Adaptive Relay Selection Scheme for Minimization of the Transmission Time

As the installation of small cells increases, the use of relay also increases. The relay operates as a base station as well as just an amplifier. As the roles and types of relays become more diverse, appropriate relay selection technology is an effective way to improve communication performance. Many researches for relay selection have been studied to secure the reliability of relay communication. In this paper, the relay selection scheme is proposed for a cooperative system using decode-and-forward (DF) relaying scheme in the mobile communication system. To maintain the transmission rate, the proposed scheme classifies a candidate group considering the outage probability of multiple relays. For the applicable candidate group, the proposed scheme selects the relay considering the amount of data allocated to each user. Therefore, the proposed scheme defines the unit transmission time through each user's data and relay capacity. Finally, the proposed scheme selects a relay that minimizes the total transmission time through the relay transmission time that calculates the unit transmission time for all users. With this adaptive relay selection scheme, an optimal relay can be assigned for each user. For the same transmission rate and the amount of data, the proposed scheme improves the performance of transmission time and reliability. Simulation results show that the proposed scheme reduces the total transmission time for the same amount of data and signal to noise ratio (SNR).