WiFi Technology

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Telecom Regulatory Authority
  Technical Affairs & Technology Sector




              WiFi
           Technology




       Technology Tracking Department

                 July, 2003
WiFi Technology                                                   1


Preface

Wireless communication is becoming the standard in the business world. Remote
wireless Internet connections and wireless computer networks are appearing on the
scene and will dramatically impact the way business does in the future. It has truly
become a wireless world.
In the past five years, Wi-Fi (also known as “802.11b”, “802.11g” and “802.11a”) has
emerged as the dominant standard for wireless LANs (WLANS) worldwide. Anyone
can set up a Wi-Fi network and cover an area of typically 100-500 feet with Internet
access hundreds of times faster than a modem connection. It has become the “TCP/IP
of wireless”, a single networking standard for all developers, equipment
manufacturers, service providers and users. As with TCP/IP, any innovation in Wi-Fi
benefits everyone else in the Wi-Fi community.

This study aims to give an overview over WLANs from different point of views.
For example, Part-1 handles the technical aspects of WLANs, including its network
topology, radio topology, brief explanation of the IEEE 802.11 standards and securing
the WLAN, that’s plus comparing WiFi with other technologies, for example 3G and
Bluetooth.
Part-2 discusses WiFi as a Market/Business model. This part presents some case
studies for existing models that are already used in USA and Europe. This part must
be taken into consideration, when establishing a well-defined WiFi market in Egypt.
Part-3 discusses the regulatory aspects of WiFi. This part takes an overlook over the
regulators of the advanced countries and how they deal with introducing WiFi to the
market.




Technology Tracking Dept.                                                   TRA
WiFi Technology                                        2


Index

A- Part─1 ……. Technical aspects of WLANs

      1.1. Introduction………………………………………………..4

      1.2. Wi-Fi Network Topology………………………………….6

            1.2.1. Network Components

            1.2.2. Designing the WLAN Layout

            1.2.3. WLAN Network Implementation Consideration

      1.3. Wi-Fi Radio Topology……………………………………14

            1.3.1. IEEE 802.11 PHY Layer

            1.3.2. IEEE 802.11 MAC Layer

            1.3.3. IEEE 802.11 Network Layer

      1.4. IEEE 802.11 standards…………………………………...20

      1.5. Wi-Fi Security…………………………………………….24

      1.6. Wi-Fi Vs Other technologies…………………………….28

            1.6.1. WiFi and Bluetooth

            1.6.2. WiFi and 3G

B- Part─2 ……. Marketing Study for WLANs.

      2.1 . Roadmap for WiFi………………………………………34

      2.2. Business Model for WiFi. ……………………………...36

C- Part─3 ……. Regulatory aspects of WLANs




Technology Tracking Dept.                                      TRA
WiFi Technology             3




Technology Tracking Dept.       TRA
WiFi Technology                                                    4


1.1. Introduction.

The Market for wireless communication has grown rapidly since the introduction of
802.11b wireless local area networking (WLAN) standards, which offer performance
more nearly comparable to that of Ethernet.
WLAN (or WiFi) was created specifically to operate as a wireless Ethernet. It is an
open-standard technology that enables wireless connectivity between equipments and
local area networks. Public access WLAN services are designed to deliver LAN
services over short distances, typically 50 to 150 meters. In these cases, WLANs are
connected to a local database, and give the end user access through a kiosk or portable
device.
Internet access through public WLANs is a new and very hot trend, providing many
benefits and conveniences over other types of mobile Internet access.
First, performance is 50 to 200 times faster than dial-up Internet connections or
cellular data access. Second, users do not have to worry about cords, wires or sharing
an access point, such as a phone jack.

A global directory that would provide users with a search engine to locate the closest
access point. Even without the directory, WLAN devices make it very easy to
connect. Most WLAN- enabled devices have a software utility that indicates a user’s
proximity to a WLAN access point.
Service providers place an antenna, or access point, at a designated hot spot. The
antenna transmits a wireless signal to the adapter card in a user’s computer or device.
Users connect to the WLAN through a page in their Internet browser.

Coverage extends over a 50 to 150 meter radius of the access point. Connection
speeds range from 1.6 Mbps, which is comparable to fixed DSL transmission speed,
to 11 Mbps.
New standards promise to increase speeds to 54 Mbps.

Today’s WLANs run in the unlicensed 2.4 GHz and 5 GHz radio spectrums. The 2.4
GHz frequency is already crowded—it has been allocated for several purposes besides
WLAN service. The 5 GHz spectrum is a much larger bandwidth, providing higher
speeds, greater reliability, and better throughput.

Note that the terminology WLAN and WiFi are used interchangeably through out the
document.


Wi-Fi devices
The cost of Wi-Fi components is dropping rapidly. Wi-Fi radio chips which cost
around $100 in 2000 now cost only $15, and fierce competition amongst commodity
radio manufacturers promises to push this price even lower. A future with ubiquitous
Wi-Fi networks in homes, offices and in public spaces will be filled with all kinds of
Wi-Fi enabled devices:

Laptops – According to market research firm In-Stat, 5.7% of all notebooks were
shipped with built-in Wi-Fi radios in 2002, and this share will rapidly grow to 35% in
2003, and to 90% by 2005. This coming only a few years after Wi-Fi became a


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                    5


widely-adopted standard, whereas it took at least ten years for modems and wired
ethernet ports to appear as standard equipment on laptops.


PDAs -- HP and Toshiba have already introduced PocketPC devices with
Wi-Fi built in, and many more Wi-Fi-embedded PDA devices are coming.


Cell phones -- Imagine a cell phone with a low cost Wi-Fi radio that
could opportunistically connect to Wi-Fi hot spots, taking traffic off of
overloaded (and expensive) cellular networks, and sucking in broadband
content like streaming video. A more power-efficient Wi-Fi radio is
necessary for cell phones with small batteries.


Automobiles -- New cars are already packed with data-hungry devices that could
make use of Wi-Fi. Soon you will pull into any service station (in the coming years,
they will all be hot spots) and top up on your data along with your gas. Download
MP3’s, update your navigation system with the latest traffic data, download the day’s
Wall Street Journal audio edition to listen to on the way to work. When you pull
into your garage, your car will “dock” with your home Wi-Fi network. It could also
upload data about itself to your dealer or your insurance company.


Gameboys -- Gaming devices will connect to private and public Wi-Fi
networks and become a platform for multi-player games. Again, a low-
cost add-on to existing products.


Consumer electronics devices -- Once super-cheap low-power Wi-Fi chips are
available, it isn’t a stretch to see them added to all manner of consumer electronics
devices. Anything that could benefit from the ability to send and receive information,
such as MP3 players (download music in any hot spot) and digital cameras (upload
pictures right after you take them wherever you are).




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                    6


1.2. WiFi Network Topology

A basic topology of an 802.11 networks in its simplest form consists of two or more
wireless nodes, or stations (STAs), which have recognized each other and have
established communications.
There are two different cases :

Independent Basic service set(IBSS)…… Within an
IBSS, STAs with each other on a peer-to-peer level. This
type of networks is often formed on a temporary basis,
and is commonly referred to as an ad hoc networks.
Ad hoc networks allow for flexible and cost-effective
arrangements in a variety of work environments,
including hard-to-wire locations and temporary setups
such as group of laptops in a conference room.


The Extended Service Set (ESS) ……consists of a series of BSSs (each containing
an AP) connected together by means of a Distribution System (DS). Although the DS
could be any type of network (including a wireless network), it is almost invariably an
Ethernet LAN. Within an ESS, STAs can roam from one BSS to another and
communicate with any mobile or fixed client in a manner which is completely
transparent in the protocol stack above the MAC sublayer. The ESS enables coverage
to extend well beyond the range of a WLAN radio. By using an ESS, seamless
campus-wide coverage is possible. This service is commonly referred to as
infrastructure mode.




Technology Tracking Dept.                                                     TRA
WiFi Technology                                                         7



Network Components
An 802.11 LAN is based on a cellular architecture where the system is subdivided
into cells, where each cell (called Basic Service Set or BSS) is controlled by a Base
Station (called Access Point or AP).




There are three main links in the WLAN chain that form the basis of the network:

Access Point:
An AP operates within a specific frequency spectrum and uses an 802.11 standard
specified modulation technique. It also informs the wireless clients of its availability
and authenticates and associates wireless clients to the wireless network.
An AP also coordinates the wireless clients' use of wired resources.
The access points generally have two main tasks:
     o They acts as a base station to the users.
     o They acts as a bridge between wireless and wired networks.
It’s a Physical/Data Link Layer device, it supports 1, 2, 5.5, or 11 Mbps connectivity
depending on standard implemented.
The coverage area of AP can be up to 375 ft.(114 m.). The number of users an AP
supports varies but is generally 60-200 users.


A single access point should also be placed as close as possible to the center of
the planned coverage area. If it’s necessary to install the access point in an
obstructed, for security purposes, an optional range extender antenna can
usually be mounte d to extend the range of t he covera ge area.




                                                                            Extender Antenna




Technology Tracking Dept.                                                          TRA
WiFi Technology                                                  8



Network interface card (NIC)/client adapter:
A PC or workstation uses a wireless NIC to connect to the wireless network.
The NIC scans the available frequency spectrum for connectivity and associates it to
an access point or another wireless client.
The NIC is coupled to the PC/workstation operating system using a software driver.
Wireless NICs do same function as standard NICs :
       - change data from parallel to serial.
       - framing & make packets ready for sending.
       - determine the time to send or receive it.
       - transmitting & receiving.



Bridge:
Wireless bridges are used to
connect multiple LANs (both
wired and wireless) at the
Media Access Control (MAC)
layer level.
It’s used in building-to-
building wireless connections,
wireless bridges can cover
longer distances than AP’s
The coverage range can be up
to 25 miles(40 Km).




Technology Tracking Dept.                                                  TRA
WiFi Technology                                                     9


Designing the WLAN Layout:

WLANs can be implemented in a number of ways, depending upon the complexity
desired. Generally, WLANs are thought of in three ways:

1) Peer-To-Peer—A peer-to-peer network is a WLAN in its most basic form. Two
PCs equipped with wireless adapter cards are all that is needed to form a peer-to-peer
network, enabling the PCs to share
resources with one another. While
this type of network requires no
administration or pre-configuration,
it does not allow either PC to access
a     central    server,   inhibiting
client/server computing.
Applications:
– Spontaneous and/or collaborative
work groups
– Small/branch offices sharing
resources
– Remote control of another PC
– Games for two or more players
– Demos

Designing a peer-to-peer network involves three main considerations:
       1. The stations must be arranged so that they are all within the proper
          distance limits.
       2. All stations must send and receive on the same transmission frequency.
          (Most wireless NICs have a factory-set default frequency)
       3. The hidden node problem must be avoided so that each station can
          communicate with all other stations.

