by 2D periodic structures to meet some applications.
       In this proposal, we plan to study the guidance characteristics of
two-dimensionally periodic structures. In the first tear of this proposal, we will model
a general two-dimensional periodic structure by a planar surface impedance that is
periodic in two dimensions. The rigorous mode matching will be employed to
construct the dispersion curves rigorously. The new and interesting stop bands will be
clearly explained through this study. In the second year of proposal, we will study the
guidance characteristics of bigrating structure which is composed two crossed
one-dimensionally periodic structures sandwiched by a uniform dielectric layer. Being
the cross of the two periodic layers, the overall structures should be considered as a
two-dimensionally periodic structure. The mode matching technique will be employed
to study the dispersion curves and band gaps. We should expect the existence of many
extra band-gaps which are due to the cross-coupling of TE and TM polarization
surfaces. However, a parametric study will be performed to understand the wave
phenomena in 2D periodic structures. The results from this research will be illustrated
interesting applications.
NSC89-2213-E009-076 (89N301)
-------------------------------------------------------------------------------------------------------

Title:Theoretical and Experimental Study on Two-Dimensionally Periodic Structures
Principal Investigator:Song-Tsueng Peng
Sponsor:National Science Council
Keywords:2D Periodic Structures, PBG, Stop Bands, Band Gaps


   The guiding of waves by periodic structures has long been a subject of continuing
interest in the literature; in the past, however, most of the works had been limited to
the case of one-dimensionally periodic structures. Recently, the class of
two-dimensionally periodic structures that are also known as the photonic band gap
(PBG) structures has attracted considerable attention. For example, two-dimensionally
periodic structures have been demonstrated to be useful for the suppression of surface
waves in the strip-type transmission lines. So far, most of the research are
experimental in nature and the designs are based on the cut-and-trial method.
  The purpose of this work is to establish a solid foundation for the understanding of
wave phenomena in two-dimensionally periodic structures and to explore their
possible applications. We shall include both theoretical and experimental studies, so
that the results obtained can be confidently verified and employed for practical design.
Therefore, this research program is organized into three sub-programs:
1.Guidance characteristics of general two-dimensionally periodic structures.
  This sub-program will carry out a theoretical study on the propagation of wave in
  2D periodic structures of infinite extent, as a rigorous boundary- value problem. Our
  goal is to obtain reliable numerical data in order to establish benchmark results to be
  published in the literature and to form a basis for the other two companion
 sub-programs to develop potential applications in what follows.
2.Theoretical and experimental studies on strip-type transmission line with finite 2D
  periodic structures.
 In this subprogram, we shall setup an experiment to measure the phenomena of band
 gaps with surface wave under different incidence conditions. We shall study the
 propagation characteristics of strip-type transmission lines under the influence of
 finite 2D periodic structures, with particular attention to be focused on the band-gap
 structures of surface waves and strip-type modes.
3.Theoretical and experimental studies on radiation from finite 2D periodic structures.
  In this subprogram, we shall study the radiation characteristic of 2D periodic
  structures and micro-strip line under the influence of finite 2D periodic structure.
  This structure should be also considered as a case of radiation from shielded metal
  plate with finite 2D periodic holes, which are designed for heat sink.
NSC89-2213-E009-074 (89N453)
-------------------------------------------------------------------------------------------------------

Title:On the Study of RS-Code-Embedded Forward Error Correcting Systems (1/3)
Principal Investigator:Yu-De Su
Sponsor:National Science Council
Keywords:Error-Correcting Codes, RS Codes, GMD Decoding, Errors-and-Erasure
               Decoding


