EDGE Technology Report

7/29/2019 EDGE Technology Report

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EDGE

Introduction

The business of wireless data is expected to grow in the region of 100-

200 per cent per annum and the mobile communications industry agrees

that wireless data services will form the foundation for future business.The enormous success of short messaging in many countries proves that

people accept the benefits of non-voice services.

Wireless Applicat ion Protocol (WAP) as well as the higher transmission

sp ee ds of H ig h S pe ed Circu it Switc he d D ata (H SCS D), an d th e

convenience of "always on-l ine" direct internet connections with General

Packet Radio Service (GPRS) these standards enable greater sophistication

a s e nd -u se r s er vic es mo ve t ow ar ds p er so na l mu lt im ed ia . A n ewt echnol ogy, Enhanced Dat a Rat es f or GSM Evo lu ti on ( EDGE) was

i nt roduced t o boost net work capac it y and dat a r at es o f bot h c ir cu it

switching (HSCSD) and packet switching (GPRS), to meet the demands of

wireless mult imedia applicat ions and mass market deployment. With the

introduction of EDGE in GSM phase 2+, exist ing services such as GPRS

and high-speed circuit switched data (HSCSD) are enhanced by offering a

new physical layer . The services themselves are not modif ied. EDGE is

introduced within exist ing specif icat ions and descript ions rather than by

creating new ones.

Many wireless data applicat ions today can be implemented with 9.6kbit /s

da ta . However, bandwidth-hungry f ixed l ine da ta appl ica tions - web

browsing, access to corporate data bases, and so on - would benefit from

higher transmission speeds when used over the mobile network. HSCSD

wi ll s ignif icant ly improve performance, especial ly for t ime-cri ti cal

app li ca ti ons. GPRS wil l enabl e cos t- ef fect ive w ir el es s acces s t oapplicat ions that rely upon data bursts , adding packet switching to GSM

with a packet -based ai r inter face on top of the current ci rcui t swi tched

mode of operation.

Model Engineering College,Thrikkakara 1


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GPRS wil l provide the connect iv i ty needed in packet- swi tched da ta

networks such as the Internet . General Packet Radio Services (GPRS) is a

packet-based wireless communication service that promises data rates

f rom 56 up to 114 Kbps and cont inuous connect ion to the Internet for

mobile phone and computer users. The higher data rates wil l al low users

to take part in video conferences and interact with mult imedia Web si tes

and s imil ar app li ca ti ons usi ng mobil e handhel d dev ices a s wel l a s

notebook computers. GPRS is based on Global System for Mobile (GSM)

communicat ion and wil l complement exis ting serv ices such c ir cui t-

switched ce llular phone connect ions and the Shor t Message Service

(SMS).

In theory, GPRS packet-based service should cost users less than circuit-switched serv ices s ince communica tion channel s a re be ing used on a

shared-use, as-packets-are-needed basis rather than dedicated only to one

user at a t ime. I t should also be easier to make applicat ions available to

mobile users because the faster data rate means that middleware currently

needed to adapt applicat ions to the slower speed of wireless systems wil l

no longer be needed. As GPRS becomes avai l ab le , mobi le user s of a

vir tual private network (VPN) wil l be able to access the private network

continuously rather than through a dial-up connection.

GPRS wi l l a lso complement Bluetooth, a s tandard for replacing wired

connections between devices with wireless radio connections. In addit ion

to the Internet Protocol (IP), GPRS supports X.25, a packet-based protocol

that i s used mainly in Europe . GPRS i s an evolut ionary s tep toward

Enhanced Data GSM Environment (EDGE).

EDGE, a new radio inter face t echnology wi th enhanced modula tion ,

increases the HSCSD and GPRS data r a t es by up to three fo ld . EDGE

modula tion wil l increase the da ta throughput provided by the packet

switched service even over 400kbit /s per carr ier. Similarly, the data rates



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of ci rcui t swi tched data can be increased, or exis t ing data rates can be

achieved using fewer timeslots, saving capacity. Accordingly, these higher

speed data services are referred to as EGPRS (Enhanced GPRS) and ECSD

(Enhanced Circui t Swi tched Data) . GPRS al lows data rates of 115 kbps

and, theore t i ca l ly , of up to 160 kbps on the phys ica l l ayer . EGPRS i s

capable of of fer ing data rates of 384 kbps and, theoret ical ly, of up to

473.6 kbps. A new modulat ion technique and error- tolerant t ransmission

methods, combined wi th improved l ink adaptat ion mechanisms, make

t hese EGPRS r at es pos si bl e. Thi s i s t he key t o i nc reas ed s pect rum

efficiency and enhanced applicat ions, such as wireless Internet access, e-

mail and file transfers.

