• Title/Summary/Keyword: Bit error rate(BER)

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Wideband OFDM Communication Performance Analysis in the East Sea of Korea (대한민국 동해 해역에서 광대역 OFDM 통신 성능 분석)

  • Kwang-Young Chae;Zhao Tzan Chi;Meng Fan Jin;Min-Hyuk Cha;Ho-Jun Lee;Hak-Lim Ko;Tae-Ho Im
    • Proceedings of the Korea Information Processing Society Conference
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    • 2023.11a
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    • pp.1234-1236
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    • 2023
  • 광대역(Wideband) 통신은 신호 대역폭이 채널의 상관 대역폭(Coherence Bandwidth)를 크게 초과하는 시스템을 나타낸다. 이때, 큰 대역폭을 갖을수록 반송 주파수대역과 사용대역의 최대 및 최소 주파수 간 차이가 커지며, 통신 시스템이 겪는 채널의 주파수 선택적 페이딩 또한 커지게 된다. 수중에서 광대역 통신을 성능을 확인하기 위한 실험을 수행하였다. 실험환경으로는 송·수신기 간 수평 이격거리는 약 10m, 수직 이격거리는 약 190m로 설정하였다. 광대역 신호의 성능을 확인하기 위하여 14kHz와 30kHz의 주파수 대역과 협대역신호와의 비교를 위해 16kHz와 4kHz 대역폭 등 파라메타를 달리하여 설정하였다. x축을 Repetition Freq.와 Repetition Time의 조합으로 설정하였으며, y축을 BER(Bit Error Rate)로 성능결과를 나타내었다.

Design of Multipath Adaptive BISMO-Algorithm in the Underwater Communication (수중 통신시 다중경로 적응 BISMO (Bi-Switch Modulation)알고리즘 설계)

  • Im, Byung-Ook;Shim, Tae-Bo
    • The Journal of the Acoustical Society of Korea
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    • v.27 no.7
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    • pp.342-349
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    • 2008
  • Multipath makes clear message transfer difficult in the underwater communication. To solve this problem, we propose a new method producing proper MFSP (Modulation Frequency Shift Period) which could be obtained by calculating time delay caused by different path from a transmitter to a receiver. At the transmitter end, messages were divided according to the size of the MFSP and transmitted accordingly alternating Frequency. At the receiver end, the received messages were demodulated in order to recover the original message by the adaptive BISMO algorithm which is constructed at the algorithm design stage. Adaptive MFSP and estimated BER (Bit Error Rate) were calculated through simulation test.

A Generalized Multicarrier Communication System - Part III: Dual Symbol Superposition Block Carrier Transmission with Frequency Domain Equalization

  • Imran Ali
    • International Journal of Computer Science & Network Security
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    • v.24 no.9
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    • pp.41-49
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    • 2024
  • This paper proposes dual symbol superposition block carrier transmission with frequency domain equalization (DSS-FDE) system. This system is based upon χ-transform matrix, which is obtained by concatenation of discrete Hartley transform (DHT) matrix and discrete Fourier transform (DFT) matrices into single matrix that is remarkably sparse, so that, as it will be shown in this paper, it only has non-zero entries on its principal diagonal and one below the principle anti-diagonal, giving it shape of Latin alphabet χ. When multiplied with constellation mapped complex transmit vector, each entry of resultant vector is weighted superposition of only two entries of original vector, as opposed to all entries in conventional DFT based OFDM. Such a transmitter is close to single carrier block transmission with frequency domain equalization (SC-FDE), which is known to have no superposition. The DSS-FDE offers remarkable simplicity in transmitter design and yields great benefits in reduced complexity and low PAPR. At receiver-end, it offers the ability to harvest full diversity from multipath fading channel, full coding gain, with significant bit error rate (BER) improvement. These results will be demonstrated using both analytical expressions, as well as simulation results. As will be seen, this paper is Part III of three-paper series on alternative transforms for multicarrier communication (MC) systems.

