Spectrum management in wireless mesh network for cognitive radios

Abstract

The ever-growing demand of the spectrum for a widespread range of applications like personal, business, ISM etc. is increasing day by day. Electromagnetic radio spectrum is a natural but limited resource. The diverse wireless classifications are structured by static allocation policies. The assignment strategy makes the spectrum to divide into a substantial number of different ranges and the range is computed for the specific system, such as, Global System for Mobile communications (GSM) subscribers use 0.88GHz to 0.915 GHz for uplink and 0.925GHz to 0.960GHz for downlink, Universal Mobile Telecommunications System (UMTS) 3G use the bands 1.9GHz to 2.025GHz for uplink and 2.11GHz to 2.2 GHz for downlink. Surprisingly, the allocated spectrum is not completely utilized by users. There is an imperative need for dynamic allocation of the spectrum to combat the collective demand of limited resource. newlineThe recent survey statistics indicate that the utilization of the allocated spectrum is not constant. Some of the wireless applications are used partial and some wireless systems are heavily used and others poorly utilized. The international telecommunications union (ITU) and its Radiocommunication subcommittee (ITU-R) is a UN based authority for synchronizing spectrum allocation universally. In the USA, the Federal Communications Commission (FCC) [1] is a government agency accountable for regulating wireless spectrum. newlineThe spectrum scarcity is aroused because of not properly utilizing the available spectrum efficiently. Many modern wireless networks allow the increased number of users, but still not capable to meet the increased demand. A potential wireless technology Cognitive radio (CR) [2-5] was first perceived by Joseph Mitola III.According to Draft National Telecom Policy 2011, there is a need from Wireless Planning and Coordination wing (WPC) for unlicensed bands for the multimedia and internet application for better utilization of spectrum. There is also requirement to expand the unlicensed spectrum in the application like ISM bands, data telemetry, low power wireless devices, indoor services, broadband wireless communications personal communication etc. 40%-90% of wireless applications like mobile communication, wireless healthcare, broadband functions in unlicensed spectrum bands. There is a crucial need for smart and network conscious spectrum management. Cognitive radio is the emerging technology which will address the scarcity of resource and can meet the request using spectrum management. It involves identifying the idle licensed user channels and allocating the same to the unlicensed user without causing interference. The CR has the capability to shift to diverse portions of the radio spectrum soon after the spectrum holes/vacant channels create. There are many design issues like interference, end-to-end delay, newlineconnectivity, throughput, stability, and scalability to be addressed in channel assignment for multi radio WMN using CR. newline