Linear-mapping based cooperative relaying protocol design with optimum power and time allocation

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, we intend to design and optimize cooperative communication protocols by exploring all possible variations in time and power domains. In our recent work [18], we explored an ideal non-equal-time cooperative relaying protocol where the system can use arbitrary re-encoding methods at the relay and adjust time allocation arbitrarily, in which we showed that with optimum power and time allocation the cooperative relaying protocol has significant performance improvement compared to the equal-time relaying protocol. In this paper, with more realistic consideration, we design a practical cooperative relaying protocol based on linear mapping, i.e. using linear mapping as the re-encoding method at the relay and considering integer time slots in the two phases. Furthermore, we develop an optimum linear mapping to minimize the outage probability of the linear-mapping based cooperative relaying protocol. Numerical and simulation results show that the performance of the proposed cooperative relaying protocol based on the optimum linear mapping is close to the performance benchmark of the ideal cooperative protocol.