LTE Radio Planning and Optimisation
Contents
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LTE Radio Planning Basics LTE Link Budgets LTE Capacity Planning Optimisation Introduction Self Organising Network Concepts
Radio Planning Basics
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High Level Design Life Cycle
How many eNBs to satisfy objectives? • Capacity How many sites • Coverage available?
Pre-Build Optimisation Ensure CAPEX Efficiency and optimal performance Objectives satisfied with available sites?
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8
Information Required – Phase 1 Generally Known Data Frequency Band Amount of Allocated Spectrum Channel Bandwidth Equipment Performance Market Research Data Service Area Population Density Population Demographic Population Penetration Expected level of service
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LTE Link Budgets
Link Budget :– System Gain EiRP GDiv TxPA
GAnt
LF+C
Sys Gain GAnt IRLmin
UE Rxth
Sys Gain
= (TXPAUE + GAntUE) – (RxTHeNB + LeNB – GANTeNB – GDiv)
Sys Gain
= (TXPAeNB – LeNB + GAnteNB + GDiv) – (RxTHUE – GANTUE – GDiv)
UL
DL
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LF+C
2
Sys Gain
Link Budget : – MAPL, Spending the Budget
MAPL
Distance
Body Margin 0 – 3 dB
Building Margin 5 – 30dB
Fade Margin 8 – 12 dB
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Using MAPL to Find Distance
MAPL Antenna Height
Frequency
Clutter
Propagation Model
Distance 8
Terrain
Performance KPIs Signal Strength
Noise and Interference
64QAM
16QAM
QPSK
• • • • • • • 9
Cell Edge Throughput RSRQ RSRP RSSI SNR Area Availability Cell Edge Availability
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Defining RSRP, RSSI and RSRQ
Rs
Rs
Rs
Rs
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LTE Resource Block
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UE Radio Measurements
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15
RSRP and RSRQ Targets
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LTE Capacity Planning
Capacity in LTE
LTE supports Adaptive Modulation and Coding Actual Capacity will depend on users location in the cell SINR is the most important planning KPI Average cell throughput will lower than quoted maximums
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The Capacity Planning Problem
100+ Mbps! Assumes good radio signal in every part of the radio cell
64QAM
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16QAM
QPSK
User Distribution in the Cell
User Distribution will impact average cell throughput The resource scheduler in the eNB is very important Scheduling may be different between vendors
64QAM
16QAM
~10% of Area
~15% of Area
~75% of Area 16
QPSK
Mbps
Average Cell Throughput Lower Average Due to resource sharing Between many users
Higher Peak Loads due to less active users
time
Average Busy Hour Throughput
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Average Non-Busy Hour Throughput
Capacity Modelling
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Try to Determine what data the typical user will consume
Capacity Modelling cont.
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Extrapolate consumption between subscriber population Make assumptions about “busy period” to obtain Data Density
Capacity Modelling cont.
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Use Link Budget and Sector Throughput to determine number of radio cells
Optimisation Introduction
1
Optimisation Context
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Optimisation Targets
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Cell Edge Throughput RSRQ RSRP SNR Area Availability Cell Edge Availability
5-10Mbps -7dB -75dB >13dB 90% 75%
RF Optimisation Options – Antenna Orientations, Tilt, Azimuth – Transmit Power – Antenna Height – eNB Location
Mobility Optimisation
Initial Cell Selection
Qrxlevmeas
Low Qrxlevmin Qminoffset UE
High Qrxlevmin Qminoffset
Srxlev = Qrxlevmeas – (Qrxlevmin+ Qrxlevminoffset) - Pcompensation 24
No Search
Snonntrasearch
IRAT Search
Sintrasearch
LTE Search
Cell Reselection
Rs = Qmeas_s +Qhyst Rn = Qmeas_n + Qoffset
Rn > Rs > Treselection 25
Other Mobility Considerations
IRAT Cell Reselection Decisions UMTS LTE UE
GERAN
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• • • • •
Measurement Thresholds Cell Priority Mobility Offset/Hyst Mobility Status (speed) Cell Ranking
Other Mobility Considerations :- Handovers
LTE and IRAT Handovers UMTS LTE UE
GERAN
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• Measurement/ Reporting Thresholds • Cell Priority • Mobility Offset/Hyst • Mobility Status (speed) • Cell Ranking • eNB makes H/O Decision • H/O Algorithm Vendor/ Operator Controlled
Self Organising Network Concepts
Optimisation for Future Deployments
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Self Organising/Optimising Networks
SON Release 8 Focus is on initial equipment installation and integration eNB Self Configuration
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Automatic Inventory Automatic Software Download Automatic Neighbour Relation Automatic Physical Cell ID assignment
SON Release 9 Provides SON functionality covering operational aspects of already commercial networks, in particular key aspects related to network optimization procedures.
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Mobility Robustness/Handover optimization RACH optimization Load Balancing optimization Inter-Cell Interference Coordination
SON Release 10 Provides a richer suite of SON functions for macro and metro networks overlaid on and interoperating with existing mobile networks.
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Coverage & Capacity optimization Enhanced Inter-Cell Interference Coordination Cell Outage Detection and Compensation Self-healing functions Minimization of Drive Testing Energy Savings
SON Architecture
Centralised SON
A centralized architecture approach can be used for deploying real-time SON functions, such as Automatic Neighbor Relations and Automatic Physical Cell ID. The OAM must also handle large amounts of data in order to make the localized SON decisions across the network Multi-Vendor support may be difficult
SON eUTRAN
eUTRAN
OAM
EPC eUTRAN
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SON Architecture
Distributed SON
The distributed architecture leverages smart, autonomous network elements with local SON decision making This reduces the complexity, footprint and availability requirements of the OAM X2 requirements are more complex Easier in a multi-vendor system
SON
eUTRAN
SON
eUTRAN
OAM
EPC
SON eUTRAN
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SON Architecture
Hybrid SON
More complex solution OAM can make long term optimisation decisions and eNB can deal with the real time optimisation of load and interference Should be possible to build effective systems in a multi-vendor system
SON
SON eUTRAN
SON
eUTRAN
OAM
EPC
SON eUTRAN
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LTE Training:- Telecoms Academy
Visit Helen Robinson on Stand 23
LTE Technical and non-Technical Overviews LTE Radio Planning and Optimisation LTE Core Network Planning and Dimensioning eUTRAN Protocols and Signaling LTE and IMS miniMBA with LTE Focus Distance Learning Course with LTE focus
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Telecoms Academy
[email protected] http:// www.telecomsacademy.com http://www.schooloflte.com/ 37
