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To overhear or not to overhear: a dilemma between network coding gain and energy consumption in multi-hop wireless networks

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WIRELESS NETWORKS 2019年第7期25卷 4097-4113页

作者： Javan, Nastooh Taheri Sabaei, Masoud Dehghan, Mehdi Amirkabir Univ Technol Comp & Informat Technol Engn Dept Tehran Polytech Tehran Iran

Any properly designed network coding technique can result in increased throughput and reliability of multi-hop wireless networks by taking advantage of the broadcast nature of wireless medium. In many inter-flow network coding schemes nodes are encouraged to overhear neighbour's traffic in order to improve coding opportunities at the transmitter nodes. A study of these schemes reveal that some of the overheard packets are not useful for coding operation and thus this forced overhearing increases energy consumption dramatically. In this paper, we formulate network coding aware sleep/wakeup scheduling as a semi Markov decision process (SMDP) that leads to an optimal node operation. In the proposed solution for SMDP, the network nodes learn when to switch off their transceiver in order to conserve energy and when to stay awake to overhear some useful packets. One of the main challenges here is the delay in obtaining reward signals by nodes. We employ a modified reinforcement learning method based on continuous-time Q-learning to overcome this challenge in the learning process. Our simulation results confirm the optimality of the new methodology.

关键词： Wireless multi-hop networks Network coding Energy consumption coding gain SMDP Q-learning

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Synthesis filters design for coding gain in oversampled filter banks

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IEEE SIGNAL PROCESSING LETTERS 2005年第10期12卷 697-700页

作者： Labeau, F McGill Univ Dept Elect & Comp Engn Montreal PQ H3A 2A7 Canada

In this letter, we study the impact of the design freedom brought about by oversampling in perfect reconstruction oversampled filter banks, on the choice of synthesis filters that maximize the coding gain. In particular, based on the expression of the coding gain for the oversampled case, we show the dependency of the coding gain on both analysis and synthesis filters. We explore how the choice of synthesis filters can affect the coding gain, given a fixed set of analysis filters. We show that the para-pseudo-inverse is a good choice for the maximization of the coding gain when the corresponding analysis filters have been optimized for coding gain under critical sampling.

关键词： coding gain date compression filter banks multirate signal processing oversampling

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Performance evaluation of diversity gain and coding gain in coded orthogonal multi-carrier modulation systems

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2004年第3期15卷 201-206页

作者： Fujii, M Itami, M Itoh, K Sci Univ Tokyo Dept Appl Elect Noda Chiba 2788510 Japan

This paper presents a performance evaluation of diversity and coding gains in coded orthogonal multicarrier (MC) modulation systems. Assuming maximum likelihood decoding, we analyze contribution of channel encoding to pairwise error rate (PER) in terms of the Hamming distance between codewords for coded-OFDM systems and coded-OFDM-code division multiplexing (CDM) systems. Moreover, the average bit error rate is upper-bounded using the pairwise error rate and is compared with the results obtained by computer simulations. Copyright (C) 2004 AEI.

关键词： Orthogonal ABER Pairwise Error analysis maximum likelihood decoding Multicarrier modulation Computer Simulation coding gain Diversity methods Hamming distance Performance Evaluation Channel coding

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Inequality on the coding gain of densest lattice packings in successive dimensions

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Designs, Codes, and Cryptography 1998年第3期14卷 207-212页

作者： Banihashemi, Amir H. Khandani, Amir K. Department of Electrical and Computer Engineering University of Toronto Toronto Canada

A lower bound of the form (2n/n+1)1/nγn-1n-1/n is derived on the coding gain γn of the densest n-dimensional (n-D) lattice(s). The bound is obtained based on constructing an n-D lattice which consists of parallel layers. Each layer is selected as a translated version of a densest (n-1)-D lattice. The relative positioning of the layers is adjusted to make the coding gain as large as possible. For large values of n, the bound is improved through tightening Ryskov's inequality on covering radius and minimum distance of a lattice.

关键词： coding gain Covering radius Densest lattices Lattice sphere packing Minimum distance

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Low ML-Decoding Complexity, Large coding gain, Full-Rate, Full-Diversity STBCs for 2 x 2 and 4 x 2 MIMO Systems

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IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING 2009年第6期3卷 916-927页

作者： Srinath, K. Pavan Rajan, B. Sundar Indian Inst Sci Dept Elect Commun Engn Bangalore 560012 Karnataka India

This paper deals with low maximum-likelihood (ML)-decoding complexity, full-rate and full-diversity space-time block codes (STBCs), which also offer large coding gain, for the 2 transmit antenna, 2 receive antenna (2 x 2) and the 4 transmit antenna, 2 receive antenna (4 x 2) MIMO systems. Presently, the best known STBC for the 2 2 system is the Golden code and that for the 4 x 2 system is the DjABBA code. Following the approach by Biglieri, Hong, and Viterbo, a new STBC is presented in this paper for the 2 x 2 system. This code matches the Golden code in performance and ML-decoding complexity for square QAM constellations while it has lower ML-decoding complexity with the same performance for non-rectangular QAM constellations. This code is also shown to be information-lossless and diversity-multiplexing gain (DMG) tradeoff optimal. This design procedure is then extended to the 4 x 2 system and a code, which outperforms the DjABBA code for QAM constellations with lower ML-decoding complexity, is presented. So far, the Golden code has been reported to have an ML-decoding complexity of the order of for square QAM of size. In this paper, a scheme that reduces its ML-decoding complexity to M-2 root M is presented.

关键词： coding gain full-rate space-time block codes (STBCs) low maximum-likelihood (ML)-decoding complexity sphere decoding

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Full-Diversity Full- Rate Space-Frequency Codes with Optimum coding gain for Distributed-Transmission OFDM Systems

Full-Diversity Full- Rate Space-Frequency Codes with Optimum...

