Interference Mitigation Techniques for Unlicensed Frequency Band in Wireless Ad Hoc Networks

Abstract

ABSTRACT newlineWith the advent of wireless ad hoc network, a self-configuring infrastructure less network with heterogeneous mobile devices connected by wireless medium, which is known for its characterization of highly dynamic topology, limited bandwidth and power consumption proliferate the communication technologies worldwide. The role of 2.4 GHz Industrial, Scientific, and Medical (ISM) band in this wireless communication is growing day by day. The growth of this unlicensed band is supported by two emerging wireless technologies namely Wireless Personal Area Network (WPAN) and Wireless Local Area Network (WLAN). newlineBluetooth devices led the WPAN category which is used for short-range wireless communications. Most of the Bluetooth devices are designed for cable replacement applications, with a short range of 8-10 meters with a throughput less than 750 Kbps. In contrast to WPAN, WLAN category in general and Wi-Fi in particular offers a minimum throughput of 11 Mbps and a range of approximately 100 meters. Also in the varying signal environment, coexistence of non-homogeneous wireless technologies is unavoidable. To allow coexistence, they must never use the same frequency at the same time, which is a major problem that both WPAN and WLAN face. Bluetooth and Wi-Fi devices in wireless ad hoc network cause interference with each other, increasingly as they approach each other. Interference plays a vital role in disturbing the data transmission capacity, device discovery and progress in communication systems. Hence, the foremost objective of this work is to provide a hybrid algorithm to mitigate the above discussed interference issues of WPAN and WLAN during their connectivity to heterogeneous devices at the same time adjusting its connectivity operation based on the current conditions of the environment, whilst maintaining the operational requirements of the system. newlineThis research work proposes an hybrid algorithm called as Frequent Spatial and Temporal algorithm , which aims to provide the architecture that enables diverse wireless networks competing for resources to actively exchange information and perform joint optimization in light of changing environmental and workload conditions, resulting in an improvement in the performance metrics of choice. The proposed algorithm principle is based on the transmission power, receiving power, packet time to live and alternate path in the wireless ad hoc network environment. newlineFrom the experimental setup and study, this work identifies that WLAN and WPAN newlineVill in the wireless network causes interference with each other and this interference causes severe performance degradations in terms of Normalized Routing Overhead, Throughput, Average Energy and Packet Delivery Ratio. The proposed algorithm is tested with various extensive simulations on unipath and multipath ad hoc routing protocol for the above parameters in the wireless ad hoc network environment and the newlineresults shows that there is improved performance in the environment. newline newline