Power Control Based Co-channel Interference Mitigation In Wireless Body Area Network

The aging process of human encouraging people to put more attentions on the e-health field (E-health), wireless body area network (Wireless Body Area Network, W-BAN), which is committed to the universal health care, surveillance, emergency alarms, etc, is designed to transmit the vital physiological signals. Wireless body area network occupies the the common ISM band to work, in which apart from the Bluetooth, Zig-bee, WiFi and some other wireless devices to share the same band. In some places like hospital, community and other environment where WBANs are largely deployed, there may exists huge coexistence of WBANs sharing the same limited spectrum resources to compete with each other devices. Some traditional resource allocation policies includ-ing time division and frequency division schemes are not suitable for the WBAN dense-ly distributed environments. Once these coexistence strategies fail, there will appear a plurality of wireless body area network occupying the same channel simultaneously to work, causing co-channel interference and making the data transmitted in the WBAN facing a serious risk of error even loss, which is intolerable due to the importance of WBAN to monitor and transmit the vital health data. Therefore, it is significant for uni-versal health care practitioner to design the interference mitigation strategy to overcome the inter-WBAN coexisted interference problems.In this paper, we focus on the scenario that WBANs are intensively distributed by introducing power control scheme to solve the problem of co-channel interference. Because of the independence of WBANs, adapting own power may cause more serious interference to others, which motivates us to introduce the game theory to conquer the problem. Each WBAN is assumed to be a player of the power control game, and by the means of adjusting the strategy (e.g. transmission power), so that all coexisted WBANs can reach a steady state of Nash equilibrium. On the basis of analysis the multiple links structure and heterogeneity of WBAN, we propose the Quality of Service (QoS) driven power control game model to suppress the inter-WBAN interference for the static scenes; Moreover, taking mobility of real scene into consideration, we further propose the inter-WBAN interference mitigation strategy to solve the interference problem in mobile scene, which will be introduced as bellow separately:·Focusing on the scene that the relative position of WBANs don’t change and a more realistic multiple-link inside the WBAN, we propose a QoS driven pow-er control game to mitigate the inter-WBAN interference problem based on the consideration of heterogeneous QoS requirements and the limited energy con-sumption. Then the existence of at least one Nash Equilibrium of the proposed game is proved and further derive the sufficient condition to guarantee the unique NE. In order to overcome the problem lacking of key information for updating the transmission power due to the independence of multi WBANs, we further present an non-cooperative approximation algorithm to reach the Nash equilibrium. The simulation results of experiment show the correctness and effectiveness of the proposed estimated algorithm to reach Nash equilibrium.·On this basis of above, we further take the impact of inherent social mobility of WBAN into consideration, and construct the power control game model for the mobile scene. Although the signal gain of link and topology structure of inter-network is dynamicly changed for the reason of mobility property of WBAN, but the mobile game proposed by this paper can still exists at least one Nash equilibrium and the uniqueness of Nash equilibrium is also guaranteed. Finally, the effectiveness of the MISE algorithm to get the unique Nash equilibrium is proved in the later simulations.