Abstract — We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Data is encoded by a channel code and the encoded data is split into � streams that are simultaneously transmitted using � transmit antennas. The received signal at each receive antenna is a linear superposition of the � transmitted signals perturbed by noise. We derive performance criteria for designing such codes under the assumption that the fading is slow and frequency nonselective. Performance is shown to be determined by matrices constructed from pairs of distinct code sequences. The minimum rank among these matrices quantifies the diversity gain, while the minimum determinant of these matrices quantifies the coding gain. The results are then extended to fast fading channels. The design criteria are used to design trellis codes for high data rate wireless communication. The encoding/decoding complexity of these codes is comparable to trellis codes employed in practice over Gaussian channels. The codes constructed here provide the best tradeoff between data rate, diversity advantage, and trellis complexity. Simulation results are provided for 4 and 8 PSK signal sets with data rates of 2 and 3 bits/symbol, demonstrating excellent performance that is within 2–3 dB of the outage capacity for these channels using only 64 state encoders.

We analyze the performance of direct-sequence spread spectrum multiple access (DS/SSMA) systems, which use trellis coding with asymmetric phase shift keying (PSK) modulation. By designing the signal constellation to be asymmetric, we obtain a performance gain for the DS/SSMA system over the systems using the traditional symmetric signal constellation. Bit error probability analysis of the proposed system is carried out for some cases. Examples are given to show the performance gain due to the asymmetry of the signal constellation. # 1998 Elsevier Science B.V. All rights reserved. Zusammenfassung Wir untersuchen die Eigenschaften von DS/SSMA (Direct Access Spread Spectrum Multiple Access) Systemen, welche eine Trellis Kodierung mit asymmetrischer PSK Modulierung benutzten. Durch die asymmetrische Gestaltung der Signalkonstellation erhalten wir verbesserte Eigenschaften des DS/SSMA Systems verglichen mit Systemen, die die traditionelle, symmetrische Signalkonstellation benutzen. Fu r einige Systeme wird eine Analyse der Bit-Fehlerwahrscheinlichkeiten fu r das vorgeschlagene System durchgefu hrt. Beispiele, die die Verbesserung aufgrund der asymmetrischen Signalkonstallation belegen, werden angegeben. # 1998 Elsevier Science B.V. All rights reserved.

The design of good TCM schemes matched to ISI channels requires that analytical performance bounds are also available. In this paper, starting from an application of the unionBhattacharyya bound, upper-bounds for the performance of the theoretically optimum combined Symbol-by-Symbol (SbS) Abend-Fritchman like equalizer and decoder are presented for the first time in literature. The combined detector acts on the distorted version of the TCM signal received at the output of a channel impaired by (known) ISI and AWGN. On the basis of these bounds a novel simple criterion for the design of TCMs optimally matched to any assigned ISI-corrupted transmission channel is then derived and its application to some actual testchannels is illustrated.

In this paper, we show that several coding schemes, and in particular turbo encoding, dramatically improve the performance of a noncoherently detected frequency shift-keying modulation with correlated signals. The APP decoding scheme based on bit-by-bit decisions proves to be better than a classical block decisions decoding scheme when the bit mapping is not optimized. Moreover, the choice of the FSK modulation tone spacing is important. Finally, high latency and low latency systems are compared. I. Introduction Frequency Shift Keying (FSK) modulation with orthogonal signals is commonly used on noncoherent channels and exhibits an excellent robustness [1]. However, it suffers from its poor spectral efficiency. When the tone spacing of the modulation is chosen to be smaller than unity, the transmitted signals are correlated and the spectral efficiency increases. The price to pay for this bandwidth reduction is a degradation in the noncoherent detector performance. It is shown that sev...

A novel adaptive coherent receiver for TCM signals transmitted over randomly time-variant frequencyselective fast-fading wireless links is presented. Its main feature is that the three different tasks of channelestimation, equalization and decoding are jointly carried out in an optimal way. The last two operations are jointly accomplished by a Symbol-by-Symbol (SbS) AbendFritchman like detector [3, Sect.6.6] which delivers both hard-decisions and suitably defined soft-output statistics. The latter directly feed a non-linear Kalman-type estimator for channel tracking. Using the more informative soft-statistics in place of usual hard statistics for channel estimation constitutes the novel attractive feature of the proposed receiver; in this way, the channel estimator is able to fully exploit the coding redundancy so to enhance the tracking capability.

In this contribution we present some analytical performance bounds that point out the key parameters dominating the performance of symbol-by-symbol combined-type maximum a posteriori equalizers/decoders for trellis-coded modulation (TCM) transmissions over fast-faded intersymbol-interference-impaired Rayleigh-channels with diversity reception. Guidelines are also provided for the design of good TCM codes matched to the statistical features of the multipath transmission links and application examples are developed that support the actual effectiveness of the presented results.

The performance Symbol-by-Symbol (SbS) AbendFritchman like combined equalizers/decoders [5] performing diversity reception and coherent detection of Trellis-CodedModulated (TCM) is analyzed for the case of fast time-variant, ISI-corrupted, Rayleigh-faded data-channels. New upperbounds for the resulting decoding error probability are derived and a related novel criterion for the design of TCM schemes optimally matched to the statistical properties of the transmission channel is also presented.