Low Latency Broadcast in Multi-Radio Multi-Channel Multi-Rate Wireless Mesh Networks

Abstract—This paper addresses the problem of “efficient ” broadcast in a multiradio, multichannel, multirate wireless mesh network (MR2-MC WMN). In such anMR2-MC WMN, nodes are equipped with multiple radio interfaces, tuned to orthogonal channels, that can dynamically adjust their transmission rate by choosing a modulation scheme appropriate for the channel conditions. We choose “broadcast latency, ” defined as the maximum delay between a packet’s network-wide broadcast at the source and its eventual reception at all network nodes, as the “efficiency ” metric of broadcast performance. We study in this paper how the availability of multirate transmission capability and multiple radio interfaces tuned to orthogonal channels in MR2-MC WMN nodes can be exploited, in addition to the medium’s “wireless broadcast advantage ” (WBA), to improve the “broadcast latency ” performance. In this paper, we present four heuristic solutions to our considered problem. We present detailed simulation results for these algorithms for an idealized scheduler, as well as for a practical 802.11-based scheduler. We also study the effect of channel assignment on broadcast performance and show that channel assignment can affect the broadcast performance substantially. More importantly, we show that a channel assignment that performs well for unicast does not necessarily perform well for broadcast/multicast. Index Terms—Routing, broadcasting, wireless mesh networks, multiradio multichannel, multirate. Ç