Reliable And Efficient Data Transmission Strategy In Wireless Body Area Networks

Wireless Body Area Network (WBAN) is a human-centered Wireless Sensor Network with low power consumption. WBAN enables various applications in the field of e-Health, entertainment, sport training and so on. In human’s daily activities, since wireless body area channels are often blocked by human body, which leads to a strong shadowing effect of wireless body area channels, it is rather difficult to ensure the reliability of data transmission in WBANs. Besides, due to the very limited battery size of sensor nodes placed on human body, high energy efficiency of data transmission is essential to WBANs. In order to ensure the reliability and efficiency of data transmission in WBANs, we carefully design the data transmission strategies for WBANs according to the characteristics of WBANs:(1) Both the time-varying and the spatial characteristics of wireless body area channels are studied in the paper, and the channel models, i.e., time-varying model and spatial model, are presented correspondingly. By further derivation, two channel prediction models are obtained respectively based on the above channel models, thus realizing channel prediction in both temporal and spatial dimensions. Meanwhile, rationality and accuracy of the proposed channel models are verified based on measured channel data, and the parameters of channel models are obtained based, on the channel data measured in different scenarios, which can be taken as reference in subsequent research.(2) A prediction-based dynamic relay transmission strategy is proposed for WBANs. The proposed strategy makes full use of the time-varying and the spatial characteristics of wireless body area channels, and achieves proper and efficient utilization of relay nodes through channel prediction. Moreover, neither extra signaling procedure nor dedicated channel sensing period is introduced, so both the system complexity and the extra overhead are further reduced. Simulation results show that the proposed strategy achieves significant performance improvement in energy efficiency, as well as ensuring the transmission reliability.(3) A combined data transmission strategy is designed for WBANs by combining the cooperative relay transmission strategy with the non-cooperative dynamic slot assignment strategy. The combined strategy fully exploits the advantages of the above two strategies, and it enables dynamic allocation of transmission slots and relay nodes in an efficient way. Simulation results show that the proposed combined data transmission strategy, compared with pure relay transmission strategy, further improves the reliability and energy efficiency of data transmission in WBANs.