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90th IEEE Vehicular Technology Conference (IEEE VTC-Fall)

作者： Liu, Zhaofeng Zhang, Lin Wu, Zhiqiang Bian, Jing Sun Yat Sen Univ Sch Elect & Informat Technol Guangzhou 510006 Peoples R China Tibet Univ Dept Elect Engn Lasa 850012 Peoples R China Wright State Univ Dept Elect Engn Dayton OH 45435 USA Sun Yat Sen Univ Sch Data & Comp Sci Guangzhou 510006 Peoples R China

ISBN: (纸本)9781728112206

In this paper, we proposed a novel carrier interferometry (CI) code index modulation aided orthogonal frequency division multiplex (OFDM) differential chaotic shift keying (DCSK) communication system. In our design, we utilize the orthogonality property of CI codes matrix, and propose to transmit more information bits using the index of the CI codes matrix. The input information stream is divided into two subsets. One subset is modulated by the chaotic sequence and then spread by the information-bearing CI codes matrix which carries another information subset. At the receiver, the non-coherent chaotic demodulation and the maximum likelihood detection are respectively performed on these two subsets to retrieve the information. Since more bits can be transmitted while not requiring extra chaotic sequences and remaining the same overall energy, the energy efficiency is improved. Additionally, thanks to the spreading in the frequency domain achieved by the usage of CI codes, the peak to average power ratio (PAPR) can be suppressed. Moreover, theoretical performances including the energy efficiency, the bit error rate (BER) expressions are analyzed. Simulation results are provided to validate the theoretical analysis, and demonstrate the satisfactory PAPR and BER performances achieved by our design.

关键词： carrier interferometry code differential chaos shift keying energy efficiency index modulation orthogonal frequency-division multiplexing

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Low PAPR OFDM-Based DCSK Design With carrier interferometry Spreading codes

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IEEE COMMUNICATIONS LETTERS 2018年第8期22卷 1588-1591页

作者： Liu, Zhaofeng Zhang, Lin Chen, Zuwei Sun Yat Sen Univ Sch Elect & Informat Engn Guangzhou 510006 Guangdong Peoples R China

The multi-carrier aided non-coherent differential chaos shift keying (DCSK) modulated systems suffer from high peak-to-average power ratio (PAPR) due to the summations of multiple modulated signals. In this letter, we present a carrier interferometry (CI) code-aided spreading orthogonal frequency-division multiplexing-based DCSK scheme to suppress the PAPR. Instead of directly transmitting DCSK modulated signals via multiple subcarriers, in our design, each chaotic chip is spread over all available subcarriers by using CI codes, which effectively reduces the coherence among the signals, and thereby reducing PAPR. Furthermore, the theoretical PAPR and bit error rate (BER) performances are analyzed. Simulations are performed over additive white Gaussian noise, frequency selective fading, and flat fading channels. The results verify the effectiveness of our theoretical derivations, and demonstrate that the PAPR performance outperforms the counterpart schemes by exploiting the spreading CI codes, while retaining the satisfactory BER performance.

关键词： Differential chaos shift keying carrier interferometry code spreading orthogonal frequency-division multiplexing peak-to-average power ratio hit error rate

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Adaptive Power Allocation in CI/MC-CDMA System Using Genetic Algorithms

Adaptive Power Allocation in CI/MC-CDMA System Using Genetic...

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1st International Conference on Advances in Computing and Communications

作者： Maity, Santi P. Hati, Sumanta Bengal Engn & Sci Univ Dept Informat Technol Sibpur Howrah India

ISBN: (纸本)9783642227196

Multicarrier code division multiple access (MC-CDMA) is one of the effective techniques for high data rate transmission with large user capacity. The use of carrier interferometry (Cl) codes further improves this user capacity relative to the conventional spreading codes. However. CDMA is interference limited and needs proper power allocation for channel capacity (data transmission rate) improvement. According to Shannon's theorem, channel capacity i.e data transmission rate increases with the increase in transmit power due to an increased signal-to-noise-ratio (SNR). MC-CDMA system being multiuser communication system, both signal and interference power are increased with the increase in transmit power which in turn demands optimum power allocation for transmission capacity improvement. In this paper, we develop an adaptive transmit power allocation technique for carrier interferometry multicarrier code division multiple access (CUMC-CDMA) system using Genetic Algorithms (GA). GA is used to find the optimum transmitted powers that maximize the channel capacity as well as reduce BER values. Objective function is defined as maximum channel capacity in a power constraint scenario. We have reported the performance of both the non-power adaptive and GA based proposed adaptive systems. Simulation results show that significant improvement in BER performance and transmission capacity are achieved in the present system.

关键词： Multicarrier code division multiple access carrier interferometry code power allocation genetic algorithms

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Diversity Assisted Block PIC for synchronous CI/MC-CDMA uplink system using Genetic Algorithms

Diversity Assisted Block PIC for synchronous CI/MC-CDMA upli...

