scispace - formally typeset
Search or ask a question

Showing papers on "Phase-shift keying published in 1992"


Journal ArticleDOI
TL;DR: The results suggest that on a Rayleigh channel, the standard trellis codes may not be the correct approach for improving the reliability of the communication channel.
Abstract: A suboptimal trellis coding approach based on the concept of combining a good convolutional code and bit interleavers is presented. The aim is to improve the reliability of digital radio communication over a fading channel. It is shown that over a Rayleigh channel and for a fixed code complexity the proposed system is superior to the baseline system. Its performance is analyzed using the generalized R/sub o/ and the upper bound on the bit error rate. The results suggest that on a Rayleigh channel, the standard trellis codes may not be the correct approach for improving the reliability of the communication channel. The discussion is restricted to a rate 2/3 coded system with 8-PSK modulation. >

1,074 citations


Patent
Michel Fattouche1, Hatim Zagloul1
31 Mar 1992
TL;DR: In this article, a first frame of information is multiplexed over a number of wideband frequency bands at a first transceiver, and the information transmitted to a second transceiver.
Abstract: A method for allowing a number of wireless transceivers to exchange information (data, voice or video) with each other. A first frame of information is multiplexed over a number of wideband frequency bands at a first transceiver, and the information transmitted to a second transceiver. The information is received and processed at the second transceiver. The information is differentially encoded using phase shift keying. In addition, after a pre-selected time interval, the first transceiver may transmit again. During the preselected time interval, the second transceiver may exchange information with another transceiver in a time duplex fashion. The processing of the signal at the second transceiver may include estimating the phase differential of the transmitted signal and pre-distorting the transmitted signal. A transceiver includes an encoder for encoding information, a wideband frequency division multiplexer for multiplexing the information onto wideband frequency voice channels, and a local oscillator for upconverting the multiplexed information. The apparatus may include a processor for applying a Fourier transform to the multiplexed information to bring the information into the time domain for transmission.

489 citations


Journal ArticleDOI
TL;DR: In this paper, the advantages of the millimeter-wave band usage for personal communication systems are briefly described and several fiber-optic link architectures, including one using a combination of direct laser modulation and indirect (external) optical modulation, are outlined with respect to signal transmission at millimeterwave frequencies.
Abstract: System concepts for millimeter-wave personal communication systems and the advantages of millimeter-wave band usage are briefly described. Demonstration of broadband millimeter-wave subcarrier transmission concepts over fiber-optic links is performed. Several fiber-optic link architectures, including one using a combination of direct laser modulation and indirect (external) optical modulation, are outlined with respect to signal transmission at millimeter-wave frequencies. Several configurations are experimentally investigated using 70-MHz, 300-MHz, and 26-GHz subcarriers which transmit either FM or QPSK data signals. Additionally, the use of optical MMIC technology, which can result in the design of compact and cost-effective optical receivers, is described with respect to personal communication radio base station equipment. MMIC HEMTs operating as photodetectors are newly characterized in terms of digital and analog signal reception with excellent performance being observed. >

279 citations


Journal ArticleDOI
TL;DR: This work presents an exact expression for the pairwise error event probability of trellis-coded modulation (TCM) transmitted over Rayleigh-fading channels, which includes phase shift keying and multilevel quadrature amplitude modulation (QAM) codes, as well as coherent and partially coherent codes.
Abstract: This work presents an exact expression for the pairwise error event probability of trellis-coded modulation (TCM) transmitted over Rayleigh-fading channels. It includes phase shift keying (PSK) and multilevel quadrature amplitude modulation (QAM) codes, as well as coherent and partially coherent (e.g. differential, pilot tone, etc.) detection. Due to the form of the exact pairwise error event probabilities, this calculation technique cannot be used with the transfer function technique to obtain an upper (union) bound on the overall bit error probability. For this reason, the authors estimate the bit error probability by considering only a small number of short error events. Through simulations, they found that the estimation is usually very accurate at high signal-to-noise ratios but not as accurate at lower signal-to-noise ratios. They study several coded modulation schemes this way. Among the results are the fact that TCM provides significant improvement in the error floor when detected differentially, and an asymmetry in the pairwise error event probability for 16 QAM. >

