A Survey on Performance Analysis of Distributed Channel Allotment Approaches for Wireless Sensor Networks with Cognitive radio capabilities

In wireless communication, the need for frequency spectrum is rising day by day. The existing accessible frequency bands can be used in a fixed way by Wireless Sensor Networks (WSNs). One needs the permission of the particular authority to use the frequency spectrum except for the industrial, scientific and medical(ISM) frequency channels of the spectrum. As the price of procuring permission for authorized spectrum usage is high, several researchers and manufacturers have paid attention to build-up gadgets for ISM frequency bands. Consequently, ISM frequency bands are congested resulting in the occurrence of coincidence problem and on the other hand many authorized frequency bands are either not used or used less leading to spectrum underutilization. To overcome the crisis, a new aspect must be included in Wireless Sensor Networks (WSNs) to diminish the inefficiency of spectrum underutilization as well as intrusion incorporated by other uses. The answer to the problem of frequency spectrum underutilization is given by incorporating Cognitive Radio (CR) technology to WSNs towards supporting the wireless sensor nodes with the ability of Opportunistic Spectrum Access (OSA). OSA permits the usage of the suitable frequency spectrum band according to the requirements of the application by using the unexploited frequency spectrum opportunistically, permitting the unauthorized users to use several authorized frequency channels as CR has the capability to recognize the unused spectrum in the authorized and unauthorized frequency spectrum bands. The flexibility has been used to alter the transmission parameters each time when a new channel is selected and minimize power utilization. The reduction of power utilization through OSA does not merely expand the life-time of battery constrained wireless sensor nodes, besides restricts the power usage on the whole by the wireless sensor network. The CR users can sense the identical unoccupied frequency band resulting in the utilization of energy in probing new unoccupied bands. Thus there is a requirement for effective frequency channel allotment in CRWSNs. But of the several approaches evolved to attain the familiarity of the frequency spectrum for cognitive radios, only a few schemes have looked at the problem of power usage, which is a serious problem for cognitive radio wireless sensor networks (CRWSNs). Therefore, the channel allotment approaches are designed for the efficient utilization of bands to enhance the energy competence and thereby increase the performance, QoS, reliability, network lifetime and diminish the internodes and internetwork interference, etc. In this work, a survey has been undertaken for distributed channel allocation schemes for Cognitive Radio Wireless Sensor Networks.