centroid, 19, 25, 30 circular displacement, 102 code convolutional, 36, 58 Elias, 256 Gallager-vanVoorhis, 255 Golomb, 218, 254 Golomb–Rice, 188 Levenstein, 256 monotonic, 254 prefix-free, 239 terminated convolutional, 37 trellis, 38 unary, 254 zero-tail terminated convolutional, 37 codebook, 26, 27 adaptive, 154 adaptive gain, 155 stochastic, 156 stochastic gain, 156 codec ACELP, 158 code exci...

This paper describes development of adaptive filter algorithm for an Underwater Acoustic Telemetry (UWAT) system for communication between the off shore underwater device (UD) and on-shore communication system. In this system, FSK modulation and de-modulation techniques are used with centre frequency of 38 KHz with baud rate of 300Hz. Adaptive filter algorithm has been developed to compensate t...

The quality of the current waveform generated by a current controlled, voltage source shunt active power filter depends basically on three factors: (i) The reference signal being generated; (ii) the modulation method used and (iii) the switching frequency of the PWM modulator. A new adaptive hysteresis band modulation method is proposed. In this paper, the periodical sampling constant hysteresi...

Multi carrier CDMA (MC-CDMA) combines the CDMA and OFDM technologies together and potentially offers the advantages of both the technologies. In frequency selective channel, the sub-carrier experiences different amplitude and phase. In frequency domain spreading, the frequency diversity is employed but the best of different sub-carrier conditions are not fully exploited. In MC-CDMA the performa...

The performance of an orthogonal frequency-division multiplexing (OFDM) system can be significantly increased by using adaptive modulation and transmit diversity. An accurate estimate of the channel, however, is required at the transmitter to realize this benefit. Due to the time-varying nature of the channel, this estimate may be outdated by the time it is used for detection. This results in a...

In this paper, an adaptive quadrature amplitude modulation (AQAM) scheme for an equalized system over a selective channel is investigated. To reduce intersymbol interference (ISI), a minimum-mean-squarederror decision feedback equalizer (MMSE-DFE) with an unbiased decision rule is used. In order to select the appropriate modulation mode, the receiver estimates the MSE at the equalizer output. T...

This paper discusses the application of adaptive modulation and adaptive rate turbo coding to orthogonal frequency-division multiplexing (OFDM), to increase throughput on the time and frequency selective channel. The adaptive turbo code scheme is based on a subband adaptive method, and compares two adaptive systems: a conventional approach where a separate turbo code is used for each subband, a...

Recently, the authors introduced a novel algorithm for long range prediction of flat fading channels that can reliably predict future fading coefficients far beyond the coherence time. This prediction capability provides enabling technology for power and bandwidth efficient adaptive modulation and coding methods. In this paper, we extend our results to the Direct Sequence Code Division Multiple...

In this paper, adaptive coding and modulation techniques are envisaged in a satellite mobile system adopting the WCDMA air interface. The physical layer performance, in terms of bit error rate, for several coding rates and modulation formats are reported. Preliminary results of the feasibility for OFDM techniques in the satellite channel are also shown.

We investigated the spatial summation effect on pedestals with difference luminance. The targets were luminance modulation defined by Gaussian functions. The size of the Gaussian spot was determined by the scale parameter (standard deviation, σ) which ranged from 0.13 to 1.04. The local luminance pedestal (2 radius) had mean luminance ranged from 2.9 to 29cd/m. The no-pedestal condition had a m...