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IEEE Region 10 Colloquium/3rd International Conference on Industrial and Information Systems

作者： Maity, Santi P. Hati, Sumanta Maity, Seba Bengal Engn & Sci Univ Dept Informat Technol Sibpur 711103 Howrah India Coll Engn & Management Dept Elect & Commun Kolaghat 721171 West Bengal India

ISBN: (纸本)9781424428052

This paper investigates the scope of Genetic Algorithms (GA) for performance improvement in multiuser detection through the realization of an efficient block parallel interference cancellation (PIC) technique in a synchronous carrier interferometry/MC-CDMA (multicarrier-code division multiple access) uplink system. Simulation is carried out on frequency selective Rayleigh fading channel and antenna diversity is applied at base station (BS). Weight factors for diversity implementation are calculated based on the value of SIR (signal to interference ratio) of individual antenna system. GA is used to partition different users into groups of different blocks namely very strong, strong, weak and very weak based on the normalized magnitudes of their decision variables. We have reported the performance of the GA based block PIC system of four block, three block and two block with conventional PIC. A significant improvement in performance and capacity is seen with GA based block PIC relative to conventional PIC at the cost of slight increase in computation complexity. Simulation results show that BER is reduced as the number of users are divided into more number of blocks and the optimal partitioning of the blocks obtained by using GA.

关键词： Block PIC carrier interferometry code Diversity Genetic Algorithm MC-CDMA

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PAPR Reduction in synchronous CI/MC-CDMA uplink system using Genetic Algorithms

PAPR Reduction in synchronous CI/MC-CDMA uplink system using...

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International Conference on Communication and Electronics System Design (ICCESD)

作者： Hati, Sumanta Maity, Santi P. Bengal Engn & Sci Univ Dept Informat Technol Howrah 711103 WB India

ISBN: (纸本)9780819495570

Main disadvantage of a multicarrier communication system is high peak to average power ratio (PAPR) of the transmitted signal. The high PAPR causes the performance degradation due to nonlinear distortion in the high power amplifier (HPA). PAPR value is closely depends on transmitted power and correlation properties of the user's spreading code. High peak and low average value of the transmitted power increases the PAPR. On the other side high auto correlation function (ACF) value and low cross correlation function (CCF) value of the spreading code also increases the PAPR. But to eliminate the multiple access interference (MAI) in receiver end, ACF should be peak and CCF should be posses zero for all time shifts. So, there is a conflicting nature of PAPR and bit error rate (BER). That's why an exhaustive effort has been made in this paper for proper distribution of transmitted power within an acceptable range of peak transmitted power and evaluates the new spreading codes using Genetic Algorithms (GA). In general, to obtain optimum PAPR reduction using GA, total searching time to find out the proper amplitude and phase parameters must be accomplished. Simulation results show that PAPR and BER performance using this proposed technique is better than conventional network.

关键词： PAPR ACF CCF carrier interferometry code Power Allocation Genetic Algorithm MC-CDMA

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On the performance of turbo coded carrier interferometry OFDM transmission system

On the performance of turbo coded carrier interferometry OFD...

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6th International Conference on Advanced Communication Technology

作者： Chung, Y Seo, W Pukyong Natl Univ Dept Informat & Commun Pusan 608737 South Korea

ISBN: (纸本)8955191197

A carrier-interferometry (CI) code ensures orthogonality between transmitted symbols using unique phase offsets and thus can provide frequency diversity gain in multicarrier transmission schemes. In an OFDM combined with Cl, each symbol is transmitted on all subcarriers rather than on a single carrier. This paper evaluates the performance of the Cl based OFDM system (CI-OFDM) and its performance is also compared with the performance of a turbo coded CI-OFDM. A turbo code is applied prior to the CI modulation process. For the present investigation, a versatile simulator based on the SPW simulation platform is developed and the comparison shows a performance gain, particularly at higher SNR values.

关键词： carrier interferometry code turbo codes OFDM performance

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Block PIC Technique for Synchronous CI/MC-CDMA system using Neural Network 12

Block PIC Technique for Synchronous CI/MC-CDMA system using ...

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

作者： Hati, Sumanta Maity, Santi P. Bengal Engn & Sci Univ Dept Informat Technol Sibpur 711103 Howrah India

ISBN: (纸本)9781450311960

Multicarrier code Division Multiple Access (MCCDMA) is one of the most promising techniques for high bit rate and high user capacity transmission in future broadband mobile services. The use of carrier interferometry (CI) codes further improves this user capacity relative to the conventional spreading codes. Neural networks (NN) are trained to optimize the weight factor of different users in minimum mean square error combining receiver (MMSEC) via back propagation type algorithm. Optimum values of weight factors give stable decision variables that lead to improve receiver performance without having the knowledge of channel state information and transmit signal powers. Decision variables are then used for realization of efficient block parallel interference cancellation (BPIC) as multiuser detection (MUD). Simulation results show that BER performance using NN is better than conventional network.

关键词： MC-CDMA carrier interferometry code BPIC Neural Network

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