检索结果-内蒙古大学图书馆

Trellis code design for periodic interleavers

IEEE COMMUNICATIONS LETTERS 1999年第4期3卷 103-105页

作者： Wesel, RD Cioffi, JM Univ Calif Los Angeles Dept Elect Engn Los Angeles CA 90095 USA Stanford Univ Stanford CA 94305 USA

A standard technique for correlated fading combines trellis codes designed for independent fading with interleaving that makes correlated fading appear to be independent for symbols within the Viterbi traceback depth. When the fading correlation is persistent and delay constraints preclude deep interleaving, some correlation remains among symbols within the traceback depth. Incorporating this post-interleaver correlation improves the trellis code design. This letter presents such a trellis code design technique for periodic interleavers. Bit error rate simulations demonstrate that the new design technique can provide a dramatic performance improvement when fading or interference is severe and persistent.

关键词： fading channels interleaved coding trellis codes

来源：评论

学校读者我要写书评

暂无评论

Bit-interleaving in fast FH/SSMA systems with M-FSK modulation

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2007年第9期6卷 3154-3158页

作者： Liu, Yu-Sun Natl Taipei Univ Technol Dept Elect Engn Taipei 10608 Taiwan

The effects of hit-interleaving on the performance of convolutional codes and turbo codes in fast frequencyhop/spread-spectrum multiple-access systems with M-FSK modulation are investigated. It is observed that bit-interleaving induces two counter-acting forces on decoder performance. On the one hand, bit-interleaving disperses consecutive error bits caused by a noisy M-ary signal and makes the errors more correctable. On the other hand, the same measure makes it difficult for the decoder to make use of the bit dependency information. Both theoretical upper bounds and simulation results show that bit-interleaving degrades the performance of soft-decision decoded convolutional codes and turbo codes.

关键词： frequency hop communication multi access communication interleaved coding convolutional codes turbo codes

来源：评论

学校读者我要写书评

暂无评论

Spectral efficiency and cutoff rate of random spreading BICM-based CDMA signals with MMSE multiuser receivers

引用

IEEE COMMUNICATIONS LETTERS 2004年第3期8卷 129-131页

作者： Yih, CH Geraniotis, E Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA Univ Maryland Syst Res Inst College Pk MD 20742 USA

We analyze the spectral efficiency and cutoff rate of random spreading bit-interleaved coded-modulation based synchronous code-division multiple-access signals with minimum mean-square error multiuser receivers. Both additive white Gaussian noise and frequency nonselective Rayleigh fading channels are considered. The spectral efficiency and cutoff rate are characterized as functions of the system load, modulation schemes, and signal-to-noise ratio.

关键词： code division multiple access (CDMA) interleaved coding random codes signal detection

来源：评论

学校读者我要写书评

暂无评论

An information theoretic foundation of synchronized detection

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 2001年第12期49卷 2115-2123页

作者： Baltersee, J Fock, G Meyr, H Rhein Westfal TH Aachen Inst Integrated Syst Signal Proc D-52056 Aachen Germany

The constrained capacity of a coherent coded modulation (CM) digital communication system with data-aided channel estimation and a discrete, equiprobable symbol alphabet is derived under the assumption that the system operates on a flat fading channel and uses an interleaver to combat the bursty nature of the channel. It is shown that linear minimum mean square error channel estimation directly follows from the derivation and links average mutual information to the channel dynamics. Based on the assumption that known training symbols are transmitted, the achievable rate of the system is optimized with respect to the amount of training information needed. Furthermore, the results are compared to the additive white Gaussian noise channel, and the case when ideal channel state information is available at the receiver.

关键词： channel capacity fading channels interleaved coding mutual information synchronized detection

来源：评论

学校读者我要写书评

暂无评论

Performance of Underground Cables That Use OFDM Systems for Broadband Power-Line Communications

引用

IEEE TRANSACTIONS ON POWER DELIVERY 2009年第4期24卷 1889-1897页

作者： Anatory, Justinian Theethayi, Nelson Thottappillil, Rajeev Univ Dodoma Coll Informat & Virtual Educ Sch Virtual Educ Dodoma Tanzania Uppsala Univ Div Elect SE-75121 Uppsala Sweden Royal Inst Technol Div Electromagnet Engn SE-10044 Stockholm Sweden

Power-line networks are proposed for broadband data transmission. The presence of multipaths within the broadband power-line communication (BPLC) system, due to stochastic changes in the network load impedances, branches, etc. pose a real challenge as it affects network performance. This paper attempts to investigate the performance of an orthogonal frequency-division multiplexing (OFDM)-based BPLC system that uses underground cables. It is found that when a branch is added in the link between the sending and receiving end, there is an average of 4-dB power loss. In addition, when the terminal impedances of the branches that are connected to the link between the transmitting and receiving end vary from line characteristic impedance to low-impedance values, the power loss (signal-to-noise ratio) is about 0.35 dB/Omega. On the contrary, for an increase in the terminal impedances by 100 Omega above line characteristic impedance, the power loss is 0.23 dB/Omega. When the branch terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. It is shown that to overcome degraded network performance, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used, which could be used for an efficient design of the BPLC system that uses OFDM techniques.

