In this paper, a novel dynamic contention window control scheme is presented to improve the performance and energy efficiency of IEEE 802.11-based CSMA/CA DCF wireless networks operating in ad-hoc mode. The number of competing nodes in physical carrier sense systems has a major influence on the probability of collisions and a subsequent impact on DCF performance and on the energy consumed. A ne...

Wireless Local Area Networks (WLANs) are becoming a popular way of networking computer equipments in the home and office. In order to support differentiated Quality-ofService (QoS) in WLANs, the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) protocol allocates multiple Access Categories (ACs) with different priorities, inter-frame spaces, and contention window sizes. This paper present...

The data rates of wireless networks are getting faster and faster. With this trend, IEEE 802.11a, published in 1999 to provide faster data transmission rates, is one of the strongly considered next generation wireless LAN standards. It uses CSMA/CA as the medium access control protocol and OFDM as the physical layer technology. In this paper, to enhance the throughput performance of CSMA/CA pro...

The enhanced parameters tuning (EPT) algorithm is applied to adjust the parameters of 802.11e, i.e. arbitration inter frame space (AIFS), Contention window minimum (CWmin) and Contention window maximum (CWmax). The EPT tuning algorithm is proposed with the simple and effective adjustment in the priority combinations strategy to achieve the high quality of service (QoS). The internal competition...

Wireless sensor networks (WSNs) have been extensively applied in many domains such as smart homes and Internet of Things (IoT). As part of WSNs’ communication protocols, back-off mechanisms play an essential role in the deployment of wireless channels for network nodes and have been at the core of ensuring effective communication. The performance of many back-off algorithms is excellent in ligh...

The number of portable electronic devices capable of maintaining wireless communications increases day by day. Such mobile nodes may easily self-configure to form a Mobile Ad Hoc Network (MANET) without the help of any established infrastructure. As the number of mobile devices grows, the demand of multimedia services such as video-streaming from these networks is foreseen to increase as well. ...

The back-off algorithm is the key point that directly affects the message transmission delay, during the design of the MAC layer of the vehicular ad hoc network communication protocol. However, thanks to the back-off time is inversely proportional to the seizing channel ability of the nodes, the unreasonable choice of the contention window usually leads to the nodes “starvation”. This paper inv...

In this paper, we propose a new protocol, named DDA (Distributed Delay Allocation), which provides average delay guarantees to real-time multimedia applications in wireless ad hoc networks. By adapting the contention window sizes of IEEE 802.11, DDA schedules packets of flows according to their individual delay requirements. The novelty of DDA is that it imposes no control message overhead on t...

This paper proposes an approach to overcome some limitations of the 802.11e protocol highlighted in recent literature and improve the QoS support provided to realtime industrial traffic. The proposed solution does not change the IEEE 802.11e protocol, but introduces a technique to reduce the number of collisions and therefore to use the channel more efficiently for real-time traffic, especially...

The IEEE 802.11 provides a MAC layer protocol for controlling competition among nodes to access the channel in wireless local area network. Recent works show that this standard has not suitable performances in mobile ad-hoc networks and especially in error prone channels. Many researchers proposed many algorithms to improve this standard like HBCWC (History Based Contention Window Control) sche...