Coexistence Of ZigBee Research Articles

Mitigating Cross-Technology Interference Through Fast Signal Identification

With the prosperity of Internet of Things, a large number of heterogeneous wireless devices share the same unlicensed spectrum, leading to severe cross-technology interference (CTI). Especially, the transmission power asymmetry of heterogeneous devices will further deteriorate this problem, as the high-power devices (like WiFi) always corrupt the ongoing transmissions of low-power devices (like ZigBee), because the energy of the ZigBee signal perceived by WiFi is too weak to achieve the CCA (Clear Channel Assessment) threshold and the channel is considered to be idle. This paper proposes an enhanced CCA (E-CCA) mechanism to mitigate CTI in WiFi and ZigBee coexistence networks. E-CCA contains ZShark which can identify signals within a tolerable time duration. It also contains a MAC layer design, with which a WiFi device can still determine the channel to be busy when the detected energy is below the CCA threshold while a ZigBee signal is identified, thus to avoid CTI to ZigBee transmissions. We set up a testbed based on USRP B200 and TelosB to collect data and evaluate the performance of ZShark. We further evaluate the performance of E-CCA through both theoretical analysis and simulations on NS-3. The results show significant performance improvement of ZigBee.

Coexistence of Zigbee and Wi-Fi Networks in Machine-to-Machine Home System

Coexistence of Zigbee and Wi-Fi Networks in Machine-to-Machine Home System

An adaptive hybrid ARQ method for coexistence of ZigBee and WiFi

With the rapid development of modern communication technology, all kinds of radio technologies emerge endlessly. As different wireless networks share the same spectrum, coexistence of the heterogeneous networks becomes a challenging problem, especially the coexistence between ZigBee and WiFi. Much research has been done to solve this problem, and some coexistence methods have been proposed, such as the spectrum allocation, power control and so on. However, the proposed methods are either too complex to implement or need additional hardware cost. This paper proposes an easy and feasible method called AHA for ZigBee. The method modifies the current FEC coding method and additionally colligates energy sensing and adaptive retransmission. By implementing the method on ZigBee using USRP N210 devices, it is demonstrated that AHA effectively improves the communication performance of ZigBee under WiFi interference.

An adaptive hybrid ARQ method for coexistence of ZigBee and WiFi

An adaptive hybrid ARQ method for coexistence of ZigBee and WiFi

Taming Cross-Technology Interference for Wi-Fi and ZigBee Coexistence Networks

Recent studies show that Wi-Fi interference has been a major problem for low power urban sensing technology ZigBee networks. Existing approaches for dealing with such interferences often modify either the ZigBee nodes or Wi-Fi nodes. However, massive deployment of ZigBee nodes and uncooperative Wi-Fi users call for innovative cross-technology coexistence without intervening legacy systems. In this work, we investigate the Wi-Fi and ZigBee coexistence when ZigBee is the interested signal. Typically, the duration of transmitting a ZigBee data packet is longer than that of a Wi-Fi packet. Mitigating short duration Wi-Fi interference (called flash ) in long duration ZigBee data (called smog ) is challenging. To address these challenges, we propose ZIMO: a sink-based MIMO design for harmony coexistence of ZigBee and Wi-Fi networks with the goal of protecting the ZigBee data packets from being interfered by high-power cross-technology signals. The key insight is to properly exploit opportunities resulted from differences between Wi-Fi and ZigBee, and bridge the gap between interested data and cross technology signals. Also, extracting the channel coefficient of Wi-Fi and ZigBee will enhance other coexistence technologies such as TIMO [1] . We implement a prototype in GNURadio-USRP N200, and our extensive evaluations under real wireless conditions show that ZIMO can improve ZigBee network throughput up to 1.9 $\times$ , with 1.5 $\times$ in media, and 1.1 $\times$ to 1.9 $\times$ for Wi-Fi network as byproduct in ZigBee signal recovery.

Implementation of multi-channel technology in ZigBee wireless sensor networks

This paper proposes a multi-channel ZigBee wireless sensor network (WSN) for robust data transmission. This study sought to increase the packet delivery ratio (PDR) through the application of multi-channel technology. Based on a cluster-tree construction protocol, we implemented a multi-channel time division multiple-access scheme using hardware devices. Furthermore, ZigBee and wireless LAN (WLAN) both operate on the 2.4 GHz band, referred to as the industrial, scientific, and medical unlicensed band. As a result, ZigBee faces severe interference problems in the presence of WLAN. In this study, we developed an interference avoidance method to improve conditions for the coexistence of ZigBee and WLAN and then conducted experiments using a practical network implementation to evaluate the resulting performance. Our experiment results demonstrate considerable improvements in the PDR of ZigBee transmission in an environment with interference from WLAN.

Enabling Coexistence of ZigBee and WiFi

Enabling Coexistence of ZigBee and WiFi