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22nd Iranian Conference on Electrical Engineering (ICEE)

作者： Fotohabady, V. Said, F. Kings Coll London Dept Informat CTR London WC2R 2LS England

ISBN: (纸本)9781479944095

Multipath spread is one of the most important factors which limit data transfer with high bit rate. Data transfer with high bit rate is possible in the range of gigahertz. The main problem in this frequency range is multipath spread. Orthogonal frequency division multiplexing (OFDM) technique divides the transferring symbols between several subcarriers and transfers them simultaneously. Accordingly this technique is very resistant against the adverse effects of multipath spread. As a result of the increasingly grow of systems with high capacity, the uses of this technique increases cumulatively. OFDM system along with MIMO has been offered for the next generations of cell phones. Channel coding plays an important role in improving the efficiency of OFDM. Due to the special structure of OFDM, using channel coding in it, compared with uni-subcarrier systems, has special features which enhance the efficiency of the system. For this reason, this system is also called coded OFDM or COFDM. In this article in addition to studying the OFDM technique, we will consider the role of the delay spread of the channel in increasing the coding interest of the channel and the efficiency of OFDM system.

关键词： OFDM modulation channel coding data communication error statistics mobile handsets modulation coding multipath channels next generation networks spread spectrum communication COFDM MIMO channel coding channel delay spread effect coded OFDM system efficiency data transfer high bit rate multipath spread next generation cell phone orthogonal frequency division multiplexing technique symbol transfer unisubcarrier system Bit rate Delays Encoding modulation Noise OFDM Wireless communication

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INTERSYSTEM JAMMING OF WIRELESS COMMUNICATIONS BASED ON UWB NOISE SIGNALS 24

INTERSYSTEM JAMMING OF WIRELESS COMMUNICATIONS BASED ON UWB ...

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24th International Crimean Conference Microwave & Telecommunication Technology (CriMiCo)

作者： Kalinin, V., I Radchenko, D. E. Cherepenin, V. A. RAS Kotelnikov Inst Radio Engn & Elect Fryazino Branch Inst Russian Acad Sci 1 Vvedenskogo Sq Fryazino 141190 Moscow Reg Russia

ISBN: (纸本)9789663354125

Numerical simulation of UWB noise communications with spectrum spreading is performed. It is detected that the intersystem jamming appearing in result of code spectrum modulation. Noise performance of UWB communication system is investigated for a single-ray channel with additive Gaussian white noise. The new method of intersystem jamming reduction is proposed when nonmultiple time delays of noise informative signals are used.

关键词： AWGN channels interference suppression jamming modulation coding numerical analysis spread spectrum communication synchronisation ultra wideband communication UWB communication system UWB noise communications UWB noise signals additive Gaussian white noise code spectrum modulation intersystem jamming reduction noise informative signals noise performance numerical simulation single-ray channel spectrum spreading time delays wireless communications Noise Organizing

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Increasing the Throughput of HARQ via Multi-packet Transmission

Increasing the Throughput of HARQ via Multi-packet Transmiss...

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IEEE Global Communications Conference (GLOBECOM)

作者： El Hamss, Aata Szczecinski, Leszek Piantanida, Pablo INRS EMT Montreal PQ Canada SUPELEC Gif Sur Yvette France

ISBN: (纸本)9781479935123

In this work we consider incremental redundancy hybrid ARQ (HARQ) transmission of data packets over independent block-fading channels. In HARQ, the transmitter, upon request (NACK), resends the "NACKed" packet in the next available block. Conventionally, the original and retransmitted packets occupy one block, each. In our approach, we allow the transmitter to share the resources between the new and the retransmitted packets. To implement such a multi-packet transmission we consider the superposition coding and the time-sharing modulation as possible encoding schemes for simultaneous transmission of both packets. Targeting the maximization of the throughput, we cast the problem into the framework of Markov decision process (MDP), where the decisions about the optimal transmission strategy are taken using information about the state of the receiver in the previous transmissions. Numerical examples obtained in a Rayleigh block-fading channel show that proposed transmission

关键词： Markov processes Rayleigh channels automatic repeat request data communication decision theory modulation coding radio receivers radio transmitters HARQ transmission MDP Markov decision process NACKed packet Rayleigh block-fading channel data packets encoding schemes hybrid ARQ transmission multipacket transmission superposition coding time sharing modulation transmission strategy Decoding Encoding Optimization Radiation detectors Receivers Throughput Transmitters

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Packet Appending for BICM-ID - Simplified Receiver Design 9

Packet Appending for BICM-ID - Simplified Receiver Design

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9th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP)

作者： Krasicki, Maciej Poznan Univ Tech Chair Wireless Commun Poznan Poland

ISBN: (纸本)9781479925810

The author revises his concept of Packet Appending for Bit-Interleaved Coded modulation with Iterative Decoding (PA-BICM-ID) and proposes a new receiver design in which some demapper operations are called in every iterative decoding pass, as previously, but the rest is called only in the first iteration, thereby reducing the computational cost. Afterwords, it is shown that PA-BICM-ID can considerably improve the performance of such systems that originally employ low-order modulation. The decoding convergence is examined by means of the EXtrinsic Information Transfer (EXIT) chart, whereas the overall system performance over uncorrelated Rayleigh fading channel is analyzed using computer simulation.