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6th Joint IFIP Wireless and Mobile Networking Conference (WMNC)

作者： Shen, Ying Univ Elect Sci & Technol China Natl Key Lab Sci & Technol Commun Chengdu 610054 Peoples R China

ISBN: (纸本)9781467356169;9781467356152

Distributed transmission is a way of simultaneously transmitting the same signal from multiple distributed antennas. This paper focuses on the design of full-rate space-frequency (SF) codes for improving the performance of distributed-transmission OFDM systems over asynchronous multipath channels. Analyzing the conditional pairwise error probability, we show the achievable diversity order Z for distributed-transmission OFDM systems is upper bounded by the total number of delay paths between MT transmit antennas and MR receive antennas. SF codes based on lattice theory are constructed to achieve the diversity order Z. Then, we propose two full-diversity (maximum diversity) SF code design methods. The first method is a cyclic shift coding approach employing different shift lengths for different transmit antennas, and the second method is a cyclic shift superposition coding approach using same shift lengths for different transmit antennas. In order to reduce the decoding complexity while preserving the diversity order, subcarrier grouping based on interleaved partition is performed to the SF codes designed above, which divides all subcarriers into disjoint subsets to carrier different SF code blocks. Moreover, we show that different interleaving methods result in different coding gain due to the effect of the asynchronous delays. Therefore, the detailed design criteria of subcarrier grouping are provided to achieve optimum coding gain. Simulation results show that the proposed full-diversity SF codes induce about 6 dB performance improvement, and optimum subcarrier grouping can achieve 59 dB gain.

关键词： Distributed transmission SF codes full-diversity coding gain

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Modeling of the coding gain of joint coding for multi-program video transmission

Modeling of the coding gain of joint coding for multi-progra...

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1st IEEE International Conference on Multimedia and Expo (ICME2000)

作者： Vincent, A Corriveau, P Blanchfield, P Renaud, R Commun Res Ctr Ottawa ON K2H 8S2 Canada

In digital multi-program video transmission, several video programs are compressed (e.g., using MPEG-2), multiplexed, and transmitted over a constant bit rate (CBR) channel. Joint coding, or statistical multiplexing, which is now widely used in digital television broadcasting, dynamically allocates the available channel capacity among programs according to picture content. This scheme is much more efficient than independent coding where each channel is allocated a fixed bit rate. In this paper, we present a model which can relate the decoded picture quality to bit rate, for both independent and joint coding. The model takes into account statistical variations of video program complexity, and incorporates experimental data drawn from formal subjective picture quality assessments. We use the model to calculate the coding gain of joint coding relative to independent coding, in terms of bandwidth savings.

关键词： joint coding statistical multiplexing picture quality model coding gain picture complexity

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Reed-Solomon(RS) coding gain on Correlated Rayleigh Fading

Reed-Solomon(RS) Coding Gain on Correlated Rayleigh Fading

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IEEE AFRICON Conference - Powering Africa s Sustainable Energy for AD Agenda - The Role ofICT and Engineering.

作者： Omosa, Edwin N. Akuon, Peter O. Kalecha, Oduol V. Univ Nairobi Dept Elect & Informat Engn Nairobi Kenya

ISBN: (纸本)9781728132891

This paper investigates the effects of channel coding in correlated fading channels using Reed-Solomon (RS) codes. The bit error probability performance of RS is carried out by considering binary phase shift keying (BFSK) modulation in correlated Rayleigh Fading channels. It is observed that RS codes reduces errors compared to a situation where they are not used. The bit error rate of coded selection combining(SC) and equal gain combining(EGC) achieved a coding gain over un-coded system.

关键词： Channel coding correlated fading channel coding gain Reed-Solomon codes selection combining and egual gain combining

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Increasing of coding gain of Soft Input Soft Output Channel Decoding

Increasing of Coding Gain of Soft Input Soft Output Channel ...

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16th IEEE Mediterranean Electrotechnical Conference (MELECON)

作者： Zivic, Natasa Univ Siegen Inst Data Commun Syst Siegen Germany

ISBN: (纸本)9781467307840

The subject of this paper is combining of Soft Input Soft Output (SISO) channel decoding and cryptographic mechanisms with some of well known procedures used in communication systems, such as interleaving, puncturing and bit stuffing. The algorithm is proposed, which enables improvement of used channel decoding by interleaving of bits known to the transmitter and the receiver, resulting in additional overall coding gain.

关键词： Channel Decoder coding gain transmitter receivers COMMUNICATION SYSTEMS

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SPARSE TERNARY CODES FOR SIMILARITY SEARCH HAVE HIGHER coding gain THAN DENSE BINARY CODES

SPARSE TERNARY CODES FOR SIMILARITY SEARCH HAVE HIGHER CODIN...

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IEEE International Symposium on Information Theory (ISIT)

作者： Ferdowsi, Sohrab Voloshynovskiy, Slava Kostadinov, Dimche Holotyak, Taras Univ Geneva Dept Comp Sci Geneva Switzerland

ISBN: (纸本)9781509040964

This paper addresses the problem of Approximate Nearest Neighbor (ANN) search in pattern recognition where feature vectors in a database arc encoded as compact codes in order to speed-up the similarity search in large-scale databases. Considering the ANN problem from an information-theoretic perspective, we interpret it as an encoding, which maps the original feature vectors to a less entropic sparse representation while requiring them to he as informative as possible. We then define the coding gain for ANN search using information-theoretic measures. We next show that the classical approach to this problem, which consists of binarization of the projected vectors is sub-optimal. instead, a properly designed ternary encoding achieves higher coding gains and lower complexity.

关键词： Approximate Nearest Neighbor search content identification binary hashing coding gain sparse representation

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