Analysis of cognitive radio spectrum access with finite primary users and infinite secondary users

2010 ◽  
Author(s):  
Qiming Tian ◽  
Chuan Ma ◽  
Guanding Yu ◽  
Aiping Huang
Keyword(s):  
Cognitive Radio ◽  
Radio Spectrum ◽  
Spectrum Access ◽  
Secondary Users ◽  
Primary Users

scholarly journals Capacity optimization for radio resource allocation in cognitive networks

2021 ◽  
Author(s):  
Mohamed Elalem
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sharing ◽  
Cognitive Radio Network ◽  
Radio Spectrum ◽  
Opportunistic Spectrum Access ◽  
Effective Capacity ◽  
Radio Network ◽  
Spectrum Access ◽  
Primary Users ◽  
Access Model

With the rapid development of wireless services and applications, the currently radio spectrum is becoming more crowded. How to accommodate more wireless services and applications within the limited radio spectrum becomes a big challenge faced by modern society. Cognitive radio (CR) is proposed as a promising technology to tackle this challenge by introducing secondary users (SUs) to opportunistically or concurrently access the spectrum allocated to primary users (PUs). Currently, there are two prevalent CR models: the spectrum sharing model and the opportunistic spectrum access model. In the spectrum sharing model, the SUs are allowed to coexist with the PUs as long as the interferences from SUs do not degrade the quality of service (QoS) of PUs to an unacceptable level. In the opportunistic spectrum access model, SUs are allowed to access the spectrum only if the PUs are detected to be inactive. These two models known as underlay and overlay schemes, respectively. This thesis studies a number of topics in CR networks under the framework of these two schemes. First, studied cognitive radio transmissions under QoS delay constraints. Initially, we focused on the concept: effective capacity for cognitive radio channels in order to identify the performance in the presence of QoS constraints. Both underlay and overlay schemes are studied taking into consideration the activity of primary users, and assuming the general case of channel fading as Gamma distribution. For this setting, we further proposed a selection criterion by which the cognitive radio network can choose the adequate mode of operation. Then, we studied the cognitive radio transmissions focusing on Rayleigh fading channel and assumed that no prior channel knowledge is available at the transmitter and the receiver. We investigated the performance of pilot-assisted transmission strategies. In particular, we analyzed the channel estimation using minimum mean-square-error (MMSE) estimation, and analyzed efficient resource allocation strategies. In both cases, power allocations and effective capacity optimization were obtained. Effective capacity and interference constraint were analyzed in both single-band and multi-band spectrum sensing settings. Finally, we studied optimal access probabilities for cognitive radio network using Markov model to achieve maximum throughput for both CR schemes.

Introduction to Cognitive Radio Networks

2013 ◽  
pp. 1-30 ◽  
Author(s):  
Natarajan Meghanathan
Keyword(s):  
Cognitive Radio ◽  
Dynamic Spectrum Access ◽  
Dynamic Spectrum ◽  
Spectrum Access ◽  
Medium Access ◽  
Secondary Users ◽  
Comprehensive Review ◽  
Primary Users ◽  
Transmission Parameters ◽  
Perceived Availability

A cognitive radio (CR) is a radio that can change its transmission parameters based on the perceived availability of the spectrum bands in its operating environment. CRs support dynamic spectrum access and can facilitate a secondary unlicensed user to efficiently utilize the available underutilized spectrum allocated to the primary licensed users. A cognitive radio network (CRN) is composed of both the secondary users with CR-enabled radios and the primary users whose radios need not be CR-enabled. In this chapter, the authors provide an exhaustive analysis of the issues and the state-of-the-art literature solutions available with regards to the following four layers of the TCP/IP protocol layer stack, in the context of CRNs: physical layer (spectrum sensing), medium access control, routing, and transport layers. We discuss the various techniques/mechanisms/protocols that have been proposed for each of these four layers, in the context of CRNs. In addition to the above, we discuss in detail several security attacks that could be launched on CRNs and the countermeasure solutions that have been proposed to avoid or mitigate them. This chapter serves as a good comprehensive review and analysis of all the critical aspects for CRNs, and would lay a strong foundation for someone to further delve onto any particular aspect in greater depth.

scholarly journals Session based cooperation in cognitive radio networks: network level approach

