Enhancement of Throughput for Multi Hop WPAN’s Using UWB - OFDM Physical layer

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(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 5, May 2011

Enhancement of Throughput for Multi Hop WPAN’s
using UWB- OFDM Physical Layer
Ch. Subrahmanyam K. Chennakesava Reddy Syed Abdul Sattar
Department of ECE Department of ECE Department of ECE
Scient Institute of Technology TKR College of Engg. &Tech. Royal Institute of Tech. & Science
Hyderabad, India Hyderabad, India Hyderabad, India
e-mail: subbunvl@yahoo.com e-mail: kesavary@hotmail.com Email: syedabdulsattar1965@gmail.com

Abstract— One of the most significant determinants extensive usage of cutting edge WPAN networks (up to 480
for the UWB (Ultra Wide Band) based substitutive Mbps) grounding on a UWB physical layer application. The
physical layer for WPANS (Wireless Personal Area special interest group (SIG) from IEEE have structured for this
Networks) is MB – OFDM (Multiband Orthogonal high- rate WPANS, which is popularly known as IEEE
Frequency Division Multiplexing). This paper deals in the 802.15.3.
manipulation outcomes for Multi-Hop WPAN depending
upon the UWB - OFDM physical layer are exhibited. We begin with the thought of Multi Hop Wireless Personal
However, the spectrum radius of MB-OFDM UWB Area Network (WPAN) in this paper, then the confrontations
machines is quite minimal, and single-hop transmissions of the Multi Hop WPANS, and later the reflections of Multi
may not be sufficient for WPANs functionalizing at huge- Hop WPANS for the performance assessments like End- to-
data-rates. Therefore, a multi-hop provisional WPAN End delay, Packet Failure rate calculations for both the data
machine is appropriated at this juncture so as to maximize rates of 200 Mbps and 480 Mbps.
the coverage of UWB radio. Performance of the entire
machine is achieved to determine if the Quality-of-Service
conditions can, now even, be sustained when an IEEE
802.15.3 TDMA MAC stratum is used in multi-hop II. MULTI HOP WPAN’S
correspondence situations. Simulation outputs for Multi
Hop WPAN standing on the UWB - OFDM physical layer Mobile multi-hop Adhoc networks (MANETs) are assortments
are reproduced in this paper. In this mode of functioning, of mobile nodes of bridges linked together over a wireless
the transmitting machines for the data rates of 200 Mbps, viaduct. These nodes can freely and actively self-monitor into
480 Mbps are used because these two are the directives for approximate and temporary expedient network analysis sites.
the highest compulsion rate and the greatest optional rate In this way, instruments can seamlessly inter-network in areas
respectively. We used both 9mX 9m and 20mX20m where pre-existing communication infrastructure (e.g., disaster
geographical areas for the networks fields for the Multi recovery sites and battlefield environments) is zero. The
Hop scenarios in this simulation model. The critical discreet connectivity concept is not a budding one , but has
functionalities of the Multi Hop WPANS like average End been in existence for the last 30 years in different modes such
– to – End Delay and Packet Failure Rate(PFR) and for all as packet radio network (1972), sustainable adaptive radio
the source – Destination pairs are manipulated and network (1980), Global Mobile information system (early
restricted by employing the Qualnet network simulator. 1990s). Due to their quick and economically less demanding
deployment of Ad hoc wireless networks we observe
Keywords- Multi hop, OFDM, Throughput, UWB, WPAN’s applications for the same in many areas. Defense applications,
associated and spearheaded computing, emergency operations,
I. INTRODUCTION wireless mesh networks, wireless sensor networks, and hybrid
wireless network architectures are some of the areas its
At this juncture, there is a huge requirement for wireless applications. Conventionally, logical networks have been the
communication systems that could be monitored at high only correspondence networking practice that accepted the ad
amount of data rates over a very less distance communications hoc paradigm. The thumb-rule behind provisional networking
so as to attain the modern advances in electronic gadgets is that of multi-hop relaying.
(Camcorders, DVD Players, etc). The usage of high - rate
Wireless Personal Area Networks (WPANs) for short In cellular networks, the routing decisions are acceded in a
distances provisional connectivity among electronic gadgets centralized format under the surveillance of base stations. But
and communication devices have paved their way since 2000. in an ad hoc cordless network, both accessing and resource
having been approved from Federal Communications management are operated in a scattered form in which all
Commission (FCC) for the use of Ultra- Wide- Band (UWB) nodes would associate to capacitate communication among the
on the unlicensed band in 3.1 – 10.6 GHz range maximizes the nodes themselves. This calls for each bridge to be more

