Design and Analysis of New Cooperative Buffer-Aided Relaying Schemes

Cooperative wireless communication has been proposed as one of the smart solutions to extend overall cellular coverage area and support better quality of service (QoS) for terminals specially those located on cell edges. Along with cognitive radio techniques (CR) and multiple-input multiple-output (MIMO) schemes, cooperative relaying is also representing an excellent area of research for the next generation wireless communication techniques 5G to improve both power and spectrum efficiencies and enhance the reliability of wireless communication. Recently, the concept of buffering was exported from the media access control (MAC) to the physical layer to enhance the way relay works. In this work, we propose to first investigate the single antenna scenario of buffer-aided relay network that uses different relay selection schemes. We will use convex optimization theory to derive an optimal expressions for the transmission power of user terminals and relay nodes that maximize the end-to-end normalized rate. In the same time, we will propose a low complexity bidirectional relaying protocol for buffer-aided relay network and then extend the bidirectional relaying protocol to the case of multiple relay scenario. For MIMO cooperative buffered relay networks, we will propose to design a low complexity relay selection and a bidirectional relaying protocol. The designed scheme will be followed by investigating an optimization methods that finds the best antenna transmission power values to maximize the end-to-end normalized rate. For the case of relay antenna transmission power, the targeted optimization rate function will be highly non-linear, so we propose to use some iterative and/or heuristic algorithms that assign the optimal relay antenna transmission power which yield maximum or near maximum end-to-end normalized rate. The proposed work will be a basement for future research on outage probability and bit error probability expressions derivation for both buffer-aided unidirectional and bidirectional relay networks. Our work must ends up with final conclusion about the efficiency and effectiveness of using physical layer buffering on cooperative relaying.