In this paper, we concentrate on a multi-relay network in which the source and the relays are equipped with limited buffers, and we study the maximum supportable arrival rates with bufferoverflow quality of service (...
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In this paper, we concentrate on a multi-relay network in which the source and the relays are equipped with limited buffers, and we study the maximum supportable arrival rates with bufferoverflow quality of service (QoS) guaranteed at all buffered nodes. To this end, the effective capacity (EC) function of such a network is derived as a function of individual QoS exponents of the source and relays denoted by theta(S), theta(R1), ... , theta(RN). To reduce the computational complexity, a closed form expression for the EC is computed. Then, a time slot allocation algorithm is proposed based on the defined EC function. To show the results, both scenarios of heterogeneous and homogeneous queuing at the relays are investigated. The behavior of derived EC and the proposed algorithm are evaluated by some numerical results. It is shown for theta(S) > theta(R), EC remains constant versus theta(R) and varies versus theta(S) and vice versa, meaning that among theta(S) and theta(R), the higher one is determinative in the amount of E-C(theta(S), theta(R)). Also, it is found that the majority of resources is allocated to the node with a more stringent QoS constraint.
In this paper, we characterize the optimal strategies focusing on the throughput and the system energy efficiency of wireless-powered communication networks (WPCNs) in the presence of delay-limited sources. Each energ...
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In this paper, we characterize the optimal strategies focusing on the throughput and the system energy efficiency of wireless-powered communication networks (WPCNs) in the presence of delay-limited sources. Each energy-harvesting user equipment is assumed to be subject to limitations on the buffer overflow probability, specified by the quality of service (QoS) exponent theta. Correspondingly, the time allocation strategies for downlink energy harvesting and uplink information transfer depend on these QoS constraints, potentially overriding the doubly near-far problem of WPCNs. We consider the non-orthogonal transmission and time-division multiple access protocols for the uplink information transfer of WPCN, and for both cases, we formulate energy efficiency and throughput maximizing problems to obtain the globally optimal solution that satisfy the statistical QoS constraints. Since these optimization problems fall into concave or pseudo-concave categories, Karush-Kuhn-Tucker conditions are necessary and sufficient for global optimality, using which we obtain analytical expressions for the optimal operating intervals. In addition, in several cases, due to difficulty in providing closed-form expressions, we develop algorithms to solve the problems numerically. Finally, we provide the simulation results to confirm and further analyze the theoretical characterizations. We mainly observe that QoS constraints primarily affect the optimal time allocation policies as well as achievable rate distribution among the users, enabling us to overcome the doubly near-far problem of energy-harvesting communications networks pointed out as one of the critical issues in the literature.
This study investigates the performance of practical wireless exclusive OR (XOR) two-way relay (TWR) system, in which finite buffer, lossy wireless channels and non-negligible signalling overhead are considered. Speci...
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This study investigates the performance of practical wireless exclusive OR (XOR) two-way relay (TWR) system, in which finite buffer, lossy wireless channels and non-negligible signalling overhead are considered. Specifically, the authors develop a new analytical model to explicitly characterise the transmissions of both the end-nodes and the relay. The impact of scheduling on the throughput, queuing delay, power consumption and buffer overflow probability of XOR-TWR is evaluated. Validated by simulations, the model can precisely quantify the performance of XOR-TWR and adequately allocate the relay's buffer adapting to the wireless link qualities and signalling overhead.
In this paper, we study the performance of wireless information and power transfer in the presence of statistical queuing constraints. We consider harvest-then-transmit protocol in which users first harvest energy fro...
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ISBN:
(纸本)9781479966646
In this paper, we study the performance of wireless information and power transfer in the presence of statistical queuing constraints. We consider harvest-then-transmit protocol in which users first harvest energy from a dedicated source and then transmit information through an uplink multiple access channel (MAC). Each user is subject to limitations on the buffer overflow probability, specified by the quality of service (QoS) exponent., and the optimal time allocation for energy harvesting and information decoding operations depends on these constraints in addition to the channel characteristics. We formulate optimization problems to maximize the throughput with and without QoS constraints. In both cases, the problems are convex, and hence Karush-KuhnTucker (KKT) conditions are necessary and sufficient for global optimality. However, it is difficult to obtain closed-form expressions for optimal time interval since we assume that operating intervals are independent of each fading state realization. Hence, we develop an algorithm to obtain optimal solutions numerically. Simulation results justify that QoS constraints primarily affect achievable rate distribution among the users, and override the channel conditions.
In this paper, we study the performance of energy harvesting communication networks focusing on the system energy efficiency. We consider multiple wireless-powered users that harvest energy from a wireless power sourc...
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ISBN:
(纸本)9781509024827
In this paper, we study the performance of energy harvesting communication networks focusing on the system energy efficiency. We consider multiple wireless-powered users that harvest energy from a wireless power source (WPS) and then transmit information uplink through time-division multiple access channels to the access point (AP). Besides, users can also scavenge energy from an information-bearing signal transmitted by a user scheduled for uplink data transfer. Each user is subject to limitations on the buffer overflow probability, specified by the quality of service (QoS) exponent theta. The optimal time allocation strategies, i.e., energy harvesting and data transmission intervals, are affected by such QoS constraints in addition to the channel characteristics. Thus, we formulate optimization problems to maximize the system energy efficiency (measured by the sum effective capacity per total consumed energy) while taking statistical queuing constraints into account. In addition, we provide details for the optimal time allocation strategies in the absence of these constraints. Since the problems, in both cases, are pseudo-concave, Karush-Kuhn-Tucker (KKT) conditions guarantee global optimality. However, it is difficult to obtain closed-form expressions for the optimal solution. Hence, we employ the Dinkelbach's method to solve the problems using standard numerical tools. Simulation results demonstrate that QoS constraints are critical, dictating time allocation, and correspondingly rate distribution, among the wireless-powered users in the presence of delay-sensitive sources.
