scholarly journals Joint Power and Time Allocation in Full-Duplex Wireless Powered Communication Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Yongbo Cheng ◽  
Pengcheng Fu ◽  
Yuchao Chang ◽  
Baoqing Li ◽  
Xiaobing Yuan
Keyword(s):  
Energy Consumption ◽  
Communication Networks ◽  
Time Allocation ◽  
Access Point ◽  
Optimization Techniques ◽  
Full Duplex ◽  
Proportional Fairness ◽  
Joint Power ◽  
High Data ◽  
Fair Scheduler

We consider a full-duplex wireless powered communication network (WPCN) with one hybrid access point (H-AP) and a set of distributed users, where downlink wireless energy broadcasting is employed at H-AP and at the same time, uplink wireless information transmission takes place at users in a time-division multiple access manner. We extend proportional fair scheduler to this category of network when dealing with "doubly near-far problem," where users far away from H-AP achieve low throughput but suffer from both low harvested energy and high data transmission power consumption. We jointly optimize power and time allocation for each user to achieve proportional fairness while controlling the energy consumption offset for network to a low level. By using optimization techniques, the optimal transmit power and transmission time for users are obtained via proposed algorithm. Simulation results confirm the positive effect on improving the fairness metric and reducing energy consumption offset for network.

scholarly journals Fairness-Aware Resource Allocation in Full-Duplex Backscatter-Assisted Wireless Powered Communication Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Rui Jiang ◽  
Meihua Liu ◽  
Xiaoming Wang ◽  
Youyun Xu
Keyword(s):  
Energy Harvesting ◽  
Communication Networks ◽  
Time Allocation ◽  
Path Loss ◽  
Access Point ◽  
Optimization Techniques ◽  
Full Duplex ◽  
Optimal Time ◽  
Backscatter Communication ◽  
Time Division

In this paper, we introduce a full-duplex backscatter-assisted wireless powered communication network (FDBA-WPCN) with a full-duplex access point (FAP) and multiple energy harvesting wireless devices (WDs). The communication mode is a combination of backscatter communication (BC) and harvest-then-transmit (HTT). The entire time period of network is divided into energy harvesting/backscattering (EHB) period and information transmission (IT) period. In the EHB period, each WD either reflects information to the FAP by backscatter or harvests energy to prepare for the IT period. In the IT period, the WDs use their harvested energy to transmit information to FAP in time division multiple access (TDMA). However, under the setting, WDs with different distances from FAP will encounter unfairness in throughput due to the round-trip path loss in backscatter and the doubly near-far problem in HTT. To overcome the drawback, an optimization problem is considered to maximize the sum throughput under the condition of ensuring throughput fairness. By using convex optimization techniques, we obtain the optimal time allocation and the maximum same throughput of each WD. Comparing to the other two benchmark schemes, the simulation results prove the superiority of our proposed method.

Robust Beamforming and Time Allocation for Full-Duplex Wireless-Powered Communication Networks

2019 ◽  
Vol 23 (9) ◽  
pp. 1665-1669
Author(s):  
Jai-Hoon Lee ◽  
Yong-Ho Cho ◽  
Dong-Jo Park ◽  
Dong Eui Chang
Keyword(s):  
Communication Networks ◽  
Time Allocation ◽  
Full Duplex ◽  
Robust Beamforming

scholarly journals Wireless Powered Mobile Edge Computing Systems: Simultaneous Time Allocation and Offloading Policies

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 965
Author(s):  
Amna Irshad ◽  
Ziaul Haq Abbas ◽  
Zaiwar Ali ◽  
Ghulam Abbas ◽  
Thar Baker ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Time Allocation ◽  
Minimum Cost ◽  
Access Point ◽  
Edge Computing ◽  
Mobile Edge Computing ◽  
Computational Power ◽  
Local Computation ◽  
Computing Systems ◽  
Battery Capacity

