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Channel allocation schemes

About: Channel allocation schemes is a research topic. Over the lifetime, 10656 publications have been published within this topic receiving 182117 citations.


Papers
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Proceedings ArticleDOI
Ihsan Akbar1, W.H. Tranter1
22 Mar 2007
TL;DR: This work uses hidden Markov models (HMMs) to model and predict the spectrum occupancy of licensed radio bands, and presents the performance of the proposed dynamic spectrum allocation algorithm when the channel state occupancy of primary users are assumed to be Poisson distributed.
Abstract: Cognitive radio networks can be designed to manage the radio spectrum more efficiently by utilizing the spectrum holes in primary users' licensed frequency bands. Recent studies have shown that the radio spectrum is poorly utilized by the licensed users even in urban geographical areas. This spectrum utilization can be improved significantly by making it possible for secondary users (who are not being served by the primary system) to access spectrum holes, i.e., frequency bands not used by licensed users. In this novel work, we use hidden Markov models (HMMs) to model and predict the spectrum occupancy of licensed radio bands. The proposed technique can dynamically select different licensed bands for its own use with significantly less interference from and to the licensed users. It is found that by predicting the duration of spectrum holes of primary users, the CR can utilize them more efficiently by leaving the band, that it currently occupies, before the start of traffic from the primary user of that band. We propose a simple algorithm, called the Markov-based channel prediction algorithm (MCPA), for dynamic spectrum allocation in cognitive radio networks. In this work, we present the performance of our proposed dynamic spectrum allocation algorithm when the channel state occupancy of primary users are assumed to be Poisson distributed. The impact of CR transmission on the licensed users is also presented. It is shown that significant SIR improvements can be achieved using HMM based dynamic spectrum allocation as compared to the traditional CSMA based approach. The results obtained using HMM are very promising and HMM can offer a new paradigm for predicting channel behavior in cognitive radio, an area that has been of much research interest lately.

221 citations

Proceedings ArticleDOI
05 Dec 2005
TL;DR: A novel layered graph is proposed to model the temporarily available spectrum bands, called spectrum opportunities (SOPs), and this layered graph model is used to develop effective and efficient routing and interface assignment algorithms to form near-optimal topologies for DSA networks.
Abstract: This paper studies a fundamental problem in dynamic spectrum access (DSA) networks: given a set of detected spectrum bands that can be temporarily used by each node in a DSA network, how to form a topology by selecting spectrum bands for each radio interface of each node, called topology formation in this paper. We propose a novel layered graph to model the temporarily available spectrum bands, called spectrum opportunities (SOPs) in this paper, and use this layered graph model to develop effective and efficient routing and interface assignment algorithms to form near-optimal topologies for DSA networks. We have evaluated the performance of our layered graph approach and compared it to a sequential interface assignment algorithm. The numerical results show that the layered graph approach significantly outperforms the sequential interface assignment

217 citations

Proceedings ArticleDOI
05 Dec 2005
TL;DR: In this article, the idle bandwidth in the current TV band assignments is quantified and a modified form of OFDM called Discontiguous OFDM (DOFDM) is proposed.
Abstract: Sharing spectrum with systems that employ frequency reuse over large geographical areas (e.g., TV stations) provides an opportunity to improve spectrum utilization. The Federal Communications Commission (FCC) is considering such sharing in the TV hands (2004). This technical and regulatory opportunity prompted the IEEE to create a new committee, 802.22, that will develop a wireless regional area network (WRAN) standard for operating on vacant TV channels. This paper quantifies the idle bandwidth in the current TV band assignments; although the TV station information incorporated here is specific to the United States, the methodology and findings should be relevant to a global audience. The methodology for this analysis is distinct from prior literature on spectrum use measurements and offers a complementary perspective. Furthermore, the statistics from the analysis point to the value of systems that can operate on discontiguous portions of the radio spectrum. One approach, a modified form of OFDM here termed Discontiguous OFDM (DOFDM), could be well-suited to this dynamic spectrum access application. This paper provides a preliminary description of a DOFDM prototype and describes special considerations for its implementation

216 citations

Journal ArticleDOI
TL;DR: A novel dynamic guard channel scheme is proposed which adapts the number of guard channels in each cell according to the current estimate of the handoff call arrival rate derived from the current number of ongoing calls in neighboring cells and the mobility pattern, so as to keep the handoffs call blocking probability close to the targeted objective.
Abstract: In future personal communications networks (PCNs) supporting network-wide handoffs, new and handoff requests will compete for connection resources in both the mobile and backbone networks. Forced call terminations due to handoff call blocking are generally more objectionable than new call blocking. The previously proposed guard channel scheme for radio channel allocation in cellular networks reduces handoff call blocking probability substantially at the expense of slight increases in new call blocking probability by giving resource access priority to handoff calls over new calls in call admission control. While the effectiveness of a fixed number of guard channels has been demonstrated under stationary traffic conditions, with nonstationary call arrival rates in a practical system, the achieved handoff call blocking probability may deviate significantly from the desired objective. We propose a novel dynamic guard channel scheme which adapts the number of guard channels in each cell according to the current estimate of the handoff call arrival rate derived from the current number of ongoing calls in neighboring cells and the mobility pattern, so as to keep the handoff call blocking probability close to the targeted objective while constraining the new call blocking probability to be below a given level. The proposed scheme is applicable to channel allocation over cellular mobile networks, and is extended to bandwidth allocation over the backbone network to enable a unified approach to prioritized call admission control over the ATM-based PCN.

213 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide theoretical insights and algorithmic solutions to jointly optimize power and channel allocation in non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) for utility maximization.
Abstract: Network capacity calls for significant increase for 5G cellular systems. A promising multi-user access scheme, non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC), is currently under consideration. In NOMA, spectrum efficiency is improved by allowing more than one user to simultaneously access the same frequency-time resource and separating multi-user signals by SIC at the receiver. These render resource allocation and optimization in NOMA different from orthogonal multiple access in 4G. In this paper, we provide theoretical insights and algorithmic solutions to jointly optimize power and channel allocation in NOMA. For utility maximization, we mathematically formulate NOMA resource allocation problems. We characterize and analyze the problems' tractability under a range of constraints and utility functions. For tractable cases, we provide polynomial-time solutions for global optimality. For intractable cases, we prove the NP-hardness and propose an algorithmic framework combining Lagrangian duality and dynamic programming (LDDP) to deliver near-optimal solutions. To gauge the performance of the obtained solutions, we also provide optimality bounds on the global optimum. Numerical results demonstrate that the proposed algorithmic solution can significantly improve the system performance in both throughput and fairness over orthogonal multiple access as well as over a previous NOMA resource allocation scheme.

212 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202315
202259
2021181
2020268
2019293
2018292