Embedded Rank Distance Codes for ISI channels

Designs for transmit alphabet constrained space-time codes naturally lead to questions about the design of rank distance codes. Recently, diversity embedded multi-level space-time codes for flat fading channels have been designed from sets of binary matrices with rank distance guarantees over the binary field by mapping them onto QAM and PSK constellations. In this paper we demonstrate that diversity embedded space-time codes for fading Inter-Symbol Interference (ISI) channels can be designed with provable rank distance guarantees. As a corollary we obtain an asymptotic characterization of the fixed transmit alphabet rate-diversity trade-off for multiple antenna fading ISI channels. The key idea is to construct and analyze properties of binary matrices with a particular structure induced by ISI channels.Comment: Submitted to IEEE Transactions on Information Theor

Combined Source and Channel Strategies for Optimized Video Communications

ISBN 978-953-7619-70-

Differential Diversity-Embedding Space-Time Block Coding for 2 and 4 Transmit Antennas

Abstract-Diversity-Embedding Space-Time Block Coding (DE-STBC), introduced in [1], enables Unequal Error Protection (UEP) using multiple transmit antennas. Even though these codes do not require channel state information (CSI) at the transmitter, they do need it at the receiver for decoding. A novel differential DE-STBC scheme is proposed in this paper to eliminate the need for channel estimation at the receiver which is especially costly with multiple transmit and receive antennas. Most previously proposed differential schemes in the literature are based on orthogonal STBC and hence are not applicable to the nonorthogonal family of DE-STBC considered in this paper

Diversity Embedded Space-Time Codes

Rate and diversity impose a fundamental trade-off in wireless communication. High-rate space-time codes come at a cost of lower reliability (diversity), and high reliability (diversity) implies a lower rate. However, wireless networks need to support applications with very different Quality-of-Service (QoS) requirements, and it is natural to ask what characteristics should be built into the physical layer link in order to accomodate them. In this paper we de- sign high-rate space-time codes that have a high-diversity code embedded within them. This allows a form of communication where the high-rate code opportunistically takes advantage of good channel realizations while the embedded high-diversity code provides guarantees that at least part of the information is received reliably. We provide constructions of linear and non-linear codes for a fixed transmit alphabet constraint. The non-linear constructions are a natural generalization to wireless channels of multilevel codes developed for the AWGN chan- nel that are matched to binary partitions of QAM and PSK constellations. The importance of set-partitioning to code design for the wireless channel is that it provides a mechanism for translating constraints in the binary domain into lower bounds on diversity protection in the complex domain. We investigate the systems implications of embedded diversity codes by examining value to unequal error protection, rate opportunism and packet delay optimiza- tion. These applications demonstrate that diversity-embedded codes have the potential to outperform traditional single-layer codes in moderate SNR regimes