High Throughput Low Delay Wireless Multicast via Multi-Channel Moving Window Codes

A fundamental challenge in wireless multicast hasbeen how to simultaneously achieve high-throughput and low-delay for reliably serving a large number of users. In this paper,we show how to harness substantial throughput and delay gainsby exploiting multi-channel resources. We develop a new schemecalled Multi-Channel Moving Window Codes (MC-MWC) formulti-channel multi-session wireless multicast. The salient fea-tures of MC-MWC are three-fold. (i) High throughput: we showthat MC-MWC achieves order-optimal throughput in the many-user many-channel asymptotic regime. Moreover, the numberof channels required by a conventional channel-allocation basedscheme is shown to be doubly-exponentially larger than thatrequired by MC-MWC. (ii) Low delay: using large deviationstheory, we show that the delay of MC-MWC decreases linearlywith the number of channels, while the delay reduction ofconventional schemes is no more than a finite constant. (iii) Lowfeedback overhead: the feedback overhead of MC-MWC is aconstant that is independent of both the number of receivers ineach session and the number of sessions in the network. Finally,our trace-driven simulation and numerical results validate theanalytical results and show that the implementation complexityof MC-MWC is low.