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Radio-On-Demand Networks (ROD) has been proposed in order to improve energy-efficiency of WiFi device, which offers wireless access in an on-demand manner. Each WiFi device in ROD is equipped with a low-power wake-up receiver, which detects the length of wireless LAN frames through envelope detection and on-off-keying (OOK) processing. A STA, upon communications demands, transmits a wake-up signal...
MPTCP is a promising transport technique to boost throughput of wireless multi-homed device by supporting multiple concurrent transmissions through heterogeneous wireless interfaces. As the number of concurrent subflows increase, MPTCP can achieve a linearly increasing throughput performance, but it is unclear how much improvement in the end-to-end delay performance can be attained from additional...
Recently, much effort has been made for implementation of back-pressure scheduling in wireless networks. In this paper, we explore the implementation of back-pressure-based forwarding in wireless sensor networks. For this purpose, we propose Gradient-pressure, a practical Gradient-assisted anycast-based back-pressure framework for wireless sensor networks. Gradient-pressure introduces gradient information...
Community Wireless Networks can be a way to make “Internet access for everyone” possible, by sharing a broadband Internet connection via WLAN. The underlying idea is to freely provide network access to anybody in the vicinity of the wireless access point via a Lower-than-Best-Effort (LBE) service, such that non-paying users interfere as little as possible with the “regular” Internet usage. Such a...
This demo presents a novel multirate multicast scheme for video delivery to wireless users. We demonstrate an adaptive scheme that combines differential backlog scheduling and intelligent packet dropping, both based on local information. An important feature of this scheme is that it does not require centralized calculations. We focus on 802.11 mesh networks and we show that our solution copes efficiently...
Spatial diversity for wireless transmission requires more than one antenna at the transmitter. However, mobile devices are usually limited by size, so installation of multiple antennas increases the hardware complexity significantly. Due to the omnidirectional nature of wireless signal, a data transmission between a source node and a destination node can be overheard by many other neighbor nodes....
This paper presents a cooperation-based retransmission mechanism for IEEE 802.11 networks called Forwarding By Retransmission (FBR). This mechanism aims at reducing the mean number of retransmissions in an infrastructure network, or it can be used to forward frames in a small ad hoc network. FBR enables any node that received a frame to participate in the retransmission process, as long as it has...
By using covert channels, a malicious entity can hide messages within regular traffic and can thereby circumvent security mechanisms. This same method of obfuscation can be used by legitimate users to transmit messages over hostile networks. A promising area for covert channels is wireless networks employing carrier sense multiple access with collision avoidance (CSMA/CA) (e.g., 802.11 networks)....
This paper presents a series of labs in where the performance of practical WLAN technology is evaluated by using PCATTCP software. The experiments can be summarized as follows: Measurement of the throughput as a function of the number of users and network configuration, offered load (sharing efficiency/ fairness). Comparison between the throughput of TCP protocol, and the throughput of UDP Protocol...
Rate adaptation is one of the key factors to improve the performance of the link layer of IEEE 802.11 WLAN. Yet most of the existing rate adaptation policies and algorithms do not consider the effect of the losses due to collisions. To mitigate the effect of collisions, a rate adaptation scheme based on the receiver's SNR is proposed in this paper. It reflects the link condition correctly even when...
In order to reduce energy wastefully consumed by access points (APs) in wireless LAN (WLAN), Radio-On-Demand (ROD) WLAN has been proposed, which offers wireless access only when and where it is needed in an on-demand manner. Each AP in ROD is equipped with a wake-up receiver, which transits a state of AP from sleep to active by receiving a wake-up signal from a station (STA). However, if there are...
Most vehicular ad hoc networks use sender-centric carrier sensing where a sender determines the transmission timing through channel assessment. However, sender-centric carrier sensing suffers from both exposed and hidden terminal problems even with physical and virtual carrier sensing. In this paper, we propose a new receiver-centric carrier sense (RCS) technique where a receiver triggers packet transmissions...
We propose a Cooperative Opportunistic Automatic Repeat ReQuest (CoARQ) scheme to solve the HOL-blocking problem in infrastructure IEEE 802.11 WLANs. HOL blocking occurs when the head-of-the-line packet at the Access Point (AP) queue blocks the transmission of packets to other destinations resulting in severe throughput degradation. When the AP transmits a packet to a mobile station (STA), some of...
A wireless ad hoc network is typically Constrained by battery power, and hence, it is important to conserve battery power in order to keep the network alive for a long time. We consider a wireless network consisting of an access point (AP) and a wireless node, which is limited by energy, and we seek scheduling algorithms that conserve battery power at the wireless node. Since the packet arrivals are...
The metabolic disorder which entails the absent or reduced control of blood glucose in the body by means of insulin dependence (Type 1) or intolerance (Type 2) affected more than 366 million people in 2011. This represents an increase of 28% new cases in one year. Diabetes Mellitus has become the most common chronic diseases in nearly all countries, and continues to increase in numbers and significance,...
Wireless communication systems are expected to operate reliably in the ISM-Bands (Industrial, Scientific, and Medical) even in presence of noise and EMI [1]. The receiver's input circuit, being attached to an antenna is a point of vantage for EMI to couple into the system and to distort the wanted signal. Neither shielding nor filtering effectively protects the receiver from being overdriven by front...
While there has been extensive theoretical work on sophisticated joint resource allocation algorithms for wireless networks, their applicability to WiFi (IEEE 802.11) networks is very limited. One of the main reasons is the limitations in changing MAC parameters in current driver implementations. To this end, in this work, we developed a general cross-layer communication interface in the Linux kernel...
Exposed terminals play a crucial role in the throughput of a wireless ad-hoc network. The 802.11 MAC protocol introduces no methods for decreasing the amount of the terminals exposed to the transmission of the CTS message by the receiver. This paper proposes a new MAC protocol, which by using power capturing mechanisms, decreases the amount of such terminals. This allows for the better utilization...
This paper studies how the spectrum regulation could change in the future open spectrum communication systems. Due to their huge success in short-range communication systems (WiFi, Zigbee, …), broader area telecommunication providers might mimic the open spectrum philosophy to their systems. Nevertheless, current wireless open spectrum systems are not designed for wide areas and they do not provide...
In IEEE 802.11 WLANs, a fixed low transmission rate is used for multicast transmissions regardless of channel conditions of receivers. This may lead to inefficient use of wireless channel, especially when access point (AP) has both unicast and multicast data frames in the transmission queue. In this paper, we propose a dual queue based rate selecting schedule scheme for efficient use of wireless channel...
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