gsm advanced v1-0 notes

7/25/2019 GSM Advanced v1-0 Notes

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TNC Ltd / Network Consultants 2005

Network Consultants / TNC Ltd 2005 1

The Cellular Academy

GSM Radio Network Planning and Optimisation

Coverage and Cell Structure Planning

Capacity and Frequency Planning

Network Optimisation

Advanced GSM Network Planning Topics

Ver. 1.0


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Contents

2. Repeaters

IntroductionLink BudgetFeedbackTime Delay

RF over fibre

38. Propagation Model Tuning

MeasurementsFilteringTuning with standard clutterTuning with path clutter

Tuning with clutter height

58. Frequency Hopping

Capacity

ParametersPlanning

74. Health and Environment

Power densitySpecific Absorption RateHealth Issues

Safety Guidelines

91. GPRS / EDGE

Packet conceptsGPRS channelsCore networkPDP context activation

Coding and modulationCoverage and capacity

Repeaters


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Repeaters

IntroductionBi-directional linear amplifier

f

1

2

f

1f

f2

Notes:


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Repeaters

IntroductionFeeder (donor) link via GSM Air Interface

No leased line or microwave link required

Cheaper, Smaller, Faster than BSs

Lower investment and running costs

Easy to install

In many cases no building permits required

Lower power consumption

100 Watts / 220 V (2 chans), 45 Watt / 24 V (1 chan)

Solar powering possible

Fewer handovers, less signalling

Notes:


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Repeaters

IntroductionNo increase in cell capacity

Increase of cell area, same number of TCHs

Decrease in capacity density (TCHs per area)

Increased network planning complexity

Feeder link

Decoupling between BS- and MS-side

Time delay problems

No RX diversity

O&M link has to be accomplished via GSMAir Interface (no Abis)

Notes:


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Repeaters

ApplicationsClosing small coverage gaps

Shadow areas (e.g. caused by buildings, hills)

Small towns in rural areas

Providing in-building coverage

Airports, railway stations, exhibition halls

Tunnels, underground parking etc.

Providing line coverage, area coverage

Roads through sparsely populated areas

Irregular terrain, low traffic

Fast interim solution for planned BTS

Notes:


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Repeaters

ApplicationsClosing small coverage gaps

Coverage

dimensionedfor rural

Some suburbanvillages not covered

Local repeatersclose the gaps

Notes:


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Repeaters

ApplicationsProviding in-building coverage

Coveragedimensionedfor outdoors

Notes:


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Repeaters

ApplicationsProviding line coverage, area coverage

Notes:


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Repeaters

Types of repeaterBand selective / channel selective

905 MHz 915 MHz

40 dBm

0 dBm

Band selective

Channel selective

Notes:


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Repeaters

Types of repeaterBand selective

Easy frequency management: No change required if

Frequencies change at donor-BTS

New frequencies are added to donor-BTS

Additional interference due to amplification ofunwanted frequencies from other BTSs

Output power per channel depends on inputspectrum

Notes:


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Repeaters

Types of repeaterChannel selective

Does not amplify signals from other nearby BSs

Need to be re-tuned with new frequency plans

Constant output per channel

Notes:


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Repeaters

Characteristics

Passband gain Gmax 50 . . 80 dB (in 2dB steps)

Max. transmit power 35 dBm

Group delay < 6 s

Dimensions650 x 600 x 400 mm (band-selective)

450 x 350 x 250 mm (channel-selective)

Notes:


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Repeaters

Link budgets

Feeder link

Point to point style

No shadow fading

Nearly constant multipath

Repeater to Mobile

Conventional link budget

Low repeater antenna

Notes:


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Repeaters

Link budgetsUplink, MS to Repeater (900MHz class 4)

MS EIRP 33 dBm

Body loss -2 dB

Repeater RX Antenna gain 16 dBi

Feeder cable loss -3 dB

Repeater Rx Sensitivity -104 dBm

Max path loss (+fade margin) 148 dB

Notes:


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Repeaters

Link budgetsDownlink, Repeater to MS (900MHz class 4)

Max path loss 148 dB

Body loss -2 dB

Repeater TX Antenna gain 16 dBi

Feeder cable loss -3 dB

MS Rx Sensitivity -102 dBm

Required repeater TX power 35 dB

Notes:


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Repeaters

Link budgetsComplete budget: BS - Repeater - MS

Downlink

level level

EIRP MS 33 dBm 33 EIRP BS 34 dBm 34

Body loss -2 dB 31 Cable loss -3 dB 31

Max M S-side path loss +margi 148 dB -117 BS antenna gain 16 dBi 47

MS-side antenna gain 16 dBi -101 Max Feeder link path loss 107 dB -60

Repeater MS-side Cable loss -3 dB -104 Repeater BS side ant gain 18 dBi -42

(Sensitivity) -104 dBm -104 Repeater BS side cable loss -3 dB -45

Max Repeater gain 80 dB -24 -45

Repeater BS side cable loss -3 dB -27 Max Repeater gain 80 dB 35

Repeater BS side ant gain 18 dBi -9 Repeater MS-side Cable loss -3 dB 32

Max Feeder link path loss 107 dB -116 MS-side antenna gain 16 dBi 48

BS antenna gain 16 dBi -100 Max MS-side path loss +margi 148 dB -100Cable and other losses -4 dB -104 Body loss -2 dB -102

(No diversity gain) (No diversity gain)

BS Rx sensitivity -104 dBm MS Rx Sensitivity -102 dBm

Uplink

Notes:


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Repeaters

DecouplingSeparation between repeater transmit and

receive antennas necessary to avoidoscillation (ringing, feedback)

S ~ Gmax + 15 dB

( Gmax : passband gain)

Separation S

f

f

1

1

Notes:


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Repeaters

DecouplingRequired level difference, P0'-P1', between

amplifier input and output signal ~ 15 dB

1f

1f

1f

Measurement point: repeater input

P

P ' - P '

P

0

1

10 Gmax

S

Notes:


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Repeaters

DecouplingLevel difference

P0' - P1' = S - Gmax + CBS + CMS - GBS-MS - GMS-BS

S : Separation (dB) between MS-side- and BS-side-antenna

Gmax : Repeater passband gain

CBS : Cable loss on BS-side (BS-side antenna)

CMS : Cable loss on MS-side (MS-side antenna)

GBS-MS : BS-side antenna gain in direction of MS-side antenna

GMS-BS

: MS-side antenna gain in direction of BS-side antenna

Notes:


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Repeaters

DecouplingAntenna decoupling A

Def.: Includes cable losses

A = S + CBS + CMS - GBS-MS - GMS-BS

= P0' - P1' + Gmax

= Gmax + 15 dB

Repeater passband gain Gmax = A - 15 dB

Rep.

