ARIF KAN.G

CISCO N/W ASSOCIATE

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Broadband Wireless Access Technologies

• Wireless Access Technologies– Fixed Broadband Wireless Access

(LMDS/MMDS)– Wireless Local Area Network (WLAN / WiFi)

(IEEE 802.11)– Wireless Metropolitan Area Network

(WMAN / WiMax) (IEEE 802.16)– Cellular Mobile Telephony (GSM-

GPRS,EDGE / CDMA 2000 1x EVDO,EVDD) (3G-UMTS/WCDMA)

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LOCAL MULTIPOINT DISTRIBUTION SYSTEM

(LMDS)

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LOCAL MULTIPOINT DISTRIBUTION SYSTEM

A new radio based access technology with cellular architecture.

LMDS offers flexible high capacity connections to private users and organizations.

LMDS can replace existing phone line cable and other infrastructure.

LMDS can support services such as voice, data video and internet from different platforms like PSTN and ATM.

LMDS can be deployed for providing leased line connectivity to individuals and corporate houses.

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Local Multipoint Distribution System

Broadband wireless technology operating in the 28-GHz and 31-GHz ranges

Voice, data and video Data rate in the range of 100s of Mbps Available 2001? Line-of-sight technology

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LMDS Network

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LMDS Applications

PSTN

Internet

VideoCentral Office

Backhaul forHotspots

Content & Application Providers

LMDS Cell Site

Data,PSTNVideo Access

Data,PSTNVideo Access

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LMDS Cells

LMDS Cell Site

LMDS systems is composedOf cells.

To CO

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Factors Determining LMDS Cell Size

Line-of-sight—LMDS requires direct line Tall buildings may obstruct line of sightTall buildings may obstruct line of sight Solution is to divide area into smaller cellsSolution is to divide area into smaller cells

Antenna height—placed on taller buildings can serve larger cells without obstructions

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LMDS Signal Obstruction

ShadowZone

No Signal

Tall BuildingObstructs Signal

LMDS Cell Site

To CO

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Divide LMDS Cells into Smaller Cells

LMDS Cell Site

LMDS Cell Site

To CO

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LMDS Antenna Height

To CO

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NETWORK ARCHITECTURE OF LMDS

1. Network Operations Centre (NOC)

2. Fiber based infrastructure

3. Central station

4. Customer Premises Equipment

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Network Operations Centre (NOC)

• Contains NMS

• NMS controls a number of CSs & RSs

• NMS can configure maintain and monitor both CS & RS

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2.Fiber based infrastructure

• Interconnects the network node and the CS

• It consists of STM4/STM1 links

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3. Central station

Sub divided into two units

i)Central Controller Station (CCS)

ii)Central Radio Station (CRS)

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3 i) Central Controller Station (CCS)

Provides the interface to Network node

It can be connected to different networks such as PSTN/ATM/IP

It has interfaces to accommodate STM1/STM4,34Mbps,V5.2, for establishing connections to different networks.

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ii)Central Radio Station (CRS)

Microwave transmission and reception equipments.

The height of the antenna should be such that it can provide LOS for the remote stations of targeted area

It uses sectored antennae for broadcasting towards remote stations with coverage range varying from 3 to 10 km depending up on the frequencies used.

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LMDS Hub and Remote Unit

LMDS Hub Unit LMDS Remote Unit

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REMOTE TERMINAL STATION

CONTAINS

1.Roof Top unit

2.Network Interface Unit

3.Customer Premises Equipment

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Roof Top Unit

It uses a directional antenna to establish a M/W link with the Central station

NIU connects the RTU to CPE.

NIU provides the gateway between RF components and in building appliances

NIUs are available in scalable and non scalable forms depending upon customer requirements.

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Scalable(configurable)NIU

•A scalable NIU is flexible and fully configurable.

•It can support two way digital wireless voice,data and video communication for commercial and business use.

•NIU is configured by the NOC at the CS.

•NIUs of this type allows N/W operators to meet customer’s requirement efficiently.

