An Enhanced TCP for Optimizing Channel Utilization in Dynamic Spectrum Access Networks

Author(s):  
Menglong Li ◽  
Kai Shi ◽  
Sheng Lin ◽  
Jinsong Wang ◽  
Chunyan Hou ◽  
...  

Dynamic Spectrum Access (DSA) network grows rapidly in recent years. It is proposed to solve the problem of reasonable utilization of wireless spectrum resources. DSA is a new spectrum sharing paradigm which takes advantage of spectrum holes to ease the spectrum shortage problem and improve the spectrum utilization. However, due to the frequent spectrum switch, the performance of TCP will degrade greatly in the DSA network, and thus the channel is unutilized. To tackle with this problem and improve high throughput performance, this paper proposes a protocol called TCP WSP based on the assumption that there will be a Wide Stationary Process (WSP) between two spectrum switches. Then the authors propose a mechanism to predict the spectrum switch and adjust the sending rate of TCP based on the prediction to optimize channel utilization in DSA networks. They implement our mechanism on NS2 simulator, and the results show that their mechanism can achieve high throughput performance.

Author(s):  
Yogesh Kondareddy ◽  
Alireza Babaei ◽  
Prathima Agrawal

Transmission Control Protocol (TCP) is the most commonly used transport protocol on the Internet. All indications assure that it will be an integral part of the future Internetworks. In this chapter, the authors present how regular TCP, which was designed for wired networks, is not suitable for dynamic spectrum access networks. They develop an analytical model to estimate the TCP throughput of dynamic spectrum access networks. Dynamic spectrum access networks deal with opportunistic spectrum access leading to greater utilization of the spectrum. The extent of utilization depends on the primary user’s traffic and also on the way the spectrum is accessed by the primary and secondary users. The proposed model considers primary and secondary user traffic in estimating the TCP throughput by modeling the spectrum access using continuous-time Markov chains, thus providing more insight on effect of dynamic spectrum access on TCP performance than the existing models.


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