Christian B. Schlegel, Lance C. Pérez · 2004
It has become apparent over the past few decades that while there are strict limits on the power and bandwidth resources, the complexity of systems could steadily be increased to obtain efficiencies ever closer to these limits. One very successful method of reducing the power requirements without increase in the requirements on bandwidth was introduced by Gottfried Ungerboeck, subsequently termed trellis-coded modulation (TCM). We start this chapter with an illustrative example of this intriguing method of combining coding and modulation. Later, we consider group-trellis codes, the mapping function, construction of codes, lattices, rotational invariance, and geometric uniformity.
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Stephen G. Wilson · 2003
Abstract Trellis‐coded modulation (TCM) is an important practical means of achieving several decibels in link efficiency on Gaussian channels, without bandwidth expansion, and is now a component of numerous wireline and wireless standards. This article surveys the important principles in the design and analysis of such encoders, provides tabulations of best codes, and illustrates with discussion of two standards employing TCM.
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N. Benvenuto, Giovanni Cherubini · 2002
This chapter contains sections titled: Linear TCM for One- and Two-dimensional Signal Sets Multidimensional TCM Rotationally Invariant TCM Schemes Bibliography
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Martin H. Weik · 2000
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Patrick Robertson, Thomas Wörz · elib (German Aerospace Center) · 1996
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Fabian Schuh, Andreas Schenk, Johannes B. Huber · arXiv (Cornell University) · 2013
In classic trellis-coded modulation (TCM) signal constellations of twice the cardinality are applied when compared to an uncoded transmission enabling transmission of one bit of redundancy per PAM-symbol, i.e., rates of $\frac{K}{K+1}$ when $2^{K+1}$ denotes the cardinality of the signal constellation. In order to support different rates, multi-dimensional (i.e., $\mathcal{D}$-dimensional) constellations had been proposed by means of combining subsequent one- or two-dimensional modulation steps, resulting in TCM-schemes with $\frac{1}{\mathcal{D}}$ bit redundancy per real dimension. In contrast, in this paper we propose to perform rate adjustment for TCM by means of puncturing the convolutional code (CC) on which a TCM-scheme is based on. It is shown, that due to the nontrivial mapping of the output symbols of the CC to signal points in the case of puncturing, a modification of the corresponding Viterbi-decoder algorithm and an optimization of the CC and the puncturing scheme are necessary.
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Mahmoud Abdelaziz, T. Aaron Gulliver · IEEE Access · 2019
Ternary trellis coded modulation (TTCM) is introduced. This combines triangular signal constellations with ternary convolutional codes. The performance of TTCM is presented and compared with binary trellis coded modulation (BTCM) which employs square quadrature amplitude modulation (SQAM) and binary convolutional coding. Ternary set partitioning (TSP) is used for TTCM, and binary-to-ternary conversion is determined that is suitable for TTCM. A construction for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -ary triangular QAM (TQAM) which is compatible with TSP is presented. The performance of BTCM is compared with that of TTCM.
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Gottfried Ungerboeck · 1987
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C.R. Nassar · Elsevier eBooks · 2001
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Eyal Katz, G.L. Stüber · 2002
Systematic trellis-coded modulation (STCM) is a novel approach to coded modulation, which enables symbol-by-symbol detection of trellis-coded data. A set of design rules, which guarantees nonzero coding gain, and codes with asymptotic coding gains of 3.0-5.4 dB are presented. STCM is well suited for operation in a dual-mode receiver. During normal operation the receiver uses a sequence estimation algorithm such as MLSE or SSE. When the channel introduces severe distortion, as is the case during a deep fade, the decoder switches to a systematic decoding algorithm, which is simple to implement, and guarantees BER performance that is better than uncoded modulation. The authors demonstrate the performance of various STCM codes with a dual-mode receiver on multipath fading channels.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
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W.J. Blackert, S. G. Wilson · 1996
Turbo codes have excited the coding community with the promise of performing near channel capacity by using an iterative decoding technique that relies upon simple constituent codes. However, since the original turbo codes are low rate codes, a significant bandwidth penalty can be incurred by systems which utilize turbo codes. Since the constituent codes that make up turbo codes are convolutional codes, a natural extension of the turbo concept, in order to improve bandwidth efficiency, is its application to Trellis Coded Modulation (TCM) systems. This paper will discuss the conditions under which encoders with parallel transitions can be used as constituent codes in Turbo TCM systems and present results to compare systems with and without parallel transition constituent encoders. 1 Introduction Turbo coding, introduced in [1], is a coding technique that uses an iterative decoding algorithm to give performance near channel capacity. Since Turbo codes use convolutional codes as their co...
