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From Instantly Decodable to Random Linear Network Coded Broadcast

IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第11期62卷 3943-3955页

作者： Yu, Mingchao Aboutorab, Neda Sadeghi, Parastoo Australian Natl Univ Res Sch Engn Canberra ACT 0200 Australia

Our primary goal in this paper is to better understand and extend the achievable tradeoffs between the throughput and decoding delay performance of network coded wireless broadcast. To this end, we traverse the performance gap between two linear network coding schemes: random linear network coding (RLNC) and instantly decodable network coding (IDNC). Our approach is to appropriately partition a block of partially received data packets into subgenerations and broadcast them separately using RLNC. Through analyzing the factors that affect the performance of a generic partitioning scheme, we are led to develop a coding framework in which subgenerations are created from IDNC coding sets in an IDNC solution. This coding framework consists of a series of coding schemes, with classic RLNC and IDNC identified as two extreme schemes. We develop two basic partitioning guidelines, including disjoint partitioning and even partitioning. We design various implementations of this coding framework, such as partitioning algorithms and generation scheduling strategies, to further improve its throughput and decoding delay, to manage feedback frequency and coding complexity, or to achieve in-block performance adaption. Their effectiveness is verified through extensive simulations, and their performance is compared with an existing work in the literature.

关键词： Wireless broadcast network coding throughput decoding delay tradeoff

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Adaptive Network Coding for Broadband Wireless Access Networks

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2013年第1期24卷 4-18页

作者： Lin, Hui-Tang Lin, Ying-You Kang, Hung-Jung Natl Cheng Kung Univ Inst Comp & Commun Engn Tainan 701 Taiwan Natl Cheng Kung Univ Dept Elect Engn Tainan 701 Taiwan

Broadband wireless access (BWA) networks, such as LTE and WiMAX, are inherently lossy due to wireless medium unreliability. Although the Hybrid Automatic Repeat reQuest (HARQ) error-control method recovers from packet loss, it has low transmission efficiency and is unsuitable for delay-sensitive applications. Alternatively, network coding techniques improve the throughput of wireless networks, but incur significant overhead and ignore network constraints such as Medium Access Control (MAC) layer transmission opportunities and physical (PHY) layer channel conditions. The present study provides analysis of Random Network Coding (RNC) and Systematic Network Coding (SNC) decoding probabilities. Based on the analytical results, SNC is selected for developing an adaptive network coding scheme designated as Frame-by-frame Adaptive Systematic Network Coding (FASNC). According to network constraints per frame, FASNC dynamically utilizes either Modified Systematic Network Coding (M-SNC) or Mixed Generation Coding (MGC). An analytical model is developed for evaluating the mean decoding delay and mean goodput of the proposed FASNC scheme. The results derived using this model agree with those obtained from computer simulations. Simulations show that FASNC results in both lower decoding delay and reduced buffer requirements compared to MRNC and N-in-1 ReTX, while also yielding higher goodput than HARQ, MRNC, and N-in-1 ReTX.

关键词： Retransmission MAC layer network coding next generation broadband wireless access networks decoding delay decoding probability

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On a simple method for detecting synchronization errors in coded messages

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IEEE TRANSACTIONS ON INFORMATION THEORY 2003年第5期49卷 1355-1363页

作者： Konstantinidis, S Perron, S Wilcox-O'Hearn, LA St Marys Univ Dept Math & Comp Sci Halifax NS B3H 3C3 Canada Univ Toronto Dept Comp Sci Toronto ON M5S 3G4 Canada

We investigate the problem of designing pairs (p, S) of words with the property that, if each word of a coded message is prefixed by p and suffixed by s, the resulting set of coded messages is error detecting with finite delay. We consider (combinatorial) channels permitting any combination of the substitution, insertion, and deletion (SID) error types, and address the cases of both scattered and burst errors. A pair (p, s) with the above property is evaluated in terms of three parameters: redundancy, delay of decoding, and frequency of the detectable errors. In the case of SID channels with burst errors, we provide a complete and explicit characterization of their error-detecting pairs (p, s), which involves the period of the word sp.

