scholarly journals A Power Control Scheme to Exploit Capture Effect with Fairness Consideration in WLAN

2021 ◽  
Author(s):  
Szu-Lin Su ◽  
Tsung-Hsiu Chih ◽  
Yuan-Chun Tsai ◽  
Hsieh-Cheng Liao ◽  
Yu-Chia Wang
Keyword(s):  
Power Control ◽  
Window Size ◽  
Access Point ◽  
Mass Function ◽  
System Throughput ◽  
Probability Mass Function ◽  
Cross Layer Design ◽  
Capture Effect ◽  
Medium Access ◽  
Control Scheme

AbstractIn this paper, we develop a physical/medium-access-control cross layer design to improve system throughput with the consideration of fairness for IEEE 802.11 WLAN. From PHY layer perspective, when an access collision occurs, the access point can still decode the corresponding data successfully if the received signal to interference plus noise ratio is larger than the threshold. This phenomenon is referred to as the capture effect. To improve system throughput, this work proposes a Differential Reception-Power Power Control scheme to take advantage of the capture effect. However, the proposed power control scheme cannot provide a fair transmission environment even though it improves the system throughput. To resolve this problem, this work proposes two methods: the adjustment of contention window size and the modification of probability mass function for the selection of the backoff value. The simulation results demonstrate that the proposed schemes can not only remarkably improve system throughput, but also provide a fair transmission environment.

scholarly journals Energy Efficiency TDMA/CSMA Hybrid Protocol with Power Control for WSN

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Xin Yang ◽  
Ling Wang ◽  
Jian Xie ◽  
Zhaolin Zhang
Keyword(s):  
Energy Efficiency ◽  
Power Control ◽  
Multiple Access ◽  
Carrier Sense Multiple Access ◽  
Mac Layer ◽  
Medium Access ◽  
Practical Applications ◽  
Control Scheme ◽  
Time Division ◽  
The Internet Of Things

Wireless sensors network (WSN) is widely used in the Internet of Things at present. However, limited energy source is a critical problem in the improvement and practical applications of WSN, so it is necessary to improve the energy efficiency. As another important evaluation criterion of transmission performance, throughput should be improved too. To mitigate both of the problems at the same time, by taking the advantages of Time Division Multiple Access (TDMA) and Carrier Sense Multiple Access (CSMA) at the medium access control (MAC) layer of WSN, we propose a hybrid TDMA/CSMA MAC layer protocol. Meanwhile, we design a novel power control scheme to further reduce the energy consumption and optimize the transmission slots. The simulation results demonstrate that the proposed protocol significantly improves the throughput and energy efficiency.

scholarly journals A Joint Strategy for Fair and Efficient Energy Usage in WLANs in the Presence of Capture Effect

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 386
Author(s):  
Bilal Khan ◽  
Rana Rehman ◽  
Byung-Seo Kim
Keyword(s):  
Energy Efficiency ◽  
Power Control ◽  
Access Point ◽  
Local Area ◽  
Contention Window ◽  
Transmission Power ◽  
Capture Effect ◽  
Analysis Model ◽  
Transmission Power Control ◽  
Joint Strategy

Capture effect has been shown as a physical layer (PHY) phenomenon of modern wireless devices that improves the performance of wireless local area networks (WLANs) in terms of throughput. In this paper, however, we explore the effect of PHY capture in the domain of energy efficiency. Analysis model that takes into account the effect of PHY capture is backed up by ns-2 simulations show that capture effect improves energy efficiency of WLAN by 20%. This improvement, however, results in unfairness, i.e, a group of nodes located far away from the Access Point (AP) is three times less energy efficient than the group of nodes located closer to the AP. To resolve the unfairness caused by the capture effect, furthermore, this paper proposes a joint strategy of adaptive transmission power control (ATXPR) and contention window adjustment (CWADJ). Namely, a node that suffers transmission failure due to another node capturing the channel steps up its transmission power according to the transmission power control algorithm and refrains from increasing its contention window according to contention window adjustment mechanism, respectively. Our proposed joint strategy is 99% fair while maintaining overall energy efficiency of the network.

scholarly journals Hierarchical Slotted Wireless Random Channel Access with Power Control

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Abdelillah Karouit ◽  
Luis Orozco Barbosa ◽  
Fernando Ramírez-Mireles ◽  
Abdelkrim Haqiq
Keyword(s):  
Power Control ◽  
Power Level ◽  
Random Access ◽  
Packet Transmission ◽  
System Throughput ◽  
Channel Access ◽  
Access Scheme ◽  
Control Scheme ◽  
Average System

This paper introduces a hierarchical Wireless Random Access scheme based on power control where intelligence is split among the mobile users in order to drive the outcome of the system towards an efficient point. The hierarchical game is obtained by introducing a special user who plays the role of altruistic leader whereas the other users assume the role of followers. We define the power control scheme in such a way that the leader_first chooses the lowest power to transmit its packets amongNavailable levels whereas the followers re-transmit by randomly choosing a power level picked fromN-1higher distinct power levels. Using a 3D Markovian model, we compute the steady state of the system and derive the average system throughput and expected packet transmission delay. Our numerical results show that the proposed scheme considerably improves the global performance of the system avoiding the well known throughput collapse at high loads commonly characterizing most random channel access mechanisms.

scholarly journals Detecting Different Road Infrastructural Elements Based on the Stochastic Characterization of Speed Patterns

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mario Muñoz-Organero ◽  
Ramona Ruiz-Blázquez
Keyword(s):  
Total Variation ◽  
Traffic Congestion ◽  
Automatic Detection ◽  
Mass Function ◽  
Total Variation Distance ◽  
Statistical Moments ◽  
Probability Mass Function ◽  
Traffic Lights ◽  
Traffic Conditions ◽  
Variation Distance

The automatic detection of road related information using data from sensors while driving has many potential applications such as traffic congestion detection or automatic routable map generation. This paper focuses on the automatic detection of road elements based on GPS data from on-vehicle systems. A new algorithm is developed that uses the total variation distance instead of the statistical moments to improve the classification accuracy. The algorithm is validated for detecting traffic lights, roundabouts, and street-crossings in a real scenario and the obtained accuracy (0.75) improves the best results using previous approaches based on statistical moments based features (0.71). Each road element to be detected is characterized as a vector of speeds measured when a driver goes through it. We first eliminate the speed samples in congested traffic conditions which are not comparable with clear traffic conditions and would contaminate the dataset. Then, we calculate the probability mass function for the speed (in 1 m/s intervals) at each point. The total variation distance is then used to find the similarity among different points of interest (which can contain a similar road element or a different one). Finally, a k-NN approach is used for assigning a class to each unlabelled element.

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