MAC Performance Evaluation of IEEE 802.16j

Being an evolution of IEEE 802.16e, IEEE 802.16j mobile multi-hop relay (MMR) is proposed to gain coverage extension and throughput enhancement. Although the IEEE standard 802.16j-2006 has not been published yet, the second version of 802.16j Draft Standard (802.16j D2) has been released in 2007. In this paper, for the first time, we evaluate the MAC performance of the Draft Standard based on the new relay-based OFDMA frame structure and the new transmission technique-Tunnel. Transmission using tunnel has been defined in 802.16j D2, but our work is to find a way to make use of the tunnel to meet each connectionpsilas QoS requirement as well as gaining a higher MAC efficiency. The impact of different parameters, such as MAC frame size, MAC protocol data unit (MPDU) size, QoS and the number of connections are considered in our analysis. Our results show that, for the sake of 5 kinds of QoS defined in the standard, we suggest 5 tunnel CIDs should be included in each relay station (RS) to aggregate all the connections into 5 different groups. And our results also show that, hop by hop tunnel establishing has a better performance than end to end tunnel establishing. As confirmed by our performance evaluation, we recommend hop by hop tunnel establishing with 5 QoS differentiation which has the best MAC efficiency to apply in 802.16j network.