Browsing by Author "Ye, SR"

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A fair scheduling algorithm with traffic classification for wireless networks
(2005-06-16)
Wang, YC
;
Ye, SR
;
Tseng, YC
;
資訊工程學系
;
Department of Computer Science
Wireless channels are characterized by more serious bursty and location-dependent errors. Many packet scheduling algorithms have been proposed for wireless networks to guarantee fairness and delay bounds. However, most existing schemes do not consider the difference of traffic natures among packet flows. This will cause the delay-weight coupling problem. In particular, serious queuing delays may be incurred for real-time flows. To resolve this problem, we propose a traffic-dependent wireless fair queuing (TD-FQ) algorithm that takes traffic types of flows into consideration when scheduling packets. The proposed TD-FQ algorithm not only alleviates queuing delay of real-time flows, but also guarantees bounded delays and fairness for all flows. (c) 2004 Elsevier B.V. All rights reserved.
A jamming-based MAC protocol for wireless multihop ad hoc networks
(2003)
Ye, SR
;
Wang, YC
;
Tseng, YC
;
資訊工程學系
;
Department of Computer Science
One critical issue in multihop ad hoc networks is the medium access control (MAC). The IEEE 802.11 MAC protocol is originally designed for fully connected, one-hop ad hoc networks but not for multihop ad hoc networks. In addition to the well known hidden-terminal problem, we found that IEEE 802.11 also suffers from an erroneous reservation problem which occurs when RTS-CTS exchange fails but the channel is incorrectly reserved. In this paper, we propose a jamming-based MAC (JMAC) protocol that is not only free from both hidden-terminal and the erroneous reservation problems but also allows more concurrent transmission/reception activities for stations within each other's transmission range. The idea behind the JMAC is to separate source stations' traffic from destination stations' traffic into different channels (i.e., dividing the shared medium into two channels), and explicitly signal the channel status by jamming the channels. Simulation results show that the JMAC can provide higher channel utilization when system is in high traffic load and the frame size is medium or large.
A jamming-based MAC protocol to improve the performance of wireless multihop ad-hoc networks
(2004-02-01)
Ye, SR
;
Wang, YC
;
Tseng, YC
;
資訊工程學系
;
Department of Computer Science
One critical issue in multihop ad-hoc networks is the medium access control (MAC). The IEEE 802.11 MAC protocol is originally designed for fully connected, one-hop ad-hoc networks but not for multihop ad-hoc networks. In addition to the well known hidden-terminal problem, we found that IEEE 802.11 also suffers from an erroneous reservation problem which occurs when RTS-CTS exchange fails but the channel is incorrectly reserved. In this paper, we propose a jamming-based MAC (JMAC) protocol that is not only free from both the hidden-terminal and the erroneous reservation problems but also allows more concurrent transmission/receipt activities for stations within each other's transmission range. The idea behind the JMAC is to separate source stations' traffic from destination stations' traffic into different channels (i.e. dividing the shared medium into two channels), and explicitly signal the channel status by jamming the channels. Simulation results show that although the channel division incurs some cost, the advantages of being free from the erroneous reservation and the hidden-terminal problems, and the benefits of more concurrent transmissions will compensate the cost and provide higher channel utilization when data frame size is median or large. Copyright (C) 2004 John Wiley Sons, Ltd.