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In this paper, a new admission control scheme is presented based on the proportional admission control scheme of the IEEE802.11aa to solve the problems in the 802.11 WLANS. Quality of service (QoS) and throughput are the most significant questions in the 802.11 WLANS especially when the bandwidth is scare. In the Overlapping Basic Service Set (OBSS), we need to face many problems such as the high...
In this paper, we develop a theoretical throughput estimation method for IEEE 802.11 Wireless Local Area Networks (WLANs), which accurately estimates how much throughput each node would achieve in a WLAN where nodes have different characteristics in terms of traffic demands, transmission rates, and packet sizes. The developed method is applicable to various types of topologies of WLANs including hidden...
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...
Efforts are underway in improving power conservation in WLAN devices and thus increasing the duration between recharging the battery. In order to evaluate the performance of new energy saving methods, there is a need for analytical tools. This paper proposes a simple analytical model that provides the average power consumption of a WLAN device. The proposed model is based on Markov models that provide...
In Wireless Local-Area Networks (WLANs), most of the wireless Access Points (APs) work at the full power level. So, the conflicting channels may have a significant and inevitable impact on throughput and transmission delay when the density of the APs is increasing. This paper proposes a power control algorithm, Dynamic Power Control called DPC based on NetFlow. DPC applies a fine tuning idea to get...
IEEE-802.11-based WLAN MAC performance evaluation is of great importance, especially under non-saturated conditions. A new load equation, respect to the non-saturation, is proposed for analysis of the MAC mechanism in this paper. The load equation together with a backoff equation and a transmission equation are sufficient to analyze the MAC performance under non-saturated conditions. In the new load...
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...
In tactical communication systems, WLANs are very popular options due to their high data rate. Motivated by the work of [1], we investigate performance of newly developed signal strength ratio (SSR) based handoff algorithms in tactical communication systems using WLANs. We obtain better performance in terms of number of handoff, packet loss rate and throughput for SSR based handoff algorithms. Performance...
As wireless and mobile technologies are becoming increasingly pervasive, an uninterrupted connectivity in mobile devices is becoming a necessity rather than a luxury. When dealing with challenged networking environments, this necessity becomes harder to achieve in the absence of end-to-end paths from servers to mobiles. One of the main techniques employed to such conditions is to simultaneously use...
In this paper, we propose an analytical model to evaluate the maximum stable throughput of a cognitive IEEE 802.11-based WLAN sharing the downlink band of a cellular network. Our model has been found on an open queueing network which includes both asymmetric and non-saturated aspects of secondary nodes as well as the time-varying nature of the channel due to intermittent primary nodes. By mapping...
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 addresses the problem of MAC performance evaluation of a contemporary IEEE 802.11 WLAN. The network is observed under saturation conditions and the packet transmission probability analysis is conducted with the novel regenerative approach. The proposed model accounts for collision resolution protocol parameters, packet retry limit, coexistence of unicast and broadcast traffic, and heterogeneous...
The goal of this paper is to validate a formulae, originally derived to calculate the throughout upper bound of the IEEE 802.11 networks, over a single Access Point (AP) based WLAN system combined with the IEEE 802.11e EDCA mechanism. In this paper some important assumptions are made to keep the formulae very simple. The most important assumption is that, the AP is providing service to client nodes...
Estimating the throughput of an WiFi connection can be quite complex, even when considering simplified scenarios. Indeed, the varying number of parameters specified in the standards makes it hard to understand their impact in terms of delay and throughput. The main contribution of this work is to present a simple scheme to compute the exact maximum throughput for an IEEE 802.11g network. The proposed...
Recent empirical studies have shown that clients gather together in popular locations, which results in load-imbalance, in a network. One of the key wireless LANs (WLANs) challenges is alleviating the load-imbalance while maximizing the bandwidth utilization. However, the IEEE 802.11-based standard does not provide any formal solution to the load-imbalance problem. Several load-balancing schemes have...
This paper introduces control systems, which regulate tranceivers' packet sizes for prevailing network conditions to achieve maximum throughput and minimum delay for real-time traffic in Wireless Local Area Networks (WLANs). Delay and throughput are very much dependent on the packet size and the connection density. Therefore, the selected input parameters for the controllers are one-way delay and...
In this paper, we address the problem of quantifying the impact of backoff misbehaving nodes in IEEE 802.11 networks. We propose two performance metrics, throughput gain ratio and throughput degradation ratio to quantify the performance gain of misbehaving nodes over legitimate nodes and the performance loss of legitimate nodes due to backoff misbehavior, respectively. We use asymptotic analysis to...
In this paper, we evaluate the saturation throughput for an IEEE 802.11 based wireless network considering capture effect at the receiver, while nodes transmit with random powers. In this respect, we consider a scenario consisting of a specific number of wireless nodes. Then, we derive the transmission as well as collision probabilities with respect to the perfect capture effect. In order to maximize...
IEEE 802.11 distributed coordination function (DCF) medium access control (MAC) does not provide airtime fairness for all stations in a multi-rate scenario as it only provides max-min throughput fairness. This gives rise to the rate anomaly problem where the maximum throughput is limited by the slowest transmitting station. In our paper, we propose airtime fairness in a rate separation IEEE 802.11b...
IEEE 802.11n is a next-generation wireless WLAN standard which can support a MAC data throughput over 100 Mbps. Frame aggregation mechanism is a key feature at the MAC layer which can improve the efficiency of channel utilization. In this paper, we investigate the performance of video transmission over IEEE 802.11n with frame aggregation mechanism. We derive the relationship between Subframe size...
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