      Reed-Solomon (RS) codes belong to the prestigious class of maximum distance
separable (MDS) codes that possess powerful error-correcting capability. Besides the
use in deep outer space communications, RS codes have found numerous
applications, from compact disc player, HDTV, to ADSL and 3G wireless
communication systems. In addition to their burst-error-correcting capability, RS
codes, as a subclass of BCH codes, can enhance their error-control capability by
employing the so-called errors-and-erasures (EE) decoding method. Forney had
presented a generalized minimum distance (GMD) decoding method that can, with a
proper erasure-insertion scheme, achieve the performance of a maximum likelihood
(ML) decoder with much less decoding complexity. However, a complete GMD
decoder still require a complexity several order higher than that of a errors-only (EO)
or a single-pass EE decoder. Recent progress in soft-decision decoding of RS and
BCH codes has greatly shortened this complexity gap thus makes GMD decoding of
RS feasible and ever more attractive. In hostile communication environments such as
those in wideband wireless communication and military communication systems,
soft-decision decoding gain is usually much larger than that in AWGN and whence is
a welcome design alternative in relieving the often-very-tightened link margin.
     The aim of this proposed effort is to study the architectures and performances of
forward error-control systems that employ RS codes. Just like designing any
communication system, the difficulty lies in the receiving end, i.e., the design of an
optimal decoding system. The most critical issues are the derivation of the reliability
function of a received symbol, the erasure-insertion scheme and the corresponding
threshold value. These problems have to do with the modulation and demodulation
schemes and the channel statistics. We shall consider i) linear AWGN, multipath
fading and nonlinear satellite channels, ii) orthogonal and bi-orthogonal signals, iii)
coherent and non-coherent detection algorithms and evaluate the corresponding
performance. As in some cases, RS codes alone can not meet the system error-control
requirement, we shall also those FEC systems that use other error-correcting codes
like ring convolutional codes with CPM or TCM in conjunction with RS codes.
NSC89-2213-E009-088 (89N311)
-------------------------------------------------------------------------------------------------------

Title:On the Design of a Prototype Anti-Jam Satellite CDMA Receiver
Principal Investigator:Yu-De Su
Sponsor:Chung San Institute of Science and Technology
Keywords:CDMA, Nonlinear Equalization, Anti-Jamming, Multi-User Detection


       There are several commercial satellites CDMA system that are either in the
planing stage or being deployed. Rejection of wideband interference caused by other
co-channel user has been a subject of intensive research recently. However, no
investigation of anti-jam method for satellite CDMA systems can be found in the
literature. The nonlinear nature of the satellite channel makes coherent direst sequence
spread spectrum (DS/SS) signals very susceptible to jamming as a jammer can easily
modify the transponder’s operating point and inject PM and AM noise into the desired
signal. The fact that the satellite transponder does not process the on-board processing
capability makes the design of an anti-jam (AJ) receiver even more difficult.
      Our previous investigation had concluded that it is feasible to have a ground
receiver that is capable of simultaneously reducing the satellite nonlinear effect
caused by high power amplifier and suppressing jamming signal. Earlier feasibility
study suggests a receiver structure that is composed of a nonlinear equalizer and
multi-user detector. The proposed effort is a continuation of this study: to refine the
system level analysis and to provide detailed hardware design (based on DSP
firmware) of a programmable AJ software terminal for satellite DS/CDMA system.
Our design requires information about the satellite coordination, its antenna pattern,
coverage area, transponder’s gain control method and high power amplifier
characteristic in addition to the network traffic statistic, access and switching method,
system frequency plan, ground antenna gain and network structure.
      As previous study concentrated on interference rejection and nonlinear
equalization, to build a prototype system we still have deal with other essential
functions of CDMA receiver, namely, synchronization, gain control and demodulation
(decoding). The proposed terminal shall have an access receiving options. Three types
of jammers shall be considered, namely, partial time pulsed jammer, continuous wave
interference and follower jammer.
I89003 (88.07.01-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:Decoding Algorithms for Turbo Codes in 3G Mobile Communication Systems
Principal Investigator:Yu-De Su
Sponsor:ITRI
Keywords:Wireless Communications, Turbo Code, MAP, SOVA


       Since its first appearance six years ago turbo codes have captured the attention
and stimulated researches in many fronts. Turbo codes have very powerful
error-correcting capability at low SNR’s but require decoding complexity and delay
higher than those of conventional convolutional codes. The consensus is that they are
more suitable for those communication mediums that do not have low latency
requirement such as data or image. This was confirmed by the fact that recent
submitted proposals to the ITU for the third-generation (3G) radio transmission
technology all specify that various turbo codes be included for data transmission
mode.
      The purpose of the proposed effort is to study issues related to the design of a
turbo code decoder. More specifically, we intend to i) develop decoding algorithms
with reduced complexity, ii) find appropriate criterions for early decoding iteration
termination, iii) derive optimal and suboptimal decoding metrics for fading multipath
channels, iv) exploit the relationship between RAKE combining method and extrinsic
information generation and v) examine the influences of the above system design
considerations. Furthermore, the interplay between decoder and multiuser detection
shall be examined as well.
C89067 (88.08.01-89.07.31)
-------------------------------------------------------------------------------------------------------

