Coexist WiFi for ZigBee Networks With Fine-Grained Frequency Approach

Ping Li,Yubo Yan,Panlong Yang,Xiang-Yang Li,Qiongzheng Lin

doi:10.1109/access.2019.2941963

Abstract

The widely deployed WiFi APs and ZigBee devices make the coexistence for these two networks more pervasive than ever. Previous solutions focus on the contention resolution in time domain, but would lead to the underutilized frequency resources. However, for frequency domain schemes, to enable efficient coexistence for WiFi and ZigBee networks, the WiFi nodes or ZigBee nodes have to select the appropriate channel for transmission. Such scheme will need strict cooperations among these two independent systems, and could not work with the conventional legacy systems seamlessly. In this paper, we propose a frequency overlay approach named COFFEE (COexist wiFi For zigbEE networks), where subcarriers interfering with ZigBee transmissions are nullified by WiFi. According to our basic evaluations, due to the relatively robust feature in WiFi/OFDM design, nullifying small portion of subcarriers would affect the WiFi performance slightly, but could improve the capability for coexistence significantly. Thus by using COFFEE, WiFi and ZigBee nodes can transmit their packets concurrently without any coordination. Also, COFFEE and conventional legacy WiFi systems could work together seamlessly. Furthermore, we implement COFFEE with USRP software radio platform and evaluate the performance under real wireless network scenarios. The extensive evaluations show that compared to the coexistence schemes in time domain, COFFEE is able to increase the network throughput by more than 300%. Even when the ZigBee node never knows the transmission time of WiFi packet, it still can provide concurrent lossless transmission by using COFFEE with only 10% to 15% WiFi throughput reduction.

Highlights

The demand for information has brought prosperity to network systems such as WiFi and zigbee, which have crowed the 2.4GHz ISM band where these networks operate at
2) We focus on the issues of WiFi and ZigBee networks coexistence and propose certain customized techniques to improve the efficiency of both networks
In order to make a deep sense of how COFFEE performs on the coexistence of WiFi and ZigBee, the experiments are conducted under various parameters, such as modulation schemes, SNR levels, as well as channel settings

Summary

Introduction

The demand for information has brought prosperity to network systems such as WiFi and zigbee, which have crowed the 2.4GHz ISM band where these networks operate at. The WiFi Access Points (APs) are widely used for ubiquitous Internet access. Benefit from the high frequency utilization, most of existing WiFi system, such. As IEEE 802.11g [1] system, are using OFDM communication scheme, and operating at the frequency range of 2.402 ∼ 2.482 GHz. An OFDM channel occupies a 20 MHz bandwidth and is divided into 64 orthogonal subcarriers, and use 52 of them for data transmission.

Results

Discussion

Conclusion