• Title/Summary/Keyword: Receiver Complexity

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The Secure Communication using Complexity (복잡계를 이용한 비밀 통신)

  • 배영철
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.2
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    • pp.365-370
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    • 2004
  • In this paper, complexity secure communication was presented. The complexity circuit is used to State-Controlled Cellular Neural Network(SC-CNN). We make a complexity circuit using SC-CNN with the N-double scroll. A complexity circuit is created by applying identical n-double scrolls with coupled method, to each cell. complexity synchronization was achieved using drive response synchronization between the transmitter and receiver about each state in the SC-CNN. From the result of the recovery signal through the demodulation method in the receiver. We shown that recovery quality in the receiver is the similar to other secure communication methods.

Efficient LDPC-Based, Threaded Layered Space-Time-Frequency System with Iterative Receiver

  • Hu, Junfeng;Zhang, Hailin;Yang, Yuan
    • ETRI Journal
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    • v.30 no.6
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    • pp.807-817
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    • 2008
  • We present a low-density parity-check (LDPC)-based, threaded layered space-time-frequency system with emphasis on the iterative receiver design. First, the unbiased minimum mean-squared-error iterative-tree-search (U-MMSE-ITS) detector, which is known to be one of the most efficient multi-input multi-output (MIMO) detectors available, is improved by augmentation of the partial-length paths and by the addition of one-bit complement sequences. Compared with the U-MMSE-ITS detector, the improved detector provides better detection performance with lower complexity. Furthermore, the improved detector is robust to arbitrary MIMO channels and to any antenna configurations. Second, based on the structure of the iterative receiver, we present a low-complexity belief-propagation (BP) decoding algorithm for LDPC-codes. This BP decoder not only has low computing complexity but also converges very fast (5 iterations is sufficient). With the efficient receiver employing the improved detector and the low-complexity BP decoder, the proposed system is a promising solution to high-data-rate transmission over selective-fading channels.

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Performance of Energy Detection Spectrum Sensing with Delay Diversity for Cognitive Radio System

  • Kim, Eun-Cheol;Koo, Sung-Wan;Kim, Jin-Young
    • Journal of electromagnetic engineering and science
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    • v.9 no.4
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    • pp.194-201
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    • 2009
  • In this paper, a new spectrum sensing method based on energy detection is proposed and analyzed in a cognitive radio(CR) system. We employ a delay diversity receiver for sensing the primary user's spectrum with reasonable cost and complexity. Conventional CR with the receiver equipping multiple antennas requires additional hardware and space for installing multiple antennas in accordance with increase in the number of antennas. If the number of antennas increases, detection probability as well as hardware complexity and cost rise. Then, it is difficult to make a primary user detector practically. Therefore, we adopt a delay diversity receiver for solving problems of the conventional spectrum detector utilizing multiple antennas. We derive analytical expressions for the spectrum sensing performance of the proposed system. From the simulation results, it is demonstrated that the primary user detector with the delay diversity receiver has almost half the complexity and shows similar or improved performance as compared with that employing multiple antennas. Therefore, the proposed spectrum sensing structure can be a practical solution for enhancing the detection capacity in CR system operations. The results of this paper can be applied to legacy CR systems with simple modifications.

A Receiver Architecture with Low Complexity for Chirp Spread Spectrum in IEEE 802.15.4a (IEEE 802.15.4a Chirp SpreadSpectrum을 위한 저복잡도 수신기 구조)

  • Kim, Yeong-Sam;Chong, Jong-Wha
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.8
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    • pp.24-31
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    • 2010
  • A receiver architecture with low complexity for chirp spread spectrum (CSS) of IEEE 802.15.4a is proposed. To demodulate the received signal at the highest signal to noise power ratio, matched filter is generally adopted for the receiver of wireless communication systems. It is, however, not resonable to adjust the matched filter to the receiver of CSS whose objectives are low complexity, low cost and low power consumption since complexity of the matched filter is high. In this paper, we propose a new receiver architecture using differential multiplication and accumulator not matched filter for demodulation. Also, bi-orthogonal decoder implemented by only adder/subtractor is proposed. The hardware resources for implementation are reduced in the proposed receiver architecture, although bit error rate performance is low compared with the receiver architecture based on the matched filter.

A Novel Adaptive Turbo Receiver for Large-Scale MIMO Communications

  • Chang, Yu-Kuan;Ueng, Fang-Biau;Tsai, Bo-Yi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.7
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    • pp.2998-3017
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    • 2018
  • Massive (large-scale) MIMO (multiple-input multiple-output) is one of the key technologies in next-generation wireless communication systems. This paper proposes a high-performance low-complexity turbo receiver for SC-FDMA (single-carrier frequency-division multiple access) based MMIMO (massive MIMO) systems. Because SC-FDMA technology has the desirable characteristics of OFDMA (orthogonal frequency division multiple access) and the low PAPR (peak-to-average power ratio) of SC transmission schemes, the 3GPP LTE (long-term evolution) has adopted it as the uplink transmission to meet the demand high data rate and low error rate performance. The complexity of computing will be increased greatly in base station with massive MIMO (MMIMO) system. In this paper, a low-complexity adaptive turbo equalization receiver based on normalized minimal symbol-error-rate for MMIMO SC-FDMA system is proposed. The proposed receiver is with low complexity than that of the conventional turbo MMSE (minimum mean square error) equalizer and is also with better bit error rate (BER) performance than that of the conventional adaptive turbo MMSE equalizer. Simulation results confirm the effectiveness of the proposed scheme.