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intelligible so that it can act both as a data signaling host for network, due to the huge amount of variables taken part, the
transmitting and receiving data, and as a network lane for amplitude of the machine develops significantly, thus
routing packets from other ends. Hence, the mobile paths in materializing logical modeling a considerably arduous task.
possible wireless networks are more confusing and entangled On the side of the machine, simulation methods capacitate the
than that of their correspondents in cellular networks. The exploration of more problematic and realistic phenomena. In
truancy of any central administrator, or control station, makes composite machinery such as multi-hop networks, attentive
the routing process a more complicated one compared to that preference of the system attributes can drive to considerable
found in cellular networks. Multi-network ―hops‖ may be development in function, specifically for time-sensitive
required for one station to interchange information with applications. Focusing on time-sensitive applications, the
another node located elsewhere in the network due to the objective is to examine the performance strategies of multi-
restricted transmission range of a wireless network. In such a hop WPAN systems standing on an OFDM physical layer.
network, each mobile node operates not only as a host but also Compatible system functioning precautions involving end-to-
as a router, forwarding packets for other mobile nodes in the end delay, productivity and packet failure rate realized in
network that may not be within direct wireless transmission various conditions with different choices of system
range of each other. Each node involves in an accessing parameters.
protocol that permits it to search for ―Multi-hop‖ paths
through the network to any other node.
A. Capacity Analysis of a Multi-Hop Network
WPAN is said to be a single-hop network as per the present
IEEE 802.15.3 Strategy. That is, an info packet can be The network productivity or approximate capacity for a multi-
forwarded only from a source address to a destination address, hop network is described in this section. When frequency
and there is no arbitrating node to work as a ―router‖. Using an reuse is not considered, the capacity of multi-hop networks is
UWB - OFDM physical layer practicability for a WPAN, the greatly affected by the average hop count h. Theoretically, if
amount that can be attained is acutely minute, usually less than the network capacity based on peer-to-peer communications is
10 meters. For an assured transmission with minimal packet C , the capacity of multi-hop networks will be C = C/h ,
error progression, a certain concentration of within 4 meters is assuming that the network bandwidth used for routing
usually needed. The benefit with a multi-hop network is messages is multi negligible, and that a high-efficiency
obvious as it can maximise network coverage without scheduling scheme is implemented. If the aggregate packet
increasing either the accessibility strength, or sensitivity of the production rate is r Mbps, the highest number of source-
receiver. The other advantage is that of improved reliability destination pairs that can be supported is L = C /r. When the
through redundancy of route. The ambit of IEEE 802.15.3 number of source-targeted pairs L is max multi over L,
MAC code to provide multi-hop networks calls for attentive packets will be launched due to the existence of a network due
and comprehensive observation. point condition at max.

