User diversity arises when wireless users experience diverse channel conditions. This paper proposes three opportunistic random access algorithms that favor users with the best channel conditions in channel access. These algorithms operate on the contention mechanism of CSMA/CA and compute the contention window based on channel conditions. In one algorithm, the contention windows of all users s...

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It is well known that one of the critical sources of TCP poor performance in multihop ad hoc networks lies in the TCP window mechanism that controls the amount of traffic sent into the network. In this paper, we propose a novel cross layer solution called “TCP Contention Control” that dynamically adjusts the amount of outstanding data in the network based on the level of contention experienced ...

Massive tremendous amount of miniaturized wireless Internet Things (IoT) devices are widely employed in many fields such as industrial production, social life, public (and defense) security and management human society. The limitation node device's energy capacity is the bottleneck issue these network systems. MAC protocol a key communication for sensor nodes which both rationally saves (an alt...

The standard IEEE 802.11 MAC protocol uses the Binary Exponential Backoff algorithm. The Binary Exponential Backoff makes exponential increments to contention window sizes. This work has studied the effect of choosing a combination between linear, exponential and logarithmic increments to contention windows. Results have shown that choosing the right increment based on network status enhances t...

The IEEE 802.11e standard introduces a system of Access Categories (AC) and differentiated medium access control mechanisms for wireless local area networks. The preferential or deferral treatment of frames is achieved using configurable Arbitration Inter-Frame Spaces (AIFS) and customizable Contention Window (CW) sizes. In this paper we introduce a general algorithm which calculates the probab...

In the IEEE 802.11 standard, network nodes experiencing collisions on the shared medium need a mecha‐ nism that can prevent collisions and improve the throughput. Furthermore, a backoff mechanism is used that uniformly selects a random period of time from the contention window (cw) that is dynamically controlled by the Binary Exponential Backoff (BEB) algorithm. Prior research has proved that t...

Recently, Wireless Sensor Network (WSN) is a fast growing technology, which collects various data for user and provides user with requested information in timely. A sensor network has a Many-to-One communication architecture which each sensor node transmits its sensed data to the sink node. However, most existing sensor network protocols do not consider Many-to-One paradigm and all sensor nodes...

in wireless networks, the sharing channel has limited communication bandwidth. So designing efficient Medium Access Control (MAC) protocol with high performances is a major focus in distributed contention-based MAC protocol research. IEEE 802.11 MAC protocol is the most famous standard in this area. But, this standard has a problem with adopting its backoff range based on channel status. It cau...