Measurement procedure

S

A

Notes:


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Repeaters

DecouplingVertical separation SV between 2 antennas

SV = A - CBS - CMS = 89 dB ( Gmax = 80 dB, CBS = CMS = 3 dB)

~ 47 + 40 log d (900 MHz)

Approximation must beverified by measurement!

Assumes near field

d ~ 11 m

d

Notes:


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Repeaters

DecouplingRepeater gain must be reduced if

the achievable antenna decoupling is less than 15dB above the max. repeater gain (e.g. due toconstructional constraints)

>>> Reduced coverage area

the donor signal level is higher than e.g. - 60 dBm(the level required for maximum repeater transmitpower )

>>> Less decoupling required

Notes:


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Repeaters

Time delayDifferential time delay

Direct signal BS to MS, and repeated signal havesimilar levels but different propagation times

GSM equaliser corrects up to 15s

Total time delay

Cascaded repeaters extend propagation time tomore than 63 bit periods

Notes:


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Repeaters

Time delayExcess path delay = (t1+td+tn) - tm

Problem if > 16s

(and similar signal levels)

BTS

MS

Rep.t

tt

1

mn

dt

Notes:


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Repeaters

Time delaySimple case

td 6s

Problem if (t1+td+tn) - (t1-tn) > 16s

i.e. if tn > 5s

MS- repeater distance >1.5km

tmtn

t1

td

t1-tn tn

Notes:


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Repeaters

Time delayIf BS,MS and repeater not all in line

Rep.BTSt

2

1

- tmax d

2

t - t < - t - tn m 1max d

Rep.BTS

- tmax d

2

t

21

t - t < - t - tn m 1max d

t1 > 16 - td t1 < 16 - td

1.5km

1.5km

Notes:


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Repeaters

Time delayCascading repeaters

ttot = t1(1) + t1(2) + t1(3) + ... + t1n + n td + tn

t1(1) t1(2) t1(3) t1(3) t1(n) tn

td td td td td td

Notes:


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Repeaters

Neighbour definitions

Notes:


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Repeaters

Traffic issuesRepeaters do not increase the donor's capacity

Increase of cell area, same number of TCHs

Decrease in capacitydensity (TCHs per area)

A capacity check must be performed for thedonor BTS before considering repeaters

BTS

Rep.

Rep.

Rep.Rep.

Rep.

Notes:


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Repeaters

InterferenceRepeater extends:

Coverage- and interference-range of a BS

Interference between repeater's BS-side and otherBS (bi-directional)

Wanted signal

Interfering signal

f1

f11

f1

BTS

BTS

Rep.


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Repeaters

InterferenceInterference situation without repeaters

W/R=6 (12 cell re-use, omni)

BTS BTS BTS BTS

C/I=24 dB 24 dB

50dBmEIRP

50dBmEIRP

R=2km

-86dBm -86dBm

f1 f1

W=12km


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Repeaters

InterferenceInterference situation with repeaters

W/R=6 (12 cell re-use, omni)

BTS BTS BTS BTS

C/I= 32dB 32 dB

50dBmEIRP

50dBmEIRP

R=2km

-78dBm -78dBm

f1 f1

W=12km

Rep. Rep. Rep. Rep. Rep. Rep.

48dBm 48dBm


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Repeaters

InterferenceInterference situation with repeaters

W/R=4 ( < 7 cell re-use, omni)

BTS BTS BTS BTS

24 dB

50dBmEIRP

50dBmEIRP

R=2km

-78dBm -78dBm

f1 f1

W=8km

Rep. Rep. Rep. Rep. Rep. Rep.

48dBm 48dBm

24 dB


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Repeaters

Improving coverage andcapacityRe-use factor of 9 possible for BCCHs

Double capacity?


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Repeaters

Advanced repeater designAvoid need for decoupling by shifting frequency

F1

F2

F1


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Repeaters

Advanced repeater designKeep repeater output power constant

regardless of input by varying gain

- 47 to- 100dBm

+ 35 dBm


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Contents

2. Repeaters

IntroductionLink BudgetFeedbackTime Delay

RF over fibre


MeasurementsFilteringTuning with standard clutterTuning with path clutter

Tuning with clutter height

58. Frequency Hopping

Capacity

ParametersPlanning

74. Health and Environment

Power densitySpecific Absorption RateHealth Issues

Safety Guidelines

91. GPRS / EDGE

Packet conceptsGPRS channelsCore networkPDP context activation

Coding and modulationCoverage and capacity

Propagation

Model Tuning


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Propagation Model Tuning

MeasurementsDynamic range required:

138 + 21+ 10 dB = 169 dB

Transmitter Power (Signal generator) 20.0 dBmPower Amplifier 14.0 dBCable & connector Loss -3.0 dBTx Antenna Gain 5.0 dBiRx Antenna gain 2.0 dBiRx cable loss -2.0 dBReceiver Threshold -136.0 dBmMeasurement Dynamic Range 172.0 dB


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Measurement averagingMinimum distance for averaging window

Enough to eliminate Rayleigh fading

~ 20 wavelengths (ref: WCY Lee)

Maximum distance for averaging window

do NOT eliminate Lognormal shadow fading

Function of average building width/street width

~ 40 wavelengths (ref: WCY Lee)

~ 10 to 15 metres (ref: common sense)


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Measurement averagingOther relevant data

Site geographical co-ordinates & height a.s.l

Tx antenna type and height a.g.l

Tx EIRP

Sketch of antenna installation

Photograph of installation

Route specific information

local features

obstructions on routes

way points to indicate specific features/events


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Map DatabaseMap resolution/Datum reference

Terrain/Topography

accuracy (sea-on-mountain ? reference features)

Clutter/Morphology

consistency (holes in clutter ?)

accuracy (urban-on-sea ?)