Title : A Novel Three-Dimensional Scattering Model of Radio Propagation in
       Microcellular Urban Environment
Principal Investigator:Jenn- Hwan Tarng
Sponsor:National Science Council
Keywords:Radio Channel Modeling, Microcellular Measurement, Scattering Cross
               Section and Ray-Tracing Technique

     This work will develop a novel three-dimensional scattering model to predict
the path loss and the envelope fading of radio propagation along urban streets in
microcellular environment. For purpose of applications, the analytic scattering
model is combined with a patched-wall model that can describe the reflecting
boundaries more exact. The scattering field due to each patch is evaluated by
computing the scattering cross-action matrix with the theory of physical optics.
With the comparison between the scattering model and the site-specific ray-tracing
model, propagation mechanisms of 1.7~1.9 GHz radio wave along urban streets will
be more clear. Compare the predicted path loss and fading characteristics with the
measured one at 1.7~1.9 GHz will demonstrate the effectiveness of the scattering
model.
NSC89-2213-E009-048 (89N282)
-------------------------------------------------------------------------------------------------------

Title:UHF Radio Channel Modeling and Spatial Signature Analysis(I)
Principal Investigator:Jenn- Hwan Tarng
Sponsor:Chunghwa Telecom Laboratories
Keywords:Vector Channels, Propagation Models, Field Strength Measurement


       To construct the platform of smart antenna systems, it needs to understand the
characteristics of angle-of-arrival, angle spreading and field strength distribution of
site-specific vector channels. In this project the vector channel is modeled by using
electromagnetic theories and numerical methods. The model will be employed to
investigate the mechanisms of 1.8-2 GHz radio propagation in outdoor environment.
The measured data in outdoor will be collected and used to validate the model. In
this year, a three dimensional model for campus environment (rural area) and a
two-dimensional model for urban environment will be developed. Some numerical
examples are used to characterize the vector channels in various environments and
these eamples can also validate our developed algorithms applied for AOS estimation
and adaptive beamforming
C89076 (88.08.01-90.01.31)
-------------------------------------------------------------------------------------------------------

Title:A Study of Spectrum Management and Spectrum Planning in Taiwan
Principal Investigator:Jenn- Hwan Tarng

Sponsor:Ministry of Transportation and Communication

Keywords:Spectrum Management System, Spectrum Planning, Spectrum
                 Reallocation

      The Ministry of Transportation and Communicatio is the spectrum management
authority in Taiwan. In order to make spectrum management effective and systematic,
there must be well defined spectrum management policy, well coordinated
organization and mechanism.
        This research shall reference the spectrum management policies of foreign
countries, and propose to DGT a new organizational and hierarchical structure of
spectrum management, as well a long term spectrum allocation plan.
A89026 (88.11.16-89.11.15)
-------------------------------------------------------------------------------------------------------

Title:Field Testing & Analysis of DTV Terrestrial Broadcasting
Principal Investigator:Jenn- Hwan Tarng

Sponsor:Ministry of Transportation and Communication

Keywords : DTV Field Test, The Effects of Co-Channel or Adjacent-Channel
                Interference, Channel Assignment, EMC


       A national program to build up a DTV station will be finished at the end of this
year and it will also start to broadcast some test programs. To help the DTV service
growing strong in Taiwan, DGT has completed the first phase of DTV field test to
clarify some engineering issues, such as radio coverage, transmitting power of the
base station, multipath fading effect, and propagation characteristics difference
between VHF and UHF channels. In this project, the second phase, the goal is to
investigate the effects of co-channel or adjacent-channel interference on the received
signal, and to optimize the channel assignment for DTV channels. With the help of
the test results like SER, field strength distribution, and interference protection ratio,
the interim rules to regulate the operation of terrestrial broadcasting stations will be
solidified. The measurement or test procedures of DTV signal in field will also be
determined in the project after going through and detail field measurement and
analyses. These results may lay a solid foundation in promotion DTV services in
our country.
A89025 (88.11.02-89.12.31)
-------------------------------------------------------------------------------------------------------

