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The problem of network coding over a multiple-access channel (MAC) is considered in this paper. Lattice strategies of encoding indexes of messages are proposed, ensuring that if the sum of any two lattice points is another point over a finite field, then the sum of the two indexes mapped to these two points is equal to the index mapped to another point. In this way, the interference caused by other...
Relays can improve wireless links by providing an extra path to the direct path which together form a virtual multiple antenna system. Network Coded-Distributive Antenna System (NC-DAS) and Plain-Distributive Antenna System (PDAS) are examples of realizations of such scenario. Although the asymptotic diversity gain for both the schemes is comparable, the network coded scheme can further take advantage...
This paper analyzes a cooperative diversity scheme in which multiple (i.e., more than two) source nodes cooperate to deliver their packets to a common destination. To obtain spatial diversity, the source nodes form a partnership that enables each source node to transmit its own packets while relaying those of its partners. Instead of time-multiplexing the codewords for local packets and relay packets...
This paper deals with the evaluation of the end-to-end packet delay for a lossy network where network coding is adopted to achieve better performance. Differently from previous published papers on this subject, connection oriented services are assumed, this means that packets have to be in-order received and wait at the receiver buffer till all the previous ones have been correctly delivered. The...
A large number of network applications today allow several users to interact together using the many-to-many service mode. A many-to-many session consists of group of users (we refer to them as members), where each member transmits its traffic to all other members in the same group. We address the problem of designing and provisioning of WDM networks to support many-to-many traffic grooming. Our objective...
Network coding has recently received increasing attention to improve performance and increase capacity in both wired and wireless communication networks. In this paper, we focus on inter-session network coding, where multiple unicast sessions jointly participate in network coding. Wireless links are often unreliable because of varying channel conditions. We consider multi-hop unicast sessions over...
Network coding is a promising technology that can effectively improve the efficiency and capacity of multihop wireless networks by exploiting the broadcast nature of the wireless medium. However, current packet routing schemes do not take advantage of the network coding, and the benefits of network coding have not been fully utilized. To improve the performance gain of network coding, in this paper,...
In this work, we introduce convolutional codes for network-error correction in the context of coherent network coding. We give a construction of convolutional codes that correct a given set of error patterns, as long as consecutive errors are separated by a certain interval. We also give some bounds on the field size and the number of errors that can get corrected in a certain interval. Compared to...
While original network coding is proposed over the data link layer, recent work suggests that it can also be implemented on the physical layer. In fact it is more natural for wireless networks because of its omnidirectional transmission. In this paper, we investigate the symbol-error-rate (SER) for binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK), but the approaches can be...
Average and outage capacities for nonidentical two-user opportunistic scheduling for wireless network coding (OWNC) are derived in this paper. Nonidentical user case represents a more realistic scenario in which two users have different average signal-to-noise ratio (SNR). Our derived analytical results corroborate with the simulation results in the performance evaluation of OWNC. Insight on the performance...
It has been proved that wireless network coding can increase the throughput of multi-access system and bidirectional system by taking the advantage of the broadcast nature of electromagnetic waves. In this paper, we introduce the wireless network coding into cooperative multicast system. We establish a basic 2-source and 2-destination cooperative system model with arbitrary number of relays (2-N-2...
We consider the uplink of two mobile stations with the help of one common relay. Recently, joint network-channel coding based on LDPC codes was proposed for this setup where the channel codes at the mobile stations and the network code at the relay form one distributed LDPC code. This approach allows to gain diversity with a higher rate compared to a relay system without network coding. We propose...
We propose a precoding strategy which controls amplitude and phase of receiving signals to improve throughput for two-stage bidirectional relaying. We consider the case when the nodes know channel state information (CSI) and can adopt adaptive modulation techniques. We introduce a novel scheme termed adaptive modulation and network coding (AMNC), which jointly optimizes modulations and network coding...
In the anonymous communication mechanisms based on key infrastructure, public key or pre-shared key are widely used to set up relay paths and negotiate shared keys in session. Therefore, these systems always have complicated architecture and high key management cost. However, key infrastructure is hard to deployed in distributed environment. Based on multi-paths network coding, this paper firstly...
We first propose a discrete-time Markov queueing model for a wireless lossy butterfly network which employs opportunistic network coding and dynamic buffer allocation at the bottlenecked relay node. Unlike earlier studies - which assume two or more static buffers at the relay, one for each packet flow - we propose that the relay dynamically allocate buffer space to incoming packets without assuming...
Considering a wireless relay network composed of a source, several relays and a destination where the source transmits data packets to the destination through both direct and relay paths, a multi-timeslots network coding (MTNC) scheme is proposed to combat the lossy nature of wireless channel where the relay nodes with satisfying relay-destination (r - d) channel state firstly perform network coding...
Broadcast is an important primitive in wireless mesh networks (WMNs). Applications like network-wide software update require reliable reception of the content with low-latency and high scalability (i.e., utilizing little bandwidth resource). In reality, the link layer broadcast transmission in WMNs is unreliable, which makes these goals hard to be attained at the same time. In this paper, we consider...
Peer-to-peer networks are a popular means of obtaining large files. Network coding has been shown as an efficient means of sharing large files in a P2P network. With network coding, all file blocks have the same relative importance. This paper presents Deluge, which uses network coding to share large files in a P2P overlay running on a MANET. Peers request file blocks from multiple server nodes and...
The wireless network scenario here is based on N users that communicate one with the others through a central relay node by adopting the Analog Network Coding (ANC) paradigm. In this paper, we propose a communication scheme for ANC able to guaratee the simultaneous transmissions of N ?? 2 interfering terminals using the concept of multiuser processing (i.e., channel estimation and detection). Under...
This paper investigates the performance of practical physical layer network coding (PLNC) schemes for two-way relay channels. We consider a network consisting of two source nodes and a single relay node, which is used to aid communication between the two source nodes. For this scenario, we investigate various transmission schemes, where transmission takes place over two, three or four time slots....
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