Vector

highways, roads

special features

building outlines (microcell)


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Data ProcessingCheck for consistency

Filter out non-useful data

low signal strength (< 10 dB above Rx sensitivity)

doubtful or abnormal data

data position not coincident with road vectors

separate close to BS (~300m),

and far from BS

farther than noise floor distance(cell and clutter dependent)


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Measurement filtering


60

70

80

90

100

110

120

130

140

150

160

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2Log (Dist,km)

MeasuredPL,

dB

Measurements closeto the noise floor

Measurements below

the antenna beam


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Measurement filteringby path loss


Area ofmeasurement

points

Remove measurementswith Path Loss > X

Remove measurementswith Path Loss < X

Regression slope

True slope


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Measurement filteringby path loss AND distance

Meas PL (dB)

80

90

100

110

120

130

140

150

160

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

Doubtful measurements


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Aim: To find values for AF and L1Ln

A + B log (F) + C log (Hb) + [D + E log(Hb)] log D + Lc

B can be ignored for single frequencymodels

A can be adjusted to zero mean error at theend of the process

Step 1: Find suitable start value for D


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Establishment of slope valueMixing clutter types affects average slope

Lower clutter loss further from the BS makesthe slope shallower

Measured

y=Pathgain

Predicted

K1

x=Log (distance)

0 (d = 1 m) 1 (d = 10 m) 2 (d = 100 m) 3 (d = 1 km) 4 (d = 10 km)

Slope = dy/dx = K2/log10

K2


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Establishment of slope value1. Separate results into different clutter types

2. Filter measurements separately

3. Calculate regression slope for each clutter

4. Calculate weighted average of slopes

Seed value for D


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Iterative tuning of parametersWithout path clutter

Take calculated slope value D

Remaining values to establish: C & E

Only possible with various heights of BS or, case ofother height algorithms, difference in BS-MS height

Calibration of clutter values (Lc) is trivial

D = seedC =13.8

E = -6.55

Calculatevalues

of Lc

Vary E to

minimiseSt. Dev.

To calculate values for L1 to Ln, first set them all to zero. Then run the analysis.

The mean errors for the individual clutter classes give values for L1 to Ln


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Iterative tuning of parametersWithout path clutter

D = seed

C =13.8E = -6.55

Calculatenew values

of Lc

Vary E tominimise

St. Dev.Calculate

new valuesof Lc

Vary C to

minimise

St. Dev.Calculatenew values

of Lc

Vary D tominimiseSt. Dev.

Repeat loop until

standard deviationis minimised


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Path clutterEssential for resolutions of less than 50m

Weighted averageof nearby clutteroffset values

Rx

DclutterTo Tx

[ ]=

=n

i

clutterneff iLfKL0

)(

resolutionprediction

Dn clutter

_=

BS

Open

D. UrbanUrban

Suburban


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Iterative tuning of parametersWith path clutter

Calculation of Lc values is no longer trivial

D = seedC =13.8

E = -6.55

Vary L1 to

minimiseSt Dev

Vary E tominimiseSt. Dev.

Vary C tominimiseSt. Dev.

Vary D tominimise

St. Dev.

Repeat loop untilstandard deviation

is minimised

Vary L2 to

minimiseSt Dev

Vary L3 tominimise

St Dev

Vary Ln tominimise

St Dev


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Iterative tuning of parametersReasonable values for parameters

C: 10 to 25

D: 25 to 50

E: 0 to -12

L (urban): +5 to -10

L (suburban): 0 to -15

L (quasi open): -5 to -25

L (water): -10 to -30

Absolute values for L not so important as relative values


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Effective height algorithmsSlope

( ) slopembeff dkHHH = slopeandslopedefine minmax:


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Effective height algorithmsAverage

[ ]=

=n

i

profileeff ihH0

)(

A: Start Point B: End Point

pixelsize

ddnwhere AB

=


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Effective height algorithmsDifference

Hb

Ho

Heff

Define max and min Heff


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Contents

2. Repeaters

IntroductionLink BudgetFeedback

Time DelayRF over fibre


MeasurementsFilteringTuning with standard clutter

Tuning with path clutterTuning with clutter height

58. Frequency HoppingCapacity

ParametersPlanning

74. Health and EnvironmentPower densitySpecific Absorption RateHealth Issues

Safety Guidelines

91. GPRS / EDGEPacket conceptsGPRS channelsCore network

PDP context activationCoding and modulationCoverage and capacity

Frequency

Hopping


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Frequency hopping

Capacity calculationNumber of frequencies

Number of Frequency-Timeslots

Subtract SDCCH & BCCH Timeslots

Load factor X remaining Frequency-Timeslots

= Maximum Number of Erlangs


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Frequency hopping

ParametersCA

Cell Allocation

MA

Mobile Allocation

MAIO

MA Index Offset

HSN

Hopping Sequence

Number


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Frequency hopping

ParametersGeneral parameters of the BTS, specific to

one BTS, and broadcast in the BCCH andSCH:

CA: Cell Allocation of radio frequency channels.

This is the allocation calculated when frequencyplanning


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Frequency hopping

ParametersGeneral parameters of the BTS, specific to

one BTS, and broadcast in the BCCH andSCH:

FN: TDMA Frame Number, broadcast in the SCH,in form T1,T2,T3'.

