A Cooperative ARQ Strategy with Adaptive Back-Off for Mobile Multimedia Communication Using Cognitive Relays

Cooperative ARQ schemes are effective to enhance the quality of communication for the next generation mobile communication systems. In this paper, we propose a cooperative ARQ strategy for supporting instantaneous cooperation in MANET environment using ad hoc cognitive relays. In the proposed strategy, whenever a data frame is transmitted from the source, nearby relays actively sense the SINR of the signal, and proactively propose a cooperative retransmission, if necessary, before the receiver replies with NACK feedback. By computer simulation, it is shown that the proposed cooperative ARQ scheme outperforms the conventional schemes with respect to frame transmission delay and the frame loss probability.