Multi-Packet Opportunistic Large Array Transmission on Strip-Shaped Cooperative Routes or Networks

Abstract

The Opportunistic Large Array (OLA) is one type of cooperative transmission, which provides fast and reliable broadcasts and unicasts in multi-hop networks. While the existing literature on OLAs assumes one-shot transmission with a single packet, we analyze multi-packet OLA transmission within a single flow along strip-shaped networks or OLA-based cooperative routes. When multiple packets are transmitted from the same source using the same channel before the previous packet has cleared the network, which is called spatial pipelining, intra-flow interference is produced by OLAs transmitting co-channel packets. Using the continuum assumption (approximated by high density networks), the authors optimize the throughput. This paper theoretically shows spatial pipelining over strip networks is always feasible for path loss exponent α≥2, which is not true for disk-shaped networks. Moreover, the impacts of system parameters are analyzed, and the upper bound of the optimal packet spacing (the lower bound of the optimal throughput) is derived. Also, spatial pipelining in finite networks is studied with numerical results, which confirm the theoretical analysis.