The Internet of Things (IoT), which has recently attracted attention as the next-generation IT industry, is technologies and services closing the gap between the real word and virtual word. It is based on a wired and wireless network platform that can connect things for many types of applications, involving all kinds of devices and objects like RFID and intelligent devices.
However, it is challenging to implement the IoT platform because of the heterogeneity of the networks. Particularly, ZigBee which is widely used for the applications that do not need high bandwidth but need low latency and very low energy consumption for long battery life and for large device arrays. Nevertheless, its transmission may be significantly harmed due to Wi-Fi with the relatively much higher power, and this is one of the reasons making the platform implementation difficult.
This paper presents a method reducing the error rate of the ZigBee transmission which can relatively be affected by the interference by IEEE 802.11 b/g (Wi-Fi) network. The basic idea is to find the slot time when ZigBee can transmit by analyzing the BEB (Binary Exponential Backoff) algorithm of the 802.11 DCF (Distributed Coordination Function), and an actual transmission happens stochastically using the p-Persistent CSMA model. A ZigBee coordinator will attempt transmission by parameter p, the probability with which a packet is transmitted when the channel is idle, and defer by probability (1?p). In addition, we dynamically derive the code rate that should be employed to recover errors with the Reed-Solomon coding.
To evaluate the proposed scheme, we investigated it in various networks on the Matlab. We compared in terms of the successful transmission rate. The simulation results show that it guarantees high channel utilization of the ZigBee by overcoming Wi-Fi interference in the 2.4 GHz frequency band.