Research On Channel Access Schemes For Wireless Personal Area Network

With the rapid development of wireless communication technology, people’s demand of applications using wireless communication technology constantly grows, and instead of being satisfied to basic communication needs, people are urging the short-range dedicated network services to realize short distance wireless communication. The appearance of WPAN (Wireless Personal Area Network) exactly meet people’s such demands.In order to promote the development of wireless personal area network technology, IEEE standardization organization sets up IEEE802.15working group, among which IEEE802.15.4protocol with its low-rate, low power and low cost advantages is highly approved by many communication companies and research institutions.In this paper, based on the theoretical basis of IEEE802.15.4protocol and its analysis in depth, research on channel access mechanisms were studied, including three areas:channel scanning and channel selection mechanism before channel access, channel access competition mechanism during channel access, and re-entry channel access process after the loss of channel connection. Corresponding technical Defects of the three mechanisms in specific application scenarios were analyzed in depth, and three corresponding technical solutions were proposed:Firstly, aiming at the wireless personal area network application scenario’s complex channel characteristic, this paper uses dynamic channel scanning and selection mechanism to dynamically scan available channels in application scenarios so that channel used with an non-ideal quality could be efficiently switched to a high-quality communication channel to improve the wireless personal area network. Communication equipment’s adaptability to changeable channel environment can guarantee the network to constantly work at a high-quality communication channel. Simulation results prove the mechanism’s effectiveness in packet loss rate and network interruption times; Secondly, taking into account IEEE802.15.4protocol’s lack of QoS differentiated channel access services for data of multi-service type, priority-based Adaptive Timeslot allocation scheme was proposed. During the channel competition access phase, the number of nodes which is used to adaptively allocate times lots’number and sequences to distinguish channel access of high priority from that of low priority and provide QoS priority differentiated services. The simulation results show that the mechanism could differentiate services with various QoS priorities, and performs well in the channel access probability, adaptability, back-off number, time delay and throughput times. Finally, aiming at the inefficiency of IEEE802.15.4protocol on channel re-access while device loses synchronization, a fast re-association mechanism was proposed by reserving re-association phase and using means like signaling interaction during re-association phase to achieve efficient and safe re-association process. Research of this study is of reference value to the future application and research of wireless personal area network technology.