106 research outputs found
Maximum Multipath Routing Throughput in Multirate Wireless Mesh Networks
In this paper, we consider the problem of finding the maximum routing
throughput between any pair of nodes in an arbitrary multirate wireless mesh
network (WMN) using multiple paths. Multipath routing is an efficient technique
to maximize routing throughput in WMN, however maximizing multipath routing
throughput is a NP-complete problem due to the shared medium for
electromagnetic wave transmission in wireless channel, inducing collision-free
scheduling as part of the optimization problem. In this work, we first provide
problem formulation that incorporates collision-free schedule, and then based
on this formulation we design an algorithm with search pruning that jointly
optimizes paths and transmission schedule. Though suboptimal, compared to the
known optimal single path flow, we demonstrate that an efficient multipath
routing scheme can increase the routing throughput by up to 100% for simple
WMNs.Comment: This paper has been accepted for publication in IEEE 80th Vehicular
Technology Conference, VTC-Fall 201
Collision Codes: Decoding Superimposed BPSK Modulated Wireless Transmissions
The introduction of physical layer network coding gives rise to the concept
of turning a collision of transmissions on a wireless channel useful. In the
idea of physical layer network coding, two synchronized simultaneous packet
transmissions are carefully encoded such that the superimposed transmission can
be decoded to produce a packet which is identical to the bitwise binary sum of
the two transmitted packets. This paper explores the decoding of superimposed
transmission resulted by multiple synchronized simultaneous transmissions. We
devise a coding scheme that achieves the identification of individual
transmission from the synchronized superimposed transmission. A mathematical
proof for the existence of such a coding scheme is given
Cooperative Retransmissions Through Collisions
Interference in wireless networks is one of the key capacity-limiting
factors. Recently developed interference-embracing techniques show promising
performance on turning collisions into useful transmissions. However, the
interference-embracing techniques are hard to apply in practical applications
due to their strict requirements. In this paper, we consider utilising the
interference-embracing techniques in a common scenario of two interfering
sender-receiver pairs. By employing opportunistic listening and analog network
coding (ANC), we show that compared to traditional ARQ retransmission, a higher
retransmission throughput can be achieved by allowing two interfering senders
to cooperatively retransmit selected lost packets at the same time. This
simultaneous retransmission is facilitated by a simple handshaking procedure
without introducing additional overhead. Simulation results demonstrate the
superior performance of the proposed cooperative retransmission.Comment: IEEE ICC 2011, Kyoto, Japan. 5 pages, 5 figures, 2 tables. Analog
Network Coding, Retransmission, Access Point, WLAN, interference, collision,
capacity, packet los
An Efficient Network Coding based Retransmission Algorithm for Wireless Multicasts
Retransmission based on packet acknowledgement (ACK/NAK) is a fundamental
error control technique employed in IEEE 802.11-2007 unicast network. However
the 802.11-2007 standard falls short of proposing a reliable MAC-level recovery
protocol for multicast frames. In this paper we propose a latency and bandwidth
efficient coding algorithm based on the principles of network coding for
retransmitting lost packets in a singlehop wireless multicast network and
demonstrate its effectiveness over previously proposed network coding based
retransmission algorithms.Comment: 5 pages, 5 figure
SSthreshless Start: A Sender-Side TCP Intelligence for Long Fat Network
Measurement shows that 85% of TCP flows in the internet are short-lived flows
that stay most of their operation in the TCP startup phase. However, many
previous studies indicate that the traditional TCP Slow Start algorithm does
not perform well, especially in long fat networks. Two obvious problems are
known to impact the Slow Start performance, which are the blind initial setting
of the Slow Start threshold and the aggressive increase of the probing rate
during the startup phase regardless of the buffer sizes along the path. Current
efforts focusing on tuning the Slow Start threshold and/or probing rate during
the startup phase have not been considered very effective, which has prompted
an investigation with a different approach. In this paper, we present a novel
TCP startup method, called threshold-less slow start or SSthreshless Start,
which does not need the Slow Start threshold to operate. Instead, SSthreshless
Start uses the backlog status at bottleneck buffer to adaptively adjust probing
rate which allows better seizing of the available bandwidth. Comparing to the
traditional and other major modified startup methods, our simulation results
show that SSthreshless Start achieves significant performance improvement
during the startup phase. Moreover, SSthreshless Start scales well with a wide
range of buffer size, propagation delay and network bandwidth. Besides, it
shows excellent friendliness when operating simultaneously with the currently
popular TCP NewReno connections.Comment: 25 pages, 10 figures, 7 table
Sizes of Minimum Connected Dominating Sets of a Class of Wireless Sensor Networks
We consider an important performance measure of wireless sensor networks, namely, the least number of nodes, N, required to facilitate routing between any pair of nodes, allowing other nodes to remain in sleep mode in order to conserve energy. We derive the expected value and the distribution of N for single dimensional dense networks
On the Selection of Transmission Range in Underwater Acoustic Sensor Networks
Transmission range plays an important role in the deployment of a practical underwater acoustic sensor network (UWSN), where sensor nodes equipping with only basic functions are deployed at random locations with no particular geometrical arrangements. The selection of the transmission range directly influences the energy efficiency and the network connectivity of such a random network. In this paper, we seek analytical modeling to investigate the tradeoff between the energy efficiency and the network connectivity through the selection of the transmission range. Our formulation offers a design guideline for energy-efficient packet transmission operation given a certain network connectivity requirement
Contextual Multi-Armed Bandit based Beam Allocation in mmWave V2X Communication under Blockage
© 2023, IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This is the accepted manuscript version of a conference paper which has been published in final form at https://doi.org/10.1109/VTC2023-Spring57618.2023.10200248Due to its low latency and high data rates support, mmWave communication has been an important player for vehicular communication. However, this carries some disadvantages such as lower transmission distances and inability to transmit through obstacles. This work presents a Contextual Multi-Armed Bandit Algorithm based beam selection to improve connection stability in next generation communications for vehicular networks. The algorithm, through machine learning (ML), learns about the mobility contexts of the vehicles (location and route) and helps the base station make decisions on which of its beam sectors will provide connection to a vehicle. In addition, the proposed algorithm also smartly extends, via relay vehicles, beam coverage to outage vehicles which are either in NLOS condition due to blockages or not served any available beam. Through a set of experiments on the city map, the effectiveness of the algorithm is demonstrated, and the best possible solution is presented
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