Abstract-Block transmission with cyclic prefix is a promising technique to realize high-speed data rates in frequency-selective fading channels. Many popular linear precoding schemes, including orthogonal frequency-division multiplexing (OFDM), singlecarrier (SC) block transmission, and time-reversal (TR), can be interpreted as such a block transmission. This paper presents a unified performance analysis that shows how the optimal precoding strategy depends on the optimization criterion such as capacity, mean-square error, and secrecy. We analyze three variants of TR methods (based on maximum-ratio combining, equal-gain combining and selective combining) and two-types of pre-equalization methods (zero-forcing and minimum meansquare error). As one application of our framework, we derive optimal precoding (i.e., OFDM with optimal power and phase control) in the presence of interference limitation for distributed antenna systems; we find that without power/phase control, OFDM does not have any capacity advantage over SC transmissions. When comparing SC and TR, we verify that for singleantenna systems in the high SNR regimes, SC has a capacity advantage; however, TR performs better in the low SNR regime. For distributed multiple-antenna systems, TR always provides higher capacity, and the capacity of TR can approach that of optimal precoders with a large number of distributed antennas. Furthermore, we make an analysis of secrecy capacity which shows how high-rate messages can be transmitted towards an intended user without being decoded by the other users from the viewpoint of information-theoretic security. We demonstrate that TR precoding can be the best candidate among the nonoptimal precoders for achieving high secrecy capacity, while the optimal precoder offers a significant gain over those non-optimal precoders. Index Terms-Distributed antenna systems, cooperative diversity, linear block precoding, frequency-selective fading, information-theoretic security.
In REF , assuming the linear Time-Reversal (TR) transmissions from distributed antenna systems, the asymptotic secrecy rate is obtained in the large and low SNR regimes, respectively.
Capacity, MSE and Secrecy Analysis of Linear Block Precoding for Distributed Antenna Systems in Multi-User Frequency-Selective Fading Channels
IEEE Transactions on Communications
IEEE Transactions on Communications
Computer Science