Title:Moving Mircoware Hybrid Integrated Circuit Assembly Technology Toward
       Millimeter-Ware Regime
Principal Investigator:Ching-Kuang Tzuang
Sponsor:National Science Council
Keywords : Packaged Transistor, Hybrid                        Microwave        Assembly,       Hybrid
                   Millimeter-Wave Assembly, Millimeter-Wave PCB Hybrid Circuit,
                   Millimeter-Wave PCB Hybrid Module


      The advent of high-performance millimeter-wave packaged transistor has been a
reality very recently. This low-cost, high-volume approach for packaging transistors
not only pushes the operating frequency of the discrete transistor to millimeter-wave
regime, but renders very cost-effective method for the printed-circuit board (PCB)
realization of modules and systems at millimeter-wave or upper microwave
frequencies.
       Two candidate circuits are planned for fulfilling the purpose of the feasibility
studies of incorporating the packaged transistors for millimeter-wave module designs.
The first is an oscillator built strictly by soldering iron and typical photolithography
technique. The oscillator is improved upon the internal research carried out at Chiao
Tung University, showing an impressive 20 GHz oscillator using the tools available
from any electronic bench. In the first year of the program the high-performance DRO
(dielectric resonator oscillator) will be developed at K- and Ka-bands. In the second
year the attention will focus on the PCB realization of the traveling-wave amplifier
(TWA) with appropriate noise and gain performances for use in a TR ( transmitting
and receiving ) module currently being deployed at Chiao Tung University for
millimeter-wave vision scanning application. The TWA was most often realized by
purely monolithic form in the past. This program will demonstrate the applicability of
PCB realization using discrete packaged transistors which normally occupy fairly
large area compared with the wavelengths, thus opening up the research into this
domain. At the third year, both oscillator and TWA will be tailored to fit into the TR
module system, making a portable millimeter-wave vision system a reality for
practical applications..
NSC89-2213-E009-063 (89N476)
-------------------------------------------------------------------------------------------------------

Title:Quasi-Optical Millimeter-Wave Vision
Principal Investigator:Ching-Kuang Tzuang
Sponsor:National Science Council
Keywords : Millimeter-Wave Vision (MMV), Leaky-Modes, Antenna
                Arrays,        Power       Combiner,          Dielectric        Lens,       Display
                Apparatus


     An advanced millimeter-wave vision (MMV) technology
employing active leaky-modes antenna arrays is proposed. The
millimeter-wave vision (MMV) is a lens system, consisting of
quasi-optical beam -forming power combiner, dielectric lens, active
scanning array receiver, mechanica l scanner, signal processing unit and
display apparatus.
     The core technology resides in the following researches headed and
conducted by various professors:
(1) Baseline    mm-wave     RF     front -end  technology for     MMV
    (Ching-Kuang C. Tzuang,NCTU)
(2) New MM uniplanar RF receiver and source (Chi -Yang Chang,
    NCTU)
(3) MM-waves imaging array design (Yu -De Lin, NCTU)


    This proposal aims to deliver a Ka -band MMV system, capable of
displaying real -time image at the rate of 5 frames/sec and with
resolution of approximatel y 10 0 by 60 pixels/frame. The MMV grouped
efforts require three years to complete. The impact of MMV on the
technology development of so -called wireless communication is
enormous in at least three major areas of interests, namel y, (1) active
integrated antenna array design and manufacture, (2) applied
microwave field theory and (3) IF signal processing. The use of
MM-waves band allows very wide spectrum prohibited in microwave
regime; hence a variet y of modulation schemes and anti -jamming
techniques can be expe rimented in the advanced MMV system. We
present a proposal that encompasses a dual -use technology leading this
nation to the next century competing worldwide for advanced wireless
communication technology development.
NSC89-2213-E009-070 (89N477)
-------------------------------------------------------------------------------------------------------

