Spectrum aggregation in cognitive radio network

Cognitive Radio is an emerging technology to reduce the problem of spectrum scarcity for the development of wireless communication by utilizing the continuous and wide spectrum resources. There exist two methods by which one can utilize the resources in Cognitive Radio Network efficiently. First is cooperative routing and the other is spectrum aggregation. This paper consists of an overview of the following spectrum aggregation algorithms and protocol: Aggregation Aware Spectrum Assignment (AASA), Prediction-based Spectrum Aggregation (PSA), Channel Aggregation (CA), Channel Characteristic Aware Spectrum Aggregation (CCASA) and Spectrum Aggregation-Based Co-operative Routing Protocol (SACRP) that has been proposed in the field of aggregation of spectrum based on different parameters such as end to end delay, reliability, throughput, energy efficiency etc. This method allows a user to utilize the multiple spectrum bands in order to meet their demand of large bandwidths so that the problem of spectrum scarcity can be reduced and the system performance can be enhanced.