scholarly journals The Impact of Dynamic RTS Threshold Adjustment for IEEE 802.11 MAC Protocol

2009 ◽  
Vol 5 (1) ◽  
pp. 5-20 ◽  
Author(s):  
Mostafa Mjidi ◽  
Debasish Chakraborty ◽  
Naoki Nakamura ◽  
Norio Shiratori
Keyword(s):  
Ieee 802.11 ◽  
Data Transmission ◽  
Mac Protocol ◽  
Threshold Value ◽  
Local Area ◽  
Wireless Channel ◽  
Main Element ◽  
Medium Access ◽  
Hidden Terminal ◽  
The Impact

In recent years, wireless technologies and application received great attention. The Medium Access Control (MAC) protocol is the main element that determines the efficiency in sharing the limited communication bandwidth of the wireless channel in wireless local area networks (WLANs). IEEE 802.11 introduced the optional RTS/CTS handshaking mechanism to address the hidden terminal problem as well as to reduces the chance of collision in case of higher node density and traffic. RTS Threshold (RT) determines when RTS/CTS mechanism should be used and proved to be an important parameter for performance characteristics in data transmission. We first investigate to find a meaningful threshold value according to the network situation and determine the impact of using or disengaging the RTS/CTS optional mechanism and dynamically adjust the RTS Threshold to maximize data transmission. The results show a significant improvement over existing CSMA/CA and RTS/CTS schemes. Our adaptive scheme performed even better when data rate increases. We verify our proposed scheme both analytically and with extensive network simulation using ns-2.

scholarly journals Cross-Layer Analysis of Multi-Static RFID Systems Exploiting Capture Diversity

2021 ◽  
Author(s):  
Roberto Valentini ◽  
Piergiuseppe Di Marco ◽  
Roberto Alesii ◽  
Fortunato Santucci
Keyword(s):  
Mac Protocol ◽  
Wireless Channel ◽  
Cross Layer ◽  
Mac Layer ◽  
Medium Access ◽  
Rfid Systems ◽  
Layer Analysis ◽  
Passive Rfid ◽  
The Impact ◽  
Collision Mechanism

In this paper, we propose a framework for cross-layer analysis of multi-static passive RFID systems. The model takes into account details of the shared wireless channel, including fading and capture effect, whereas, at the medium access control (MAC) layer, the anti-collision mechanism proposed in the EPC Generation 2 standard is taken as a reference.<br>To address the complexity of the system model, we rely on a semi-analytical approach, that combines a moment matching approximation method to abstract the physical layer and Monte-Carlo simulations to describe the MAC dynamics.<br>Furthermore, based on the space diversity feature offered by the multi-static settings, we introduce the concept of capture deiversity and propose a modification to the standard to fully support this form of diversity.<br>Numerical results show the impact of deployment conditions and the relative positions of interrogator, tags, and detection points on the performance of tags' identification. We show how the number of detection points impacts the system performance under various channel conditions and MAC parameters' settings. Finally, we validate the proposed update of the MAC protocol, showing substantial performance improvement with respect to the standard collision resolution policy.

scholarly journals Design and Analysis of an Efficient and Reliable Mac Protocol for Vanets

2021 ◽  
Author(s):  
Khalid Abdel Hafeez
Keyword(s):  
High Stability ◽  
Mac Protocol ◽  
Network Capacity ◽  
Wireless Channel ◽  
Propagation Model ◽  
Ieee 802.11P ◽  
Inference System ◽  
Hidden Terminal ◽  
On The Road ◽  
The Impact

