scholarly journals StegoFrameOrder—MAC Layer Covert Network Channel for Wireless IEEE 802.11 Networks

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6268
Author(s):  
Krzysztof Sawicki ◽  
Grzegorz Bieszczad ◽  
Zbigniew Piotrowski
Keyword(s):  
Ieee 802.11 ◽  
Radio Channel ◽  
Covert Channel ◽  
Distributed Coordination ◽  
Medium Access ◽  
Deterministic Algorithms ◽  
802.11 Networks ◽  
Ieee 802.11 Networks ◽  
Network Channel ◽  
Coordination Function

The proposed StegoFrameOrder (SFO) method enables the transmission of covert data in wireless computer networks exploiting non-deterministic algorithms of medium access (such as the distributed coordination function), especially in IEEE 802.11 networks. Such a covert channel enables the possibility of leaking crucial information outside secured network in a manner that is difficult to detect. The SFO method embeds hidden bits of information in the relative order of frames transmitted by wireless terminals operating on the same radio channel. The paper presents an idea of this covert channel, its implementation, and possible variants. The paper also discusses implementing the SFO method in a real environment and the experiments performed in the real-world scenario.

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.

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.

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 Hybrid MAC protocol for IEEE 802.11 wireless LANs with hidden node problem

2018 ◽  
Vol 69 (4) ◽  
pp. 323-325
Author(s):  
Woo-Yong Choi
Keyword(s):  
Ieee 802.11 ◽  
Mac Protocol ◽  
Wireless Lans ◽  
Distributed Coordination ◽  
Medium Access Control Protocols ◽  
Medium Access ◽  
Hidden Node ◽  
802.11 Wireless Lans ◽  
Coordination Function ◽  
Node Problem

Abstract Combining the IEEE 802.11 basic MAC (medium access control) protocols, which are the DCF (distributed coordination function) and the PCF (point coordination function), we propose a hybrid MAC protocol to improve the performance of IEEE 802.11 wireless LANs and mitigate the hidden node problem.

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 Improving WLAN Quality of Services (Qos) Using Opnet

2016 ◽  
Vol 9 (3) ◽  
pp. 204-211
Author(s):  
Ishwar Baidari ◽  
S. P. Sajjan ◽  
Ajeet Singh
Keyword(s):  
Ieee 802.11 ◽  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks ◽  
Ieee 802.11E ◽  
Distributed Coordination ◽  
Medium Access ◽  
Access Delay ◽  
Coordination Function

Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. With the increasing demand and penetration of wireless services, users of wireless networks now expect Quality of Service (QoS) and performance comparable to what is available from fixed networks. Providing QoS requirements like good throughput and minimum access delay are challenging tasks with regard to 802.11 WLAN protocols and Medium Access Control (MAC) functions. This research is done to study, the presently implemented schemes (the Point Coordination Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordination Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11), solves these issues and what can be done to improve them further. The metrics used were Throughput, Data Drop, Retransmission and Medium Access Delay, to analyze the performance of various MAC protocols in providing QoS to users of WLAN. Two scenarios, with same Physical and MAC parameters, one implementing the DCF and other EDCF, were created in the network simulation tool (OPNET MODELER) to obtain the results. The results showed that the performance of EDCF was better in providing QoS for real-time interactive services (like video conferencing) as compared to DCF, because of its ability to differentiate and prioritize various services. Index Terms - Wireless local area networks (WLANs),

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