2) Client & Access Point—In a Client & Access Point network, users not only
benefit from extended range capabilities, they are also able to benefit from server
resources, as the AP is connected to the wired backbone. The number of users
supported by this type of network varies by technology and by the nature and number
of the transmissions involved. Generally, they can support between 15 and 50 users.




Technology Tracking Dept.                                                     TRA
WiFi Technology                                                    10


3) Multiple Access Points—Although coverage ranges in size from product to
product and by differing environments, WLAN systems are inherently scalable.
As APs have limited range, large facilities such as warehouses and college campuses
often find it necessary to install multiple access points, creating large access zones.
APs, like cell sites in cellular telephony applications, support roaming and AP to AP
handoff. Large facilities requiring multiple access points deploy them in much the
same way as their cellular counterparts, creating overlapping cells for constant
connectivity to the network. As network usage increases, additional APs can be easily
deployed.




Technology Tracking Dept.                                                     TRA
WiFi Technology                                                      11


WLAN Networks Implementation Considerations

When implementing a WLAN solution, customers are confronted with a number of
options and trade-offs that may make one system more suitable than the next. No one
WLAN solution at present can deliver all things to all customers, some, as we have
mentioned, deliver higher speeds, some have better range, etc. The following is a list
of considerations network managers must confront before implementing a wireless
LAN:

Interoperability and Compatibility—The first, and most important job of any
network manager, is to insure that any WLAN products conform to wired
infrastructure interconnection standards. Standards-based interoperability makes the
wireless portion completely transparent to the rest of the network, and is generally
based on Ethernet or Token Ring.
Also, older WLAN systems from different vendors may not always interoperate, even
if they are using the same technology (DSSS or FHSS) and the same frequency band.
A wireless NIC from one vendor may have difficulty connecting to an access point
from another vendor, because vendors may adjust their hardware or software to meet
their own customization requirements and quality standards.
However, the Wireless Ethernet Compatibility Alliance (WECA) now certifies
WLAN vendors whose products are interoperable. The WECA seal (Wi-Fi
Certification) guarantees that WLAN products from different vendors will work
together.

Proprietary versus Standard─ Although WLANs that follow the 802.11 standards
are now widely supported and will likely continue to be so.
However, there are actually a few situations today in which a proprietary WLAN is a
choice. May be to add stations to an existing WLAN, however, replacing a proprietary
WLAN with one that follows the IEEE standard is a more forward-looking choice.
Another reason, to implement an Infrared WLAN. The Infrared WLAN doesn’t
interfere with other communication systems, which makes it the choice to be
deployed near sensitive scientific or medical equipment. Also, because infrared signal
doesn’t penetrate walls, so an infrared WLAN may be suited for a network that
handles a sensitive data, such as in government or military applications.

Peer-to-Peer versus Infrastructure Mode─ The decision regarding whether to
configure the WLAN for peer-to-peer or infrastructure mode should be based upon
the purpose of the network. Peer-to-peer mode should be used when wireless stations
need to communicate only with each other. This mode is good for a temporary
network. Also it’s advisable to connect the peer-to-peer network as a first setup before
installing the infrastructure mode.
For users that need to access the internet or intranet, or for covering a larger area, the
infrastructure made is deployed.

Range And Coverage—Product design and RF and IR propagation determine the
distance over which a signal can transmit information. Objects including walls, metal,
desks, and people can affect how signals propagate, and, therefore, the range a signal
can travel. As we have mentioned before, IR waves cannot travel through opaque
objects and have shorter wavelengths, making them more susceptible to interference,



Technology Tracking Dept.                                                       TRA
WiFi Technology                                                     12


shortening the distance over which they can transmit and receive information. The RF
systems will provide the most range, but sacrifice data rates, while Infrared will
support high data rates with limited range.

Throughput—WLAN throughput rates are a constant source of debate, and
invariably come down to product and setup choices. IR, as we have mentioned,
supports the highest overall data rates, but implementation is difficult. Between the
two RF technologies, it is often quoted that DS systems support a higher data rate than
FH systems on the order of 5:2. While this is true in low usage systems, FH systems
are capable of dividing the allotted spectrum into more channels than DS systems,
and, while supporting slower speeds, can actually support more users and, therefore,
experience fewer bottlenecks.

Interference—WLANs can experience interference from other devices operating on
the same frequencies. The ISM bands, set aside for free usage by most governments,
often have other devices using these same frequencies in close proximity to WLANs.
The 2.4 GHz band, for instance, must compete with microwave ovens for spectrum.
While most WLAN technologies are designed to resist these types of interference, it is
sometimes unavoidable. In addition, FH and DS systems most often cannot be
implemented in the same environment despite the different characteristics of
transmission; networks of the same type, yet different vendors, can often interfere
with one another.

Licensing—The regulators of the countries governs radio transmission, including
those used by WLANs. WLANs are most often operated in the ISM bands we
mentioned previously as they do not require the end user to obtain a license to use the
airwaves. Most countries have declared it is important, when choosing a vendor, to
make sure that they can deliver a product that will conform to the 2.4 GHz portion of
radio spectrum as ISM, but some have not. Products must conform to the spectrum
requirements of the country in which they operate.

Battery Life—Battery life for end-user products varies from vendor to vendor and
technology to technology and can be an extremely important consideration when
designing a wireless network. All vendors typically employ design techniques to
maximize the host computer’s battery life, and some are more successful than others.
Between DS and FH systems, the battery life issue is tilted in favor of FH systems
as they have less bandwidth requirements. Generally, the more bandwidth it takes
to transmit a signal, the greater degree of battery drain.

Safety And Health Concerns—WLAN system output is even less than that of
cellular phones and no illness has ever been attributed to WLANs. Yet, there are
concerns in hospitals when it comes to WLANs as monitoring devices and some
medical devices (heart monitors and pacemakers) operate in the same frequency
range. Hospital network administrators must make sure that any products they
purchase have a sufficient track record of avoiding interference with these types of
devices.




Technology Tracking Dept.                                                     TRA
WiFi Technology                                                   13



Summary
      This section presents the basic topology of WLAN networks. There are two
      main Service Set :
         o Independent Basic Service Set(IBSS) ... ... this represents the Ad hoc
              network with no base station to serve the users.
         o Extended Service Set(ESS) ... ... this represents the infrastructure
              mode where more than a Basic Service Set is deployed, to serve more
              users in a larger area.
      There are three main links in the WLAN chain that form the basis of the network:
         o Access Points … … which acts as the base station to the users, and
              acts as a bridge between the wireless and wired networks.
         o Network Interface Cards … … A PC or workstation uses a wireless
              NIC to connect to the wireless network.
         o Bridge … … Wireless bridges are used to connect multiple LANs.
      WLANs can be implemented in more than one form, depending upon the
      complexity desired:
         o Peer-to-Peer … … which represents the Ad Hoc (or IBSS) networks.
         o Client & Access Point … … where one access point is deployed to
              serve the users in a certain area.(BSS)
         o Multiple Access point … … which represents the infrastructure mode
              (or ESS), where more than one access point is deployed and they are
              connected to the backbone existing network (for example Ethernet or
              Token Ring).
      There are some points must be taken into consideration when designing the
      WLAN network:
         o Interoperability and Compatibility.
         o Proprietary versus Standard.
         o Peer-to-Peer versus Infrastructure Mode.
         o Range and Coverage.
         o Throughput.
         o Interference.
         o Licensing.
         o Battery Life.
         o Safety And Health Concerns.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                    14


1.3. WiFi Radio Topology

The IEEE began to address the need for an interoperability standard among wireless
LANs in 1990. After six drafts, the final proposal was ratified in June of 1997,
specifying WLAN operation in the 2.4 GHz frequency range. The proposal specifies
two layers, the Physical (PHY) and the Media Access Control (MAC).

The physical layer refers to the three technologies supported by the standard,
Frequency Hopping Spread Spectrum (FH), Direct Sequence Spread Spectrum
(DS), and Infrared (IR).
The Media Access Control (MAC) layer is concerned with the rules for accessing the
wireless medium.

1.3.1. IEEE 802.11 PHYSICAL LAYER

The 802.11 PHY layer is divided into two sublayers :
      1. The Physical Medium Dependent (PMD) Sublayer:
                It includes the standards for the characteristics of the wireless
                medium (DSSS, FHSS, or IR).
                It defines the methods for transmitting and receiving data through
                the medium.
      2. The Physical Layer Convergence Procedure (PLCP) sublayer:
                It reformats the data received from the MAC layer into packets
                (Frame) that the PMD sublayer can transmit.
                It listens to the medium to determine when the data can be sent.

Spread Spectrum Technology – Spread spectrum, a digital technology designed to
trade off bandwidth for reliability and security. It comes in two forms, Frequency
Hopping Spread Spectrum (FH), and Direct Sequence (DS). Both forms of Spread

Spectrum consume more bandwidth than a typical narrowband transmission, but
this enables a louder signal, far easier for the receiver to detect than a narrowband
signal. Spread spectrum technologies have security advantages over narrowband
technologies as well.
Although spread spectrum technologies share a common background, there are certain
advantages and disadvantages to the two forms implemented in WLAN applications,
so we offer here a brief comparison.
        Frequency Hopping – Frequency Hopping Spread Spectrum
        (FHSS)combines the bandwidth advantages of a narrowband signal with the
        security and clarity advantages of a wideband signal. FH uses a narrowband
        carrier, as little as one MHz in WLAN applications, that changes frequencies
        at a predetermined rate known to both the transmitter and receiver. This rate
        places the signal on a frequency for a very short period of time, called the
        dwell time, and then directs it to ‘hop’ to the next frequency in the sequence.
        When synchronized in this way, the net effect is to maintain a single logical
        channel. To an unintended receiver, FH appears as impulse noise and is
        ignored. Without the hopping algorithm, FH signals are nearly impossible to
        intercept.



Technology Tracking Dept.                                                     TRA
WiFi Technology                                                  15




             Advantages ─          • Low susceptibility to interference.
                                   • FH systems are also highly scalable as
                                   numerous segments can be placed in the same
                                   area. Each access point creates its own LAN
                                   segment capable of transmitting multiple
                                   transmissions simultaneously. In dense user
                                   environments, many access points can be
                                   connected with overlapping coverage, enabling
                                   load balancing. Load balancing enables the
                                   clients to choose the access point that optimizes
                                   performance. This provides for both a greater
                                   number of users as well as an overall increase in
                                   the system performance.

