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The paper describes a digital circuit technique to process directly bit-stream signals from sigmadelta modulation based analogue-to-digital converters and the application of the technique to communication systems. The newly developed adder and multiplier are fundamental processing circuit modules. Using the fundamental modules and up/down counters, other(More)
In recent year, to achieve a high data rate and high quality multimedia service in wireless communication systems, orthogonal frequency division multiplexing (OFDM) is attractive and widely studied. Moreover, orthogonal frequency division multiple access (OFDMA) which is combined OFDM and frequency division multiple access (FDMA) provides each user with a(More)
In the mobile radio environment, signals are usually impaired by fading and multipath delay phenomenon. In such channels, severe fading of the signal amplitude and inter-symbol-interference (ISI) due to the frequency selectivity of the channel cause an unacceptable degradation of error performance. Orthogonal frequency division multiplexing (OFDM) is an(More)
Recently time-frequency interferometry (TFI)-OFDM has been proposed as a channel identification scheme. TFI-OFDM system can multiplex the same impulse response in twice on the time domain without overlapping to each other. In this case, the required pilot signal is only one. Moreover, by averaging of these impulse responses, the ac-curated channel impulse(More)
This paper describes piecewise linear circuits operating directly on first-order multi-level and second-order binary sigma-delta modulated signals. The sigma-delta modulated signal sequences contain subsequences which reflect whether the inputs to sigma-delta modulators are positive or negative. We build circuits performing absolute operation with detectors(More)
—In a long-term evolution (LTE)-Advanced, single carrier frequency division multiple access (SC-FDMA) has been adapted in a uplink. The advantage of SC-FDMA can be achieved a low peak average power ratio (PAPR). In recent years, cooperative communications are widely studied. Cooperative communications can be obtained the space diversity as multiple input(More)
In recent years, cooperative communications are widely studied. Cooperative communications can obtain the space diversity as multiple-input multiple-output (MIMO) systems. In cooperative communications, the relay method is important as decode-and-forward (DF) and decode-amplify-forward (DAF). The multi-relay cooperative communications can improve the system(More)