The increase number of vehicles on roads and the immense number of fatal accidents they cause have driven the research and development of new generation technologies to help drivers travel more safely. One major cause of traffic accidents is that drivers cannot consistently respond to the changing road conditions appropriately. In fact, most accidents could be avoided if drivers could obtain and use relevant information of the traffic that is beyond their vision using wireless communications technology. Recently, the IEEE community adopted the IEEE 802.11p standard as a main technology for VANETs. To test the feasibility of this technology, most researchers use simulations to evaluate its new applications and protocols due to the prohibitive cost of implementing real VANET setup. Therefore, we first analyze VANET’s wireless channel analytically and by simulations to predict its most appropriate propagation model and the communication range that minimizes the impact of the hidden terminal problem. Second, we derive a new mobility model that takes into account the vehicle’s follow-on safety rule, to accurately derive the relationship between vehicle’s speed and network density. It is expected that broadcasting and multi hop communications will be dominant in VANETs safety applications and protocols. Therefore, a Network Topology p-Persistence (NTPP) scheme is proposed to alleviate the impact of the broadcast storm problem. NTPP is based on vehicles’ knowledge of their neighbors in their range and traffic parameters to reduce the channel contention, redundant re-broadcasts and message travel time and to increase the emergency message reception rate. We analyze the reliability of the IEEE 802.11p in VANETs safety and warning applications scope taking into consideration different factors. It is shown analytically and by extensive simulations that the current DSRC specifications may lead to undesirable performance under harsh vehicular environments. Therefore, a novel Distributed Multichannel and Mobility Aware Cluster-based MAC Protocol (DMCMAC) is proposed to alleviate the impact of the hidden terminal problem, increase the network capacity and reliability. Cluster heads in DMCMAC are elected and re-elected in a distributed manner according to their relative speed and distance from their cluster members. The high stability of DMCMAC results from its adaptability to drivers’ behavior on the road and its learning process to predict the future speed and position of all cluster members using the fuzzy logic inference system. The reliability of DMCMAC is analyzed and compared with other protocols. It is shown by simulations that DMCMAC has high stability, its performance exceeds other protocols and can achieve a timely and reliable delivery of emergency messages to their intended recipients which make it more suitable for VANETs. iv

scholarly journals Majority Voting-Based MAC Protocol for Exploiting Link-Layer Diversity in Wireless Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2706
Author(s):  
Jaehyoung Park ◽  
Yonggang Kim ◽  
Gyungmin Kim ◽  
Hyuk Lim
Keyword(s):  
Data Transmission ◽  
Software Defined Radio ◽  
Mac Protocol ◽  
Local Area ◽  
Majority Voting ◽  
Medium Access ◽  
Link Layer ◽  
Error Corrections ◽  
Carrier Sensing ◽  
Interference Signals

In wireless local area networks (WLANs), the effect of interference signals between neighboring nodes increases as the number of wireless nodes using limited radio frequency resources in a limited space increases, which can significantly degrade the reliability of data transmission. In high-density WLANs, there can be several neighboring access points (APs) that can receive uplink transmission from a station. In conventional medium access control (MAC) protocols, uplink data frames containing errors or transmitted from a non-associated station are discarded at APs. Alternatively, we propose a MAC protocol using redundant wireless links between neighboring APs and the non-associated stations. In the proposed MAC protocol, we consider a centralized WLAN with a control node that performs error corrections of erroneous uplink data frames via a majority voting algorithm-based link-layer diversity scheme using uplink data received from multiple APs to increase the reliability of data transmission. In addition, we propose an adaptive carrier sensing ranging mechanism to improve the uplink network throughput in the proposed centralized WLAN system. Further, we conduct simulation studies and software-defined radio-based experiments to evaluate the performance of the proposed MAC protocol in various WLAN scenarios.

scholarly journals Cross-Layer Analysis of Multi-Static RFID Systems Exploiting Capture Diversity

2021 ◽  
Author(s):  
Roberto Valentini ◽  
Piergiuseppe Di Marco ◽  
Roberto Alesii ◽  
Fortunato Santucci
Keyword(s):  
Mac Protocol ◽  
Wireless Channel ◽  
Cross Layer ◽  
Mac Layer ◽  
Medium Access ◽  
Rfid Systems ◽  
Layer Analysis ◽  
Passive Rfid ◽  
The Impact ◽  
Collision Mechanism

In this paper, we propose a framework for cross-layer analysis of multi-static passive RFID systems. The model takes into account details of the shared wireless channel, including fading and capture effect, whereas, at the medium access control (MAC) layer, the anti-collision mechanism proposed in the EPC Generation 2 standard is taken as a reference.<br>To address the complexity of the system model, we rely on a semi-analytical approach, that combines a moment matching approximation method to abstract the physical layer and Monte-Carlo simulations to describe the MAC dynamics.<br>Furthermore, based on the space diversity feature offered by the multi-static settings, we introduce the concept of capture deiversity and propose a modification to the standard to fully support this form of diversity.<br>Numerical results show the impact of deployment conditions and the relative positions of interrogator, tags, and detection points on the performance of tags' identification. We show how the number of detection points impacts the system performance under various channel conditions and MAC parameters' settings. Finally, we validate the proposed update of the MAC protocol, showing substantial performance improvement with respect to the standard collision resolution policy.

scholarly journals Design and Analysis of an Efficient and Reliable Mac Protocol for Vanets

