Efficient techniques for enhancing coexistence of wireless technologies in WBAN

Abstract

Wireless Body Area Network (WBAN) is a time critical remote network where various physiological information of patients are sent through this sensitive network satisfying stringent quality of service (QoS) requirements. The performance of WBAN may degrade severely due to the coexistence problem which is a well known incident where the overlapped frequency bands are shared by di erent wireless channel access technologies. However, the coexistence problem of WBAN is classi ed into two types which are addressed as mutual and cross interference. A WBAN may dynamically coexist with other WBANs, and thus they may su er from signi cant performance deterioration because of interference among themselves which is known as mutual interference. Apart from the lack of available spectrum, the technologies used by the WBAN as well as other devices may operate in the same 2.4 GHz unlicensed industrial, scienti c, and medical (ISM) bands which is de ned as cross interference. In order to guarantee reliable communication for sensor nodes of WBAN, it requires the prediction of coexistence condition. Existing research works de ne three different coexistence mitigation schemes (beacon shifting, channel hopping, and active superframe interleaving) to handle coexistence conditions. However, there is no speci c detailed algorithm for these coexistence mitigation and handling schemes. In order to overcome the shortcomings of coexistence mitigation schemes in the WBAN and to satisfy requirements of WBANs, this thesis proposes two di erent coexistence mitigation schemes. The rst scheme is to mitigate mutual interference using fuzzy logic based algorithm where the state of the sensor nodes is detected. Packet Error Rate (PER), Signal to Interference Noise Ratio (SINR) and Received Signal Strength Indicator (RSSI) are the key parameters as membership function of this algorithm for detecting the state of nodes. Moreover, the second scheme focuses on channel agility technique to mitigate the cross interference, where nonoverlapping free channel is predicted based on Naive Bayes Classi er algorithm. PER, RSSI, SINR and previous state of the channel are the attributes of this classi- er in order to predict the state of the channel. A simulation model using Castalia and Matlab is designed to show the e ectiveness of the proposed schemes. Simulation results show that our proposed techniques e ectively mitigate the coexistence problem in WBAN scenarios.