             Limitations ─      • It doesn’t support more than 2 Mbps.

      Direct Sequence—DS systems spread signals over a wider bandwidth than
      FH systems. For each signal burst sent by a DS system, a redundant ‘chipping
      code’ or chip is generated. Large chips increase the likelihood of recovering
      the original signal as statistical techniques embedded in the receiver can
      recover the original data without the need for retransmission. However, longer
      chipping codes consume more bandwidth than FH transmissions, supporting
      fewer overall channels, and therefore fewer users. Yet, as the signal is spread
      over a larger channel, higher data rates can be supported by DS systems,
      making them ideal for data intensive environments with less overall network
      traffic. DS systems are also extremely secure.



Technology Tracking Dept.                                                   TRA
WiFi Technology                                                     16


       In order to intercept a DS signal, an intruder would have to know the
       frequency range in which the signal was being sent, in addition to the
       algorithm used to ‘decode’ the chipping sequence. As the transmission
       amplitude in DS systems is small, it appears as noise to an unintended
       receiver, making interception extremely difficult.




               Advantages ─       • Secure.
                                  • DS supports higher data rates, 1, 2, 5.5, 11 Mbps.

               Limitations ─      • The spreading of the chipping code is over an 22
                                    MHz channel. Although this lessens the
                                    possibility of interference of the entire signal, it
                                    remains more susceptible to interference than FH
                                    systems, which are spread over an 83 MHz
                                    channel.
                                  • It also limits the number of overlapping cells in a
                                    DS network to three, making continuous coverage
                                    in large facilities more difficult than with FH
                                    systems.

Infrared –Infrared technologies use extremely high frequencies, just below visible
light in the electromagnetic spectrum, and are therefore unable to penetrate solid
objects. Infrared is currently capable of higher data rates than RF, but, due to the
range characteristics, it is not yet cost-effective in WLAN environments.

Infrared requires directed (line of sight) or diffuse (reflective) capabilities for
transmission. Directed WLANs that use line of sight principle, are impractical for
mobile users. Instead they are best designed for a setting where the network devices
are fixed in a stationary position without the possibility of something interfering with
the line of sight.
While diffused WLAN doesn’t require line of sight. Instead it relies on reflected light.
Emitters in a diffused WLAN have a wide-focused beam instead of a narrow beam.
Emitters are usually pointed at the ceiling and use it as the reflection point. When the
emitter transmits an infrared signal, it bounces off the ceiling and fills the room with
the signal. Diffused WLANs covers up to 16 m.



Technology Tracking Dept.                                                     TRA
WiFi Technology                                                     17


Personal area networks and peer-to-peer networks of a few feet in distance are suited
for infrared technology, as is the implementation of fixed sub-network connections
such as LAN bridges. But, as infrared is unable to penetrate opaque objects, we don’t
believe RF technologies are threatened in the near term for enterprise-wide WLAN
solutions.

       Advantages ─       • Infrared light doesn’t interfere with other communication
                          systems as it works in the optical region.
                          •Infrared signal doesn’t penetrate walls, so the signal are
                          kept inside the room. This makes less interference and
                          prevents eavesdropping.

       Limitations ─       • Limited range of coverage (up to 16 m.).
                           • Not applicable for mobile users.
                           • slow data rate (only up to 4 Mbps).

Note: Microwave WLAN technologies are also being used, mainly in WLAN bridge
applications. Data rates and range for microwave products fall between RF and IR
technologies. Microwave has been inhibited thus far by cost and safety issues, as well
as the need for direct line of sight. The FCC has set aside spectrum in the 18.8 to 19.2
GHz bands for use in microwave applications however.
A comparison of the features of light-based infrared, FHSS and DSSS wireless
networks is summarized in the following table.

                               IR                  FHSS                   DSSS
     Causes                    No                   Yes                    Yes
  Interfernce
     Can be                    No                    Yes                   Yes
   interfered
     Power                    Low                Moderate                Moderate
 Consumption
   Coverage                 Limited                Broad                  Broad
  BW (Mbps)                    2                     2                     11


1.3.2. IEEE 802.11 MAC LAYER:

The Medium Access Control (MAC) Layer addresses the following issues:
• Accessing the medium — The 802.11 standard uses an access method known as the
Distributed Coordination Function (DCF). The DCF specifies the use of Carrier
Sense Multiple Access with Collision Avoidance (CSMA/CA) algorithm as the media
access scheme.
• Association—This establishes the wireless links between clients and access points
in the network. Association begins by scanning where the station first scans the air to
know the access points from beacons sent by the access points. Then the association
process begins.
• Reassociation—This is concerned with the handoff of clients as they roam the
network.


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                   18


• Authentication—The 802.11 Standard has two ways of addressing authentication.
By default the standard is an open system, allowing any client with a wireless
connection device to address the network without authentication. The standard does
provide, however, for a more secure network with the Wired Equivalent Privacy
option, by configuring a Shared Key into the AP and its wireless clients. Only those
equipped with the proper key will be allowed to access the AP.
• Power Management—802.11 provides for two separate power modes for the
operation of wireless clients, Active mode and Power Save mode. Active mode is
enabled when a client is transmitting or receiving while Power Save mode is used
when there is no communication to the network. The power management is used to
preserve the power of laptops as they depend mainly on batteries.

1.3.3. IEEE 802.11 Network Layer:

Although IEEE 802.11 specifies the PHY and MAC layer, yet the Network Layer
needs enhancements to allow mobility. This enhancement involves the standard
protocol of sending and receiving data, TCP/IP.

TCP/IP:

Each station on the network is assigned a unique IP address, which consists of 4
bytes. 3 bytes of them represents the IP address of the network, and 1 byte represents
the host IP (or the station IP).
The IP address is unique and fixed to each station, which prevents the mobility and
roaming between networks.

Mobile IP:

Mobile IP provides a mechanism within TCP/IP protocol to support mobility.
In mobile IP, computers are given a home address , which is a static address, on their
home network. The computer also has a home agent, which keeps track of where the
mobile computer is located.
When the mobile computer roams to another network (called a Foreign Network),a
foreign agent provides routing services to the mobile computer and it assigns him a
new, but temporary IP number. So when a data is sent to the mobile computer, to its
home address, the home agent forward it to the foreign agent.
To respond to the original sender, the mobile computer uses traditional IP routing
instead of tunneling back toward its home agent.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                 19



Summary
      This section describes the specification of the PHY and MAC Layer of the
      WLAN networks, besides the enhancements in the network layer.
      The IEEE 802.11 PHY Layer is divided into two sublayers:
           o Physical Medium Dependent (PMD) Sublayer … … which includes
               the standards for the characteristics of the wireless medium (DSSS,
               FHSS, or IR), and defines the methods for transmitting and receiving
               data through the medium.
           o Physical Layer Convergence Procedure (PLCP) sublayer … …
               reformats the data received from the MAC layer into packets (Frame)
               that the PMD sublayer can transmit, and listens to the medium to
               determine when the data can be sent.
      The IEEE 802.11 standard specifies three technologies to be deployed in the
      air interface:
           o Infrared technology.
           o Spread Spectrum technology:
                          • Direct Sequence Spread Spectrum.
                          • Frequency Hopping Spread Spectrum.
      The choice of the required technology depends upon the speed, bandwidth,
      coverage, interference …….. .
        The IEEE 802.11 MAC Layer addresses the following issues:
            o Accessing the medium.
            o Association.
            o Re-association (Roaming).
            o Authentication.
            o Power Management.
        Although IEEE 802.11 specifies the PHY and MAC layer, yet the Network
      Layer needs enhancements to allow mobility, so it introduces the Mobile IP
      protocol as an enhancement to the TCP/IP protocol. In the Mobile IP the user
      is assigned a temporary IP address, if he is roaming outside his home network.




Technology Tracking Dept.                                                  TRA
WiFi Technology                                                        20


1.4. IEEE 802.11 Standards

Today there are a lot of standards used for wireless networking, the attention of this
section is to give a brief overview of the 802.11 standards defined by IEEE, but with
focusing on the most popular standard which is IEEE 802.11b.

The IEEE 802.11 specifications are wireless standards that specify an "over-the-air"
interface between a wireless client and a base station or access point, as well as
among wireless client.

IEEE 802.11 standard primarily addresses two separate layers of the ISO networking
model:

   •   Physical network layer(PHY) - lowest ISO layer that defines the physical
       transmission characteristics of the signal - in this case, radio signal such as the
       frequency, power levels, and type of modulation.
   •   The Media Access Control layer (MAC), is mostly made up of software-
       based protocols that enable devices to talk to each other.


These IEEE 802.11 standards are specifying 9 standards, IEEE 802.11 a-i.

   •   IEEE 802.11a (also called WiFi5):

       It is a Physical Layer (PHY) standard, that works in unlicensed 5-GHz radio
       band using Orthogonal Frequency Division Multiplexing (OFDM).It supports
       data rates from 6 Mbps up to 54 Mbps. It will use the same MAC layer as
       802.11. Products started appearing in 3Q 2001 and 1Q 2002. The 802.11a
       standard includes features like priority for certain types of traffic, also it offers
       much less potential for radio frequency (RF) interference than other PHYs
       (e.g. 802.11b and 802.11g). With high data rates and relatively little
       interference, 802.11a does a great job of supporting multimedia applications
       and densely populated user environments.

   •   IEEE 802.11b (also called WiFi):

       Slightly older standard that supports speeds of 5.5Mbps and 11 Mbps in
       addition to the 1Mbps and 2Mbps data rates. It's deployed in 2.4 GHZ radio
       band. IEEE 802.11b uses CCK(Complementary Code Keying) to provide the
       high data rates.
       IEEE 802.11 finalized this standard (IEEE Std. 802.11b-1999) in late
       1999. Several vendors offer products conforming to this standard.

   •   IEEE 802.11c :

       802.11c provides required information to ensure proper bridge operations.
       This project is completed and product developers utilize this standard when
       developing access points. There is really not much in this standard relevant to
       wireless LAN installers.


Technology Tracking Dept.                                                         TRA
WiFi Technology                                                    21


   •   IEEE 802.11d :

       When 802.11 first became available, only a handful of regulatory domains
       (e.g. U.S., Europe and Japan) had rules in place for the operation of 802.11
       WLANs. In order to support a widespread adoption, the 802.11d task group
       has to define PHY requirements that satisfy global harmonization. This is
       especially important for operation in the 5-GHz bands because the use of these
       frequencies differ widely from one country to another.