•Costly and is suitable for higher end users

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Non scalable NIU.

•Not configurable.Provides a fixed combination of interfaces

•Cost effective and suitable for medium sized business and home segments.

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FREQUENCY BANDS

LMDS services are available in 3.5GHz,10.5GHz,26GHz and 28GHz.

Frequency Coverage

3.5GHz (3.4-3.6) 10-15km

10.5 (10.15-10.65) 8-10km

26 (24.5-26.5) 3-5km

28 (27.5-29.5) 3-5km

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•The data rate and coverage depends on frequency used and the Geo climatic factors.

•At frequencies above 10GHz rain attenuation is predominant.

•The higher frequency bands are suitable for high density high bit rate users in small area.

•Low frequency LMDS can cover a large area containing scattered low data users.

•BSNL plans to procure the systems in 10.5GHz and 26 GHz frequency bands on primary basis.

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Capacity

•The bandwidth of the radio channel used will normally be 28MHz.

•The system is normally configured with four sectors in a cell and one carrier per sector.

•The number of sectors can be increased or decreased depending upon the traffic.

•The traffic carrying capacity in Mbps depends on the modulation technique employed in the equipment which is vendor dependent,

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Benefits of LMDS

• lower deployment costs • ease and speed of deployment

– systems can be deployed rapidly with minimal disruption to the community and the environment

• fast realization of revenue• demand-based build out

– services and coverage areas can be easily expanded as customer demand warrants

• cost-effective network maintenance, management, and operating costs

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Disadvantages of LMDS

DisadvantagesDisadvantages Requires line-of-sight between buildings;

LMDS network is limited by surrounding objects

Affected by precipitation; LMDS systems are susceptible to interference from rain and fog

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MULTICHANNEL MUTIPOINT DISTRIBUTION SYSTEM (MMDS)

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Similar to LMDS, MMDS can transmit video, voice, or data signals at 1.5 Mbps downstream and 300 Kbps upstream at distances up to 35 miles

Multichannel Multipoint Distribution System

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MMDS Layout

By using lower frequencies, MMDS signals travel longer distances and provide service to cells that are up to 35 miles acrossPizza box (13 x 13 inch) directional antennas are mounted at receiving location

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MMDS Pizza Box Antenna

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Second Generation MMDSWork is underway for Second Generation Work is underway for Second Generation MMDSMMDS Stronger signal will eliminate line-of-sight Stronger signal will eliminate line-of-sight

requirement, increase coverage in cell, and requirement, increase coverage in cell, and simplify antenna installationsimplify antenna installation

Speeds may reach up to 9 Mbps downstream Speeds may reach up to 9 Mbps downstream and 2.0 Mbps upstreamand 2.0 Mbps upstream

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Advantages of MMDSAdvantagesAdvantages

Signal strength—low frequency MMDS RF signal travels farther and with less interference than high-frequency LMDS RF signals

Cell size—seven times larger than area covered by LMDS transmitters

Cost—MMDS is less expensive than LMDS

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Disadvantages of MMDSDisadvantagesDisadvantages Requires direct line-of-sight—makes installation Requires direct line-of-sight—makes installation

difficult and eliminates locations blocked by difficult and eliminates locations blocked by taller obstructionstaller obstructions

Security—Unencrypted transmissions may be Security—Unencrypted transmissions may be intercepted and readintercepted and read

Limited markets—available in limited areas in Limited markets—available in limited areas in USAUSA

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CABLE TV IS GOING WIRELESS

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MMDS - Introduction

• Broadband wireless technology

• Used for Satellite TV signal transmission– MMDS is also known as Wireless Cable

• the frequency range used is – 2.1 to 2.7 GHz. – In US 2.5 to 2.7 MHz (200MHz Band width)

• Maximum coverage area is about 70 Km• Maximum transmitter power is about 100 watts.

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MMDS - Introduction

• Maximum no of analog video chls that can be transmitted in the Band is 33 analog video channels which were 6 MHz wide.

