• Title/Summary/Keyword: BPSK

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Implementation of an indoor wireless modem using direct sequence spectrum technology (직접시퀀스 대역 확산 방식을 이용한 실내 무선 모뎀의 구현)

  • 박병훈;김호준;황금찬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.9A
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    • pp.2141-2152
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    • 1998
  • In this paper, we design and implement an indoor wireless modem using small signal of ISM band regulation, which can tranceive reliable data streams. We use direct sequence spead spectrum (DS-SS) signaling with synchronous BPSK and QPSK modulation, convolutional coding with viterbi decoding. The radio frequency module uses frequency devision duplexing in 900 MHz band, and the digital module is implemented with FPGAs for the purpose fo ASIC design. The perfomrance of our own acquistion and tracking circuit consisting digital matched filter and decision logic is proved by experiments, and the possibility of file transfer at indoor environment with the entrie system that the modem is connected the PC through RS-232C port is verified.

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An Improvement on FFT-Based Digital Implementation Algorithm for MC-CDMA Systems (MC-CDMA 시스템을 위한 FFT 기반의 디지털 구현 알고리즘 개선)

  • 김만제;나성주;신요안
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7A
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    • pp.1005-1015
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    • 1999
  • This paper is concerned with an improvement on IFFT (inverse fast Fourier transform) and FFT based baseband digital implementation algorithm for BPSK (binary phase shift keying)-modulated MC-CDMA (multicarrier-code division multiple access) systems, that is functionally equivalent to the conventional implementation algorithm, while reducing computational complexity and bandwidth requirement. We also derive an equalizer structure for the proposed implementation algorithm. The proposed algorithm is based on a variant of FFT algorithm that utilizes a N/2-point FFT/IFFT for simultaneous transformation and reconstruction of two N/2-point real signals. The computer simulations under additive white Gaussian noise channels and frequency selective fading channels using equal gain combiner and maximal ratio combiner diversities, demonstrate the performance of the proposed algorithm.

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Design of RFID System Using Spread Spectrum (스프레드스펙트럼통신방식을 적용한 RFID시스템 설계)

  • Baek, Seung-Jae
    • The Journal of the Korea Contents Association
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    • v.7 no.3
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    • pp.42-49
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    • 2007
  • This paper implements RFID(radio-frequency identification)System to which the system was apply SS(Spread Spectrum) method. The system designed by using the algorithm for microprocessor with PLL of the receiver, PN spread, modulation and demodulation of the transceiver, and transistor amplifier for the output of stabilized BPSK (Binary Phase Shift Keying) signal. furthermore, it reduced the interference of the signal by designing the micro-strip narrow banded patch antenna, which is convenient for printing and producing, and decreased the volume of filter size in the system. It is also designed for the lower powered system with the possible application to UHF band of $860\sim930MHz$ for the international standard frequency band, which is the quota share of RFID distribution system.

Adaptive Resource Allocation Algorithm with GTD in Downlink MU-MIMO Channel (다중 사용자 다중 안테나 하향링크 채널에서 GTD 기반의 적응적인 자원 할당 기법)

  • Choi, Seung-Kyu;Lee, Chung-Yong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.11
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    • pp.53-59
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    • 2011
  • We propose an adaptive resource allocation algorithm with generalized triangular decomposition scheme in downlink multi-user multiple-input-multiple-output channel to maximize the system throughput when we adopt the modulation scheme such as BPSK, QPSK, 16QAM, and 64QAM. The proposed scheme also considers an bit-error-rate performance as well as system throughput while performing resource allocation. We present simulation results to show that the proposed scheme achieves the system throughput up to 2bit difference by capacity and has better BER performance than SVD based resource allocation scheme in all SNR regions.

LPI Performance Analysis of GMSK Modulation Scheme (GMSK 변조 방식의 LPI 성능 분석)

  • 유형만;정병기;유흥균
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.4
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    • pp.594-599
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    • 2001
  • The symbol rate which is the main feature of NRZ information signal is detected by DAM (Delay-And-Multiplier) receiver. It is important for secure communication to reduce the normalized output SNR which is calculated at the DAM output as a measure of detectability. In this paper, we use the signal which is modulated by the class of MSK modulation schemes as the input signal of the DAM receiver for analyzing LPI performance and the GMSK(BT=0.3) used in GSM system is highlighted. Consequently, GMSK which has better bandwidth efficiency than other modulation schemes(BPSK, QPSK, OQPSK, and MSK) has better LPI performance compared with other ones. To compare the performances of each modulation scheme fairly, the transmitted powers of each system are set to be same within useful bandwidth.

