Aggregation and concatenation in IEEE 802. 16j mobile multihop relay (MMR) networks

The new mobile multi-hop relay-based (MMR) network architecture imposes a demanding performance requirement on relay stations. These relays will functionally serve as an aggregating point on behalf of the BS for traffic collection from and distribution to the multiple MSs associated with them, and thus naturally incorporate a notion of "traffic aggregation". However, the packet construction mechanism in IEEE 802.16/16e standard, which was designed for handling traffic solely on a per-connection basis, cannot apply on the relay link directly, as it may render a potential bottleneck and preponderantly limit the overall network capacity. As a solution, we propose two new efficiency-improvement schemes at the MAC layer, namely MPDU concatenation and MSDU aggregation, both of which incarnate the inherent notion of "aggregation" and alleviate the dismal efficiency degradation on the relay links. As confirmed by the performance evaluation, the proposed concatenation and aggregation schemes can achieve significant overhead reduction, and thus better prepare the 802.16e protocol for its adoption in MMR network