scholarly journals Efficient Placement of an Aerial Relay Drone for Throughput Maximization

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hazim Shakhatreh ◽  
Ali Alenezi ◽  
Ahmad Sawalmeh ◽  
Muhannad Almutiry ◽  
Waed Malkawi
Keyword(s):  
Power Allocation ◽  
Path Loss ◽  
Relay Node ◽  
Base Station ◽  
Wireless Devices ◽  
User Coverage ◽  
Water Filling ◽  
Sum Rate ◽  
Equal Power Allocation ◽  
Equal Power

Unmanned aerial vehicle (UAV) communication can be used in overcrowded areas and either during or postdisaster situations as an evolving technology to provide ubiquitous connections for wireless devices due to its flexibility, mobility, and good condition of the line of sight channels. In this paper, a single UAV is used as an aerial relay node to provide connectivity to wireless devices because of the considerable distance between wireless devices and the ground base station. Specifically, two path loss models have been utilized; a cellular-to-UAV path loss for a backhaul connection and an air-to-ground path loss model for a downlink connection scenario. Then, the tradeoff introduced by these models is discussed. The problem of efficient placement of an aerial relay node is formulated as an optimization problem, where the objective is to maximize the total throughput of wireless devices. To find an appropriate location for a relay aerial node that maximizes the overall throughput, we first use the particle swarm optimization algorithm to find the drone location; then, we use three different approaches, namely, (1) the equal power allocation approach, (2) water filling approach, and (3) modified water filling approach to maximize the total users’ throughput. The results show that the modified water filling outperforms the other two approaches in terms of the average sum rate of all users and the total number of served users. More specifically, in the best-case scenario, it was observed that the average sum rate of the modified water filling is better than the equal power allocation and ensuring 100% coverage. In contrast, the water filling provides a very close average sum rate to the modified water filling, but it only provides a 28% user coverage.

scholarly journals Performance of Equal Power Allocation in Multiuser OFDM-Based Cognitive Radio Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Yonghong Zhang ◽  
Cyril Leung
Keyword(s):  
Cognitive Radio ◽  
Power Allocation ◽  
Activity Levels ◽  
Cognitive Radio Systems ◽  
Water Filling ◽  
Radio Systems ◽  
Cr System ◽  
Equal Power Allocation ◽  
Equal Power ◽  
Multiuser Ofdm

The performance difference between a simple equal subchannel power allocation and the optimal water-filling subchannel power allocation schemes is studied for a multiuser OFDM-based cognitive radio (CR) system. It is shown that this difference depends on the average subchannel gain variations among the CR users as well as the activity levels of the primary users.

scholarly journals Energy-Efficient Dual-Iteration Power Allocation for Two-Phase Relay System with Massive Antennas

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Long Zhao ◽  
Wei Xiang ◽  
Jie Mei ◽  
Hui Zhao ◽  
Hang Long ◽  
...  
Keyword(s):  
Power Allocation ◽  
Relay Node ◽  
Spectrum Efficiency ◽  
Amplify And Forward ◽  
Zero Forcing ◽  
Channel State ◽  
Relay System ◽  
Two Phase ◽  
Massive Antennas ◽  
Equal Power Allocation

This paper considers the scenario where multiple source nodes communicate with multiple destination nodes simultaneously with the aid of an amplify-and-forward relay equipped with massive antennas. In order to achieve optimal energy efficiency (EE) of the entire relay system, this paper investigates the power allocation problem for the multiple pairs of nodes at both the source nodes and the relay node, where the relay employs the backward and forward zero-forcing filters. Since the EE optimization problem cannot be solved analytically, we propose a two-phase power allocation method. Given power allocation of one phase, the optimal power allocation is derived for the other phase. Furthermore, two dual-iteration power allocation (DIPA) algorithms with performance approaching that of optimal EE are developed based on the instantaneous and statistic channel state information, respectively. Numerical results show that the proposed DIPA algorithms can greatly improve EE while guaranteeing spectrum efficiency (SE) when compared with the equal power allocation algorithm. Moreover, both algorithms suggest that deploying a rational number of antennas at the relay node and multiplexing a reasonable number of node pairs can improve on the EE and SE.

scholarly journals Improved Water-Filling Power Allocation for Energy-Efficient Massive MIMO Downlink Transmissions

