Half- and Full-Duplex FDD Operation in Cellular Multi-Hop Mobile Radio Networks

Transcription

1 5 th FFV Workshop Half- and Full-Duplex FDD Operation in Cellular Multi-Hop Mobile Radio Networks Arif Otyakmaz, Rainer Schoenen Department of Communication Networks RWTH Aachen University, Germany FFV Workshop,..008

2 Overview Overview Introduction Duplex System Concept - Simulations - Conclusion Introduction and Motivation Duplex Schemes in Mobile Radio Networks WINNER MAC frame structure Concept for Relay Capable Combined Full-/Half-Duplex FDD Simulation Scenarios and Results Conclusion

3 Introduction and Motivation Overview Introduction Duplex System Concept - Simulations - Conclusion WRC 007 frequency bands identified for IMT- Advanced systems ITU-R published invitation for submission of proposals for candidate IMT-Advanced systems Likely candidates (among others): 3GPP LTE-Advanced (Release 0) IEEE 80.6m (WiMAX) IST WINNER and Celtic WINNER+ projects To provide scalability and adaptivity candidate systems are based on OFDMA support FDD and TDD integrate Decode-and-Forward layer relaying for capacity enlargement and coverage extension 3

4 Duplex Schemes Overview Introduction Duplex System Concept - Simulations - Conclusion Time Division Duplex (TDD) Able to adapt the DL and UL phases according to the data service Switching between DL and UL needs guard times to avoid interference Larger cells lead to larger guard times Practical for metropolitan area environments Frequency Division Duplex (FDD) No need for guard times due to different radio resources in DL and UL Not able to adapt to different data services like TDD Higher cost of manufacture Practical for wide area environments Half-duplex FDD (HFDD) Cheaper alternative to full-duplex FDD frequency DL guard band UL TDD FDD HFDD time 4

5 WINNER MAC Frame and Relaying Overview Introduction Duplex System Concept - Simulations - Conclusion f frame RN Relay Nodes (RN) change task on frame basis task on nd hop: Supplying associated Remote User Terminals (R) on resources assigned by the by means of so called resource partitioning task on st hop: Fed by supplying Base Station () t R 5

6 Concept for Relay Capable Combined Full-/Half-Duplex FDD Overview Introduction Duplex System Concept - Simulations - Conclusion Half- Duplex Group frequency DL UL framenumber / time frequency DL UL Map framenumber / time RN Data frequency DL UL framenumber / time Remote Half- Duplex Group frequency DL UL framenumber / time

7 Single-Hop Scenario: One, one FD-, one HD- Overview Introduction Duplex System Concept - Simulations -Conclusion Saturation of full-duplex and half-duplex UL FD FD HD Frame N Frame N+ Full-Duplex below saturation UL FD HD Frame N Frame N+ 7

8 Representative Multi-Hop Scenario Overview Introduction Duplex System Concept - Simulations -Conclusion Single-Hop Multi-Hop Full-Duplex FDD Half-Duplex FDD Group Group 8

9 Resource Partitioning between and RN Overview Introduction Duplex System Concept - Simulations -Conclusion RN task DL UL 9

10 Uplink Throughput Overview Introduction Duplex System Concept - Simulations -Conclusion Stateless/memoryless scheduler: Round-Robin Stateful scheduler: Proportional-Fair x0 x0 UL throughput per station [Mbit/s] UL throughput per station [Mbit/s] Total offered UL cell traffic [Mbit/s] Total offered UL cell traffic [Mbit/s] 0

11 Proportional Fair: History Weight Parameter Overview Introduction Duplex System Concept - Simulations -Conclusion x0 UL throughput per station [Mbit/s] UL packet delay [s] Total offered UL cell traffic [Mbit/s] Total offered UL cell traffic [Mbit/s] Enlarging history weight parameter to 0.99 leads to fairness in terms of throughput between the different types

12 Conclusion Overview Introduction Duplex System Concept - Simulations - Conclusion Proof of Concept for relay capable combined full-/halfduplex FDD A memoryless scheduler leads to unfair capacity share between half- and full-duplex s. can lead to waste of / unused resources. In multi-hop scenarios this unfairness intensifies. A stateful scheduler guarantees scheduling fairness over multiple frames and so solves before mentioned problems. Scheduler strategy Proportional-Fair is sufficient. Multi-hop operation demands sophisticated coordination Considering number of remote s already during scheduling for first hop Balance between resource partitioning for second hop and scheduling for first hop Cognitions directly applicable to LTE and WiMAX

13 Thank you for your attention! Arif Otyakmaz 3