275 citations


Journal ArticleDOI
TL;DR: A novel transmitter diversity scheme that generates forced fading to improve the performance of channel coding is proposed and investigated and it is shown that excessively long interleaving is not required by the use of transmitter diversity.
Abstract: A novel transmitter diversity scheme that generates forced fading to improve the performance of channel coding is proposed and investigated. Since the required phase sweeping frequency is much smaller than the transmission bit rate, bandwidth expansion is negligible. A sinusoidal phase sweeping function Delta Theta sin(2 pi f/sub H/t) is employed in laboratory experiments using 32 kbit/s quarternary differential phase shift keying (QDPSK) with differential detection and BCH(23,12) code. It is shown that Delta Theta =200 degrees and f/sub H/=67 Hz can be used when m (interleaving depth)=10 b. Hence, excessively long interleaving is not required by the use of transmitter diversity. Under very slow Rayleigh fading (f/sub D/=1 Hz), a measured improvement of 4.8 dB is obtained at a word error rate of 10/sup -2/ without receiver diversity. Applications include paging systems that require very simple receivers. >

192 citations


Journal ArticleDOI
TL;DR: An analog model describing signal amplitude and phase variations on shadowed satellite mobile channels and an M-state Markov chain is applied to represent environment parameter variations show close agreement with measurements.
Abstract: An analog model describing signal amplitude and phase variations on shadowed satellite mobile channels is proposed. A linear combination of log-normal, Rayleigh, and Rice models is used to describe signal variations over an area with constant environment attributes while an M-state Markov chain is applied to represent environment parameter variations. Channel parameters are evaluated from the experimental data and utilized to verify a simulation model. Results, presented in the form of signal waveforms, probability density functions, fade durations, and average bit and block error rates, show close agreement with measurements. >

159 citations


Patent
02 Jun 1992
TL;DR: In this paper, a radio system is designed as to allow each of a pair of transceivers to assess the quality of the link and to modify the signal constellation accordingly, and each transceiver monitors the quality by assessing the strength of the received signal, or the bit error rate, or both.
Abstract: A radio system is so designed as to allow each of a pair of transceivers to assess the quality of the link, and to modify the signal constellation accordingly. Each transceiver monitors the quality of the channel by assessing the strength of the received signal, or the bit error rate, or both. The system is specifically adapted to time division duplex (TDD) transmission over fast fading channel. In each block of data, the first bit is a QPSK (4QAM) signal, which indicates which constellation is to be used.

157 citations


Journal ArticleDOI
TL;DR: It is shown that multiple-symbol differential detection is a very effective strategy for eliminating the irreducible error floor associated with a conventional differential detector.
Abstract: The error performance of multiple-symbol differential detection of uncoded QPSK signals transmitted over correlated Rayleigh fading channels is studied. The optimal detector is presented, along with an exact expression for the corresponding pairwise error event probability. It is shown that multiple-symbol differential detection is a very effective strategy for eliminating the irreducible error floor associated with a conventional differential detector. In all of the cases investigated, a detector with an observation interval as small as two symbols is sufficient for this purpose. It is also found that the error performance of a multiple-symbol differential detector is not sensitive to the mismatch between the decoding metric and the channel fading statistics. >

156 citations


Journal ArticleDOI
TL;DR: A differentially coherent detection scheme with improved bit error rate (BER) performance is presented for differentially encoded binary and quaternary phase shift keying (PSK) modulation.
Abstract: A differentially coherent detection scheme with improved bit error rate (BER) performance is presented for differentially encoded binary and quaternary phase shift keying (PSK) modulation. The improvement is based on using L symbol detectors with delays of 1, 2, . . ., L symbol periods and on feeding back detected PSK symbols. Exact formulas for the bit error probability are derived for the case that correct symbols are fed back. The effect of symbol errors in the feedback path on the BER is determined by computer simulations. >

146 citations


Journal ArticleDOI
F. Derr1
TL;DR: In this paper, a phase diversity receiver, called an intradyne receiver, with an orthogonal electrical demodulation is proposed to keep the signal processing bandwidth low, which is mostly due to the low local laser power and the influence of the receiver input noise.
Abstract: A receiver concept based on optical quadrature phase-shift keying (QPSK) and a digital realization of synchronous demodulation including phase synchronization is presented. To keep the signal processing bandwidth low a phase diversity receiver, called an intradyne receiver, with an orthogonal electrical demodulation is proposed. Basic principles of the synchronous orthogonal and digital demodulation are described. After the evaluation of the shot noise limit some aspects of the digital phase-locked loop (PLL) are presented. In a 100-Mb/s transmission system a receiver sensitivity of -51.6 dBm has been measured. The loss in relation to the shot noise limit of -66.3 dBm (18 photons/b) is mostly due to the low local laser power and the influence of the receiver input noise. >