T1R: time parameter T1, reduced modulo 64 (6 bits)

T3: time parameter, from 0 to 50 (6 bits)



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Frequency hopping

ParametersSpecific parameters of the channel, defined

in the channel assignment message:

MA: Mobile Allocation of radio frequency channels

Defines the set of radio frequency channels to be usedin the mobiles hopping sequence.

The MA contains N radio frequency channels,

where 1 N 64.

Can be same as, or a subset of CA


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Frequency hopping

ParametersSpecific parameters of the channel, defined

in the channel assignment message:

MAIO: Mobile Allocation Index Offset.

(0 to N-1, 6 bits) ensures that TRXs using the same MAare using orthogonal frequencies

HSN: Hopping Sequence (generator) Number

(0 to 63, 6 bits) ensures that cells with the same MAand frame number are using different hopping

sequences


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Frequency hopping

Hopping sequence generationMA list contains N frequencies

if HSN = 0 (cyclic hopping) then:

MAI, integer (0 ... N-1):

MAI = (FN + MAIO) modulo N

The sequence just cycles through thefrequencies allocated to the TRX


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Frequency hopping

Hopping sequence generationif HSN = 1 to 63 then random hopping

Which frequency from Mobile Allocationdefined by MA Index (MAI)

The Hopping Sequence generation algorithm isprecisely defined in GSM 05.02 sec 6.2.3.

Frame Number

HSN

Generation

algorithm

MAI

MA

Frequency

if HSN = 0 (cyclic hopping) then:

MAI, integer (0 ... N-1) : MAI = (FN + MAIO) modulo N

else:

M, integer (0 ... 152) : M = T2 + RNTABLE((HSN xor T1R) + T3)

S, integer (0 ... N-1) : M' = M modulo (2 NBIN)

T' = T3 modulo (2 ^ NBIN

if M' < N then:

S = M'

else:

S = (M'+T') modulo N

MAI, integer (0 ... N-1) : MAI = (S + MAIO) modulo N

where:

T1R: time parameter T1, reduced modulo 64 (6 bits)



NBIN: number of bits required to represent N = INTEGER(log2(N)+1)

^: raised to the power of

xor: bit-wise exclusive or of 8 bit binary operands

RNTABLE: Table of 114 integer numbers, defined below:(see 05.02)


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Frequency hopping

Frequency planning

Approximately uniform traffic:

Same number of frequencies per cell

40% peak traffic load

30% average traffic load

Very non-uniform traffic:

Variable number of frequencies per cell?

Variable loading factor per cell?


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Frequency hopping

Frequency planning

Using the AFP

C/I Thresholds?

[Exercise: What median worst case C/I does aregular 1/3 reuse have?]

What worst case C/I?

For the interference matrix threshold

What total C/I?

For the verification plot of C/I?


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Frequency hopping

Frequency planningWith AFP

Trafficanalysis

Number offrequencies

per cell

Interference

matrix

Predictions

MLS arrays

Allocationalgorithm

C/I Thresholds

Frequencyplan

Trafficmap


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Frequency hopping

HSN planningHSN = 0 cyclic hopping

MA is repeated in the same order each cycle

HSN = 1 to 63 random hoppingHopping sequence 2 715 647 frames long

Transceivers on one site are distinguishedby different MAIOs

Therefore one HSN per site


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Frequency hopping

Cyclic or random hopping?

Cyclic hopping

Better fading diversity

Random hopping

Better interference diversity


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Frequency hopping

MAIO planning8 frequencies in MA list

Same 9 frequencies, same HSN butdifference of 1 in MAIO

351 2 4 9 7 6 8 1 5 3 42

346 5 1 8 7 9 2 6 4 3 152

9


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Contents

2. Repeaters







ParametersPlanning


Safety Guidelines



Health and

Environment


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Health and Environment

Power DensityThe power received per unit area (Watts per

square metre) at distance r (metres) from anisotropic source radiating power Pt (Watts)is

Since the area of a sphere surrounding thesource increases as the square of its radius,

then in an ideal case the power density fallsof as 1/(distance), the inverse square law.

24 r

PS t

=


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Power densityRadiation decay with distance

0

1

2

3

4

5

6

0 20 40 60 80 100 120 140

Range, metres

Watts/sqm

ICNIRP recommended limit


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Power density

Radiation decay with distance

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.22

0.24

0 10 20 30 40 50 60 70 80

Range, metres

Watts/sqm

1% of ICNIRP recommended limit


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Power Density

Transmitter radiating Power Pt

Transmit antenna with Aperture AetHuman standing distance r from Transmitter

Pt

r

TransmittingAntenna

Aet


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Power DensityFor a non-isotropic antenna the Gain Gt of

antenna with aperture Aet is

The power density in watts per square metreincident on a Human is

Where is the exposed cross sectional area of theHuman

ett AG 24

=

2

2

int 2)(

r

APWmP ett=tSGWmP =

)( 2int


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Power DensityOutput from a Mobile phone

The RF power density at a point 2.2cm from a 2W,900MHz phone and 1W, 1800 MHz phone has beenmeasured to be very roughly around 200 Watt/m

This is about one-quarter of the power density ofthe Suns radiation on a clear summers day.Although the frequency of emission is a million orso times smaller.

Exercise: Hands free kit at a distance of 50cm ?


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Power DensityOutput from a Base Station

The maximum intensity in the main beam at pointon the ground 50m from a 10m high Towercarrying a 120 sector antenna transmitting 60Watts has been measured to be about100milliwatt/m.

This power density of 100mW/m is very roughlyabout 2000 times smaller than that measured

2.2cm from the antenna of a mobile phone.


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Specific Absorption RateAbsorption is the result of conversion from

radio frequency energy to thermal energy,within an attenuating particle (e.g. bodytissue)

Radio frequency fields penetrate the body toan extent that decreases with increasingfrequency.