An example is used to demonstrate why a Multi - hop WPAN The conversion and transformation system being monitored at
is required to provide backup for immense progression 200 Mbps is utilized here to exemplify how the Multi- hop
practical traffic flows. A video conference or home theatre network ability is related to the associated network
system is a trivial practice for use of WPAN based on the strategy and the average hop count. It is known that the
OFDM UWB physical layer. That is, to transmit the attainable productivity for 200 Mbps peer-to-peer transmission
multimedia traffic instead of using cables, the unwired links is about 120 Mbps. If the average hop count is set to h = 3, the
will be used. The frequency range requirements for each capacity of a multi-hop network will be C = 120/3= 40 Mbps,
traffic outflow is about 6 Mbps, the average downtime should theoretically. the maximum number of source-destination =
be less than 90 ms, and the packet Failure rate, less than 8% so 40/6 = 6, if the average packet multi generation rate per link is
as to arrive at the required QoS level. The circuitry region for r = 6 Mbps,. If the packet Generation rate doubles, that can be
a video conference or home theatre system generally ranges supported is L = C /r max multi per link r = 3 Mbps, then the
from 9 m x 9 m to 20 m x 20 m. The indemnity radius for an maximum number of source-destination pairs that can be =
UWB - OFDM regulation is relatively only 3 meters for a data 40/3 = 13. If the average hop count is fixed to backed up is
procession of 200 Mbps and only 7 meters for a info L = C /r h = 4, the max multi capacity of a multi-hop network
progression of 480 Mbps to guarantee a PER of 8%. A single- will be C = 120/4 = 30 Mbps, theoretically. If the multi
hop network structure is inadequate to cover the expected average packet generation rate per link is r = 6 Mbps, then the
network area for these huge amounts of data rates have maximum number of source-destination pairs that can be
retained obvious. If a Multi - hop WPAN frame works well, supported is L = C /r = 30/6 = 5. The maximum number of
then the network coverage area can be perfectly enlarged source-destination pairs that can be backed up is L = C /r =
through the application of arbitrary nodes while monitoring 30/3 = 10. If the max multi average packet generation rate
transmission at the required data rates. The suitability of the per link is r = 3 Mbps. When the max multi number of source-
IEEE 802.15.3 TDMA MAC layer for use with multi-hop estimation pairs L is greater than L, packets will get a break
WPAN systems necessitates to be recognized. In Multi - hop down affected due to the saturation of max network.

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Resultantly, the packet failure rate and the aggregate Table 1. abridges the limitations of system used in the simulations for the
downtime should increase productively. Multi -hop situations recognized in this analysis.

