A Novel Delay Model for IEEE 802.11

2012 ◽  
Vol 263-266 ◽  
pp. 1032-1036
Author(s):  
Chun Shi ◽  
Xian Hua Dai ◽  
Zheng Jie Deng ◽  
Shu Qian He
Keyword(s):  
Ieee 802.11 ◽  
Function Analysis ◽  
Full Time ◽  
Delay Model ◽  
Distributed Coordination ◽  
Node Number ◽  
802.11 Dcf ◽  
Real Performance ◽  
Coordination Function ◽  
Inter Frame

With the popularity of the IEEE 802.11 standards, many analytical delay studies for the Distributed Coordination Function (DCF) have been reported. In this paper, we analyze the additional idle durations that a tagged node needs to wait due to other nodes transmissions. Separating the distributed inter-frame space (DIFS) and extended inter-frame space (EIFS) durations from the full time of a successful transmission, we provide a correct function analysis of the DIFS and EIFS durations and build a more accurate delay model for the IEEE 802.11 DCF. The theoretical analysis and simulation results prove that the proposed delay model is coincident with the real performance when the node number increases.

Improving WLAN Performance by Modifying an IEEE 802.11 Protocol

2013 ◽  
pp. 15-32
Author(s):  
Nurul I. Sarkar
Keyword(s):  
Ieee 802.11 ◽  
Ad Hoc ◽  
Packet Delay ◽  
Distributed Coordination ◽  
Bandwidth Utilization ◽  
Medium Access ◽  
802.11 Dcf ◽  
802.11 Networks ◽  
Distributed Coordination Function ◽  
Coordination Function

One of the limitations of the IEEE 802.11 distributed coordination function (DCF) protocol is its low bandwidth utilization under medium-to-high traffic loads resulting in low throughput and high packet delay. To overcome performance problems, traditional IEEE 802.11 DCF (“DCF”) protocol is modified to the buffer unit multiple access (BUMA) protocol. The BUMA protocol achieves a better system performance by introducing a temporary buffer unit at the medium access control (MAC) layer to accumulate multiple packets and combine them into a single packet (with a header and a trailer) before transmission. This paper provides an in-depth performance evaluation (by simulation) of BUMA for multiuser ad hoc and infrastructure networks. Results obtained show that the BUMA is more efficient than that of DCF. The BUMA protocol is simple and its algorithm (software) can be upgraded to 802.11 networks requiring no hardware changes. The BUMA protocol is described and simulation results are presented to verify the performance.

scholarly journals Improving WLAN Performance by Modifying an IEEE 802.11 Protocol

2011 ◽  
Vol 1 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Nurul I. Sarkar
Keyword(s):  
Ieee 802.11 ◽  
Ad Hoc ◽  
Packet Delay ◽  
Distributed Coordination ◽  
Bandwidth Utilization ◽  
Medium Access ◽  
802.11 Dcf ◽  
Traffic Loads ◽  
802.11 Networks ◽  
Coordination Function

One of the limitations of the IEEE 802.11 distributed coordination function (DCF) protocol is its low bandwidth utilization under medium-to-high traffic loads resulting in low throughput and high packet delay. To overcome performance problems, traditional IEEE 802.11 DCF (“DCF”) protocol is modified to the buffer unit multiple access (BUMA) protocol. The BUMA protocol achieves a better system performance by introducing a temporary buffer unit at the medium access control (MAC) layer to accumulate multiple packets and combine them into a single packet (with a header and a trailer) before transmission. This paper provides an in-depth performance evaluation (by simulation) of BUMA for multiuser ad hoc and infrastructure networks. Results obtained show that the BUMA is more efficient than that of DCF. The BUMA protocol is simple and its algorithm (software) can be upgraded to 802.11 networks requiring no hardware changes. The BUMA protocol is described and simulation results are presented to verify the performance.

Throughput Analysis of IEEE 802.11 DCF with Modified Binary Exponential Backoff in Mobile Ad Hoc Networks

2010 ◽  
Vol 2 (3) ◽  
pp. 61-70
Author(s):  
Rishipal Singh ◽  
D. K. Lobiyal
Keyword(s):  
Wireless Networks ◽  
Ieee 802.11 ◽  
Spread Spectrum ◽  
Ad Hoc ◽  
Distributed Coordination ◽  
Medium Access ◽  
Binary Exponential Backoff ◽  
802.11 Dcf ◽  
Hoc Networks ◽  
Coordination Function