Incident Radio

Wave

Heat isdissipated


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Specific Absorption Rate

The rate at which the energy is absorbed bya particular mass of tissue m, is called theSpecific Absorption Rate (SAR)

For tissue mass m, the SAR = m/2

is the conductivity of the tissue (siemens/m))

is the density of the tissue (kg/m3)

is the rms value of the electric field (V/m)


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Values of

0.260.17Fat

1.641.11Muscle

0.450.25Bone

2.141.68Eye humour

2.271.86Blood

0.900.60Nerve

1900MHz800MHzTissue


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SAR is measured in Watts per Kilogram(W/Kg) and is highest from a phone heldclose to the head.

Maximum SAR from a 2W phone is less than1W/Kg, and in normal operation is typicallyhundreds of times lower.


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Health Research

The World Health Organisation (WHO) hasidentified further research required

Cancer

Current scientific evidence indicates thatexposure to RF fields emitted by mobile phonesand their base-stations are unlikely to induce orpromote cancers

Studies showing any link require very highradiation power in very small animals


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Health ResearchOther health risks

Reported effects on changes in brain activity,reaction times and sleep patterns. Effects aresmall and have no apparent health significance

Driving

Research has shown increased risk of trafficaccidents when using mobile phone when driving(either handheld or hands free kit)

Compare with

conversation with passenger

children fighting

talk show on radio


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Safety GuidelinesThe international body responsible for

advising on EMF exposure is theInternational Commission on Non-IonisingRadiation Protection (ICNIRP).


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Safety Guidelines

The average power absorbed by the wholebody should not exceed 0.08 W/kg(additional restrictions apply to particularparts of the body e.g. 2W/kg for the head).

These values will limit temperature rises in thebody to fractions of a C.

Recommendations are that the level of

electromagnetic fields should not exceedabout 4.5W/m (900MHz) or 9W/m (1.8GHz).


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Safety Guidelines

Measured and predicted base stationradiation at a distance of 50m is between300 and 3000 times less than the safetyguidelines.

Nevertheless a sensitive approach isrequired when dealing with concerned

residents.


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Contents

2. Repeaters







ParametersPlanning


Safety Guidelines



GPRS/EDGE


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GPRS/EDGE

Radio Access Network Technologies

GSM

GPRS

WCDMA

HSCSD

EDGE

57.6kb/s

14.4kb/s

115 kb/s

384kb/s

2Mb/s

Bit rate

(Theoretical)


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GPRS/EDGE

Packet ConceptsGSM inherently supports circuit switching

Connection-oriented for traffic channels

Tied radio resource concept

Call concept for services

Optimised for voice traffic

Low rates for data services

Voice and data on single TDMA bearer

Not supporting packet data traffic well

Resource utilisation problems

Cost issues Transmission speed drawbacks


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GPRS/EDGE

Packet ConceptsDriving forces of designing GPRS

Be a natural choice for the expected increase inmobile data communication

Attract new market segments

Improve competition with other mobile networksand radio based solutions

Re-use of already made investments

Efficient use of radio frequencies

Market requirements


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GPRS/EDGE

Packet ConceptsGPRS designed to support packet switching

technology

End-to-end packetised data transport

Efficient radio resource utilisation for data withdynamic sharing of radio resource between packetand circuit switching services

Resource and bandwidth on demand

Efficient support of bursty type applications

TS1GPRS

TS2TS1

TS3

Circuit Switched Data


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GPRS/EDGE

Packet ConceptsGPRS designed to support packet switching

technology

Variable peak data rates

Faster air access: multi-slot operation

Volume based charging possible only pay 4what u use

Supporting of existing data applications and opento new applications

Support for Point-to-Point, Point-to-Multipoint(PTM) Multicast and Point-to-Multipoint Group Call


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GPRS/EDGE

Packet ConceptsCircuit versus packet switching

Flexible (time, volume,flat rate, etc.)

Per time (but otheroptions possible, e.g. flat

rate)

Charging

At each packetAt set-up timeCongestion

Not requiredRequiredCall set-up

Different patches fordifferent packets

Information follows thesame route

Switching

Store-and-forwardAt time of origination

(without storage)

Transmission

EfficientPotentially wastedResource utilisation

DynamicFixedBandwidth allocation

NoYesDedicated link

Packet switchingCircuit switchingItem


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GPRS/EDGE

GPRS channelsPDCH - Packet Data Channel

Physical channel dedicated to packet datatraffic

optimised for packet data traffic

can carry data traffic, control channels or a mix

Master-Slave concept, i.g. packet common controlchannels


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GPRS/EDGE

GPRS ChannelsLogical structure of PDCHs

BCHBroadcast ChannelsDOWNLINK ONLY

PBCCHPacket Broadcast Control CH(can be combined with BCCH)

MS CONTINUOUSLYMONITORS

TCHTraffic Channels

PDTCHPacket Data TCH, one channel can be shared

by several active users.

GPRS Interface Logical Channels

PCCCHPacket Common Control

Channels(can be combined with CCCH)

PPCHPacket Paging CH

BSS WANTS TOCONTACT MS

PAGCHPacket Access Grant CH

PDCH ISALLOCATED TO MS

PRACHPacket Random Access CH

MS ASKS FORPDCHs.

DCCHDedicated Control

Channels

PTCCH

Packet Timing Control Channel.

PACCHPacket Associated Control CH

Allocated to the opposite direction than the PDTCHto which it is associated.

BCH

Broa

dcas

tChanne

ls

DOWNLINKONLY

PBCCH

Pac

ke

tBroa

dcast

Con

tro

lCH

(can

becom

bine

dw

ithBCCH)

MSCONTINUOUSLY

MONITORS

TCH

Tra

fficChanne

ls

PDTCH

Pac

ke

tDa

taTCH

,onec

hanne

lcan

bes

hare

d

bysevera

lact

iveusers.

GPRSInterfaceLogicalChannels

PCCCH

Pac

ke

tCommon

Con

tro

l

Channe

ls

(can

becom

bine

dw

ithCCCH)

PPCH

Pac

ke

tPag

ing

CH

BSSWANTSTO

CONTACTMS

PAGCH

Pac

ke

tAccess

Gran

tCH

PDCHIS

ALLOCATEDTOMS

PRACH

Pac

ke

tRan

dom

Access

CH

MSASKSFOR

PDCHs.

