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A Performance Study of the IEEE 802.11g PHY and MAC Layers over Heterogeneous and Homogeneous WLANs
Villase?or-González, L.;Portillo-Jiménez, C.;Sánchez-García, J.;
Ingeniería, investigación y tecnología , 2007,
Abstract: wireless local area networks (wlans) based on the 802.11 standard are being deployed with great success in a great variety of home, office and corporate environments. since the introduction of the 802.11 standard, multiple extensions have been proposed and approved by the ieee, namely the 802.11a, 802.11b and 802.11g standards. this work is related to the study and performance analysis of the ieee 802.11g physical (phy) and mac layers. the 802.11g is defined to operate in the 2.4 ghz band and it was designed to preserve backward compatibility with the 802.11b standard. hence it is important to present a study related to the performance of the mac and the phy operational modes in 802.11g, including the performance issues related to the phy operational modes which are designed to be compatible with 802.11b (i.e. heterogeneous wlans).
Adaptive Distributed Inter Frame Space for IEEE 802.11 MAC Protocol  [PDF]
Ja’afer AL-Saraireh, Saleh Saraireh, Mohammad Saraireh, Mohammed Bani Younis
Communications and Network (CN) , 2014, DOI: 10.4236/cn.2014.63018
Abstract:

In this research, an Adaptive Distributed Inter Frame Space (ADIFS) has been proposed for IEEE 802.11 Medium Access Control (MAC) protocol. The aim of this approach is to improve Quality of Services (QoS) for IEEE 802.11 MAC protocol in single-hop wireless network. The proposed approach is based on traffic type, Collision Rate (CR), Collision Rate Variation (CRV) and Packet Loss Rate. These parameters are used to adjust the DIFS at runtime. The adjusted DIFS is employed to enhance service differentiation at the MAC layer in single-hop wireless networks. The proposed approach contributes to the enhancement of the average QoS for high priority traffic by 32.9% and 33.4% for the 5 and 10 connections, respectively. While the average QoS for the low priority traffic is improved by 14.3% and 18.2% for the 5 and 10 connections, respectively. The results indicate that, the proposed approach contributes in the enhancement of the QoS in wireless network.

A MAC and PHY Cross-Layer Analytical Model for the Goodput an Networks Operating Under Basic Access and RTS/CTS DCF Schemesd Delay of IEEE 802.11a  [cached]
Roger Pierre Fabris Hoefel
Journal of Communications , 2006, DOI: 10.4304/jcm.1.6.1-8
Abstract: We have developed a theoretical cross-layer model that allows assessing the goodput and delay of IEEE 802.11 local area networks (WLANs) operating simultaneously under the distributed coordination function (DCF) basic access (BA) and request-to-send/clear-to-send (RTS/CTS) medium access control (MAC) protocols under saturated traffic over correlated fading channels. Acomparison between numerical and simulation results is carried out assuming the IEEE 802.11a PHY layer.
Frame Aggregation in Wireless Networks: Techniques and Issues
Saif Anwar,Othman Mohamed,Subramaniam Shamala,Abdul Hamid Nor
IETE Technical Review , 2011,
Abstract: The timing and headers overheads of IEEE 802.11 PHY and MAC layers consume a large part of the channel time leading to performance degradation especially at higher data rates. Several enhancements at both the PHY and MAC layers have been proposed in order to reduce these overheads and increase the channel utilization. A key enhancement is frame aggregation in which the timing and headers overheads are reduced by aggregating multiple frames into a single large frame and then transmit it in a single channel access. This paper addresses the frame aggregation techniques that have been proposed for the next generation wireless networks and the aggregation techniques that are adopted by IEEE 802.11n standard. It also highlights the aggregation issues that need to be investigated in order to further enhance the frame aggregation performance.
Rate Adaptation MAC Protocol for High Rate IEEE 802.11 WLANs
基于IEEE 802.11高速无线局域网的速率自适应MAC协议研究