关键词： Branched network broadband communication concatenated coding convolution codes impulse noise interleaved coding multipath channels orthogonal frequency-division multiplexing (OFDM) power-line communication Reed-Solomon codes

来源：评论

学校读者我要写书评

暂无评论

Probabilistic Analysis of Data Interleaving for Reed-Solomon coding in BCMCS

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2008年第10期7卷 3878-3888页

作者： Kang, Kyungtae Univ Illinois Coordinated Sci Lab Urbana IL 61801 USA

In CDMA2000 1xEV-DO Broadcast and Multicast Services (BCMCS), Reed-Solomon coding is applied to the layers above the turbo code, and is particularly effective in correcting long bursts of errors. An additional block interleaving mechanism improves the performance of RS coding by increasing the time diversity, to an extent controlled by the width of the error control block (ECB), which converts error bursts into random patterns. We propose and evaluate a performance model of RS coding under varying conditions of Rayleigh fading on the broadcast channel, within the levels of block interleaving that the BCMCS specification allows. Simulation results show that our model predicts the performance of RS coding accurately. This evaluation will allow a service provider to determine the most efficient RS code for their target service quality, that maximizes the effective data-rate and minimizes the energy required for the RS decoding process.

关键词： Broadcasting Rayleigh channels interleaved coding Reed-Solomon codes

来源：评论

学校读者我要写书评

暂无评论

On channel estimation and sequence detection of interleaved coded signals over frequency nonselective Rayleigh fading channels

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1998年第2期47卷 558-565页

作者： Kong, HW Shwedyk, E Univ Manitoba Dept Elect & Comp Engn Winnipeg MB R3T 5V6 Canada

Due to the receiver complexity introduced by interleaving, the implementation of maximum likelihood (ML) decoding of interleaved coded signals transmitted over frequency nonselective Rayleigh fading channels has been shown to be practically impossible. As an alternative, a two-stage receiver structure has been proposed, where the channel estimation and sequence decoding are done separately. The channel estimation issue in a two-stage receiver is examined in detail in this paper. It is shown that although an optimum [maximum a posteriori (MAP)I channel estimation is not possible in practice, it can be approached asymptotically by joint MAP estimation of the channel and the coded data sequence. The implementation of the joint MAP estimation is shown to be an ML sequence estimator followed by an minimum mean square error (MMSE) channel estimator. Approximate ML sequence estimation using pilot symbol interpolation is also studied, and through computer simulations, its performance is compared to receivers using ML sequence estimation. The effect of decision delay (DD), prediction order, and pilot insertion rate (PIR) on the reduced complexity ML sequence estimation is investigated as well. Finally, a practical receiver is proposed that makes the best compromise among the error performance, receiver complexity, DD, and power (or bandwidth) expansion due to pilot insertion.

关键词： frequency nonselective interleaved coding Rayleigh fading two-stage receiver

来源：评论

学校读者我要写书评

暂无评论

Cell Interleaving Against Impulsive Noise in OFDM

引用

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2012年第2期58卷 269-273页

作者： Torio, Pablo Garcia Sanchez, Manuel Univ Vigo Dept Teoria Senal & Comunicac Vigo 36310 Spain

Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique which is very sensitive to impulsive noise (IN). In this paper, we research the behavior of the OFDM based broadcasting system Digital Radio Mondiale (DRM) against this kind of noise in function of its different transmission modes and interleaving options. This research involves an experiment in which a real DRM signal is modulated, transmitted, received, and demodulated. The results quantitatively show the improvement when deep cell interleaving is used, and also the little influence that transmission mode has on the behavior of DRM against IN. In this paper, it is also explained in a mathematical way why it is advisable to perform deep cell interleaving between several OFDM symbols and not within only one, in order to minimize the effect of IN

关键词： DRM impulse noise interleaved coding OFDM radio broadcasting

来源：评论

学校读者我要写书评

暂无评论

Interleaving distances spectrum comparison between turbo-codes interleavers

Interleaving distances spectrum comparison between turbo-cod...

引用

European Conference on Wireless Technologies

作者： Balta, Horia El Assad, Safwan Politehnica Univ Timisoara Bd Vasile Parvan2 Timisoara 300223 Romania Univ Nantes Ecole Polytech F-44306 La Chantrerie France

ISBN: (纸本)9782960055153

In this paper the interleaving distances spectrum (IDS) is defined. The EDSs for random, block and pseudo-random interleavers are established. The theoretical EDSs for the random and square block interleavers are calculated. On the basis of the EDS, some parameters like the minimum interleaving distance and the spreading degree are defined and calculated. These parameters allow us to make a comparison between different and also same type interleavers.

关键词： concatenated coding interleaved coding permutations spectral analysis turbo-codes

来源：评论

学校读者我要写书评

暂无评论

An integrated scheme for robust distributed speech recognition over lossy packet networks

An integrated scheme for robust distributed speech recogniti...

引用

32nd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Gomez, Angel M. Peinado, Antonio M. Sanchez, Victoria Rubio, Antonio J. Univ Granada Dept Signal Theory Networking & Commun E-18071 Granada Spain

ISBN: (纸本)1424407281

In this work we present a complete set of techniques devoted to offer robustness against frame losses in distributed speech recognition over packet-switched networks. The proposed scheme is composed of tree techniques, two of them are applied at the sender and the last one in the recognizer itself. On one hand, a media-specific Forward Error Correction (FEC) technique is used to allow the recovery of information within the bursts. On the other hand, a recognizer-based technique well known by its remarkable ability to reduce the effects of long consecutive frame losses during recognition, the weighted Viterbi algorithm (WVA), is used to handle the additional information introduced by FEC codes. Moreover, a double stream strategy whereby interleaving can be applied along with FEC codes without any delay increase, is also applied. The application of interleaving allows to reduce the perceived burst length at the receiver, further improving the recognition performance. As a result, the proposed scheme can provide an acceptable performance even under extremely adverse channel conditions.

关键词： speech recognition packet switching channel coding forward error correction interleaved coding

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：