Cross-layer design for delay-constrained error-resilient video communications over wireless ad-hoc networks

For video communications over wireless ad-hoc networks, there are fundamentally two different kinds of packet losses: packet losses due to channel over-pumping, where the operating transmission rate is higher than the prevailing channel capacity, and packet losses due to transmission errors. To eliminate the first kind of packet losses, rate-control is necessary in order to adapt to the time-varying channel capacity. For the second kind of packet losses, error-resilient coding techniques should be used. In this paper, we propose a cross-layer rate-control scheme based on an analytical study of how the effective video transmission rate is affected by the prevailing operating parameters. Furthermore, in order to provide error-resilient real-time video delivery over such wireless ad-hoc networks, a cross-layer delay-constrained joint source-channel coding (JSCC) approach, to be used in conjunction with rate-control, is proposed and investigated. Simulation results demonstrate the effectiveness of this combination of cross-layer rate-control and delay-constrained JSCC for supporting error-resilient video delivery over wireless ad-hoc networks operating under a delay constraint.