A Cross-Layer Judgment Scheme for Solving Retransmission Problem in IEEE 802.15.4-Based Wireless Body Sensor Networks

In IEEE 802.15.4 wireless personal area networks (WPANs), reliable data transmission is an important issue in areas such as body information for medical treatments. Some handshaking mechanisms in literatures are studied and proposed to guarantee successful data frame transmission. One is to adopt ACK frame, which is replied by the receiver back to the sender when the data frame is correctly received. This is a popular mechanism. However, there are many different reasons, such as the fading channel, data frame collision, and hidden terminal problem, by which data frames cannot be correctly received on the receiver. Therefore, a sender should have different data retransmission policies and procedures for data frame retransmission. Neglecting these measures of failed transmission, the data frame retransmission may fail again, and the transmission efficiency will be degraded. In this paper, we propose a cross-layer judgment scheme (CL-JS) to solve the retransmission problem. It does not require the extra control overhead, but it can correctly judge the reasons of failed transmission from overlapped signals. Thus, the sender can adaptively adjust system parameters to handle the different retransmission procedures. Simulation results validated by mathematical analysis show that the proposed scheme significantly improves the goodput with the reduction in power consumption.