scholarly journals The Relation between the Probability of Collision-Free Broadcast Transmission in a Wireless Network and the Stirling Number of the Second Kind

Mathematics ◽  
2018 ◽  
Vol 6 (7) ◽  
pp. 127 ◽  
Author(s):  
Prakash Khomami ◽  
Golnar Khomami ◽  
Fernando Fontan
Keyword(s):  
Analytical Model ◽  
Packet Loss ◽  
Stirling Number ◽  
Delivery Ratio ◽  
Distributed Coordination ◽  
Vehicular Communication ◽  
Medium Access ◽  
Probability Of Collision ◽  
Simulation Results ◽  
Coordination Function

The broadcast performance of the 802.11 wireless protocol depends on several factors. One of the important factor is the number of nodes simultaneously contending for the shared channel. The Medium Access Control (MAC) technique of 802.11 is called the Distributed Coordination Function (DCF). DCF is a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) scheme with binary slotted exponential backoff. A collision is the result of two or more stations transmitting simultaneously. Given the simplicity of the DCF scheme, it was adapted for Dedicated Short Range Communication (DSRC) based vehicular communication. A broadcast mechanism is used to disseminate emergency and safety related messages in a vehicular network. Emergency and safety related messages have a strict end-to-end latency of 100 ms and a Packet Delivery Ratio (PDR) of 90% and above. The PDR can be evaluated through the packet loss probability. The packet loss probabilityPL is given by, PL = 1−(1-Pe)(1-PC), where Pe is the probability of channel error and PC is the probability of collision. Pe depends on several environmental and operating factors and thus cannot be improved. The only way to reduce PL is by reducing PC. Currently, expensive radio hardware are used to measure PL. Several adaptive algorithms are available to reduce PC. In this paper, we establish a closed relation between PC and the Stirling number of the second kind. Simulation results are presented and compared with the analytical model for accuracy. Our simulation results show an accuracy of 99.9% compared with the analytical model. Even on a smaller sample size, our simulation results show an accuracy of 95% and above. Based on our analytical model, vehicles can precisely estimate these real-time requirements with the least expensive hardware available. Also, once the distribution of PC and PL are known, one can precisely determine the distribution of Pe.

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.

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.

Evaluating The Performance for DCF Protocol and EDCA Protocol

2015 ◽  
Vol 72 (5) ◽  
Author(s):  
Ahmed Abu-Khadrah ◽  
Zahriladha Zakaria ◽  
Mohdazlishah Othman
Keyword(s):  
Real Time ◽  
Packet Loss ◽  
Area Network ◽  
Distributed Coordination ◽  
Data Types ◽  
End To End Delay ◽  
Main Challenge ◽  
Qos Parameters ◽  
End To End ◽  
Coordination Function

Nowadays supporting quality of service (QOS) for real time application is the main challenge of the wireless area network. 802.11standards use distributed Coordination Function (DCF) protocol and Enhanced Distributed Channel Access (EDCA) protocol in the MAC layer. DCF protocol has only one queue for different data types, it deals with data depending on the arriving time. There is no priority to serve real time applications faster. However EDCA protocol has four queues and each queue works with specific data type. Voice, video, best effort and background are the different queues in the EDCA protocol. Different parameters and priorities are defined for each queue. The voice queue reserves the highest priority and serves its data first. In this paper QOS parameters are measured for both DCF and EDCA protocol by using OPNET simulation. The QOS parameters must reach the requirements to support QOS. The results show how QOS parameters do not reach the requirements when using DCF protocol. The values of the end to end delay and the packet loss percentage are 0.514second, 19.04% respectively. But, when using EDCA protocol the end to end delay becomes 0.0624 second and the percentage of the packet loss decreases until reach 0.00617%. So the QOS parameters achieve requirements with EDCA protocol and support QOS.

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+.

scholarly journals Avoiding Void Holes and Collisions with Reliable and Interference-Aware Routing in Underwater WSNs

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3038 ◽  
Author(s):  
Nadeem Javaid ◽  
Abdul Majid ◽  
Arshad Sher ◽  
Wazir Khan ◽  
Mohammed Aalsalem
Keyword(s):  
Routing Protocols ◽  
Dynamic Network ◽  
Packet Delivery Ratio ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Underwater Wireless Sensor Networks ◽  
Packet Delivery ◽  
End To End Delay ◽  
Probability Of Collision ◽  
Simulation Results

Sparse node deployment and dynamic network topology in underwater wireless sensor networks (UWSNs) result in void hole problem. In this paper, we present two interference-aware routing protocols for UWSNs (Intar: interference-aware routing; and Re-Intar: reliable and interference-aware routing). In proposed protocols, we use sender based approach to avoid the void hole. The beauty of the proposed schemes is that they not only avoid void hole but also reduce the probability of collision. The proposed Re-Intar also uses one-hop backward transmission at the source node to further improve the packet delivery ratio of the network. Simulation results verify the effectiveness of the proposed schemes in terms of end-to-end delay, packet delivery ratio and energy consumption.

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 TSCH Multiple Slotframe Scheduling for Ensuring Timeliness in TS-SWIPT-Enabled IoT Networks

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 48
Author(s):  
Dongwan Kim ◽  
Jung-Hyok Kwon ◽  
Eui-Jik Kim
Keyword(s):  
Mac Protocol ◽  
Access Point ◽  
Energy Utilization ◽  
Distributed Coordination ◽  
Medium Access ◽  
Sensor Device ◽  
Channel Hopping ◽  
Transmission Period ◽  
A Cell ◽  
Coordination Function

This paper presents a time-slotted channel hopping (TSCH) multiple slotframe scheduling (TMSS) protocol to ensure the timeliness of energy harvesting and data transmission for sensor devices with different transmission periods in Internet of Things (IoT) networks enabled with time-switching simultaneous wireless information and power transfer (TS-SWIPT). The TMSS uses a modified three-step 6P transaction to allocate power and data cells within the slotframe. The sensor device sets the slotframe length equal to the transmission period and estimates the number of power and data cells for allocation in the configured slotframe and requests cell allocation to the hybrid access point (HAP). Upon request from a sensor device, the HAP executes a cell-overlapping prevention (COP) algorithm to resolve the cell-overlapping problem and responds to the sensor device with a candidate cell list. Upon receiving the response from HAP, the sensor device determines its power and data cells by referring to the cell list. We conducted experimental simulations and compared the TMSS performance to that of the legacy TSCH medium access control (MAC) with a single slotframe and the harvest-then-transmit-based modified enhanced distributed coordination function (EDCF) MAC protocol (HE-MAC). The results showed that TMSS outperforms legacy TSCH MAC and HE-MAC in terms of delay, effective throughput and energy utilization.

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.

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