Jaeyoon Lee

Exact and general expression for the error probability of arbitrary two-dimensional signaling with I/Q amplitude and phase unbalances

The I/Q unbalance which is generated by a non-ideal component is an inevitable physical phenomenon and leads to performance degradation when we implement a practical two-dimensional (2-D) modulation system. This paper provides an exact and general expression involving the 2-D Gaussian Q-function for the SER/BER of arbitrary 2-D signaling with I/Q amplitude and phase unbalances over an additive white Gaussian noise (AWGN) channel by using the coordinate rotation and shifting technique. Through Monte Carlo simulations we verify our expression provided here for various 16-quadrature amplitude modulation (QAM) circular constellations

Error Performance Analysis of

In this paper, we derive new exact and general expressions for the symbol error rate (SER) and bit error rate (BER) of M-ary θ-quadrature amplitude modulation (QAM) for M = 2l , I ≥ 4, based on not only square-QAM (SQAM) for M = 22l, I ≥ 2 but cross-QAM (CQAM) as well, for M = 22l+1, I ≥ 2 in additive white Gaussian noise (AWGN) and various fading channels; we also present the optimum angle and constellation of M-ary θ-QAM. Through computer simulations, we confirm the results of the theoretical analysis. Because the SER and BER expressions are provided in terms of 2-D Gaussian Q-function in AWGN and various fading channels, they will be very useful for numerical evaluations in various cases of practical interest in QAM systems.

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For a mobile projector application that can be embedded in a cellular phone, a 6-bit data driver integrated in a 0.4-inch diagonal VGA AMOLED on silicon substrate is proposed. The proposed data driver has a couple of features tailored for a microdisplay application: To be integrated with a very fine pixel pitch of 4.2 ¿m, the data driver uses a 33-degree demultiplexing scheme, thereby taking circuit area within the peripheral height of 810 ¿m. In addition, the separate gamma correction is provided to resolve the color shift problem due to the transmittance mismatch of red, green, and blue color filters. In spite of the separate gamma correction involved, the height of the data driver is not increased, because it is realized by making use of a time sharing method synchronized with the 33-degree demultiplexing.

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This paper provides a new, exact, and general expression involving 1-D and 2-D Q-functions for the bit error probability of M-ary phase-shift keying (MPSK) under additive white Gaussian noise (AWGN) and fading channels when Gray code bit mapping is employed. Regular patterns in the error probability expression of the kth bit are observed while developing the bit error rate (BER) expression. From these patterns, we then derive a new BER expression for the MPSK constellation.

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SUMMARY This paper proposes a soft-decision demapping algorithm with low computational complexity for coded 4 + 12 amplitude phase shift keying in an additive white Gaussian noise channel. The proposed algorithm requires only a few summation, subtraction, and multiplication operations to calculate the log likelihood ratio value of each bit, and shows the same error performance as a conventional max-log algorithm. Copyright

-QAM

A 4+12+16 amplitude phase shift keying (APSK) modulation outperforms other 32-APSK modulations in a nonlinear additive white Gaussian noise (AWGN) channel because of its intrinsic robustness against AM/AM and AM/PM distortions caused by the nonlinear characteristics of a high-power amplifier. Thus, this modulation scheme has been adopted in the digital video broadcasting-satellite2 European standard. And it has been considered for high rate transmission of telemetry data on deep space communications in consultative committee for space data systems which provides a forum for discussion of common problems in the development and operation of space data systems. In this paper, we present an improved bits-to-symbol mapping scheme with a better bit error rate for a 4+12+16 APSK signal in a nonlinear AWGN channel and propose a simple signal detection algorithm for the 4+12+16 APSK from the presented bit mapping.

Data driver architecture and driving scheme of AMOLED microdisplay for mobile projectors

The quadrature component unbalance generated by a non-ideal component such as an imperfect 90-degree phase shifter is an inevitable physical phenomenon and leads to performance degradation in a practical coherent M-ary phase shift keying (MPSK) transceiver. In this letter, we present an exact and general expression involving the one- and two-dimensional Gaussian Q-functions for the symbol error rate (SER) of MPSK with I/Q phase unbalance over an additive white Gaussian noise (AWGN) channel. The SER expression provided here offers a convenient way to evaluate the performance of MPSK systems for various cases of practical interest.

New BER Expression of MPSK

Telemetry link requires high data rate to transmit the multimedia data for lunar explorations in space communications. In this paper, we analyze a data rate with the modulation and channel coding schemes based on Consultative Committee for Space Data Systems (CCSDS) in S, X, Ku and Ka bands, respectively. Then, we suggests modulation and channel coding schemes to meet the link margins and have a maximum data rate for lunar explorations in telemetry links.

Soft-decision demapping algorithm with low computational complexity for coded 4 + 12 APSK

Department of Electronics and Communications Engineering Hanyang University, Seoul 133-791, KoreaRain 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).

Simple Signal Detection Algorithm for 4+12+16 APSK in Satellite and Space Communications

A 4+12+16 Amplitude Phase Shift Keying (APSK) modulation outperforms other 32-APSK modulations such as rectangular or cross 32-quadrature amplitude modulations (QAMs) which have a high peak to average power ratio that causes non-negligible amplitude modulation to amplitude modulation (AM/AM) and amplitude modulation to phase modulation (AM/PM) distortions when the signal is amplified by a high-power amplifier (HPA). Thus, this modulation scheme has been recommended as modulation scheme in the Digital Video Broadcasting-Satellite2 (DVB-S2) standard. In this paper, we present a new bits-to-symbol mapping to improve a bit error rate (BER) for a 4+12+16 APSK signal in a nonlinear satellite channel and analyze the BER.