2020 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Sunil Ghildiyal
Keyword(s):  
Resource Allocation ◽  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Spectrum Sharing ◽  
Radio Networks ◽  
Spectrum Access ◽  
Secondary Users ◽  
Generation Spectrum ◽  
Primary Users ◽  
Present Generation

<p>The cognitive radio prototype performance is to alleviate the scarcity of spectral resources for wireless communication through intelligent sensing and quick resource allocation techniques. Secondary users (SU’s) actively obtain the spectrum access opportunity by supporting primary users (PU’s) in cognitive radio networks (CRNs). In present generation, spectrum access is endowed through cooperative communication based link-level frame-based cooperative (LLC) principle. In this SUs independently act as conveyors for PUs to achieve spectrum access opportunities. Unfortunately, this LLC approach cannot fully exploit spectrum access opportunities to enhance the throughput of CRNs and fails to motivate PUs to join the spectrum sharing processes. Therefore to overcome this con, network level cooperative (NLC) principle was used, where SUs are integrated mutually to collaborate with PUs session by session, instead of frame based cooperation for spectrum access opportunities. NLC approach has justified the challenges facing in LLC approach. In this paper we make a survey of some models that have been proposed to tackle the problem of LLC. We show the relevant aspects of each model, in order to characterize the parameters that we should take in account to achieve a spectrum access opportunity.</p>

scholarly journals Capacity optimization for radio resource allocation in cognitive networks

2021 ◽  
Author(s):  
Mohamed Elalem
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sharing ◽  
Cognitive Radio Network ◽  
Radio Spectrum ◽  
Opportunistic Spectrum Access ◽  
Effective Capacity ◽  
Radio Network ◽  
Spectrum Access ◽  
Primary Users ◽  
Access Model

With the rapid development of wireless services and applications, the currently radio spectrum is becoming more crowded. How to accommodate more wireless services and applications within the limited radio spectrum becomes a big challenge faced by modern society. Cognitive radio (CR) is proposed as a promising technology to tackle this challenge by introducing secondary users (SUs) to opportunistically or concurrently access the spectrum allocated to primary users (PUs). Currently, there are two prevalent CR models: the spectrum sharing model and the opportunistic spectrum access model. In the spectrum sharing model, the SUs are allowed to coexist with the PUs as long as the interferences from SUs do not degrade the quality of service (QoS) of PUs to an unacceptable level. In the opportunistic spectrum access model, SUs are allowed to access the spectrum only if the PUs are detected to be inactive. These two models known as underlay and overlay schemes, respectively. This thesis studies a number of topics in CR networks under the framework of these two schemes. First, studied cognitive radio transmissions under QoS delay constraints. Initially, we focused on the concept: effective capacity for cognitive radio channels in order to identify the performance in the presence of QoS constraints. Both underlay and overlay schemes are studied taking into consideration the activity of primary users, and assuming the general case of channel fading as Gamma distribution. For this setting, we further proposed a selection criterion by which the cognitive radio network can choose the adequate mode of operation. Then, we studied the cognitive radio transmissions focusing on Rayleigh fading channel and assumed that no prior channel knowledge is available at the transmitter and the receiver. We investigated the performance of pilot-assisted transmission strategies. In particular, we analyzed the channel estimation using minimum mean-square-error (MMSE) estimation, and analyzed efficient resource allocation strategies. In both cases, power allocations and effective capacity optimization were obtained. Effective capacity and interference constraint were analyzed in both single-band and multi-band spectrum sensing settings. Finally, we studied optimal access probabilities for cognitive radio network using Markov model to achieve maximum throughput for both CR schemes.

scholarly journals Opportunistic Channel Allocation Model in Collocated Primary Cognitive Network

2020 ◽  
Vol 5 (5) ◽  
pp. 995-1012
Author(s):  
Mangala Prasad Mishra ◽  
Sunil Kumar Singh ◽  
Deo Prakash Vidyarthi
Keyword(s):  
Cognitive Radio ◽  
Channel Allocation ◽  
Radio Spectrum ◽  
Base Stations ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Primary Users ◽  
Proposed Model ◽  
Radio Resources ◽  
Primary Base

The growing demand of radio spectrum to facilitate the primary/secondary users in a cellular network is a challenging task. Many channel allocation models, applying cognition, have been proposed to increase the radio spectrum utilization. The proposed model peruses three types of users: primary users (PUs), opportunistic primary users (OPUs), and secondary users (SUs) that use the radio resources in collocated primary base stations. Out of these users, the opportunistic primary users and secondary users may request for handover as per their requirements. The objective of the model is to enhance the radio spectrum utilization by the opportunistic utilization of radio resources by OPUs and by enabling cognitive radio base stations to collect free channel information dynamically. The cognitive radio base station maintains the centralized free channel at collocated primary base stations to facilitate the SUs opportunistically. The proposed channel allocation technique maintains the Quality of Experience (QoE) of the users as well. The performance analysis of the model is done by simulation which diversifies the importance of the proposed model in the view of minimum blocked services.

