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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： M. Harada T. Yamazato M. Katayama A. Ogawa Department of Electronics & Electrical Engineering University of Nagoya Nagoya Japan Center for Information Media Studies Sciences University of Nagoya Nagoya Japan Department of Information Meijo University Nagoya Japan

In an attempt to improve the performance under a frequency selective fading environment, we propose an orthogonal frequency division multiple access (OFDM) system in which MTCM (multiple trellis coded modulation) is applied to a set of multiple subcarriers. The code is designed to enlarge the summation of the Euclidean distance and the product distance. We also propose a scheme for assigning the symbols to subcarriers adaptively based on the channel state information (CSI) fed back from the reception receive end, and evaluate the performance applying these two codes and the proposed scheme under a multipath Rayleigh fading environment.

关键词： modulation coding OFDM modulation Fading Euclidean distance Interleaved codes Channel state information Rayleigh channels Robustness Multidimensional systems AWGN

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Performance of soft-output space-time equalization for EGPRS

Performance of soft-output space-time equalization for EGPRS

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IEEE Conference on Vehicular Technology (VTC)

作者： C. Luschi A.M. Kuzminskiy P. Strauch B. Mulgrew Bell Laboratories Lucent Technologies Inc. Swindon UK

The use of antenna arrays can help to combat cochannel interference (CCI) in wireless cellular systems. In interference-limited scenarios, spatio-temporal filtering techniques based on a deterministic least-square (LS) approach may be competitive with respect to trellis based algorithms, because of the difficulties of accurately modelling the space-time characteristics of CCI. We consider the impact on the receiver performance of the quality of the reliability information on the coded bits, computed at the output of the deterministic space-time equalizer. Simulation results are provided for an EGPRS receiver employing linear and decision-feedback training-based filtering techniques.

关键词： Nonlinear filters Filtering Radiofrequency interference Iterative decoding GSM Decision feedback equalizers Antenna arrays modulation coding Circuits Space technology

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Concepts for IP-based radio interface in the BRAIN framework

Concepts for IP-based radio interface in the BRAIN framework

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： P. Bertin A. Kadelka J. Rapp A. Lappetelainen B. Wegmann H. Li France Telecom. R&D Cesson-Sevigne France ComNets RWTH Aachen University of Technology Germany Nokia Research Center Finland Siemens AG Germany Ericsson Eurolab Germany Germany

Considering that mobile communications systems and the Internet are key technologies for the development of the information society, one objective of the European IST project BRAIN is the design of a mobile broadband IP radio interface. This radio interface is based on the ETSI HIPERLAN Type 2 standard with some enhancements necessary to optimise the system for the delivery of IP broadband services with high QoS and mobility requirements. The project is working on optimising layer 2 algorithms and protocols for IP mobile services such as adapted schedulers, optimised handover procedures, handling of a standby mode and specifying a dedicated LP Convergence Layer able to transport efficiently IP version 4 as well as version 6 packets over the air and interworking with LP mobility and QoS functions.

关键词： Physical layer Convergence Quality of service Hydrogen Access protocols OFDM modulation modulation coding Internet Telecommunication standards Roaming

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Performance analysis of hierarchical coded modulation systems

Performance analysis of hierarchical coded modulation system...

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Globecom '00 - IEEE. Global Telecommunications Conference. Conference Record (Cat. No.00CH37137)

作者： J.-H. Lim S.B. Gelfand School of Electrical and Computer Engineering Purdue University West Lafayette IN USA

In this paper, analytical performance bounds are presented for a hierarchical coded modulation system of the type which has been proposed for backward compatibility and/or variable error rate protection. This system uses two convolutional encoders (and two Viterbi (1989) decoders) with a hierarchical 16-QAM constellation, and is compatible with an existing QPSK based coded system. In the AWGN channel, we derive upper bounds for four different schemes (two decoding schemes, multi-stage decoding (MSD) and independent decoding(ID), and two labeling schemes, Gray labeling (GL) and non-Gray labeling (NGL)). We show that the performance of the simple GL with ID scheme is nearly optimum in the AWGN channel. Then we analyze the GL with ID scheme in the Rayleigh fading channel. Simulation results are given for comparison with the bounds.

关键词： Performance analysis modulation coding Decoding Labeling AWGN channels Error analysis Protection Convolutional codes Viterbi algorithm Quadrature phase shift keying

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Combined coding and spreading in downlink CDMA systems

Combined coding and spreading in downlink CDMA systems

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IEEE Conference on Vehicular Technology (VTC)

作者： J. Lassing A. Persson T. Ottosson E. Strom A. Svensson Department of Signals and Systems Chalmers University of Technology Goteborg Sweden

Changing from orthogonal spreading codes in a direct-sequence CDMA (DS-CDMA) system to more powerful forward error correcting convolutional codes is proven superior in an asynchronous uplink system. This approach is referred to as code-spread CDMA (CS-CDMA). In this paper these two systems are compared in a synchronous downlink scenario. Both systems are assumed to operate over channels with nonzero delay spread, making it difficult to maintain orthogonality between users at the receiver. Using synchronous transmission, the DS-CDMA system is found to outperform the CS-CDMA system at high loads on all simulated channels. However, it is found that if the CS-CDMA system is allowed to transmit different users asynchronously through independent fading channels, like in an uplink scenario, it outperforms the synchronous downlink DS-CDMA system already on channels with modest delay spread.

关键词： Downlink Multiaccess communication Bandwidth Delay Forward error correction modulation coding Error correction codes Base stations

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Joint detection and estimation in space-time coding and modulation

Joint detection and estimation in space-time coding and modu...