Simulation parameter Value
III. PREVAILING CHALLENGES IN MULTI-HOP NETWORKS Simulation Time 5s
Number of nodes 20
Number of links 2,4,6,8,10
In a multi-hop provisional network, connections correspond Network Area 20mX20m for 200 Mbs
with each other using multi-hop wireless links, and there are 9mX9m for 480 Mbps
no static infrastructure instruments similar to a ground station.
Each connection in the network also plays a role as a router, Node’s coverage radius to 6.9m for 200 Mbps
achieve a PER of 5% 2.95m for 480 Mbps
enrooting data packets for other nodes. One of the prominent Number of Channels 1(Center Frequency = 3.432
hurdles is the structure of active routing protocols that can GHz
efficiently search for routes between two corresponding nodes. Transmission Power -10.3 dBm
Routing is apparently the first methodology to be reconsidered Receiver sensitivity -77.2 dBm for 200 Mbps
-72.6 dBm for 480 dBm
in altering from single-hop to multi-hop implementations [6]. Channel model considered Free space,Shadowing,and
A mobile ad hoc networking (MANET) functioning set has Rayleigh fading
been established within the Internet Engineering Task Force Packet size(application 982 bytes(will be 1024 bytes
(IEFT) to develop a routing framework for IP-based protocols layer) after MAC layer)
Max Network Buffer size 1,00,000 Bytes
in ad hoc networks. Dozens of routing protocols for MANETs
CTA slot Duration Transmission duration of 1024-
have been introduced, some examples including DSDV Byte Packet
(Destination Sequenced Distance Vector), DSR (Dynamic Number of slots per Frame
Source Routing), and AODV (Ad-hoc On-demand Distance for Equal- Weighed Node- 20
Based Scheduling
Vector). However, most simulations and performance
Number of slots per Frame 20,40 for 200 Mbps
affinities of mobile Adhoc network piloting protocols are for On – Demand Link- 30,60 for 480 Mbps
based on a condensed and visionary physical layer model, as Based Scheduling
well as easy performance metrics.
Guard time between slots 1 µs
Intra Frame time 1.875 s
Most of the presently prevailing codes were framed out under
the hypothesis of an UDG (Unit Disk Graph) communication
model, in which signal strength variations due to a realistic
A. SIMULATION RESULTS FOR EQUAL-WEIGHTED
channel are not considered. Without modification, such
NODE-BASED SCHEDULING
routing schemes cannot work well with physical layer
characteristics that are correspondent of more factual
communication channel environments. The equal-weighted node-based scheduling scheme is first
implemented. The packet generation rates are taken to be 128
IV. SIMULATION RESULTS FOR MULTI-HOP WPAN kbps, 3 Mbps and 6 Mbps. Figures 1 and 2 exemplify the
SYSTEMS average delay and the PFR with PGR taken as a parameter
using the equal- weighted scheduling scheme for systems
The simulation results for multi-hop communication system operating at 200 Mbps. Figures 3 and 4 illustrate the average
structuralizing are exhibited, and the assistive performance delay and the PFR with PGR considered a parameter using the
analyses are given in this paper. The transmission systems equal- weighted scheduling scheme for systems being
operating at 200 Mbps and 480 Mbps are simulated in this operated at 480 Mbps.
analysis as they are representatives of the immense mandatory
rate and the immense optional rate, respectively. First, the Each node has the same share of the bandwidth irrespective of
simulation results and function analysis for the equal-weighted whether it has a packet to transmit or not and independent of
node-based scheduling scheme are shown. Then, the how many packets it needs to transmit for equal-weighted
simulation outputs and performance analysis for the on- node-based scheduling. For the total number of network nodes
demand link-based scheduling scheme are given. set to 20, each node can have 120/20 = 6 Mbps of frequency of
the network available for systems being operated at 200 Mbps,
In an unorthodox simulation scheme we applied for Multi – and 180/20 = 9 Mbps of network bandwidth available for
Hop networks are basically depended on the Link formation systems operating at 480 Mbps. If the PGR per link is 6 Mbps,
algorithm because of the existence of direct relationship only 1, or possibly 1.5 traffic currents can be backed up by one
between the Throughput and the scheduling competence. In node in either case. So, there will be collisions, and some of
this imaging task we used the two Link organizing algorithms; the packets will be dropped, if a node is a transmitting node
the first is Equal-Weighted Node-Based Scheduling and the for one traffic progression and a forwarding node for another
second, On-Demand Link-Based Scheduling. traffic stream. This situation occurs rarely, and sometimes
there are number of traffic currents which need to be

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transmitted by one node at the same time. Hence, the system
may work well with high probability only when the number of
source- destination pairs is very small. When there are not
more than 2 active links when the PGR equals 6 Mbps for
systems operating at either 200 Mbps, or 480 Mbps only, the
simulation results show that the performance measures are
acceptable. When the number of source-destination pairs L is
greater than 2, both the PFR and the average delay increase
logically. Similarly, if the PGR per link is 3 Mbps, only 2 or 3
traffic streams can be transmitted from one node at the same
time in either case. The situation is better than that for a PGR
equal to 6 Mbps, but the capacity available for each node is
still not enough. It can be observed that a maximum of 4
Figure 2.: PFR vs. Number of Source-Destination Pairs With Equal-Weighted
active links can be supported. When L > 4, both the PFR and Scheduling for Transmission Systems Operating at 200 Mbps.
the delay maximizes dramatically. The maximum numbers of
source-destination pairs that can be supported are less than the
theoretically predicted capacities that were presented in
Section II.A for machines being operated at either 200 Mbps,
or 480 Mbps. The efficiency of allotment is less, and the
system bandwidth is wasted. For a PGR equal to 128 kbps,
there are over 50 traffic currents that can be backed by any one
node at the same time for systems operating at either 200
Mbps, or 480 Mbps. when the PGR is 128 kbps, it can be
recorded that the PFR (<8%) and the delay (about 5ms) both
meet the QoS requirements for real-time applications even for
10 active links. The Equal - weighted scheduling scheme only
works well when either the packet generation rate is low, or
there is only a very small number of active links. However, a
UWB-based WPAN system is structured for high-data rate
inter media progression, and hence, QoS requirements have to Figure 3.: Average Delay vs. Number of Source-Destination Pairs With Equal-
Weighted Scheduling for Transmission Systems Operating at 480 Mbps
be met. The simple equal- weighted node-based scheduling
cannot execute well in this kind of condition. For huge amount
of info speeds, the on-demand scheduling scheme has to be
considered.