143 citations


Patent
12 Mar 1992
TL;DR: In this article, a low cost spread spectrum modulator for BPSK, or Binary Phase Shift Keying capable of outputting the high modulation rate and suppressed carrier output needed in spread spectrum systems was presented.
Abstract: A low cost spread spectrum modulator for BPSK, or Binary Phase Shift Keying capable of outputting the high modulation rate and suppressed carrier output needed in spread spectrum systems. The present invention provides high quality BPSK modulation without the double balance mixers as required in the prior art, thereby dispensing with the necessity of complex transistor/potentiometer or diode/transformer arrangements. The present invention provides BPSK modulation utilizing only one transformer (A), which can be adjusted for carrier suppression and two transistors (C, D), FET's, or digital logic gates or the like, allowing the present system to be driven from low power CMOS logic levels, yet producing eight db of gain. The present invention may also be utilized as a frequency multiplier, with the utilization of the appropriately high frequency transistor, FET, digital logic gate, or the like.

Journal ArticleDOI
TL;DR: By employing the technique known as the matched filter bound, the authors derive analytical expressions for the distribution and average of the bit-error-rate in an ideal space diversity mobile radio receiver, giving insight into the relative benefits of antenna diversity and wideband transmission over the mobile radio channel.
Abstract: By employing the technique known as the matched filter bound, the authors derive analytical expressions for the distribution and average of the bit-error-rate in an ideal space diversity mobile radio receiver. Each diversity branch receives from a frequency-selective Rayleigh fading channel of arbitrary delay profile, and is subjected to additive Gaussian noise of arbitrary spectral shape. Numerical results calculated from the analytical expressions give insight into the relative benefits of antenna diversity and wideband transmission over the mobile radio channel. >

Journal ArticleDOI
TL;DR: The author presents uncoded and coded performance results for noncoherent M-ary frequency-shift keying (MFSK) and differentially coherent binary phase-shiftkeying (DPSK) in a slow nonselective Nakagami-m (1960) fading channel.
Abstract: The author presents uncoded and coded performance results for noncoherent M-ary frequency-shift keying (MFSK) and differentially coherent binary phase-shift keying (DPSK) in a slow nonselective Nakagami-m (1960) fading channel. He gives simple expressions for the asymptotic slopes of probability of bit error for large signal-to-noise ratio and shows that the effective order of diversity compared to an uncoded Rayleigh channel is the product of two parameters, one for the channel and one for the code. He also compares the uncoded Nakagami-m results to those of the Rician channel in order to show performance differences between these two generalized fading channel models. >

Journal ArticleDOI
TL;DR: The results indicate that 16-APSK can be considered as a potential candidate for spectrally efficient digital transmission over practical mobile fading channels.
Abstract: The error probability for fully differential 16-APSK in a Rayleigh fading channel has been evaluated theoretically and through the use of extensive computer simulation. The optimum ring ratio and detection thresholds have been determined and the results indicate that 16-APSK can be considered as a potential candidate for spectrally efficient digital transmission over practical mobile fading channels.

Journal ArticleDOI
TL;DR: A system employing SADD phase estimation, trellis-coded modulation, interleaving, and amplitude weighting within the Viterbi decoder yielded the best BER performance on the shadowed MSAT channel considered.
Abstract: The symbol-aided (SA) synchronization concept developed by Moher and Lodge (1989) is applied to the MSAT channel modeled with a shadowed Rician process. Simulation data demonstrate that it can track the severe phase jitter encountered on the fading channel free of the false lock which plagues conventional techniques. The algorithm multiplexes known symbols into the data stream, establishing an absolute reference free of decision errors that is used to estimate the fading phase. An improvement to the SA algorithm which extracts phase information from the data-bearing symbols is proposed. It is found that the new technique is more effective for larger K. The improved algorithm is referred to as symbol-aided plus decision-directed (SADD) phase estimation. A system employing SADD phase estimation, trellis-coded modulation, interleaving, and amplitude weighting within the Viterbi decoder yielded the best BER performance on the shadowed MSAT channel considered. >

