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Multi-packet reception (MPR) has been recognized as a powerful capacity-enhancement technique for randomaccess wireless local area networks (WLANs). As is common with all random access protocols, the wireless channel is often under-utilized in MPR WLANs. In this paper, we propose a novel multi-round contention random-access protocol to address this problem. This work complements the existing randomaccess...
AP selection problem is one of the major issues in infrastructure WLANs. Recently, many authors in the literatures have proposed a novel AP selection scheme which can provide better performance (e.g. aggregated throughput, load balancing) than RSS-based legacy scheme. However, they have presented the schemes with non-practical assumptions, e.g. they have assumed that adjacent APs are configured with...
Improvement of spatial reuse, channel efficiency and collision avoid are the main approaches to improve the performance of MAC protocol. IEEE 802.11 protocol, which is the standard MAC protocol of Ad Hoc Networks, hardly provides any mechanisms for improving the spatial reuse and channel efficiency. It mitigates channel collision only by employing RTS and CTS frames. In this paper, we propose a novel...
In this paper, we propose a framework to enhance user perceived quality in a multihomed terminal. Based on the observed media independent handover parameters from all the interfaces, the terminal is made aware of the performance of the different access networks and it can intelligently select the interface to send out the data packets. Several schemes, for the purpose of load balancing, are defined...
In this paper, we present a collision-free asynchronous multi-channel access protocol for Ad Hoc wireless networks using a single transceiver. Our protocol, dubbed AMMAC for Asynchronous Multi-channel Medium Access Control, targets low-cost and low-power deployments where nodes are equipped with a single transceiver. Other distinguishing features of AM-MAC include its simplicity and the fact that...
In IEEE 802.11 Distributed Coordination Function (DCF), the multi-rate Basic Service Set (BSS) suffers from the performance anomaly issue, which brings unfairness in terms of channel occupancy time. To solve the issue, this paper presents a rate control scheme for TCP Friendly Rate Control (TFRC) in IEEE 802.11 DCF mode. The proposed scheme controls the sending rate so that each station can use the...
IEEE 802.11 protocol is widely used in Wireless Local Area Networks (WLAN) for its high data transmission rates. The formation flying satellite system has a short inter-satellite distance, which is similar to WLAN. It may be a good choice to apply IEEE 802.11 protocol in inter-satellite communication to increase throughput. However inter-satellite distance is longer than what desired by WLAN, so IEEE...
Flow control scheme for VANET has not been sufficiently studied. In this paper, we consider the unique characteristics in VANET and propose our flow control scheme called flow control with packet living time prediction (FC-PLT). FC-PLT is based on OPET and mainly solves the interflow contention problem by assigning higher priorities to the packets with less packet living time (PLT) defined as the...
We characterize the Nash equilibrium point of the request probability in a network using the Request-to-send / Clear-to-send (RTS/CTS) handshake mechanism for channel reservation, where each node tries to minimize its average power investment selfishly while meeting its average throughput demand over the shared wireless channel to a common base station. The feasible region of throughput demands is...
Cooperative diversity is a transmission technique, where multiple terminals forms a virtual antenna array that realizes spatial diversity gain in a distributed fashion. The concept of cooperation has already been introduced to MAC layer to design MAC protocol. However, it's much different with that at physical layer. In this paper, we present a new MAC protocol based on IEEE 802.11, called C-MAC,...
In conventional IEEE 802.11 medium access control protocol, the distributed coordination function is designed for the wireless stations (WSs) to perform channel contention within the wireless local area networks (WLANs). Packet collision is considered one of the major issues within this type of contention-based scheme, which can severely degrade the network performance for the WLANs. Research work...
Common channel framework (CCF), a multi-channel mechanism proposed in 802.11 s, extends traditional DCF mechanism and is fully compatible with traditional 802.11 WLAN. According to the characteristics of CCF reaching maximum throughput in the state of no assigning common channel to transmit data, a method to improve the performance of CCF is proposed. In one collide field, under the condition of fixed...
In multi-channel wireless network, several nodes can transmit data simultaneously in different channels. Thus the overall network performance can be improved significantly compared to single channel network. Various multi-channel MAC protocols have been proposed to coordinate the usage of multiple channels. However, multi-channel MAC protocols that use dynamic channel selection can cause multi-channel...
In this paper, we discuss some problems related to direct transmissions between QSTAs in an infrastructure 802.11 WLAN with a legacy access point (AP). In the infrastructure mode, collisions of data frames caused by hidden terminals interference can be avoided by the RTS/CTS exchange anticipating the data frames, if and only if all data communications between stations are performed via the AP. The...
The paper presents results from a link capacity measurement study conducted over an IEEE 802.11b/g network with highly stressed radio propagation conditions in a football stadium. Existing capacity studies for IEEE 802.11 networks have considered either stationary or statistical multipath fading channel conditions. In an environment with a high density of people and movement such as in a football...
In multi-rate IEEE 802.11 wireless LAN, when multiple stations transmit frames at different data rates, the basic service set (BSS) suffers from "performance anomaly" problem. In this paper, to solve this issue, we propose a TCP rate control scheme for IEEE 802.11 DCF mode. In the proposed scheme, a TCP sender controls its maximum window size based on the throughput estimated at the TCP...
Mobile Ad hoc networks typically use a common transmission power approach for the discovery of routes and the transmission of data packets. In this paper we present PCQoS, a power-controlled QoS scheme for wireless ad hoc networks which builds QoS mechanisms for specific applications that wish to tradeoff better QoS performance for sub-optimal paths. PCQoS allows selected flows to modify their transmit...
The physical rate adaptation in 802.11 is a deeply investigated, though still open issue. Since 802.11 uses the random access distributed coordination function (DCF) mechanism to access the medium, collisions can occur when two or more stations want to transmit data simultaneously. The challenge of rate adaptation schemes is to adapt the physical transmission rate based on channel-related losses,...
In this paper, we study the cross-layer (between MAC and PHY) design problem for IEEE 802.11 wireless networks. It is focused on the design of the optimal length of the frame body. The following results are obtained: 1) The optimal length of the frame body in logarithmic scale, expressed as log Lf,opt, can be coarsely approximated by a linear function of the signal-to-noise power ratio (SNR) Eb/N0...
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