As a modificat ion to exist ing GSM networks, EDGE does not require newnetwork elements. EDGE is especial ly at tract ive to GSM 900, GSM 1800

and GSM 1900 operators that do not have a l icence for UMTS, but s t i l l

wish to offer competi t ive personal mult imedia applicat ions ut i l is ing the

exis ting band a lloca t ion . Also, EDGE can co-exis t with UMTS, for

ins tance to provide high-speed services for wide-area coverage while

UMTS is deployed in urban hot spots.



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Technical differences between GPRS and EGPRS

Regarded as a subsystem within the GSM standard, GPRS has introduced

packet-switched data into GSM networks. Many new protocols and newnodes have been introduced to make this possible.

EDGE is a method to increase the data rates on the radio l ink for GSM.

Basical ly, EDGE only int roduces a new modulat ion technique and new

channel coding that can be used to t ransmit both packet -swi tched and

circuit-switched voice and data services. EDGE is therefore an add-on to

GPRS and cannot work a lone . GPRS has a grea ter impact on the GSM

sys tem than EDGE has . By adding the new modula t ion and coding to

GPRS and by making adjus tments to the r adio l ink pro tocol s , EGPRS

offers significantly higher throughput and capacity.

GPRS and EGPRS have different protocols and different behavior on the

base station sys tem side. However, on the core network side, GPRS and

EGPRS share the same packet-handling protocols and, therefore, behave in

the same way. Reuse of the exis t ing GPRS core inf ras t ructure (servingGRPS support node/gateway GPRS support node) emphasizes the fact that

EGPRS is only an add-on to the base s tat ion sys tem and is therefore

much easier to introduce than GPRS.

In addi t ion to enhancing the throughput for each data user , EDGE also

increases capacity. With EDGE, the same t ime s lo t can suppor t more

users . This decreases the number of radio resources required to suppor t

the same traff ic, thus freeing up capacity for more data or voice services.

EDGE makes i t easier for circuit-switched and packet-switched traff ic to

coexist while making more efficient use of the same radio resources. Thus

in t ight ly planned networks wi th l imi ted spect rum, EDGE may also be

seen as a capacity booster for the data traffic.



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EDGE technology

EDGE leverages the knowledge gained through use of the exist ing GPRS

standard to deliver significant technical improvements.

Although GPRS and EDGE share the same symbol rate, the modulat ion bit

rate differs . EDGE can transmit three t imes as many bits as GPRS during

the same period of t ime. This is the main reason for the higher EDGE bit

rates.

The di f ferences between the radio and user data rates are the resul t of

whether or not the packet headers are taken into considerat ion. These

dif ferent ways of calculating throughput of ten cause misunders tanding

within the industry about actual throughput f igures for GPRS and EGPRS.

T he d at a r ate o f 3 84 k bp s i s o ft en u se d i n r el at io n to E DG E. T he

International Telecommunicat ions Union ( ITU) has def ined 384 kbps as

the data rate limit required for a service to fulfill the International Mobile



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EDGE modulation technique

The modulat ion type that is used in GSM is the Gaussian minimum shif t

key ing ( GMSK), whi ch i s a k ind o f phase modul at ion. Thi s can be

visual ized in an I /Q diagram that shows the real ( I ) and imaginary (Q)components of the transmitted signal . Transmitt ing a zero bi t or one bi t is

then represented by changing the phase by increments of + _ p. Every

symbol that i s t ransmit ted represents one bi t ; that i s , each shi f t in the

phase represents one bit.