Journal ArticleDOI
TL;DR: The use of QAM for mobile radio applications is considered and it is shown that this form of multilevel modulation can offer an attractive solution to current bandwidth restrictions in microcellular networks.
Abstract: With spectral congestion increasing, and plans announced to dramatically increase the number of mobile telephone users over the coming decade, many approaches are being considered to reduce the bandwidth requirements of each user. One approach is the use of quadrature amplitude modulation (QAM), a particular form of multilevel modulation where each symbol contains several bits of information. The use of QAM for mobile radio applications is considered and it is shown that this form of multilevel modulation can offer an attractive solution to current bandwidth restrictions in microcellular networks. An advanced variable-rate system is also considered and hardware development of a QAM modem discussed.

Patent
23 Jul 1992
TL;DR: In this paper, a trellis coded QAM for communicating information is proposed, which is based on codes for QPSK modulation and symbol error-correcting coding (SEC).
Abstract: Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM for communicating information Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used In an encoder, an N-bit QAM constellation pattern is divided into four subsets, each including N/4 symbol points of the constellation pattern A two-bit QPSK codeword is assigned to each of the four subsets A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm Part of the symbol is then encoded with an inner code that comprises a rate 1/2 trellis encoding algorithm to provide a QPSK codeword, which is mapped with the remaining bits of the symbol to provide a modulation function The remaining bits correlate the symbol with one of the symbol points included in the subset defined by the QPSK codeword A receiver is provided to recover information from the modulation function

Journal ArticleDOI
TL;DR: In this paper, the authors derived an exact and easily computed expression for the pairwise error event probability of interleaved coded PSK modulations transmitted over channels with correlated Rayleigh flat fading and additive white Gaussian noise.
Abstract: The authors derive an exact and easily computed expression for the pairwise error event probability of interleaved coded PSK modulations transmitted over channels with correlated Rayleigh flat fading and additive white Gaussian noise. Both coherent and differential detection are considered. In the case of coded DPSK, it is found that full interleaving does not necessarily provide the best error performance, especially when the fading is relatively fast and when the autocorrelation function of the channel fading process exhibits an oscillating behavior. For coherent detection or for differential detection in channels with relatively slow fading, increasing the interleaving depth always improves the error performance. In these cases, an interleaving depth equivalent to one-fifth to one-quarter the duration of a fade cycle is almost as good as full interleaving. >

Journal ArticleDOI
TL;DR: In this paper, the performance of four carrier-synchronization techniques suitable for both homodyne and heterodyne detection of optical quadriphase-shift keying was investigated through analysis and simulation.
Abstract: Through analysis and simulation, the authors investigated the performance of four carrier-synchronization techniques suitable for both homodyne and heterodyne detection of optical quadriphase-shift keying: the discrete-time decision-directed loop, the analog decision-directed loop, the Costas quadriphase loop, and the fourth-power phase-locked loop. Accounting for shot noise, laser phase noise, and feedback delay, they optimize the loop natural frequency and specify laser-linewidth requirements. The performance discrepancy between the best and worst of these loops is found to be small; accounting for inherent loop delays only, the linewidth requirements range from Delta vT >

Patent
Tatsuya Ishikawa1, Noboru Taga1
30 Jul 1992
TL;DR: In this article, a phase detector obtains phase difference data between the phase expressed by the first and second calculation outputs and a predetermined phase and quadrant data of the phase, which is used for a PLL.
Abstract: A QPSK modulated wave is inputted to an in-phase detector and an orthogonal detector. The detected components are converted to substantially a base band, and each component is digital-converted by A/D converters. Each digital component is spectrum-shaped by digital LPFs. The outputs of digital LPFs are inputted to a complex multiplier and calculated by use of first and second reproduction carriers and expressed as first and second calculation outputs, and inputted to a phase detector. The phase detector obtains phase difference data between the phase expressed by the first and second calculation outputs and a predetermined phase and quadrant data of the phase. The phase difference data is used for a PLL. The phase difference data is is inputted to a frequency error detection circuit detecting a frequency error. The frequency error output is smoothed by a filter of an AFC loop, and used as a control signal controlling the oscillation frequency of the local oscillation unit. If the frequency error is large, the frequency error detection circuit controls the AFC loop to be in an operation state and the PLL loop and the PLL loop to be in a fixed state. If the frequency error is small, the frequency error detection circuit contains the control state of the AFC loop and switches the PLL loop to be the operation state.

