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Proceedings ArticleDOI

Throughput Analysis of a Energy Harvesting Cooperative Cognitive Radio Network

TL;DR: In this paper, energy harvesting cooperative cognitive radio (CR) network is studied under a collision constraint of PU and influence of an energy allocation parameter and sensing time on throughput performance is studied.
Abstract: In this paper, energy harvesting cooperative cognitive radio (CR) network is studied under a collision constraint of PU. Optimal numbers of CRs cooperate in transmission of primary user (PU), if it remains present in the given channel; otherwise all the CRs transmit their own data in time division scheme. The harvested energy at CR is divided into two parts, one part is allocated for cooperation in PU transmission and the other part is used for its own transmission. The allocation of energy is based on the targeted CR throughput. Influence of an energy allocation parameter and sensing time on throughput performance is studied under the random behaviour of PU.
Citations
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Journal ArticleDOI
20 Jun 2021-Entropy
TL;DR: In this paper, a spectrum sharing protocol for a cooperative cognitive radio network based on non-orthogonal multiple access technology is proposed, where the base station (BS) transmits the superimposed signal to the primary user and secondary user with/without the assistance of a relay station (RS) by adopting the decode-and-forward technique.
Abstract: In this paper, we propose a spectrum-sharing protocol for a cooperative cognitive radio network based on non-orthogonal multiple access technology, where the base station (BS) transmits the superimposed signal to the primary user and secondary user with/without the assistance of a relay station (RS) by adopting the decode-and-forward technique. RS performs discrete-time energy harvesting for opportunistically cooperative transmission. If the RS harvests sufficient energy, the system performs cooperative transmission; otherwise, the system performs direct transmission. Moreover, the outage probabilities and outage capacities of both primary and secondary systems are analyzed, and the corresponding closed-form expressions are derived. In addition, one optimization problem is formulated, where our objective is to maximize the energy efficiency of the secondary system while ensuring that of the primary system exceeds or equals a threshold value. A joint optimization algorithm of power allocation at BS and RS is considered to solve the optimization problem and to realize a mutual improvement in the performance of energy efficiency for both the primary and secondary systems. The simulation results demonstrate the validity of the analysis results and prove that the proposed transmission scheme has a higher energy efficiency than the direct transmission scheme and the transmission scheme with simultaneous wireless information and power transfer technology.

6 citations

Journal ArticleDOI
16 Jun 2023-Energies
TL;DR: In this paper , a multi-dimensional resource allocation algorithm was proposed to maximize the total system throughput in cognitive radio IoT with SWIPT by jointly optimizing time, power, and spectrum resources.
Abstract: To solve the power supply problem of battery-limited Internet of Things devices (IoDs) and the spectrum scarcity problem, simultaneous wireless information and power transfer (SWIPT) and cognitive radio (CR) technology were integrated into the Internet of Things (IoT) network to build a cognitive radio IoT (CRIoT) with SWIPT. In this network, secondary users (SUs) could adaptively switch between spectrum sensing, SWIPT, and information transmission to improve the total throughput. To solve the complicated multi-dimensional resource allocation problem in CRIoT with SWIPT, we propose a multi-dimensional resource allocation algorithm for maximizing the total throughput. Three-dimensional resources were jointly optimized, which are time resource (the duration of each process), power resource (the transmit power and the power splitting ratio of each node), and spectrum resource, under some constraints, such as maximum transmit power constraint and maximum permissible interference constraint. To solve this intractable mixed-integer nonlinear program (MINLP) problem, firstly, the sensing task assignment for cooperative spectrum sensing (CSS) was obtained by using a greedy sensing algorithm. Secondly, the original problem was transformed into a convex problem via some transformations with fixed-power splitting ratio and time switching. The Lagrange dual method and subgradient method were adopted to obtain the optimal power and channel allocation. Then, a one-dimensional search algorithm was used to obtain the optimal power splitting ratio and the time switching ratio. Finally, a heuristic algorithm was adopted to obtain the optimal sensing duration. The simulation results show that the proposed algorithm can achieve higher total system throughput than other benchmark algorithms, such as a greedy algorithm, an average algorithm, and the Kuhn–Munkres (KM) algorithm.
References
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Journal ArticleDOI
TL;DR: This paper designs the sensing duration to maximize the achievable throughput for the secondary network under the constraint that the primary users are sufficiently protected, and forms the sensing-throughput tradeoff problem mathematically, and uses energy detection sensing scheme to prove that the formulated problem indeed has one optimal sensing time which yields the highest throughput.
Abstract: In a cognitive radio network, the secondary users are allowed to utilize the frequency bands of primary users when these bands are not currently being used. To support this spectrum reuse functionality, the secondary users are required to sense the radio frequency environment, and once the primary users are found to be active, the secondary users are required to vacate the channel within a certain amount of time. Therefore, spectrum sensing is of significant importance in cognitive radio networks. There are two parameters associated with spectrum sensing: probability of detection and probability of false alarm. The higher the probability of detection, the better the primary users are protected. However, from the secondary users' perspective, the lower the probability of false alarm, the more chances the channel can be reused when it is available, thus the higher the achievable throughput for the secondary network. In this paper, we study the problem of designing the sensing duration to maximize the achievable throughput for the secondary network under the constraint that the primary users are sufficiently protected. We formulate the sensing-throughput tradeoff problem mathematically, and use energy detection sensing scheme to prove that the formulated problem indeed has one optimal sensing time which yields the highest throughput for the secondary network. Cooperative sensing using multiple mini-slots or multiple secondary users are also studied using the methodology proposed in this paper. Computer simulations have shown that for a 6 MHz channel, when the frame duration is 100 ms, and the signal-to-noise ratio of primary user at the secondary receiver is -20 dB, the optimal sensing time achieving the highest throughput while maintaining 90% detection probability is 14.2 ms. This optimal sensing time decreases when distributed spectrum sensing is applied.

