Towards Guaranteed QoS in Mesh Networks: EmulatingWiMAX Mesh over WiFi Hardware

Currently deployed wireless mesh networks are based on 802.11, WiFi, technology, which is not efficient in multihop scenarios. We present a method for embedding 802.16 packets into 802.11 broadcast packets and padding the 802.11 broadcast payload, so that the broadcasts are aligned to 802.16 TDMA frame boundaries. Our method requires only software changes on the nodes using 802.11a for mesh communications. This means that the mesh networks installed with 802.11a hardware today can be upgraded with a software patch to take advantage of 802.16 MCF and do not have to wait for hardware upgrades to 802.11s. We show that despite the addition of the padding, emulated 802.16 has bandwidths comparable to the bandwidth achievable with 802.16 hardware. The efficiency of the hybrid system is significantly higher than the efficiency of 802.11 based systems. The new system can also provide deterministic guarantees on link bandwidths since it takes advantage of scheduled wireless access with 802.16 MCF. We use ns2 simulations to show the improved efficiency and guaranteed link bandwidth of the 802.11 based hardware using the emulated 802.16 MCF.