A cross-layer adaptation HCCA MAC for QoS-aware H.264 video communications over Wireless Mesh Networks
We present in this paper a novel scheme of QoS-guaranteed transmission of H.264 video over Wireless Mesh Networks (WMNs) based on a Cross-Layer Adaptation HCCA (CLA-HCCA) MAC protocol. This CLA-HCCA strategy utilizes the queue length information at the MAC layer and the MAC layer interference estimation for optimal routing selection at network layer. The scheme will exchange timely Link Capacity Estimation (LCE) information for an adaptive adjustment of spectrally capable transmission at the physical layer. This Cross-Layer Adaptation approach provides an optimized transmission to guarantee the minimum packets delay and drop rate needed for time bound applications, such as video. Since conventional IEEE 802.11e HCCA MAC does not offer cross-layer design framework, we need to resolve the problem associated with IEEE 802.11e HCCA MAC by designing a novel adaptive architecture based on LCE. This integrated scheme allows the physical layer to achieve the optimal transmission via Video-Adaptive FEC (VA-FEC) scheme implemented in the application layer. We evaluate the proposed scheme based on network-level metrics, including bit rate, packets delay and drop rate, in comparison with the state-of-the-art Physical Rate Based Admission Control scheme (PRBAC) HCCA MAC scheme based on IEEE 802.lie WMNs. Extensive simulation results based on H.264 video transmission for the proposed CLA-HCCA and the PRBAC-HCCA schemes have been obtained. We have confirmed that the proposed CLA-HCCA strategy outperforms the PRBAC-HCCA MAC by a significant margin as LCE and VA-FEC is able to adapt to the dynamic network conditions of IEEE 802.lie WMNs in a timely fashion.