DCCH

D

edica

tedCon

tro

l

Channe

ls

PTCCH

Pac

ke

tTiming

Con

tro

lChanne

l.

PACCH

Pac

ke

tAssoc

iatedCon

tro

lCH

Alloca

tedtotheopposi

tedirec

tion

than

the

PDTCH

tow

hichitisassoc

iated

.


100/141



GPRS/EDGE

GPRS ChannelsPacket Broadcast Control Channels

GPRS specific broadcast can be made either onexisting BCCH or on PBCCH

full flexibility in allocating of broadcast resources

capacity on demand (long term basis)

PBCCH carriers all necessary GPRS systeminformation

facilities also circuit switched operation when GPRSattached

Existence and configuration of PBCCH isindicated on BCCH

Preferably, PBCCH is allocated on BCCH carrier


101/141


102/141



GPRS/EDGE

GPRS ChannelsPacket Dedicated Control Channels

PACCH

Packet Associated Control Channel

PTCCH/U

Packet Timing advance Control Channel, Uplink

Used to transmit RA burst

PTCCH/D

Packet Timing advance Control Channel, Downlink

Used to transmit TA updates to one or more MSs


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GPRS/EDGE

GPRS ChannelsPDTCH

Packet Data Traffic Channels

Carries RLC-data blocks


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GPRS/EDGE

Channel mapping52-Multiframe Structure for PDCHs

52 TDMA Frames

B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X

X = Idle frame

T = Frame used for PTCCH

B0 - B11 = Radio blocks


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GPRS/EDGE

Channel mappingPossible combination of PDCHs

PDTCH + PACCH + PTCCH

PCCCH + PDTCH + PACCH + PTCCH

PBCCH + PCCCH + PDTCH + PACCH + PTCCH

GSM Channels

BroadcastControl Channel

Dedicated CommonControl Channel

Traffic Channels

BCCHFCCHSCHPCHRACHAGCH

SDCCHSACCH

TCHSACCH

FACCH

SingleCarrier

GPRS Channels - Dynamic Allocation

BroadcastControlChannel

DedicatedCommonControlChannel

Traffic Channels - TCH

BCCH

FCCH

SCH

PCH

RACH

AGCH

SDCCH

SACCH

TCH

SACCH

FACCH

Packet DataChannel - PDCH

PDTCH

PACCH

SingleCarrier

Only allocate PDCH when required to transferGPRS Data or SignallingLOW TRAFFIC - share G SM common control channels

Typical Channel Resources For A GSM

Circuit Switched Only Network.

Dynamic GPRS PDCH Resources

(Low Traffic Levels)

GPRS Channels - Static Allocation

Combined PBCCH & PDTCH

Broadcast

ControlChannel

DedicatedCommonControl

Channel

Traffic Channels

BCCH

FCCH

SCH

PCH

RACH

AGCH

SDCCH

SACCH

TCH

SACCH

FACCH

Packet DataChannel - PDCH

PBCCH

PPCH

PAGCH

PRACH

PDTCH

PACCH

SingleCarrier

PBCCH and PDTCH exist on same TimeslotMEDIUM TRAFFIC - 1 Timeslot can handle allGPRS data and common control signalling

GPRS Channels - Static Allocation

Non Combined PBCCH & PDTCH

Broadcast

ControlChannel

DedicatedCommonControl

Channel

Traffic

Channels

BCCH

FCCH

SCH

PCH

RACH

AGCH

SDCCH

SACCH

TCH

SACCH

FACCH

Packet DataChannel- PDCH

PDTCH

PACCH

SingleCarrier

Packet

DataChannel

PBCCH

PPCH

PAGCH

PRACH

PBCCH and PDTCH exist on different TimeslotHIGH TRAFFIC - 2+ Timeslots handle allGPRS data and common control signalling

Combined PBCCH & PDTCH

(Static allocation)

Non-combined PBCCH & PDTCH

(Static allocation)

Examples of PDCH allocations on TDMA frame


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GPRS/EDGE

Core network enhancements

PSPDN

HLR

MSC

A

MAP-D

VLR

BSS

PSTN/

ISDN

Gb

Gr

Gs

SGSN

N.B. Gc & Gs interfaces are optional

Gc

Gn Gi

GGSN

C

CU

P

CU

SGSN - Serving GPRS SupportNode

MSC - Mobile Switching CentreVLR - Visitor Location Register

HLR - Home Location RegisterBSS - Base Station System

PSPDN - Packet Switched PublicData Network

GGSN - Gateway GPRS SupportNode

CCU - Channel Codec Unit

PCU - Packet Control Unit

MS

Core

Network


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GPRS/EDGE

Core NetworkGateway GPRS Support Node GGSN

It enables the access to packet services

Transport layer routing protocol support

PDU tunnelling

Screening

Data/packet counting

Address mapping, routing tables


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GPRS/EDGE

Core NetworkServing GPRS Support Node SGSN

It serves the MS and support the Gb and Iuinterfaces

Mobility Management (MM)

Ciphering

Compression

GSM circuit switched interactions

Data/packet counting


109/141



GPRS/EDGE

Core networkBSS part

Packet Control Unit PCUit converts the air interface protocols (MAC, RLC)and the protocols used towards the SGSN

PDCH scheduling functions for data transfer

error handling towards MS

channel access control functions, e.g. access request

and grants

radio channel management functions, e.g. powercontrol, congestion control, broadcast control

information, etc.


