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IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom)

作者： Rashich, Andrey Kislitsyn, Alexandr Gorbunov, Sergei Peter Great St Petersburg Polytech Univ Radio & Telecommun Syst Dept St Petersburg Russia

ISBN: (纸本)9781538670910

A trellis demodulator for spectrally efficient pulse shaped OFDM-signals is proposed. Its' performance is analyzed for a set of optimal pulses obtained as the solution of the optimization problem with restriction to a certain spectrum reduction rate. We consider the pulse shapes of general form with duration equal to OFDM-symbol duration. The iterative version of trellis demodulator for pulse shaped OFDM with FEC is also proposed. The BER performance of proposed iterative demodulator of spectrally efficient pulse shaped OFDM signals is comparable with the one of classic coded OFDM modulation with the same FEC. The performance of proposed algorithms does not depend on the number of subcarriers. They allow to introduce non-orthogonality into OFDM to achieve very good spectral characteristics with small BER degradation.

关键词： OFDM PS-OFDM GFDM iterative receiver map algorithm 5G OOBE

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On the iterative decoding of concatenated partial unit memory codes structures

On the iterative decoding of concatenated partial unit memor...

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1st International Symposium on Wireless Communication Systems (ISWCS 04)

作者： Fagoonee, L Honary, B Univ Lancaster Fac Sci Appl Dept Commun Syst Lancaster LA1 4YW England

ISBN: (纸本)0780384725

The aim of this paper is to describe in detail the iterative decoding algorithm used during the implementation of concatenated Partial Unit Memory (PUM) code structures, such as turbo and woven turbo constructions based on PUM codes. Previous published research by the authors have shown that such concatenated PUM code structures have better distance properties and performance than equivalent structures based on convolutional codes. The decoding algorithm presented is based on the max-log map algorithm used for classical turbo codes with component convolutional codes. Unlike the trellis of a convolutional code, the trellis of PUM codes is characterised by parallel branches between state pairs and multiple input branch labels. We show how the original max-log map algorithm is adapted to cope with the unusual trellis structure of PUM codes. The proof that our algorithm performs satisfactorily is illustrated by the relative performance, for different iterations, of turbo and woven turbo structures based on PUM codes, which approach the Shannon limit.

关键词： iterative decoding map algorithm turbo codes woven turbo codes PUM codes

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An Optimized Resource Efficient Approximation of max* Operator for Recalculation in Turbo Code Decoder 5

An Optimized Resource Efficient Approximation of <i>max</i>*...

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5th International Conference on Enterprise Systems (ES) - Industrial Digitalization by Enterprise Systems

作者： Zhan, Ming Wu, Jun Wen, Hong Southwest Univ Sch Elect & Informat Engn Chongqing 400715 Peoples R China Shanghai Jiao Tong Univ Sch Cyber Secur Shanghai 200240 Peoples R China Univ Elec Sci & Tech China Natl Key Lab Sci & Tech Comm Chengdu 611731 Sichuan Peoples R China

ISBN: (纸本)9781538609361

A family of powerful and resource efficient Turbo codes is developed for sensor networks. In the hardware realization of Turbo code decoder, recalculation of the forward or backward state metrics is an effective method to reduce the size of state metrics cache. To facilitate recalculation of the state metrics, an optimized max* operator is presented in this paper. Calculation of the proposed max* operator includes two correction terms, and each one is approximated by using simple comparing, shifting and addition operations. Moreover, approximation of the proposed max* operator is specially optimized for reverse calculation. Although there is small error in the reverse calculation, it has been shown that the maximum error is about three percent, and the proposed approximation is validity for reverse calculation.

关键词： Turbo code map algorithm max* operator recalculation approximation

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Improved Coding Gain of Clipped OFDM Signal using Avalanche Effect of AES Block Cipher

Improved Coding Gain of Clipped OFDM Signal using Avalanche ...

