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Topic: Trellis modulation


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In the News (Sun 15 Nov 09)

  
  Trellis modulation Totally Explained
In telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme which allows highly efficient transmission of information over band-limited channels such as telephone lines.
The name "trellis" was coined because a state diagram of the technique, when drawn on paper closely resembles the trellis lattice used in rose gardens.
A flurry of research activity ensued, and by 1984, the International Telecommunication Union published modem standards utilizing trellis modulation to achieve rates of 19.2 kbit/s and higher.
trellis_modulation.totallyexplained.com   (688 words)

  
  Modulation - Wikipedia, the free encyclopedia
Modulation is the process of varying a carrier signal in order to use that signal to convey information.
A device that performs modulation is known as a modulator and a device that performs the inverse operation of demodulation is known as a demodulator.
In digital modulation, the changes in the signal are chosen from a fixed list (the modulation alphabet) each entry of which conveys a different possible piece of information (a symbol).
en.wikipedia.org /wiki/Modulation   (676 words)

  
 Trellis - Wikipedia, the free encyclopedia
Look up trellis in Wiktionary, the free dictionary.
Trellis of North Wales, a fictional radio correspondent in I'm Sorry I Haven't a Clue
This is a disambiguation page: a list of articles associated with the same title.
en.wikipedia.org /wiki/Trellis   (105 words)

  
 Encyclopedia :: encyclopedia : Amplitude modulation   (Site not responding. Last check: 2007-10-06)
Amplitude modulation (AM) is a form of modulation in which the amplitude of a carrier wave is varied in direct proportion to that of a modulating signal.
Each sideband is equal in bandwidth to that of the modulating signal and is a mirror image of the other.
This is single-sideband modulation, widely used in amateur radio due to its efficient use of both power and bandwidth.
www.hallencyclopedia.com /Amplitude_modulation   (1256 words)

  
 Trellis modulation - Wikipedia, the free encyclopedia
In telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme which allows highly efficient transmission of information over band-limited channels such as telephone lines.
The name "trellis" was coined because a state diagram of the technique, when drawn on paper closely resembles the trellis lattice used in rose gardens.
A flurry of research activity ensued, and by 1984, the International Telecommunication Union published modem standards utilizing trellis modulation to achieve rates of 19.2 kbit/s and higher.
en.wikipedia.org /wiki/Trellis_modulation   (599 words)

  
 Modulation
Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information.
There are several reasons to modulate a signal before transmission in a medium.
Pass the modulated signal on for further processing, such as filtering and channel-coding, before transmission.
www.brainyencyclopedia.com /encyclopedia/m/mo/modulation.html   (782 words)

  
 Trellis Coded modulation tutorial - TCM
The coding is an digital function and modulation which is an analog function are done separately and independently in most modulations.
In modulated signals, both types of distances are presnt.
First when the data is in baseband digital form, we have Hamming distance between adjacent words (bit sets), and then when the signal is mapped to symbols, we have Euclidean distance between the symbols (the small packets of analog carrier).
www.complextoreal.com /tcm.html   (366 words)

  
 Serial-Turbo-Trellis-Coded Modulation With Rate-1 Inner Code
These codes are applicable to such high-level modulations as octonary phase-shift keying (8PSK) and 16-state quadrature amplitude modulation (16QAM); the signal product obtained by applying one of these codes to one of these modulations is denoted, generally, as "serially concatenated trellis-coded modulation" ("SCTCM").
The suboptimal iterative decoding structure for such a code is modular, and consists of a set of concatenated decoding modules — one for each constituent code — connected through an interleaver identical to the one in the encoder side.
The lower part of the figure is a block diagram of an SCTCM encoder for an M-point two-dimensional constellation that would enable the use of a decoder of lower complexity.
www.nasatech.com /Briefs/Jan04/NPO20878.html   (1061 words)

  
 Jeffrey O. Coleman - EE590A Trellis Coded Modulation   (Site not responding. Last check: 2007-10-06)
(The trellis itself is a very group-theoretic creature as well.) Along the way, we develop a dynamic-programming algorithm (the Viterbi algorithm) for the receiver that leads to the lowest possible probability of making an error in the determination of the transmitted data sequence.
Typically students design our first trellis code, develop the idea of set partitioning for labeling a trellis with outputs, and derive the Viterbi (or other) algorithm for maximum-likelihood sequence estimation in the receiver.
Students will be expected to complete (and thoroughly document) a team computer-simulation project in which they implement a general trellis coder and Viterbi decoder for testing trellis codes of their own design.
www.ece.mtu.edu /faculty/jeffc/courses/EE590As96.html   (490 words)

