10 access technology radio

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1/12/2005 Rural Radio Technologies

Rural Radio Technologies :

(CDMA WLL, GSM, corDECT and WiMAX )

Ashish Tayal

DGM (TX-II)

ALTTC Ghaziabad

ALT CENTRE

ALTTC




1. Challenges of Radio Environment

2. RF Spectrum Scarcity and Cellular Concept

Rural Radio Technologies - An Overview

5. Advantages and Limitations of WLL

3. CDMA WLL : Network Architecture and Concepts.

7. CorDECT Solution

6. GSM Architecture and Applications

8. Emerging Technologies – WiMAX.




RADIO TRANSMISSION PROBLEMS

1. Shadowing




RADIO TRANSMISSION PROBLEMS

2. Fading - Occurs due to multi-path signals.




RF SPECTRUM SCARCITY

1. RF Spectrum is a scarce resource and shared by differenttype of users like Defense, Police, Airport Authority etc.

besides by telecom service providers.

2. In our country WPC (Wireless Planning Co-ordination)under Ministry of Communication does the RF Spectrum

allocation to different users of the spectrum based uponthe radio regulation guidelines of InternationalTelecommunication Union ( ITU).

3. Based on these ITU guidelines and other internationaltreaties national frequency allocation plans are evolvedtaking into account requirements and priorities of differentservices.




RF SPECTRUM PLANNING

1. In our country National Frequency Allocation Plan –2002 ( NFAP-2002) has been evolved in line with ITU

Radio Regulations with a view to catering demand ofspectrum for new emerging technologies.

2. NFAP-2002 is effective in our country from 1st January

2002 and forms a basis of spectrum utilization activities inour country.

3. NFAP-2002 has been made a public document and isavailable on web-site www.dot.gov.in




3. Telecom service is provided in the geographical area

covered by a cell by a unit known as BTS (Base Trans-receiver Station ) located close to the center of the cell.

2. For WLL network the geographical area to be served isdivided in cells.

1. Cellular Concept is used to facilitate frequency reuse asradio spectrum is critical resource.

CELLULAR CONCEPT




A Typical Cell Pattern

CELL PATTERN IN WIRELESS WORKING




CELL PATTERN

• Cells may be of different shapes and sizes. Cell shape andsize depends upon the number of users and topography of thearea.

• Cells are kept smaller in size in dense urban environmentand of relatively larger in size in sparsely populated rural areas.




MOBILE COMMUNICATION

• 1 G -analog (cellular revolution)

- Only for voice services.

WIRELESS GENERATIONS

• 2 G - digital (breaking digital barrier)

- Mainly for voice services.

- Data delivery is possible at slow speed.( 9.6 kbps to 144 kbps )

• 3 G - Voice & data ( breaking data speed barrier)

- Superior quality of voice.- Makes feasible MMS ( Multi Media Messaging ) and

other services requiring higher speed data rates.




2. Needed to provided sufficient coverage in entire city.

1. More cells need to be added to the network to meetincreased capacity requirement as subscriber base is

growing up exponentially.

WHY WE NEED MORE CELLS ?




2. As ground based towers are notfeasible at many locations in city areas,so we have to often go for roof-top

towers on existing structures.

1. More cells mean more BTS’s and thusmore towers to mount antenna.

TOWERS AND ANTENNA FOR WLL

A Typical Roof Top Tower




WHAT IS WILL ?

2. It was earlier an access network that provided Telecomservices to subscribers using radio signals as a substitute for copper

for connection between the subscriber and a telephone

exchange.

1. WLL provides last mile connectivity to the subscribers in form

of wireless .

3. The latest version have now full fledged switching capacityas well to work as independent exchange i.e. , MSC based

WLL systems.

4. Present versions of WLL are capable to offer full mobility asin any mobile system.




TelephoneExchange

Architecture of A Typical Wireline Telecom Network

• Call Processing

(Switching & Charging )

Pillar

Pillar

Pillar

Copper cable

Copper wire

One pair of copper wire is dedicated for each subscriber.




TelephoneExchange

A Typical WLL Network

Pillar

Pillar

Pillar

Radio LinkBTS

BTS Radio LinkBSC

Digital Link

BSC : Base Station Controller

MSC : Mobile Switching Centre

MSC

Digital Link

Radio LinkBTS




2. Nowadays roads are used for carrying almost all civicrequirements like water, sewer, Telephone cable, Electricity

and now even metro rail.

WHY WILL ?

1. Traditionally copper has provided link between telephonesubscriber and local exchange.

3. So it has become increasingly difficult to dig and lay coppercable in congested city areas.

Contd..




WHY WILL ?

7. WLL also makes feasible provisioning of telecom servicesin Technically Non Feasible (TNF ) areas i.e. wherecopper cable pairs are either exhausted or not feasible to

be laid.

6. WLL offers freedom of connectivity to the subscribers asmany of the problems related to copper cable are not present since local loop is wireless.

