A Static-Hybrid Approach for Providing Low Delay Routing

Multichannel, multihop wireless networks can improve system performance by allowing more simultaneous transmissions in the network than when compared to a single channel network. This in turn results in a higher network throughput and improved spectral efficiency. In order to maintain connectivity across nodes that operate on different channels, most of the existing multichannel implementations propose to switch the channels on the wireless radios. However, due to both software and hardware restrictions switching channels incur a significant delay, which can be prohibitive for many delay sensitive, real time applications, such as VoIP and interactive gaming. The situation can be worse in the case of a multihop network, as every node along the traffic path may require a channel switching delay that can add to the overall end-to-end delay. This motivates the need for efficient routing strategies that can make use of the flexibilities of a multichannel network while favoring delay sensitive applications by routing them on low delay paths. In this paper, we propose SHORT, a Static-Hybrid approach for rOuting Real Time applications over multichannel, multihop wireless networks, which ensures low delay paths for delay sensitive applications. Using measurements on a real multichannel testbed, we show that our protocol can provide significantly low delay multihop paths for delay sensitive applications (eg., VoIP) without degrading the throughput performance of non-delay sensitive, best effort traffic, such as TCP that may co-exist in a network.