gsm advanced v1-0 notes
TRANSCRIPT
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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
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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
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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)
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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
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Repeaters
ApplicationsClosing small coverage gaps
Coverage
dimensionedfor rural
Some suburbanvillages not covered
Local repeatersclose the gaps
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Repeaters
ApplicationsProviding in-building coverage
Coveragedimensionedfor outdoors
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Repeaters
ApplicationsProviding line coverage, area coverage
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Repeaters
Types of repeaterBand selective / channel selective
905 MHz 915 MHz
40 dBm
0 dBm
Band selective
Channel selective
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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
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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
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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)
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Repeaters
Neighbour definitions
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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.
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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
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
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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
Propagation Model Tuning
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
Propagation Model Tuning
Area ofmeasurement
points
Remove measurementswith Path Loss > X
Remove measurementswith Path Loss < X
Regression slope
True slope
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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
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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Propagation Model Tuning
Effective height algorithmsSlope
( ) slopembeff dkHHH = slopeandslopedefine minmax:
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Propagation Model Tuning
Effective height algorithmsAverage
[ ]=
=n
i
profileeff ihH0
)(
A: Start Point B: End Point
pixelsize
ddnwhere AB
=
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Propagation Model Tuning
Effective height algorithmsDifference
Hb
Ho
Heff
Define max and min Heff
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Contents
2. Repeaters
IntroductionLink BudgetFeedback
Time DelayRF over fibre
38. Propagation Model Tuning
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)
T2: time parameter, from 0 to 25 (5 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)
T3: time parameter, from 0 to 50 (6 bits)
T2: time parameter, from 0 to 25 (5 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
IntroductionLink BudgetFeedback
Time DelayRF over fibre
38. Propagation Model Tuning
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
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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Health and Environment
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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Health and Environment
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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Health and Environment
Power Density
Transmitter radiating Power Pt
Transmit antenna with Aperture AetHuman standing distance r from Transmitter
Pt
r
TransmittingAntenna
Aet
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Health and Environment
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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Health and Environment
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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Health and Environment
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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Health and Environment
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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Health and Environment
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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Health and Environment
Specific Absorption Rate
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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Health and Environment
Specific Absorption Rate
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 and Environment
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 and Environment
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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Health and Environment
Safety GuidelinesThe international body responsible for
advising on EMF exposure is theInternational Commission on Non-IonisingRadiation Protection (ICNIRP).
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Health and Environment
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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Health and Environment
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
IntroductionLink BudgetFeedback
Time DelayRF over fibre
38. Propagation Model Tuning
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
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
.
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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
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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
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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.
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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)
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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)
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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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