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Phase offset is inevitable in asynchronous physical-layer network coding (PNC) systems, which restricts the accuracy of PNC decoding. To address this issue, this paper proposes a half-blind equalization based on pre-distortion. In the scheme, the intentional phase distortion is pre-brought into the symbols of one user, and then, it is utilized by the relay to equalize the received signals and modify...
We propose the design of a novel coding scheme of unequal-sized packets. Unlike the conventional wisdom that consists of brute-force zero-padding in Random Linear Network Coding (RLNC), we exploit this heterogeneity to shave off this trailing overhead and transmit considerably less coded packets. Thanks to the very basic design, which consists of randomly shifting each original packet then applying...
A wireless ad-hoc network can be made to perform better via a range of approaches. One such approach is network coding, which involves broadcasting of encoded packets and therefore can substantially enhance network capacity whilst preserving the quality of service. The use of routing algorithms that are aware of network coding can help to strengthen the benefits of this approach. In order to gain...
Multipath TCP (MPTCP) is a promising extension of TCP to spread data across several subflows enabling multiple path support. Like TCP, MPTCP suffers from performance degradation when deployed in wireless networks. It tends to interpret random link losses as congestion signals. Yet, the protocol is showcased for handheld devices with multiple radios to enable throughput aggregation and seamless handover...
In this paper, we propose a network coding solution to improve transmission reliability of scalable video coding (SVC) streams over lossy networks. Since scalable video coding produces various levels of quality with variable bitrates, we design a prioritized network coding scheme combining different encoding approaches: generation-based and sliding window based schemes. We carried out a performance...
We propose a new low-density parity-check (LDPC) coded binary physical-layer network coding (PNC) scheme for Gaussian two-way relay channels. In this scheme, we introduce a bit mapper between the LDPC encoder and the modulator, which considers the unequal error protections brought by the high order PSK modulations. We add a new bipartite sub-channel graph consisting of sub-channels and variable nodes...
We propose a new linear physical-layer network coding and information combining scheme for the K-user fading multiple-access relay network (MARN), which consists of K users, one relay and one destination. The relay and the destination are connected via a rate-constraint backhaul link. In the proposed scheme, the K users transmit signals simultaneously. The relay and the destination receive the superimposed...
The recent research studies showed that inter-layered network coding is a promising approach to provide the unequal error protection for scalable video multicast under the channel heterogeneity. The selection of the optimal transmission distribution performed at eNB increases the system performance with the cost of time and computational complexities. In this paper, we propose an optimal transmission...
Coded packet networks allow for proactive injection of redundant packets to compensate for packet loss. Link metrics are usually based on the estimated transmission counter (ETX). This metric is used to determine the expected number of coded packets needed, but does not make guarantees for a specific decoding probability. In this paper we show that relying on the ETX metric leads to a surprisingly...
Orthogonal frequency division multiplexing (OFDM) is the most promising approach to combat the frequency selective fading nature of wide-band wireless channels. On the other hand, complex field network coding (CFNC) scheme offers the advantages of better spectral efficiency and full diversity when utilized in multiuser cooperative communication systems. The efficiency of CFNC scheme in relay based...
In this paper we consider multicomponent network codes for a channel with random linear transformations and packet errors. We present a new code construction, which is a generalization of MZP network codes, and similarly uses rank codes as subcodes. In the new construction we use a greedy algorithm, when selecting the code components. It allows us to increase code cardinality compared with the previously...
This paper presents a smooth way to include Network Coding in the Constrained Application Protocol (CoAP) for large resource transmissions. Devices in the Internet of Things usually communicate using short messages with little data. In some cases, for example, requesting firmware updates, bigger resources need to be transferred. CoAP's recently finalized blockwise transfer scheme can handle large...
Random linear network coding simplifies routing decisions, improves throughput, and increases tolerance against packet loss. A substantial limitation, however, is delay: decoding requires as many independent linear combinations as data blocks. Hierarchical network coding purportedly solves this delay problem. It introduces layers to decode prioritized data blocks early, which may benefit video streaming...
We present results on the performance of a network-coding based method for broadcast file delivery in an ad hoc network consisting of half-duplex packet radios. Our technique allows a receiver to exploit the broadcast nature of the wireless medium by overhearing packets sent by a node that is not necessarily one of the receiver's designated relays. Delivery of the file to the remote destinations is...
Network coding (NC) enables us to mix two or more packets into a single coded packet at relay nodes and improve performances in wireless networks. Intra-session sliding window network coding is used at the source nodes and inter-session network coding is employed at the relay node to combine the recovered source packets of source nodes. In this paper, we investigate the performance of the network-coded...
In contrast to the network coding problem wherein the sinks in a network demand subsets of the source messages, in a network computation problem the sinks demand functions of the source messages. Similarly, in the functional index coding problem, the side information and demands of the clients include disjoint sets of functions of the information messages held by the transmitter instead of disjoint...
We consider problems of two-user secret key generation through an intermediate relay. In the untrusted relay setting, the goal is to establish key agreement between the two users at the highest key rate without leaking information about the key to the relay. We characterize inner and outer bounds to the optimal tradeoff between communication and key rates. The inner bound is based on the scheme which...
Multimedia streaming applications have stringent Quality-of-Service (QoS) requirements. Typically, each packet is associated with packet delivery deadline. We are interested in designing feedback-based adaptive network coding schemes with the aim of minimizing decoding delay and video distortion in wireless broadcasting networks over the packet-erasure channel. In this paper, we first introduce the...
Existing finite field network coding (FFNC) can be applied in networks where all users have the same data rate and can thus use the same modulation type. In most practical scenarios, different users typically have different data rates. With simple changes such as zero-padding and repetition to the data sequences of different users received at relays, it is still possible to employ the existing FFNC...
We realized an all-optical digital physical-layer network coding in Fiber-Wireless networks by employing two SOA-MZI XOR gates. Encoding and decoding operations are demonstrated for 1Gb/s data on 10GHz subcarrier and extended to 60GHz with simulations.
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