A protocol of multi-phase cooperative wireless networks for the lowest outage probability

Multi-phase cooperative communication in a wireless network is studied in this paper. Each node is a mobile module having multiple antennas (MA) or a group of sensors forming a virtual antenna array (VAA). The scenario comprises a number of multiple-input multiple-output (MIMO) channels with mutually independent Rayleigh fading processes. A data frame from a signal source node is split into portions. Each portion is transmitted from a distinct node in a sequential manner to the destination node. Theorem 1 gives the criterion on how to select wireless nodes for achieving the lowest outage probability of information capacity. Theorems 2 and 3 give the closed-form expressions of the optimal frame splitting (FS) ratios for arbitrary signal-to-noise (SNR) situations. In situations, where a large number of nodes satisfy the condition in Theorem 1, a protocol is proposed to select a limited number of nodes to achieve a satisfactory performance. The theoretical results are useful to designing practical cooperative communication systems.