radio nw planning
TRANSCRIPT
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March 9, 2000 Copyright: Jaakko Lhteenmki1INFORMATION TECHNOLOGY
Jaakko LhteenmkiVTT Information Technology
P.O. Box 1202, FIN-02044 VTT, Finland
Tel: +358 9 4566547Fax: +358 9 4567013
E-mail: + [email protected]
Optimising Next Generation Mobile NetworksICM Conference 9-10 March 2000
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March 9, 2000 Copyright: Jaakko Lhteenmki2INFORMATION TECHNOLOGY
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March 9, 2000 Copyright: Jaakko Lhteenmki3INFORMATION TECHNOLOGY
Radio network planning =Determination of- cell locations- cell antenna types and pointings- carrier frequencies and- system parameterswith the objective of meeting the requirements for
capacity and quality of service (QoS)
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2000 2001 2002
General PacketRadio Service
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High-Speed Circuit-
Switched Data
0
XOWLSOHWLPH
VORWVIRURQHXVHU
1HZUDGLRLQWHUIDFH
Universal MobileTelecommunications System
Enhanced Data Modulationfor GSM evolution
1HZPRGXODWLRQ
WHFKQLTXH
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March 9, 2000 Copyright: Jaakko Lhteenmki5INFORMATION TECHNOLOGY
3-fold data-rate increase by 8-PSK modulation
Higher received signal level requiredDecreased service area
Increased offered trafficImproved data transmission
Packed-mode transmission New traffic models
Higher power threshold in planning
, or
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March 9, 2000 Copyright: Jaakko Lhteenmki6INFORMATION TECHNOLOGY
Several radio interfaces are being harmonised and willincluded in global IMT-2000 standard by the ITU:
CDMA TDD
TDMA
TDMA & FDMA
CDMA direct spread
CDMA multi carrier
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Multi-rate services to be taken into account Frequency planning not needed
Resource allocation carried out by controlling cell
density and parameters Macro-diversity and soft handover
Adaptive antennas
Important effect of channel impulse response
Multi-user detection (MUD)
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March 9, 2000 Copyright: Jaakko Lhteenmki8INFORMATION TECHNOLOGY
Start
Offered traffic density
Estimated cell capacity
Required cell density
Code planning
Parameter planning
Network simulation
Result analysis
Link-level performance
Coverage planning
no
yesStopNew iteration OK?
Focus of the presentation
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March 9, 2000 Copyright: Jaakko Lhteenmki9INFORMATION TECHNOLOGY
The performance of the up-link and down-linkconnection is evaluated by simulation.
Performance is characterised e.g. by SIR - BER (1 curve
(1 Signal to Interference Ratio - Bit Error Ratio
Simulations for different conditions- radio channel and interference conditions
- receiver types- transmission rates and modes
Usage of results
- product development- receiver threshold values for subsequent planningsteps (network simulation)
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datasource
base-bandprocessing
modulation RFparts
RFparts
demodu-lation
base-bandprocessing
compare
+
radiochannel
performance results: BER, FER, ...
- coding- interleaving- spreading
- de-spreading- de-interleaving- decoding
TRANSMITTER
RECEIVER
interferingsignals
delayamplitudeimpulse response
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March 9, 2000 Copyright: Jaakko Lhteenmki11INFORMATION TECHNOLOGY
Simulated impulse responsesequence (microcell conditions)
01000
2000 3000 4000
50006000
0
10
20
30
40
50
60
-150
-100
-50
delay(ns)
time(s)
amplitude(dB)
Channel model describes the effects experienced bythe signal propagating from transmitter to receiver
Simulated impulse response(open office environment)
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March 9, 2000 Copyright: Jaakko Lhteenmki12INFORMATION TECHNOLOGY
Parameters:
- WCDMA downlink
- chip rate 3.84 Mchips/s- 10 samples per bit- channel model: 6 tapsmicrocell (pedestrian)
- spreading code:OVSF, length 128
- scrambling code:complex Gold
- pulse shaping:
RRC, roll-off 0.22- simulation time: 8 s
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March 9, 2000 Copyright: Jaakko Lhteenmki13INFORMATION TECHNOLOGY
Carried out by using coverage prediction tools
Accurate coverage prediction calls for sophisticatedpropagation models
Specific models for different environments
Indoorand urban areas are most important, because of- high user density
- concentration of high data-rate usersAccurate indoor and urban area coverageprediction is needed
Find base station locations in accordance withcoverage and cell-size requirements
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March 9, 2000 Copyright: Jaakko Lhteenmki14INFORMATION TECHNOLOGY
Received power is a combination of the direct pathand dominant (first order) reflections and diffractions
++= 10101010 101010log10][difrefdir
PPP
r dBmP
= received power along direct path [dBm]dirP= received power along reflected paths [dBm]
refP
= received power along diffracted paths [dBm]difP
Pdir , Pref and Pdif calculated from expressionstaking into account empirical values of wall
transmission and reflection losses (see [2] for details)
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0 100 200 300 400 500-85
-80
-75
-70
-65
-60
-55
-50
Measured (Average 21 pts) Calculated (Average 21 pts)
Point Number
Power[dBm]
Statistics
Mean Error: -2.17
RMS Error: 3.13
Received Power vs. Measurement Point
d:\anetra\antenni1\\t0107.dat
1
2 3
4
5
Measured and predicted results in office building. Pictures from theNPS/i tool (Nokia) user interface.