Xi Yong,Huang Qing-yan,Wei Ji-bo,Wu Yu,
习勇
,黄清艳,魏急波,吴宇

电子与信息学报 , 2007,
Abstract: The current IEEE 802.11 PHYs provide multiple transmission rates, but in MAC layer, the rate adaptation algorithm is not specified. This paper studies rate adaptation schemes for high rate IEEE 802.11 WLANs MAC protocol. Firstly, an Enhanced ACKnowledgement (EACK) rate adaptation protocol is presented. In EACK, the MAC header is transmitted at basic rate and the channel state information is carried by ACK frame. EACK reacts to channel variations quickly while has fewer overheads. Then, a constant transmission duration scheme with EACK (CEACK) is proposed for high rate wireless LANs which can overcome the throughput upper limit of legacy IEEE 802.11 DCF MAC and has better temporal fairness performance in hybrid rates networks.
Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs  [cached]
Choi Woo-Yong
EURASIP Journal on Wireless Communications and Networking , 2009,
Abstract: We propose the efficient reliable multicast MAC protocol based on the connectivity information among the recipients. Enhancing the BMMM (Batch Mode Multicast MAC) protocol, the reliable multicast MAC protocol significantly reduces the RAK (Request for ACK) frame transmissions in a reasonable computational time and enhances the MAC performance. By the analytical performance analysis, the throughputs of the BMMM protocol and our proposed MAC protocol are derived. Numerical examples show that our proposed MAC protocol increases the reliable multicast MAC performance for IEEE 802.11 wireless LANs.
Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs  [cached]
Woo-Yong Choi
EURASIP Journal on Wireless Communications and Networking , 2009, DOI: 10.1155/2009/968408
Abstract: We propose the efficient reliable multicast MAC protocol based on the connectivity information among the recipients. Enhancing the BMMM (Batch Mode Multicast MAC) protocol, the reliable multicast MAC protocol significantly reduces the RAK (Request for ACK) frame transmissions in a reasonable computational time and enhances the MAC performance. By the analytical performance analysis, the throughputs of the BMMM protocol and our proposed MAC protocol are derived. Numerical examples show that our proposed MAC protocol increases the reliable multicast MAC performance for IEEE 802.11 wireless LANs.
Analysis on Open-Source Networks of MAC, Energy Model for IEEE 802.11 standards using QualNet Simulator
DHARAM VIR,DR. S.K.AGARWAL,DR. S.A.IMAM
International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering , 2013,
Abstract: In this paper, we efforts on the simulation of IEEE 802.11 standards Physical (PHY), Medium Access Control (MAC), and Energy model are investigating using QualNet network simulator. Routing data from source to destination is hard in Mobile Ad-Hoc Networks (MANET) due to the mobility of the network elements and lack of central administration. The main method for evaluating the performance of MANETs is simulation. The IEEE 802.11e Medium Access Control (MAC) is an emergingstandard to support Quality of Service (QoS). As we show the HCF scheduling algorithm is only for Constant Bit Rate (CBR)characteristics. However, a lot of real-time applications, such as video conferencing, have small variations in their packet sizes,sending rates or even have Constant Bit Rate (CBR) characteristics. In this paper performance of Ad-hoc On-demand Distance Vector (AODV) and Dynamic Source Routing (DSR) reactive routing protocol are studied by considering IEEE 802.11standards. Performance metrics like average end-to-end delay, average jitter, energy consumed in transmit and received modes, total broadcast sent and received and throughput are considered for investigating simulation scenario by varying network size in CBR with 10 mps node mobility. Also simulation has been carried out by varying mobility for scenario with 40 nodes.
Towards MAC/Anycast Diversity in IEEE 802.11n MIMO Networks  [PDF]
Anatolij Zubow,Robert Sombrutzki,Markus Scheidgen
Computer Science , 2012,
Abstract: Opportunistic Routing (OR) is a novel routing technique for wireless mesh networks that exploits the broadcast nature of the wireless medium. OR combines frames from multiple receivers and therefore creates a form of Spatial Diversity, called MAC Diversity. The gain from OR is especially high in networks where the majority of links has a high packet loss probability. The updated IEEE 802.11n standard improves the physical layer with the ability to use multiple transmit and receive antennas, i.e. Multiple-Input and Multiple-Output (MIMO), and therefore already offers spatial diversity on the physical layer, i.e. called Physical Diversity, which improves the reliability of a wireless link by reducing its error rate. In this paper we quantify the gain from MAC diversity as utilized by OR in the presence of PHY diversity as provided by a MIMO system like 802.11n. We experimented with an IEEE 802.11n indoor testbed and analyzed the nature of packet losses. Our experiment results show negligible MAC diversity gains for both interference-prone 2.4 GHz and interference-free 5 GHz channels when using 802.11n. This is different to the observations made with single antenna systems based on 802.11b/g, as well as in initial studies with 802.11n.
IEEE 802.11ax: High-Efficiency WLANs  [PDF]
Boris Bellalta
Computer Science , 2015,
Abstract: IEEE 802.11ax-2019 will replace both IEEE 802.11n-2009 and IEEE 802.11ac-2013 as the next high-throughput Wireless Local Area Network (WLAN) amendment. In this paper, we review the expected future WLAN scenarios and use-cases that justify the push for a new PHY/MAC IEEE 802.11 amendment. After that, we overview a set of new technical features that may be included in the IEEE 802.11ax-2019 amendment and describe both their advantages and drawbacks. Finally, we discuss some of the network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other on-going IEEE 802.11 amendments.
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