关键词： burst errors decoding delay deletion error detection insertion period of word

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Lower bounds on the anticipation of encoders for input-constrained channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2001年第5期47卷 1796-1812页

作者： Ruckenstein, G Roth, RM Technion Israel Inst Technol Dept Comp Sci IL-32000 Haifa Israel

An input-constrained channel S is defined as the set of words generated by a finite labeled directed graph. It is shown that every finite-state encoder with finite anticipation (i,e,, with finite decoding delay) for S can be obtained through state-splitting rounds applied to some deterministic graph presentation of S, followed by a reduction of equivalent states, Furthermore, each splitting round can be restricted to follow a certain prescribed structure. This result, in turn, provides a necessary and sufficient condition on the existence of finite-state encoders for S with a given rate p : q and a given anticipation a. A second condition is derived on the existence of such encoders;this condition is only necessary, but it applies to every deterministic graph presentation of S, Based on these two conditions, lower bounds are derived on the anticipation of finite-state encoders, Those lower bounds improve on previously known bounds and, in particular, they are shown to be tight for the common rates used for the (1, 7)-runlength-limited (RLL) and (2,7)-RLL constraints.

关键词： anticipation constrained systems decoding delay decoding look-ahead finite-state encoders input-constrained channels runlength-limited (RLL) constraints state-splitting algorithm

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Bandwidth reduction of extrinsic information exchange in turbo decoding

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ELECTRONICS LETTERS 2006年第19期42卷 1104-1106页

作者： Muller, O. Baghdadi, A. Jezequel, M. Technopole Brest Iroise Dept Elect GET ENST Bretagne F-29238 Brest France

Besides computations and decoding delay, iterations in turbo decoding imply intensive and random extrinsic information exchange between component decoders. This high data exchange rate needs huge communication and routing resources to support the required bandwidth. Proposed is a novel symbol-based criterion to reduce the extrinsic information bandwidth in turbo decoding. The proposed criterion measures each symbol's contribution to the convergence of the iterative process and inhibits unnecessary extrinsic information exchange according to an appropriate threshold. Simulation results demonstrate a 20-25% mean extrinsic information exchange rate reduction with negligible error-rate degradation. This significant bandwidth reduction can directly alleviate communication and routing architecture.

关键词： turbo decoding telecommunication network routing turbo codes information bandwidth iterative process component decoders communication architecture Codes iterative decoding extrinsic information exchange decoding delay Information theory bandwidth allocation data exchange rate routing architecture bandwidth reduction

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Optimality of Huffman Code in the Class of 1-Bit delay Decodable Codes

IEEE JOURNAL ON SELECTED AREAS IN INFORMATION THEORY

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IEEE JOURNAL ON SELECTED AREAS IN INFORMATION THEORY 2022年第4期3卷 616-625页

作者： Hashimoto, Kengo Iwata, Ken-ichi Univ Fukui Grad Sch Engn Fukui 9108507 Japan

For a given independent and identically distributed (i.i.d.) source, Huffman code achieves the optimal average codeword length in the class of instantaneous codes with a single code table. However, it is known that there exist time-variant encoders, which achieve a shorter average codeword length than the Huffman code, using multiple code tables and allowing at most k-bit decoding delay for k = 2, 3, 4, . . .. On the other hand, it is not known whether there exists a 1-bit delay decodable code, which achieves a shorter average length than the Huffman code. This paper proves that for a given i.i.d. source, a Huffman code achieves the optimal average codeword length in the class of 1-bit delay decodable codes with a finite number of code tables.

关键词： Data compression source coding Huffman code decoding delay

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Low-delay, High-Rate Nonsquare Complex Orthogonal Designs

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第5期58卷 2633-2647页

作者： Das, Smarajit Rajan, B. Sundar Tata Inst Fundamental Res Sch Technol & Comp Sci Bombay 400005 Maharashtra India Indian Inst Sci Dept Elect Commun Engn Bengaluru 560012 India

The maximal rate of a nonsquare complex orthogonal design for transmit antennas is 1/2 + 1/n if is even and 1/2 + 1/n+1 if is odd and the codes have been constructed for all by Liang (2003) and Lu et al. (2005) to achieve this rate. A lower bound on the decoding delay of maximal-rate complex orthogonal designs has been obtained by Adams et al. (2007) and it is observed that Liang's construction achieves the bound on delay for equal to 1 and 3 modulo 4 while Lu et al.'s construction achieves the bound for n = 0, 1, 3 mod 4. For n = 2 mod 4, Adams et al. (2010) have shown that the minimal decoding delay is twice the lower bound, in which case, both Liang's and Lu et al.'s construction achieve the minimum decoding delay. For large value of, it is observed that the rate is close to half and the decoding delay is very large. A class of rate-1/2 codes with low decoding delay for all has been constructed by Tarokh et al. (1999). In this paper, another class of rate-1/2 codes is constructed for all in which case the decoding delay is half the decoding delay of the rate-1/2 codes given by Tarokh et al. This is achieved by giving first a general construction of square real orthogonal designs which includes as special cases the well-known constructions of Adams, Lax, and Phillips and the construction of Geramita and Pullman, and then making use of it to obtain the desired rate-1/2 codes. For the case of nine transmit antennas, the proposed rate-1/2 code is shown to be of minimal delay. The proposed construction results in designs with zero entries which may have high peak-to-average power ratio and it is shown that by appropriate postmultiplication, a design with no zero entry can be obtained with no change in the code parameters.

