Trellis-coded unitary space-time modulation

EURASIP Journal on Advances in Signal Processing, 2002

A design method for recursive space-time trellis codes and parallel-concatenated space-time turbo coded modulation is proposed that can be applied to an arbitrary existing space-time trellis code. The method enables a large, systematic increase in coding gain while preserving the maximum transmit diversity gain and bandwidth efficiency property of the considered spacetime trellis code. Applying the above method to Tarokh et al. space-time trellis codes, significant performance improvements can be obtained even with extremely short input information frames. The application of space-time turbo coded modulation to the space-frequency domain is also proposed in this paper. Exploiting the bandwidth efficient orthogonal frequency division modulation (OFDM), multiple transmit antennas and large frequency selectivity offered by typical low mobility indoor environments, the proposed space-frequency turbo coded modulation performs within 2.5 dB of the outage capacity for a variety of practical wideband multiple-input multiple-output (MIMO) radio channels. the University of Oulu. Currently Prof. Latva-aho is Director of Centre for Wireless Communications at the University of Oulu. His research interests include future broadband wireless communication systems and related transceiver algorithms. Prof. Latva-aho has published more than 50 conference or journal papers in the field of CDMA communications.

Wireless Personal Communications, 2013

The space time trellis code (STTC) is a combined design of error-control coding, modulation and transmit-receive diversity that improves data rate and error performance in a wireless channel without any loss in spectral efficiency. It can either be described by a graphical representation, or, in terms of closed analytical forms that lead to a more tractable generator matrix description. However, the main difficulty in generating best code is the long search duration which makes both trellis implementation and generator matrix description difficult, thereby, limiting the use of STTC in wireless links. Since an exhaustive search over all the matrix entries turns out to be impractical if the number of transmitter, encoder states and/or constellation size is very high, some literature provide techniques to reduce the search complexity. Some of them are sub-optimal, some are good. However, none reports any straightforward rule of thumb to design the generator matrix. In this paper, we propose two very simple rules to construct the generator matrix for designing STTC with any arbitrary number of transmit antennas and any memory-less constellation. Mathematical justification behind the rules has been presented. It has been shown that the simplicity of proposed rules reduces the code search complexity to a large extent along with a similar or better coding gain compared to those presented in previous literature. In addition, the STTCs obtained from proposed rules perform no worse than the codes given in previous literature in terms of error rate.

2008 Fourth International Conference on Wireless Communication and Sensor Networks, 2008

In this paper, we analyze the performance of space-time codes. In particular, we derive an upper bound of the frame error probabilities for space-time trellis coded modulations over quasi-static Rayleigh fading channels. Two techniques, modified bounding and limiting before averaging, are used to derive the new bound. The newly derived upper bound is very accurate, needs only the distance spectrum of the space-time code, and can be computed through single numerical integration. Numerical results show that the new upper bound is much tighter than other existing bounds, especially in the case of one receive antenna.

IEEE Globecom 2006, 2006

We consider a multi-antenna system using spacetime trellis codes (STTC) over independent, non-identically distributed, rapid, Rayleigh fading channels with pilot-symbolassisted-modulation channel estimation. The maximum likelihood (ML) receiver structure that incorporates the imperfect channel state information (CSI) from the pilot channel measurements, is derived. The exact pairwise error probability (PEP) and PEP bounds for the ML receiver are obtained. Using the explicit PEP bounds obtained, a new pilot power allocation scheme is proposed to improve the performance of STTC at no additional cost of bandwidth or power.

2003

In wireless mobile communication systems, antenna diversity is one of the most important techniques to improve the performance. Codes suitable for antenna diversity which achieve full diversity, full rate and good coding gains are preferred when there is a small number of parallel channels. A concatenated space-time block code and multiple trellis coded modulation (STBC-MTCM) scheme achieves this goal. An 8-state STBC-MTCM with two antennas at the transmitter and one antenna at the receiver is implemented with interleaver and channel estimation on the OSU/UCLA wireless narrowband testbed. The design is described in detail. The system hardware setup is briefly overviewed and simulation bench test results are also provided. During our bench tests, an error floor was observed at high SNR's. This study is a first attempt to quantify the limits of achievable performance of real implementations of space-time coding.

