On Multicast Capacity and Delay in Cognitive Radio Mobile Ad Hoc Networks

In this paper, we focus on the capacity and delay tradeoff for multicast traffic pattern in cognitive radio mobile ad hoc networks (MANETs). In our system model, the primary network consisting of n primary nodes overlaps with the secondary network consisting of m secondary nodes in a unit square. Assume that all nodes move according to an independent and identically distributed mobility model, and each primary node serves as a source that multicasts its packets to kp primary destination nodes, whereas each secondary source node multicasts its packets to ks secondary destination nodes. Under the cell partitioned network model, we study the capacity and delay for the primary networks under two communication schemes, i.e., noncooperative scheme and cooperative scheme. The communication pattern considered for the secondary network is cooperative scheme. Given that m = n^β (β > 1), we show that per-node capacities O(1/k_p) and O(1/k_s) are achievable for the primary network and the secondary network, with average delays Θ(n log k_p) and Θ(m log k_s), respectively. Moreover, to reduce the average delay in the secondary network, we employ a redundancy scheme and prove that a per-node capacity O(1/k_s √m log k_s) is achievable with average delay Θ(√m log k_s). We find that the fundamental delay-capacity tradeoff in the secondary network is delay/capacity ≥ O(mk_s log k_s) under both cooperative and redundancy schemes.