2,889 citations


"Throughput Analysis of a Energy Har..." refers background in this paper

  • ...The observation statistic (TCR,i), at the i-th CRTX , can be written as [5]...

    [...]

  • ...For a large number of samples, TCR,i can be approximated to a Gaussian distribution with the mean and variance, μ0 = σ2 w, σ2 0 = 1 Ns σ4 w under H0 condition and μ1 = (1+ γs)σ w, σ2 1 = 1 Ns (1+ 2γs)σ w under H1 condition, respectively, as considered in [5]....

    [...]

  • ...where Pd,i(ts)), (Pm,i(ts)) and (Pf ,i(ts) are the individual probability of detection, probability of missed detection, probability of false alarm, respectively, over faded channel [5]....

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  • ...In [5], the authors studied the trade-off of throughput and sensing time keeping QoS of PU to a target level....

    [...]

Journal ArticleDOI
TL;DR: This paper studies a multiple-input multiple-output (MIMO) wireless broadcast system consisting of three nodes, where one receiver harvests energy and another receiver decodes information separately from the signals sent by a common transmitter, and all the transmitter and receivers may be equipped with multiple antennas.
Abstract: Wireless power transfer (WPT) is a promising new solution to provide convenient and perpetual energy supplies to wireless networks. In practice, WPT is implementable by various technologies such as inductive coupling, magnetic resonate coupling, and electromagnetic (EM) radiation, for short-/mid-/long-range applications, respectively. In this paper, we consider the EM or radio signal enabled WPT in particular. Since radio signals can carry energy as well as information at the same time, a unified study on simultaneous wireless information and power transfer (SWIPT) is pursued. Specifically, this paper studies a multiple-input multiple-output (MIMO) wireless broadcast system consisting of three nodes, where one receiver harvests energy and another receiver decodes information separately from the signals sent by a common transmitter, and all the transmitter and receivers may be equipped with multiple antennas. Two scenarios are examined, in which the information receiver and energy receiver are separated and see different MIMO channels from the transmitter, or co-located and see the identical MIMO channel from the transmitter. For the case of separated receivers, we derive the optimal transmission strategy to achieve different tradeoffs for maximal information rate versus energy transfer, which are characterized by the boundary of a so-called rate-energy (R-E) region. For the case of co-located receivers, we show an outer bound for the achievable R-E region due to the potential limitation that practical energy harvesting receivers are not yet able to decode information directly. Under this constraint, we investigate two practical designs for the co-located receiver case, namely time switching and power splitting, and characterize their achievable R-E regions in comparison to the outer bound.

