Browsing by Author "Coleri, Sinem"

Now showing 1 - 9 of 9

Citation - WoS: 9
Citation - Scopus: 10
Energy Efficient Robust Scheduling of Periodic Sensor Packets for Discrete Rate Based Wireless Networked Control Systems
(Elsevier, 2020) Farayev, Bakhtiyar; Şadi, Yalçın; Uçar, Seyhan; Şadi, Yalçın; Coleri, Sinem
Wireless networked control systems (WNCSs) require the design of a robust scheduling algorithm that meets the stringent timing and reliability requirements of control systems, despite the limited battery resources of sensor nodes and adverse properties of wireless communication for delay and packet errors. In this article, we propose a robust delay and energy constrained scheduling algorithm based on the exploitation of the mostly pre-known periodic data generation nature of sensor nodes in control systems. We first formulate the joint optimization of scheduling, power control and rate adaptation for discrete rate transmission model, in which only a finite set of transmission rates are supported, as a Mixed-Integer Non-linear Programming problem and prove its NP-hardness. Next, we propose an optimal polynomial-time power control and rate adaptation algorithm for minimizing the transmission time of a node subset. We then design a novel polynomial-time heuristic scheduling algorithm based on first determining the concurrently transmitting node subsets and then distributing them uniformly over time by a modified Karmarkar-Karp algorithm. We demonstrate the superior performance of the proposed scheduling algorithm in terms of robustness, delay and runtime on the Low-Rate Wireless Personal Area Network (LR-WPAN) simulation platform, which we developed in network simulator-3 (ns3).
Citation - WoS: 9
Citation - Scopus: 10
Minimum Length Scheduling for Discrete-Rate Full-Duplex Wireless Powered Communication Networks
(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Şadi, Yalçın; Sadi, Yalcin; Coleri, Sinem
Wireless powered communication networks (WPCNs) will act as a major enabler of massive machine type communications (MTCs), which is a major service domain for 5G and beyond systems. The MTC networks will be deployed by using low-power transceivers with finite discrete configurations. This paper considers minimum length scheduling problem for full-duplex WPCNs, where users transmit information to a hybrid access point at a rate chosen from a finite set of discrete-rate levels. The optimization problem considers energy causality, data and maximum transmit power constraints, and is proven to be NP-hard. As a solution strategy, we define the minimum length scheduling (MLS) slot, which is slot of minimum transmission completion time while starting transmission at anytime after the decision time. We solve the problem optimally for a given transmission order based on the optimality analysis of MLS slot. For the general problem, we categorize the problem based on whether the MLS slots of users overlap over time. We propose optimal algorithm for non-overlapping scenario by allocating the MLS slots, and a polynomial-time heuristic algorithm for overlapping scenario by allocating the transmission slot to the user with earliest MLS slot. Through simulations, we demonstrate significant gains of scheduling and discrete rate allocation.
Citation - WoS: 17
Citation - Scopus: 22
Minimum Length Scheduling for Full Duplex Time-Critical Wireless Powered Communication Networks
(IEEE, 2020) Şadi, Yalçın; Şadi, Yalçın; Coleri, Sinem
Radio frequency (RF) energy harvesting is key in attaining perpetual lifetime for time-critical wireless powered communication networks (WPCNs) due to full control on energy transfer, far field region, small and low-cost circuitry. In this paper, we propose a novel minimum length scheduling problem to determine the optimal power control, time allocation and schedule subject to data, energy causality and maximum transmit power constraints in a full-duplex WPCN. We first formulate the problem as a mixed integer non-linear programming problem and conjecture that the problem is NP-hard. As a solution strategy, we demonstrate that the power control and time allocation, and the scheduling problems can be solved separately in the optimal solution. For the power control and time allocation problem, we derive the optimal solution by evaluating Karush-Kuhn-Tucker conditions. For the scheduling, we introduce a penalty function allowing reformulation of the problem as a sum penalty minimization problem. Upon derivation of the optimality conditions based on the characteristics of the penalty function, we propose two polynomial-time heuristic algorithms and a reduced-complexity exact algorithm employing smart pruning techniques. Via extensive simulations, we illustrate that the proposed heuristic schemes outperform the schemes for predetermined transmission order of users and achieve close-to-optimal solutions.
