scholarly journals Adaptive Two-Level Frame Aggregation for Fairness and Efficiency in IEEE 802.11n Wireless LANs

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Minho Kim ◽  
Eun-Chan Park ◽  
Chong-Ho Choi
Keyword(s):  
Scheduling Algorithm ◽  
Local Area ◽  
Wireless Channel ◽  
Network Throughput ◽  
Channel Access ◽  
Frame Size ◽  
Ieee 802.11N ◽  
Frame Aggregation ◽  
Data Rates ◽  
Adaptation Scheme

This paper deals with the problem of performance degradation in wireless local area networks (WLANs) based on IEEE 802.11n. When a wireless channel is shared by heterogeneous stations that have different data rates and packet sizes, each station occupies a different amount of airtime because the basic channel access mechanism of WLAN was originally designed to provide fair chance of channel access, regardless of packet size and data rate. This leads to the degradation of overall network throughput and airtime fairness among stations, which is known as performance anomaly. To resolve this problem, we firstly formulate an optimization problem for a generalized two-level frame aggregation whose objective is to maximize the achievable throughput under the constraint of airtime fairness. Then, we propose a frame size adaptation scheme that controls the number of packets in an aggregated frame. The proposed scheme is fully compatible with the IEEE 802.11 standard and works in a distributed manner, which neither modifies the channel access mechanism nor resorts to a centralized scheduling algorithm. The extensive simulation results confirm that the proposed scheme tightly regulates the airtime usage of each station to be almost the same and significantly improves the overall network throughput compared to other existing schemes.

scholarly journals Improving Energy Efficiency in Idle Listening of IEEE 802.11 WLANs

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Muhammad Adnan ◽  
Eun-Chan Park
Keyword(s):  
Energy Efficiency ◽  
Ieee 802.11 ◽  
Power Saving ◽  
Local Area ◽  
Contention Window ◽  
Channel Access ◽  
Analysis Model ◽  
Frame Aggregation ◽  
Improve Energy Efficiency ◽  
Idle Listening

This paper aims to improve energy efficiency of IEEE 802.11 wireless local area networks (WLANs) by effectively dealing with idle listening (IL), which is required for channel sensing and is unavoidable in a contention-based channel access mechanism. Firstly, we show that IL is a dominant source of energy drain in WLANs and it cannot be effectively alleviated by the power saving mechanism proposed in the IEEE 802.11 standard. To solve this problem, we propose an energy-efficient mechanism that combines three schemes in a systematic way: downclocking, frame aggregation, and contention window adjustment. The downclocking scheme lets a station remain in a semisleep state when overhearing frames destined to neighbor stations, whereby the station consumes the minimal energy without impairing channel access capability. As well as decreasing the channel access overhead, the frame aggregation scheme prolongs the period of semisleep time. Moreover, by controlling the size of contention window based on the number of stations, the proposed mechanism decreases unnecessary IL time due to collision and retransmission. By deriving an analysis model and performing extensive simulations, we confirm that the proposed mechanism significantly improves the energy efficiency and throughput, by up to 2.8 and 1.8 times, respectively, compared to the conventional power saving mechanisms.

scholarly journals Hybrid Control of Contention Window and Frame Aggregation for Performance Enhancement in Multirate WLANs

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Muhammad Adnan ◽  
Eun-Chan Park
Keyword(s):  
Performance Enhancement ◽  
Hybrid Control ◽  
Transmission Rate ◽  
Local Area ◽  
Contention Window ◽  
Channel Access ◽  
Distributed Coordination ◽  
Frame Aggregation ◽  
Transmission Rates ◽  
Coordination Function

The IEEE 802.11 standard has been evolved to support multiple transmission rates in wireless local area networks (WLANs) to cope with diverse channel conditions and to increase throughput. However, when stations with different transmission rates coexist, the basic channel access mechanism of WLAN, distributed coordination function (DCF), not only fails to assure airtime fairness among competing stations but also decreases overall network throughput, because DCF was designed to provide fair opportunity of channel access, regardless of transmission rate. As an effective solution to this problem, we propose a hybrid control mechanism that integrates contention window control and frame aggregation. The former adjusts the size of contention window and differentiates the channel access opportunity depending on the transmission rates of stations. The latter controls the number of packets in the aggregated frame to tightly assure per-station airtime fairness with the reduced channel access overheads. Moreover, we derive an analytical model to evaluate the performance of the proposed mechanism in terms of throughput and fairness. Along with the analysis results, the extensive simulation results confirm that the proposed mechanism significantly increases the overall throughput by about three times compared to the conventional DCF, while assuring airtime fairness strictly.

scholarly journals Revisiting of Channel Access Mechanisms in Mobile Wireless Networks through Exploiting Physical Layer Technologies

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Junmei Yao ◽  
Jun Xu ◽  
Yue Ling Che ◽  
Kaishun Wu ◽  
Wei Lou
Keyword(s):  
Network Performance ◽  
Rapid Development ◽  
Interference Management ◽  
Local Area ◽  
Physical Layer ◽  
Network Throughput ◽  
Future Research ◽  
Channel Access ◽  
Node Mobility ◽  
Hidden Terminal