A Simple Bit Allocation Scheme Based on Grouped Sub-Channels for V-BLAST OFDM Systems (V-BLAST OFDM 시스템을 위한 그룹화된 부채널 기반의 간단한 형태의 비트 할당 기법)

  • Park Dae-Jin;Yang Suck-Chel;Kim Jong-Won;Yoo Myung-Sik;Lee Won-Cheol;Shin Yo-An
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.7C
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    • pp.680-690
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    • 2006
  • In this paper, we present a bit allocation scheme based on grouped sub-channels for MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) systems using V-BLAST (Vertical-Bell laboratories LAyered Space-Time) detector. A fully adaptive modulation and coding scheme may provide optimal performance in the MIMO-OFDM systems, however it requires excessive feedback information. Instead, SBA (Simplified Bit Allocation) scheme for reduction of feedback overhead, which applies the same modulation and coding to all the good sub-channels, may be considered. The proposed scheme in this paper named SBA-GS (Simplified Bit Allocation based on Grouped Sub-channels) groups sub-channels and assigns the same modulation and coding to the set of selected sub-channel groups. Simulation results show that the proposed scheme achieves comparable bit error rate performance of the conventional SBA scheme, while significantly reducing the feedback overhead in multipath channels with small delay spreads.

Power Allocation Strategy for Soft-Decision-and-Forward Cooperative Communication System (연판정 후 전달 방식에 대한 전력 분배 전략)

  • Song, Kyoung-Young;Kim, Jae-Hong;No, Jong-Seon;Chung, Ha-Bong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1C
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    • pp.1-7
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    • 2010
  • In this paper, the performance of the soft-decision-and-forward (SDF) protocol in the cooperative communication network with one source, one relay, and one destination, where each node has two transmit and receive antennas, is analyzed in terms of the bit error rate (BER) obtained from the pairwise error probability (PEP). For the slow-varying Rayleigh fading channel, the optimal and suboptimal power allocation ratios are determined without feedback. The optimal power allocation can be obtained by minimizing the average PEP. For the tractability, an alternative strategy of maximizing the product SNR of direct and relay links, which we call the suboptimal power allocation, is considered. Through the numerical analysis, we show that the performance gap between the suboptimal and the optimal power allocation is negligible in the high SNR region.

A Simple Multi-rate Parallel Interference Canceller for the IMT-2000 3GPP System (IMT-2000 3GPP 시스템을 위한 간단한 다중 전송률 병렬형 간섭제거기)

  • Kim, Jin-Kyeom;Oh, Seong-Keun;Sunwoo, Myung-Hoon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.12
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    • pp.10-19
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    • 2001
  • In this paper, we propose an effective but simple multi-rate parallel interference canceller(PIC) for the international mobile telecommunications-2000(IMT-2000) 3rd generation partnership project (3GPP) system. For effective multi-rate processing, we define the basic block as one symbol period of the dedicated physical control channel(DPCCH) having the lowest data rate and common to all users. Then, decision and interference cancellation are performed at every basic block. For an asynchronous channel, we propose an advance removal scheme that removes in advance multiple access interference(MAI) due to the next blockof other users with shorter delay. Introducing a pipeline structure at a sample base, we can implement efficiently the PIC using the advance removal scheme with a minimum hardware and no extra computations. Through computer simulations, we analyze the bit error rate(BER) performance of the proposed PIC with respect to signal-to-noise ratio(SNR) and the number of users.

