Design and Implement of a Relayed Assisted Emergency Wireless Communication System

In this paper, we design and implement a relay assisted wireless communication system for emergency communication purpose, which consists of one base station (BS), one relay station (RS), and multiple nodes. The nodes can communicate with the BS directly or with the help of the RS depending on the channel quality. A hybrid TDMA and slotted ALOHA protocol is proposed for the direct transmission nodes and relayed transmission nodes to exchange information with the BS. The proposed system is implemented based on STM32 microchip unit and a VHF wireless module, which enables voice and data communication. Field test results show that with the help of the relay, the maximum communication distance can be up to 3.1 km, and a significant gain in terms of packet error rate performance is observed for the relayed transmission as compared with the direct transmission.