Performance Enhancement of TCP in Cognitive Mobile IP based Networks

In traditional mobile IP, packet drops mainly occur due to mobile handover from one sub-network to another sub-network and congested buffer overflow. Dynamic spectrum access and spectrum mobility in Cognitive Mobile IP introduces additional in-flight packet drops due to PU active in current CR transmission. Spectrum mobility packet drops in route optimization based CR mobile IP and smooth handover will degrade the performance of Transmission Control Protocol (TCP). To date, number of packet buffering and packet forwarding methodologies were proposed to prevent the performance degradation due to node handover packet drops. But, it is crucial to reduce spectrum handover packet drops during PU active. Moreover, CR users keep on change its point-of-attachment in licensed channel where PU can be active in current CR handover channel which results in buffered packet drops. Subsequently, it leads to decrease the congestion window size at the sender CR-TCP which will severely degrade the performance of TCP even though there is no congestion within the network. In proposed work, PU free channel list (PCL), packet and priority buffers with modification of registration request messages are done to enhance the performance of CR-TCP protocol.