IEEE 802.11a Throughput Performance with Hidden Nodes
ABSTRACT Analytic performance of IEEE 802.11 distributed coordination function that takes into account hidden node problem and unsaturated traffic condition is presented for symmetric networks. This enables us to estimate the performance of practical wireless local area networks more accurately. It is shown that the presence of hidden nodes barely affects the network performance in low traffic conditions, but it causes 33% performance loss in moderate traffic scenarios. Analytical results presented in the paper are backed by simulation results.
- SourceAvailable from: Antonios Argyriou[Show abstract] [Hide abstract]
ABSTRACT: In this paper, we present a cross-layer framework for optimizing the performance of opportunistic network coding in wireless multihop networks. The target scenario considers a wireless ad hoc network (WANET) with backlogged nodes and with multiple unicast packet flows. Initially, we focus on modeling the expected network-coded throughput individually for each wireless station as a function of parameters at the lower layers, like the maximum number of link-layer retransmissions and the transmission mode at the physical layer (PHY). Based on this analysis, we develop a network-coding algorithm that opportunistically and locally optimizes the expected information content of individual packet transmissions. To address the problem in a multihop setting, we focus on controlling the air time that is consumed by the resulting transmissions of coded packets. More specifically, we devise a distributed-cooperation algorithm that allows nodes to select the optimal PHY transmission mode by also considering the PHY selection of their neighbors. Nodes use only a partial view of the link contention relationships up to their interference range. Compared with existing works on opportunistic network coding and scheduling in ad hoc networks, our approach can yield significant throughput gains without employing complex link-scheduling algorithms.IEEE Transactions on Vehicular Technology 03/2010; · 2.06 Impact Factor
Conference Paper: Performance Analysis of IEEE 802.11ac DCF with Hidden Nodes[Show abstract] [Hide abstract]
ABSTRACT: Recently, the IEEE 802.11 standard based Wireless Local Area Networks (WLAN) have become more popular and are widely deployed. It is anticipated that WLAN will play an important rule in the future wireless communication systems in order to provide several gigabits data rate. IEEE 802.11ac is one of the ongoing WLAN standard aiming to support very high throughput (VHT) with data rate of up to 6 Gbps below the 6 GHz band. In the development of IEEE 802.11ac standard, several new physical layer (PHY) and medium access control layer (MAC) features are taken into consideration, such as employing wider bandwidth in PHY and incrementing the limits of frame aggregation in MAC. However, due to the newly introduced features, some traditional techniques used in previous standards could face some problems. This paper presents a performance analysis of 802.11ac Distributed Coordination Function (DCF) in presence of hidden nodes in overlapping BSS (OBSS) environment. The effectiveness of DCF in IEEE 802.11ac WLAN when using different primary channels and different frequency bandwidth has also been discussed. Our results indicate that the traditional RTS/CTS handshake mechanism faces shortcomings and needs to be modified in order to support the newly defined 802.11ac amendment.Vehicular Technology Conference (VTC Spring), 2012 IEEE 75th; 01/2012
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ABSTRACT: The emergence of high-density wireless local area network (WLAN) deployments in recent years is a testament to the insatiable demands for wireless broadband services. The increased density of WLAN deployments brings with it the potential of increased capacity, extended coverage, and exciting new applications. However, the corresponding increase in contention and interference can significantly degrade throughputs, unless new challenges in channel assignment are effectively addressed. In this paper, a client-assisted channel assignment scheme that can provide enhanced throughput is proposed. A study on the impact of interference on throughput with multiple access points (APs) is first undertaken using a novel approach that determines the possibility of parallel transmissions. A metric with a good correlation to the throughput, i.e., the number of conflict pairs, is used in the client-assisted minimum conflict pairs (MICPA) scheme. In this scheme, measurements from clients are used to assist the AP in determining the channel with the minimum number of conflict pairs to maximize its expected throughput. Simulation results show that the client-assisted MICPA scheme can provide meaningful throughput improvements over other schemes that only utilize the AP's measurements.IEEE Transactions on Vehicular Technology 10/2011; 60(9):4497 - 4508. · 2.06 Impact Factor