4. Due to frequent digging operation by various agenciesthere are damages to already laid underground coppercables resulting in disruption of services to subscribers.

5. Even basic service providers have to lay cables repeatedlyfor their expansion needs.




FREQUENCY BANDS ALLOCATION FOR CDMA WLL

SERVICES In Our Country

BTS

U P L I N K

D O W N L

I N K

• CDMA up link 824-844 MHzdown link 869-889 MHz

• LOWER BAND FOR UPLINK - HIGHER TRANSMISSION LOSS AT

HIGHER FREQUENCIES.




NETWORK DIAGRAM OF CDMA / WLL SYSTEM

MSCBSC

( V5.2 OR

R2/NO.7 )

BTS

FAX

FWT

2 MbpsDIGITAL

LINK

..

MS

2 MbpsDIGITAL

LINK2 MbpsDIGITAL

LINK

Telecom

Network

BTS

BSC : Base Station Controller

MSC : Mobile Switching CentreFWT : Fixed Wireless Terminal at subscriber premises.

MS : Mobile Station




ADVANTAGES OF WLL - I

1. FAST DEPLOYMENT .

2. FLEXSIBILITY IN PLANNING ,EXPANSION &

RECONFIGURATION.

3. LESS FAULT PRONE -- NO PHYSICAL MEDIUM

4. HIGHLY SUITABLE FOR DIFFICULT, INACCESSIBLETOPOGRAPHICAL CONDITIONS ( TNF CASES).

5. PROVISION OF NEW DIGITAL DATA SERVICES LIKE MMS (

Multi Media Messaging), Streaming Video etc.

Contd..




LIMITATIONS OF WLL - I

1. AT LEAST FOUR TO SIX HOURS AVAILABILITY OF AC POWER IS

PRIME REQUIREMENT FOR SATISFACTORY WORKING OF FWT AT

CUSTOMER PREMISES WHICH IS CAUSING SLOW DEPLOYMENT IN

RURAL AREAS.

2. AS POWER IS KEY REQUIREMENT, PROPER WORKING OF WLL

DEPENDS ON AVAILABILITY OF A.C. POWER IN RURAL AREAS.

3. PORTABILITY OF WLL HANDSETS / FWT’s IS DIFFICULT BETWEEN

DIFFERENT SERVICE PROVIDERS.

Contd..




WLL - APPLICATIONS

1. RURAL COMMUNICATION

- VILLAGE PANCHAYAT TELEPHONE.

- GRAMIN PCO SCHEME.




• Stickiness : Daily traffic info. pushed duringrush hours via SMS/MMS

• Most people need to know the currenttraffic sitution on their route.

• Very useful to city authorities for TrafficManagement.

This service both collects and distributes traffic information. Traffic informationis very important need for city authorities as well as residents.

This service both collects and distributes traffic information. Traffic informationis very important need for city authorities as well as residents.

APPLICATION OVERVIEWAPPLICATION OVERVIEW

2. Traffic Information

WLL - APPLICATIONS




4. AVAILABILITY OF INTERNET AND OTHER COMPUTERISED NETWORKS INVILLAGES

- VERIFICATION OF LAND RECORDS ETC. EVEN DURING VISIT OF

OFFICERS FROM ADMINISTRATION.

- HELPFUL IN HEALTH CARE AND EDUCATION PROGRAMMES.

- ACCESS TO BUS/RAIL/AIR RESERVATIONS.

- ACEESS TO INSURANCE SERVICES.

WLL - APPLICATIONS



Rural Radio Technologies

GSM Network Architecture

BTS

MSC VLR

HLR

PSTNISDN

DataNetworks

Air interface

OSS

BTS

BTS

MSC VLR

BSCBSC




GSM

Radio Specifications - I

• Frequency Bands -Mobile to Cell (UP-LINK) - 890 to 915 MHz

Cell to Mobile (DOWN -LINK) - 935 to 960 MHz

• Channel Bandwidth - 200 KHz

• Access Method - TDMA/FDMA

• Modulation - GMSK




GSM

Radio Specifications - II

• Number of Channels - 124

• Voice Channel Coding - ( 13 Kbps)RPE-LTP

RPE-LTP - Regular Pulse Excitation Long

Term Prediction

FULL RATE - 13Kb/s ; HALF RATE - 6.5 Kb/s

• Bit Rate - 270.833 Kbps




GSM - MULTIPLE ACCESS

• GSM uses both FDMA & TDMA with FDD.

Freq

Mhz.890.2

1

890.4

2

890.6

3

890.8

4

891.0

5 6

914.8

124

• FDMA Access along Frequency axis

• Each RF carrier 200khz apart

• Total 124 RF Channels available.

One or more carrier assigned to each base station

……...




