Optimization of delay-constrained video transmission for ad hoc surveillance

Recent increases in demand by militaries and disaster relief operations has greatly accelerated research on delayconstrained video surveillance with low-delay and high-quality video transmission. The following factors should be systematically analyzed due to the tradeoff between low delay and high quality: the visual importance of surveillance objects, quality degradation due to wireless channel dynamics, and variant end-to-end delay. We propose and optimize a low-delay video transmission technique for video surveillance over an ad hoc network. The proposed protocol is composed of intercommunication and intraprocessing parts. Through intercommunication optimization, we identify an optimal routing path and an associated relaying in terms of channel throughput that meet the source-rate, the flow-rate, and delay constraints. Through intraprocessing optimization, we identify an optimal packet length and an associated number of packets to adapt to the delay in the variant dynamic channel. Through simulations, we demonstrate that delay and throughput control significantly contribute to improvements in visual quality of up to 1.7-3 dB compared with conventional schemes.