T o a ch ie ve h ig he r b it r at es p er t im e s lo t t ha n th os e a va ila bl e i n

GSM/GPRS, the modulation method requires change. EDGE is specified to

r euse t he channel s tr uc tu re , channel w id th , channel cod ing and t he

exi st ing mechani sms and f unct iona li ty o f GPRS and HSCSD. The

modulat ion s tandard selected for EDGE, 8-phase shif t keying (8PSK),

fulf i lls al l of those requirements. 8PSK modulat ion has the same quali t ies

in terms of generat ing interference on adjacent channels as GMSK. This

makes i t possible to integrate EDGE channels into an exist ing frequency



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plan and to assign new EDGE channels in the same way as standard GSM

channels.

T he 8 PS K mo du la tio n me th od is a li ne ar me th od in w hi ch th re e

consecutive bits are mapped onto one symbol in the I/Q plane. The symbol

ra te , or the number of symbols sent within a cer ta in period of t ime,

remains the same as for GMSK, but each symbol now represents three bi ts

ins tead of one. The total data rate i s therefore increased by a factor of

three. The distance between the different symbols is shorter using 8PSK

modulation than when using GMSK. Shorter distances increase the risk for

misinterpretation of the symbols because i t is more diff icult for the radio

r ecei ve r t o det ec t whi ch s ymbol i t has r ecei ved. Under good r ad iocondit ions, this does not matter . Under poor radio condit ions, however, i t

does . The ext ra bi t s wi l l be used to add more er rorcorrect ing coding,

and the correct information can be recovered. Only under very poor radio

environments is

GMSK more eff icient . Therefore the EDGE coding schemes are a mixture

of both GMSK and 8PSK.

Coding schemes

For GPRS, four different coding schemes, designated CS1 through CS4,

are defined. Each has different amounts of error-correct ing coding that is

optimized for different radio environments. For EGPRS, nine modulat ion

coding schemes, designated MCS1 through MCS9, are introduced. These

fulf i ll the same task as the GPRS coding schemes. The lower four EGPRS

coding schemes (MSC1 to MSC4) use GMSK, whereas the upper f ive

(MSC5 to MSC9) use 8PSK modulat ion. Figure 4 shows both GPRS and

EGPRS coding schemes, along with their maximum throughputs.



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GPRS user throughput reaches saturat ion at a maximum of 20 kbps with

CS4, whereas the EGPRS bit rate continues to increase as the radio quality

increases , unt i l throughput reaches saturat ion at 59.2 kbps . Both GPRS

CS1 to CS4 and EGPRS MCS1 to MCS4 use GMSK modula t ion wi th

sl ightly different throughput performances. This is due to differences in

the header s ize (and payload s ize) of the EGPRS packets . This makes i t

possible to resegment EGPRS packets. A packet sent with a higher coding

scheme ( less e rror correc tion) tha t i s not properly r ece ived, can be

retransmitted with a lower coding scheme (more error correct ion) if the

new radio environment requires it . This resegmenting (retransmitting with

another coding scheme) requires changes in the payload sizes of the radioblocks, which is why EGPRS and GPRS do not have the same performance

for the GMSK modulated coding schemes. Resegmentat ion is not possible

with GPRS.



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Packet handling

Another improvement that has been made to the EGPRS s tandard i s the

abi li ty to retransmit a packet that has not been decoded properly wi th a

more robust coding scheme. For GPRS, resegmentat ion is not poss ible.Once packets have been sent, they must be retransmitted using the original

coding scheme even i f the r adio envi ronment has changed. Thi s has a

signif icant impact on the throughput, as the algori thm decides the level of

confidence with which the link adaptation (LA) must work.

Below is an example of packet transfer and retransmission for GPRS.

A. The GPRS terminal receives data f rom the network on the downl ink.

Due to a GPRS measurement report that was previously received, the l ink

adaptation algorithm in the base station controller decides to send the next

radio blocks (e.g. , numbers 1 to 4) with CS3. During the transmission of

t he se p ac ka ge s, t he c arr ie r- to -i nt er fe re nc e r at io ( C/I ) d ec re as es

dramatically, changing the radio environment. After the packets have been

transmit ted, the network pol ls for a new measurement repor t , including

the acknowledged/unacknowledged bi tmap that te l l s the network which

radio blocks were received correctly.

B. The GPRS handset replies with a packet downlink

acknowledged/unacknowledged message containing the information about

the link quality and the bitmap. In this scenario, it is assumed that packets

2 and 3 were sent erroneously.

