A class of adaptive hybrid ARQ schemes for wireless links

Wireless links are known to suffer location-dependent, time-varying, and bu rsty errors. This paper considers a class of adaptive error-control schemes in the data link layer for reliable communication over wireless links in w hich the error-control code and the frame length are chosen adaptively, bas ed on the estimated channel state/condition. Three error-control schemes ar e considered according to: 1) the number of code segments a packet is divid ed into and 2) the way a lost packet is retransmitted. Through throughput p erformance and computation complexity analyses, these three schemes are com pared, and then one of them is claimed to be the most attractive in terms o f computation complexity and practicality even though its throughput perfor mance is not the best. The simulation results also verify that this scheme works well over a time-varying fading channel. Error control for the medium access control (MAC) header and its effect on the performance of each erro r-control scheme are also considered since, without proper error protection for the header, it would be futile to exercise error control on the user d ata.