2021 ◽  
Author(s):  
Khalid Abdel Hafeez
Keyword(s):  
High Stability ◽  
Mac Protocol ◽  
Network Capacity ◽  
Wireless Channel ◽  
Propagation Model ◽  
Ieee 802.11P ◽  
Inference System ◽  
Hidden Terminal ◽  
On The Road ◽  
The Impact

The increase number of vehicles on roads and the immense number of fatal accidents they cause have driven the research and development of new generation technologies to help drivers travel more safely. One major cause of traffic accidents is that drivers cannot consistently respond to the changing road conditions appropriately. In fact, most accidents could be avoided if drivers could obtain and use relevant information of the traffic that is beyond their vision using wireless communications technology. Recently, the IEEE community adopted the IEEE 802.11p standard as a main technology for VANETs. To test the feasibility of this technology, most researchers use simulations to evaluate its new applications and protocols due to the prohibitive cost of implementing real VANET setup. Therefore, we first analyze VANET’s wireless channel analytically and by simulations to predict its most appropriate propagation model and the communication range that minimizes the impact of the hidden terminal problem. Second, we derive a new mobility model that takes into account the vehicle’s follow-on safety rule, to accurately derive the relationship between vehicle’s speed and network density. It is expected that broadcasting and multi hop communications will be dominant in VANETs safety applications and protocols. Therefore, a Network Topology p-Persistence (NTPP) scheme is proposed to alleviate the impact of the broadcast storm problem. NTPP is based on vehicles’ knowledge of their neighbors in their range and traffic parameters to reduce the channel contention, redundant re-broadcasts and message travel time and to increase the emergency message reception rate. We analyze the reliability of the IEEE 802.11p in VANETs safety and warning applications scope taking into consideration different factors. It is shown analytically and by extensive simulations that the current DSRC specifications may lead to undesirable performance under harsh vehicular environments. Therefore, a novel Distributed Multichannel and Mobility Aware Cluster-based MAC Protocol (DMCMAC) is proposed to alleviate the impact of the hidden terminal problem, increase the network capacity and reliability. Cluster heads in DMCMAC are elected and re-elected in a distributed manner according to their relative speed and distance from their cluster members. The high stability of DMCMAC results from its adaptability to drivers’ behavior on the road and its learning process to predict the future speed and position of all cluster members using the fuzzy logic inference system. The reliability of DMCMAC is analyzed and compared with other protocols. It is shown by simulations that DMCMAC has high stability, its performance exceeds other protocols and can achieve a timely and reliable delivery of emergency messages to their intended recipients which make it more suitable for VANETs. iv

TRIPLEPR-MAC: A Triple Queue Priority Based Medium Access Control Protocol for Wireless Sensor Network

2019 ◽  
Vol 09 ◽  
Author(s):  
Rinkuben N. Patel ◽  
Nirav V. Bhatt
Keyword(s):  
Sensor Network ◽  
Data Transmission ◽  
Energy Efficient ◽  
Power Efficiency ◽  
Mac Protocol ◽  
Medium Access Control Protocol ◽  
Quality Factors ◽  
Medium Access ◽  
Critical Fields ◽  
Storage Unit

Background: WSN is a network of smart tiny electromechanical devices named as sensors. Sensors perform various tasks like sensing the environment as per its range, transmit the data using transmission units, store the data in the storage unit and perform an action based on captured data. As they are installed in an unfriendly environment, to recharge the sensors are not possible every time which leads to a limited lifetime of a network. To enhance the life of a sensor network, the network required energy-efficient protocols. Various energy-efficient MAC protocols are developed by Research community, but very few of them are integrated with the priority-based environment which performs the priority-based data transmission. Another challenge of WSN is, most of the WSN areas are delay-sensitive because it is implemented in critical fields like military, disaster management, and health monitoring. Energy, Delay, and throughput are major quality factors that affect the sensor network. Objective: In this paper, the aim is to design and develop a MAC Protocol for a field like the military where the system requires energy efficiency and priority-based data transmission. Method: In the proposed model, the cluster-based network with priority queues are formed that can achieve higher power efficiency and less delay for sensitive data. Results: In this research simulation of Proposed MAC, TMAC and SMAC are done with different numbers of nodes, same inter-packet intervals, and variant inter-packet intervals. Based on the script simulation, result graphs are generated. Conclusion: The proposed work achieves greater lifetime compared to TMAC and SMAC using priority-based data transmission.

scholarly journals Performance Analysis of Wireless Local Area Network for a High-/Low-Priority Traffic Ratio at Different Numbers of Access Categories