C. Based on the new l ink quali ty information, the GPRS l ink adaptat ionalgor i thm wi l l adapt the coding scheme to the new radio environment

using CS1 for the new packets 5 and 6. However, because GPRS cannot

resegment the old packets , packets 2 and 3 must be ret ransmit ted us ing

CS3, although there is a significant risk that these packets still may not be

decoded correctly. As a resul t, the l ink adaptation for GPRS requires



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careful selection of the coding scheme in order to avoid retransmissions as

much as possible. With EGPRS, resegmentat ion is possible. Packets sent

w ith l it tle e rr or p ro te ct io n c an b e r etr an sm itt ed w it h mo re e rr or

protection, if required by the new radio environment. The rapidly

changing radio environment has a much smaller effect on the problem of

choosing the wrong coding scheme for the next sequence of radio blocks

because resegmentation is possible.

Addressing window

Before a sequence of coded radio l ink control packets or radio blocks can

be transmitted over the Um (radio) interface, the transmitter must address

the packets with an identi fi cat ion number. This information i s then

included in the header of every packet. The packets in GPRS are numbered

f rom 1 to 128. Af ter t r ansmiss ion of a sequence of packet s ( e .g . , 10

packets), the transmitter asks the receiver to verify the correctness of thepackets received in the form of an acknowledged/unacknowledged report.

Thi s r epor t informs the t r ansmi t t e r which packet or packet s were not

success fu lly decoded and mus t be r e tr ansmi t ted . S ince the number of

packets is limited to 128 and the addressing window is 64, the packet



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s en di ng p ro ce ss c an r un o ut o f a dd re ss es a ft er 6 4 p ac ke ts . I f a n

erroneously decoded packet must be retransmitted, i t may have the same

number as a new packet in the queue . I f so , the pro tocol be tween the

terminal and the network stal ls , and al l the packets belonging to the same

low-layer capability frame must be retransmitted.

In EGPRS, the address ing numbers have been increased to 2048 and the

window has been increased to 1024 in order to minimize the r i sk for

s tal l ing. This , in turn, minimizes the r i sk for ret ransmit t ing low-layer

capability frames and prevents decreased throughput.

Interleaving

To increase the per formance of the h igher coding schemes in EGPRS

(MCS7 to MCS9) even at low C/I , the inter leaving procedure has been

changed within the EGPRS standard. When frequency hopping is used, theradio environment is changing on a per-burst level . Because a radio block

is interleaved and transmitted over four bursts for GPRS, each burst may

experience a completely different interference environment. If just one of

the four bursts is not properly received, the entire radio block wil l not be

properly decoded and will have to be retransmitted. In the case of CS4 for



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GPRS, har dl y any e rr or p ro tect ion i s u sed a t a ll . W it h EGPRS, t he

s tandard handles the h igher coding scheme di ff erently than GPRS to

combat this problem. MCS7, MCS8 and MCS9 actually transmit two radio

blocks over the four bursts, and the interleaving occurs over two bursts

i ns te ad o f f ou r. T his r ed uc es t he n umb er o f b ur sts t ha t mu st b e

re tr ansmi tt ed should error s occur. The l ike lihood of r ece iv ing two

consecutive er rorf ree bursts i s higher than receiving four consecutive

errorf ree burs ts . This means that the higher coding schemes for EDGE

have a better robustness with regard to frequency hopping.

EGPRS linkcontrolling function

To achieve the highes t poss ible throughput over the radio l ink, EGPRS

uses a combination of two functionalities:

link adaptation and incremental redundancy.

Compared t o a pur e l ink adapt at ion s ol ut ion, t hi s combi na ti on o f

mechanisms significantly improves performance.



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Link adaptation

Link adaptat ion uses the radio l ink quali ty, measured ei ther by the mobile

stat ion in a downlink transfer or by the base stat ion in an uplink transfer ,

to select the most appropriate modulat ion coding scheme for transmissionof the next sequence of packets. For an uplink packet transfer, the network

informs the mobile station which coding scheme to use for transmission of

the next sequence of packets . The modula tion coding scheme can be

changed f or each r ad io b lock ( four bur st s) , but a change i s u sual ly

in it ia ted by new qual ity es timates . The prac ti ca l adapta tion rate i s

therefore decided by the measurement interval.

There are three f ami l i es : A, B and C. Wi th in each fami ly , there i s a

relat ionship between the payload sizes, which makes resegmentat ion for

retransmissions possible.