  
 Modem and method for 8 dimensional trellis code modulation - Patent 4873701
It is known in the prior art that encoding the data at the transmitter of a modem using a convolutional encoder and performing maximum likelihood (Viterbi) decoding at the receiver decreases the error rate of the modem at a given signal-to-noise ratio (SNR), assuming that the major impairment is Gaussian noise.
The trellis encoder (18) adds one check bit to the 16 data bits and the resulting 17 bits are mapped into an 8D point consisting of a sequence of four 2D signal points each selected from a 20-point 2D constellation.
The trellis record for i* points to the record for the previous best state leading to i* which points to the record for its previous best state, etc. The decoded 20 Z bits are found at the end of the trellis path.
www.freepatentsonline.com /4873701.html   (5921 words)

  
 Serial-Turbo-Trellis-Coded Modulation With Rate-1 Inner Code NASA Tech Briefs - Find Articles
The suboptimal iterative decoding structure for such a code is modular, and consists of a set of concatenated decoding modules - one for each constituent code - connected through an interleaver identical to the one in the encoder side.
This is because the number of transitions per state for the inner TCM is 2^sup 2b+1^ and so the number of edges in the trellis section of the decoder would have to equal to 2^sup 2b+1^ × the number of states.
Because the inner code does not have redundancy, it is useless by itself; however, the combination of the inner and outer codes with the interleaver results in very powerful code.
www.findarticles.com /p/articles/mi_qa3957/is_200401/ai_n9382380   (985 words)

  
 Welcome to EE359 Adaptive Modulation Home Page
It is shown that for trellis codes, adapting both the rate and transmit power achieves a coding gain of 3DB relative to uncoded adaptive MQAM; for turbo codes, adapting both the encoder and the transmit power achieves performance within 3dB of the fading channel capacity.
This scheme was shown in [1] to have an 11 dB gap from the Shannon capacity of the Rayleigh fading channel.
For example, in an eight-state trellis code we require a minimum square constellation size of 16 to represent all eight cosets; in a four-state trellis code we require a minimum square constellation size of 4 to represent all four cosets.
www.stanford.edu /~mmren   (2211 words)

  
 Amazon.ca: Constellation Shaping, Nonlinear Precoding, and Trellis Coding for Voiceband Telephone Channel Modems : With ...   (Site not responding. Last check: 2007-10-06)
It is essential for researchers in modulation and coding for voiceband telephone line modems; signal constellation design; nonlinear precoding for modems; and trellis coding.The author presents the theory behind the new modulation and coding techniques included in ITU-T Recommendation V.34.
The combination of shell mapping, precoding, and trellis coding arranged in a feedback loop that was selected for Recommendation V.34 is the topic of Chapter 10.
It is also suitable as a text for an advanced course in modulation and coding at the graduate level.
www.amazon.ca /exec/obidos/ASIN/1402070063   (742 words)

  
 System and method for I/Q trellis coded modulation (US6158041)
In one embodiment, the trellis coded modulation technique optimizes code performance for a given implementation cost.
Also, this trellis coded modulation technique provides optimal performance in the context of periodic symbol deletion, whether this deletion is due to intentional puncturing, the use of interleaving in the presence of fading, or the use of interleaving in an OFDM system used to communicate across a frequency-selective channel.
wherein said convolutional code is chosen to optimize performance when said trellis coded modulation symbols are subject to periodic deletion.
www.delphion.com /details?pn10=US06158041   (387 words)

  
 Efficient Performance Computations for Trellis-Coded Modulation
However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
In this letter, the algorithm given by Rouanne and Costello for the computation of the distance spectrum is improved for trellis-coded modulation schemes having uncoded bits, i.e., for trellis diagrams having parallel paths.
Zehavi and J. Wolf, "On the performance evaluation of trellis codes," IEEE Trans.
www.comsoc.org /comm/private/1999/jun/796_47comm06-rajab.html   (179 words)