European Transactions on Telecommunications, 2007

In this paper, we focus on the design of super-orthogonal space-time (ST) trellis codes with a 32-point quadrature amplitude modulation (QAM) signal constellation, allowing wireless communication with a data rate of 5 bits per signalling interval. Considering a mobile wireless communications system with two transmit antennas, we form a four-dimensional (4D) signal constellation as a Cartesian product of two 2D rectangular signal sets. The first antenna transmits a 4D point as two concatenated 2D points in two consecutive baud intervals. The 2D symbols transmitted by the second antenna are not independent, but so chosen as to form, together with the symbols transmitted by the first antenna, the entries of a 2 Â 2 orthogonal matrix. For a rectangular constellation, as much as four sets of 2 Â 2 orthogonal matrices can be built. To obtain a higher data rate, the union of two of them is used to construct a super-orthogonal signal set. With 2 Â 2 orthogonal matrices, we then label the state transitions of a trellis diagram describing the operation of the encoder. For the performance analysis, two different channel models are employed. The first channel model is based on the assumption that the paths between different pairs of transmit-receive antennas are uncorrelated, while the second model takes into account the effect of spatial antenna correlation at both the base station (BS) and at the mobile station (MS). The analysis of the frame-error rate (FER) and the bit-error rate (BER) demonstrates the excellent performance of the proposed high data rate super-orthogonal ST trellis code.

IEE Proceedings - Communications, 2004

The authors address the problematic issues in generating space-time trellis codes, and propose novel methods for reducing the exponentially growing full code search. It is proved that by exploiting the symmetry in QAM and PSK constellations, together with the modulo operation in the encoder, the number of possible combinations in the generator matrix can be halved when performing a full search to obtain optimal codes. It is also shown that for a fixed set of columns in the generator matrix, interchanging columns yields identical results, hence reducing the full code search by the factorial of the number of transmit antennas. Furthermore, the existing sub-optimal (but fast) method for obtaining codes is investigated and results from this method are compared with those obtained from the two proposed methods. Using the suggested methods, novel spacetime codes for both slow and fast fading environments are generated and their performance is evaluated through frame error probabilities obtained by simulation.

IEEE Transactions on Communications, 1999

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 n streams that are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n 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.

IEEE Signal Processing Letters, 2002

In this letter, we consider a space-time differential modulation scheme where neither the transmitter nor the receiver has to know the channel. Our scheme is based on the theory of unitary space-time block codes. Compared to the existing differential modulation schemes for multiple antennas our scheme has a much smaller computational complexity. Moreover, our codes have a higher coding gain and lower bit error rate than the codes recently proposed by other researchers.

IEEE Transactions on Wireless Communications, 2011

Spatial modulation (SM), in which multiple antennas are used to convey information besides the conventional M-ary signal constellations, is a new multiple-input multiple-output (MIMO) transmission technique, which has recently been proposed as an alternative to V-BLAST. In this paper, a novel MIMO transmission scheme, called spatial modulation with trellis coding (SM-TC), is proposed. Similar to the conventional trellis coded modulation (TCM), in this scheme, a trellis encoder and an SM mapper are jointly designed to take advantage of the benefits of both. A soft decision Viterbi decoder, which is fed with the soft information supplied by the optimal SM decoder, is used at the receiver. The pairwise error probability (PEP) upper bound is derived for the SM-TC scheme in uncorrelated quasi-static Rayleigh fading channels. From the PEP upper bound, code design criteria are given and then used to obtain new 4-, 8and 16-state SM-TC schemes using QPSK and 8-PSK modulations for 2, 3 and 4 bits/s/Hz spectral efficiencies. It is shown via computer simulations and also supported by a theoretical error performance analysis that the proposed SM-TC schemes achieve significantly better error performance than the classical space-time trellis codes and coded V-BLAST systems at the same spectral efficiency, yet with reduced decoding complexity.