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EDGE

Incremental redundancy

Incremental redundancy ini t ial ly uses a coding scheme, such as MCS9,

with very l i t t le error protect ion and without considerat ion for the actual

radio l ink quali ty. When information is received incorrect ly, addit ionalcoding is t ransmit ted and then sof t combined in the receiver wi th the

previously received information. Soft-combining increases the probability

of decoding the informat ion. This procedure wi l l be repeated unt i l the

information is successfully decoded. This means that information about

the radio l ink is not necessary to support incremental redundancy. For the

mobi le s ta tions , incrementa l r edundancy suppor t i s mandatory in the

standard.



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EDGE

EDGE Standardization

Standardiza t ion of the f ir st r e leases of the th irdgenerat ion ce llular

sys tems tha t comply with ITU/IMT- 2000 requirements has now been

f inal ized w it h Eur opean Tel ecommuni ca ti ons S tandar ds I ns ti tu te(ETSI/3GPP) Release 99. Two such major systems are Universal Mobile

Telecommunications System (UMTS) and GSM/EDGE.

Fulfilling the EDGE Standardization

EDGE standardization can be divided in three areas:

standardization of the physical layer changes

(definition of the modulation and coding schemes)

the protocol changes for ECSD and

EGPRS.

EDGE standard and references

The EDGE base stat ion system work i tem provides a platform to employ

n ew mo du la ti on t ec hn iq ue s, w he re as t he E DG E n etw or k s up po rt

s ubsyst em wor k i tem def ines t he net work changes t o f ac il it at e t hephysical layer. According to the work item

descriptions, EDGE will provide two phases:

Phase 1: Single- and mul t i s lot packet -swi tched services and s ingle and

multislot circuitswitched services.

Phase 2: Real-time services employing the new modulation techniques that

are not included in Phase 1.

Phase 1 has been completed with 3GPP Release 99. Phase 2 is ongoing in

the 3GPP s tandardizat ion, and i t s scope has been extended to cover the

al ignment wi th WCDMA and the provis ioning of Internet protocol ( IP)

mul t imedia. This concept , current ly s tandardized in 3GPP, i s known as

GERAN.



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EDGE

Requirements on EDGE

From the beginning, the s tandardizat ion of EDGE was res t r icted to the

physical layer and to the introduction of a new modulation scheme. Since

EDGE was intended as an evolut ion of the exis t ing GSM radio accesstechnology, the requirements were set accordingly:

EDGE- and non-EDGE-capable mobile stations should be able to

share one and the same time slot.

EDGE- and non-EDGE-capable transceivers should be deployable

in the same spectrum.

A partial introduction of EDGE should be possible.

To ease implementat ion of new terminals whi le taking into account the

asymmetrical characterist ic of most services currently available, i t was

also decided that two classes of terminals should be suppor ted by the

EDGE standard:

a terminal that provides 8PSK capability in the downlink only

a terminal that provides 8PSK in the uplink and downlink.

EDGE data applications

With EDGE, GSM goes personal multimedia. EDGE will boost all existing

ci rcui t and packet -swi tched services and enable completely new high-

speed data applications.



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EDGE

Enhanced General Packet Radio Service (EGPRS)

The dominant da ta ne tworking pro tocol , on which mos t da ta ne twork

appl ica tions are running, i s TCP/ IP , the In terne t Pro tocol . All web

app li ca ti ons a re r un on s ome f or m o f TCP/I P, whi ch i s by nat ur e aprotocol family for packet switched networks. This means that (E)GPRS is

an ideal bearer for any packet swi tched appl icat ion such as an Internet

connection. From the end user 's point of view, the (E)GPRS network is an

Internet sub-network that has wireless access. Internet addressing is used

and In terne t serv ices can be accessed . A new number , the IP address

number , i s int roduced wi th the telephone number . From the Internet ' s

point of view, the (E)GPRS network is just one sub-network among many

others. Typical EGPRS applications are:

Online Email

Web

Enhanced short messages

Wireless imaging with instant pictures

Video services

Document and information sharing

Surveillance

Voice over Internet

Broadcasting

Enhanced Circuit Switched Data (ECSD)

