Performance of a Relay System for Two Extreme Ends of a Vessel at 2.4 GHz

Abstract

Due to the complex metallic environment onboard a vessel, it is difficult to establish a communication link in the ISM frequency band of 2.4 GHz between the two extreme ends of the vessel, i.e., the bridge room and the engine control room (ECR). Therefore, in this letter, a relay system is proposed to overcome the difficulty. The cargo hull with its analogous waveguide structure is found to be a good location for relay. The cargo hull's structure demonstrates wave guiding effect that is able to enhance radio wave propagation. Wideband channel sounding has been conducted over two independent links of a relay system: from the bridge room to the cargo hull, and from the cargo hull to the ECR. Based on the measured impulse responses, channel performances such as average received power, root mean square (rms) delay spread, and ray decay factor are studied and compared for the two links. A maximum usable bandwidth of 0.5 MHz can be achieved without using any equalizer at 2.4 GHz. Although this bandwidth is small, it is sufficient for the transmission of low-data-rate images.Index Terms-24 GHz, multipath, relay, ship propagation, waveguide effect.