A modified continuous-time Markov chain, for the prioritized spectrum access over cognitive radio ad-hoc networks
Sanaz Pashmforoush, Azadeh Alsadat Emrani Zarandi · International Journal of Electronics · 2021
Cognitive Radio Ad-hoc Network (CRAHN) is one of the building blocks of heterogeneous networks to improve accessibility and spectral efficiency. The prioritized spectrum access is the key to maintain the efficiency of CRAHN. However, in CRAHN, TCP results in severe throughput reduction since it cannot differentiate between the packet loss due to SU’s transmission-blocking and packet loss due to congestion. In this paper, two significant events are investigated that caused secondary user blocking. Besides, using a Continuous-Time Markov chain (CTMC), we develop an analytical model to estimate the TCP throughput and end to end delay. The experimental results based on the NS2 confirm the accuracy of the proposed model and show that the throughput and the average end-to-end delay are improved based on the proposed CTMC model comparing with some transport protocol in the cognitive radio networks. The performance results through simulation show that the proposed model not only provides less energy consumption, also achieves up to 40% and 20% improvement of the throughput comparing with the classical TFRC and TFRC-CR, respectively.