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Office coverage predicted for two cases at1800 MHz to find optimum antenna location.
Antenna at centre of wall Antenna at corner
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Full 3D ray-tracing
Multiple reflections from building walls and terrain
Penetration into buildings through walls
Multiple diffraction around streetcorners and rooftops
Diffraction around terrain
undulations
Examples of direct,reflected and diffractedpaths from transmitterto coverage area pointsRX1..RX3
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BS
Example ofmicrocellcoverage areapredicted byMCT tool
(Sonera Oyj)
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March 9, 2000 Copyright: Jaakko Lhteenmki19INFORMATION TECHNOLOGY
1) Predict coverage areas for all potential BS sites andantenna installation options taking into account thedesired average cell-size
2) Find out the optimum combination of coverageareas giving the best area coverage with thespecified number of BS sites.
Optimisation carried out by using Genetic Algorithms:- individual = one combination of BS sites andantenna installations
- population = a group of individuals
- iterative search for best individual- at each iteration new individuals derived from thepopulation by using the GA- operations
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March 9, 2000 Copyright: Jaakko Lhteenmki20INFORMATION TECHNOLOGY
More information: K. Lieska, E. Laitinen, J. Lhteenmki, FrequencyAllocation with Genetic Algorithms, Proc. of the PIMRC99, Osaka, Sept.12-15, 1999.
Service area: city centre3x4 km
Potential BS sites: 70 Pixels: 120000
Allowed BS sites: 27
Results
- 99% of best possiblecoverage reached in< 100 iteration steps
Co
veragepoints(x1
000)
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Start
Initialise network
Move users
Calculate SIR
Execute power control algorithm
Stop/initiate connections
Generate simulation environment
noyesStop
Execute handover algorithm
Continue?
SIR = signal to interference ratio
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March 9, 2000 Copyright: Jaakko Lhteenmki22INFORMATION TECHNOLOGY
Generate simulation environment
Retrieve Information from link-levelsimulation
Number of subscribers per area
Traffic, service and mobility profiles
Required QoS for each service
BS locations and parameters
Predicted coverage information
System parameters
Initialise network
Locate BS-MS connections on map
Use predicted coverage areas forevaluation of up-link and down-linkSIR
Calculate SIR
Execute handover algorithm
Carry out handover if necessary
Execute power control algorithm
Change transmit powers if required
Stop / initiate connections
According to statistical distributions:- stop existing connections- initiate new connections
New iteration / stop
If simulation time has not beencompleted, start new simulation
iteration
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March 9, 2000 Copyright: Jaakko Lhteenmki23INFORMATION TECHNOLOGY
Blocking rate. The probability that a call can not beestablished when requested.
Call dropping rate. The probability that a call isinterrupted.
Quality of Service (QoS). Includes different issues fordifferent services. For example, in packet services
the packet throughput and packet delay are mostimportant.
Power level statistics. The proportion of different
power levels used at MS and BS. Handover rate.
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March 9, 2000 Copyright: Jaakko Lhteenmki24INFORMATION TECHNOLOGY
Overview on planning aspects 3G systems has beengiven with emphasis on link-level and networksimulation as well as coverage prediction.
Link-level simulation reveals basic performance of thesystem for different radio channel conditions andprovides input formation for other planning steps.
Coverage planning takes advantage of specific indoorand outdoor propagation models to meet highprediction accuracy requirements
Network simulation predicts the performance of thenetwork
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March 9, 2000 Copyright: Jaakko Lhteenmki25INFORMATION TECHNOLOGY
[1] T. Ojanper, R. Prasad, Wideband CDMA for third
generation mobile communications, Artech House,1998.
[2] E. Damosso, L. Correia, Digital mobile radio towards
future generation systems, European Commission,
Directorate General XIII, Belgium, 1999.
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CDMA Code Division Multiple Access
DECT Digital European Cordless Telecommunications
EDGE Enhanced data modulation for GSM Evolution
ETSI European Telecommunications Standards Institute
FDD Frequency Division duplex
FDMA Frequency Division Multiple Access
GPRS General Packet Radio Service
HSCSD High-Speed Circuit Switched Data
ITU International Telecommunications Union
SIR Signal to Interference Ratio
TDD Time Division Duplex
TDMA Time Division Multiple Access
UMTS Universal Mobile Telecommunications System
UTRA UMTS Terrestiral Radio Access
WCDMA Wideband Code Division Multiple Access