Download - Coordinated Multipoint (CoMP) Transmission for LTE-Advanced Networks in Dense Informal Settlements
Coordinated Multipoint (CoMP)Transmission for LTE-Advanced Networksin Dense Informal Settlements
Beneyam B. Haile, Edward Multafungwa and Jyri HämäläinenDepartment of Communications and NetworkingSchool of Electrical Engineering, Aalto UniversityEspoo Finland
IEEE AFRICON 2013, Mauritius, September 11
OutlineØ MotivationØ Deployment scenarioØ CoMP criteria and schemeØ System simulation parameters and assumptionsØ Simulation resultsØ Conclusion
2
Motivation (1/2)Future mobile networks are expected to deliver consistentthroughput experience throughout the network
3
This is challenging in LTEnetworks due to varying desiredsignal strength, intercellinterference and cross-tierinterference across the network.
CoMP technology is considered as a candidate solution andit has recently been studied by academia and industry.
More challenging in denseinformal settlement area
Motivation (2/2)CoMP performance is evaluated in 3GPP release 11 assuming idealbackhaul
4
An ongoing work item on evaluation of CoMP performanceassuming practical backhaul is there in 3GPP release 12
Simulation works assume uniform cellular layout
This study evaluates performance ofa practical CoMP technique in anexamplary dense informal settlementarea considering terrain and 3Dbuilding information .
Deployment scenario in an example informalsettlement areaThree one-sectored macro celldeployed in Hanna Nasif area,Dar es Salaam, Tanzania
5
Hanna Nasif: around 40,000people/km^2, 3000 buldings
Users (LTE UEs) are droppedrandomly in the simulationarea.
Note: Instead of users, we canalso have hotspot nodes usingCoMP as a backhaul
CoMP criteria and scheme 1(2)Coordination is assumed among the three macro cells
6
CoMP criteria and scheme 2(2)
7
CoMP UEs are selected based on the average of the differencebetween received signal powers from cell 1 and cell 2, and cell 1and cell 3:
CoMP technique: Quantized Co-phasing (QCP), suboptimal andpractical (used in WCDMA/HSPA/LTE)
Where
System simulation parameters andassumptions
Parameter Values/AssumptionsAir Interface LTE FDDCarrier Frequency 2000 MHzSimulation Radio propagation modeling (WinProp)
Static system level simultion (Matlab)5 m resolution; 1.5 m prediction height
CoMP Three cooperating cellsDownlink JP CoMPQ-CP limited feedback with N = 3 feedbackbits
Macro Cells Cell 1 Cell 2 Cell 3Transmit Power 46 dBm 46 dBm 46 dBmAntenna Height 15 m 20 m 25 mAntenna Pattern Kathrein
741984Kathrein741984
Kathrein741984
Azimuth 140 0 250Intersite distance Approximately 500 mMean UE Number 20UE mobility Mobility off; Users distributed randomly in
the simulation area in each snapshotFading Shadow fading: Gaussian (0 dB mean, 8 dB
standard deviation), decorrelation distance50mFast fading: Zero mean complex Gaussian
Buildings Buildings of variable dimensionsBuilding heights 3-6 mBuilding benetration loss: 10 dB
8
3GPP guidlines are used
Average received power is computedusing dominant path model implementedin the WinProp propagation modelingtool
SINR performance result (1/2)
9
CoMP threshold (dB)1 3 6 10
0.5% 2.5% 15% 36%
The higher the CoMP threshold thelarger the number of CoMP UEshence, the better the overall SINRperformance
Percentage of CoMP UEs
One third of power transmission
At low CoMP thresholds (≤ 3dB), theoverall SINR performance improvementrelative to non-CoMP case is negligible
SINR performance result (2/2)
10
CoMP threshold (dB)1 3 6 10
0.5% 2.5% 15% 36%
The difference in transmission powershas very little impact on overall SINRperformance
Percentage of CoMP UEs
Full power transmission
Most of the SINR gain is achievedfrom avoiding the interferencesthan the Q-CP transmission technique
SNR gain performance result
11
CoMP threshold (dB)1 3 6 10
0.5% 2.5% 15% 36%
The best SNR gain performance isachieved for the smallest threshold,thus smallest power imbalance
Percentage of CoMP UEs
Full power transmission
Similar trends in SNR gains are notedthrough analytical studies
Spectral efficiency performance result (1/2)
12
Full power transmissionOne third of power transmission
The larger the CoMP threshold, the higher the overall spectral efficiencygains
Spectral efficiency gain performance result (2/2)
13
Full power transmissionOne third of power transmission
Energy efficiency gains are possible for one third power transmissionwithout considerable reductions in spectral efficiency gains
The smaller the CoMP threshold, the higher the CoMP UE spectralefficiency gains
ConclusionsCoMP enhancements is a viable option for throughputenhancements in LTE networks that are being deployed in denseurban areas
14
The higher the threshold, the larger number of CoMP enabledUEs but smaller spectral efficiency gains for CoMP UEs
Tradeoff between energy efficiency and spectral efficiency canbe managed through optimal selection of transmission power ofcooperating nodes.
Future research: further study of energy-efficiency trade-off,CoMP in HetNets in densely populated area, CoMP as a backhaulof small cells and relays.
15
Thank you for your kind attention!
Further info:Beneyam Haile (Doctoral Researcher) and Edward Mutafungua (PostDoctoral Researcher)Aalto UniversitySchool of Electrical EngineeringDepartment of Communications and NetworkingOtakaari 5A, Espoo, [email protected] and [email protected]: +358 44 2108323 and +358 40 733 3397
16
Support Slides
Why Focus on Informal Settlements?• Focus of on informal settlements (slums) in suburban/urban areas
– Emerging markets have fastest slum growth rates; 30-50% of globalurban population in 2030 (UN HABITAT 2007)
– Characterized by very high population density (>4000 people/sq km)and low income (1-3 USD/day)
– Underserved: Limited access to key services (electricity, sanitation,healthcare, broadband etc.)
Kibera, Nairobi, Kenya(pop. 230000 – 1 million, area 2.5 sq km)
Korail, Dhaka, Bangladesh(pop. 120000, area 0.4 sq km)
Dominant path model• Dominant Path Model
– Faster computation time than ray tracing models– Models dominant path between TX and RX pixel– More accurate than COST 231 model in scenarios with strong multipath
propagation– Combination of urban and indoor predictions possible (CNP mode).
• Urban Dominant Path Model (UDP) for outdoor• Indoor Dominant Path Model (IDP) with a higher resolution for indoor• Potentially good choice for urban or densely built suburban scenarios, particularly for
cases with below rooftop transmitters (small cells)
Comparison of different approaches(COST 231, Ray Tracing, DPM)
Average received power map
Qiantized co-phasing