ANALISIS PERBANDINGAN KINERJA TRANSPORT PROTOCOL PADA WIRELESS LAN DENGAN MENGGUNAKAN METODE DCF DAN DCF

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
I Gusti Ngurah Dwi Mulyartha ◽  
Nurain Silalahi ◽  
Nyoman Bogi A. K.
Keyword(s):  
Ad Hoc Network ◽  
Wireless Lan ◽  
Ad Hoc ◽  
Transport Protocol ◽  
Distributed Coordination ◽  
Mac Layer ◽  
Medium Access ◽  
Distributed Coordination Function ◽  
Infrastructure Network ◽  
Coordination Function

EEE 802.11 adalah protokol standar yang digunakan pada wireless LAN dan memiliki Medium Access Control (MAC) layer yang mendukung pengiriman data tak sinkron (asynchronous) untuk jaringan wireless baik pada infrastructure network dan ad hoc network. MAC menggunakan dua metode akses yaitu Point Coordination Function (PCF) dan Distributed Coordination Function (DCF), dimana DCF dikembangkan menjadi DCF+. Penelitian ini mensimulasikan ad hoc Network menggunakan perangkat bantu Borland Delphi dan dari hasil simulasi dianalisa performansi dari MAC dengan membandingkan parameter Throughput, Delay, Goodput dan Fairness antara metode DCF dan DCF+.

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 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 Latency and Jitter Analysis for IEEE 802.11e Wireless LANs

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Sungkwan Youm ◽  
Eui-Jik Kim
Keyword(s):  
Local Area ◽  
Ieee 802.11E ◽  
Distributed Coordination ◽  
Mac Layer ◽  
Medium Access ◽  
Distributed Coordination Function ◽  
Packet Latency ◽  
Coordination Function ◽  
The Voice

This paper presents a numerical analysis of latency and jitter for IEEE 802.11e wireless local area networks (WLANs) in a saturation condition, by using a Markov model. We use this model to explicate how the enhanced distributed coordination function (EDCF) differentiates classes of service and to characterize the probability distribution of the medium access control (MAC) layer packet latency and jitter, on which the quality of the voice over Internet protocol (VoIP) calls is dependent. From the proposed analytic model, we can estimate the available number of nodes determining the system performance, in order to satisfy user demands on the latency and jitter.

Interconnection Issues in CPS

2015 ◽  
pp. 61-75
Keyword(s):  
Wireless Networks ◽  
Mobile Networks ◽  
Ad Hoc ◽  
Multicast Routing ◽  
Distributed Coordination ◽  
Multicast Communication ◽  
Distributed Coordination Function ◽  
Network Properties ◽  
Hoc Networks ◽  
Coordination Function

This chapter shows the interconnection issues in different wireless networks such as ad hoc networks and sensor networks. It also specifies the need for multicast routing protocols in mobile networks, because these wireless networks are suitable for multicast communication due to its inherent transmission ability. Based on the area to be covered, mechanism used for sensor deployment, and various properties of sensor network properties, different coverage formulations have been suggested. In addition, several constructions reachable areas and their expectations along with an outline of the explanations are described. Though 802.11 planned for organization-based systems, the Distributed Coordination Function (DCF) offered in 802.11 permits mobile networks to communicate with the channel exclusive of the base location. Several performance issues related to IEEE 802.11 are revealed. This chapter identifies the main reasons for performance losses and provides solutions for the scenarios that are specific to certain issues related to CPS.

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.

scholarly journals Enhancing MAC performance of DCF protocol for IEEE 802.11 wireless LANs

2017 ◽  
Vol 68 (1) ◽  
pp. 83-86
Author(s):  
Woo-Yong Choi
Keyword(s):  
Access Control ◽  
Medium Access Control ◽  
Ieee 802.11 ◽  
Wireless Lans ◽  
Medium Access Control Protocol ◽  
Distributed Coordination ◽  
Medium Access ◽  
Distributed Coordination Function ◽  
802.11 Wireless Lans ◽  
Coordination Function

Abstract The DCF (Distributed Coordination Function) is the basic MAC (Medium Access Control) protocol of IEEE 802.11 wireless LANs and compatible with various IEEE 802.11 PHY extensions. The performance of the DCF degrades exponentially as the number of nodes participating in the DCF transmission procedure increases. To deal with this problem, we propose a simple, however efficient modification of the DCF by which the performance of the DCF is greatly enhanced.

scholarly journals A Novel Prioritization Scheme to Improve QoS in IEEE 802.11e Networks

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Navid Tadayon ◽  
Saadan Zokaei ◽  
Elaheh Askari
Keyword(s):  
Ieee 802.11E ◽  
Maintenance Cost ◽  
Distributed Coordination ◽  
Mac Layer ◽  
Distributed Coordination Function ◽  
Wireless Medium ◽  
802.11 Wlan ◽  
Well Differentiated ◽  
Coordination Function ◽  
Prioritization Scheme

IEEE 802.11 WLAN utilizes a distributed function at its MAC layer, namely, DCF to access the wireless medium. Due to its distributed nature, DCF is able to guarantee working stability in a wireless medium while maintaining the assembling and maintenance cost in a low level. However, DCF is inefficient in dealing with real-time traffics due to its incapability on providing QoS. IEEE 802.11e was introduced as a supplementary standard to cope with this problem. This standard introduces an Enhanced Distributed Coordination Function (EDCF) that works based on diff-Serve model and can serve multiple classes of traffics (by using different prioritizations schemes). With the emergence of new time-sensitive applications, EDCF has proved to be yet inefficient in dealing with these kinds of traffics because it could not provide network with well-differentiated QoS. In this study, we propose a novel prioritization scheme to improve QoS level in IEEE 802.11e network. In this scheme, we replace Uniform PDF with Gamma PDF, which has salient differentiating properties. We investigate the suitability and superiority of this scheme on furnishing network with well-differentiated QoS using probabilistic analysis. We strengthen our claims by extensive simulation runs.

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.

Sign in / Sign up

Export Citation Format

Share Document