Effective Capacity of Superposition Coding Based Mobile Multicast in Wireless Networks

Effective capacity is a useful technique to characterize the system throughput with statistical delay-constrained quality of service (QoS) guarantees. In this paper, we integrate effective capacity theory into superposition-coding (SPC) based multicast transmission to devise the efficient channel-aware multicasting scheme in wireless networks. Specifically, we propose to optimize the effective capacity for multicast transmissions subject to the specified loss-rate constraint and the statistical delay QoS requirement in terms of the QoS exponent. We use superposition coding in wireless multicast to handle heterogeneous channel fading across multicast receivers, and apply the pre-drop strategy to gain more flexible rate control. Under our proposed framework, we derive the optimal pre-drop strategy and the optimal power/rate allocation for each layer of superposition coding. Simulation analyses present insightful observations on tradeoff between effective capacity and the QoS requirements, and demonstrate the superiority of the SPC-based scheme over the existing time-sharing (TS) based multicast scheme.