Figure 4.: PFR vs. Number of Source-Destination Pairs With Equal-Weighted
Scheduling for Transmission Systems Operating at 480 Mbps

B. SIMULATION RESULTS FOR ON-DEMAND LINK-
BASED SCHEDULING
Figure 1.: Average Delay vs. Number of Source-Destination Pairs
With Equal- Weighted Scheduling for Transmission Systems For the on-demand link-based scheduling scheme, the packet
Operating at 200 Mbps generation rates are absorbed to be 3 Mbps and 6 Mbps. A
value for PGR of 128 Kbps is not accepted here for the on-
demand link- based scheduling scheme, provided that the
equal-weighted scheduling can function perfectly for low data
rates.

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As the criteria of using the on-demand link-based scheduling
scheme for systems operating at 200 Mbps, Figures 5 and 6
explain the aggregate delay and the PFR with PGR,
respectively. It can be marked that saturation of the network is
reached when there are more than 6 dynamic connections for a
PGR similar to 6 Mbps. Both the PFR (<7%) and the delay (<
40 ms) are appropriated for real-time applications before
network due-point happens. Another analysis is that both the
PFR (< 7%) and the delay (< 40 ms) are feasible even for the
case of 10 dynamic links when the PGR is 3 Mbps per link.

These simulation yields for systems operating at 200 Mbps
match the theoretically assumed capacities that were shown in Figure 5.: Average Delay vs. Number of Source-Destination Pairs With
Section II.A. That is, a total of 6 links can be reinforced when On-Demand Scheduling for Transmission Systems Operating at 200 Mbps
the PGR is equal to 6 Mbps and 12 links can be supported
when the PGR is equal to 3 Mbps. Figures 7 and 8 exemplify
the average delay and the PFR, respectively, using the needed
scheduling scheme for systems being functioned at 480 Mbps.
It can be considered that saturation of the network is attuned
when there are more than 8 active links for a PGR equal to 6
Mbps. Both the PFR (< 7%) and the delay (< 10 ms) remain
reasonable before network saturation occurs.

Another observation is that both the PFR (< 7%) and the delay
(< 10 ms) are acceptable even for the case of 10 active links
when the PGR is 3 Mbps per link. The simulation results
attained for networks functionalizing at 480 Mbps match the
theoretically and impractically assumed capacities that were
Figure 6.: PFR vs. Number of Source-Destination Pairs With
produced in Section II.A. That is, 8 links can be upheld when
On-Demand Scheduling for Transmission Systems Operating at 200 Mbps
the PGR is equal to 6 Mbps and 16 links can be supported
when the PGR is equal to 3 Mbps.

When the PGR is 3 Mbps per link, this will also be examined
that both the PFR and the delay reach the QoS requirements
for real-time applications even for 10 active links. With the
same network buffer size, the PFR is almost the same when
the PGR is equal to 6 Mbps and when the PGR is equal to 3
Mbps. The delay when the PGR is same as to 3 Mbps which
is slightly smaller than that when the PGR is equal to 6 Mbps.
This is feasible since there will be more adjoining deferment
associated with the higher data rate.

