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Power-line communications are becoming a key component in home networking. The dominant MAC protocol for high data-rate power-line communications, IEEE 1901, employs a CSMA/CA mechanism similar to the back off process of 802.11. Existing performance evaluation studies of this protocol assume that the back off processes of the stations are independent (the so-called decoupling assumption). However,...
Backoff algorithm is a technique to reduce packet collisions and to improve throughput efficiency in wireless local area network (WLAN). In this research, we propose a new backoff algorithm which is named Binary Exponential Increment Half Decrement (BEIHD) backoff algorithm. Furthermore, we introduce a new discrete Markov chain model for modeling the performance analysis of wireless local area network...
Based on game theory, a general and compatible modeling process, named by GGMP/CSMA (General Game Modeling Process for CSMA/CA), is proposed. With τ (the probability that a node transmits packet in a slot time) as mixed-strategy of game, and M networks performance parameters as payoff functions of game, GGMP/CSMA constitute M rounds of n-players non-cooperative mixed-strategy game. After playing M...
The Payload Dropping CSMA/CA is a cross-layer modified version of the CSMA/CA protocol that can serve as an alternative to the carrier-sense threshold approach for improving throughput in multi-cell networks when the number of co-channel, interference-limited cells is small. The basic idea behind it is a qualification of each signal during the entire preamble and header stages of its reception, and...
In this paper, we propose a new backoff algorithm for wireless local area networks (WLANs). The proposed algorithm develops by using mathematical optimization function theory on Carrier Sensing Multiple Accesses with Collision Avoidance and Request-to-Send Clear-to-Send protocol (CSMA/CA RTS CTS). A new backoff algorithm is named Contending Stations Backoff Algorithm (CSBA). The performance of CSBA...
Consider a backoff algorithm for medium access in wireless networks where a node chooses with probability 1−q to transmit right away and with probability q to transmit after CW slots, where CW is the maximum value of the contention window. We study a variation of the 802.11 protocol called XVBEB which uses the above backoff scheme and give a theoretical analysis of its saturation throughput. Simulation...
An advanced CSMA/CA (carrier sense multiple access with collision avoidance) system incorporating total precedence transmission of all CA and MAC frames (known as a full-flying synchronous CSMA/v-MCA system in Japan, where v- MCA means a variable multiple CA) was developed to minimize the time wasted for upstream channels. In this system, the CA procedures and the controls of the MAC frame transmission...
Many modern wireless data networks employ Carrier Sense Multiple Access (CSMA) for efficient medium access. The p-persistent CSMA protocol is an analytically tractable version of CSMA that has been used successfully to model practical medium access protocols such as the IEEE 802.11 Distributed Coordination Function (DCF). We present a closed-form expression to characterize the access probabilities...
This paper studies the performance of Non-persistent CSMA/CA protocols with Exponential Backoff scheduling algorithms. A multi-queue single-server system is proposed to model multiple access networks. The input buffer of each access node is modeled as a Geo/G/1 queue, and the service time distribution of head-of-line packets is derived from the Markov chain of underlying scheduling algorithm. The...
A novel dynamic contention window control scheme is presented in this paper 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 is one of the major impact on DCF performance and on the energy consumed. A new approach in presented in this paper is using a cross layer...
Multi-path is a technique to increase the reliability of the internet connection in IP network. The implementation of this technique can be described as a host with two TCP paths work together, when one of them fails the other will back up the connection. Since TCP does not support multi-homing, the right term for this technique is multi-path. The fairness problem arises when multi-path host uses...
This paper investigates the effects of adopting multiple transmission queues in IEEE 802.15.4 to differentiate frame sending priorities for providing QoS (Quality of Service) services. By employing different contention window operational parameters for various traffic classes like IEEE 802.11e, the multi-queue system can send frames of higher priority class more rapidly than those of the lower ones...
This paper studies the performance of Non-persistent CSMA protocols using K-Exponential Backoff collision resolution algorithms. We model it as a multi-queue single-server system with infinite buffer size and consider the service time distribution of Head-of-line packets as a Markov Chain to get the network throughput as well as the stability. The stable region of retransmission factor q is illustrated...
The main concerns of network performance are throughput, end-to-end packet delay and packet loss. A high-performance network is characterized by high throughput, small delay, and low packet loss. A larger transmission radius increases the probability of finding a receiver with large progress, but simultaneously increases the probability of collision with other transmissions. Transmission range and...
In this paper we introduce a new MAC protocol called Continuous Contention-Assisted Transmission (CAT) for wireless Ad-hoc network. This proposed protocol is based on Carrier sense multiple access with collision avoidance (CSMA/CA) but we have modified the ACK packet and re-designed mobile stations behavior so that they could continuously transmit data without contention. Our proposed algorithm tries...
In this paper we address the deployment of cooperation in a cellular CDMA environment. In particular, we consider the use of amplify and forward to increase the maximum number of users that can be assigned to each base station. In our scenario, a certain number of fixed relay stations are positioned within the cell: each of them is assigned a group of mobile terminals, whose transmissions are received...
A novel two group bit loading algorithm is proposed for use in a multicode CDMA transmission method at the physical layer in order to improve an adhoc radio system performance. The proposed algorithm provides better data rates than rates achievable with the current HSDPA type of algorithm. The paper also proposes a MAC layer enhancement for use in an adhoc network to improve the total throughput by...
In wireless ad hoc networks, the performance of the media access control (MAC) protocol has significant impact on the overall network performance. In contention-based MAC protocols, nodespsila access to the shared channel is not synchronized, and they contend for the channel whenever there are packets in their buffers ready to be sent. To reduce self-contention, Fast-Forward Mechanism and Quick Exchange...
A mobile ad hoc network is a network without any infrastructure or service access points. In wireless ad hoc networks, the performance of the media access control (MAC) protocol has significant impact on the overall network performance. In contention-based MAC protocols, nodes' access to the shared channel is not synchronized, and they contend for the channel whenever there are packets in their buffers...
High speed downlink packet access (HSDPA) provides increased user data rate by introducing additional functionalities at the Node B, such as fast packet scheduling based on the instantaneous radio link quality. One of the algorithms that is able to provide this capability is the proportional fair (P-FR) scheduler. In this paper we describe an approximate analysis method for the mean throughput of...
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