The wireless local area networks (WLANs) have been widely deployed with the rapid development of mobile devices and have further been brought into new applications with infrastructure mobility due to the growth of unmanned aerial vehicles (UAVs). However, the WLANs still face persistent challenge on increasing the network throughput to meet the customer’s requirement and fight against the node mobility. Interference is a well-known issue that would degrade the network performance due to the broadcast characteristics of the wireless signals. Moreover, with infrastructure mobility, the interference becomes the key obstacle in pursuing the channel capacity. Legacy interference management mechanism through the channel access control in the MAC layer design of the 802.11 standard has some well-known drawbacks, such as exposed and hidden terminal problems, inefficient rate adaptation, and retransmission schemes, making the efficient interference management an everlasting research topic over the years. Recently, interference management through exploiting physical layer mechanisms has attracted much research interest and has been proven to be a promising way to improve the network throughput, especially under the infrastructure mobility scenarios which provides more indicators for node dynamics. In this paper, we introduce a series of representative physical layer techniques and analyze how they are exploited for interference management to improve the network performance. We also provide some discussions about the research challenges and give potential future research topics in this area.

scholarly journals Performance Analysis of IEEE802.11ac DCF Enhancement for VHT with Frame Aggregation

2016 ◽  
Vol 4 (3) ◽  
pp. 17
Author(s):  
Zineb Machrouh ◽  
Abdellah Najid
Keyword(s):  
Performance Analysis ◽  
Local Area ◽  
Medium Access ◽  
Frame Aggregation ◽  
Channel Bonding ◽  
Data Rates ◽  
5 Ghz ◽  
Access Mechanisms ◽  
Control Layer ◽  
Very High

<strong>IEEE 802.11ac standard has brought several significant improvements compared to its predecessor IEEE 802.11n. It managed to break the Gigabits barrier with a combination of both refining older techniques and presenting new ones. The new enhancements such as channel bonding, beamforming, frames aggregation and finer modulation allow Wireless Local Area Networks (WLAN) the use of Very High Throughput (VHT). The physical layer (PHY) data rates are in the range of Gbps in the 5 GHz band. But the variety of releases and options available for this standard has left many ambiguities regarding its real capabilities. The Medium Access Control layer (MAC) throughput is influenced by several factors, causing the MAC efficiency to decrease. In this paper we present a performance analysis in the VHT with frame aggregation for different access mechanisms, different channels and different modulation schemes.</strong>

scholarly journals Call Admission Scheme for Multidimensional Traffic Assuming Finite Handoff User

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Md. Baitul Al Sadi ◽  
Afsana Nadia
Keyword(s):  
Cellular Network ◽  
Wireless Channel ◽  
Traffic Model ◽  
Channel Access ◽  
Handoff Call ◽  
Call Admission ◽  
Mobile Cellular ◽  
A Cell

Usually, the number of users within a cell in a mobile cellular network is considered infinite; hence,M/M/n/kmodel is appropriate for new originated traffic, but the number of ongoing calls around a cell is always finite. Hence, the traffic model of handoff call will beM/M/n/k/N. In this paper, aK-dimensional traffic model of a mobile cellular network is proposed using the combination of limited and unlimited users case. A new call admission scheme (CAS) is proposed based on both thinning scheme and fading condition. The fading condition of the wireless channel access to a handoff call is prioritized compared to newly originated calls.

Analysis of WRR scheduling algorithm frame size impact on CQ switch performance

2013 Africon ◽  
2013 ◽  
Author(s):  
Igor Radusinovic ◽  
Milutin Radonjic ◽  
Milica Pejanovic Djurisic
Keyword(s):  
Scheduling Algorithm ◽  
Frame Size ◽  
Switch Performance

scholarly journals Performance analysis of IEEE 802.11ac based WLAN in wireless communication systems

2019 ◽  
Vol 9 (2) ◽  
pp. 1131 ◽  
Author(s):  
A. Z. Yonis
Keyword(s):  
Communication Systems ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Multiple Input Multiple Output ◽  
Local Area ◽  
Area Network ◽  
Data Rates ◽  
Input Multiple Output ◽  
Ieee 802.11Ac ◽  
5 Ghz

<p><span lang="EN-US">IEEE 802.11ac based wireless local area network (WLAN) is emerging WiFi standard at 5 GHz, it is new gigabit-per-second standard providing premium services. IEEE 802.11ac accomplishes its crude speed increment by pushing on three distinct measurements firstly is more channel holding, expanded from a maximum of 80 MHz up to 160 MHz modes. Secondly, the denser modulation, now using 256-QAM, it has the ability to increase the data rates up to 7 Gbps using an 8×8 multiple input multiple output (MIMO). Finally, it provides high resolution for both narrow and medium bandwidth channels. This work presents a study to improve the performance of IEEE 802.11ac based WLAN system.</span></p>

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