The simulation outputs described above for machines being
monitored at both 200 Mbps and 480 Mbps match the capacity
analysis for a multi-hop network exhibited in Section II.A.
Hence, it can be examined that the efficiency in allotment is Figure 7.: Average Delay vs. Number of Source-Destination Pairs With On-
Demand Scheduling for Transmission Systems Operating at 480 Mbps
comparatively greater for the required scheduling scheme, and
the network bandwidth can be utilized more efficiently than in
the case of the equal-weighted scheduling scheme. It can be III CONCLUSIONS
summarized that this UWB-based multi-hop WPAN system
performs well when the on-demand link- based scheduling is Based on the simulation results attained and performance
used along with the proper routing protocol. analyses described in the previous section, conclusions can be
drawn. The equal-weighted node-based allotting scheme does
not function well for high-data rate applications. That is, the

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Propagation,‖ IEEE Journal on Selected Areas in
Communications , Vol. 11, No. 7, pp. 967-978, September
1993.
[7] L. Maret, I. Siaud and Y. Kamiya, ―Ultra WideBand PHY
Layer MBOA Performance and Sensitivity to Multipath
Channels (IST Magnet Project),‖ http://www.ist-magnet.org/.
[8] MultiBand OFDM Alliance, ―Multi-Band OFDM Physical
Layer Proposal for IEEE 802.15 Task Group 3a,‖ September
14, 2004, http://www.wimedia.org/.
[9] H. Xu and A. Ganz, ―A Radio Resource Control Method in
UWB Protocol Design,‖ Military Communications
Conference, Vol. 2, pp. 886-891, October 2003.
[10] S. Datta, I. Seskar and M. Demirhan, ―Ad-hoc Extensions
to the 802.15.3 MAC Protocol,‖ Proceedings of the Sixth
Figure 8.: PFR vs. Number of Source-Destination Pairs With On-Demand
IEEE International Symposium on a World of Wireless
Scheduling for Transmission Systems Operating at 480 Mbps.
Mobile and Multimedia Networks (WoWMoM’05) ,
Taormina, Giardini Naxos, pp. 293-298, June 2005.
scheduling efficiency is low and much of the available [11] A. Rangnekar and K. Sivalingam, ―Multiple Channel
network frequency had been wasted. When either the data rate Scheduling in UWB Based IEEE 802.15.3 Networks,‖
is very low, or there are only a very small number of active Proceedings of the First International Conference on
links, this scheduling scheme only executes well since the Broadband Networks (BROADNETs) , San Jose, CA, pp. 406-
network bandwidth is not utilized efficiently. 415, October 2004.
[12] H. Fattah and C. Leung, ―An Overview of Scheduling
The On - Demand link-based scheduling scheme can perform Algorithms in Wireless Multimedia Networks,‖ IEEE
well for the UWB-based multi-hop WPAN system taken into Wireless Communications Magazine, pp. 76-83, October
view here. That is, the scheduling efficiency is high, and the 2002.
network bandwidth is utilized efficiently. Thus, the IEEE [13] I. Stojmenovic, A. Nayak and J. Kuruvila, ―Design
802.15.3 TDMA MAC layer with the accurate scheduling and Guidelines for Routing Protocols in Ad Hoc and Sensor
routing schemes perform well in the context of multi-hop Networks with a Realistic Physical Layer,‖ IEEE
networks. Multi-hop WPANs based on a realistic OFDM Communications Magazine, pp. 101-106, March 2005.
UWB physical layer can be a suitable method to improvise [14] H. Gao and D. G. Daut, ―Position-Based Greedy Stateless
the network coverage while backing up huge amount of data Routing for Multihop WPANs Based on a Realistic UWB
rate multimedia traffic. Physical Layer,‖ Second IEEE International Conference on
Wireless Communications, Networking, and Mobile
Computing(WiCOM) , Wuhan, P. R. China, September 2006.
[15] D. Couto, D. Aguayo, J. Bricket and R. Morris, ―A High-
REFERENCES
Throughput Path Metric for Multi-Hop Wireless Routing,‖
[1] R. Bruno, M. Conti and E. Gregori, ―Mesh Networks: International Conference on Mobile Computing and
Commodity Multihop Ad Hoc Networks,‖ IEEE Networking (MobiCom) , San Diego, CA, pp. 134-146,
Communications Magazine, pp. 123-131, March 2005. September 2003.
[2] C. S. Murthy and B. S. Manoj, Ad Hoc Wireless [16] H. Tsai, N. Wisitpongphan and O. K. Tonguz, ―Link-
Networks: Architecture and Protocols, Prentice-Hall, NJ, Quality Aware Ad Hoc On- Demand Distance Vector Routing
2004. Protocol,‖ First International Symposium on Wireless
[3] F. Eshghi, A. K. Elhakeem and Y. R. Shayan, Pervasive Computing , Phuket, Thailand, January 2006.
―Performance Evaluation of Multihop Ad Hoc WLANs,‖ [17] L. Qin and T. Kunz, ―On-demand Routing in MANETs:
IEEE Communications Magazine, pp. 107-115, March 2005. The Impact of a Realistic Physical Layer Model,‖ Proc.
[4] A. F. Molisch, J. R. Foerster and M. Pendergrass, Second International Conference on Ad Hoc, Mobile and
―Channel Models for Wireless Networks, Montreal, Canada, pp. 37-48, October
Ultrawideband Personal Area Network,‖ IEEE Wireless 2003.
Communications Magazine, Vol. 10, pp. 14-21, December [18] S. Lee, B. Bhattacharjee and S. Banerjee, ―Efficient
2003. Geographic Routing in Multihop Wireless Networks,‖
[5] M. D. Benedetto and G. Giancola, Understanding Ultra International Symposium on Mobile Ad Hoc Networking and
Wide Band Radio Computing (MobiHoc) , Urbana-Champaign, IL, pp. 230-241,
Fundamentals, Prentice-Hall, NJ, 2004. May 2005.
[6] A. Saleh and R. Valenzuela, ―A Statistical Model for
Indoor Multipath

