Feasible cooperative communication with IEEE 802.11a based devices for multi-hop networks

Abstract

Wireless multi-hop networks are candidate communication infrastructures in developing regions because their installation cost is quite low comparing to that for conventional wired networks. Reliable and scalable dissemination mechanism is required in practical multi-hop networks. Cooperative communication is a new scheme to improve communication performance to realize a reliable dissemination mechanism. However, high mobility networks have a big issue for autonomous control for cooperative communication. Additionally, conventional cooperative schemes cannot reduce packet collisions even if packet collisions are a big degradation factor of performance in dense multi-hop networks. We have discussed a new cooperative communication scheme that employs Orthogonal Frequency-Division Multiplexing (OFDM). Our scheme can improve communication performance and reduce packet collisions based on distributed control matter. Our advance evaluation has shown a good potential of the proposed scheme to improve communication performance in multi-hop network simulations. On the contrary, the feasibility of the proposed scheme with a real hardware device was not shown. This paper evaluates the feasibility of our original cooperative communication scheme on IEEE 802.11a standard devices. Almost all conventional cooperative communication schemes require a special physical layer and a media access control mechanism. We have focused on a characteristic of OFDM, where a receiver can demodulate multiple signals within a guard interval period. The experimental evaluation has been performed with software defined radio devices (USRP B200). We have implemented multiple transmitters, a receiver and a fading simulator for each transmitter with two USRP B200 devices. The results can show that the proposed scheme works well on IEEE 802.11a standard devices and improves communication performance in practical situations. Hence, the proposed scheme will be a new candidate of cooperative communication mechanisms that can employ general consumer devices and can realize effective dissemination mechanism for multi-hop networks.