   •   IEEE 802.11e:

       This standard works on QoS (quality of service) issue in LANs to optimize the
       transmission of voice and video. There's currently no effective mechanism to
       prioritize traffic within 802.11. As a result the 802.11e task group is refining
       the 802.11MAC to improve QoS for better support of audio and video. The
       802.11e group should finalize the standard by the end of 2002, with products
       probably available by mid-2003.
       Because 802.11e falls within the MAC layer, it will be common to all 802.11
       PHYs and be backward compatible with existing 802.11 WLANs. As a result ,
       the lack of 802.11e being in place today doesn't impact your decision on
       which PHY to use.

       The standard, which is still under development, will use a method called
       Hybrid Coordination Function, or HCF. A final standard is expected in the
       first half of (2003) and will support legacy devices via firmware and device
       driver updates.

   •   IEEE 802.11f:

       Today, a user roaming between access points may lose some packets during
       the handoff between different vendors' devices. The existing 802.11 working
       group purposely didn't define this element in order to provide flexibility in
       working with different distribution systems. The problem, however, is that
       access points from different vendors may not interoperate when supporting
       roaming. 802.11f standard ensures multi-vendor access-point interoperability
       through the Inter-Access Point Protocol, or IAPP. The final standard, expected
       by year's end (may be, more likely in early 2003), will arrive as a flash update
       to legacy access points.
       The inclusion of 802.11f in access point design will eventually open up your
       and add some interoperability assurance when selecting access point vendors.

   •   IEEE 802.11g:

       802.11g is an extension to 802.11b. It will broaden 802.11b's data rates to
       54Mbps within the 2.4 GHz using OFDM(Orthogonal Frequency Division
       Multiplexing)technology. Because of the backward compatibility, an 802.11b
       radio card will interface directly with an 802.11g access point(and vice
       versa)at 11Mbps or lower depending on range.
       A big issue with 802.11g, which also applies to 802.11b, is considerable RF


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                    22


       interference from other 2.4GHz devices, such as the cordless phones. It's
       possible to manage the problem by limiting sources of RF sources of RF
       interference; however, you can't always eliminate the problem. Initial approval
       in August 2002 - Final specification expected during the first half of 2003.

   •   IEEE 802.11h :

       The 802.11a standard faces interference problems in Europe, where it shares
       the 5-GHz frequency band with radar and satellite communications. The
       802.11h provides Dynamic Frequency Selection (DFS)and Transmit Power
       Control(TPC) to deal with this problem, this will make 802.11h the successor
       to 802.11a.

       Dynamic Frequency Selection, or DFS, allows devices to detect such
       transmissions and switch to an alternative channel. The Transmit Power
       Control (TPC) protocol will allow users close to an access point to reduce
       transmission power in order to reduce interference with other users. A final
       standard, expected the end of 2003, will require client device driver and
       access-point firmware updates.

   •   IEEE 802.11i -- Security (Expected to be ratified in September 2003)

       802.11i is actively defining enhancements to the MAC Layer for Enhanced
       Security to counter the issues related to Wired Equivalent Privacy(WEP).The
       existing 802.11 standard specifies the use of relatively weak, static encryption
       keys without any form of key distribution management. This makes it possible
       for hackers to access and decipher WEP-encrypted data on your WLAN.

       Two encryption methods replace the discredited WEP protocol.
       Temporal Key Integrity Protocol (TKIP), is an interim method. It will
       support legacy clients and access points through software updates, but
       cryptographers say TKIP will be broken eventually. The other scheme, based
       on the Advanced Encryption Standard(AES), will offer the best security but
       will likely require new hardware. While the specification won't be final until
       sometime next year, vendors are collaborating to produce an interoperable
       version of TKIP that should be available this year.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                23


Summary
      This section handles the IEEE 802.11 standards and gives a simple
      explanation of the functionality of each of the present nine standards.
      IEEE 802.11a (WiFi 5) … … It is a Physical Layer (PHY) standard, that
      works in unlicensed 5-GHz radio band using Orthogonal Frequency Division
      Multiplexing (OFDM).It supports data rates from 6 Mbps up to 54 Mbps.
      IEEE 802.11b (WiFi) … … Slightly older standard that supports speeds of
      5.5Mbps and 11 Mbps in addition to the 1Mbps and 2Mbps data rates. It's
      deployed in 2.4 GHZ radio band. IEEE 802.11b uses CCK(Complementary
      Code Keying) to provide the high data rates.
      IEEE 802.11c … … provides required information to ensure proper bridge
      operations.
      IEEE 802.11d … … In order to support a widespread adoption, the 802.11d
      task group has to define PHY requirements that satisfy global harmonization.
      IEEE 802.11e … … This standard works on QoS.
      IEEE 802.11f … … ensures multi-vendor access-point interoperability
      through the Inter-Access Point Protocol, or IAPP.
      IEEE 802.11g … … 802.11g is an extension to 802.11b. It will broaden
      802.11b's data rates to 54Mbps within the 2.4 GHz using OFDM(Orthogonal
      Frequency Division Multiplexing)technology.
      IEEE 802.11h … … The 802.11a standard faces interference problems in
      Europe, where it shares the 5-GHz frequency band with radar and satellite
      communications. The 802.11h provides Dynamic Frequency Selection
      (DFS)and Transmit Power Control(TPC) to deal with this problem.
      IEEE 802.11i … … 802.11i is actively defining enhancements to the MAC
      Layer for Enhanced Security.




Technology Tracking Dept.                                                TRA
WiFi Technology                                                    24


1.5. Wi-Fi Security
Special precautions must be taken to maintain security in wireless network. However,
no one approach works for all environments and situations. The optimal solution(s) in
a particular network depends on factors such as the level of security required, size of
the network, whether access is required for remote workers, and so forth.

Securing WLANs is provided through two process: Authentication and Encryption.
Authentication is the means by which one STA is verified to have authorization to
communicate with a second STA. In the infrastructure mode, authentication is
established between an AP and each STA. Authentication is a prerequisite for
association. Association is the establishment of communication services between the
STA and the AP, and mapping the STA to the AP to provide the mobile node with
access to the wired LAN.
Authentication can be either Open System or Shared Key. An Open System, any
requesting STA may be granted authentication. However, success is not guaranteed.
The STA receiving the request may still deny authentication. In Shared Key system,
only stations which possess a secret key can be authenticated. Obviously transmission
of the Shared Key could lead to its interception by unauthorized users. It is therefore
encrypted prior to encryption. Shared Key authentication is available to systems
having the optional encryption capability.

Encryption is intended to provide a level of security comparable to that of a wired
LAN. The encryption algorithm is designated as Wired Equivalent Privacy (WEP).
WEP uses the RC4 PRNG algorithm from RSA Data Security, Inc.
The WEP algorithm was selected to meet the following criteria:
• Reasonably Strong.
• Self-Synchronizing.
• Computationally Efficient.
• Exportable.
• Optional.

Three well-known methods to secure access to an AP are built into 802.11 networks.
These basic methods are widely available and may be sufficient for some
deployments:
• Service set identifier (SSID)
• Media Access Control (MAC) address filtering
• Wired Equivalent Privacy (WEP)

Service set identifier (SSID):
Network access control can be implemented using an SSID associated with an AP or
group of APs. The SSID provides a mechanism to “segment” a wireless network into
multiple networks serviced by one or more APs. Each AP is programmed with an
SSID corresponding to a specific wireless network. To access this network, client
computers must be configured with the correct SSID. A building might be segmented
into multiple networks by floor or department. Typically, a client computer can be
configured with multiple SSIDs for users who require access to the network from a
variety of different locations.
Because a client computer must present the correct SSID to access the AP, the SSID
acts as a simple password and, thus, provides a measure of security. However, this


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                     25


minimal security is compromised if the AP is configured to “broadcast” its SSID.
When this broadcast feature is enabled, any client computer that is not configured
with a specific SSID is allowed to receive the SSID and access the AP. In addition,
because users typically configure their own client systems with the appropriate SSIDs,
they are widely known and easily shared.

Media Access Control (MAC) address filtering:

While an AP or group of APs can be identified by an SSID, a client computer can be
identified by the unique MAC address of its 802.11 network card. To increase the
security of an 802.11 network, each AP can be programmed with a list of MAC
addresses associated with the client computers allowed to access the AP. If a client's
MAC address is not included in this list, the client is not allowed to associate with the
AP.
MAC address filtering (along with SSIDs) provides improved security, but is best
suited to small networks where the MAC address list can be efficiently managed.
Each AP must be manually programmed with a list of MAC addresses, and the list
must be kept up-to-date. In practice, the manageable number of MAC addresses
filtered is likely to be less than 255 clients. In addition, MAC addresses can be
captured and “spoofed” by another client to gain unauthorized access to the network.

Wired Equivalent Privacy (WEP):

Wireless transmissions are easier to intercept than transmissions over wired networks.
The 802.11 standard currently specifies the WEP security protocol to provide
encrypted communication between the client and an AP. WEP employs the symmetric
key encryption algorithm, Ron’s Code 4 Pseudo Random Number Generator (RC4
PRNG).
Under WEP, all clients and APs on a wireless network typically use the same key to
encrypt and decrypt data. The key resides in the client computer and in each AP on
the network. The 802.11 standard does not specify a key-management protocol, so all
WEP keys on a network usually must be managed manually unless they are used in
conjunction with a separate key-management protocol. For example, 802.1X
provides WEP key management. Support for WEP is standard on most current 802.11
cards and APs. WEP specifies the use of a 40-bit encryption key and there are also
implementations of 104-bit keys. The encryption key is concatenated with a 24-bit
“initialization vector” (IV), resulting in a 64- or 128-bit key. This key is input into a
pseudorandom number generator. The resulting sequence is used to encrypt the data
to be transmitted. (WEP keys can be entered in alphanumeric text or hexadecimal
form).
WEP encryption has been shown to be vulnerable to attack. Because of this, static
WEP is only suitable for small, tightly managed networks with low-to-medium
security requirements. In these cases, 128-bit WEP should be implemented in
conjunction with MAC address filtering and SSID (with the broadcast feature
disabled). Customers should change WEP keys on a regular schedule to further
minimize risk.
For networks with high security requirements, the VPN or emerging 802.11i
standards-based solutions are preferable. These solutions are also preferable for large
networks, in which the administrative burden of maintaining MAC addresses on each
AP makes this approach impractical. The point at which the number of wireless client
systems becomes unmanageable varies depending on the organization’s ability to


Technology Tracking Dept.                                                      TRA
WiFi Technology                                                  26


administer the network, the choice of security methods (SSID, WEP, and MAC
address filtering), and its tolerance for risk. If MAC address filtering is used on a
wireless network, the fixed upper limit is established by the maximum number
of MAC addresses that can be programmed into each AP used in an installation. This
upper limit varies, but the practical problem of manually entering and maintaining
valid MAC addresses in every AP on a network limits the use of MAC address
filtering to smaller networks.


