An OCDM-Based Channel-Controlled G-STAR Protocol for 3-D Wireless Networks

With the widespread application of wireless sensor networks (WSNs), geometric routing has been frequently investigated for its low complexity and high delivery rate. However, most existing geometric routing schemes seldom pay attention to the channel quality of the found route. As multimedia applications are being extensively used in networks, the transmission with higher robustness has become a growing demand. In this article, we propose a channel-controlled geometric STAteless routing (CC-G-STAR) scheme for 3-D wireless networks. The proposed routing scheme inherits the light-weighted merits of the G-STAR protocol and guarantees packet delivery as long as a route exists. Furthermore, multicarrier (MC) transmission such as orthogonal chirp division multiplexing (OCDM) modulation is employed to achieve high data rate and robust communication. The orthogonality deficiency (od) of the channel state information (CSI) is introduced, instructing the routing scheme to find a route with favorable channel conditions. This channel-controlled metric enables low-complexity linear equalizers (LEs) to collect lost diversity at the receiver node. The effectiveness of the proposed scheme was evaluated by simulations. The results show that the CC-G-STAR scheme exhibits a 6-dB advantage in bit error rate (BER) performance while maintaining a 10%–15% higher delivery rate against the routing without channel-controlled factors. Image transmission simulations were conducted and the received images routed by the CC-G-STAR achieved a structural similarity (SSIM) of over 0.9.