关键词： modulation coding throughput signal processing iterative decoding system analysis and design

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Interference Suppression Using EM Algorithm in OFDM Transmissions

Interference Suppression Using EM Algorithm in OFDM Transmis...

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IEEE Global Communications Conference (GLOBECOM)

作者： Yoda, Naotoshi Ohtsuki, Tomoaki Mashino, Jun Sugiyama, Takatoshi Keio Univ Dept Informat & Comp Sci Kohoku Ku 3-14-1 Hiyoshi Yokohama Kanagawa 2238522 Japan NTT Access Network Serv Syst Labs Yokosuka Kanagawa 2390847 Japan

ISBN: (纸本)9781479935123

Interference detection and suppression schemes are proposed for coded OFDM systems in the presence of narrow-band interference. Previously proposed interference detection schemes perform with a recursive forward error correcting (FEC) decoding, thus its calculation is heavy. The proposed scheme is based on an expectation maximization (EM) algorithm to detect the interference before the FEC decoding process. The complexity is reduced because the FEC decoding is performed only once. Simulation results indicate that the proposed scheme achieves almost the same bit error rate performance as the conventional scheme, while decreasing the times of the FEC decoding.

关键词： OFDM modulation error statistics expectation-maximisation algorithm forward error correction interference suppression iterative decoding modulation coding radiocommunication recursive estimation signal detection EM algorithm bit error rate performance coded OFDM transmission system expectation maximization algorithm interference suppression scheme narrowband interference detection scheme recursive FEC iterative decoding wireless communication Bit error rate Decoding Forward error correction Interference Iterative decoding OFDM Receivers

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A coding Scheme Using Redundant Bits for Bit Patterned Media Recording Channel without Overshoot

A Coding Scheme Using Redundant Bits for Bit Patterned Media...

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Annual Summit and Conference of Asia-Pacific-Signal-and-Information-Processing-Association (APSIPA)

作者： Arrayangkool, Autthasith King Mongkuts Inst Technol Ladkrabang Coll Data Storage Innovat Bangkok 10520 Thailand

ISBN: (纸本)9786163618238

In bit patterned magnetic recording (BPMR), The two-dimensional (2D) interference composed of inter-symbol and inter-track interference is a major problem especially at high areal density (AD). One way to alleviate the destructive effect of 2D interference is to deploy a 2D coding scheme on an input data sequence before recording in order to avoid some data patterns that easily cause an error at the data readback process. However, some coding schemes generate high complexity. Consequently, this paper proposes a new low-complexity modulation code with redundant bits to eliminate the data patterns leading to severe 2D interference and compare overall system performance. Experimental results indicate that the system with the proposed code is superior to that without coding, especially when the AD is high and/or the position jitter is large.

关键词： intersymbol interference jitter magnetic recording modulation coding 2D coding scheme 2D interference BPMR areal density bit patterned media recording channel data patterns data readback process data sequence intertrack interference modulation code position jitter Abstracts Bit error rate Encoding Interference Jitter Magnetic recording Signal to noise ratio

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Optimal Resource Allocation for Type-II HARQ based OFDMA Ad Hoc Networks under Individual Rate and PER Constraints 79

Optimal Resource Allocation for Type-II HARQ based OFDMA Ad ...

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IEEE 79th Vehicular Technology Conference (VTC-Spring)

作者： Ksairi, Nassar Ciblat, Philippe Le Martret, Christophe J. Telecom ParisTech F-75013 Paris France Thales Commun & Secur F-92622 Gennevilliers France

ISBN: (纸本)9781479944828

We address the problem of multiuser power and bandwidth allocation for Orthogonal Frequency Division Multiple Access (OFDMA) networks employing a Type-II Hybrid Automatic Repeat reQuest (HARQ) mechanism, practical coding and modulation Schemes (MCSs) and Bit Interleaved Coded modulation (BICM). The problem is formulated as minimizing the sum power required to satisfy a goodput constraint for each link while its post-HARQ Packet Error Rate (PER) does not exceed a certain threshold. Assuming statistical Channel State Information (CSI), we propose a computationally-efficient algorithm to compute the corresponding optimal resource allocation. We finally provide a practical selection of the MCSs that significantly boosts the performance of the proposed resource allocation algorithm.

