Transmit Power and Rate Control for Spatial Reuse in Dense Wireless LANs

Author(s):  
Michael Knitter ◽  
Ruediger Kays ◽  
Wolfgang Endemann

Spatial reuse is an approach to better utilize the wireless medium in dense networks. In contrast to time multiplexed channel access, the idea is to allow a certain level of interference between parallel transmitting links. Depending on transmit power and rate settings, such parallel transmissions may result in increased overall system performance. This paper presents a systematic approach to model dense networks and optimize transmit power and rate settings for best total system performance. It discusses driving factors and limitations for spatial reuse. The paper introduces two algorithms for concurrent optimal transmit power and rate selection. System simulations using a fading channel model compare the performance of the algorithms against CSMA/CA. The simulation results show that average system performance can be increased by 100% and more.

2016 ◽  
Vol 11 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Tomas Cuzanauskas ◽  
Aurimas Anskaitis

Abstract Easy usage and integration with various applications made IEEE 802.11 one of the most used technologies these days, both at home and business premises. Over the years, there have been many additional improvements to the 802.11 standards. Nevertheless, the algorithms and Media Access Control (MAC) layer methods are almost the same as in previous Wi-Fi versions. In this paper, a set of methods to improve the total system capacity is proposed – such as efficient transmit power management based on Game Theory with a custom wireless medium protocol. The transmit power management and wireless medium protocol is verified by both simulation and real application scenarios. The results conclude that the capacity of the proposed wireless medium protocol is overall 20 percent higher than the standard 802.11 wireless medium access protocols. Additional TCP Acknowledgment filtering, which was tested together with the proposed wireless medium access protocol, can provide up to 10-percent-higher TCP throughput in high-density scenarios, especially for asymmetrical traffic cases. The conducted research suggests that efficient power management could result in lighter transmit power allocation rules that are currently set by the local regulators for current Wi-Fi devices. Thus, better propagation characteristics and wireless medium management would lead to an overall higher wireless system capacity.


2020 ◽  
Vol 14 ◽  
Author(s):  
Keerti Tiwari

: Multiple-input multiple-output (MIMO) systems have been endorsed to enable future wireless communication requirements. The efficient system designing appeals an appropriate channel model, that considers all the dominating effects of wireless environment. Therefore, some complex or less analytically acquiescent composite channel models have been proposed typically for single-input single-output (SISO) systems. These models are explicitly employed for mobile applications, though, we need a specific study of a model for MIMO system which can deal with radar clutters and different indoor/outdoor and mobile communication environments. Subsequently, the performance enhancement of MIMO system is also required in such scenario. The system performance enhancement can be examined by low error rate and high capacity using spatial diversity and spatial multiplexing respectively. Furthermore, for a more feasible and practical system modeling, we require a generalized noise model along with a composite channel model. Thus, all the patents related to MIMO channel models are revised to achieve the near optimal system performance in real world scenario. This review paper offers the methods to improve MIMO system performance in less and severe fading as well as shadowing environment and focused on a composite Weibull-gamma fading model. The development is the collective effects of selecting the appropriate channel models, spatial multiplexing/detection and spatial diversity techniques both at the transmitter and the receivers in the presence of arbitrary noise.


Author(s):  
Sarasij Das ◽  
Nagendra Rao P S

This paper is the outcome of an attempt in mining recorded power system operational data in order to get new insight to practical power system behavior. Data mining, in general, is essentially finding new relations between data sets by analyzing well known or recorded data. In this effort we make use of the recorded data of the Southern regional grid of India. Some interesting relations at the total system level between frequency, total MW/MVAr generation, and average system voltage have been obtained. The aim of this work is to highlight the potential of data mining for power system applications and also some of the concerns that need to be addressed to make such efforts more useful.


1986 ◽  
Vol 30 (9) ◽  
pp. 905-907
Author(s):  
Robert M. Elton

The MANPRINT (Manpower and Personnel Integration) Program is a comprehensive program designed to enhance human performance and reliability during weapon system development with the overall goal – of optimizing total system performance. Total system performance is a function of equipment performance and human performance as they are affected under varying environmental conditions which includes physical, social and operational conditions. The challenge the U.S. Army has today is to ensure these issues are addressed early in and continuously throughout the design process.


