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

Several aspects of the design and optimization of coded multiple-antenna transmission diversity methods for slowly time-varying channels are explored from an information-theoretic perspective. Both optimized vector-coded systems, which can achieve the maximum possible performance, and suboptimal scalar-coded systems, which reduce complexity by exploiting suitably designed linear precoding, are investigated. The achievable rates and associated outage characteristics of these spatial diversity schemes are evaluated and compared, both for the case when temporal diversity is being jointly exploited and for the case when it is not. Complexity and implementation issues more generally are also discussed.

Space-time convolutional codes, that provide maximum diversity and coding gain, are produced for cases with PSK modulation and various numbers of states and antennas. The codes are found

Space-time convolutional codes have shown considerable promise for providing improved performance for wireless communication through combined diversity and coding gain. However, systematic design procedures for space-time convolutional codes have not yet been developed. To date, the few existing example space-time codes have been developed using hand design. Systematic design procedures are presented here, which are based on a few theorems addressing necessary and sufficient conditions on spacetime codes which achieve maximum diversity gain. Other theorems provide methods for calculating and bounding coding gain. A new simple, but highly useful, measure of coding gain is also suggested which can augment existing measures. The use of a possible design procedure is illustrated and new codes are provided which outperform all existing space-time convolutional codes of similar complexity. Keywords space-time coding, space-time modulation, transmit diversity, convolutional coding. This pa...

Abstract—Wireless communication using multiple-input multiple-output (MIMO) systems enables increased spectral efficiency for a given total transmit power. Increased capacity is achieved by introducing additional spatial channels that are exploited using space–time coding. In this paper, the environmental factors that affect MIMO capacity are surveyed. These factors include channel complexity, external interference, and channel estimation error. The maximum spectral efficiency of MIMO systems in which both transmitter and receiver know the channel (using channel estimate feedback) is compared with MIMO systems in which only the receiver knows the channel. Channel complexity is studied using both simple stochastic physical scattering and asymptotic large random matrix models. Both uncooperative (worst-case) and cooperative (amenable to multiuser detection) interference are considered. An analysis for capacity loss associated with channel estimation error at the transmitter is introduced. Index Terms—Channel capacity, channel phenomenology, information theory, interference cancellation, MIMO communication, multiuser detection, space–time coding. I.

Abstract—Wireless communication using multiple-input multiple-output (MIMO) systems enables increased spectral efficiency and link reliability for a given total transmit power. Increased capacity is achieved by introducing additional spatial channels which are exploited using space-time coding. The spatial diversity improves the link reliability by reducing the adverse effects of link fading and shadowing. The choice of coding and the resulting performance improvement are dependent upon the channel phenomenology. In this paper, experimental channel-probing estimates are reported for outdoor environments near the personal communication services frequency allocation (1790 MHz). A simple channel parameterization is introduced. Channel distance metrics are introduced. Because the bandwidth of the channel-probing signal (1.3 MHz) is sufficient to resolve some delays in outdoor environments, frequency-selective fading is also investigated. Channel complexity and channel stationarity are investigated. Complexity is associated with channel-matrix singular value distributions. Stationarity is associated with the stability of channel singular value and singular vector structure over time. Index Terms—Channel coding, information theory, multipath channels, multiple-input multiple-output (MIMO) systems.

Space-Time block codes (STBCs) based on Orthogonal Designs (ODs) is well known due to its simple (single-symbol) ML decoding. A fulldiversity, symbol rate one, square complex OD exists only for 2 antennas which is basically the Alamouti scheme. For larger number of antennas either the symbol-rate or full-diversity or the advantage of single-symbol decoding needs to be sacri ced in general. In this paper we introduce a STBC for four transmit antennas based on a non-orthogonal square design, which we call Coordinate-Interleaved Design (CID), that achieves full-diversity (four), symbol-rate one as well as single-symbol ML decoding. This scheme can be combined with any number M of receive antennas to achieve a diversity of 4M .

Abstract — The capacity of multiple input, multiple output (MIMO) wireless channels is computed for Ricean channels. The novelty is a geometrical (ray-tracing) interpretation of the MIMO channel capacity formula to find array geometries which greatly enhance channel capacity compared to single input–single output (SISO) systems. Index Terms—Array signal processing, channel capacity, land mobile radio cellular systems. I.

In this paper, the application of three blind (or selfreference) spatial diversity signal processing methods to Spread Spectrum (SS) communications is described. These methods do not require any kind of side information beyond knowledge of the signal structure, in contraposition to methods that depend on training sequences.

The matched filter bound for space-time block coded multiple-input multiple-output systems in a frequency-selective Nakagami fading channel is derived for binary phase shift keying. Arbitrary correlation among the elements of the transmitter and the receiver antenna arrays is taken into account. Moreover, in the special case of Rayleigh fading the effect of the pulse shape is also considered. The resulting expressions allow for evaluation of the impacts of different system design parameters and the characteristics of the propagation environment on the bit-error rate performance of the system.