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AUTHORS PROFILE

Prof. Ch. Subrahmanyam presently working as a Dr. Syed Abdul Sattar, presently working as a Dean of
Professor & Head, Department of ECE at Scient Academics & Professor of ECE department, RITS,
Institute of technology, Hyderabad. He has completed Chevella, Hyderabad. He has completed his B.E. in
his B.E. in 1995 from Andhra University, A. P. India, ECE in 1990 from Marathwada university Aurangabad,
and M. Tech. from JNTU Hyderabad, in 2002, and M.S. India, M. Tech. In DSCE from JNTU Hyderabad,
Pursuing his Ph.D. from JNTU Hyderabad, A. P. India in 2002, and Pursued his first Ph.D. from Golden state
with ECE in Wireless communications. He has about 15 University USA, with Computer Science in 2004, and
years of experience in teaching and industry together, he is having second Ph.D. from JNTU Hyderabad, A. P. India with
publications in International Journals and Conferences. He has guided many ECE in 2007. His area of specialization is wireless
M. Tech and B. Tech. Projects. He is a life member of ISTE, India. communications and image Processing. He has about 21years of experience in
teaching and industry together and recipient of national award as an
Engineering Scientist of the year 2006 by NESA New Delhi, India. He has
Dr. K. Chennakeshava Reddy, Presently working as about 73 publications in International and National Journals and conferences.
Principal & Professor of ECE at TKR College of Presently he is guiding more than 15 research scholars in ECE and Computer
Engineering. He has completed his B.E. in 1973 and M. Science from different Universities. He is a member of Board of studies for a
Tech. in1976 from REC Warangal, A.P. India, and central university and reviewer/editorial member/chief editor for national and
Ph.D. in 2001 from JNTU Hyderabad. He has worked International journals.
in various positions starting from lecturer to Director of
Evaluation in JNT University, Hyderabad, A. P. India.
He has about 70 publications in international and National journals and
Conferences and he has successfully guided 4 Ph.Ds and many are under
progress. He is a member of various technical Associations.

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