Virtual Private Network (VPN), as well as the upcoming IEEE 802.11i standard
addresses weaknesses in 802.11 native security. Both VPN and 802.11i-based security
solutions provide better security and scale well to large networks.
As The IEEE 802.11i standard was explained in the last section, we will discuss now
the VPNs.

VPN:
Virtual Private Network technology (VPN) has been used to secure communications
among remote locations via the Internet since the 1990s. A familiar and already
widely used technology in the enterprise, it can readily be extended to Wi-Fi WLAN
segments on existing wired networks. Although VPNs were originally developed to
provide point-to-point encryption for long Internet connections between remote users
and their corporate networks, they have recently been deployed in conjunction with
Wi-Fi WLANs.
When a WLAN client uses a VPN tunnel, communications data remains encrypted
until it reaches the VPN gateway, which sits behind the wireless AP. Thus, intruders
are effectively blocked from intercepting all network communications. Since the VPN
encrypts the entire link from the PC to the VPN gateway in the heart of the corporate
network, the wireless network segment between the PC and the AP is also encrypted.
This is why VPNs have been recommended to help secure Wi-Fi.




Technology Tracking Dept.                                                   TRA
WiFi Technology                                                27



Summary
      In this section, Securing of WLANs is discussed.
      Securing WLANs is done through two processes; Authentication and
      Encryption.
      Authentication … … is the mean by which one STA is verified to have
      authorization to communicate with a second STA, or with the access point.
      Encryption … … uses certain algorithms to encrypt the data sent between
      stations, so as to prevent intruders from eavesdropping.
      There are three well-known methods to secure access to an AP:
          o Service set identifier(SSID).
          o Media Access Control (MAC) address filtering.
          o Wired Equivalent Privacy (WEP).
      Virtual Private Network (VPN), as well as the upcoming IEEE 802.11i
      standard addresses weaknesses in 802.11 native security.




Technology Tracking Dept.                                                 TRA
WiFi Technology                                                      28


1.6. Wi-Fi Vs Other technologies:
To fairly judge WiFi, we have to compare it with other wireless technologies. So in
this section we will compare it with two important technologies; Bluetooth and 3G.


1.6.1. WiFi and Bluetooth:
Speed: Bluetooth operates at about 720kbps, WiFi at 11Mbps--a big speed difference.
Bluetooth is too slow for video transfers, and probably too slow to move a bunch of
large images off a digital camera. And you wouldn't connect a hard drive to your
computer using Bluetooth.

Applications: Bluetooth is a cable replacement, designed to connect devices point-to-
point. WiFi is designed to hook up an entire network; it can be used to connect one
computer directly to another, but that's not its real purpose. However, there will be
Bluetooth access points to bridge the two networks, but they won't be the best choice
in most applications.

Security: Bluetooth is probably a bit more secure than WiFi. For one thing, Bluetooth
is designed to cover shorter distances than 802.11b; if someone hacks your Bluetooth
network, how much damage can they do? Print to your printer? Also, Bluetooth offers
two levels of (optional) password protection. WiFi has all the security risks associated
with other networks: Once someone has access to one part, he can access the rest.

Ease of use: Bluetooth devices "advertise" their capabilities to others, and a single
device can be connected to up to seven other devices at the same time. This makes it
easy to find and connect to the device you are looking for or to switch between
devices, such as two printers. WiFi is more complex; it requires the same degree of
network management as any comparable wired network.

Power: Bluetooth has a smaller power requirement than WiFi, and devices can be
physically smaller, making it a good choice for consumer electronics devices.

Interference: Bluetooth and WiFi share the same band of frequencies and could,
therefore, interfere with one another. For a variety of technical reasons, Bluetooth is
more likely to interfere with WiFi than vice versa.

Bottom Line: Bluetooth is the choice for connecting single devices when speed isn't a
major issue; it's best suited to low-bandwidth applications such as sharing printers,
syncing PDAs, using a cell phone as a modem, and (eventually) connecting
appliances to one another within a 30- to 60-foot range.

Bluetooth isn't a good replacement for all cables. It's not a great way to connect high-
bandwidth devices, such as external drives or digital video cameras and computers,
Bluetooth is probably not a good choice for downloading stills from your digital
camera to your PC. And WiFi is the best choice for connecting your computers to one
another and to the Internet.




Technology Tracking Dept.                                                       TRA
WiFi Technology                                                     29



1.6.2. WiFi and 3G:
Although the two technologies reflect fundamentally different service, industry, and
architectural design goals, origins, and philosophies, each has recently attracted a lot
of attention as candidates for the dominant platform for providing broadband wireless
access to the Internet. It remains an open question as to the extent to which these two
technologies are in competition or, perhaps, may be complementary.

How are WiFi and 3G alike?

It might appear that 3G and WiFi address completely different user needs in quite
distinct markets that do not overlap. While this was certainly more true about earlier
generations of mobile services when compared with wired LANs or earlier versions of
WLANs, it is increasingly not the case. The end- user does not care what technology
is used to support his service. What matters is that both of these technologies are
providing platforms for wireless access to the Internet and other communication
services.

A. Both are wireless

Both technologies are wireless which:
(1) avoids need to install cable drops to each device when compared to wire line
alternatives; and
(2) facilitates mobility, avoiding the need to install or reconfigure local distribution
cable plant can represent a significant cost savings, whether it is within a building,
home, or in the last mile distribution plant of a wire line service provider.
New base stations are added as more users in the local area join the wireless network
and cells are resized.
This has implications for the magnitude of initial investment required to bring up
WLAN or 3G wireless service and for the network management and operations
support services required to operate the networks. However, it is unclear at this time
which type of network might be lower cost for equivalent scale deployments, either in
terms of upfront capital costs (ignoring spectrum costs for now) or on-going network
management costs.

B. Both are access technologies
Both 3G and WiFi are access or edge-network technologies. This means they offer
alternatives to the last-mile Wireline network. Beyond the last- mile, both rely on
similar network connections and transmission support infrastructure. For 3G, the
wireless.
For WiFi, the wireless link is a few hundred feet from the end-user device to the base
station. The base station is then connected either into the Wireline LAN or enterprise
network infrastructure or to a Wireline access line to a carrier's backbone network and
then eventually to the Internet.

C. Both offer broadband data service
Both 3G and WiFi support broadband data service, although as noted earlier, the
data rate offered by WiFi (11Mbps) is substantially higher than the couple of 100
Kbps


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                   30


expected from 3G services. Although future generations of wireless mobile
technology will support higher speeds, this will also be the case for WLANs, and
neither will be likely to compete with wireline15 speeds (except over quite short
distances).
Both services will also support "always on" connectivity which is another very
important aspect of broadband service. Indeed, some analysts believe this is even
more important than the raw throughput supported.

How different they are?

A. Current business models/deployment are different.

As noted above 3G represents an extension of the mobile service provider model.
This is the technology of choice for upgrading existing mobile telephone services to
expand capacity and add enhanced services.
In contrast, WiFi comes out of the data communications industry (LANs) which is a
by-product of the computer industry. The basic business model is one of equipment
makers who sell boxes to consumers. The services provided by the equipment are free
to the equipment owners.

B. Spectrum policy and management

One of the key distinctions between 3G and WiFi that we have only touched upon
lightly thus far is that 3G and other mobile technologies use licensed spectrum, while
WiFi uses unlicensed shared spectrum. This has important implications for (1) Cost of
service; (2) Quality of Service (QoS) and Congestion Management; and (3) Industry
structure.
Second, while licensed spectrum is expensive, it does have the advantage of
facilitating QoS management. With licensed spectrum, the licensee is protected from
interference from other service providers. This means that the licensee can enforce
centralized allocation of scarce frequencies to adopt the congestion management
strategy that is most appropriate. In contrast, the unlicensed spectrum used by WiFi
imposes strict power limits on users (i.e., responsibility not to interfere with other
users) and forces users to accept interference from others. This makes it easier for a
3G provider to market a service with a predictable level of service and to support
delay-sensitive services such as real-time telephony. In contrast, while a WiFi
network can address the problem of congestion associated with users on the WiFi
network, it cannot control potential interference from other WiFi service providers or
other RF sources that are sharing the unlicensed spectrum (both of which will appear
as elevated background noise). This represents a serious challenge to supporting
delay-sensitive services and to scaling service in the face of increasing competition
from multiple and overlapping multiple service providers.
Third, the different spectrum regimes have direct implications for industry structure.
For example, the FreeNet movement is not easily conceivable in the 3G world of
licensed spectrum. Alternatively, it seems that the current licensing regime favors
incumbency and, because it raises entry barriers, may make wireless- facilities-based
competition less feasible.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                     31


C. Status of technology development is different.

The two technologies differ with respect to their stage of development in a number of
ways. These are discussed in the following subsections.

1. Deployment Status
    While 3G licenses have been awarded in a number of markets at a cost of billions
    of dollars to the licensees, we have seen only limited progress with respect to
    service deployment.

   In contrast, we have a large installed base of WiFi networking equipment that is
   growing rapidly as WiFi vendors have geared up to push wireless home networks
   using the technology. The large installed base of WiFi provides substantial
   learning, scale, and scope economies to both the vendor community and end-
   users.

2. Embedded Support for Services
    Another important difference between 3G and WiFi is their embedded support for
    voice services. 3G was expressly designed as an upgrade technology for wireless
    voice telephony networks, so voice services are an intrinsic part of 3G. In contrast,
    WiFi provides a lower layer data communications service that can be used as the
    substrate on which to layer services such as voice telephony. For example, with IP
    running over WiFi, it is possible to support Voice services would be implemented
    and quality assured over WLAN networks.
    Another potential advantage of 3G over WiFi is that 3G offers better support for
    secure/private communications than does WiFi.

3. Standardization
    It is also possible to compare the two technologies with respect to the extent to
    which they are standardized. Broadly, it appears that the formal standards picture
    for 3G is perhaps more clear than for WLAN. For 3G, there is a relatively small
    family of internationally sanctioned standards, collectively referred to as
    WCDMA. However, there is still uncertainty as to which of these (or even if
    multiple ones) will be selected by service providers. In contrast, WiFi is one of the
    family of continuously evolving 802.11x wireless Ethernet standards, which is
    itself one of many WLAN technologies that are under development.