Citation - WoS: 4
Citation - Scopus: 4
Minimum Length Scheduling for Multi-Cell Full Duplex Wireless Powered Communication Networks
(Mdpi, 2021) Iqbal, Muhammad Shahid; Şadi, Yalçın; Sadi, Yalcin; Coleri, Sinem
Wireless powered communication networks (WPCNs) will be a major enabler of massive machine type communications (MTCs), which is a major service domain for 5G and beyond systems. These MTC networks will be deployed by using low-power transceivers and a very limited set of transmission configurations. We investigate a novel minimum length scheduling problem for multi-cell full-duplex wireless powered communication networks to determine the optimal power control and scheduling for constant rate transmission model. The formulated optimization problem is combinatorial in nature and, thus, difficult to solve for the global optimum. As a solution strategy, first, we decompose the problem into the power control problem (PCP) and scheduling problem. For the PCP, we propose the optimal polynomial time algorithm based on the evaluation of Perron-Frobenius conditions. For the scheduling problem, we propose a heuristic algorithm that aims to maximize the number of concurrently transmitting users by maximizing the allowable interference on each user without violating the signal-to-noise-ratio (SNR) requirements. Through extensive simulations, we demonstrate a 50% reduction in the schedule length by using the proposed algorithm in comparison to unscheduled concurrent transmissions.
Citation - WoS: 1
Citation - Scopus: 5
Optimal On-Off Transmission Schemes for Full Duplex Wireless Powered Communication Networks
(IEEE, 2020) Iqbal, Muhammad Shahid; Şadi, Yalçın; Şadi, Yalçın; Coleri, Sinem
In this paper, we consider a full duplex wireless powered communication network where multiple users with radio frequency energy harvesting capability communicate to an energy broadcasting hybrid access point. We investigate the minimum length scheduling and sum throughput maximization problems considering on-off transmission scheme in which users either transmit at a constant power or remain silent. For minimum length scheduling problem, we propose a polynomial-time optimal scheduling algorithm. For sum throughput maximization, we first derive the characteristics of an optimal schedule and then to avoid intractable complexity. We propose a polynomial-time heuristic algorithm which is illustrated to perform nearly optimal through numerical analysis.
Citation - WoS: 0
Citation - Scopus: 0
Resource Allocation for Discrete Rate Multi-Cell Energy Constrained Communication Networks
(Springer, 2024) Şadi, Yalçın; Salik, Elif Dilek; Sadi, Yalcin; Coleri, Sinem
Radio frequency energy harvesting is a promising technique to extend the lifetime of wireless powered communication networks (WPCNs) due to its controllability. In this paper, we consider a novel discrete rate based multi-cell WPCN, where multiple hybrid access points (HAPs) transmit energy to the users and users harvest this energy for the information transmission by using a transmission rate selected from a finite set of discrete rate levels. We formulate an optimization problem to minimize the schedule length through optimal rate allocation and scheduling of the users while considering the traffic demand, energy causality and interference constraints. The problem is mixed integer non-linear programming problem. Initially, we investigate the problem for non-simultaneous and simultaneous transmission considering both predetermined and variable transmission rates. We propose optimal and heuristic algorithms for all these categories by using optimality analysis, Perron-Frobenius conditions and iterative improvement of the total schedule length. Then, for the general problem, we propose heuristic algorithm based on the maximization of the number of concurrently transmitting users within each time slot by considering the maximum allowed interference level of the users. Via extensive simulations, we demonstrate significant improvement in schedule length through rate selection and proper scheduling of concurrently transmitting users.
