Research Of Body Area Network MAC Algorithm Under Interference Environment

With development of communication technology, wireless interconnections existeverywhere in our daily life. Wireless Body Area Network (WBAN) is thecommunication network close related to users, which becomes a hot spot in recentresearch.Currently applications of WBAN are major in medical and health-care fields. Thespecial application fields raise high requirements on system performance. Challengesboth inside and outside WBAN system will be faced during the designing process.Internal challenges include the limitation of node power consumption and QoSrequirement of traffic transmission. External challenge comes from environmentinterference in the process of wireless transmission. Designing a MAC algorithmsuitable for WBAN system is an effective way to resolve these challenges. Research ofWBAN MAC algorithm under interference environment is carried out in this article.Firstly we have a deep research on WBAN related MAC algorithms and solutionsto environment interference. MAC algorithms are divided into contention based andscheduled based according to channel resource allocation mechanism. Solutions toenvironment interference are divided into cooperative optimization and standaloneoptimization according to working mechanism. Comparisons are made betweendifferent methods with consideration of WBAN situation.Then a hybrid MAC algorithm is proposed which is designed to meet theperformance requirements of WBAN application. The proposed algorithm combinesthe advantages of high energy-efficiency in scheduled based transmission and fastresponse of burst traffic in contention based transmission. Our algorithm reserves timeslots for regular traffic to enable data communication with high energy efficiency andallows the time slots be snatched by emergency traffic to guarantee fast response ofburst traffic. Requirements of low power consumption and fast response of burst trafficare satisfied. Effectiveness of algorithm is validated with theoretical analysis and software simulation.Next, environment interference is considered and a solution based on powercontrol is proposed to mitigate negative impact of interference on network performance.The solution firstly makes an estimation of channel usage. The channel is modeled atwo-state model which is either busy or idle and hyper-exponential model is used todescribed the distribution. Parameters are calculated with existing measured data byEM algorithm and future channel states are estimated according to calculation ofresidual idle time. When sending data packages, nodes will select transmit poweraccording to estimation of channel status. If the channel is expected to be idle, nodestransmit with lower power. Otherwise higher power will be used to ensure adequateSINR in the receiver end which meet the minimum requirements of demodulation, soas to guarantee the quality of data communication.Last we design and develop a hybrid validation system which combines hardwarecircuits and computer software. The validation system provides both basic function ofcommunication validation and good interoperability by providing an easy-to-use humaninterface. We also validate effectiveness of our proposed MAC algorithm on our hybridvalidation system.