Alternating Opportunistic Large Arrays in Broadcasting for Network Lifetime Extension

Abstract—We propose a protocol for broadcasting in wireless multihop networks that is based on a form of cooperative transmission called the Opportunistic Large Array (OLA). An SNR (“transmission”) threshold is used to define two mutually exclusive sets of OLAs, such that the union of the sets includes all the nodes in the network. The broadcast protocol then alternates between the sets for each broadcast and is called Alternating OLA with Transmission Threshold (A-OLA-T). Under A-OLA-T, all participating nodes transmit with the same low power, therefore the energies of the nodes in the network drain efficiently and uniformly, extending the network life relative to broadcasts that use simple OLA or non-alternating OLAs with a transmis-sion threshold. In this paper, we optimize the A-OLA-T protocol under the continuum assumption (very high node density). Index Terms—Broadcast, cooperative transmission, oppor-tunistic large arrays, wireless sensor networks. I