Journal ArticleDOI
TL;DR: In this paper, the average bit error rate (BER) performances of 16 square/star QAM and 16 CPSK/DPSK under Rayleigh fading are theoretically analyzed and compared.
Abstract: The average bit error rate (BER) performances of 16 square/star QAM and 16 CPSK/DPSK under Rayleigh fading are theoretically analysed and compared. 16 star QAM is inferior to 16 square QAM, which achieves the best performance, by ∼4 dB in the required average Eb/N0; however, when compared with differentially encoded square QAM, the performance inferiority is less than 2 dB.

Journal ArticleDOI
TL;DR: The authors derive close upper and lower bounds on the average bit error probability for hybrid direct-sequence/slow-frequency-hopped spread-spectrum multiple-access systems with noncoherent DPSK demodulation using predetection diversity in conjunction with interleaved channel coding.
Abstract: The authors derive close upper and lower bounds on the average bit error probability for hybrid direct-sequence/slow-frequency-hopped spread-spectrum multiple-access (DS/SFH-SSMA) systems with noncoherent DPSK demodulation, using predetection diversity (selection combining and equal gain combining) in conjunction with interleaved channel coding (Hamming

Journal ArticleDOI
TL;DR: New upper bounds on the error performance of coded systems for Rician channels are presented and allow for complex bounds using the fine structure of the code, for simpler bounds similar to those on memoryless channels and finally for a random coding bound using the cutoff rate of the channel.
Abstract: New upper bounds on the error performance of coded systems for Rician channels are presented. The fading channels need not be fully interleaved to obtain meaningful performance results. These bounds hold for coherent, differentially coherent and noncoherent demodulation of binary signals. They provide a useful analytical approach to the evaluation of the error performance of convolutional or block coding and they may be generalized to M-ary signals and trellis modulation. The approach allows for complex bounds using the fine structure of the code, for simpler bounds similar to those on memoryless channels and finally for a random coding bound using the cutoff rate of the channel. The analysis thus permits a step by step evaluation of coded error performances for Rician-fading channels. >

Journal ArticleDOI
TL;DR: A decision-directed, digitally implemented carrier synchronizer for channels with both frequency and phase uncertainty is presented and its derivatives are analyzed with respect to the achievable carrier acquisition time and the resulting bit error probability.
Abstract: A decision-directed, digitally implemented carrier synchronizer for channels with both frequency and phase uncertainty is presented. This combined algorithm and its derivatives are analyzed with respect to the achievable carrier acquisition time and the resulting bit error probability. For certain data rates (approximately 50 MSps or less), this algorithm can be implemented using CMOS gate array technology. As examples BPSK and QPSK modulation formats are studied herein and compared to their differentially coherent counterparts of DPSK and DQPSK. >

Journal ArticleDOI
TL;DR: A study of minimum mean-square error (MMSE) diversity combining for wide-band digital cellular radio, designed to combat intersymbol interference (ISI) caused by frequency selective fading is outlined.
Abstract: A study of minimum mean-square error (MMSE) diversity combining for wide-band digital cellular radio, designed to combat intersymbol interference (ISI) caused by frequency selective fading is outlined. The systems analyzed use binary phase-shift keying (BPSK), quarternary phase-shift keying (QPSK) or 16-level quadrature amplitude modulation (16-QAM) with cosine rolloff spectral shaping, and space diversity with selection, maximal ratio or MMSE combining. A set of performance curves is presented for selected combining schemes showing the influence of the following system parameters: the diversity order (1 to 4); the cosine rolloff factor; the power delay spectrum (with its associated delay spread); the signal-to-interference ratio; and the number of modulation levels (2, 4 and 16). >

