Research On Coding Mechanism In Wireless Body Area Networks

Wireless body area network is defined as a body-centric system, and it has multiple features such as information collection, data processing and wireless transmission. Due to the rapid development of aging population and a serious shortage of medical resources, there are great application requirements in modern health care field such as remote health care and community health care. So people pay more and more attention to the person-centered wireless networks. The biggest difference between wireless body area network and other traditional networks is that it is a body-centric network. It needs to transmit human physiological information reliably and real-time. As the complexity of body surface feature, the body structure and environment, and the topology of wireless body area network changes dynamically with the body motion, the channel characteristics of wireless body area network is relatively complicated. The instability of channel environment brings a series of difficulties to the realization of reliable transmission. So regarding the special environment of human body, this paper focuses on how to improve the reliability of communication and guarantee the quality of service under the dynamic network topology condition of the wireless body area network.By analyzing the characteristics and requirements of wireless body area networks, we can use channel coding to improve the reliability of information transmission. At first, this paper analyzes the performance of fountain codes in wireless body area network by regarding the particularity of human body model and the complexity of the human motion. Fountain code is a kind of rateless code, the encoding efficiency does not need to be determined in advance. It has high adaptability to the environment and the energy efficiency and reliability are high. This paper analyzes and compares the reliability of several typical fountain codes such as LT codes, Raptor codes and Spinal codes. The Python simulation results show that the average coding efficiency of Spinal codes is higher than LT codes and Raptor codes, which indicates that Spinal codes can adapt to the time-varying channel conditions better. The average coding efficiency of Raptor codes is higher than LT codes, this is because Raptor codes use pre-coding which has the error correction capability and strong anti-inference ability.Then, in order to analyze the communication quality of fountain codes in a wireless body area network, this paper implements LT codes on Shimmer physiological sensors through modular programming. This paper also introduces the realization of wireless transceiver module, LT encoding and decoding modules, data storage module and data acquisition module. Finally, this paper does a large number of experiments in actual wireless body area network under different transmission distances, different external environments, different body motions and different degree distribution functions. We conduct statistical analysis and comparison on the experimental results. Though these studies, we can get the conclusion that fountain codes can effectively protect the quality of communication and the reliability of information transmission in wireless body area network.