Smart network access for 802.11 based internet of things

摘要

Internet of things (IOT) not only push radio nodes to sense and hear wireless medium, it also does provide opportunity to learn and adapt to radio neighborhood. As number of IOT nodes cherish, spectrum scarcity and interference management becomes non-trivial. As 802.11 radios are vital frontrunners to realize IOT technology, 802.11 channel access algorithms at MAC layer in IOT nodes play a vital role to attain maximum achievable throughput by managing spectrum and interference. Contention based, binary exponential back off CSMA/CA is default channel access mechanism for most 802.11 IOT radios for sake of its simplicity and applicability in both ad-hoc and infrastructure modes. Even though contention free and polling based point coordinated function (PCF) is illustrated in IEEE 802.11 standards, it to be implemented along with distributed coordinated function (DCF), for adding new nodes to same channel. Time division multiple access (TDMA) based medium access layers(MAC) also implements RANDOM ACCESS PHASE to add new radios to channel. DCF, PCF and TDMA fall flat in managing interference in same channel. In this paper a novel interference and spectrum aware channel access mechanism for 802.11 infrastructure and adhoc network, is proposed based on perceived RSSI, RCPI and SNR metrics by generating signal-strength-snr graph to combat interference. Proposed method also uses concept of adaptive channelization to address effective spectrum management. Mentioned channel access algorithm allow multiple parallel wireless conversations possible in same channel.