Research On The Coexistence Of Multi-protocol Wireless Heterogeneous Intelligent Internet Of Things

The resources of 2.4 GHz ISM(Industrial Scientific Medical)band are very limited,mainly because different wireless communication protocols such as Wi-Fi,Bluetooth.ZigBee and Thread share bandwidth in this band[1].Most of the smart devices emerging in recent years have formed the Internet of Things through wireless connection technology,has exacerbated the congestion in the 2.4G band resources.To improve interference robustness,each wireless protocol standard in the 2.4G band supports some kinds of conflict avoidance mechanism or message retransmission function.However,when these wireless communication protocols work simultaneously in the same location,it is still inevitable that channel overlap will occur even in the same channel,making the signal from one wireless protocol generate noise interference to another wireless protocol,and the higher noise power can even drown out the effective signal,resulting in incorrect message reception.This paper adopts the PTA(Packet Traffic Arbitration)recommendation based on the IEEE 802.15.2 standard to conduct relevant research on the coexistence problem of 2.4G wireless communication protocols,combining the three wireless communication technologies of BLE(Bluetooth Low Energy),ZigBee and Wi-Fi,which have the most abundant application scenarios,to mitigate the communication interference problem under the same frequency band through coordinated management.The main work of this paper is as follows:1)Briefly listed the more mature anti-interference mechanisms in current 2.4G wireless protocols,including unmanaged coexistence schemes,and managed coexistence schemes in existing studies.2)Implemented the custom data sending and receiving in the application protocol layer according to the data frame format specified by each protocol,as well as the statistics of the key characterization parameters of coexistence performance,packet loss rate and throughput.3)This paper proposes an optimization method for standard PTA.When the coexistence end of BLE device is BLE Slave,the REQ is asserted for the synchronous RX window of its connection events to improve the coexistence performance,and the coexistence function and callback processing of BLE Slave and ZC(ZigBee Coordinator)with Wi-Fi AP(Access Point)through 1-wire REQ PTA mode are realized.4)This paper proposes a method to assert REQ in advance for BLE Slave,which can further optimize the coexistence performance of the system for Wi-Fi devices that have integrated PTA but do not support preemption.5)Finally,a test network is built to compare the coexistence performance of wireless protocols in the system before and after optimization to verify the beneficial effects of the scheme in this paper.The experimental results show that:1)Due to the low-power design of BLE and ZigBee,the TX power of Wi-Fi is much higher than that of BLE and ZigBee,so Wi-Fi devices are the primary source of interference in the coexistence system,while the mutual interference between BLE and ZigBee is small or even negligible.2)Compared with just using unmanaged coexistence schemes,by using the standard PTA recommendation,the packet loss rate and throughput of BLE and ZigBee are significantly improved at the expense of less Wi-Fi performance,and the overall coexistence performance of the system is enhanced.3)Compared with standard PTA:when BLE and Wi-Fi coexist,the packet loss rate of BLE is further reduced by more than 50%,the throughput is increased by more than 4%,and the throughput of Wi-Fi is only reduced by 0.28%.When BLE,ZigBee and Wi-Fi coexist,the packet loss rate of BLE is reduced by more than 60%,the throughput is increased by 7%,and the throughput of Wi-Fi is reduced by 1.4%.The optimization scheme in this paper can improve the coexistence performance of BLE on the basis of sacrificing a small part of Wi-Fi performance,which reflects the beneficial effect of this paper on the optimization of standard PTA recommendations.