110/141



GPRS/EDGE

Core networkBSS part

Channel Codec Unit CCU

channel coding (FEC and interleaving)

radio channel measurements functions (received

quality level, received signal level and informationrelated to timing advance measurements)


111/141



GPRS/EDGE

MS Modes of Operation Class A

MS Attached to BOTH CS and GPRS

Full SIMULTANEOUS operation

1 time slot for CS + 1 or more for GPRS

Class B

Attached to BOTH CS and GPRS

Either/Or operation allowed

GPRS service placed in suspend mode whilst CS used

Class C

Attached to GPRS ONLY

Data Only PC card or vending machine card


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GPRS/EDGE

PDP context activationFor access to external data networks MS

must perform following procedures:

GPRS Attach network is inform of MS presence

GPRS PDP context activation to receive andtransmit of data packets

PDP Packet Data Protocol


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GPRS/EDGE

PDP context activationGPRS Attach

The mobile terminal asks core network to activatethe procedure. MS indicates its capability ofsupporting multi-slot operation, encryptionalgorithm and type of mode (CS, PS or both)

Authentication procedure is performed

Subscription information is exchanged betweenHLR and SGSN and MSC/VLR

SGSN sends confirmation message to MS


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GPRS/EDGE

PDP context activationGPRS PDP context activation

MS requests PDP context activation (addressassignment, QoS, etc.)

SGNS validates the request (with subscriptiondata from HLR)

SGSN determines the GGSNs address (based oninformation from MS and data from HLR)

A logical link between SGSN and GGSN isactivated (GTP tunnel)

SGSN requests an IP address allocation at GGSNand forward it to MS

Packet data transfer can be processed

PDP context activationGPRS PDP context activation

MS requests PDP context activation (addressassignment, QoS, etc.)

SGNS validates the request (with subscriptiondata from HLR)

SGSN determines the GGSNs address (based oninformation from MS and data from HLR)

A logical link between SGSN and GGSN isactivated (GTP tunnel)

SGSN requests an IP address allocation at GGSNand forward it to MS

Packet data transfer can be processed


115/141



GPRS/EDGE

Coding and modulationGPRS Physical Layer

Modulation and burst formatting unchanged

Block interleaving over 4 TDMA-frames (radioblock - smallest amount of data over the airinterface)

4 possible channel coding: CS-1,..., CS-4

CS1 (most robust) always used for controlsignalling


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GPRS/EDGE Coding and modulation

Why having several coding schemes? Optimise throughput for given radio conditions

00.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

C/I [dB]

Throughput[kBytes/s]

CS1

CS2

CS3

CS4

BLER=10%

(TU50 ideal FH)


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GPRS/EDGE

Coding and modulationGPRS coding schemes

109.613.717.59171.221.44281 (no coding)CS-4

80.810.112.93124.815.63123/4CS-3

70.48.810.79107.213.42682/3CS-2

46.45.86.8672.49.051811/2CS-1

Max truepeak user

throughput

rate for 8 TS[kb/s]

True peakuser

throughput

rate [kb/s]

Maximumuser

throughput

rate [kb/s]

Maximumraw user datarate for 8 TS

[kb/s]

Raw userdata rate

[kb/s]

Data bits perblock

Code rateCodingScheme


118/141



GPRS/EDGE

Coding and modulationGPRS coding schemes

Layers overhead reduces the throughput by up to83% of user data rate

Additional overhead for processing time, reactionon radio conditions, etc. reduces the throughputby up to 65% of user data rate


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GPRS/EDGE

Coding and modulationGPRS coding schemes performance

CS1 only gives the best overall throughput in extremeradio environments, with C/I < 4 dB

CS2 outperforms CS1 in all but the very harshest ofradio environments, above C/I 4dB

CS3 will provide a higher throughput than CS2 orCS1, in reasonably good environments, above aroundC/I 10dB

In poor radio conditions throughput differencebetween CS1, CS2 and CS3 is small


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GPRS/EDGE

Coding and modulationGPRS coding schemes performance

CS4 requires a good radio link and gives the bestthroughput above ~ 15-25dB C/I depending on theenvironment

Baseband SFH would be unlikely to change theperformance of CS3 and 4 as there is insufficientcoding to recover from one of the four bursts inerror

Higher coding schemes suffer severely in fastmoving environments


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GPRS/EDGE

Coding and modulationEDGE Enhanced Data Rate for GSM

Introduction of new coding schemes andmodulation (8-PSK)

ECSD: Enhanced Circuit Switched Data

EGPRS: Enhanced GPRS


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GSM evolution to EDGE

EDGE standardisation phases Phase 1

ECSD: rates up to 64 kbps 43 kbps per TS, average data rates expected 32 kbps

EGPRS: rates up to 473 kbps 8x59 kbps, average data rates expected 40 kbps per TS

Multicall: e.g. simultaneous voice and packet data calls

Phase 2 features candidates Rich voice and video calls QoS for EGPRS (IP)

More voice capacity - EDGE AMR

HiFi speech quality EDGE WB AMR

128 kbps ESCD ISDN 2B

Phase 3 features candidates Above 2 Mbps packet data user rates


123/141



GPRS/EDGE

Coding and modulationNew modulation 8-PSK

3 bits per symbol

Non-constant envelope high requirements forlinearity of power amplifier

Because of amplifier non-linearity, a 2-4 dB powerback-off is typically required

Symbol rate and burst length identical to those ofGMSK

(1,1,1)

(0,1,1)

(0,1,0)

(1,1,0)

(1,0,0)

(1,0,1)

(0,0,1)

(0,0,0)

8-PSK modulation

69.2 kbps22.8 kbpsGross rate / time slot

346 bits114 bitsPayload/burst

270.833 ksps270.833 kspsSymbol rate

8-PSK, 3 bits/symbolGMSK, 1 bit/symbolModulation

EDGEGSM


124/141



GPRS/EDGE

Coding and modulationECSD services and radio interface rates

HSCSD update for 8-PSK modulation, maximumuser rate still limited to 64 kbps/user

Same services as in HSCSD, but with less amount ofradio resources simpler mobile

E.g. 64 kbps service: 7 x 9.6 or 5 x 14.4, but 2 x 32 with ECSD

ECSD radio interface rates are 29 kbps, 32 kbps and

43.5 kbps


125/141



GPRS/EDGE

Coding and modulationECSD services and radio interface rates

43.569.28-PSK0.629E-TCH/F43.232.069.28-PSK0.462E-TCH/F32

29.069.28-PSK0.419E-TCH/F28.8

14.522.8GMSK0.64TCH/F14.4

12.022.8GMSK0.53TCH/F9.6

6.022.8GMSK0.26TCH/F4.8

3.622.8GMSK0.16TCH/F2.4

Radiointerfacerate [kbps]

Gross rate[kbps]

ModulationCode rateService


126/141



GPRS/EDGE

Coding and modulationEGPRS

9 new modulation and coding schemes(GPRS has 4, but an EDGE MS mustsupport all 13)

Mechanism to improve and maintain link quality

Link adaptation

Incremental redundancy

EGPRS: improved retry mechanism

Incremental redundancy reduces retry level by sending successive retrieswith different puncturing schemes, and soft-combining the received data.