Author(s):  
Wellington E. Smith

Many processing systems, such as manufacturing assembly lines, can be described as a series of discrete operations performed on discrete units being processed. To evaluate the effectiveness of operators in such systems or to determine the best way to improve their performance, it is necessary to have a performance measure that relates to total system effectiveness. Current techniques measure operator performance in terms of time and errors, but they provide little predictive ability as to the effects of these parameters. To relate time and yield measures to a single criterion of system performance, a method has been developed for evaluating operator effectiveness in a series processing system that processes discrete items in large quantities. By recognizing and dealing with the fact that rejects at the end of series process are more expensive than at the beginning of the process, statements are developed for measuring performance in terms of its actual effect on the system. Concepts and methods are presented for measuring total system performance, performance of any segment of the system, total performance of any operator, and the effects of time and accuracy on operator performance.


Author(s):  
George J. Saulnier ◽  
K. Patrick Lee ◽  
Donald A. Kalinich ◽  
S. David Sevougian ◽  
Jerry A. McNeish

The total-system performance assessment (TSPA) model for the final environmental impact statement (FEIS) for the potential high-level nuclear-waste repository at Yucca Mountain, Nevada was developed from a series of analyses and model studies of the Yucca Mountain site. The U.S. Department of Energy (DOE) has recommended the Yucca Mountain, Nevada site for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. In May 2001, the DOE released the Yucca Mountain Science and Engineering Report (S&ER) for public review and comment. The S&ER summarizes more than 20 years of scientific and engineering studies supporting the site recommendation (SR). Following internal reviews of the S&ER and other documents, the DOE performed supplemental analyses of uncertainty in support of the SR as summarized in the Supplemental Science and Performance Analysis (SSPA) reports [2, 3]. The SSPA (1) provided insights into the impact of new scientific data and improved models and (2) evaluated a range of thermal operating modes and their effect on the predicted performance of a potential repository. The various updated component models for the SSPA resulted in a modified TSPA model, referred to as the supplemental TSPA model or SSPA TSPA model capturing the combined effects of the alternative model representations on system performance. The SSPA TSPA model was the basis for analyses for the FEIS for the Yucca Mountain site. However, after completion of the SSPA, the U.S. Environmental Protection Agency (EPA) released its final radiation-protection standards for the potential repository at Yucca Mountain (40 CFR Part 197). Compliance with the regulation required modification of several of the component models (e.g., the biosphere transport model and the saturated-zone transport model) in order to evaluate repository performance against the new standards. These changes were incorporated into the SSPA TSPA model. The resulting FEIS TSPA model, known as the “integrated TSPA model,” was used to perform the calculations presented in this report. The results of calculations using the FEIS TSPA model under a non-disruptive scenario, show that the potential disposal of commercial and DOE waste at a Yucca Mountain repository would not produce releases to the environment that would exceed the regulatory standards promulgated in the EPA Final Rule 10 CFR 197 and the NRC Final Rule 10 CFR 63 for both individual protection and groundwater protection. The analyses also show that both the high and low-temperature operating modes result in similar mean annual dose to the reasonably maximally exposed individual (RMEI). Further, the analyses show that consideration of intrusive and extrusive igneous events, human intrusion, or inclusion of the potential inventory of all radioactive material in the commercial and DOE inventory would not exceed those published standards.


2019 ◽  
Vol 9 (7) ◽  
pp. 1391 ◽  
Author(s):  
Xiangwei Bai ◽  
Qing Li ◽  
Yanqun Tang

In this paper, a low-complexity multi-cell resource allocation algorithm with a near-optimal system throughput is proposed to resolve the conflict between the high system throughput and low complexity of indoor visible light communication ultra-dense networks (VLC-UDNs). First, by establishing the optimal model of the resource allocation problem in each cell, we concluded that the problem is a convex optimization problem. After this, the analytic formula of the normalized scaling factor of each terminal for resource allocation is derived after reasonable approximate treatment. The resource allocation algorithm is subsequently proposed. Finally, the complexity analysis shows that the proposed algorithm has polynomial complexity, which is lower than the classical optimal inter-point method. The simulation results show that the proposed method achieves a improvement of 57% in performance in terms of the average system throughput and improvement of 67% in performance in terms of the quality of service (QoS) guarantee against the required data rate proportion allocation (RDR-PA) method.


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