2,595 citations

Proceedings ArticleDOI
05 Dec 2005
TL;DR: This paper studies spectrum-sharing between a primary licensee and a group of secondary users and suggests that collaboration may improve sensing performance significantly.
Abstract: Traditionally, frequency spectrum is licensed to users by government agencies in a fixed manner where licensee has exclusive right to access the allocated band. This policy has been de jure practice to protect systems from mutual interference for many years. However, with increasing demand for the spectrum and scarcity of vacant bands, a spectrum policy reform seems inevitable. Meanwhile, recent measurements suggest the possibility of sharing spectrum among different parties subject to interference-protection constraints. In this paper we study spectrum-sharing between a primary licensee and a group of secondary users. In order to enable access to unused licensed spectrum, a secondary user has to monitor licensed bands and opportunistically transmit whenever no primary signal is detected. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, user cannot distinguish between an unused band and a deep fade. Collaborative spectrum sensing is proposed and studied in this paper as a means to combat such effects. Our analysis and simulation results suggest that collaboration may improve sensing performance significantly

1,939 citations


"Throughput Analysis of a Energy Har..." refers background in this paper

  • ...The impact of fading on the sensing performance can be reduced significantly if the CRs in a cooperative network cooperate their decisions at the fusion centre (FC) for overall decision [1, 2]....

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  • ...The sensing performance can be influenced by fading in the sensing channel [1]....

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Posted Content
TL;DR: In this paper, the authors studied a multiple-input multiple-output (MIMO) wireless broadcast system consisting of three nodes, where one receiver harvests energy and another receiver decodes information separately from the signals sent by a common transmitter, and all the transmitter and receivers may be equipped with multiple antennas.
Abstract: Wireless power transfer (WPT) is a promising new solution to provide convenient and perpetual energy supplies to wireless networks. In practice, WPT is implementable by various technologies such as inductive coupling, magnetic resonate coupling, and electromagnetic (EM) radiation, for short-/mid-/long-range applications, respectively. In this paper, we consider the EM or radio signal enabled WPT in particular. Since radio signals can carry energy as well as information at the same time, a unified study on simultaneous wireless information and power transfer (SWIPT) is pursued. Specifically, this paper studies a multiple-input multiple-output (MIMO) wireless broadcast system consisting of three nodes, where one receiver harvests energy and another receiver decodes information separately from the signals sent by a common transmitter, and all the transmitter and receivers may be equipped with multiple antennas. Two scenarios are examined, in which the information receiver and energy receiver are separated and see different MIMO channels from the transmitter, or co-located and see the identical MIMO channel from the transmitter. For the case of separated receivers, we derive the optimal transmission strategy to achieve different tradeoffs for maximal information rate versus energy transfer, which are characterized by the boundary of a so-called rate-energy (R-E) region. For the case of co-located receivers, we show an outer bound for the achievable R-E region due to the potential limitation that practical energy harvesting receivers are not yet able to decode information directly. Under this constraint, we investigate two practical designs for the co-located receiver case, namely time switching and power splitting, and characterize their achievable R-E regions in comparison to the outer bound.

747 citations

Journal ArticleDOI
TL;DR: The optimal voting rule for any detector applied to cooperative spectrum sensing is derived and the detection threshold when energy detection is employed, and a fast spectrum sensing algorithm is proposed for a large network which requires fewer than the total number of cognitive radios while satisfying a given error bound.
Abstract: We consider cooperative spectrum sensing in which multiple cognitive radios collaboratively detect the spectrum holes through energy detection and investigate the optimality of cooperative spectrum sensing with an aim to optimize the detection performance in an efficient and implementable way. We derive the optimal voting rule for any detector applied to cooperative spectrum sensing. We also optimize the detection threshold when energy detection is employed. Finally, we propose a fast spectrum sensing algorithm for a large network which requires fewer than the total number of cognitive radios in cooperative spectrum sensing while satisfying a given error bound.

744 citations


"Throughput Analysis of a Energy Har..." refers background in this paper

  • ...It is also shown in [3] that there exists an optimal number of CRs among the cooperating CRs, for which the error in sensing performance becomes less [3]....

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