Optimum power and time allocation for cooperative relaying protocol

Cooperative communication has emerged as a new wireless network communication concept, in which parameter optimization such as power budget and time allocation plays an important role in cooperative relaying protocol designs. While most existing works on cooperative relaying protocol designs considered equal-time allocation scenario, i.e. equal time duration is assigned to each source and each relay, in this work we intend to design and optimize cooperative communication protocols by exploring all possible variations in time and power domains. We jointly optimize the power and time allocations for the cooperative relaying protocol such that the outage probability of the protocol is minimized. Specifically, for any given time allocation, we are able to determine the corresponding optimum power allocation analytically with a closed-form expression. We also show that in order to minimize the outage probability of the protocol, one should always allocate more energy and time to the source than the relay. Extensive numerical and simulation studies illustrate our theoretical developments.