In the design of wireless networks, the medium access protocols have a very large impact on the performance of the network. The IEEE 802.11 is widely accepted technology for the Wireless LANs and is used by wireless networks. This paper presents an analysis of the performance of Distributed Coordination Function (DCF) for IEEE 802.11 under modified Binary Exponential Backoff (BEB) Algorithm using Frequency Hoping Spread Spectrum (FHSS). In the modified algorithm, the size of Contention Window (CW) has been changed with the factor of for the first four collisions and the size becomes double thereafter in each subsequent collision. This paper also covers the effects of various parameters in modified BEB Algorithm.

scholarly journals Enhancing the Selection of Backoff Interval Using Fuzzy Logic over Wireless Ad Hoc Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Radha Ranganathan ◽  
Kathiravan Kannan
Keyword(s):  
Fuzzy Logic ◽  
Ieee 802.11 ◽  
Ad Hoc ◽  
Distributed Coordination ◽  
Medium Access ◽  
Ieee 802.11 Dcf ◽  
802.11 Dcf ◽  
Effective Manner ◽  
Distributed Coordination Function ◽  
Coordination Function

IEEE 802.11 is the de facto standard for medium access over wireless ad hoc network. The collision avoidance mechanism (i.e., random binary exponential backoff—BEB) of IEEE 802.11 DCF (distributed coordination function) is inefficient and unfair especially under heavy load. In the literature, many algorithms have been proposed to tune the contention window (CW) size. However, these algorithms make every node select its backoff interval between [0, CW] in a random and uniform manner. This randomness is incorporated to avoid collisions among the nodes. But this random backoff interval can change the optimal order and frequency of channel access among competing nodes which results in unfairness and increased delay. In this paper, we propose an algorithm that schedules the medium access in a fair and effective manner. This algorithm enhances IEEE 802.11 DCF with additional level of contention resolution that prioritizes the contending nodes according to its queue length and waiting time. Each node computes its unique backoff interval using fuzzy logic based on the input parameters collected from contending nodes through overhearing. We evaluate our algorithm against IEEE 802.11, GDCF (gentle distributed coordination function) protocols using ns-2.35 simulator and show that our algorithm achieves good performance.

scholarly journals Performance Analysis of IEEE 802.11 DCF under Nonsaturation Condition

2008 ◽  
Vol 2008 ◽  
pp. 1-17 ◽  
Author(s):  
Yutae Lee ◽  
Min Young Chung ◽  
Tae-Jin Lee
Keyword(s):  
Ieee 802.11 ◽  
Multiple Access ◽  
Distributed Coordination ◽  
Carrier Sense Multiple Access ◽  
Ieee 802.11 Dcf ◽  
802.11 Dcf ◽  
Packet Collision ◽  
Access Scheme ◽  
Distributed Coordination Function ◽  
Coordination Function

Carrier sense multiple access with collision avoidance (CSMA/CA) methods are considered to be attractive MAC protocols for wireless LANs. IEEE 802.11 distributed coordination function (DCF) is a random channel access scheme based on CSMA/CA method and the binary slotted exponential backoff procedure to reduce the packet collision. In this paper, we propose a new analytical model for a nonsaturated IEEE 802.11 DCF network and evaluate its performance. We verify our model using simulations and show that our results agree with the simulations.

A Queuing Model for IEEE 802.11 DCF Performance Analysis

2013 ◽  
Vol 380-384 ◽  
pp. 1202-1209
Author(s):  
Xuan Chen ◽  
Yu Bin Xu ◽  
Lin Ma
Keyword(s):  
Ieee 802.11 ◽  
Network Performance ◽  
Distributed Coordination ◽  
Queuing Model ◽  
Traffic Conditions ◽  
Ieee 802.11 Dcf ◽  
802.11 Dcf ◽  
Proposed Model ◽  
Distributed Coordination Function ◽  
Coordination Function

A queuing model is proposed to analyze the performance of IEEE 802.11 Distributed Coordination Function (DCF). By regarding the network performance in the unsaturated case as the expected mean of the network performance in the different saturated cases, the proposed model extends the application scenarios from the saturated case to the nonsaturated case. The queuing model can be used to analyze the network performance and QoS parameters of the stations for different traffic conditions. In addition, this model also applies to the cases in shadow channels. Compared to the existing work based on the classic Markov model, the proposed model is more general and can be used in more complex and practical scenarios.

scholarly journals On the Optimization of the IEEE 802.11 DCF: A Cross-Layer Perspective

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Massimiliano Laddomada ◽  
Fabio Mesiti
Keyword(s):  
Ieee 802.11 ◽  
Operating Conditions ◽  
Packet Error Rate ◽  
Closed Form Expression ◽  
Cross Layer ◽  
Distributed Coordination ◽  
Data Link ◽  
802.11 Dcf ◽  
Channel Errors ◽  
Coordination Function