Citation - WoS: 0
Citation - Scopus: 0
Resource Allocation for Multi-Cell Full-Duplex Wireless Powered Communication Networks
(Springer, 2024) Şadi, Yalçın; Sadi, Yalcin; Kazmi, Syed Adil Abbas; Coleri, Sinem
Wireless powered communication networks (WPCNs) are crucial in achieving perpetual lifetime for the machine-type communication (MTC) and Internet of things (IoT) in fifth-generation (5G) communication and beyond networks. Practical WPCNs cover a broad region and have a significant number of sensors, requiring multi-cell deployment. We investigate the minimum length scheduling problem for a multi-cell full-duplex WPCNs to find the optimal power and schedule by considering the simultaneous transmission, maximum transmit power and energy causality constraints for the users. The optimization problem to minimize the schedule length is combinatorial, thus, difficult to find the global optimum solution. To overcome this, we divide the problem into two subproblems, i.e., power control problem (PCP) and the scheduling problem. Then, we present the optimal polynomial time algorithm for the PCP based on the use of the bisection method and evaluation of the Perron-Frobenius criteria. Then, by using the PCP solution, we calculate the optimal transmission time for the users that are scheduled by the scheduling algorithm. For the scheduling problem, we define a penalty function that represents the gain of simultaneous transmission over the individual transmission of the users and we show that the minimization of schedule length is similar to the minimization of sum of penalties. Following the optimum analysis of the proposed penalty metric, we present a heuristic algorithm that tries to minimize the sum penalties of the simultaneously transmitting users over the schedule. Through extensive simulations, we show significant gains of scheduling for concurrent transmissions over individual transmissions.
Citation - Scopus: 3
Scheduling and Relay Selection for Full-Duplex Wireless Powered Cooperative Communication Networks
(Institute of Electrical and Electronics Engineers Inc., 2020) Iqbal, Muhammad Shahid; Şadi, Yalçın; Syed, Kazmi Abbas Adil; Coleri, Sinem; Sadi, Yalçın
In this manuscript, we consider a full-duplex wireless powered cooperative communication system where the users communicate with a hybrid access point through relays. We formulate an optimization problem with the objective to minimize the total transmission time through user scheduling and relay selection while considering the traffic demand, energy causality and initial battery levels of the users. The formulated optimization problem is a mixed integer non-linear programming problem, hence difficult to solve for the global optimal solution. As a solution strategy, we decompose the problem into sub problems: time allocation, scheduling and relay selection. In the time allocation problem; the schedule and relays are assumed to be pre-known, we derive the optimal solution by using the optimality analysis. For the scheduling problem; we assume that users know their relays, we determine the optimal schedule. For the relay selection problem; users transmit their information in a pre-determined order, we determine the optimal relays for each user. For the overall scheduling and relay selection problem, we propose a heuristic algorithm which iteratively determines the scheduling and relay selection in polynomial time by using the optimal solutions of the individual relay selection and scheduling problems. Through simulations, we demonstrate that the scheduling length can be significantly reduced through proper scheduling and relay selection. The proposed algorithm performs very close to the optimal solution for different maximum user transmit power, network densities, initial battery levels and hybrid access point power levels. © 2020 IEEE.
Citation - WoS: 10
Citation - Scopus: 2
Throughput Maximization in Discrete Rate Based Full Duplex Wireless Powered Communication Networks
(John Wıley & Sons Ltd, 2020) Iqbal, Muhammad Shahid; Şadi, Yalçın; Şadi, Yalçın; Coleri, Sinem
In this study, we consider a discrete rate full-duplex wireless powered communication network. We characterize a novel optimization framework for sum throughput maximization to determine the rate adaptation and transmission schedule subject to energy causality and user transmit power. We first formulate the problem as a mixed integer nonlinear programming problem, which is hard to solve for a global optimum in polynomial-time. Then, we investigate the characteristics of the solution and propose a polynomial time heuristic algorithm for rate adaptation and scheduling problem. Through numerical analysis, we illustrate that the proposed scheduling algorithm outperforms the conventional schemes such as equal time allocation half-duplex and on-off transmission schemes for different initial battery levels, hybrid access point transmit power and network densities.