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A Study of VLC Channel Modeling using user Location Environment (사용자 위치 기반의 VLC 채널 모델 도출에 관한 연구)

  • Lee, Jung-Hoon;Cha, Jae-Sang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.10B
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    • pp.1240-1245
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    • 2011
  • In this paper, channel modeling and analysis of wireless visible light communication(VLC) were studied in indoor circumstance. Photons emitted from LED straightly moved and navigated within indoor, after that a part of photons reached on PD via LOS(Line Of Sight) or NLOS(None Line Of Sight). These received signals had characteristics of delay profile and attenuation, which was multiple-path fading. In this paper, computer simulation of VLC channel was executed under the condition that two LEDs were used for transmitter and three PDs were located at different positions of the 20*8*2.3m sized indoor. BER performance simulation was excuted based on the characteristics of each VLC channel.

Analysis of Intersymbol Interference due to Overlap m Overlap-Based DM-BPSK CSS Systems (오버랩 기반 DM-BPSK CSS 시스템에서 오버랩 횟수에 따른 심볼 간 간섭 분석)

  • Kim, Jun-Hwan;Lee, Young-Po;Song, Iick-Ho;Yoon, Seok-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.2C
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    • pp.99-104
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    • 2011
  • The chirp spread spectrum (CSS) technique spreads the data signal over a frequency bandwidth wider than minimum required bandwidth. By using time overlapping, the bit rate in CSS can be increased. However, for reliable transmission of data signal, the intersymbol interference (ISI) due to overlap should be analyzed. In this paper, the relation between the degree of overlap and ISI is analyzed in direct modulation binary phase shift keying CSS systems. In some cases, the overlap does not incur ISI at all and the ISI fluctuates or monotonically increases as the number of overlaps changes. It is also shown that the simulation results closely agree with the analytic results.

Performance Comparison of Baseband Modulation Methods in DS-CDMA Communication System (대역확산통신시스템에서 기저대역변조 방식에 따른 성능 비교)

  • 이성민;김환우
    • Journal of the Korea Institute of Military Science and Technology
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    • v.5 no.1
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    • pp.24-36
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    • 2002
  • It is important to use frequency resource effectively to support much more users, to maximize the DS-CDMA system performance. In this paper, we use MPSK, QAM, MFSK and PR coder as a baseband modulation method for DS-CDMA system. Increasing user's number, we compare the performance of each system using different baseband modulation method, by expecting BER performance. BPSK has generally good performance, in case of low power operation of terminal 8FSK has excellent performance relatively, PR has excellent performance when high power operation of terminal and also good for situation of excessive user's number. QAM is not suitable for DS-CDMA system.

Analysis of PSK modulation signal generation circuit using hybrid coupler and delay line (Hybrid coupler와 delay line을 사용한 PSK 변조 신호발생 회로해석)

  • Ban, Kyung-Sig;Kim, Young-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.2
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    • pp.227-232
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    • 2009
  • The simple PSK signal generation method using a quadrature hybrid coupler and reflection coefficient elements was analyzed in this paper. The PSK modulation signal with a constant constellation is generated by reflection coefficient from 90o hybrid coupler output ports, the high-mode PSK signal is also generated by the hybrid structure of coupler, delay line and power combiner. The BPSK signal is simply generated by a 90o hybrid coupler and reflection elements, and QPSK with 90o phase constellation is generated by additional delay line and power combiner. By simulation results, the generated PSK signals by the proposed circuit get good modulation spectra within 3o phase error.

Time-Division-Multiplexing Tertiary Offset Carrier Modulation for GNSS

  • Cho, Sangjae;Kim, Taeseon;Kong, Seung-Hyun
    • Journal of Positioning, Navigation, and Timing
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    • v.11 no.3
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    • pp.147-156
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    • 2022
  • In this paper, we propose Time-Division-Multiplexing Tertiary Offset Carrier (TDMTOC), a novel GNSS modulation based on Tertiary Offset Carrier (TOC) modulation. The TDMTOC modulation multiplexes two three-level signals (i.e., -1, 0, and 1) while crossing over time, and is a type of TOC modulation designed specifically for signal multiplexing. The proposed modulation generates TDMTOC subcarriers of two different phases by simply combining two Binary Offset Carrier (BOC) subcarriers by addition or subtraction. TDMTOC has better correlation and spectral properties than conventional BPSK, BOC, and MBOC modulation techniques, and has good power and spectral efficiency since it can multiplex signals without power loss similar to time division multiplexing. To prove this, we introduce the multiplexing process of TDMTOC, and compare TDMTOC with Binary Phase Shift Keying (BPSK), BOC, Composite BOC (CBOC), and Time Multiplexed BOC (TMBOC) that are currently serviced in GNSS by simulations of various aspects. Through the simulation results, we prove that TDMTOC has better correlation property than modulations currently used in GNSS, less intersystem interference due to its wide spectrum property, and robustness in multipath and noise channel environments.