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Encyclopedia of Ocean Engineering · 2022
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Divsalar, Dariush, Simon, Marvin K. · NASA Technical Reports Server (NASA)
A technique for designing trellis codes to minimize bit error performance for a fading channel. The invention provides a criteria which may be used in the design of such codes which is significantly different from that used for average white Gaussian noise channels. The method of multiple trellis coded modulation of the present invention comprises the steps of: (a) coding b bits of input data into s intermediate outputs; (b) grouping said s intermediate outputs into k groups of s.sub.i intermediate outputs each where the summation of all s.sub.i,s is equal to s and k is equal to at least 2; (c) mapping each of said k groups of intermediate outputs into one of a plurality of symbols in accordance with a plurality of modulation schemes, one for each group such that the first group is mapped in accordance with a first modulation scheme and the second group is mapped in accordance with a second modulation scheme; and (d) outputting each of said symbols to provide k output symbols for each b bits of input data.
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Ruey-Yi Wei, Mao‐Chao Lin · IEEE Communications Letters · 1998
We propose a method to construct noncoherent-coded modulation (NCM) by modifying the conventional trellis-coded modulation (TCM) as proposed by Ungerboeck (1982). The error performance of the modified TCM using noncoherent decoding can approach that of the conventional TCM using coherent decoding for additive white Gaussian noise.
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Sergio Benedetto, D. Divsalar, G. Montorsi et al. · 2002
In this paper, we propose a new solution to parallel concatenation of trellis codes with multilevel amplitude/phase modulations and a suitable bit by bit iterative decoding structure. Examples are given for throughput 2 and 4 bits/sec/Hz with 8 PSK, 16 QAM, and 64 QAM modulations. For parallel concatenated trellis codes in the examples, rate 2/3 and 4/5, 8, and 16-state binary convolutional codes with Ungerboeck mapping by set partitioning (natural mapping), a reordered mapping, and Gray code mapping are used. The performance of these codes is within 1 dB from the Shannon limit at a bit error probability of 10/sup -7/ for a given throughput, which outperforms the performance of all codes reported in the past for the same throughput.
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Călin Vlădeanu · 2012
In this paper, a turbo trellis-coded spatial modulation (TTCSM) transmission scheme is proposed. In trellis-coded spatial modulation (TCSM) scheme, the information bits used to select the transmit antenna index are encoded. In order to increase the performances of the TCSM scheme, a parallel concatenated encoding scheme can be used. Therefore, the TCSM scheme is modified by introducing two identical convolutional encoders, with proper interleaving and puncturing, as in the case of conventional parallel turbo trellis-coded modulation (TTCM) scheme. The punctured TTCSM scheme, using the symbol-by-symbol log-MAP iterative decoding algorithm in the receiver, is developed. The bit error rate (BER) is estimated by simulations for PSK-TCSM transmissions over stationary Rayleigh, Rician, and spatially correlated (SC) fading channels with additive white Gaussian noise (AWGN). As an example, a scheme with a spectral efficiency of 3b/s/Hz using eight transmit and receive antennas and a BPSK signal is considered. It is shown that the TTCSM scheme offers a coding gain over the corresponding non-iterative TCSM scheme of at least 6 dB for the Rayleigh fading channel, 3 dB for the Rician channel, and 2 dB for the SC fading channel, respectively.
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Honary, Bahram · Lancaster EPrints (Lancaster University) · 1995
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Shalini Periyalwar, S. Fleisher, Shouxing Qu · 1991
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Sezgin Sen · Istanbul Technical University Academic Open Archive (Istanbul Technical University) · 2011
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011
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Paul K. Gray · 1999
this memory [23]. Now, it has been observed that that the output of a Viterbi decoder can be modeled as a two state Markov Chain [24--26]. A new test for this is developed here for this hypothesis and it is shown that this is also true for TCM schemes. Other authors [27, 28] have proposed decoding algorithms for the Gilbert--Elliott channel, a time-varying channel which can be modeled with a two state Markov Chain, which preserves the capacity of the channel with memory. The combination of these two concepts leads to the proposal of a new, low complexity decoding algorithm for concatenated codes, based upon the modeling of the inner trellis decoder as a Gilbert--Elliott channel. Bounds calculations for this algorithm suggested that improvements in performance of up to 1 dB were possible. However, due to limitations of the decision feedback decoder used as the outer decoder, and the extreme nature of the Markov Chain model of the inner decoder (one state has an error rate of 0.5), none of this performance gain could be achieved in practice. It appeared that the only way to realise the promised gain was to use a soft-output algorithm for the inner Introduction decoder. However, in this case the algorithm becomes the same as a single iteration of the SCCC decoding algorithm and there is no reduction in complexity. Having examined reduced complexity decoding algorithms for concatenated codes and being led back to SCCC, the second half of this dissertation concentrates on ways of improving the performance of SCCC and iteratively decoded serially concatenated trellis coded modulation (referred to here as SCTCM). In Chapter 4 some background information is presented for both iteratively decoded PCCC and SCCC, including the iterated MAP decoding algorithms. Then the performan...
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