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IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM)

作者： El-Ganiny, M. Youssef ElAttar, Hussein M. Dahab, Mohamed A. Aboul Elgarf, Talaat A. Higher Technol Inst Elect & Comp Engn Dept Ramadan City 10 Egypt Arab Acad Sci Technol & Maritime Transport Elect & Commun Engn Dept Alexandria Egypt

ISBN: (纸本)9781538607008

Although Orthogonal Frequency Division Multiplexing (OFDM) seems to be a solution to achieve the demand of high data rates and immunity to the multipath fading channel, it has some drawbacks. High Peak to average power ratio (PAPR) is the most significant problem of these drawbacks. The main objective of this paper is to introduce a modified PAPR reduction technique named as samples clipping and then use a new channel coding approach to enhance the Bit Error Rate (BER) performance with a degree of complexity. This approach is performed by enhancing the cooperation between soft decision decoding and cryptography. This approach is also performed with Binary Phase Shift Key (BPSK) and Quadrature Phase Shift Key (QPSK) modulation techniques. The PAPR and BER performance calculations for the proposed system are investigated and validated by MATLAB simulation results. These results are evaluated under Additive White Gaussian Noise (AWGN) in addition to Rayleigh and Rician Fading channels.

关键词： OFDM PAPR Channel coding map algorithm AES Avalanche Effect SIE algorithm SID algorithm

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How tracer objects can improve competitive learning algorithms in astronomy

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Vistas in Astronomy 1994年第PART 3期38卷 317-330页

作者： Hernandez-Pajares, M. Floris, J. Murtagh, F. Department Matemàtica Aplicada i Telemàtica Univ. Politècnica de Catalunya E08080 Barcelona Apartat 30002 Spain Space Telescope-European Coordinating Facility European Southern Observatory D-85748 Garching Karl-Schwarzschild-Str. 2 Germany

The main objective of this paper is to discuss how the use of tracer objects in competitive learning can improve results in stellar classification. To do this, we work with a Kohonen network applied to a reduced sample of the Hipparcos Input Catalogue, which contains missing values. The use of synthetic stars as tracer objects allows us to determine the discrimination quality and to find the best final values of the cluster centroids, or neuron weights. © 1995.

关键词： classification Data analysis Galaxy (the) map algorithm Neural networks Self-Organizing Feature Solar neighbourhood Stars

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Optimal Input Power Backoff of a Nonlinear Power Amplifier for FFT-Based Trellis Receiver for SEFDM Signals 16th

Optimal Input Power Backoff of a Nonlinear Power Amplifier f...

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16th International Conference on Next Generation Teletraffic and Wired/Wireless Advanced Networks and Systems (NEW2AN) / 9th Conference on Internet of Things and Smart Spaces Are You Smart (ruSMART)

作者： Rashich, Andrey Fadeev, Dmitrii Peter Great St Petersburg Polytech Univ St Petersburg Russia

ISBN: (纸本)9783319463018;9783319463001

In this paper BER performance of FFT-based trellis receiver for multicarrier signals with spectrally efficient frequency division multiplexing (SEFDM) is evaluated taking into account the impact of nonlinear distortions caused by nonlinear power amplifier (PA). Values of input power back-off (IBO) corresponding to the best BER performance are obtained. The energy efficiency is quantified with energy loss with respect to the system with ideal linear PA. The energy efficiency of considered system is compared with the one of SEFDM system with detection algorithm based on decision diagram and no coding.

关键词： OFDM SEFDM BER performance Input back-off IBO Iterative receiver map algorithm 5G

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PERFORMANCE COMPARISON OF TURBO CODES WITH LDPC CODES AND WITH BCH CODES FOR FORWARD ERROR CORRECTING CODES

PERFORMANCE COMPARISON OF TURBO CODES WITH LDPC CODES AND WI...

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IEEE Student Conference on Research and Development (SCOReD)

作者： Alwan, Mohammed Hasan Singh, Mandeep Mahdi, Hussain Falih Univ Kebangsaan Malaysia Fac Engn & Built Environm Dept Elect Elect & Syst Bangi Malaysia Univ Diyala Comp & Software Engn Dept Baqubah Iraq

ISBN: (纸本)9781467395724

In the field of communication, one of the most thriving and prevalent subject is the channel coding. Channel coding generally deals with the bandwidth which is the bit-rate or information storage capacity. It is a technical field which relies heavily on cost. In fact, it is undeniable that cost is the most crucial element in every system. Nowadays, together with the latency or time element which is also an equally significant factor, especially in mobile communication. The objective of this paper is to analyse and compare distinctively the three types of codes namely, turbo codes, LDBC codes and BCH codes, all simulated respectively in MATLAB environment. According to the conducted studies, it is evident that the BCH codes are excellent in performance compared to other codes. The turbo code, despite requiring maximum processing to decode the message has fairly good performance as well. Regardless of the level of processing, all the codes possess good & reliable performances compared to other codes.

