Adaptive Contention Window Design Using Deep Q-Learning

Mobile ad hoc networks (MANETs) consist of self-configured mobile wireless nodes capable of communicating with each other without any fixed infrastructure or centralized administration using the medium radio. Wireless technology is based on standard IEEE.802.11. The IEEE 802.11 Distributed Coordination Function (DCF) MAC layer uses the Binary Exponential Backoff (BEB) algorithm to deal with wireless network collisions. BEB is considered effective in reducing the probability of collisions but at the expense of numerous network performance measures, such as throughput and packets delivery ratio, mainly in high traffic load. Deep Reinforcement Learning (DRL) is a DL technique in which an agent can achieve a goal by interacting with the environment. In this paper, using one of the DRL models, we propose Q-learning (QL) to optimize MAC protocols' performance based on the contention window (CW) in MANETs. The intelligent proposed MISQ takes into account the number of packets to be transmitted and the collisions committed by each station to select the appropriate contention window. The performance of the proposed mechanism is evaluated by using in-depth simulations. The outputs indicate that the intelligent proposal mechanism learns various MANETS environments and optimizes performance over standard MAC protocol. The performance of MISQ is evaluated in various networks with throughput, channel access delay, and packets delivery rate as performance measures.

Download Full-text

Adaptive Contention Window Design to Minimize Synchronous Collisions in 802.11p Networks

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering - Future Intelligent Vehicular Technologies ◽

10.1007/978-3-319-51207-5_4 ◽

2017 ◽

pp. 34-45 ◽

Cited By ~ 1

Author(s):

Syed Adeel Ali Shah ◽

Ejaz Ahmed ◽

Iftikhar Ahmad ◽

Rafidah MD Noor

Keyword(s):

Contention Window ◽

Window Design

Download Full-text

Joint Optimization of Multi-Hop Broadcast Protocol and MAC Protocol in Vehicular Ad Hoc Networks

Sensors ◽

10.3390/s21186092 ◽

2021 ◽

Vol 21 (18) ◽

pp. 6092

Author(s):

Zhonghui Pei ◽

Xiaojun Wang ◽

Zhen Lei ◽

Hongjiang Zheng ◽

Luyao Du ◽

...

Keyword(s):

Ad Hoc Networks ◽

Vehicular Ad Hoc Networks ◽

Ad Hoc ◽

Mac Protocol ◽

Contention Window ◽

Collision Probability ◽

Q Learning ◽

Hoc Networks ◽

The Impact ◽

Broadcast Protocol

Beacon messages and emergency messages in vehicular ad hoc networks (VANETs) require a lower delay and higher reliability. The optimal MAC protocol can effectively reduce data collision in VANETs communication, thus minimizing delay and improving reliability. In this paper, we propose a Q-learning MAC protocol based on detecting the number of two-hop neighbors. The number of two-hop neighbors in highway scenarios is calculated with very little overhead using the beacon messages and neighbor locations to reduce the impact of hidden nodes. Vehicle nodes are regarded as agents, using Q-learning and beacon messages to train the near-optimal contention window value of the MAC layer under different vehicle densities to reduce the collision probability of beacon messages. Furthermore, based on the contention window value after training, a multi-hop broadcast protocol combined with contention window adjustment for emergency messages in highway scenarios is proposed to reduce forwarding delay and improve forwarding reliability. We use the trained contention window value and the state information of neighboring vehicles to assign an appropriate forwarding waiting time to the forwarding node. Simulation experiments are conducted to evaluate the proposed MAC protocol and multi-hop broadcast protocol and compare them with other related protocols. The results show that our proposed protocols outperform the other related protocols on several different evaluation metrics.

Download Full-text

Window design for a professional workstation in the office environment

PsycEXTRA Dataset ◽

10.1037/e574212012-005 ◽

1984 ◽

Author(s):

J. Thomas Murray ◽

Markku T. Hakkinen ◽

James D. Mackraz

Keyword(s):

Office Environment ◽

Window Design

Download Full-text

Review of the Current State and Future Development in Standardizing Natural Lighting in Interiors

Light & Engineering ◽

10.33383/2018-080 ◽

2018 ◽

pp. 5-26 ◽

Cited By ~ 3

Author(s):

Stanislav Darula

Keyword(s):

Human Life ◽

Natural Light ◽

Artificial Lighting ◽

Computer Tools ◽

Natural Lighting ◽

Current State ◽

Minimum Requirements ◽

Life On Earth ◽

Window Design

Three elements mainly wind, water and sun seemed to determine in ancient ages the basic phenomena of life on Earth. Architectural history documented the importance of sun influence on urban and building construction already in layouts of Mesopotamian and Greek houses. Not only sun radiation but especially daylight played a significant role in the creation of indoor environment. Later, in the 20th century, a search of interaction between human life in buildings and natural conditions were studied considering wellbeing and energy conscious design recently using computer tools in complex research and more detail interdisciplinary solutions. At the same time the restricted daytime availability of natural light was supplemented by more efficient and continually cheaper artificial lighting of interiors. There are two main approaches to standardize the design and evaluation of indoor visual environment. The first is based on the determination of the minimum requirements respecting human health and visibility needs in all activities while the second emphasizes the behaviour and comfort of occupants in buildings considering yeararound natural changes of physical quantities like light, temperature, noise and energy consumption. The new current standardization basis for daylight evaluation and window design criteria stimulate the study of methodology principles that historically were based on the overcast type of sky luminance pattern avoiding yearly availability of sky illuminance levels. New trends to base the daylight standardization on yearly or longterm availability of daylight are using the averages or median sky illuminance levels to characterise local climatological conditions. This paper offers the review and discussion about the principles of the natural light standardization with a short introduction to the history and current state, with a trial to focus on the possible development of lighting engineering and its standards in future.

Download Full-text