To improve the computational power and limited battery capacity of mobile devices (MDs), wireless powered mobile edge computing (MEC) systems are gaining much importance. In this paper, we consider a wireless powered MEC system composed of one MD and a hybrid access point (HAP) attached to MEC. Our objective is to achieve a joint time allocation and offloading policy simultaneously. We propose a cost function that considers both the energy consumption and the time delay of an MD. The proposed algorithm, joint time allocation and offload policy (JTAOP), is used to train a neural network for reducing the complexity of our algorithm that depends on the resolution of time and the number of components in a task. The numerical results are compared with three benchmark schemes, namely, total local computation, total offloading and partial offloading. Simulations show that the proposed algorithm performs better in producing the minimum cost and energy consumption as compared to the considered benchmark schemes.

scholarly journals Time Allocation and Optimization in Time-Reversal Wireless Powered Communication Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Fangwei Li ◽  
Yue Wu ◽  
Yifang Nie ◽  
Ce Shi
Keyword(s):  
Convex Optimization ◽  
Communication Networks ◽  
Time Reversal ◽  
Time Allocation ◽  
Optimization Problem ◽  
Access Point ◽  
Convex Optimization Problem ◽  
Space Division Multiple Access ◽  
Optimal Resource ◽  
Special Space

This paper studies optimal resource allocation in the wireless powered communication networks (WPCN) combined with time reversal (TR) in which one hybrid access point (H-AP) broadcasts constant wireless energy to a set of distributed users in the downlink (DL) and receives information from the users via space division multiple access (SDMA) in the uplink (UL). Inevitable interferences will occur when users transmit information in the UL simultaneously and the special space-time focusing of TR is used to suppress the interferences. An efficient protocol is proposed to support wireless energy transfer (WET) and TR in the DL and wireless information transmission in the UL for the proposed TR-WPCN. We optimize the time allocations to the H-AP for DL WET, DL TR, and UL WIT to maximize the sum throughput. Due to the nonconvexity of the studied optimization problem, we optimize variables successively, where the nonconvex optimization problem is transformed into the convex optimization problem. The approximate convex optimization problem can then be solved iteratively combined with the dichotomy method. Simulation results show that the proposed scheme can effectively suppress interferences and improve system performance.

scholarly journals Data Downloading on the Sparse Coverage-Based Wireless Networks

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Helal Chowdhury ◽  
Janne Lehtomäki ◽  
Juha-Pekka Mäkelä ◽  
Sastri Kota
Keyword(s):  
Wireless Networks ◽  
Wireless Communication ◽  
Communication Networks ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Access Point ◽  
Wireless Communication Networks ◽  
High Data ◽  
Distance Relationship ◽  
The Impact

Infostation, hotspot, and drive-thru internet are examples of sparse coverage-based wireless networks. These wireless communication networks provide low-cost, delay insensitive high data rate services intermittently with discontinuous coverage. Radio propagation parameters, velocity of the user, distance between the user, and access point are the key factors that affect the throughput and the amount of information downloaded from such sparse coverage-based wireless networks. To evaluate the performance of such wireless communication networks analytically the impact of above mentioned factors can be modeled with simplified relationship model such as received signal strength versus distance or signal to noise ratio versus throughput. In the paper, we exploit the relationship between throughput and distance and develop two throughput distance relationship models to evaluate the performance of multirate wireless networks. These two throughput distance relationship models are used in calculation of average throughput as well as downloaded file size. Numerical values are presented for the IEEE 802.11n standard. The numerical results verify that the new proposed technique can be used as an alternative to the simulations to evaluate the performance of sparse coverage-based wireless networks.

scholarly journals Optimal Energy Beamforming to Minimize Transmit Power in a Multi-Antenna Wireless Powered Communication Network

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 509
Author(s):  
Iqra Hameed ◽  
Pham-Viet Tuan ◽  
Mario R. Camana ◽  
Insoo Koo
Keyword(s):  
Communication Network ◽  
Minimization Problem ◽  
Time Allocation ◽  
Access Point ◽  
Power Minimization ◽  
Transmit Power ◽  
Optimal Energy ◽  
Single Antenna ◽  
Information Signal ◽  
Energy Beamforming