关键词： Channel coding Turbo code LDPC code map algorithm belief propagation BCH codes

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Realization of Turbo Decoder on Coarse Grained Reconfigurable Architectures 19

Realization of Turbo Decoder on Coarse Grained Reconfigurabl...

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19th IEEE-India-Council International Conference (INDICON)

作者： Sekhar, Swathi Gopinathan, Yadukrishnan Yamuna, B. Balasubramanian, Karthi Amrita Vishwa Vidyapeetham Amrita Sch Engn Dept Elect & Commun Engn Coimbatore Tamil Nadu India

ISBN: (纸本)9781665473507

Error correcting codes such as turbo codes are incorporated in present-day wireless and satellite communication systems for error free data transmission. Conventional turbo decoders use the map algorithm to achieve near Shannon limit performance. Many hardware implementations of turbo decoders are carried out on FPGAs. But there is inefficiency in the realization of such complex designs with respect to area and power compared to that of ASICs. This work highlights the realization of a turbo decoder on coarse grained reconfigurable architectures (CGRAs)- a new class of programmable hardware that amalgamates the advantages of both ASICs and FPGAs. For the modelling, exploration and implementation of such architectures, hardware designers have developed many platforms. In this work,the realization of complex iterative loops of turbo decoder on CGRAs, are carried out using CGRA-ME framework, thus eliminating the complexity involved in its FPGA equivalent. The turbo decoder benchmark is implemented on ADRES and flavours of Simple CGRAs. The corresponding configuration bitstreams and the Verilog HDLs generated, are used to perform the area and power analysis. The decoder implemented on ADRES results in the reduction of area by 15.48% and 35.21% compared to that of Simple diagonal and Simple orthogonal respectively. The net power consumed by Simple orthogonal is less in comparison to Simple diagonal by 41.68% and with that of ADRES by 6.36%.

关键词： Turbo decoder map algorithm CGRA ADRES Simple

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Code recognition for dual N-ary orthogonal hybrid modulation systems

Code recognition for dual <i>N</i>-ary orthogonal hybrid mod...

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International Symposium on Intelligent Signal Processing and Communication Systems

作者： Qiao, Xiaoqiang Zhao, Hangsheng Cai, Yueming Nanjing Telecommun Technol Inst Nanjing Peoples R China Nanjing Inst Commun Engn Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781424414468

Dual N-ary orthogonal hybrid modulation system can increase the data rate greatly compared with conventional N-ary orthogonal spread spectrum system, so it can be used for high rate data communication. In this paper, three code recognition algorithms are presented for dual N-ary orthogonal hybrid modulation system. Then the performance of the system in AWGN and flat Rayleigh fading channel with the three different code recognition algorithms is simulated. The simulation results show that the simplified map algorithm is best for the system with a compromise between the performance and the complexity.

关键词： code recognition N-axy orthogonal SS hybrid modulation map algorithm

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A Novel State Metric Normalization Technique for High-Throughput Maximum-a-Posteriori-Probability Decoder

A Novel State Metric Normalization Technique for High-Throug...

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2nd International Conference on Advances in Computing, Communications and Informatics (ICACCI)

作者： Shrestha, Rahul Paily, Roy Indian Inst Technol Guwahati Dept Elect & Elect Engn Gauhati 781039 Assam India

ISBN: (纸本)9781479924325;9781479926596

In this paper, a new state metric normalization technique is proposed for maximmn-a-posteriori-probability (map) algorithm to enhance the throughput of map decoder. Bite error-rate (BER) performance comparison showed that the map algorithm based on the proposed normalization technique has a coding gain of 0.25 dB at a BER of 10(-4) in comparison with map algorithm based on the subtractive normalization technique. An architecture for map decoder based on the new normalization technique has been proposed with a reduced critical path delay as compared to the contributions in literature. Subsequently, a field-programmable-gate-array (FPGA) implementation of the new map decoder is carried out. Thereby, the proposed decoder based on non-parallel radix-2 and radix-4 architectures are able to achieve high throughputs of 514 Mbps and 1.028 Gbps respectively.

关键词： map algorithm turbo code FPGA ASIC throughput maximum clock frequency and BER performance

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