Traffic pattern prediction and performance investigation for cognitive radio systems

In this paper, we propose a technique for predicting the traffic pattern of primary users in cognitive radio systems. Cognitive radios enable sharing the frequency bands that are licensed to primary users. By forecasting the traffic pattern of primary users, secondary users can estimate the utilization of frequency bands and select one for radio transmission to reduce the frequency hopping rate (the rate of switching from one frequency band to another) and the interference effects, while maintaining a reasonable blocking rate. In this work, we propose an algorithm for the prediction of call arrival rate which exploits the periodicity of the traffic process. In addition, we present an approach for call holding time estimation. The results are incorporated to evaluate the probability of the availability of a frequency band within a time period. Setting a threshold on this probability maintains a tradeoff between the blocking rate of secondary users, interference effects on primary users and spectrum efficiency. Simulations are conducted to investigate the performance of cognitive radio systems with and without traffic prediction. © 2008 IEEE

Automatic construction of cognitive radio network

This paper presents a scheme for cognitive radio network construction. Incorporating the available spectrum, cognitive radio nodes automatically construct a local area network. The active cognitive radio nodes in an area form groups. Each group consists of a leader node, inter-group nodes and regular nodes. Inter-group nodes connect different groups to construct a network. Furthermore, the group leaders of different groups form virtual groups to facilitate the network management. The proposed scheme can also be used to construct large scale cognitive radio networks. Its applications include temporal network deployment in emergency situations and home appliance network construction. © 2008 IEEE

Distributed channel assignment in cognitive radio networks

Considering an ad hoc cognitive radio network, this paper presents channel assignment methods that can be used by a cognitive radio node to select a channel for communication. The proposed channel assignment methods aim to maximize spectral efficiency, minimize transmit power, or maximize data rate. When a number of available channels are detected, based on the proposed methods, a cognitive radio node can decide a suitable channel to use. These methods are executed distributively in cognitive radio nodes without using central controllers. This reduces the complexity of spectrum sharing in cognitive radio networks. Copyright © 2009 ACM

Cognitive radio based spectrum sharing: Evaluating channel availability via traffic pattern prediction

In this paper, a technique is proposed that enables secondary users to evaluate channel availability in cognitive radio networks. Here, secondary users estimate the utilization of channels via predicting the traffic pattern of primary user, and select a proper channel for radio transmission. The proposed technique reduces the channel switching rate of secondary users (the rate of switching from one channel to another) and the interference on primary users, while maintaining a reasonable call blocking rate of secondary users. © 2009 KICS

Connectivity analysis of group-based cognitive radio networks

Cognitive radio nodes can form a wireless network automatically based on the group concept: In a given area, cognitive radio nodes are assumed to be activated randomly. Activated cognitive radio nodes form multiple groups . Each group consists of a leader node, some bridge nodes and regular nodes. Leader node is capable of communicating with any group member node, and bridge nodes connect different groups to form a scalable network. With this concept, incorporating the available spectrum, cognitive radio nodes can form a network without the constraint of common channel availability. This paper first proposes a scheme for the node communication, and then based on this scheme, analyzes the numbers of nodes and channels required to maintain full connectivity of the cognitive radio network formed for emergency situation. Finally, this paper investigates the connectivity of the group-based cognitive radio network with arbitrary topology. © 2012 IEEE