A New Coding Paradigm for the Primitive Relay Channel

We consider the primitive relay channel, where the source sends a message to the relay and to the destination, and the relay helps the communication by transmitting an additional message to the destination via a separate channel. Two well-known coding techniques have been introduced for this setting: decode-and-forward and compress-and-forward. In decode-and-forward, the relay completely decodes the message and sends some information to the destination; in compress-and-forward, the relay does not decode, and it sends a compressed version of the received signal to the destination using Wyner–Ziv coding. In this paper, we present a novel coding paradigm that provides an improved achievable rate for the primitive relay channel. The idea is to combine compress-and-forward and decode-and-forward via a chaining construction. We transmit over pairs of blocks: in the first block, we use compress-and-forward; and, in the second block, we use decode-and-forward. More specifically, in the first block, the relay does not decode, it compresses the received signal via Wyner–Ziv, and it sends only part of the compression to the destination. In the second block, the relay completely decodes the message, it sends some information to the destination, and it also sends the remaining part of the compression coming from the first block. By doing so, we are able to strictly outperform both compress-and-forward and decode-and-forward. Note that the proposed coding scheme can be implemented with polar codes. As such, it has the typical attractive properties of polar coding schemes, namely, quasi-linear encoding and decoding complexity, and error probability that decays at super-polynomial speed. As a running example, we take into account the special case of the erasure relay channel, and we provide a comparison between the rates achievable by our proposed scheme and the existing upper and lower bounds.

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An overview of channel coding for 5G NR cellular communications

APSIPA Transactions on Signal and Information Processing ◽

10.1017/atsip.2019.10 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 7

Author(s):

Jung Hyun Bae ◽

Ahmed Abotabl ◽

Hsien-Ping Lin ◽

Kee-Bong Song ◽

Jungwon Lee

Keyword(s):

Channel Coding ◽

Ldpc Codes ◽

Low Latency ◽

Polar Codes ◽

Coding Scheme ◽

Coding Schemes ◽

Successive Cancellation ◽

New Radio ◽

Key Characteristics ◽

User Data

AbstractA 5G new radio cellular system is characterized by three main usage scenarios of enhanced mobile broadband (eMBB), ultra-reliable and low latency communications (URLLC), and massive machine type communications, which require improved throughput, latency, and reliability compared with a 4G system. This overview paper discusses key characteristics of 5G channel coding schemes which are mainly designed for the eMBB scenario as well as for partial support of the URLLC scenario focusing on low latency. Two capacity-achieving channel coding schemes of low-density parity-check (LDPC) codes and polar codes have been adopted for 5G where the former is for user data and the latter is for control information. As a coding scheme for data, 5G LDPC codes are designed to support high throughput, a variable code rate and length and hybrid automatic repeat request in addition to good error correcting capability. 5G polar codes, as a coding scheme for control, are designed to perform well with short block length while addressing a latency issue of successive cancellation decoding.

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Polar Coding for Confidential Broadcasting

Entropy ◽

10.3390/e22020149 ◽

2020 ◽

Vol 22 (2) ◽

pp. 149

Author(s):

Jaume del Olmo Alòs ◽

Javier Rodríguez Fonollosa

Keyword(s):

Random Variables ◽

Optimal Rate ◽

Broadcast Channel ◽

Polar Codes ◽

Wiretap Channel ◽

Coding Scheme ◽

Polar Coding

A polar coding scheme is proposed for the Wiretap Broadcast Channel with two legitimate receivers and one eavesdropper. We consider a model in which the transmitter wishes to send the same private (non-confidential) message and the same confidential message reliably to two different legitimate receivers, and the confidential message must also be (strongly) secured from the eavesdropper. The coding scheme aims to use the optimal rate of randomness and does not make any assumption regarding the symmetry or degradedness of the channel. This paper extends previous work on polar codes for the wiretap channel by proposing a new chaining construction that allows to reliably and securely send the same confidential message to two different receivers. This construction introduces new dependencies between the random variables involved in the coding scheme that need to be considered in the secrecy analysis.

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Multiple Access-Enabled Relaying with Piece-Wise and Forward NOMA: Rate Optimization under Reliability Constraints

Sensors ◽

10.3390/s21144783 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4783

Author(s):

Farnaz Khodakhah ◽

Aamir Mahmood ◽

Patrik Österberg ◽

Mikael Gidlund

Keyword(s):

