ARQ Aware Scheduling

Integrating Link Adaptation, Packet Retransmission and Multi-user Scheduling

Link adaptation, packet retransmission and multi-user scheduling are three sub-layers in MAC that are heavily coupled. Link adaptation dynamically selects transmission rate based on channel state information. Deriving proper selection criterion is particularly difficult with a limited, coarse scale rate set. Overly conservative selection leads to under-utilization while overly aggressive suffers from overhead of frequent retransmissions. We derive a proper characterization of achievable throughput taking into account operations of different retransmission mechanisms and configuration of rate set. This enables joint optimization of rate selection and retransmissions to provide channel adaptation in finer granularity. We incorporate this throughput measure into the decision of multi-user scheduling to provide a proper assessment of user priority based on its channel quality and retransmission status. This work provides a systematic optimization of three inter-dependent sub-layers and leads to better resource utilization.

Optimizing ARQ Performance in High Speed Downlink Systems with Scheduling
Haitao Zheng, Harish Viswanathan
IEEE Trans. on Wireless Communications, vol. 4, iss. 2, March 2005, pp.495-506
[Abstract, PDF]

Slides: coming soon!
Haitao Zheng, April 16, 2005