Robust End-to-End QoS Maintenance in Non-Contiguous OFDM Based Cognitive Radios

Mwangoka, Joseph; Letaief, Khaled B.; Cao, Zhigang

doi:10.1109/icc.2008.547

Cited by 10 publications

(39 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, for the desired level of the blocking probability (e.g., < 0.15), the blocking is due to serving other RT users. This explains why the overall blocking probability is approximated as P B ≈ P B bs in the analysis, which is true for all practical values of the used parameters as can be calculated using (11) and (14) for P Bun and P B bs , respectively. Furthermore, there is an optimum number of the admitted RT users that maximizes the average number of the served RT users considering the required blocking probability threshold, which necessitates integrating the QoS provisioning with the call admission control.…”

Section: Numerical and Simulation Resultsmentioning

confidence: 99%

“…The first category investigates the Medium Access Control (MAC) protocol and opportunistic scheduling design, which can provide QoS for the SUs in different secondary network models [3]- [8]. The second category focuses on power allocation schemes that are aware of the QoS for different scenarios of CRNs [9]- [11]. The third category develops different call admission control and channel allocation schemes to guarantee certain QoS requirements of the SUs [12]- [20].…”

mentioning

confidence: 99%

See 1 more Smart Citation

QoS Provisioning for Heterogeneous Services in Cooperative Cognitive Radio Networks

Alshamrani

Shen

Xie

2011

IEEE J. Select. Areas Commun.

View full text Add to dashboard Cite

Abstract-In this paper, we propose a spectrum allocation framework that jointly considers the Quality-of-Service (QoS) provisioning for heterogeneous secondary Real-Time (RT) and Non-Real Time (NRT) users, the spectrum sensing, spectrum access decision, channel allocation, and call admission control in distributed cooperative Cognitive Radio Networks (CRNs). Giving priority to the RT users with QoS requirements in terms of the dropping and blocking probabilities, a number of the identified available channels are allocated to the optimum number of the RT users that can be admitted into the network, while the remaining identified available channels are allocated adaptively to the optimum number of the NRT users considering the spectrum sensing and utilization indispensability. Extensive analytical and simulation results are provided to demonstrate the effectiveness of the proposed QoS-based spectrum resource allocation framework.

show abstract

Section: Numerical and Simulation Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

QoS Provisioning for Heterogeneous Services in Cooperative Cognitive Radio Networks

Alshamrani

Shen

Xie

2011

IEEE J. Select. Areas Commun.

View full text Add to dashboard Cite

show abstract

“…. , T , we have an instance of Problem OP3 in which r t,REQ k is calculated using (16) with m CR,t equal to the number of available subchannels in slot t and m(t, t + T k,i − 1) can be estimated as discussed in Sect. 3.2.…”

Section: Op3mentioning

confidence: 99%

“…In [16], the average rate of the CRU in a single user case is maintained and the rate variance is minimized, subject to power constraints. To the best of our knowledge, there is no published work on QoS provisioning for realtime applications in OFDM-based CR systems.…”

mentioning

confidence: 99%

Cross-layer resource allocation for real-time services in OFDM-based cognitive radio systems

Zhang

Leung

2009

Telecommun Syst

View full text Add to dashboard Cite

The resource allocation problem on the downlink of a multiuser OFDM-based cognitive radio (CR) system is formulated using a cross-layer (MAC and PHY layers) approach with the aim of satisfying quality of service (QoS) requirements in real-time applications. The number of subchannels available to the CR system is time-varying as a result of the stochastic nature of the activities of the primary users (PUs). The MAC layer QoS requirements are dynamically converted to PHY layer rate requirements; the conversion depends on the delivery status of queued packets as well as the number of available subchannels. Simulation results show that the proposed cross-layer resource allocation algorithm can provide substantial transmit power reductions compared to existing PHY layer and MAC layer solutions designed for multiuser OFDM systems.

show abstract

“…Currently, to the best of authors' knowledge, there are few studies on quality of service (QoS) support in OFDMA-based CR systems. The QoS designs in [7,8] for CR systems only considered non-real-time applications. Up to now, the study on the spectrum underlay sharing is also sparse.…”

Section: Introductionmentioning

confidence: 99%

Joint cross-layer resource allocation and interference avoidance with QoS support for cognitive radio systems

Peng

Fujii

2012

J Wireless Com Network

View full text Add to dashboard Cite

In this article, we study the coexistence and optimization of a centralized orthogonal frequency-division multiple access-based multiuser cognitive radio (MCR) system which coexists with a cellular primary system (PS). Two different spectrum sharing methods, i.e., the spectrum underlay/overlay, are utilized for different coexistent frameworks, in which, the sharing method is adapted to one of them based on the distance between two base stations and the interference limit in the PS. We consider a PS-assistance-based coexistent architecture and propose a joint power control and interference management method to avoid unacceptable interference to primary users (PU). Firstly, the relationship between power limits at secondary users (SU) and interference margin at PUs can be obtained. Then, to provide the SUs with satisfactory quality of service (QoS), and optimize the sum rate of the MCR system as well, a constrained two-variable nonlinear optimization problem (OP) is formulated. We solve this OP by (i) simplifying the QoS constraints from medium access control-layer to physical-layer based on a crosslayer approximation; and (ii) using the Lagrangian duality based technique to solve the simplified OP, and iterative water-filling is implemented to find the optimal power and subcarrier allocation. Simulation results show that, compared to the conventional designs, our algorithm achieves significant higher throughput and can guarantee the required signal to interference plus noise ratio of the PUs and the QoS of the SUs well. Moreover, compared to the spectrum overlay sharing method, the spectrum underlay & overlay can provide substantial higher spectrum efficiency.

show abstract

Robust End-to-End QoS Maintenance in Non-Contiguous OFDM Based Cognitive Radios

Cited by 10 publications

References 11 publications

QoS Provisioning for Heterogeneous Services in Cooperative Cognitive Radio Networks

QoS Provisioning for Heterogeneous Services in Cooperative Cognitive Radio Networks

Cross-layer resource allocation for real-time services in OFDM-based cognitive radio systems

Joint cross-layer resource allocation and interference avoidance with QoS support for cognitive radio systems

Contact Info

Product

Resources

About