There are also some form factor issues that may impact the way these services will be
used. Initially, it seems likely that the first 3G end-user devices will be extensions of
the cell phone while the first WiFi end- user devices are PCs. Of course, there are also
3G PC cards to allow the PC to be used as an interface device for PCs, and with the
evolution of Internet appliances (post-PC devices), we should expect to see new types
of devices connecting to both types of networks. However, for mobility, we should
expect to continue to see constraints on size and power requirements that will impose
constraints on the services that are offered.




Technology Tracking Dept.                                                      TRA
WiFi Technology                                                   32



Summary
      In this section, WiFi will criticized through comparing it with other wireless
      technologies, and we took for example; Bluetooth and 3G.
      Bluetooth is used mainly as a cable replacement while WiFi is used mainly
      for connecting stations to each other and to the internet.
      We can’t decide whether 3G and WiFi are in competition or may be
      complementary, as for example the 3G operator may establish WiFi services
      in hotspots as a supplementary service to his customers.
      3G and WiFi are similar in that:        - Both are wireless.
                                              - Both are access technologies.
                                              - Both provide broadband data services.
      3G and WiFi are differ in :             - Current Business model.
                                              - Spectrum policy and management.
                                              - Status of technology development is
                                                different.




Technology Tracking Dept.                                                    TRA
WiFi Technology             33




Technology Tracking Dept.        TRA
WiFi Technology                                                    34


2.1. Roadmap to WiFi

Four key developments have taken place that are contributing to WLAN market
development:
   1. Standards are established. The 802.11 standards have been stable since 1997
   and are widely supported by several manufacturers.
   2. Technology has advanced. Wireless LAN developers have made significant
   strides in addressing issues of security, reliability, speed and distance.
   3. Key vendors have added credibility. With companies like 3Com, Alcatel,
   Breezecom, Cisco, Enterasys, and Wavelink all shipping products, the category is
   far more credible.
   4. Competition has resulted in reduced prices. Wireless LAN access points and
   NICs can be purchased today for $600 and $200 respectively.

On the demand side, four key factors are contributing to growing WLAN opportunity:
   1. Laptop-equipped employees need network access. In fact, the need to support
   laptop-equipped workers is a key driver for WLAN adoption.
   2. PDA-equipped employees increasingly need network access. Increasingly
   widespread use of PDAs is creating a whole new category of WLAN demand.
   3. LAN-related moves/add/changes are costly and disruptive. Much of this
   difficulty relates to the cabling itself. Cabling infrastructure requires ongoing
   expansion and sometimes even replacement.
   4. WLANs are increasingly perceived as a viable substitute to wired LANs.
   Awareness of, and favorability to, the category is rising. In fact, over 40%
   believe their organizations will use WLANs as commonly as they do wired by the
   year 2003.

Wireless Local Area Networks (WLANs) are experiencing significant growth, due to
cost and convenience factors. In many corporate enterprises, WLANs have replaced
or are complementing traditional cabled networks, enabling enterprises to create and
maintain a wireless network throughout their facility — single or multiple buildings
— without the costs and physical limitations experienced with traditional cabling.
WLANs provide unprecedented levels of flexibility for workers, increasing their
productivity by allowing them to roam throughout the corporate facility, easily
collaborating with colleagues, without losing access to network resources.
Demand for roaming access extends outside enterprise boundaries into the public
space. Busy mobile business users want access to their corporate information while on
the road, which has spawned the creation of public wireless access hot spots in a
variety of venues, such as airports and hotels. While public wireless LAN services —
often called Wi-Fi — are still relatively new, user demand for ubiquitous wireless
access is growing rapidly.

As with any new market, the Wi-Fi market offers opportunities to existing — and new
— players. We believe Carriers can capitalize on their existing infrastructure, billing
systems and downstream customer relationships to incorporate this complementary
service offering into their portfolio of services for revenue opportunities, whether
they’re Wireline or Wireless Service Providers.

By 2007, it’s expected that revenue from hot-spot users is projected to equal $3.518
billion and the number of public WLAN hot spots in North America is expected to


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WiFi Technology                                                    35


grow to 38,834, [according to Gartner, Inc.’s “Public Wireless LAN Hot Spots:
Market Trends and Forecasts”report from August 8, 2002].
The public WLAN access market — Wi-Fi — is growing by leaps and bounds and is,
without a doubt, here to stay. Carriers can’t ignore the changing preferences of their
customers, and in fact, should be deliberately looking at the market now in order to
identify their opportunities and position themselves to capture this business.
We believe Carriers have two very attractive opportunities in the Wi-Fi market space:
to offer roaming and hot spot access as part of their overall subscriber service
offering, and to provide managed WLAN services to their enterprise customers.
However, Carriers have their work cut out for them: in the public hot spot market that
means developing hot spot footprints, establishing roaming agreements, and ensuring
that they have the authentication and billing integration to support the business. And
for managed WLAN services, the key challenge will be to create a profitable service
offering that delivers superior customer service. We believe the opportunities are
significant enough to warrant this work, and many Service Providers are ideally
placed to leverage their existing systems, infrastructure and customer relationships to
reap the Wi-Fi rewards.




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WiFi Technology                                                36




2.2. Business Model for WiFi


To establish a good market for WiFi, there must be a well-established Market model
with its players (and the relation between them) are well-defined.
For that we will present in this report two case studies from two different
organizations; one is Boingo which is a wireless ISP launched in 2001,and it was
founded by the chairman of Earthlink(one of the largest ISPs in US).
The second is Bridgewater Systems which offer solutions for subscriber access &
management, provisioning, mediation and network & service management.




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WiFi Technology                                                   37



‘Boingo’ Case Study:

Taking a page from the ISP business


     - In the mid 1990’s, EarthLink created a segmentation map to plot its course in a
       rapidly evolving ISP industry. Unlike all previous attempts to provide
       nationwide ISP service, EarthLink elected not to build its own coast-to-coast
       network. Instead of spending time and money building a big network,
       EarthLink focused on providing great software, support and service to its
       customers, and it left the network build-out to specialist companies who were
       great at that business – and who got economies of scale by also being focused.

     - EarthLink’s segmentation map had three primary industry layers. The physical
       layer companies owned the physical infrastructure, such as phone and cable
       lines. They sold to the next layer up, the network layer companies that built
       and operated Internet backbones with hundreds of points of presence around
       the country. Those companies in turn sold to the brand layer companies on
       the top of the stack who served end users.

Here’s the model showing a sampling of one or two companies at each layer:




     -   Instead of trying to vertically integrate and do it all, the most successful
         industry players focused primarily on one layer of the stack.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                  38



Hot Spot industry segmentation

     - A similar segmentation is taking shape in the Wi-Fi hot spot industry, which
       has four layers:
       o The Venue Layer consists of the companies that own the physical
           locations where hot spots will be deployed.
       o Companies in the hot spot operators Layer contract with venues to
           deploy Wi-Fi gear and operate commercial hot spots.
       o Because of the inherent fragmentation of hot spots, HSOs will partner with
           companies on the Aggregation Layer to provide roaming, software and
           settlement services and drive traffic to their networks.
       o Aggregators in turn enable the Brand Layer companies to offer Wi-Fi
           access to end users.


     - Here is the segmentation map of the hot spot industry with a small sampling of
       companies competing at each layer:




     - As in the ISP space, the most successful companies will focus primarily on
       one industry layer, partner between the layers and compete within their own
       layer.




Technology Tracking Dept.                                                   TRA
WiFi Technology                                                    39


 Venue layer:

      -Venue owners make money in Wi-Fi by either vertically integrating and
       operating their own hot spots, or more commonly by licensing the right to
       deploy hot spots to an HSO.
     - In general, if the HSO pays for 100% of the cost of deploying and managing
       the hot spot infrastructure, they will share very little or none of the revenue
       with the venue owner, at least until the HSO’s costs are recouped. The more of
       the up-front costs paid by the venue owner, the higher their revenue
       participation.
     - Many venue owners are more interested in providing a hot spot as an amenity
       and convenience to their customers than in generating direct revenue.
       Operators of airports, hotels and cafés are quickly realizing that not providing
       a hot spot in their venues will soon mean lost revenues and even lost
       customers.

 Hot spot operators layer:

     - Hotspot Operators (HSOs) are the network provider who deploys and manages
       Wi-Fi networks in public spaces.
     - HSO success is determined by operating the lowest cost networks with the
       highest volume of traffic and revenue. An HSO’s monthly per location costs
       are mostly fixed: depreciation of equipment, hot spot maintenance and back-
       haul costs for a DSL line or T1. Once there’s enough traffic to overcome these
       fixed costs, all additional revenue is pure margin.
     - The network provider may pay the venue a rental fee or revenue split for the
       right to own the network in the venues location. Under other arrangements, a
       network provider acts strictly as an integrator and therefore receives a fixed
       payment for network deployment and management and the venue (such as a
       hotel) receives 100% of the revenue.

Aggregation layer:
     - Aggregators such as Boingo strike wholesale access agreements with HSOs
       and consolidate their hot spots into a single seamless network. They turn
       around and provide a single network to brands, along with software, technical
       support and back-office services.
     - In some cases, brands will have direct relationships with larger HSOs to gain
       access to their hot spots. However, they will still need an aggregator to tie
       those hot spots together into a single network along with thousands of smaller
       HSOs that the brand is unlikely to want to deal with.
     - The brand charges their end user and pays the aggregator fees for network
       aggregation, roaming, settlement, support and software. The aggregator in turn
       settles with each HSO, paying a wholesale connect fee for each of the brand’s
       user connections.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                   40


     - After the industry shakeout, there are likely to be only one or two major
       aggregators. HSOs are unlikely to want to work with more than one
       aggregator, especially if that aggregator already has partnerships with many
       brands representing millions of potential users.




Brands layer:

   - Brands include cellular carriers, ISPs, PC manufacturers and enterprise remote
     access providers seeking to offer a Wi-Fi hot spot service to their customers.
   - An aggregator and roaming are essential to brands, both to provide coverage and
     to drive additional demand to their hot spots.
   - As competition heats up, the most successful players will be the ones most
     focused and who can get economies of scale within a layer. For a company with
     a multi-layer approach, this may mean running each layer as though it were an
     independent entity.
   - For example, several large cellular carriers are now deploying commercial hot
     spots, at the hot spot operators layer, and are launching branded Wi-Fi services,
     at the brands layer. Certainly, they have the capital and expertise to deploy
     networks, and they have relationships with millions of existing customers to
     whom they can promote a Wi-Fi hot spot service.