This paper is focused on the problem of optimizing the aggregate throughput of the distributed coordination function (DCF) employing the basic access mechanism at the data link layer of IEEE 802.11 protocols. We consider general operating conditions accounting for both nonsaturated and saturated traffic in the presence of transmission channel errors, as exemplified by the packet error rate . The main clue of this work stems from the relation that links the aggregate throughput of the network to the packet rate of the contending stations. In particular, we show that the aggregate throughput presents two clearly distinct operating regions that depend on the actual value of the packet rate with respect to a critical value , theoretically derived in this work. The behavior of paves the way to a cross-layer optimization algorithm, which proved to be effective for maximizing the aggregate throughput in a variety of network operating conditions. A nice consequence of the proposed optimization framework relies on the fact that the aggregate throughput can be predicted quite accurately with a simple, yet effective, closed-form expression. Finally, theoretical and simulation results are presented in order to unveil, as well as verify, the key ideas.

scholarly journals Improvement of Network Utility and Energy Efficiency in DSME based Internet of Things Networks

2020 ◽  
Vol 9 (3) ◽  
pp. 3158-3162
Keyword(s):  
Internet Of Things ◽  
Ieee 802.11 ◽  
Ieee 802.15.4 ◽  
Distributed Coordination ◽  
802.11 Dcf ◽  
Access Scheme ◽  
Distributed Coordination Function ◽  
Network Utility ◽  
Coordination Function ◽  
Ieee 802.15.4E

This paper provides a comparison between IEEE 802.11 and IEEE 802.15.4e standards in the context of Internet of Things (IoT). These emerging standards are the amendments of IEEE 802.11 and IEEE 802.15.4 to support IoT based applications. The 802.11 has a channel access scheme, Distributed coordination function (DCF). On the other hand, IEEE 802.15.4e introduces five MAC behavior mode. Among these five modes, DSME is well suited for IoT. A comparison between these two standards is discussed in this paper by using an analytical model and are validated through ns-3 simulations. Results show that the DSME show significant improvement in the performance of DSME when compared to the legacy IEEE 802.11 DCF.

scholarly journals Performance Analysis of Synchronous Multi-Radio Multi-Link MAC Protocols in IEEE 802.11be Extremely High Throughput WLANs

2020 ◽  
Vol 11 (1) ◽  
pp. 317
Author(s):  
Taewon Song ◽  
Taeyoon Kim
Keyword(s):  
Ieee 802.11 ◽  
Markov Chain Model ◽  
Careful Consideration ◽  
Mac Protocols ◽  
Media Access Control ◽  
Chain Model ◽  
Distributed Coordination ◽  
Media Access ◽  
Medium Access ◽  
Coordination Function

The representative media access control (MAC) mechanism of IEEE 802.11 is a distributed coordination function (DCF), which operates based on carrier-sense multiple access with collision avoidance (CSMA/CA) with binary exponential backoff. The next amendment of IEEE 802.11 being developed for future Wi-Fi by the task group-be is called IEEE 802.11be, where the multi-link operation is mainly discussed when it comes to MAC layer operation. The multi-link operation discussed in IEEE 802.11be allows multi-link devices to establish multiple links and operate them simultaneously. Since the medium access on a link may affect the other links, and the conventional MAC mechanism has just taken account of a single link, the DCF should be used after careful consideration for multi-link operation. In this paper, we summarize the DCFs being reviewed to support the multi-radio multi-link operation in IEEE 802.11be and analyze their performance using the Markov chain model. Throughout the extensive performance evaluation, we summarize each MAC protocol’s pros and cons and discuss essential findings of the candidate MAC protocols.

Distributed Approach for QoS Guarantee to Wireless Multimedia

2007 ◽  
pp. 195-201
Author(s):  
K. Chetan ◽  
P. Venkataram ◽  
R. Sircar
Keyword(s):  
Ieee 802.11 ◽  
Wireless Multimedia ◽  
Distributed Coordination ◽  
Access Method ◽  
Qos Guarantee ◽  
Distributed Approach ◽  
Research Areas ◽  
Distributed Coordination Function ◽  
Active Research ◽  
Coordination Function

Providing support for QoS at the MAC layer in the IEEE 802.11 is one of the very active research areas. There are various methods that are being worked out to achieve QoS at MAC level. In this article we describe a proposed enhancement to the DCF (distributed coordination function) access method to provide QoS guarantee for wireless multimedia applications.

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