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 693
Author(s):  
Kvitoslava Obelovska ◽  
Olga Panova ◽  
Vincent Karovič
Keyword(s):  
Network Performance ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Local Area ◽  
Area Network ◽  
Large Network ◽  
Medium Access ◽  
Massive Growth ◽  
Adaptive Adjustment ◽  
The Impact

The performance of Wireless Local Area Network (WLAN) is highly dependent on the processes that are implemented in the Medium Access Control (MAC) sublayer regulated by the IEEE 802.11 standard. In turn, various parameters affect the performance of the MAC sublayer, the most important of which is the number of stations in the network and the offered load. With the massive growth of multimedia traffic, research of the network performance depending on traffic types is relevant. In this paper, we present the impact of a high-/low-priority traffic ratio on WLAN performance with different numbers of access categories. The simulation results show different impact of high-/low-priority traffic ratio on the performance of the MAC sublayer of wireless LANs depending on different network-sizes and on network conditions. Performance of the large network with two access categories and with the prevalent high-priority traffic is significantly higher than in the case of using four categories on the MAC sublayer. This allows us to conclude that the performance improvement of the large network with the prevalent high-priority traffic can be achieved by an adaptive adjustment of the access categories number on the MAC sublayer.

FH-MAC

2011 ◽  
pp. 313-329
Author(s):  
Djamel Tandjaoui ◽  
Messaoud Doudou ◽  
Imed Romdhani
Keyword(s):  
Access Control ◽  
Medium Access Control ◽  
Ieee 802.11 ◽  
Wireless Mesh Networks ◽  
Control Method ◽  
Mesh Networks ◽  
Mac Protocol ◽  
Medium Access ◽  
Wireless Mesh ◽  
Channel Diversity

In this article, the authors propose a new hybrid MAC protocol named H-MAC for wireless mesh networks. This protocol combines CSMA and TDMA schemes according to the contention level. In addition, it exploits channel diversity and provides a medium access control method that ensures the QoS requirements. Using ns-2 simulator, we have implemented and compared H-MAC with other MAC protocol used in Wireless Network. The results showed that H-MAC performs better compared to Z-MAC, IEEE 802.11 and LCM-MAC.

FH-MAC

2009 ◽  
Vol 1 (4) ◽  
pp. 40-56
Author(s):  
Djamel Tandjaoui ◽  
Messaoud Doudou ◽  
Imed Romdhani
Keyword(s):  
Access Control ◽  
Medium Access Control ◽  
Ieee 802.11 ◽  
Wireless Mesh Networks ◽  
Control Method ◽  
Mesh Networks ◽  
Mac Protocol ◽  
Medium Access ◽  
Wireless Mesh ◽  
Channel Diversity

In this article, the authors propose a new hybrid MAC protocol named H-MAC for wireless mesh networks. This protocol combines CSMA and TDMA schemes according to the contention level. In addition, it exploits channel diversity and provides a medium access control method that ensures the QoS requirements. Using ns-2 simulator, we have implemented and compared H-MAC with other MAC protocol used in Wireless Network. The results showed that H-MAC performs better compared to Z-MAC, IEEE 802.11 and LCM-MAC.

A Slotted Multichannel MAC Protocol for Fair Resource Allocation in VANET

2018 ◽  
Vol 9 (3) ◽  
pp. 45-59 ◽  
Author(s):  
Pant Varun Prakash ◽  
Saumya Tripathi ◽  
Raghavendra Pal ◽  
Arun Prakash
Keyword(s):  
Mac Protocol ◽  
Cluster Head ◽  
Ieee 802.11P ◽  
Medium Access ◽  
Service Channel ◽  
Packet Delivery ◽  
Vehicle Density ◽  
Hidden Terminal ◽  
Future Data ◽  
Multichannel Mac

This article proposes a slotted multichannel medium access control (SMMAC) protocol for VANETs to reduce CCH congestion, decrease RSU dependency, increase safety and data packet's reliability and improve fairness among vehicles. The main entity is the cluster head that not only notifies all the vehicles under the same cluster about the present state of service channel and future data transmissions but also imposes a condition on the maximum number of vehicles allowed inside a cluster. Controlled vehicle density reduces CCH collisions and as a result, it makes the protocol better in terms of packet delivery. To eliminate the inter-cluster hidden terminal problem, in the proposed algorithm, each cluster uses a service channel different from its neighboring cluster. Analyzing the system for both dense and sparse scenario it can be seen through simulation results that the proposed protocol performs much better in comparison to IEEE 802.11p with respect to Throughput, PDR and Delay.

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