• But in the same band, about 99 Digital video chls can be transmitted

• The MMDS frequency band has room for several dozen analog or digital video channels, along with narrowband channels that can be used by subscribers to transmit signals to the network. – The narrowband channels were originally intended for use in an

educational setting (so-called wireless classrooms).

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What is Wireless LAN / WiFi

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WiFi is the wireless way to handle networking

It is also known as 802.11 networking and wireless networking.

The big advantage of WiFi is its simplicity.

You can connect computers anywhere in your home or office without the need for wires.

The computers connect to the network using radio signals, and computers can be up to 100 feet or so apart.

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WLAN (WiFi), IEEE 802.11

• Wireless Ethernet standards– IEEE 802.11

• The Initial release of the standard capable of transmissions of 1 to 2 Mbps and operates in 2.4 GHz band .

– IEEE 802.11a• Capable of transmissions upto 54 Mbps and operates in 5 GHz

band .– IEEE 802.11b

• Capable of transmissions of upto 11 Mbps and operates in 2.4 GHz band .

– IEEE 802.11g• Capable of transmissions upto 54 Mbps and operates in 2.4

GHz band

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802.11 range Comparisons

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Wi-Fi in Metro Access

• Wifi was originally designed to replace wired last mile (Indoor Ethernet). However operators are trying to use Wi-Fi in Metro Access environment (Outdoor Ethernet). Although not designed for outdoor use, operators are deploying two different approaches to use Wi-Fi as Broadband Metro Access.– Wi-Fi with directional antenna– Wi-Fi with a mesh-network topology

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Increasing 802.11 Range Using Directional Antennas

Internal AccessPoint with hub

Ethernet

Ethernet

Wi-Fi

Wi-Fi

InternetInternet

Wi-Fi Access PointWith High-Gain antenna

Telco core network

Or private (fiber)

network

Wi-Fi Subscriber StationWith High-Gain Antenna

Proprietary Solutions

Customer Premise(Home, Business or HOTSPOT)

802.11 Last Mile Networks

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•A hotspot is a connection point for a WiFi network.

•It is a small box that is hardwired into the Internet.

•The box contains an 802.11 radio that can simultaneously talk to up to 100 or so 802.11 cards.

•There are many WiFi hotspots now available in public places like restaurants, hotels, libraries and airports.

•You can also create your own hotspot in your home, as we will see in a later section.

HOT SPOT

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Adding WiFi to a Computer •Buy a 802.11a, 802.11b or 802.11g network card.• For a desktop machine, install the card inside the machine, or a small external adapter that connect to the computer with a USB cable.

•For a laptop, a PCMCIA card that is slide into a PCMCIA slot on the laptop. Or buy a small external adapter and plug it into a USB port.

•Install the card •Install the drivers for the card •Find an 802.11 hotspot •Access the hotspot.

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What is WiMax?

• Standards-based wireless technology that provides high throughput broadband connections over long distances.

• WiMAX. WiMAX is short for Worldwide Interoperability for Microwave Access, and it also goes by the IEEE name 802.16.

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WiMax would provide:

The high speed of broadband service

Wireless rather than wired access

Broad coverage like the cell phone network instead of the tiny little hotspots of WiFi

WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go

turning your computer on will automatically connect you to the closest available WiMAX antenna.

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A WiMAX system consists of two parts:

A WiMAX tower, similar in concept to a cell-phone tower

A single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles

(~8,000 square km).

A WiMAX receiver - The receiver and antenna could be a small box or they could be built into a laptop the way WiFi access is today

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WiMAX transmitting tower

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WiMAX actually provide two forms of wireless service :

1.Non-line-of-sight, WiFi sort of service, where a small antenna on your computer connects to the tower. In this mode, WiMAX uses a lower frequency range – 2 GHz to 11 GHz

2. line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. Line-of-sight transmissions use higher frequencies, with ranges reaching a possible 66 GHz.

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IEEE 802.16 Specifications

Range - 30-mile (50-km) radius from base station Speed - 70 megabits per second Line-of-sight not needed between user and base station Frequency bands - 2 to 11 GHz and 10 to 66 GHz

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