An Efficient ARQ mechanism in Multi-Hop Relay Systems Based on IEEE 802.16 OFDMA

A Mobile Multi-hop Relay (MMR) Task Group was created to achieve coverage extension and throughput enhancement by introducing a relay station (RS) in the IEEE 802.16 system. If the RS is introduced in the 802.16 system, the reliability of data transmission is worsen, since data transmission failures occur more frequently due to several wireless links establishing end-to-end connection and an ARQ mechanism used in the 802.16 system is not optimized for multi-hop environment. In this paper, we propose an ARQ mechanism focused on the 802.16 MMR system. The proposed ARQ mechanism introduces a new ARQ feedback message made by the RS for fast and efficient data transmission. The numerical analysis and simulation results show that transmission delay is reduced and transmission efficiency is enhanced by the aid of the RS with the proposed ARQ mechanism.