关键词： decoding delay orthogonal designs (ODs) peak-to-average power ratio (PAPR) space-time codes

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Streaming Codes for Three-Node Relay Networks With Burst Erasures

Streaming Codes for Three-Node Relay Networks With Burst Era...

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IEEE International Symposium on Information Theory (ISIT)

作者： Ramkumar, Vinayak Vajhat, Myna Krishnan, M. Nikhil Tel Aviv Univ Dept Elect Engn Syst Tel Aviv Israel IIT Hyderabad Dept Elect Engn Hyderabad India IIT Palakkad Dept Data Sci Kanjikode India

ISBN: (纸本)9798350382853;9798350382846

We study burst erasure correcting streaming codes for three-node relay networks, where there is a source-relay link and a relay-destination link. These codes guarantee that all message packets are recovered within a delay of tau time slots, given that a single burst erasure of length at most b packets occurs in both links. Leveraging previously known techniques in the streaming code literature, we first provide a simple upper bound on the rate of burst erasure correcting streaming codes for three-node relay networks. Our main result is a coding scheme that achieves rates arbitrarily close to the rate upper bound as message size increases.

关键词： Streaming codes burst erasure relay network decoding delay

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Rapprochement between Instantly Decodable and Random Linear Network Coding

Rapprochement between Instantly Decodable and Random Linear ...

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IEEE International Symposium on Information Theory (ISIT)

作者： Yu, Mingchao Aboutorab, Neda Sadeghi, Parastoo Australian Natl Univ Res Sch Engn Canberra ACT Australia

ISBN: (纸本)9781479904464

In this paper, a new network coding model is proposed to unify instantly decodable network coding (IDNC) and random linear network coding (RLNC), which have been considered to be incompatible in the literature. This model is based on a novel definition of generation, which is built upon optimal IDNC solutions. Under this model, IDNC and RLNC are only two extreme cases with specific generation sizes. Throughput and delay properties of this model, measured by block completion time and packet decoding delay, respectively, are studied, which fill the gap between IDNC and RLNC and thus provide a good understanding on the throughput-delay tradeoff of network coding. An efficient adaptive scheme is then designed, which allows in-block switch among IDNC and different levels of RLNC, so that the system's throughput and delay can be fine-tuned to meet the real-time requirements of the application. Extensive simulations are performed to demonstrate how the proposed generation size interacts with the number of receivers and the channel quality to affect the overall system performance.

关键词： network coding wireless broadcast throughput decoding delay

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Towards Zero Loss for TCP in Wireless Networks

Towards Zero Loss for TCP in Wireless Networks

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28th IEEE International Performance Computing and Communications Conference

作者： Chen, Jing Tan, Wei Liu, Lixiang Hu, Xiaohui Xu, Fanjiang Chinese Acad Sci Natl Key Lab Integrated Informat Syst Technol Inst Software Beijing Peoples R China Beidu Inc Beijing Peoples R China

ISBN: (纸本)9781424457373

We propose a novel dynamic network coding retransmission scheme which can effectively mask packet losses and have a quite low decoding delay. By using network coding, we reduce the retransmission waiting time, and by using the implicit information of seen scheme, we acquire the exact number of packets the receiver needs for decoding packets. As our scheme does not require or estimate the loss rate to send redundancies in a constant rate, it is more practical to be implemented in a real system. Furthermore, we incorporate network coding with a load factor based congestion control algorithm which is easy and efficient to be implemented in practical systems. Simulation results show that our scheme significantly outperforms the previous coding approach in reducing decoding delay without sacrificing throughput. It achieves the near-zero congestion loss and "zero" error loss in wireless networks, can be easily and effectively implemented in the practical system.

关键词： network coding packet loss decoding delay TCP

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