Title:Baseline MM-Wave RF Front-End Technology for MMV
Principal Investigator:Ching-Kuang Tzuang
Sponsor:National Science Council
Keywords : Active-Integrated Leaky-Mode Antenna, Microstrip, Uniplanar
                  Technology,      Transmission-Type          Injection-Locked,       Quasi-Optical
                  Power Combining, Harmonic-Balance (HB) Analysis


      This proposal describes the basic research carried out to develop a baseline
leaky-modes active-integrated antenna (AIA) technology which originates from an
extensive research of a X-band microwave source module employing the leaky-modes
concept.
      The novel active antenna source module utilizes a microstrip as the radiating
element while adopting uniplanar technology for the active circuit design. The
microstrip is operated in the higher order odd modes, which are leaky modes and can
be efficiently excited by a proximity-coupled center-fed slotline on the same surface
of the uniplanar microwave-integrated circuit. The measured performance of an
X-band transmission-type injection-locked active integrated antenna source module
demonstrated that such approach was suitable for a linear array integration for
quasi-optical power combining. The harmonic-balance (HB) analyses of the proposed
active-integrated antenna agree with the measurements in both free-running frequency
and power level. The measured radiation patterns of the active-integrated antenna also
agree well with the theoretical predictions.
       The high antenna efficiency of greater than 75 % has been experimentally
verified for frequencies up to 26 GHz, revealing great success of the leaky-modes AIA
concept. By proper choice of structural parameters, material constants and novel AIA
configuration, the leaky-modes AIA is expected to work well at millimeter-waves as a
baseline technology, fulfilling the urgent needs of the RF front-ends of the MMV
(millimeter-waves vision) system.
NSC89-2213-E009-071 (89N478)
-------------------------------------------------------------------------------------------------------

Title:The Keyword SPOTTING System Using Decision Tree Clustering
Principal Investigator:Yih-Ru Wang
Sponsor:National Science Council
Keywords:Decision Tree, Keyword Spotting, Relative Entropy, Discriminative
         Training


       In this project, a new idea of selecting keyword models and filler models for
keyword spotting based on the decision tree clustering method will be studied. It first
constructs a decision tree with all leaf nodes representing context-dependent models
of phone-like units (PLU). In the model construction process, the node spitting
procedure will be sequentially applied to divide coarser parent nodes into finer leaf
nodes. We can therefore choose models on leaf nodes to form keywords, and take
some models on internal nodes as filler models. This will make the recognition score
of the correct keyword model greater than the corresponding filler model if the input
utterance is a keyword. A systematic method is needed to choose proper internal
nodes to form filler models in order to minimize Type I and Type II errors. This will
be intensively studied in this project. A method will be tried first. It first calculates the
distance of each model-pair using the relative entropy measure and then chooses an
initial set of filler models using these distance measures. It then defines a loss
function and applies the MCE/GPD algorithm to fine-tune the keyword and filler
models for minimizing the keyword recognition rate and Type I and II error rates
simultaneously.
NSC89-2213-E009-119 (89N333)
-------------------------------------------------------------------------------------------------------

Title : Header-Replacement Technique in All-Optical DWDM Packet-Switched
        Networks
Principal Investigator:Winston I. Way
Sponsor:National Science Council
Keywords : All-Optical Packet-Switched Network, Header Replacement, Low
                 Latency, SCM


       The objective of this research project is to demonstrate a novel method for
header replacement in an all-optical dense-wavelength-division-multiplexing
(DWDM) packet-switched network. This method should facilitate the upgrade of
data payload speed in the future, while processing the header with accessible
electronic techniques. We expect that the proposed method can keep the total
latency in each network-processing node less than 1
prototypes of transmitter and network nodes, we will also analyze the maximum
distance transmission that can be achieved by using this method.
NSC89-2215-E009-015 (89N350)
-------------------------------------------------------------------------------------------------------

Title:Loop Experiment for Testing Long-Distance(>1,00 km)DWDM Subcarrier
       Multiplexed Lightwave Video and Telecommunication Systems
Principal Investigator:Winston I Way
Sponsor:National Science Council
Keywords : Subcarrier-Multiplexed Lightwave System, M-QAM Video,
                    Long-Distance, Loop Experiment


