Cognitive radio networks (CRNs) have emerged as a promising, yet challenging, solution to enhance spectrum utilization, thanks to the technology of software defined radios. A well-known property of CRNs is the potential heterogeneity in channel availability among secondary users. Multicast throughput in CRNs may suffer from significant degradation because of this property, as it may force a source to transmit the multicast data over multiple channels to guarantee delivery to all neighboring receivers. In this presentation, we propose an assistance strategy to reduce the effect of the channel heterogeneity property on the multicast throughput in cognitive radio wireless mesh networks (CR-WMNs). This assistance strategy is composed of two main activities, first, allowing multicast receivers to assist the source in delivering the data, and second, allowing the transmission of network coded packets so that multicast receivers belonging to different multicast groups can decode and extract their data concurrently. We present optimal, and heuristic packet transmission scheduling strategies which implement the proposed assistance strategies. Performance results show that the proposed assistance paradigm achieves a considerable reduction in the total multicast time, which in turn increases the system throughput.
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