Search results for "ROUGH"
showing 10 items of 1198 documents
Medium access in WiFi networks: strategies of selfish nodes [Applications Corner]
2009
This article provides a game theoretical analysis of the WiFi MAC protocol to understand the risks or the advantages offered by possible modifications of MAC functionalities implemented at the driver level.
Optimization of the Relay Selection Scheme in Cooperative Retransmission Networks
2011
Cooperative MAC protocol design has attracted much attention recently thanks to the development of relaying techniques. In single-relay C-ARQ, the relay selection scheme cannot work efficiently in a dense network, due to high collision probability among different contending relays. In this paper, the throughput performance impairment from the collision is analysed in a typical network scenario. Thereby, we propose an optimized relay selection scheme aiming at maximizing system throughput by reducing collision probability. The throughput performance enhancement by the proposed optimal relay selection scheme is verified by simulations.
Multi-Antenna Covert Communication With Jamming in the Presence of a Mobile Warden
2021
Covert communication can hide the information transmission process from the warden to prevent adversarial eavesdropping. However, it becomes challenging when the warden can move. In this paper, we propose a covert communication scheme against a mobile warden, which maximizes the connectivity throughput between a multi-antenna transmitter and a full-duplex jamming receiver with the covert outage probability (COP) limit. First, we analyze the monotonicity of the COP to obtain the optimal location the warden can move. Then, under this worst situation, we optimize the transmission rate, the transmit power and the jamming power of covert communication to maximize the connection throughput. This …
Joint routing and per-flow fairness in wireless multihop networks
2008
In wireless multihop networks communication between two end-nodes is carried out by hopping over multiple short wireless links. Traditional CSMA/CA based media access control does not work satisfactory in a multihop scenario, since an intended target of a communication may be subject to mutual interference imposed by concurrent transmissions from nodes which cannot directly sense each other, causing unfair throughput allocation. Although TDMA seems to be a more promising solution, careful transmission scheduling is needed in order to achieve error-free communication and fairness. In our previous work, a TDMA scheduling algorithm has been proposed that schedules the transmissions in a fair m…
AES/FPGA Encryption Module Integration for Satellite Remote Sensing Systems: LST-SW case
2020
Satellite remote sensing embedded systems need to be secure to protect data transmission between satellites and the ground station for any threat can affects the hardware of satellite and interception of data, in addition to unauthorized access to satellite system. This research proposes an approach for a secure integration of FPGA Encryption module based on the iterative looping architecture for remote sensing algorithm and especially for the LST-SW algorithm. The target hardware used in this paper is Virtex-5 XC5VLX50T FPGA from Xilinx. Hardware Description Language was used to design the complete system. The analysis of the proposed designed shows that this implementation can achieved a …
Bluetooth throughput measures for cardiomyocyte extracellular signal telemetry
2006
In this contribution the suitability of the Bluetooth transmission system is analyzed for its application to the realtime transmission of cardiac signals captured by micro-electrode array sensors. The required data rates for this type of cardiac signals are calculated to be 180 kbps for every single micro- electrode. The mean throughput value varies with the selected packet size: for packet sizes less than 1000 bytes the mean throughput is smaller than 180 kbps while for packet sizes greater than 1000 bytes the mean throughput saturates at around 230 kbps. This mean throughput value is guaranteed for over 80% of the time. Compression algorithms running on the sensor array allow the reductio…
Temporal Fairness Provisioning in Multi-Rate Contention-Based 802.11e WLANs
2005
The IEEE 802.11e extensions for QoS support in WLAN define the transmission opportunity (TXOP) concept, in order to limit the channel holding times of the contending stations in the presence of delay-sensitive traffic. We evaluate the use of TXOP for a different purpose: "temporal fairness" provisioning among stations employing different data rates. We show that the equalization of the channel access times allows each station to obtain its throughput basically (1) proportional to its transmission rate, and (2) independent of the transmitted frame length. This also improves the aggregate throughput of the overall WLAN. For a given TXOP limit, i.e., a granted channel access time, a station is…
Energy consumption and optimal relay node placement for cooperative retransmissions
2010
Previous work on cooperative MAC design has shown significant performance improvement in terms of throughput and packet delivery ratio. However, little attention has been paid to extra energy cost at the relay node in order to achieve such benefit. In this paper, we focus on analyzing energy consumption at a relay node in cooperative retransmission networks with mixed Rayleigh and Rician fading channels. Furthermore, optimal relay location is studied with respect to energy efficiency in different scenarios. The simulation and calculation results coincide with each other, both showing the optimal location of the relay node is scenario-dependent and can be obtained under given channel conditi…
An enhanced TCP congestion avoidance scheme and its performance evaluation in high speed satellite networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE." Article also available from publisher: http://dx.doi.org/10.1109/ICICS.2009.5397691 High speed satellite communication networks are emerging as part of the future global wireless communication systems. However, existing transmission control protocols for satellite networks do not provide satisfactory performance over high speed satellite links due to their ine…
The use of rapid onset opioids for breakthrough cancer pain: the challenge of its dosing.
2011
Breakthrough cancer pain (BTcP) has been defined as a transitory increase in pain intensity on a baseline pain of moderate intensity in patients on analgesic treatment regularly administered. This review provides updated information about the use of opioids for the treatment of BTcP, with special emphasis on the use of new rapid onset opioids (ROOs). Due to its slow onset to effect oral opioids cannot be considered an efficacious treatment for BTcP. Parenteral opioids may provide rapid onset of analgesia, but not always available particularly at home. Different technologies have been developed to provide fast pain relief with potent opioid drugs such fentanyl, delivered by non-invasive rout…