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                 41



‘Bridgewater Systems’ Case Study:
   - Bridgewater Systems believes the WLAN market will develop through three
     distinct phases over the next two years.




Phase 1: Basic WLAN Access

   •   2002, to mid 2003.
   •   Deployment of basic WLAN service: capitalize on immediate opportunities.
   •   Define pricing structure for WLAN service, understand operational costs, and
       refine business processes

Phase 2: Supplementary Services

   •   Latter half of 2003, basic services should be in place.
   •   Revenue expansion through supplementary services to enhance user
       experience.
   •   Business beginning to grow, margins improving.

Phase 3: Seamless Access, Service & Management

   •   Most of 2004.
   •   Major opportunities in seamless and ubiquitous access.
   •   Solid return on investment - especially for carriers who've invested in
       equipment & infrastructure, and have positioned themselves for success.




Technology Tracking Dept.                                                 TRA
WiFi Technology                                                    42



   - Bridgewater Systems proposed a business model and defined its players as:
           WLAN Hotspot Provider.
           WLAN Service Provider.
           WLAN Clearinghouse.
           Managed WLAN Service Provider.

WLAN Hotspot Provider:

WLAN hotspot providers are deploying hotspots at premium public venues to take
advantage of the increasing subscriber demands for the high-speed access.

Market Model




     - The Hotspot Service Provider does the following:

          •    Set up a network of hotspots for geographical or vertical coverage.
          •    Develop profit-sharing agreements with venue owners.
          •    Exploit existing copper or coax to optimize backhaul costs, or share the
               venue's facilities.
          •    Ensure on capitalizing revenue opportunities from pay-as-you-go
               users, new value-added services.
          •    Invest in remote monitoring & management capabilities to provide
               strong cost savings.


Technology Tracking Dept.                                                     TRA
WiFi Technology                                                 43



Key Revenue Opportunities & Operational Considerations
               Phase 1: Basic WLAN Phase 2: Supplementary Phase 3: Seamless
               Access                 Services            Access, Service &
                                                          Management
Revenue           •   Credit card      •   Usage sensitive           •   Settlement for
                      payment portal       pricing                       service
                  •   Wholesale        •   Tiered service                portability
                      services             offerings                 •   Settlement for
                                       •   Prepaid services              roaming session
                                       •   Pay-per-use                   continuity
                                           access

Services          •   Access           •   Bandwidth and             •   Download user
                  •   Roaming              time limits                   profile to
                                       •   Quality of service            visited hotspot
                                           guarantees                •   Roaming
                                       •   Bandwidth on                  to/from
                                           demand                        3GVoice over
                                       •   Network based                 WLAN
                                           VPN




Technology Tracking Dept.                                                   TRA
WiFi Technology                                                      44


WLAN Service Provider:

WLAN Service Provider offers WLAN access as an add-on service for the existing
subscribers, and to attract new subscribers. It also creates a satisfactory coverage area,
by signing roaming agreements with WLAN hotspot providers and clearinghouses.

Market Model




-WLAN Service Provider can do the following:
     • Creating hot-spot roaming services for their direct subscribers.
     • Creating vertical market offerings to appeal to direct subscribers, such as
         café hot spots, hotel hot spots, and so on.
     • Creating or increasing geographic coverage in strategic markets.
     • Authorizing users based on strong policies, passing these policies in real time
       to the roaming partners in order to establish the subscriber’s service and
       entitlements. (For example, tunnel setup.)
     • Tracking usage to support a variety of billing models, including minutes of
       use, megabytes of data, pay-per-view and so on.
     • Aggregating all usage related to a single Wi-Fi session — including bytes,
       time and chargeable resources —into a single session record, which makes it
       easier for billing systems to translate into a single line item on the user’s bill.
       And eventually, aggregate usage records for a session that roams across a
       variety of access technologies such as 802.11, CDMA plus GPRS services.


Technology Tracking Dept.                                                       TRA
WiFi Technology                                                    45



 -   Like Service Providers, Hot Spot Aggregators connect Wi-Fi users to the
     network, and tend to offer monthly or hourly subscription services direct to
     subscribers. In some cases, these Aggregators will own the hot spots, and in
     others, they will have roaming agreements with hot spot Facility Providers, and
     offer their service either at the wholesale or retail level.
 -   What may differentiate Hot Spot Aggregators is that some of them tend to offer
     their services around a theme or specific vertical market, such as an Aggregator
     that offers hot spot access at hotels, one that offers access at cafés, or one that
     offers services at a variety of airports.

Key Revenue Opportunities & Operational Considerations

               Phase 1: Basic WLAN Phase 2: Supplementary Phase   3:   Seamless
               Access              Services               Access,  Service   &
                                                          Management
Revenue            •   Flat-rate billing      •   Usage sensitive          •   Charging and
                   •   Bundling with              pricing                      settlement for
                       DSL, Dial, 3G          •   Tiered service               service portability
                                                  offerings                •   Charging and
                                              •   Prepaid services             settlement for
                                              •   Pay-per-use access           roaming session
                                              •   Bundling with                continuity
                                                  services

Services           •   Roaming                •   Bandwidth and            •   Download user
                                                  time limits                  profile to visited
                                              •   Quality of service           hotspot
                                                  guarantees               •   Roaming to/from
                                              •   Bandwidth on                 3G
                                                  demand                   •   Voice over WLAN
                                              •   Network based
                                                  VPN




Technology Tracking Dept.                                                      TRA
WiFi Technology                                                46


WLAN Clearinghouse:


A Clearinghouse focuses on brokering relationships - and in particular roaming
agreements - between WLAN hotspot providers and WLAN service providers, it does
the following:

   •   Offer mediation, settlement and reconciliation functions to calculate and
       validate payments between service providers and hotspot providers.
   •   Provide comprehensive reports to these providers .
   •   Broker supplementary service requests.
   •   Provide authentication and mediation for roaming between hotspot networks
       and to/from 3G networks.
   •   The revenue will likely be calculated as a percentage of this revenue flow.

Clearinghouses may also provide settlement and network management services, but
have neither wireless facilities nor subscribers.

Market Model




Technology Tracking Dept.                                                TRA
WiFi Technology                                                   47


Managed WLAN Service Provider:

    - Many enterprises will opt for 802.11 as a managed service, opening up
      opportunities for carriers to act as the managed WLAN service provider.
      Enterprise-wide WLAN deployments can be quite complex. Enterprise IT
      departments may, simply, not have the time or expertise to deal with issues
      such as proper antenna placement, channel selection and security. This creates
      an opportunity for carriers to bundle WLAN managed services with their
      existing connectivity services, particularly since many carriers already have
      customer premises equipment (CPE) in place.

    - As a provider of Managed WLAN Service, his focus is on the enterprise,
      installing and managing WLANs for organizations. As part of his service, he
      manages authentication and access services, allowing enterprise employees to
      reach the enterprise's private network.

    - One can also operate the managed WLAN as a hotspot, allowing visiting
      business partners such as customers or suppliers to reach the Internet or tunnel
      to their home network, through the enterprise WLAN.

Market Model




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                48


Key Revenue Opportunities & Operational Considerations

            Phase 1: Basic Phase                       2: Phase 3: Seamless
            WLAN Access    Supplementary                  Access, Service &
                           Services                       Management
Revenue        •   Flat-rate     •   Usage sensitive       •        Charging      and
                   billing           pricing                        settlement     for
               •   Bundling      •   Pay-per-use                    service
                   with DSL,         access                         portability
                   Dial, 3G      •   Bundling with
                                     services

Services                         •   Quality of service    •        Download user
                                     guarantees                     profile to visited
                                 •   Network based                  hotspot
                                     VPN                   •        Voice over
                                                                    WLAN




Technology Tracking Dept.                                                    TRA
WiFi Technology                                                49



Summary
      In this section, we presented two case studies from two large organizations
      that work in WLAN solutions. The two case studies may be a little similar,
      which indicates that the business model of the WiFi is nearly clear in the
      market.
      In ‘Boingo’ company, they segment the WiFi industry into 4 layers:
          o The Venue Layer consists of the companies that own the physical
              locations where hot spots will be deployed.
          o Companies in the hot spot operators Layer contract with venues to
              deploy Wi-Fi gear and operate commercial hot spots.
          o Because of the inherent fragmentation of hot spots, HSOs will partner
              with companies on the Aggregation Layer to provide roaming,
              software and settlement services and drive traffic to their networks.
          o Aggregators in turn enable the Brand Layer companies to offer Wi-Fi
              access to end users.
      ‘Bridgewater Systems’ proposed a business model and defined its players as:
          o WLAN Hotspot Provider … … WLAN hotspot providers are
              deploying hotspots at premium public venues to take advantage of the
              increasing subscriber demands for the high-speed access
          o WLAN Service Provider … … WLAN Service Provider offers
              WLAN access as an add-on service for the existing subscribers, and to
              attract new subscribers.
          o WLAN Clearinghouse … … A Clearinghouse focuses on brokering
              relationships - and in particular roaming agreements - between WLAN
              hotspot providers and WLAN service providers
          o Managed WLAN Service Provider … … The provider of the
              managed WLAN Service Provider focuses on the enterprise, installing
              and managing WLANs for organizations. As part of his service, he
              manages authentication and access services, allowing enterprise
              employees to reach the enterprise's private network.




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WiFi Technology             50




Technology Tracking Dept.        TRA
WiFi Technology                                                     51



Regulators Trends Regarding WiFi
The spectrum regulatory body of each country restricts signal power levels of various
frequencies to accommodate needs of users and avoid RF interference. Most countries
deem 802.11 WLANs as License free. In order to qualify for license free operation,
the radio devices must limit power levels to relatively low levels.

So it will be demonstrated shortly the status of some regulators.