E.g. if the first transmission of radio block fails, it is retransmitted withdifferent puncturing scheme (P1, P2, P3) and then soft combined with olddata. It gives approximately 2dB gain on average, but varies with MCSand BLER. The retry process by EGPRS is not restricted to the samecoding scheme (unlike to GPRS same coding scheme always used).When link adaptation has occurred within the same family, theretransmissions can be sent with the new coding scheme.


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GPRS/EDGE

Coding and modulationEGPRS

59.2A18-PSK9

54.4A0.928-PSK844.8B0.768-PSK7

29.6A0.498-PSK6

22.4B0.378-PSK5

17.6C1GMSK4

14.8A0.80GMSK3

11.2B0.66GMSK2

6.8C0.53GMSK1

User rate[kbps]

FamilyCode rateModulationMCS


128/141



GPRS/EDGE

Quality in a (E)GPRS networkCurrent GSM networks are deployed for

voice service

Hard criteria for speech service quality:

minimum signal level receiver sensitivity level

minimum signal to interference ratio C/I

Quality in a (E)CSD network is similar tospeech service quality hard criteria

Network Air User

File File

corrupted

File

corrupted

File

OK

File

Retransmission of erroneous radio blocks on air interface


129/141



GPRS/EDGE

Quality in a (E)GPRS networkQuality in a (E)GPRS network for packet data

services

TROUGHPUT - Retransmission of erroneous radioblocks

Function of received signal level and signalquality (C/I)

Block Error Rate BLER

TS_Throughput = TS_Peak_Throughput * (1 BLER)


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GPRS/EDGE

Coverage issuesFor fixed BLER: the higher modulation and

coding scheme the less coverage range less redundancy

For higher throughput per TS better signallevel is required, thus less coverage

Under poor radio condition the performanceof MSC1 is better then CS-1, thus signallingcoverage for EDGE is better then for

GSM/GPRS


131/141



GPRS/EDGE

Coverage issuesUnder excellent signal level CS-4 provides

more throughput per TS then MSC-4, butmuch less then MSC9

With incremental redundancy MSC1-9provide better or equal quality as CS1-4

Downlink diversity and incrementalredundancy allow MSC-5 in downlink toreach almost the same coverage range as

speech service Assumptions: incr_red gain: 2dB,

DL_div gain: 2dB, body loss gain: 3dB


132/141



GPRS/EDGE

Coverage issuesCoverage for 64 and 128 kbps services for

EGPRS

Benchmarks for system performance

Assuming: 3 TS mobiles, Incremental Redundancy

13dB C/(I+N) for 64 kbps (MSC-7 IR)

25dB C/(I+N) for 128 kbps (MSC-8 IR)

If a terminal can support more TSs, then reduced

C/(I+N) requirements


133/141



GPRS/EDGE

Frequency planning issuesHigher data rates require high C/I, typically

greater then 20dB for MSC-7 and MSC-8

Loose re-use patterns will provide optimumperformance for all load levels

For systems with very restrictive frequencyallocation, EGPRS can offer goodperformance even for very tight frequencyre-use patterns (1/3 or 3/9)

EGPRS traffic suited for BCCH use layerwith better C/I


134/141



GPRS/EDGE

Frequency hoppingLoss or gain dependant on techniques, C/I

and coding/modulation scheme

Baseband hopping

BCCH carrier can hop, but no BCCH TS restriction to multiple TSs usage (all TSs from onemobile require the same hopping group)

Synthesised hopping

BCCH cannot hop, no restrictions to multislot

mobiles as long no intracell HO


135/141



GPRS/EDGE

Capacity issuesAvailable capacity within of circuit-switched

capacity

Resource allocation for circuit switched servicesbased on Erlang B formula allows low blockingprobability, thus statistically some resources arenot used.

This capacity can be used for packet datatransmission, which can be temporally interruptedto accommodate CS traffic peaks, to guarantee no

quality loss of CS traffic E.g. 2 TRX configuration, 14 TCH, 2% GoS, CS

allowable load 8.2 Erlangs, on average 5.8 spare TCH


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GPRS/EDGE

Capacity issuesCapacity calculation for (E)GPRS

Throughput = #_(E)GPRS_TS *mean_data_rate_per_TS

(mean_data_rate_per_TS depends on C/I and S/Nperformance of different coding and modulationscheme)


139/141



GPRS/EDGE

Capacity issuesResource allocation

Example: 2 TRX cell

BCCHTRX 1

TRX 2

SDCCHSwitched

Territory

Packet

Switched

Territory

Dedicated

GPRS

Capacity

TS TS TS TS TS TS

TS TS TS TS TS TS TSTS

Territory border moves

Dynamically based onCircuit Switched traffic load

EGPRS: improved retry mechanism

Incremental redundancy reduces retry level by sending successive retrieswith different puncturing schemes, and soft-combining the received data.

E.g. if the first transmission of radio block fails, it is retransmitted withdifferent puncturing scheme (P1, P2, P3) and then soft combined with olddata. It gives approximately 2dB gain on average, but varies with MCSand BLER. The retry process by EGPRS is not restricted to the samecoding scheme (unlike to GPRS same coding scheme always used).When link adaptation has occurred within the same family, theretransmissions can be sent with the new coding scheme.


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gsm advanced v1-0 notes

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