Spectrum Sharing ◽

Multiple Access ◽

Cooperative Relaying ◽

Achievable Rate ◽

Second Phase ◽

Relay Channel ◽

Direct Link ◽

Secondary System ◽

Amplify And Forward ◽

Decode And Forward

The increasing proliferation of Internet-of-things (IoT) networks in a given space requires exploring various communication solutions (e.g., cooperative relaying, non-orthogonal multiple access, spectrum sharing) jointly to increase the performance of coexisting IoT systems. However, the design complexity of such a system increases, especially under the constraints of performance targets. In this respect, this paper studies multiple-access enabled relaying by a lower-priority secondary system, which cooperatively relays the incoming information to the primary users and simultaneously transmits its own data. We consider that the direct link between the primary transmitter–receiver pair uses orthogonal multiple access in the first phase. In the second phase, a secondary transmitter adopts a relaying strategy to support the direct link while it uses non-orthogonal multiple access (NOMA) to serve the secondary receiver. As a relaying scheme, we propose a piece-wise and forward (PF) relay protocol, which, depending on the absolute value of the received primary signal, acts similar to decode-and-forward (DF) and amplify-and-forward (AF) schemes in high and low signal-to-noise ratio (SNR), respectively. By doing so, PF achieves the best of these two relaying protocols using the adaptive threshold according to the transmitter-relay channel condition. Under PF-NOMA, first, we find the achievable rate region for primary and secondary receivers, and then we formulate an optimization problem to derive the optimal PF-NOMA time and power fraction that maximize the secondary rate subject to reliability constraints on both the primary and the secondary links. Our simulation results and analysis show that the PF-NOMA outperforms DF-NOMA and AF-NOMA-based relaying techniques in terms of achievable rate regions and rate-guaranteed relay locations.

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A Joint Channel-Network Coding Based on Product Codes for the Multiple-Access Relay Channel

ISRN Communications and Networking ◽

10.5402/2012/837815 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Tafzeel ur Rehman Ahsin ◽

Slimane Ben Slimane

Keyword(s):

Network Coding ◽

Channel Coding ◽

Multiple Access ◽

Relay Channel ◽

Decoding Algorithm ◽

Channel Network ◽

Product Codes ◽

Coding Scheme ◽

Coding Schemes ◽

Joint Channel

The multiple access relay channel with network coding has the potential to achieve diversity and improve coverage of wireless networks. Its network coding scheme provides an extra redundancy that can be used at the receiver to improve the performance of the cooperating users. This paper shows that the combination of channel coding and network coding, in the multiple access relay channel, can be seen as a product code with rows formed by the code-words of the individual channel codes of the users and columns formed by the network coding code-words. This new representation allows the use of any decoding algorithm of product codes at the receiver to decode the information data of the cooperating users. This decoding process is a complete joint channel-network decoding algorithm as it sees the combination of the two coding schemes as a single coding scheme. It also gives the possibility to use network coding schemes more powerful than conventional XOR-based network coding. The obtained results show that the proposed product-based network coding structure can improve the performance of the multiple-access relay channel without reducing its efficiency and allow a very flexible cooperation between the involved users.

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To Code or Not to Code: Maximizing the Achievable Rate Region of Two-Way Decode-and-Forward Multiantenna Relay Channel

IEEE Communications Letters ◽

10.1109/lcomm.2014.2332332 ◽

2014 ◽

Vol 18 (8) ◽

pp. 1303-1306 ◽

Cited By ~ 2

Author(s):

Shaohua Zhao ◽

Wei Chen

Keyword(s):

Achievable Rate ◽

Relay Channel ◽

Decode And Forward ◽

Rate Region

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Decode-and-forward polar coding scheme for receive diversity: a relay partially perfect retransmission for half-duplex wireless relay channels

IET Communications ◽

10.1049/iet-com.2016.0915 ◽

2017 ◽

Vol 11 (2) ◽

pp. 185-191 ◽

Cited By ~ 9

Author(s):

Tamer Soliman ◽

Fengfan Yang ◽

Saqib Ejaz ◽

Amir Almslmany

Keyword(s):

Relay Channels ◽

Decode And Forward ◽

Coding Scheme ◽

Receive Diversity ◽

Polar Coding ◽

Half Duplex ◽

Wireless Relay

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Parameter-Invariant Hierarchical Exclusive Alphabet Design for 2-WRC with HDF Strategy

Acta Polytechnica ◽

10.14311/1245 ◽

2010 ◽

Vol 50 (4) ◽

Author(s):

T. Uřičář

Keyword(s):

Achievable Rate ◽

Geometrical Approach ◽

Relay Channel ◽

Capacity Region ◽

Decode And Forward ◽

Rate Region ◽

Phase Rotation ◽

Capacity Degradation ◽

Proper Design ◽

Exclusive Property

Hierarchical eXclusive Code (HXC) for the Hierarchical Decode and Forward (HDF) strategy in the Wireless 2-Way Relay Channel (2-WRC) has the achievable rate region extended beyond the classical MAC region. Although direct HXC design is in general highly complex, a layered approach to HXC design is a feasible solution. While the outer layer code of the layered HXC can be any state-of-the-art capacity approaching code, the inner layer must be designed in such a way that the exclusive property of hierarchical symbols (received at the relay) will be provided. The simplest case of the inner HXC layer is a simple signal space channel symbol memoryless mapper called Hierarchical eXclusive Alphabet (HXA). The proper design of HXA is important, especially in the case of parametric channels, where channel parametrization (e.g. phase rotation) can violate the exclusive property of hierarchical symbols (as seen by the relay), resulting in significant capacity degradation. In this paper we introduce an example of a geometrical approach to Parameter-Invariant HXA design, and we show that the corresponding hierarchical MAC capacity region extends beyond the classical MAC region, irrespective of the channel pametrization.

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