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Power and Offset Allocation for Spatial-Multiplexing MIMO System with Rate Adaptation for Optical Wireless Channels (다중 입출력 무선 광채널에서의 공간 다중화 기법의 적응적 전송을 위한 광출력과 오프셋 할당 기법)

  • Park, Ki-Hong;Ko, Young-Chai
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.1A
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    • pp.8-18
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    • 2011
  • Visible light communication (VLC) using optical sources which can be simultaneously utilized for illumination and communication is currently an attractive option for wireless personal area network. Improving the data rate in optical wireless communication system is challenging due to the limited bandwidth of the optical sources. In this paper, we design the singular value decomposition (SVD)-based multiplexing multi-input multi-output (MIMO) system to support two data streams in optical wireless channels. In order to improve the spectral efficiency, the rate adaptation using multi-level pulse amplitude modulation (PAM) is applied according to the channel condition and we propose the method to allocate the optical power, the offset and the size of modulation scheme theoretically under the constraints of the nonnegativity of the modulated signals, the aggregate optical power and the bit error rate (BER) requirement. The simulation results show that the proposed allocation method gives the better performance than the method to allocate the optical power equally for each data stream.

Low Complexity Iterative Detection and Decoding using an Adaptive Early Termination Scheme in MIMO system (다중 안테나 시스템에서 적응적 조기 종료를 이용한 낮은 복잡도 반복 검출 및 복호기)

  • Joung, Hyun-Sung;Choi, Kyung-Jun;Kim, Kyung-Jun;Kim, Kwang-Soon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.8C
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    • pp.522-528
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    • 2011
  • The iterative detection and decoding (IDD) has been shown to dramatically improve the bit error rate (BER) performance of the multiple-input multiple-output (MIMO) communication systems. However, these techniques require a high computational complexity since it is required to compute the soft decisions for each bit. In this paper, we show IDD comprised of sphere decoder with low-density parity check (LDPC) codes and present the tree search strategy, called a layer symbol search (LSS), to obtain soft decisions with a low computational complexity. In addition, an adaptive early termination is proposed to reduce the computational complexity during an iteration between an inner sphere decoder and an outer LDPC decoder. It is shown that the proposed approach can achieve the performance similar to an existing algorithm with 70% lower computational complexity compared to the conventional algorithms.

Effect of Multiple Antennas at a Relay Node on the Performance of Physical-Layer Network Coding in Two-Way Relay Channel (양방향 중계채널에서 중계기 다중안테나가 물리계층네트워크 코딩의 성능에 미치는 영향)

  • Park, Jeonghong;Jung, Bang Chul;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.8
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    • pp.1438-1443
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    • 2016
  • In this paper, we investigate the effect of multiple antennas at a relay node on the performance of physical-layer network coding (PNC) in the two-way relay channel (TWRC). We assume that two source nodes have a single antenna and the relay node has multiple antennas. We extend the conventional TWRC environment with a signle antenna at both relay and source nodes to the case of multiple antennas at the relay node. In particular, we consider two decoding strategies: separate decoding (SD) and direct decoding (DD). The SD decodes each packet from the two sources and performs the network coding with bit-wise exclusive OR (XOR) operation, while the DD decodes the network-coded packet from the two sources. Note that both decoding strategies are based on log-likelihood ratio (LLR) computation. It is shown that the bit error rate (BER) performance becomes significantly improved as the number of antennas at the relay node.

Optimization and Performance Analysis of Partial Multiplexing (부분 다중화의 성능 분석 및 최적화)

  • Kim, Seong Hwan;Ban, Tae Won;Jung, Bang Chul
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.7
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    • pp.1589-1596
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    • 2013
  • Recently, spectral efficiency or reliability is required to be improved in the scenario of multiple access. In this paper, we consider a scenario where two source nodes access one destination node. Different with conventional multiple access studies, in our research, a part of the allocated resource is shared by two source nodes and this scheme is called partial multiplexing. Let $R_s$ denote the ratio of the amount of the shared resource to that of the resource allocated to each user. We analyze and optimize the performance of the partial multiplexing in term of $R_s$. We show that the optimal $R_s$ to maximize the throughput is 1 or 0 based on approximated bit error rate (BER). In addition, if we set a constraint on frame error rate (FER), $R_s$ can have a value between 0 and 1. We also find the approximated $R_s$ to meet the constraint as a closed form. Partial multiplexing can be a novel multiple access scheme.