Reliability and Delay Trade-Off Analysis of Unslotted IEEE 802.15.4 Sensor Network for Shipboard Environment

Wireless sensor network technology has been widely studied and applied in different fields. The applications in shipborne wireless sensor networks face serious physical-layer packet loss problems due to the wireless signals blocking by steel structure and wireless channel interference. The MAC-layer retransmission mechanism can reduce the packet loss rate but increases latency. So it's necessary to analyze the performance of reliability and latency for different applications in shipborne wireless sensor networks. In this article, first, we analyze the distribution of the physical-layer packet loss rate for IEEE 802.15.4 sensor network in ship indoor environment. We also present an analysis model based on three-dimensional Markov chain for unslotted CSMA/CA of IEEE 802.15.4 sensor network considering physical-layer packet loss rate and MAC-layer retransmission. We evaluate the effects of three MAC parameters, macMinBE, macMaxCSMABackoffs, and macMaxFrameRetries, on average delay and reliability. The percentage error of the analytical model for delay and reliability are 2.09% and 1.37%, respectively. Our work provides trade-off analysis between average delay and average reliability using the maximum number of retransmission based on the measured data of physical-layer packet loss rate in shipboard environment for different QoS requirements.