2017 ◽  
Vol 63 (1) ◽  
pp. 79-84
Author(s):  
M. K Noor Shahida ◽  
Rosdiadee Nordin ◽  
Mahamod Ismail
Keyword(s):  
Power Allocation ◽  
Network Architecture ◽  
Massive Mimo ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Downlink Transmission ◽  
Allocation Algorithm ◽  
Mimo Antenna ◽  
Water Filling ◽  
Water Filling Algorithm

Abstract Energy Efficiency (EE) is becoming increasingly important for wireless communications and has caught more attention due to steadily rising energy costs and environmental concerns. Recently, a new network architecture known as Massive Multiple-Input Multiple-Output (MIMO) has been proposed with the remarkable potential to achieve huge gains in EE with simple linear processing. In this paper, a power allocation algorithm is proposed for EE to achieve the optimal EE in Massive MIMO. Based on the simplified expression, we develop a new algorithm to compute the optimal power allocation algorithm and it has been compared with the existing scheme from the previous literature. An improved water filling algorithm is proposed and embedded in the power allocation algorithm to maximize EE and Spectral Efficiency (SE). The numerical analysis of the simulation results indicates an improvement of 40% in EE and 50% in SE at the downlink transmission, compared to the other existing schemes. Furthermore, the results revealed that SE does not influence the EE enhancement after using the proposed algorithm as the number of Massive MIMO antenna at the Base Station (BS) increases.

Repetition Coding and Equal Power Allocation Scheme for JPEG Image Transmission over MIMO Systems

2016 ◽  
Vol 8 (3) ◽  
pp. 10-19
Author(s):  
Mujeeb Ahmed
Keyword(s):  
Power Allocation ◽  
Mimo Systems ◽  
Spatial Multiplexing ◽  
Quality Data ◽  
Smart Devices ◽  
Allocation Scheme ◽  
Repetition Coding ◽  
Equal Power Allocation ◽  
Equal Power ◽  
Antenna Systems

Multiple transmit and receive antenna systems have improved the reliability as well as data rate in a wireless communication system. Such advanced wireless architectures have empowered smart devices to fulfill the demand of multimedia content. Image is a major user generated content in wide range of applications, hence reliable transmission of image is an important research problem. New transmission and coding schemes that explore advantages of multiple antenna systems matched with source statistics have been developed. Based on a similar idea, an equal power allocation scheme for transmission of compressed images over multiple-input multiple-output (MIMO) systems employing partial repetition coding is proposed. The JPEG compression algorithm divides image into different quality layers. The proposed system repeats transmission of high quality data from more than one antenna as compared to the lower quality data which is transmitted using one antenna at most, in a particular time slot. A heuristic spatial multiplexing scheme is also proposed to optimally divide the bit stream chunks for transmission. Extensive simulations have shown that equal power allocation and repetition coding scheme is better as compared to reference schemes.

Study on the Resource Scheduling Algorithm for LTE-Advanced Downlink Systems

2014 ◽  
Vol 577 ◽  
pp. 1017-1021
Author(s):  
Hong Zhuo Wang ◽  
Zheng Hai Sun ◽  
Jun Wang ◽  
Fang Liu
Keyword(s):  
Power Allocation ◽  
Scheduling Algorithm ◽  
Resource Scheduling ◽  
Carrier Aggregation ◽  
High Complexity ◽  
Proportional Fair ◽  
Lte Advanced ◽  
Simulation Results ◽  
Equal Power Allocation ◽  
Equal Power

In the paper, the resource scheduling algorithm in the downlink of LTE-Advanced (LTE-A) assuming equal power allocation among subcarriers which adopted the technology of carrier aggregation (CA) is investigated. When the independent scheduling (INS) scheme is applied, the LTE users will acquire few resources because they cannot support CA technology. And the fairness of the system is disappointing. Focusing on the problem, a novel proportional fair (PF) scheduling algorithm based on INS is proposed. In the proposed method, the system fairness is well improved without bringing high complexity to the system. And also, we design a weigh factor which is related to the number of the carriers and the percentage of LTE users in the method. The simulation results show that the proposed algorithm can effectively increase the throughput of LTE users and improve the system fairness.

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