3,002 research outputs found
Cooperative Peer-to-Peer Repair for Wireless Multimedia Broadcast
Abstract — This paper explores how to leverage IEEE802.11based cooperative peer-to-peer repair (CPR) to enhance the reliability of wireless multimedia broadcasting. We first formulate the CPR problem and present an algorithm that assumes global state information to optimally schedule CPR transmissions. Based on insights gained from the optimal algorithm, we propose a fully distributed CPR (DCPR) protocol. Simulation results demonstrate that the DCPR protocol can effectively enhance the reliability of wireless broadcast services with a repair latency comparable to that of optimal scheduling. I
Reliable Broadcast to A User Group with Limited Source Transmissions
In order to reduce the number of retransmissions and save power for the
source node, we propose a two-phase coded scheme to achieve reliable broadcast
from the source to a group of users with minimal source transmissions. In the
first phase, the information packets are encoded with batched sparse (BATS)
code, which are then broadcasted by the source node until the file can be
cooperatively decoded by the user group. In the second phase, each user
broadcasts the re-encoded packets to its peers based on their respective
received packets from the first phase, so that the file can be decoded by each
individual user. The performance of the proposed scheme is analyzed and the
rank distribution at the moment of decoding is derived, which is used as input
for designing the optimal BATS code. Simulation results show that the proposed
scheme can reduce the total number of retransmissions compared with the
traditional single-phase broadcast with optimal erasure codes. Furthermore,
since a large number of transmissions are shifted from the source node to the
users, power consumptions at the source node is significantly reduced.Comment: ICC 2015. arXiv admin note: substantial text overlap with
arXiv:1504.0446
Wireless Video Transmission with Over-the-Air Packet Mixing
In this paper, we propose a system for wireless video transmission with a
wireless physical layer (PHY) that supports cooperative forwarding of
interfered/superimposed packets. Our system model considers multiple and
independent unicast transmissions between network nodes while a number of them
serve as relays of the interfered/superimposed signals. For this new PHY the
average transmission rate that each node can achieve is estimated first. Next,
we formulate a utility optimization framework for the video transmission
problem and we show that it can be simplified due to the features of the new
PHY. Simulation results reveal the system operating regions for which
superimposing wireless packets is a better choice than a typical cooperative
PHY.Comment: 2012 Packet Video Worksho
Network coding meets multimedia: a review
While every network node only relays messages in a traditional communication system, the recent network coding (NC) paradigm proposes to implement simple in-network processing with packet combinations in the nodes. NC extends the concept of "encoding" a message beyond source coding (for compression) and channel coding (for protection against errors and losses). It has been shown to increase network throughput compared to traditional networks implementation, to reduce delay and to provide robustness to transmission errors and network dynamics. These features are so appealing for multimedia applications that they have spurred a large research effort towards the development of multimedia-specific NC techniques. This paper reviews the recent work in NC for multimedia applications and focuses on the techniques that fill the gap between NC theory and practical applications. It outlines the benefits of NC and presents the open challenges in this area. The paper initially focuses on multimedia-specific aspects of network coding, in particular delay, in-network error control, and mediaspecific error control. These aspects permit to handle varying network conditions as well as client heterogeneity, which are critical to the design and deployment of multimedia systems. After introducing these general concepts, the paper reviews in detail two applications that lend themselves naturally to NC via the cooperation and broadcast models, namely peer-to-peer multimedia streaming and wireless networkin
Centralized and Cooperative Transmission of Secure Multiple Unicasts using Network Coding
We introduce a method for securely delivering a set of messages to a group of
clients over a broadcast erasure channel where each client is interested in a
distinct message. Each client is able to obtain its own message but not the
others'. In the proposed method the messages are combined together using a
special variant of random linear network coding. Each client is provided with a
private set of decoding coefficients to decode its own message. Our method
provides security for the transmission sessions against computational
brute-force attacks and also weakly security in information theoretic sense. As
the broadcast channel is assumed to be erroneous, the missing coded packets
should be recovered in some way. We consider two different scenarios. In the
first scenario the missing packets are retransmitted by the base station
(centralized). In the second scenario the clients cooperate with each other by
exchanging packets (decentralized). In both scenarios, network coding
techniques are exploited to increase the total throughput. For the case of
centralized retransmissions we provide an analytical approximation for the
throughput performance of instantly decodable network coded (IDNC)
retransmissions as well as numerical experiments. For the decentralized
scenario, we propose a new IDNC based retransmission method where its
performance is evaluated via simulations and analytical approximation.
Application of this method is not limited to our special problem and can be
generalized to a new class of problems introduced in this paper as the
cooperative index coding problem
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