关键词： OFDM modulation ad hoc networks automatic repeat request bandwidth allocation frequency division multiple access modulation coding resource allocation BICM MCS OFDMA ad hoc networks bit-interleaved coded modulation coding-modulation scheme goodput constraint multiuser power allocation optimal resource allocation orthogonal frequency division multiple access networks post-HARQ packet error rate statistical CSI statistical channel state information sum power minimization type-II HARQ mechanism type-II hybrid automatic repeat request mechanism Ad hoc networks Bandwidth Encoding Minimization OFDM Resource management Wireless communication Resource utilization Orthogonal frequency division multiplexing bandwidth allocation Ad hoc networks management of resources Frequency division multiaccess OFDMA modulation coding Automatic repeat request Bit interleaved coded modulation CARRIER SYSTEM HARQ Channel state information MCS gene Bandwidth

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Backscatter Communication and RFID: coding, Energy, and MIMO Analysis

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第3期62卷 770-785页

作者： Boyer, Colby Roy, Sumit Univ Washington Dept Elect Engn Seattle WA 98195 USA

Radio Frequency IDentification (RFID) is intended to supplant legacy (optical) bar code scanning technology found in many logistic and retail applications. RFID is distinguished by inexpensive, low power and compact form factor tags, whose longevity and efficacy are predicated on using passive communication techniques and on-tag power harvesting. Such tags employ backscatter modulation, which does not require any active RF components. As a result, backscatter has become an attractive design choice for short-range communications in power constrained wireless sensor networking scenarios. The purpose of this work is two-fold. First, it aims to expose backscatter communication as an emerging topic to a communication systems-theoretic audience. Since backscatter modulation and on-tag power harvesting efficiency are coupled, it is necessary to re-examine notions of power and spectral efficiency from an energy-constraint perspective;this leads to novel coded modulation schemes for future RFID systems. Further, we investigate RFID MIMO systems where the channel fading encountered has different statistics than the classical Rayleigh fading model. In turn, the trade off between diversity order and spatial multiplexing gains are distinct from wide-area MIMO.

关键词： Radio communication scattering RFID tags MIMO modulation modulation coding fading wireless sensor networks

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A Type II Hybrid ARQ Protocol with Adaptive modulation and coding for Time-Correlated Fading Channels: Analysis and Design

A Type II Hybrid ARQ Protocol with Adaptive Modulation and C...

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IEEE International Conference on Communications (ICC)

作者： J. S. Harsini F. Lahouti M. Levorato M. Zorzi School of Electrical and Computer Engineering University of Tehran Tehran Iran Department of Electrical Engineering University of Stanford USA Department of Information Engineering University of Padova Padova Italy

This paper presents performance analysis and cross-layer design approaches for hybrid ARQ (HARQ) protocol in wireless networks which employ adaptive modulation and coding (AMC) at the physical layer and are subject to time-correlated fading channels. Utilizing a Markov channel model which accounts for the temporal correlation in successive parity transmissions by the adaptive rate HARQ protocol, we derive the system throughput and the packet loss probability based on a rate compatible punctured convolutional (RCPC) code family. As an application, we then present a cross-layer AMC design which takes into account the performance gain of the HARQ protocol at the link layer. The results illustrate that including AMC in the HARQ protocol leads to a substantial throughput gain, but the channel correlation strongly diminishes the performance of the HARQ protocol in terms of throughput and packet loss rate.

关键词： Automatic repeat request modulation coding Fading Throughput Performance gain Performance analysis Cross layer design Wireless application protocol Wireless networks Adaptive systems

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Multi-Group Wireless Multicast Broadcast Services Using Adaptive modulation and coding: Modeling and Analysis

Multi-Group Wireless Multicast Broadcast Services Using Adap...

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IEEE Conference on Vehicular Technology (VTC)

作者： Yu-Cheng Liang Ching-Chun Chou Hung-Yu Wei Department of Electrical Engineering National Taiwan University Taiwan

Adaptive modulation and coding (AMC) is attracting research interest in wireless multicast broadcast services (MBS). AMC increases the system throughput by utilizing possible good channel states instead of using robust modulation and coding schemes. A model for the AMC in an MBS system with multiple MBS groups is provided, and stochastic analysis using Markov chain is also applied for modeling analysis. Simulation results show extremely high correspondence to the proposed mathematical model.

关键词： modulation coding Feedback Robustness Throughput Mathematical model Radio broadcasting Switches Base stations Data communication Stochastic systems

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