Some appl icat ions , such as fax and video, require a t ransparent service(constant bi t rates) , while other applicat ions ( the web, e-mail) can work

well with non-transparent services. Typical ECSD applications are:

E-mail download and upload



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EDGE

Bandwidth-secure mobile high speed LAN access

File transfer

Vertical applicat ions such as batch-type f ield sales information or

document transfer

Re al-time ap plic atio ns d ema nd in g a c onstan t b it ra te an d

transmission delay

Time-critical wireless imaging

Mobile videophony

Video on demand

Live video streaming



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EDGE

Deployment of edge

All next-generation wireless networks have three main components:

The radio infrastructure, which includes the cell sites. The packet core infrastructure, which handles only the packet-data

traffic.

The c ir cui t- switched infrast ruc ture , which inc ludes the mobile

swi tching center s (MSCs) , and handles c i rcuit -switched voice

t ra ff ic . Event ua ll y, a s w ir el es s net works evo lve t o an a ll -I P

archit ec ture, voice wil l a l so be packeti zed and t ravel over the

packet core, and the circuit-switched infrastructure will be phasedout.

All current-generat ion wireless networks, regardless of technology, have

ci rcui t -swi tched inf ras t ructure. The packet core i s deployed when an

operator migrates to GPRS, which is the f irs t s tep toward 3G. Because

EDGE is an upgrade to GPRS, i t leverages the investments in the packet

core and circuit-switched infrastructure by re-using them. The majori ty of

t he changes t o dep loy EDGE a re i n t he r ad io i nf ra st ruct ur e, where

software and hardware are added at each cell site.

This approach to migrat ion benef it s customers because the ir EDGE

devices will work on GPRS networks, ensuring EDGE can use their GPRS

dev ices on an EDGE net work because o f t he f or ward and backwar d

compatibility of the GPRS and EDGE technologies/networks.



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EDGE

How Gsm Deploy edge?

Most GSM operators wi l l deploy GPRS before upgrading to EDGE. The

GPRS upgrade lays the foundat ion for EDGE by adding the packet core

infrastructure, which EDGE re-uses.

I f a GSM radio inf ras t ructure i s less than f ive years old (as most GSM

networks in the Americas are) , i t usually can be upgraded from GPRS to

EDGE with sof tware and channel cards . I f the operator has older GSM

radio infrastructure and chooses to replace i t during the GPRS upgrade,

the EDGE upgrade i s s ti ll s imple and cos t e ffect ive because a ll new

GSM/GPRS radio equipment is already designed to support EDGE.

With EDGE, the circuit-switched infrastructure continues to handle only

voice calls. No changes are necessary.

How does an analog or TDMA operator deploy

EDGE?

Analog and TDMA operators that have chosen the GSM-based migrat ion

path to 3G begin by deployi ng a GSM/GPRS network in parallel with their

exis t ing network. Doing so al lows the operator to cont inue generat ing

revenue from their exist ing customers while s igning up new customers for

GSM/GPRS. Depending on thei r business plan, they could choose to

deploy EDGE at the same t ime as their GSM/GPRS deployment, or they

could deploy GSM/GPRS/EDGE in only some places, such as major cities,

and then add EDGE software to the rest of their GSM/GPRS footprint as

market conditions and business plans dictate.



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EDGE

TDMA opera to rs have t he opt ion o f dep loyi ng a GSM/GPRS/ EDGE

over lay alongside thei r TDMA networks at 850 MHz and/or 1900 MHz.

Analog operator s have the option of deploying a GSM/GPRS/EDGE

overlay alongside their 850 MHz networks. Signals travel farther at lower

frequencies, so an 850 MHz EDGE deployment is part icularly at tract ive

because of the excellent propagation CHARACTERISTICS CELL sites

covering large areas, thus reducing the number of s i tes necessary to cover

a market wi th 3G. This makes EDGE par t icular ly favorable for rural

areas.

One f requent opera tor concern , part icu lar ly for those with networks

al ready at capaci ty, i s whether they have enough spect rum to deploy asecond ne twork , especial ly when addi tional spec trum i s expensive or

unavailable. The solution is f irs t to switch the exist ing network to a more

ef fi ci ent f requency re-use pa tt ern, which f rees up be tween 50-90%

spect rum capaci ty . This addi tional capacity can then be used for the

G SM /G PR S/ ED GE n etw or k. S in ce G SM /G PR S is a ls o mu ch m or e

spectrally efficient, GSM can support at least seven times more voice calls

than analog and near ly twice as many as TDMA in the same amount of

spectrum.

