Near-Capacity Turbo Trellis Coded Modulation Design

IEEE Transactions on Communications, 2000

Bandwidth efficient parallel-concatenated Turbo Trellis Coded Modulation (TTCM) schemes were designed for communicating over uncorrelated Rayleigh fading channels. A symbol-based union bound was derived for analysing the error floor of the proposed TTCM schemes. A pair of In-phase (I) and Quadrature-phase (Q) interleavers were employed for interleaving the I and Q components of the TTCM coded symbols, in order to attain an increased diversity gain. The decoding convergence of the IQ-TTCM schemes was analysed using symbol-based EXtrinsic Information Transfer (EXIT) charts. The best TTCM component codes were selected with the aid of both the symbolbased union bound and non-binary EXIT charts, for designing capacity-approaching IQ-TTCM schemes in the context of 8PSK, 16QAM, 32QAM and 64QAM modulation schemes. Index Terms-Decoding convergence, distance spectrum, code design, EXIT charts, Turbo Trellis Coded Modulation, union bound. Jörg Kliewer (S'97-M'99-SM'04) received the Dipl.-Ing. (M.Sc.) degree in Electrical Engineering from Hamburg

IEEE Vehicular Technology Conference, 2006

In this paper we design bandwidth efficient parallel-concatenated Turbo Trellis Coded Modulation (TTCM) schemes for communicating over AWGN and uncorrelated Rayleigh fading channels. The convergence properties of the symbolbased TTCM schemes employing various constituent codes, were analysed using symbol-based EXtrinsic Information Transfer (EXIT) charts. The traditional method used of generating EXIT charts is based on computationally complex multidimensional histogram measurements, which is only feasible for analysing TTCM schemes employing loworder modulation schemes, such as 4PSK and 8PSK. Hence, a novel low-complexity technique was employed in this paper for computing the symbol-based EXIT charts. Capacity-approaching TTCM schemes were designed based on the best constituent codes found when employing 8PSK, 16QAM, 32QAM and 64QAM modulation schemes.

AEU - International Journal of Electronics and Communications, 2013

In this paper, the design of newly introduced turbo encoding scheme called 'Unpunctured Turbo Trellis-Coded Modulation' (UTTCM) is exposed. The performance improvement of this encoding scheme is obtained by setting a design criterion for each of its components namely: the search rules of best constituent encoders' generator polynomials, the constellation and the associated mapping. Simulation results show that the optimized UTTCM outperforms TTCM and PCTCM for all considered spectral efficiencies, and presents competitive error floors. As examples, for a spectral efficiency of 3 bits/symbol (bps), UTTCM with 8 decoding iterations outperforms TTCM by 0.05 dB at BER = 10 −4 ; and for a spectral efficiency of 4 bps and 6 decoding iterations, UTTCM outperforms Fragouli's PCTCM by 0.07 dB at BER = 10 −5 .

Wireless Personal …, 2005

This paper investigates the performance of a new Turbo Trellis Coded Modulation scheme over correlated flat fading channels with channel interleaving. The novelty of the scheme is based on the application of a new modified transition metric incorporated in the symbol-by-symbol MAP algorithm. We consider frequency nonselective, slow Rayleigh fading channels. Extensive simulation results together with EXIT chart analysis show that the proposed scheme achieves better performance compared to the conventional transition metric when channel state information is not available at the decoder.

VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008

In this contribution we design the Iteratively Decoded Self-Concatenated Convolutional Codes (SECCC-ID) using Extrinsic Information Transfer (EXIT) charts. Good constituent Trellis Coded Modulation (TCM) codes are selected for communicating over both uncorrelated Rayleigh fading and Additive White Gaussian Noise (AWGN) channels. At the receiver iterative decoding is invoked for exchanging extrinsic information between the hypothetical decoder components. The convergence behaviour of the decoder is analysed with the aid of symbol-based EXIT charts. Similarly, the search for the best TCM constituent codes is also based on EXIT chart analysis. Finally, we demonstrate that the selected codes are capable of operating within 1 dB from the maximum achievable rate.

FOREX Publication , 2023

In the context of data communication, encountering fading channels can lead to errors occurring at the receiving end due to multipath propagation. To address this challenge, researchers have persistently worked towards developing Error Correction Schemes that effectively manage these errors and guarantee error-free data reception for the receiver. One area of focus lies in the implementation of Forward Error Correction Schemes directly at the transmitter end. Nonetheless, integrating error correction coding using these schemes comes with the drawback of increased bandwidth requirements since additional bits must be included to facilitate error correction. Fortunately, there exists a coding scheme known as Trellis Coded Modulation (TCM), which specifically tackles this concern. In the case of TCM, the modulation scheme has been chosen based on the rate of the convolutional coding scheme. Nevertheless, TCM has certain limitations when it comes to correcting a high number of errors, which prompted the emergence of Turbo Coding. Turbo Coding employs two coders at the transmitter, arranged either in a serial or parallel configuration, along with an appropriate decoder at the receiver. This paper introduces a Turbo Coding scheme design utilizing convolutional coders with a rate of 2/3, arranged in a serially concatenated configuration, resulting in an effective rate of 4/9. For preserving bandwidth, the Turbo Coding is applied to TCM scheme. Consequently, when employing the convolutional coding scheme with a rate of 2/3, the modulation scheme has to be 8-QAM. However, to maintain bandwidth after coding, when utilizing the Turbo coding scheme with a rate of 4/9, the modulation scheme is upgraded to 512-QAM. MATLAB simulations were conducted to evaluate the error correcting capabilities of the designed scheme compared to the convolutional coding scheme that uses the constituent convolutional encoder. The comparison has also been made with the uncoded data communication utilizing simple QPSK modulation scheme. The results indicate that under Rician fading channel conditions, the Turbo Trellis Coding Modulation Scheme provides an approximate gain of 5 dB compared to the convolutional coding scheme and approximately 8 dB gain compared to uncoded one.

IEEE International …, 1996

Journal of Electronics (China), 2002

The paper presents a kind of reasonable structure for implementing MQAM T-TCM based on the principles of turbo codes and TCM for the first time. It can also be expanded to PSK T-TCM system, and the corresponding decoding algorithm is derived. By computer simulation, its performance is analyzed. The results show that T-TCM takes the advantages of turbo codes and TCM technology, and is a kind of bandwidth-efficient coded-modulation technique obtaining high coding gain. So, in the future, T-TCM would be applied in many fields.

2009 IEEE International Conference on Communications

In this contribution, we propose a Distributed Turbo Trellis Coded Modulation (DTTCM) scheme for cooperative communications. The DTTCM scheme is designed based on its decoding convergence with the aid of non-binary Extrinsic Information Transfer (EXIT) charts. The source node transmits TTCM symbols to both the relay and the destination nodes during the first transmission period. The relay performs TTCM decoding and re-encodes the information bits using a Recursive Systematic Convolutional (RSC) code regardless whether the relay can decode correctly or not. Only the parity bits are transmitted from the relay node to the destination node during the second transmission period. The resultant symbols transmitted from the source and relay nodes can be viewed as the coded symbols of a three-component parallel-concatenated TTCM scheme. At the destination node, a novel three-component TTCM decoding is performed. It is shown that the performance of the DTTCM matches exactly the EXIT chart analysis. It also performs very closely to its idealised counterpart that assumes perfect decoding at the relay.

2013

— In this contribution we design the Iteratively Decoded