• Title/Summary/Keyword: Phase-shift keying (PSK)

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Performance of Generalized BER for Hierarchical MPSK Signal (계층적 MPSK 신호에 대한 일반화된 BER 성능)

  • Lee Jae-Yoon;Yoon Dong-Weon;Hyun Kwang-Min;Park Sang-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.9C
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    • pp.831-839
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    • 2006
  • In this paper, we present an exact and general expression involving two-dimensional Gaussian Q-functions for the bit error rate (BER) of hierarchical MPSK with I/Q phase and amplitude imbalances over an additive white Gaussian noise (AWGN) channel. First we derive a BER expression for the k-th bit of hierarchical 4, 8, 16-PSK signal constellations when Gray code bit mapping is employed. Then, from the derived k-th bit BER expression, we present the exact and general average BER expression for hierarchical MPSK with I/Q phase and amplitude imbalances. This result can readily be applied to numerical evaluation for various cases of practical interest in an I/Q unbalanced hierarchical MPSK system, because the one- and two-dimensional Gaussian Q-functions can be easily and directly computed usinB commonly available mathematical software tools.

Adaptive Coding and Modulation Scheme for Ka Band Space Communications

  • Lee, Jae-Yoon;Yoon, Dong-Weon;Lee, Woo-Ju
    • Journal of Astronomy and Space Sciences
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    • v.27 no.2
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    • pp.129-134
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    • 2010
  • Rain attenuation can cause a serious problem that an availability of space communication link on Ka band becomes low. To reduce the effect of rain attenuation on the error performance of space communications in Ka band, an adaptive coding and modulation (ACM) scheme is required. In this paper, to achieve a reliable telemetry data transmission, we propose an adaptive coding and modulation level using turbo code recommended by the consultative committee for space data systems (CCSDS) and various modulation methods (QPSK, 8PSK, 4+12 APSK, and 4+12+16 APSK) adopted in the digital video broadcasting-satellite2 (DVB-S2).

Equalizationof nonlinear digital satellite communicatio channels using a complex radial basis function network (Complex radial basis function network을 이용한 비선형 디지털 위성 통신 채널의 등화)

  • 신요안;윤병문;임영선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.9
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    • pp.2456-2469
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    • 1996
  • A digital satellite communication channel has a nonlinearity with memory due to saturation characeristis of the high poer amplifier in the satellite and transmitter/receiver linear filter used in the overall system. In this paper, we propose a complex radial basis function network(CRBFN) based adaptive equalizer for compensation of nonlinearities in digital satellite communication channels. The proposed CRBFN untilizes a complex-valued hybrid learning algorithm of k-means clustering and LMS(least mean sequare) algorithm that is an extension of Moody Darken's algorithm for real-valued data. We evaluate performance of CRBFN in terms of symbol error rates and mean squared errors nder various noise conditions for 4-PSK(phase shift keying) digital modulation schemes and compare with those of comples pth order inverse adaptive Volterra filter. The computer simulation results show that the proposed CRBFN ehibits good equalization, low computational complexity and fast learning capabilities.

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Implementation and Evaluation of the 100 Watt High Power Amplifier for Broadband Digital TV Repeater (광대역 디지털TV 중계기용 100 Watt 고출력증폭기의 구현 및 특성 측정에 관한 연구)

  • Sung, Jeon-Joong
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.5
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    • pp.575-582
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    • 2007
  • In this paper, a 100 Watt high power amplifier has been implemented and performed evaluation, which is operating at UHF band ($470\;{\sim}\;806\;MHz$) for Digital TV repeater. To achieve increase of bandwidth and high power capability, 3-way power combiner and divider of Wilkinson type was adopted. In order to measure the fabricated 100 Watt power amplifier, the estimation technique function which makes equivalent mask was used. As a result of the measurement, the existence of pilot signal is confirmed and the signal transmitted at the rated output power 100 Watt is brought out the flat feature through 6 MHz bandwidth. and it resulted that its value was less than -47 dB at the edge of radiation channel and less than -110 dB at more than 6 MHz position from channel edge.

Performance Analysis of Dual-Layer Differential Precoding Technique Using 8-PSK Constellation (8-PSK 성운을 이용하는 이중계층 차분 선부호화 기법의 성능 분석)

  • Park, Noe-Yoon;Kim, Young-Ju
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.5
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    • pp.401-408
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    • 2013
  • Dual-layer differential codebook using 8-PSK (phase shift keying) constellation as its codeword elements, is proposed for Long term evolution (LTE) and/or LTE-Advanced systems. Due to the temporal correlation of the adjacent channel matrices, the consecutive precoding matrices are likely to be similar. This approach quantize only the differential information of the channel instead of the whole channel subspace, which virtually increase the codebook size to realize more accurate quantization of the channel. Especially, the proposed codebook has the same properties of LTE release-8 codebook that is, constant modulus, complexity reduction, and nested property. The mobile station can be designed by using less expensive non-linear amplifier utilizing constant modulus property. Computer simulations show that the capacity of the proposed dual-layer codebook performs almost 1.2dB better than those of any other non-differential codebooks with the same amount of feedback information.

