1. Arif Otyakmaz, ComNets, RWTH Aachen University 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, 21.11.2008 15 th FFV Workshop 15 th FFV Workshop

2. 2 Arif Otyakmaz, ComNets, RWTH Aachen University 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. 3 Arif Otyakmaz, ComNets, RWTH Aachen University Introduction and Motivation WRC 2007 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 10) –IEEE 802.16m (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 2 relaying for capacity enlargement and coverage extension Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion

4. 4 Arif Otyakmaz, ComNets, RWTH Aachen University Duplex Schemes 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 TDD FDD time guard band DL UL frequency HFDD Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion

5. 5 Arif Otyakmaz, ComNets, RWTH Aachen University WINNER MAC Frame and Relaying “ UT ” “ BS ”“ UT ”“ BS ” frame “ UT ” f t BS UT RN RUT hop1 hop2 relay link feeder link Relay Nodes (RN) change “task” on frame basis “BS task” on 2 nd hop: Supplying associated Remote User Terminals (RUT) on resources assigned by the BS by means of so called “resource partitioning “UT task” on 1 st hop: “Fed” by supplying Base Station (BS) Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion

6. 6 Arif Otyakmaz, ComNets, RWTH Aachen University Concept for Relay Capable Combined Full-/Half-Duplex FDD Map Data BS UT Half- Duplex Group 1 RN UL DL frequency 2 1 1 2 2 1 1 2 2 1 1 2 2 1 1 2 02176354 framenumber / time UL DL frequency 2 1 1 2 2 1 1 2 2 1 1 2 2 1 1 2 02176354 framenumber / time UL DL frequency UT BS UT BS UT BS UT BS 02176354 framenumber / time UL DL frequency 1 2 2 1 1 2 2 1 02176354 framenumber / time Remote UT Half- Duplex Group 1 Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion

7. 7 Arif Otyakmaz, ComNets, RWTH Aachen University Single-Hop Scenario: One BS, one FD-UT, one HD-UT Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion FD UL FDHD UL FD HD Saturation of full-duplex and half-duplex UT Frame NFrame N+1 Frame NFrame N+1 Full-Duplex UT below saturation

8. 8 Arif Otyakmaz, ComNets, RWTH Aachen University Representative Multi-Hop Scenario Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion Single-HopMulti-Hop Full-Duplex FDD Half-Duplex FDD Group 1 Group 2

9. 9 Arif Otyakmaz, ComNets, RWTH Aachen University Resource Partitioning between BS and RN Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion DL UL “BS” “UT” RN “task”

10. 10 Arif Otyakmaz, ComNets, RWTH Aachen University Uplink Throughput Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion Stateless/memoryless scheduler: Round-Robin Stateful scheduler: Proportional-Fair UL throughput per station [Mbit/s] Total offered UL cell traffic [Mbit/s] x10

11. 11 Arif Otyakmaz, ComNets, RWTH Aachen University Proportional Fair: History Weight Parameter Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion x10 Total offered UL cell traffic [Mbit/s] UL throughput per station [Mbit/s] Total offered UL cell traffic [Mbit/s] UL packet delay [s] Enlarging “history weight” parameter to 0.99 leads to fairness in terms of throughput between the different UT types

12. 12 Arif Otyakmaz, ComNets, RWTH Aachen University Conclusion Overview – Introduction – Duplex – System– Concept - Simulations - Conclusion “Proof of Concept” for relay capable combined full-/half- duplex FDD A memoryless scheduler –leads to unfair capacity share between half- and full-duplex UTs. –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 UTs 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. 13 Arif Otyakmaz, ComNets, RWTH Aachen University Thank you for your attention ! Arif Otyakmaz aoz@comnets.rwth-aachen.de