  
 [No title]
In TCM, the bandwidth expansion is not required because it uses the same symbol rate and power spectrum; the differences are the introduction of a redundancy bit and the use of a constellation with double points.
In the decoder, a Hamming distance is used as a cost function to determine output in the maximum likelihood Viterbi decoder.
Using the relationship between the delay states and the path state in the Trellis tree of the code, a pre-calculated Hamming distances are stored in a look-up table.
library.usask.ca /theses/available/etd-08212003-161938   (321 words)

  
 Trellis Coded Modulation
Their dense constellation makes it relatively easy for a slight degree of phase jitter or amplitude spike to result in a received constellation point offset a sufficient amount from its ideal position to be misinterpreted, resulting in a multiple-bit error (each symbol in error results in a number of bits in error).
The solution to this problem was to incorporate forward error correction (FEC), which in modems is called trellis coding, since the receiver uses the trellis decision tree associated with Viterbi decoding.
Using trellis coding, the error rate can be reduced by three orders of magnitude (from 1 in 10 to 1 in 10
www.argospress.com /Resources/modems/trellcodmodula.htm   (222 words)

  
 WSL - Publications
Katz, E. and Stüber, G. L., ''Sequential Sequence Estimation for Trellis-coded Modulation on Multipath Fading ISI Channels,'' IEEE Transactions on Communications, vol.
Narayanan, K. and Stüber, G. L., ''Performance of Trellis Coded CPM with Iterative Demodulation and Decoding,'' IEEE Global Telecommunications Conference, Communication Theory Mini-conference, pp.
Katz, E. and Stüber, G. L., ''Systematic Trellis-coded Modulation for Multipath Fading ISI Channels,'' 13th Phoenix Conference on Computers and Communications, pp.
users.ece.gatech.edu /~stuber/publications.html   (5397 words)

  
 Trellis-Coded Modulation with Bit Interleaving and Iterative Decoding
Divsalar and M. Simon, "The design of trellis coded modulation for MPSK for fading channels: Performance criteria," IEEE Trans.
Chan and D. Haccoun, "Performance of punctured trellis coded modulation over fading channels," in Proc.
Wilson and Y. Leung, "Trellis-coded phase modulation on Rayleigh channels," in Proc.
www.comsoc.org /sac/private/1999/apr/715_17sac04-li.html   (558 words)

  
 Cross-Correlated Trellis-Coded Quadrature Modulation
While the previously developed TCM techniques afford the bandwidth efficiency inherent in multilevel modulation, less attention was given, in the development of those techniques, to achieving high levels of spectral containment as quantified, for example, by keeping out-of-band power levels low to minimize adjacent-channel interference.
Considering only quadrature modulations, the innovative aspect of the development of XTCQM lies in a focus on the spectral occupancy of the transmitted signal, along with careful attention to a desirable constant-envelope property and to the power efficiency of the demodulation/decoding operation at the receiver.
In XTCQM, a cross-correlation and a suitable waveform mapping are introduced into the in-phase (I) and quadrature (Q) baseband signals transmitted on quadrature carriers, in such a way as to provide a high level of spectral efficiency while also maintaining high power efficiency and a constant or pseudo-constant envelope.
www.nasatech.com /Briefs/Aug00/NPO20532.html   (412 words)

  
 Citebase - Golden Space-Time Trellis Coded Modulation   (Site not responding. Last check: 2007-10-06)
The inner code is the Golden code citeGolden05 and the outer code is a trellis code.
Set partitioning of the Golden code is designed specifically to increase the minimum determinant.
The branches of the outer trellis code are labeled with these partitions.
citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:cs/0604063   (165 words)

  
 About lattice
A wood lattice consists of diagonal or vertical and horizontal strips of wood (laths) cris-crossing to make a grille like pattern.
Lattice is suitable for trellis or as decorative sections in fences, handrails, arbors, pergolas, garden or deck privacy screens, windbreaks etc.
The two most common lattice profiles are diagonal and square.
www.buildeazy.com /trellis.html   (345 words)