A study on the biorthogonally coded Q$^{2}$AM with constant envelope property (정진폭특성을 갖는 Birothogonal 부호로 부호화된 Q$^{2}$AM(Quadrature Quadrature Amplitude Modulation)에 관한 연구)

  • 박인재;심수보
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.9
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    • pp.2470-2480
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    • 1996
  • The energy efficiency and bandwidth efficiency are two important criterion in designing a modulation scheme Especially the constant envelope property must be considered as in the non-linear channel tht exit, for example in the nonlinear amplifiers for satellite repeater. The Q$^{2}$AM(Quadrature Quadrature Amplitude Modulation) is a new modulation scheme which combines the Q$^{2}$PSK(Quadrature Quadrature Phase Shift Keying) scheme which increases the signal space dimension and the QAM scheme which increases the bandwidth efficiency using the multi-level signal. The Q$^{2}$AM scheme has by far superior spectrum efficiency compared with the existing modulation schemes. Applying this scheme in the non-linear communication system increses the bandwidth efficiency but cannot envelop property. In this paper, a new system architecture is suggested which satisfies the large spectrum efficiency and constant envelope property by implementing the linear block coding prior to the Q$^{2}$AM modulation. the system has improved in performance by gaining the constant envelope and the additional coding gain. We able to observe the performance improvement of the suggested system(at BER=10$^{-5}$ ) of 4.4 dB for the 16-QAM and 0.7 dB for the Q$^{2}$PSK under the exact spectrum efficiency.

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Depth-first branch-and-bound-based decoder with low complexity (검출 복잡도를 감소 시키는 Depth-first branch and bound 알고리즘 기반 디코더)

  • Lee, Eun-Ju;Kabir, S.M.Humayun;Yoon, Gi-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2525-2532
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    • 2009
  • In this paper, a fast sphere decoder is proposed for the joint detection of phase-shift keying (PSK) signals in uncoded Vertical Bell Laboratories Layered Space Time (V-BLAST) systems. The proposed decoder, PSD, consists of preprocessing stage and search stage. The search stage of PSD relies on the depth-first branch-and-bound (BB) algorithm with "best-first" orders stored in lookup tables. Simulation results show that the PSD is able to provide the system with the maximum likelihood (ML) performance at low complexity.

Design and Performance Evaluation of Load-Modulation MIMO System Using High-Order Modulation (고차 변조를 사용하는 Load-Modulation MIMO 시스템 설계와 성능 평가)

  • Lee, Dong-Hyung;An, Changyoung;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.11
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    • pp.2121-2130
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    • 2015
  • In this paper, we analyze LM-MIMO (load-modulation multiple-input multiple-output) system with single RF chain. And then, we confirm that load modulation technique can support generation of high-order m-PSK modulation and m-QAM modulation in LM-MIMO system. Finally we evaluate performance of LM-MIMO system with load modulation. Conventional MIMO system requires a number of RF chains for expansion of MIMO dimension. A number of RF chains can cause various problems. On the other hand, although LM-MIMO system is expanded, LM-MIMO system requires single RF chain only. Therefore, LM-MIMO system has low-complexity and low power consumption. As results, we can confirm that load modulation of T-model can modulate high-order m-PSK and m-QAM singal. Also, we can confirm that $4{\times}4$ LM-MIMO system using load modulation has a similar performance to conventional $4{\times}4$ MIMO system.

CACB-Q2PSK Modulation for Efficient Bandwidth Utilization and Constant Amplitude Signal Transmission (효율적인 대역폭 이용과 정진폭 신호 전송을 위한 CACB-Q2PSK 변조)

  • Hong, Dae-Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.1
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    • pp.93-99
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    • 2008
  • In this paper, we propose new modulation schemes using the conventional CACB modulation with constant amplitude property. Also the proposed modulation schemes supports high transmission data rate by increasing the spectral efficiency. In order to obtain the high spectral efficiency, the $Q^2$PSK and CA-$Q^2$PSK are used. We explain the simplest combining modulation scheme of CACB and $Q^2$PSK (i.e., CACB-$Q^2$PSK). However, this modulation scheme cannot support the constant amplitude property. Hence the first CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK I) modulation scheme is proposed for the constant amplitude property. In the modulation scheme, the redundant constant amplitude encoding (spectral efficiency decrease) is required. Therefore, the second CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK II) modulation scheme is proposed retaining the constant amplitude and the spectral efficiency. Computer simulations show that the proposed CACB-CA-$Q^2$PSK II is the efficient modulation scheme.

Design of the PHY Structure of a Voice and Data Transceiver with Security (보안성을 갖는 음성 및 데이터 트랜시버의 물리 계층 구조 설계)

  • Eun, Chang-Soo;Lom, Sun-Min;Lee, Kyoung-Min
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.10 s.352
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    • pp.46-54
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    • 2006
  • In this paper, we propose a digital transceiver that can overcome the problems which current analog transceivers have. For the proposed transceiver, we assumed a frequency resource that consists of discrete and narrow channels. We also assumed that person-to-group, group-to-group, as well as person-to-person, voice and data communications with moderate security should be devisedand the data rate is 1 Mbps with simultaneous voice and data. Frequency hewing spread spectrum (FH-SS) and differential 8-PSK (D8PSK) were adopted for security reasons and bandwidth constraints, and for the reduction of implementation complexity, respectively. For the carrier and the symbol timing recovery, the structure of the preamble was proposed based on the IEEE 802.11 FHSS frame format to improve detection probability. The computer simulation results and power budget analysis implies that the proposed system can be usedin simple wireless communications in place of such as analog walkie-talkies.