• Both signal and power carried on 3 Twisted Pairs (TP)

• 4 km on 0.5 mm Twisted Pair

DIU

Power +

Signal

TP

corDECT - CBS Interface




supports upto 12 simultaneous voice calls

small, weatherproof unit remotely powered

from DIU or BSD

two antennas for diversity 3600 coverage using omni-directional

antennas

a sector can be covered with directionalantennas

more than one CBS can be deployed to

serve a single sector or cell

Compact Base Station




Wallset – IP• Standard 2W Analog port

– standard Telephone instrument

– G3 FAX

– Voice Band MODEM at 9600 bps min.(14400 bps typ.), V.90

– 12/16 khz metering pulses

– Line reversal

– DTMF - CLIP• Internet port: Serial or Ethernet

– 35/70 kbps Internet, no MODEM

• Built-in Battery

– talk: 3 hrs, standby: 16 hrs.• direct Solar Panel connectivity

• On air software upgrade

Serial Cable




corDECT - Air Interface

• Interface between CBS and the FWT

• DECT Protocol used

– 1880 – 1900 MHz : 20 MHz band needed for operation

– The DECT frame has 24 time slots

5 ms Tx from 5 ms Tx from

Base Station Wallset

1 2 12 13 23 24

480bits

DECT Frame St ructu re





• Dynamic Channel Selection (DCS)

– Decentralised FWT controlled channel selection

– Select best channel for call setup

– During the call - monitors channel for quality - seamless handover– No Frequency planning





• MC-TDMA/TDD– Multi-carrier Time Division

Multiple Access with

Time Division Duplex

– Channel is specified as Frequency, Time-Slot pair

– 12 simultaneous calls

• Authentication andEncryption supported




ROUTER

TO ISP10/100 BaseT

PSTN

E 1 l i n k s

2

E 1 l i n k s

RASs

Ethernet

Switch

1 0

B a s e T

RADIUS

10 Base T • DIU Separates the Voice andInternet Traffic

• Voice Traffic to PSTN

• Internet Traffic to RAS

corDECT - IP Interface




Emerging Technologies : WiMAX




WWAN<15 km

802.20 (proposed)

IEEE View of Wireless Network Technologies IEEE View of Wireless Network Technologies A “Net-Centric” Industry Perspective

Source: ITU, “Birth of Broadband”, September 2003 and Pyramid Research

MAN<5 km

75 Mbit/s

802.16d/e

WiMAXNew standard forfixed broadbandwireless. Doing forMAN what Wi-Fi didfor LAN.

WLAN<100 m

11-54 Mbit/s

802.11a/b/ g

Wi-Fi ®

Includes 802.11a/b/g.Products must beapproved forinteroperability by the

Wi-Fi Alliance. PAN<10 m

802.15.1 (Bluetooth)*

802.15.3 (UWB) **

802.15.4 (ZigBee)**** Bluetooth: ~1 Mbit/s

** UWB: 100 Mbit/s*** ZigBee: 20-250 kbps




What is ?What is ?• WiMAX or “Worldwide Interoperability for Microwave Access” had

its origins in backhaul connectivity using microwave access such asLMDS/MMDS

• WiMAX has become a “hot topic” in the wireless industry, withvisible and aggressive backing from INTEL, among others

• WiMAX is designed to provide “last-mile” or “backhaul”

connectivity using wireless– “Last-mile” refers to a wireless connection from a major trunk line to a

business or residential user

– Using IEEE 802.16 Broadband Wireless Access (BWA) standard, approved inJanuary 2003, to provide operations in the <11GHz spectrum range

– Within the next two years, IEEE 802.16e based systems claim to offer metro-area portability for Internet access for carriers to consider overlaying it inurban areas

WiMAXWiMAX A h U ifi dA h U ifi d




FixedAccess

Cellular

Small to

Mid size

Business

Residential

SOHO

WiMAX Base Station

(Towers or rooftop antennas)

CPE

WiFi/802.11Hotspot

Mobile Network Backhaul

HotSpotBackhaul

WiMAX WiMAX Approach: Unified Approach: Unified

Broadband Access Broadband AccessPortable

Access




Broadband Target Markets Broadband Target Markets Residential Broadband Access Wireless DSL/Wireless Cable

Consumer telephony

Enterprise Broadband Access T1/E1 Replacement

Business telephony

802.11 Hotspot Backhaul

Mobile Network Backhaul

Portable Broadband Access

WiMAX Roaming (regional)

Private MAN Networks Metro Ethernet

802.16

802.11

802.11

802.11

WiMAX claims to address most of these market segments

C h a l l e n g

i n g

W W

A N

WiMAXWiMAX S t (802 11S t (802 11




GHzGHz11 3322 44

ISM: Industrial, Scientific & Medical Band – Unlicensed bandUNII: Unlicensed National Information Infrastructure band – Unlicensed band

UNII

ISM

55

InternationalLicensed

USLicensed

JapanLicensed

InternationalLicensed ISM

WiMAX WiMAX Spectrum (802.11Spectrum (802.11

& 802.16)& 802.16)

WiMAX is considering both licensed and unlicensed

options




ThanksThanks [email protected]

10 access technology radio

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