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Asilomar Conference on Signals, Systems & Computers

作者： C. Cozzo B.L. Hughes Center for Advanced Computing and Communication Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA

We consider joint channel estimation and data symbol detection for multipath radio channels with multiple antennas at the transmitter and receiver. An iterative space-time receiver is proposed, based on the expectation-maximization algorithm. We examine the performance of this receiver on the Rayleigh fading channel for transmit diversity and space-time coding methods. Simulation results show that the proposed receiver can often achieve near-coherent performance with modest complexity (2-3 iterations) and using very few training symbols.

关键词： modulation coding Receivers Transmitting antennas Receiving antennas Iterative algorithms Channel estimation Fading Antenna arrays Radio transmitters Wireless communication

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A method for coding of two-level facsimile pictures in systems based on digital modulation of signals

A method for coding of two-level facsimile pictures in syste...

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International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service (TELSIKS)

作者： D. Bandjur M. Mirkovic M. Bandjur M. Andjelkovic Faculty of Mechanical Engineering Pristina Yugoslavia Telekom Srbija A. D Pristina Yugoslavia

In this paper is proposed a new code procedure for coding of two-level facsimile pictures in systems for transmission based on digital modulation of signals. This code procedure provides a very efficient (high compres... 详细信息

关键词： Facsimile Digital modulation Iterative decoding Code standards Testing modulation coding Bit rate Phase shift keying Quadrature amplitude modulation Mechanical engineering

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Service and system enhancements for TDMA digital cellular systems

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IEEE PERSONAL COMMUNICATIONS 1999年第3期6卷 20-33页

作者： Austin, M Buckley, A Coursey, C Hartman, P Kobylinski, R Majmundar, M Raith, K Seymour, JP Lucent Technol Whippany NJ USA Ericsson Res Triangle Pk NC 27709 USA

Throughout 1998, the TDMA community investigated and defined an enhanced suite of voice and data services for TIA/EIA-136 while also improving its basic system capabilities. These enhancements, collectively named 136+, provide improved voice quality, increased capacity, higher data rates, and improved tools for RF system engineering. The enhancements are obtained by introducing a new modulation scheme (8-PSK), new slot formals, and the addition of several new interleaving and coding options. As a result, TIA/EIA-136 now supports a new vocoder mode, the GSM Enhanced Full-Rate (US1) for improved fidelity applications, a robust IS-641 vocoder mode with a 4 dB FER enhancement on the IS136 downlink, and a new packet data service capable of providing usable data rates of 14.4, 28.8, or 43.2 kb/s on a full-rate, double full-rate, or triple full-rate channel, respectively. The packet data service is truly evolutionary in nature, having a new medium access control layer with a network layer very similar to that used for the existing digital control channel. In addition, it maximizes commonalities among TDMA technologies, using identical higher layers and network architecture to the General Packet Radio Service specified in GSM. furthermore, by using a concept known as tunneling to pass TIA/EIA-136 messages through the GPRS network elements, the existing features defined on the DCCH are maintained. This article provides an overview of these 136+-applications, as well as insight into additional near-term improvements, such as the ability to support six voice users per 30 kHz (TDMA6), downlink time diversity, and fast power control.

关键词： Time division multiple access Vocoders GSM Downlink Radio frequency Data engineering Systems engineering and theory modulation coding Interleaved codes Robustness

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Digital terrestrial television (COFDM 8K system) field trials and coverage measurements in Spain

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IEEE TRANSACTIONS ON BROADCASTING 1999年第2期45卷 171-176页

作者： Arrinda, A Vélez, MM Angueira, P de la Vega, D Ordiales, JL Univ Basque Country ETSII & IT Bilbao Bilbao 48013 Spain

This contribution presents the results of the first digital terrestrial television field trials and coverage measurements in spain. First of all the VIDITER project is presented. The main objective of this work is to study the behavior of a whole digital terrestrial television network, from source coding up to the final signal reception, At this point, the experimental network installed in Madrid-will be described. Next, the measurement campaign is explained, first, by describing the network configuration used for these first field trials, and then, paying attention to the criteria used to select the measurement points and the parameter set to be tested. Some of the results obtained will be shown as a first approach to the figures needed to develop and plan a fully operational digital terrestrial television service.

关键词： TV Radio transmitters Digital modulation modulation coding System testing Interference Laboratories Frequency synchronization Antenna measurements Sea measurements

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Reduction of decoding complexity of trellises for BCM

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IEE PROCEEDINGS-COMMUNICATIONS 1999年第2期146卷 82-88页

作者： Petronio, MA Carrasco, RA Staffordshire Univ Sch Engn & Adv Technol Beaconside ST18 0AD Staffs England

Block-coded modulation (BCM) combines bandwidth-efficient modulation techniques with error-correction capabilities to allow efficient data transmission over communication channels. The disadvantage of this technique, however, is the complexity of the trellis used in the Viterbi decoding, process. The authors address this problem and propose a method for the reduction of decoding complexity. Optimal sectionalisation has been identified as an appropriate technique and it is applied to trellises of BCM schemes based on a set of new objective functions. The resulting sectionalisation algorithm has been applied to various BCM schemes including 4-PSK, 8-PSK and 16-PSK and a complexity reduction of approximately 20% is achieved. Extensive simulation las shown that both original and sectionalised trellises have the same performance: over Rayleigh, K = 6 Rician and K = 10 Rician fading channels. Furthermore, a comparison between the considered BCM schemes and ring-TCM is provided in term of code performance and decoding complexity.

关键词： computational complexity modulation coding communication channels error-correction capabilities objective functions block-coded modulation data transmission 16-PSK Rician channels block codes Rayleigh fading channels modulation and coding methods Rayleigh channels bandwidth-efficient modulation techniques Rician fading channels Viterbi decoding optimal sectionalisation BCM phase shift keying trellises 8-PSK Codes ring-TCM 4-PSK decoding complexity reduction

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