scholarly journals Transmit power control and data rate enhancement in cognitive radio network using computational intelligence

Author(s):  
Paurav Goel ◽  
Avtar Singh ◽  
Ashok Goel

Underutilized radio frequencies are the chief apprehension in advance radio communication. The radio recourses are sparse and costly and their efficient allocation has become a challenge. Cognitive radio networks are the ray of hope. Cognitive radio networks use dynamic spectrum access technique to opportunistically retrieve and share the licensed spectrum. The licensed users are called primary users and the users that opportunistically access the licensed spectrum all called secondary users. The proposed system is a feedback system that work on demand and supply concept, in which secondary receivers senses the vacant spectrum and shares the information with the secondary transmitters. The secondary transmitters adjust their transmission parameters of transmit power and data rate in such a way that date rate is maximized. Two methods of spectrum access using frequency division multiple access (FDMA) and Time division multiple access (TDMA) are discussed. Interference temperature limit and maximum achievable capacity are the constraints that regulate the entire technique. The aim of the technique is to control the transmitter power according to the data requirements of each secondary user and optimizing the resources like bandwidth, transmit power using machine learning and feed forward back propagation deep neural networks making full use of the network capacity without hampering the operation of primary network.

2019 ◽  
Vol 16 (12) ◽  
pp. 34-46
Author(s):  
Ehab F. Badran ◽  
Amr A. Bashir ◽  
Amira I. Zaki ◽  
Waleed K. Badawi

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3800
Author(s):  
Xiang Xiao ◽  
Fanzi Zeng ◽  
Zhenzhen Hu ◽  
Lei Jiao

Cognitive radio networks (CRNs), which allow secondary users (SUs) to dynamically access a network without affecting the primary users (PUs), have been widely regarded as an effective approach to mitigate the shortage of spectrum resources and the inefficiency of spectrum utilization. However, the SUs suffer from frequent spectrum handoffs and transmission limitations. In this paper, considering the quality of service (QoS) requirements of PUs and SUs, we propose a novel dynamic flow-adaptive spectrum leasing with channel aggregation. Specifically, we design an adaptive leasing algorithm, which adaptively adjusts the portion of leased channels based on the number of ongoing and buffered PU flows. Furthermore, in the leased spectrum band, the SU flows with access priority employ dynamic spectrum access of channel aggregation, which enables one flow to occupy multiple channels for transmission in a dynamically changing environment. For performance evaluation, the continuous time Markov chain (CTMC) is developed to model our proposed strategy and conduct theoretical analyses. Numerical results demonstrate that the proposed strategy effectively improves the spectrum utilization and network capacity, while significantly reducing the forced termination probability and blocking probability of SU flows.


2017 ◽  
Vol 67 (2) ◽  
pp. 217-229 ◽  
Author(s):  
Yaser Jararweh ◽  
Haythem A. Bany Salameh ◽  
Abdallah Alturani ◽  
Loai Tawalbeh ◽  
Houbing Song

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