       This project is a continuation of last year’s research on long-distance subcarrier
multiplexed (SCM) systems for multi-channel digital video distributions. In addition,
we plan to extend the current research results to the transportation of high data rate
(e.g., 10 Gbps) telecommunication signals. In last year’s long-distance SCM system
research, we have obtained very thorough understanding of the nonlinear distortions
and CNR degradations caused by (1) self-phase modulation, (2) stimulated Brillouin
scattering, (3) double Rayleigh backscattering, (4) Stimulated Raman scattering, (5)
cross phase modulation, (6) linear fiber dispersion, and (7) cascaded EDFA noise.
From those analytical and computational results, we found that it is quite feasible to
transport M-QAM video signals over a distance more than 1000 km. Therefore, in
this year, we plan to actually implement a circulating loop to prove what we have
predicted. We will also use this SCM system circulating loop, the first in the world, to
try two-wavelength DWDM experiment and examine the effects of (4) and (5) above.
NSC89-2215-E009-014 (89N456)
-------------------------------------------------------------------------------------------------------

Title:The Feasibility Study of Transporting CDMA/TDMA Wireless Signals in
      Passive Optical Networks and HFC Networks(Ⅱ)
Principal Investigator:Winston I Way
Sponsor:Chunghwa Telecom Laboratories
Keywords:CDMA/TDMA, Wireless, PON, HFC


      In This second-year project, we will demonstrate a new system
application--combining fiber-to-the-building (FTTB) and fiber-in-the-building (FITB)
networks. The former was an existing infrastructure, considering the massive FITB
optical fiber cables already deployed by Chung-Hwa Telecom. The latter is
composed of two types of optical fiber infrastructure. The first one is local area
network in business buildings, and the other is direct-broadcast satellite
(DBS)-distribution network in residential and business buildings.                            We will
experimentally demonstrate the feasibility of integrating FTTB and FITB
infrastructure, which could potentially increase the revenue of Chung-Hwa Telecom.
C89136 (88.11.01-89.10.31)
-------------------------------------------------------------------------------------------------------

Title:Applications of FDTD in the Analysis of EMC Problems in Multilayer PCBs
Principal Investigator:Lin-Kun Wu
Sponsor:National Science Council
Keywords:FDTD, Conducted and Radiated Emission, Multilayer PCBs


     Development of FDTD (Finite-Difference Time-Domain) method as an
integrated tool for the analysis of conducted and radiated emission problems
associated with multilayer PCBs is proposed. Properly designed computation
experiments will be conducted to investigate the efficacies associated with 3 sets of
empirical EMC design rule that are commonly followed in industry. In addition,
possibilities and appropriate methods to interface the core FDTD program with layout
and device models commonly used in commercial EDA software packages, and to
implement it in the form of parallel algorithm suitable for running on multiple-PC
platforms, will also be investigated.
NSC89-2213-E009-049 (89N283)
-------------------------------------------------------------------------------------------------------

Title:Design of Gigabit MAC and PHY Stack
Principal Investigator:Wen-Rong Wu
Sponsor:ITRI
Keywords : Ethernet, IEEE 802.3 Modulation And Coding, Decoding, Echo
                 Cancellation, Near-End Cross Talk Cancellation, Equalization, Optimal
                 System Parameter, Real-Time Implementation


       With million connections, Etherent may be the most popular LAN interface in
the world The key to the popularity of Ethernet is not that one size fits all but those
common protocols available for a wide range of applications, and the ability to
evolvewith the changing of the market requirement. Originally, Ethernet is
standardized and deployed for 10Mbps, however,it has been considered as a
high-speed network . IEE E 802.3 committee has proposed a standard for gigabit
Ethernet over Category-5 cable.This project considers the design issues related the
gigabit Eethernet 1000Bas-T twisted pair transceiver. Specifically, we will investigate
the following topics (1) modulation and coding, (2) decoding, (3) echo cancellation ,
(4) near-end cross talk cancellation ,(5)equalization . we will evaluate the system
performance using software simulations. Then , we will experimentally determine the
optimal system parameters.
This will be of great value for hardware implementation. Finally ,we will develop
efficient algorithms improving the system performance as well as facilitating
real-time implementation.
C89096 (88.07.01-89.06.30)
-------------------------------------------------------------------------------------------------------

				
DOCUMENT INFO