Journal ArticleDOI
Channel coding with multilevel/phase signals
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TLDR
A coding technique is described which improves error performance of synchronous data links without sacrificing data rate or requiring more bandwidth by channel coding with expanded sets of multilevel/phase signals in a manner which increases free Euclidean distance.Abstract:
A coding technique is described which improves error performance of synchronous data links without sacrificing data rate or requiring more bandwidth. This is achieved by channel coding with expanded sets of multilevel/phase signals in a manner which increases free Euclidean distance. Soft maximum--likelihood (ML) decoding using the Viterbi algorithm is assumed. Following a discussion of channel capacity, simple hand-designed trellis codes are presented for 8 phase-shift keying (PSK) and 16 quadrature amplitude-shift keying (QASK) modulation. These simple codes achieve coding gains in the order of 3-4 dB. It is then shown that the codes can be interpreted as binary convolutional codes with a mapping of coded bits into channel signals, which we call "mapping by set partitioning." Based on a new distance measure between binary code sequences which efficiently lower-bounds the Euclidean distance between the corresponding channel signal sequences, a search procedure for more powerful codes is developed. Codes with coding gains up to 6 dB are obtained for a variety of multilevel/phase modulation schemes. Simulation results are presented and an example of carrier-phase tracking is discussed.read more
Citations
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Wireless broadband single-carrier systems with MMSE turbo equalization receivers
TL;DR: This thesis focuses on turbo equalization with prior information using the principle of interference cancellation followed by minimum mean squared error (MMSE) filtering to exhibit both superior convergence and low computational complexity among the compared equalizers.
Journal ArticleDOI
Hybrid iterative multiuser detection for channel coded space division multiple access OFDM systems
TL;DR: A GA- aided MMSE MUD is proposed for employment in a TTCM-assisted SDMA-OFDM system, which is capable of achieving a similar performance to that attained by its optimum MLD-aided counterpart at a significantly lower complexity, especially at high user loads.
Patent
Memory Quality Monitor Based Compensation Method and Apparatus
Liikanen Bruce A,Cadloni Gerald L,Koudele Larry J,John L. Seabury,Stephen P. Van Aken,Guy R. Wagner +5 more
TL;DR: In this paper, an encoder reads a set of data from memory cells to obtain retrieved data influenced by one or more distortion mechanisms as a result of having been stored, and a quality metric is generated responsive to the retrieved data that changes in value responsive to differences between the user data and associated retrieved data.
Proceedings ArticleDOI
On enhancing hierarchical modulation
TL;DR: An enhanced hierarchical modulation technique along with three optimization schemes, in which the enhancement-layer signal constellation is rotated, are presented and analyzed and can help recover the performance loss of regular hierarchical modulation due to inter-layer interference with little complexity increase.
Journal ArticleDOI
Multifrequency trellis coding with low delay for fading channels
TL;DR: An L-frequency trellis coding scheme designed for fading channels that provides diversity up to order L is described and a numerical approximation to this upper-bound and the design of a two-state and two four-state, two-frequency codes are presented.
References
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Information Theory and Reliable Communication
TL;DR: This chapter discusses Coding for Discrete Sources, Techniques for Coding and Decoding, and Source Coding with a Fidelity Criterion.
Journal ArticleDOI
The viterbi algorithm
TL;DR: This paper gives a tutorial exposition of the Viterbi algorithm and of how it is implemented and analyzed, and increasing use of the algorithm in a widening variety of areas is foreseen.
Book
Principles of Communication Engineering
I. M. Jacobs,J. M. Wozencraft +1 more
TL;DR: Textbook on communication engineering emphasizing random processes, information and detection theory, statistical communication theory, applications, etc.
Journal ArticleDOI
Convolutional codes I: Algebraic structure
TL;DR: Minimal encoders are shown to be immune to catastrophic error propagation and, in fact, to lead in a certain sense to the shortest decoded error sequences possible per error event.
Journal ArticleDOI
Coherent and Noncoherent Detection CPFSK
W. Osborne,M. Luntz +1 more
TL;DR: This work provides a complete analysis of the performance of CPFSK at high SNR as well as low SNR and thereby unifies and extends the results previously available.