Al though EDGE is a data technology, i t a lso helps boost the number of

voice calls that a network can handle simultaneously by sending data more

efficiently than GPRS. With EDGE transmitt ing more data into the same

amount of bandwidth, the voice-coding or vocoder technology in the GSM

voice network can be upgraded to a version thats expected to boost voice

capacity between 15-20%.



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EDGE

Advantages of Edge

Edges advantages can be divided into two categor ies : user benef i t s and

operator benefits.

The key user benefits include:

Speed: EDGE supports theoret ical peak data rates of 473 kbps and

average rates of 110-130 kbps. The average rates are fast enough to

support a wide range of advanced data services, including streaming

audio and video, fast Internet access and large f i le downloads. For

example, a 100 kb Mul t imedia Messaging Services (MMS) video

clip takes 26.7 seconds to download on GPRS but only 10 seconds

on EDGE .

An "always-on" connection: Like cab le b roadband and DSL,

EDGE provides a constant Internet connection, el iminating the need

t o l og on each t ime t o acces s t he I nt er ne t, and cus tomers can

rece ive "pushed" serv ices , such as s tock a lert s. EDGE a lso l et s

cus tomers maintain a data sess ion whi le answer ing a phone cal l .

This is wholly unique to GSM technologies

Value: EDGE is packet -based, which is a more ef f icient way for

opera tor s to provide serv ices . That savings can be passed on to

cus tomers i n t he f or m o f l ower r at es . Packe t a ls o means t ha t

customers pay only for the data that they send and receive instead

of also paying for the air t ime to set up a connection and wait ing for

a server to respond.

Coverage: EDGE is a relat ively inexpensive, s imple upgrade for operators, so EDGE coverage should quickly expand beyond ci t ies

to suburbs and other areas. EDGE also is compatible with GPRS, so

when customers move out of an area with EDGE coverage, they'll be

automatical ly switched to a GPRS network, which are available in



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EDGE

mor e t han 90 count ri es a s o f Apr il 2005. As a r es ul t, EDGE

customers are always assured of having some level of packet-data

service at home and when traveling. With dozens of major operators

deploying EDGE networks on every major cont inent , EDGE wil l

grow rapidly.

Phone selection: Cus tomers w il l have a var ie ty o f cho ices i n

devices and PC cards f rom leading manufac turer s inc luding LG

Electronics, Motorola, Nokia, NEC America, Samsung, Siemens and

Sony Eri cs son. The dev ices s upport GSM/GPRS and wor k on

multiple spectrum bands, including variations of 850/900/1800/1900

MHz.

The key operator benefits include:

Spectral ly effic ient and f lexible: EDGE le t opera tor s quickly

la un ch 3 G w it hi n th ei r e xi sti ng sp ec tr um . A s a n ar ro wb an d

technology that uses 200 kHz channels , EDGE does not require a

large block of spect rum, therefore i t can be deployed in today's

most widely used bands: 850, 900, 1800 and 1900 MHz. The abil i ty

to deploy EDGE within exist ing spectrum without a new 3G l icense

means that an operator can expedi te the launch of 3G services , in

more markets and at a lower cos t than i f i t were necessary to buy

additional spectrum.

Ease of upgrade: EDGE uses the same TDMA f rame s t ruc ture ,

l og ic channel and 200 kHz car ri er bandwid th a s t oday' s GSM

networks . Therefore, deploying EDGE doesn' t require a major re-

engineering of cell plans. If an operator 's radio infrastructure is lessthan f ive years old - as i s the case for most GSM operators in the

Amer icas - then upgrading to EDGE usually r equires only new

software and channel cards for cel l s i tes . As a result , upgrading al l

of the cel l s i tes in a major ci ty takes only a few weeks , al lowing



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EDGE

operators to launch EDGE services quickly. The relat ively low cost

of the EDGE upgrade a l so means tha t opera tor s can pr i ce the i r

advanced services much more compet i t ively than i f the upgrade

required replacing major elements of the radio infrastructure.

