Abstract:

Cooperative communication technology can efficiently achieve spatial diversity and improve the system performance. In order to minimize the total power consumption and satisfy the data rate requirement of a decode-and-forward (DF) multi-relay cooperative system, an optimized Lagrange algorithm based relay selection and power allocation scheme was proposed. Based on the utilization of the instantaneous channel state information (CSI) between the source and the relays, the minimal transmit power of the source and the largest decoding relay set could be obtained. With the application of the Lagrange multiplier technique, the power allocation for the source and the relays could be obtained, and the best relays could be selected from the decoding relay set to minimize the total system power consumption. Simulation results showed that the total power consumption of the proposed scheme was significantly reduced compared with that of the direct transmission and the opportunistic relay selection (ORS) scheme.

Key words: cooperative communication, decode-and-forward (DF), power allocation, relay selection, opportunistic relaying;Lagrangian algorithm