The quality of service (QoS) performance analysis is of great guiding significance for a QoS guarantee of secondary users (SUs). However, the QoS performance of SUs has not been well studied, especially how it is impa...
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The quality of service (QoS) performance analysis is of great guiding significance for a QoS guarantee of secondary users (SUs). However, the QoS performance of SUs has not been well studied, especially how it is impacted by the traffic property of primary users (PUs). In this study, the authors propose a method to analyse the queue performance of the SU when the active and inactive durations of PUs follow general distributions. To characterise the non-memoryless property of the channel when the distributions of PUs active/inactive durations are general distributions, they propose a two-dimensional Markov chain to model the states of the channel. By using this Markov chain, they derive the effective capacity (EC) function of the cognitive radio network. On the basis of the EC function and the effective bandwidth function, the queue performance of the SU, that is, the stationary tail distribution of the queue length, is estimated. The author's result can not only be used to calculate other QoS metrics, such as the buffer overflow probability and throughput, but also provide some guidelines for QoS guarantee of the SU. Finally, they verify their work by comparing the analytical results with simulation results.
In this paper, we study the performance of wireless information and power transfer in the presence of statistical queuing constraints. We consider harvest-then-transmit protocol in which users first harvest energy fro...
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ISBN:
(纸本)9781479966653
In this paper, we study the performance of wireless information and power transfer in the presence of statistical queuing constraints. We consider harvest-then-transmit protocol in which users first harvest energy from a dedicated source and then transmit information through an uplink multiple access channel (MAC). Each user is subject to limitations on the buffer overflow probability, specified by the quality of service (QoS) exponent θ, and the optimal time allocation for energy harvesting and information decoding operations depends on these constraints in addition to the channel characteristics. We formulate optimization problems to maximize the throughput with and without QoS constraints. In both cases, the problems are convex, and hence Karush-Kuhn-Tucker (KKT) conditions are necessary and sufficient for global optimality. However, it is difficult to obtain closed-form expressions for optimal time interval since we assume that operating intervals are independent of each fading state realization. Hence, we develop an algorithm to obtain optimal solutions numerically. Simulation results justify that QoS constraints primarily affect achievable rate distribution among the users, and override the channel conditions.
In this paper, we study the performance of energy harvesting communication networks focusing on the system energy efficiency. We consider multiple wireless-powered users that harvest energy from a wireless power sourc...
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ISBN:
(纸本)9781509024834
In this paper, we study the performance of energy harvesting communication networks focusing on the system energy efficiency. We consider multiple wireless-powered users that harvest energy from a wireless power source (WPS) and then transmit information uplink through time-division multiple access channels to the access point (AP). Besides, users can also scavenge energy from an information-bearing signal transmitted by a user scheduled for uplink data transfer. Each user is subject to limitations on the buffer overflow probability, specified by the quality of service (QoS) exponent θ. The optimal time allocation strategies, i.e., energy harvesting and data transmission intervals, are affected by such QoS constraints in addition to the channel characteristics. Thus, we formulate optimization problems to maximize the system energy efficiency (measured by the sum effective capacity per total consumed energy) while taking statistical queuing constraints into account. In addition, we provide details for the optimal time allocation strategies in the absence of these constraints. Since the problems, in both cases, are pseudo-concave, Karush-KuhnTucker (KKT) conditions guarantee global optimality. However, it is difficult to obtain closed-form expressions for the optimal solution. Hence, we employ the Dinkelbach's method to solve the problems using standard numerical tools. Simulation results demonstrate that QoS constraints are critical, dictating time allocation, and correspondingly rate distribution, among the wirelesspowered users in the presence of delay-sensitive sources.
The frame generation process, used as the first stage of the two-stage multiplexing mechanism of the advanced orbiting system (AOS), affects the transmission efficiency and time delay characteristic in performance. Ho...
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ISBN:
(纸本)9781467374415
The frame generation process, used as the first stage of the two-stage multiplexing mechanism of the advanced orbiting system (AOS), affects the transmission efficiency and time delay characteristic in performance. However, in the existing study related to the frame generation technology, the satellite-borne buffer size limits the eleven main issues, this article performs performance analysis on periodic frame generation algorithm in AOS on this basis, deriving the computational formula of buffer overflow probability and the mean value of multiplexing efficiency of packet, performing the simulation experiment and verifying the correctness of theoretical derivation. Its result can provide guidance for engineering design.
The frame generation process, used as the first stage of the two-stage multiplexing mechanism of the advanced orbiting system（AOS）, affects the transmission efficiency and time delay characteristic in performance. H...
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The frame generation process, used as the first stage of the two-stage multiplexing mechanism of the advanced orbiting system（AOS）, affects the transmission efficiency and time delay characteristic in performance. However, in the existing study related to the frame generation technology, the satellite-borne buffer size limits the eleven main issues, this article performs performance analysis on periodic frame generation algorithm in AOS on this basis, deriving the computational formula of buffer overflow probability and the mean value of multiplexing efficiency of packet, performing the simulation experiment and verifying the correctness of theoretical derivation. Its result can provide guidance for engineering design.
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