USA:

   -   In the U.S., the FCC (Federal Communications Commission) defines power
       limitations for wireless LANs in FCC Part 15.247. Manufacturers of 802.11
       products must comply with Part 15 to qualify for selling their products within
       the U.S. Regulatory bodies in other countries have similar rules.
   -   Part 15.247 provides details on limitations of EIRP (equivalent isotropically
       radiated power). EIRP represents the total effective transmit power of the
       radio, including gains that the antenna provides and losses from the antenna
       cable.
   -   Radio NICs in user devices and access points generally have omni-directional
       antennas that propagate RF energy in most directions, which maximizes
       connectivity for mobile applications. When using omni-directional antennas
       having less than 6 dB gain, the FCC rules require EIRP to be 1 watt (1,000
       milliwatts) or less.
   -   The FCC eases EIRP limitations for fixed, point-to-point systems that use
       higher gain directive antennas. If the antenna gain is at least 6 dBi, the FCC
       allows operation up to 4 watts EIRP. This is 1 watt (the earlier limitation) plus
       6 dB of gain.
       For antennas having gain greater than 6 dBi, the FCC requires you to reduce
       the transmitter output power if the transmitter is already at the maximum of 1
       watt. The reduction, however, is only 1 dB for every 3 dB of additional
       antenna gain beyond the 6 dBi mentioned above. This means that as antenna
       gain goes up, you decrease the transmitter power by a smaller amount. As a
       result, the FCC allows EIRP greater than 4 watts for antennas having gains
       higher than 6 dBi.
   -   As it could be see, the deployment of a wireless LAN for typical mobile
       applications using omni-directional antennas is fairly straightforward in terms
       of EIRP limitations. The problems come into play when installing systems to
       connect buildings within a metropolitan area. In this case, attention is paid to
       the FCC rules.
   -   FCC modified Part 15 of its rules to permit new digital transmission
       technologies to operate in the 902-928 MHz (915 MHz), 2400-2483.5 MHz
       (2.4 GHz), and 5725-5850 MHz (5.7 GHz) bands under the current rules for
       spread spectrum systems. The Commission also provided flexibility in the
       design and operation of frequency hopping spread spectrum (FHSS) systems
       in the 2.4 GHz band and eliminated the processing gain requirement for direct
       sequence spread spectrum (DSSS) systems.
   -   The Part 15 rules permit the operation of DSSS and FHSS systems on a non-
       licensed basis where the power density of the transmission signal is reduced,


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WiFi Technology                                                     52


       which lowers the possibility that the transmitter will cause interference to
       other devices operating in the band.(Annex …1 )

Europe:
All WLAN equipment to be used in the 2.4 GHz band must comply with the
European Commission’s Radio and Telecommunications Terminal Equipment
Directive,1999/5/EC (R&TTE) governing radio equipment self-certification and
conformity in accordance with the applicable standards (ETS 300 – 328 for WLANs).

National regulators are responsible for controlling the use of the 2.4 GHz band in their
respective jurisdictions. As a result, regulation varies across different European
countries, with dramatic results on the development of the WLAN market place.
The most advanced markets are in the Nordic region.

       Finland, Norway and Sweden:

       Public access WLANs have moved beyond the pilot phase and are being
       deployed on a commercial basis, where the services are 50% cheaper than
       ADSL.
       Now in Norway, they are launching a hybrid WLAN/GPRS service to offer
       roaming between WLANs and more extended GPRS networks.

       France:

       The major impediment to the growth of the WLAN market in France is the
       limited amount of frequency available and the associated potential problems of
       frequency saturation, interference and service degradation. That is because the
       concerned frequency bands are managed jointly by the Authority and the
       Ministry of Defence.

       When the 2.4 GHz band is released, it shall be possible to use an Effective
       Isotropic Radiated Power (EIRP, thereby including the antenna gain) of 100
       mW on the entire band. From 2004, on the entire territory and on the entire
       band, the effective isotropic radiated power (EIRP) authorised shall be 100
       mW inside the buildings and 10 mW outside the buildings. On this date, for
       frequencies comprised between 2400 to 2454 MHz, the effective isotropic
       radiated power authorised shall be 100 mW inside and outside the buildings.

       The Authority of France has oriented its action in favour of opening the
       WLAN to public according to two priority criteria:

       -   The establishments of networks open to the public as part of local
           development projects:
                  • These networks shall be established experimentally.
                  • These experiments shall allow testing, on a real scale, the
                       performance of this technology in terms of service and usage,
                       as well as the economic models that can be obtained from such
                       projects. In addition, the Authority shall monitor these
                       experiments.
       -   The installation of WLAN access terminals in hotspots:



Technology Tracking Dept.                                                     TRA
WiFi Technology                                                    53


                  •   The installation of WLAN in public places consists in
                      connecting the external terminals to the network open to the
                      public. These terminals are located beyond the termination
                      point of the network.

                  •   As soon as the decision relaxing the use of frequency bands is
                      taken by the Authority and approved by the Ministry in charge
                      of telecommunications, such installations shall not require an
                      individual authorisation in the following two cases:
                      -The terminal is connected directly to an existing network open
                      to the public.
                      -The terminal is connected to the network open to the public by
                      an operator already authorised.

                  •   In a certain number of cases, the installation of WLAN access
                      terminals may require the establishment of a new network or
                      the use of an existing private network by a player not having
                      the operator authorisations.

                  •   The Authority desires to find a satisfactory regulating solution
                      that is sufficiently flexible to meet the needs of the market and
                      to allow the experiments to start rapidly. These networks can be
                      granted an experimental authorisation for networks open to the
                      public. It is proposed to implement a simplified procedure for
                      processing applications for experimental licenses following the
                      spirit of a future general authorisation system.

- Results of Experiments must include:


     -   A technical evaluation, presenting the number of users of the services, peak
         and average output observed per user, the traffic graphs, the measures taken
         by the applicant to ensure continuity of services network and the security,
         particularly against pirating as well as the confidentiality of
         communications. He shall present the user authentication, metering and
         billing procedures.

     -   An evaluation of usage for studying effective use of the resources as well as
         a satisfaction survey conducted among the customers and other inhabitants
         of the coverage zone. This survey shall evaluate the possible jamming
         caused by the experiment and shall be followed by a monitoring and
         corrective procedure.

     -   An economic review for evaluating the commercial conditions of the offer
         (number of subscribers, cost of services) as well as economic feasibility of
         the project.




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WiFi Technology                                                   54


       England:

       The WLANs market in England is in danger due to the following:
       1- The 2.4 GHz band is inherently ‘polluted’. It is used by applications as
          diverse as microwave ovens, cordless phones and license-exempt WLAN
          equipment.
           In the UK, the band is also used by the Military and for licensed
          applications such as outside broadcasting and electronic newsgathering.
          The proliferation of WLAN services, along with other applications, in this
          band could therefore lead to congestion particularly in some areas, e.g.
          business centers, likely to attract ISPs deploying public access WLAN
          services.
       2- ISPs would not be able to provide guarantees regarding quality of service,
          or protection from interference for their commercial services. From the
          perspective of good frequency management, this is reason enough to not
          allow commercial deployment of public access WLANs.
       3- The issues raised in the UK about the 2.4 GHz band congestion, are also
          directly relevant to the on-going consideration in other European countries,
          so there is a direction to move to the 5 GHz band for next generation
          WLAN applications. to achieve higher performance and more resilience to
          interference. This up-band migration will ease congestion in the 2.4 GHz
          band and free frequency for use by home users and Bluetooth applications.
       4- Another argument against commercial WLAN applications is that
          unlicensed use of the 2.4 GHz band will give ISPs an unfair competitive
          advantage in the provision of wireless data services. Providers of 3G
          networks, as well as fixed wireless access networks, have spent enormous
          sums to secure licenses for their wireless services. In the UK, Kingston
          Communications and Atlantic Telecom have also been awarded licenses to
          provide public telecoms services on a regional basis in the 2.4 GHz band.

Asia:
Information from other administrations in this region is difficult to obtain however
there is some information regarding arrangements in Japan which support or could
support the use of IEEE 802.11 devices.
The Japanese spectrum regulatory arrangements support unlicensed low power
services in the 2.4 GHz band on specific frequencies. They also support unlicensed
low power data transmission systems in the band 2483.5-2500 MHz band. The IEEE
802.11 standard includes channel selection arrangements specifically for operation in
Japan. There appears to be little overlap with current arrangements in Europe or
America. The band appears to have been segregated to differentiate between other
equipment and data specific communications devices, including IEEE 802.11 devices.
In the band 5150-5250 MHz the Japanese have a frequency allocation for unlicensed
low power transmission systems limited to indoor use but no allocation in the band
5250-5350 MHz. The band 5770-5850 MHz has an allocation to the unlicensed low
power service (Dedicated Short Range Communication services). The bands 5150-
5250 MHz and 5770-5850 MHz are used for indigenously developed ultra high speed
WLAN service and a mobile data access service. They could potentially support IEEE
802.11a devices operating with fewer channels than are used in the USA, however,
here is insufficient data available to confirm this arrangement.



Technology Tracking Dept.                                                    TRA
WiFi Technology                                                    55


Summary
This section demonstrates the status of some regulators.
USA:
   - In the U.S., the FCC (Federal Communications Commission) defines power
       limitations for wireless LANs in FCC Part 15.247 which provides details on
       limitations of EIRP.
   - It also specifies the operation of DSSS and FHSS systems on a non-licensed
       basis, and this done by specifying the channel bandwidth, the type of
       hopping(in FHSS) ,…… etc. And this reduces the power density of the
       transmission signal which lowers the possibility that the transmitter will cause
       interference to other devices operating in the band

Europe:
 All WLAN equipment to be used in the 2.4GHz band must comply with the
European Commission’s Radio and Telecommunications Terminal Equipment
Directive,1999/5/EC (R&TTE) governing radio equipment self-certification and
conformity in accordance with the applicable standards (ETS 300 – 328 for WLANs).

         Finland, Norway and Sweden:
            - The most advanced markets are in the Nordic region.
            - Public access WLANs have moved beyond the pilot phase and are
               being deployed on a commercial basis.
            - Now in Norway, they are launching a hybrid WLAN/GPRS service to
               offer roaming between WLANs and more extended GPRS networks.
         France:
            - The major impediment to the growth of the WLAN market in France is
               the limited amount of frequency available because the concerned
               frequency bands are managed jointly by the Authority and the Ministry
               of Defence.
            - The Authority of France has oriented its action in favour of opening
               the WLAN to public according to an important criteria, which is the
               establishments of networks open to the public as part of local
               development projects, which shall be established experimentally, and
               the Authority shall monitor these experiments.
Japan:
            -   They support unlicensed low power data transmission systems in the
                band 2483.5-2500 MHz band.
            -   The IEEE 802.11 standard includes channel selection arrangements
                specifically for operation in Japan. There appears to be little overlap
                with current arrangements in Europe or America.
            -   In the band 5150-5250 MHz the Japanese have a frequency allocation
                for unlicensed low power transmission systems limited to indoor use
                but no allocation in the band 5250-5350 MHz.
            -   The band 5770-5850 MHz has an allocation to the unlicensed low
                power service (Dedicated Short Range Communication services).




Technology Tracking Dept.                                                     TRA
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      Annex 1
                        Part 15.247 of FCC




Technology Tracking Dept.                         TRA
WiFi Technology             57




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Technology Tracking Dept.        TRA

				
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