Impacts of Non-Uniform Source on BER for SSC NOMA (Part I): Optimal MAP Receiver's Perspective

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.4
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    • pp.39-47
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    • 2021
  • Lempel-Ziv coding is one of the most famous source coding schemes. The output of this source coding is usually a non-uniform code, which requires additional source coding, such as arithmetic coding, to reduce a redundancy. However, this additional source code increases complexity and decoding latency. Thus, this paper proposes the optimal maximum a-posteriori (MAP) receiver for non-uniform source non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC). First, we derive an analytical expression of the bit-error rate (BER) for non-uniform source NOMA with SSC. Then, Monte Carlo simulations demonstrate that the BER of the optimal MAP receiver for the non-uniform source improves slightly, compared to that of the conventional receiver for the uniform source. Moreover, we also show that the BER of an approximate analytical expression is in a good agreement with the BER of Monte Carlo simulation. As a result, the proposed optimal MAP receiver for non-uniform source could be a promising scheme for NOMA with SSC, to reduce complexity and decoding latency due to additional source coding.

An MCS Level Adaptive Linear Receiver (MCS 레벨에 따른 적응 선형 수신기)

  • Lee, Kyuhee;Kim, Jaekwon;Yun, Sangkyun
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.2 no.1
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    • pp.59-64
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    • 2009
  • In this paper, a novel low complexity linear receiver is proposed that is used at the receiver of MIMO systems. Zero-forcing (ZF) and minimum mean squared error (MMSE) receivers are common linear receivers. ZF receiver is simpler than MMSE receiver from the hardware implementation perspective, howerver, MMSE shows better performance than ZF. In general, MCS level changes according to channel condition. This paper shows the benefit of choosing between MMSE and ZF according to the selected MCS level. We implement the MCS-adaptive linear receiver as hardware, and show that its complexity is comparable to the conventional MMSE receiver.

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An Adaptive Receiver Using Reduced-state Sequence Detection for the Trellis-coded CPFSK (트렐리스 부호화된 CPFSK의 적응 수신기)

  • 송형규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.6
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    • pp.746-760
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    • 1998
  • In this paper, an adaptive RSSD(reduced-state sequence detection) receiver is proposed for the purpose of reducing the complexity and decision delay of the adaptive MLSD(maximum-likelihood sequence detection) receiver in the mobile satellite channel. The RSSD receiver reconstructs the trellis with a reduced number of states. The performance degradation due to the reduced states is compensated by modifying the branch metric calculation which uses the symbols in each path memory to estimate the residual ISI(intersymbol interference) terms. The structure of the proposed adaptive RSSD is a modified RSSD utilizing a per-survivor processing as well as the symbol-aided method and a channel estimation using the tentative data sequences. The complexity and performance of the proposed adaptive RSSD are controlled by the number of system states and ISI cancelers and the inserting period of the known symbols. In spite of a suboptimal alternative receiver compared to the adaptive MLSD receiver, the proposed adaptive RSSD receiver is able to reduce the complexity significantly and track the time-varying channel fast and reliably.

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A low power, low complexity IR-UWB receiver in multipath environments and its implementation (다중 경로 환경에 적합한 저전력 저복잡도의 IR-UWB 수신기 설계 및 구현)

  • Lee, Soon-Woo;Park, Young-Jin;Kim, Kwan-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.6 s.360
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    • pp.24-30
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    • 2007
  • In this paper, an energy detection-based low power, low complexity IR-UWB receiver in multipath impulse radio channel is presented. The proposed receiver has a simple 1-bit sampler for energy detection. Also, multipath signal received from multipath impulse radio channel is amplified and envelope of the signal is detected. Then, energy detection technique using integrator by summing multipath signals in certain period is adopted to minimize the BER loss by simple energy detection. In particular, in acquisition of a sample signal, SNR is additionally improved using a digital sampler. Symbol decision using several sampled signals is performed and thus the process of symbol synchronization is significantly simplified. Also, it is effectively designed to be compatible with influences of multipath and timing error. In addition, the proposed receiver complexity is reduced using pulse decision window. The performance of the proposed receiver is simulated based on IEEE 802.15.4a channel model and the algorithms are implemented on FPGA.

Combination of Array Processing and Space-Time Coding In MC-CDMA System

  • Hung Nguyen Viet;Fernando W. A. C
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.302-309
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    • 2004
  • The transmission capacity of wireless communication systems may become dramatically high by employ multiple transmit and receive antennas with space-time coding techniques appropriate to multiple transmit antennas. For large number of transmit antennas and at high bandwidth efficiencies, the receiver may become too complex whenever correlation across transmit antennas is introduced. Reducing decoding complexity at receiver by combining array processing and space-time codes (STC) helps a communication system using STC to overcome the big obstacle that prevents it from achieving a desired high transmission rate. Multi-carrier CDMA (MC-CDMA) allows providing good performance in a channel with high inter-symbol interference. Antenna array, STC and MC-CDMA system have a similar characteristic that transmit-receive data streams are divided into sub-streams. Thus, there may be a noticeable reduction of receiver complexity when we combine them together. In this paper, the combination of array processing and STC in MC-CDMA system over slow selective-fading channel is investigated and compared with corresponding existing MC-CDMA system using STC. A refinement of this basic structure leads to a system design principle in which we have to make a trade off between transmission rate, decoding complexity, and length of spreading code to reach a given desired design goal.

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