In this paper, we study the transmit power minimization problem with optimal energy beamforming in a multi-antenna wireless powered communication network (WPCN). The considered network consists of one hybrid access point (H-AP) with multiple antennae and multiple users with a single antenna each. The H-AP broadcasts an energy signal on the downlink, using energy beamforming to enhance the efficiency of the transmit energy. In this paper, we jointly optimize the downlink time allocation for wireless energy transfer (WET), the uplink time allocation for each user to send a wireless information signal to the H-AP, the power allocation to each user on the uplink, and the downlink energy beamforming vectors while controlling the transmit power at the H-AP. It is challenging to solve this non-convex complex optimization problem because it is numerically intractable and involves high computational complexity. We exploit a sequential parametric convex approximation (SPCA)-based iterative method, and propose optimal and sub-optimal solutions for the transmit power minimization problem. All the proposed schemes are verified by numerical simulations. Through the simulation results, we present the performance of the proposed schemes based on the effect of the number of transmit antennae and the number of users in the proposed WPCN. Through the performance evaluation, we show that the SPCA-based joint optimization solution performance is superior to other solutions.

Lightbeam Configuration Method and Interference Elimination Resource Scheduling for Indoor Multibeam VLC Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Cong-Nam Tran ◽  
Nam-Hoang Nguyen ◽  
Trong-Minh Hoang
Keyword(s):  
Transmission Rate ◽  
Resource Scheduling ◽  
Packet Delay ◽  
Access Point ◽  
Visible Light Communications ◽  
Resource Allocation Algorithm ◽  
Downlink Transmission ◽  
High Data ◽  
Interference Elimination ◽  
Multi Access

AbstractVisible light communications (VLC) is considered as an alternative communications technology for providing indoor wireless services. VLC systems are expected to offer high data transmission rate and seamless coverage. In order to achieve these requirements, VLC systems utilizing multi-lightbeam access points (multibeam VLC-AP) for downlink transmission have been proposed recently. In this paper, we present a lightbeam configuration method and an interference elimination resource scheduling mechanism (IERS) for indoor multibeam multi-access point VLC systems. The proposed lightbeam configuration method ensures seamless connectivity between user equipment and VLC-AP. The proposed IERS mechanism consists of a beam assignment algorithm and a resource allocation algorithm for eliminating co-channel interference as well as improving system performance. Performance results obtained by computer simulation indicate that there are significant improvements in terms of downlink signal to interference plus noise ratio, user throughput and packet delay when the proposed IERS mechanism is deployed.

Mobility aware of WDM-based CMO OFDM communication system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saad M. Hardan ◽  
Ayad A. Abdulkafi ◽  
Saadi Hamad Thalij ◽  
Sherine S. Jumaah
Keyword(s):  
Wavelength Division Multiplexing ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Light Emitting Diode ◽  
Access Point ◽  
Mobile Users ◽  
Visible Light Communications ◽  
Optical Wireless Communications ◽  
High Data ◽  
The Impact

Abstract The continued increase in several mobile applications forces to replace existing limited spectrum indoor radio frequency wireless connections with high-speed ones. Visible light communications (VLC) technology has gained prominence in the development of high data rate transmission for fifth-generation networks. In optical wireless communications, light-emitting diode (LED) transmitters are used in applications that desire mobility as LED divergence enables larger coverage. Since each VLC access point covers a small area, handovers of mobile users are inevitable. Wavelength division multiplexing (WDM) can be used in VLC systems to tackle the above issue and to meet the increasing demand for indoor connectivity with high bit rates. In this paper, a new system architecture for WDM with coded modulated optical in orthogonal frequency division multiplexing (OFDM) VLC system in conjunction with red, green, blue, and yellow (RGBY) LEDs is proposed to reduce the impact of random receiver orientation of indoor mobile users over VLC downlink channels and improves the system’s bit-error-rate (BER) performance. Simulation results show that the proposed method is not affected by the user’s mobility and hence it performs better than other approaches, in terms of BER for all scenarios and at all positions. This study reveals that using WDM-OFDM-VLC with RGBY LEDs to construct a VLC system is very promising.

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