Throughput-Efficient Spectrum Access in Cognitive Radio Networks

2015 ◽  
pp. 454-477
Author(s):  
Raza Umar ◽  
Wessam Mesbah
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Coalition Formation ◽  
Dynamic Spectrum Access ◽  
Radio Spectrum ◽  
Radio Networks ◽  
Spectrum Access ◽  
Secondary Users ◽  
Network Partition ◽  
Game Theoretic

Cognitive radio based on dynamic spectrum access has emerged as a promising technology to meet the insatiable demand for radio spectrum by the emerging wireless applications. In this chapter, the authors address the problem of throughput-efficient spectrum access in Cognitive Radio Networks (CRNs) using Coalitional Game-theoretic framework. They model the problem of joint Coalition Formation (CF) and Bandwidth (BW) allocation as a CF game in partition form with non-transferable utility and present a variety of algorithms to dynamically share the available spectrum resources among competing Secondary Users (SUs). First, the authors present a centralized solution to reach a sum-rate maximizing Nash-stable network partition. Next, a distributed CF algorithm is developed through which SUs may join/leave a coalition based on their individual preferences. Performance analysis shows that the CF algorithms with optimal BW allocation provides a substantial gain in the network throughput over existing coalition formation techniques as well as the simple cases of singleton and grand coalition.

scholarly journals 5G cognitive radio system design with new algorithm asynchronous spectrum sensing

2021 ◽  
Vol 10 (4) ◽  
pp. 2046-2054
Author(s):  
Mohammed Mehdi Saleh ◽  
Ahmed A. Abbas ◽  
Ahmed Hammoodi
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Energy Detection ◽  
Primary User ◽  
Spectrum Access ◽  
Secondary Users ◽  
Radio System ◽  
Wireless Applications ◽  
Fifth Generation ◽  
Time Required

Due to the rapid increase in wireless applications and the number of users, spectrum scarcity, energy consumption and latency issues will emerge, notably in the fifth generation (5G) system. Cognitive radio (CR) has emerged as the primary technology to address these challenges, allowing opportunist spectrum access as well as the ability to analyze, observe, and learn how to respond to environmental 5G conditions. The CR has the ability to sense the spectrum and detect empty bands in order to use underutilized frequency bands without causing unwanted interference with legacy networks. In this paper, we presented a spectrum sensing algorithm based on energy detection that allows secondary user SU to transmit asynchronously with primary user PU without causing harmful interference. This algorithm reduced the sensing time required to scan the whole frequency band by dividing it into n sub-bands that are all scanned at the same time. Also, this algorithm allows cognitive radio networks (CRN) nodes to select their operating band without requiring cooperation with licensed users. According to the BER, secondary users have better performance compared with primary users.

The Impact of Regulations on the Business Case for Cognitive Radio

2013 ◽  
pp. 142-170
Author(s):  
Peter Anker
Keyword(s):  
Cognitive Radio ◽  
Potential Application ◽  
Business Case ◽  
Radio Spectrum ◽  
Considerable Degree ◽  
Regulatory Regime ◽  
Spectrum Access ◽  
The Impact

Cognitive Radio holds an interesting promise for improved utilisation of the radio spectrum. However, there is a considerable degree of uncertainty regarding the potential application of cognitive radio. One of the reasons for this uncertainty is the need for changes in the regulatory regime to allow for more dynamic forms of spectrum access. In addressing the necessary changes in regulations, the regulator should be well aware of the perspective of the entrepreneur. Eventually, it is the entrepreneur who invests in CR technology and thereby realises the goal of improved utilisation of the radio spectrum. This chapter addresses the impact on the business case for cognitive technologies of the regulatory regime and the choices on the fundamental CR technology that regulators will have to make.

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