Proceedings ArticleDOI
10 May 1992
TL;DR: In this paper, an adaptive direct conversion transmitter in which adjacent channel power measurements are used to simultaneously compensate for both power amplifier (PA) nonlinearity and quadrature modulator (QM) errors is presented.
Abstract: An adaptive direct conversion transmitter in which adjacent channel power measurements are used to simultaneously compensate for both power amplifier (PA) nonlinearity and quadrature modulator (QM) errors is presented. The measured results are presented to identify the sensitivity of the quadrature modulator's parameters (gain and phase imbalance, DC offsets) to temperature and the local oscillator frequency. An analysis of the system is given which details the relationship between the adjacent channel power and the PA nonlinearity and the QM errors; this result explains how a simple algorithm may be used to adjust the parameters based on a scalar measurement of the adjacent channel power. Simulation and measured results of a system using offset QPSK modulation with adaptive PD and QM correction are given. >

Journal ArticleDOI
TL;DR: The authors investigate the bit-error-rate (BER) performance of hybrid direct-sequence/slow-frequency-hopped spread-spectrum multiple-access systems operating over a multipath Rician-fading channel and consider both phase-shift-keying modulation with coherent demodulation and differential phase- shifts with noncoherent demodulations.
Abstract: The authors investigate the bit-error-rate (BER) performance of hybrid direct-sequence/slow-frequency-hopped spread-spectrum multiple-access (DS/SFH-SSMA) systems operating over a multipath Rician-fading channel (which models indoor radio propagation in factories). They consider both phase-shift-keying (PSK) modulation with coherent demodulation and differential phase-shift-keying (DPSK) modulation with noncoherent demodulation. Predetection multipath diversity (maximal ratio combining for coherent reception and equal gain combining for noncoherent reception) and simple interleaved channel coding are employed for improving the BER performance. The BER of both coherent and noncoherent hybrid systems is obtained using a Gaussian interference approximation. >

Journal ArticleDOI
TL;DR: In this article, the linewidth requirements for BPSK, QPSK and MSK homodyne/heterodyne detection systems are obtained by applying the Pade approximation in evaluating the receivers' performance.
Abstract: The spectral spreads of quadrature-phase-shift-keying (QPSK) modulation and minimum shift keying (MSK) modulation are narrower than those of other kinds of modulation with the same bit rate. Therefore, they are attractive for systems limited by electrical bandwidth and available optical frequency. The synchronous demodulation offers better sensitivity than differential demodulation. However, the propagation delay time of the phase locked loop affects the performance of synchronous detection systems. Therefore, linewidth requirements while considering the loop delay time must be considered in designing these systems. The linewidth requirements for BPSK, QPSK, and MSK homodyne/heterodyne detection systems are obtained by applying the Pade approximation in evaluating the receivers' performance. A change in the power penalty with respect to the change in these values is also obtained. >

Journal ArticleDOI
TL;DR: In this paper, the authors investigate the performance of a scheme in conjunction with convolutional coding and soft-decision Viterbi decoding via a semianalytical technique based on the method of moments.
Abstract: Compound strategies of equalization and space diversity in the form of an optimum baseband combiner are attractive for wideband time division multiple access (TDMA) portable communication radio links in order to combat dispersive fading and cochannel interference. The authors investigate the performance of such a scheme in conjunction with convolutional coding and soft-decision Viterbi decoding via a semianalytical technique based on the method of moments. Such an approach avoids a Gaussian characterization of interference and yields results for both ideal interleaving and no interleaving. With dual space diversity, three taps per forward filter, and a data rate of 10 Mb/s, it is shown that, although a third space diversity branch remains preferable in terms of performance, channel coding can be a viable alternative, particularly in terms of outage rate, to increasing the space diversity order, even in the absence of interleaving, provided the signal-to-interference ratio is sufficiently high. >

Journal ArticleDOI
TL;DR: Three short-block data detection techniques based on linear, nonlinear decision-directed, and maximum likelihood estimation principles are investigated and performance is presented for BPSK and QPSK type signaling using a Rayleigh fading channel model with severe time-dispersion.
Abstract: The objective is reliable digital communications over fading channels with severe time-dispersion. Three short-block data detection techniques based on linear, nonlinear decision-directed, and maximum likelihood estimation principles are investigated. Short alternating blocks of data and training symbols are used. The training blocks are useful for both channel tracking and data block detection. In contrast to the recursive symbol-to-symbol equalization approaches usually employed, each data block is detected as a unit. Previous restrictions imposed on short-block detection schemes have been removed, resulting in reduced complexity algorithms and higher throughput efficiency. Performance is presented for BPSK and QPSK type signaling using a Rayleigh fading channel model with severe time-dispersion. >