Compatibility: EDGE is compatible with other technologies in the

GSM migrat ion path to 3G, so when cus tomers wi th mul t i -mode

phones and PC card modems move out of EDGE coverage, they' re

automatical ly switched to GPRS or WCDMA networks, depending

the data services that they use. EDGE also re-uses the packet-data

network inf ras t ructure deployed for GPRS, making upgrade cos ts

incremental rather than monumental.

Cost-efficiency: Practical experience shows that the cost to upgrade

t o EDGE f rom GSM/GPRS i s about $1- $2 per POP, g iven t he

upgrade only r equires r el a tive ly s imple sof tware and hardware

modifications.

Volumes: More than 165 operators on every major continent have

announced plans to deploy EDGE. As of May 2005, these operator

commitments represented more than 871 mil l ion customers. In the

Americas alone, 70 operators, representing more than 250 mil l ionpotential captive customers, have publicly committed to EDGE.

Cingu la r W ir el es s was t he f ir st ope ra to r t o l aunch EDGE, i n

Indianapol is on June 30, 2003, and [ then] AT&T Wireless [now

Cingular Wireless] launched EDGE nationwide in November 2003.

Operators in Canada, Mexico, South America, the Caribbean, Asia,

E uro pe , a nd A fr ic a h av e a ls o l au nc he d E DG E a nd o pe ra to r

announcements of EDGE deployments worldwide continue to grow.

This market size translates into high volumes of EDGE

infras t ructure and user devices , and one rule of bus iness i s that

h ig he r v olu me s d riv e d ow n c os ts . E DG E o ff er s a ffo rd ab le

infrastructure for operators, and for the consumers i t offers a wide

range of pr ice points on devices . EDGE also wi l l be STANDARD



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EDGE

FEATURE IN UMTS DEVICES wi thout s igni f icantly increasing

their cost.

More control: EDGE includes sophis ticated quali ty-of-service

(QoS) mechanisms that give operators more control , ensuring that

each appl icat ion or cus tomer gets the r ight amount of bandwidth.

QoS is key for a service that targets enterpr ise cus tomers , and i t

helps retain customers while reducing the need for cut-rate pricing

to attract customers to replace those who have churned.



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EDGE

Future of EDGE

The next evolut ionary s tep for the GSM/EDGE cel lular sys tem includes

enhancements of service provisioning for the packet-switched domain and

increased al ignment wi th the service provis ioning in UMTS (UniversalMobile Telecommunicat ions System) /UTRAN (UMTS terrest r ial radio

access network). These enhancements are currently being specif ied for the

coming releases of the 3GPP standard.

Based on EDGE high-speed t ransmission t echniques combined with

enhancements to the GPRS radio l ink interface , GERAN wil l provide

improved suppor t for a l l qual i ty of serv ice (QoS) c las ses def ined for

UMTS: interact ive, background, s treaming and conversat ional . By doing

so, a new range of applications, including IP multimedia applications, will

be adequately supported. This part of the GSM/EDGE evolution focuses

on support for the conversat ional and streaming service classes, because

adequate support for interact ive and background services already exists .

Addi tionally, mul t imedia appl ica tions wil l be supported by para l le l

simultaneous bearers with DIFFERENT QOS characterist ics towards the

same MS , such as mult iple media streams handled through IMS domain.

A driver for such evolution on the packet-switched side is the paradigm

shift within the telecommunications world from circuit to packet-switched

communications.

Both the core network defined for GPRS and the current GSM/EDGE radio

access network require modifications to support enhanced packet services.

The GPRS/EGPRS networks can quickly and cost effect ively evolve withmarket needs, and align with services provided by WCDMA networks.



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EDGE

Conclusions

EDGE wil l provide the solut ion for operators want ing to of fer personal

mult imedia services early and who need to increase the data capacity inthei r GSM network prior to UMTS deployment. EDGE i s especial ly

valuable for operators that do not deploy UMTS.

EDGE will not replace exist ing investments or services but wil l upgrade

them to a highly competitive level through gradual investment.

EDGE rol lout can sat i s fy increased data demand and produce increased

re ve nu es b y first la un ch in g E DG E serv ic e in u rba n a nd o ffice

environments for business users and then providing wider area coverage as

private usage takes off.



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EDGE

Reference

Nokia White paper

Ericsson White Paper

www.3gamericas.org

Documents

EDGE Technology Report