  
 Dariush Divsalar: Trellis coded modulation for 4800 to 9600 bps transmission over a fading satellite channel (SuDoc NAS ...
Dariush Divsalar, "Trellis coded modulation for 4800 to 9600 bps transmission over a fading satellite channel (SuDoc NAS 1.26:177159)", National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology National Technical Information Service, distributor, 1986.
Other subject areas related to Trellis coded modulation for 4800 to 9600 bps transmission over a fading satellite channel (SuDoc NAS 1.26:177159) (possibly beyond the scope of this Modems Glossary) include: Bandwidth, Bit error rate, Coding, Communication, Constraints, Fading, Ground stations, Land mobile satellite service, Modulation, Phase shift keying, Transmission circuits.
To propose other terms to be added to these glossaries, please contact us.
www.argospress.com /Resources/modems/book-B00010PF90.htm   (256 words)

  
 Serially Concatenated Trellis Coded Modulation - Gray (ResearchIndex)   (Site not responding. Last check: 2007-10-06)
Gray "Serially concatenated trellis coded modulation", PhD Dissertation, Univ. of South Australia, submitted, Aug. 1998.
11 Trellis--coded multidimensional phase modulation (context) - Pietrobon, Deng et al.
3 Coding and modulation techniques for high speed data service..
citeseer.ist.psu.edu /234814.html   (426 words)

  
 ECS EPrints Service - Combined Trellis-Coded Modulation and Blind Turbo Equalisation
In this contribution, the Per-Survivor Processing (PSP) based blind turbo equalization is combined with various coded modulation schemes, which employ combined modulation and channel coding techniques.
Explicitly, a BER comparable to that of a trained turbo equaliser is attained at the cost of a modest complexity increase.
EPrints is free software developed by the University of Southampton to facilitate Open Access to research.
eprints.ecs.soton.ac.uk /5978   (189 words)

  
 William P. Osborne: High-speed architecture for the decoding of trellis-coded modulation semi-annual status report, ...
William P. Osborne, "High-speed architecture for the decoding of trellis-coded modulation semi-annual status report, period covered January 1992 - July 1992 (SuDoc NAS 1.26:191374)", New Mexico State University, Electrical and Computer Engineering National Aeronautics and Space Administration National Technical Information Service, distributor, 1992.
Other subject areas related to High-speed architecture for the decoding of trellis-coded modulation semi-annual status report, period covered January 1992 - July 1992 (SuDoc NAS 1.26:191374) (possibly beyond the scope of this Modems Glossary) include: Computer architecture, Modulation (Electronics).
Please contact Argos Press to request permission to reproduce, broadcast, adapt and communicate our content (including this glossary entry on William P. Osborne: High-speed architecture for the decoding of trellis-coded modulation semi-annual status report, period covered January 1992 - July 1992 (SuDoc NAS 1.26:191374)).
www.argospress.com /Resources/modems/book-B00010G8WS.htm   (268 words)

  
 References for Trellis Coded Modulation   (Site not responding. Last check: 2007-10-06)
IT-28, pp.55-67, Jan. 1982 Trellis-coded modulation with redundant signal sets -Part I:Introduction, -G. Ungerboeck, -IEEE Communications Magazine, vol.
25, no. 2, Feb, 1987 Digital Communications -John G. Proakis, The design of trellis coded MPSK for fading channels: Performance criteria, -D. Divsalar and M. Simon, -IEEE Trans.
1004-1012, Sept. 1988 Tight bounds on the error probability of coded modulation schemes in Rayleigh fading channels, -S. Slimane and T. Le-Ngoc, -IEEE Trans.
www.fulton.asu.edu /~trccomm/meetings/tcm_reference.html   (101 words)

  
 Joint Source Channel Coding Using Arithmetic Codes and Trellis Coded Modulation   (Site not responding. Last check: 2007-10-06)
Abstract: Previous work has indicated that using an arithmetic encoder with reserved probability space can pro vide powerful error detection and error correction when used with a sequential decoding algorithm.
In this work a Trellis Coded Modulation scheme is used to provide a convenient tree for a list decoding algorithm.
Simulations on A WGN channels with bit err or rates in the range of 10^{-3} to 10^{-1.5} show significant pack et recovery rates even for the poorest channels.
csdl.computer.org /comp/proceedings/dcc/2001/1031/00/10310302abs.htm   (190 words)

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