Direct Space-Time GF(q) LDPC Modulation
ABSTRACT Wireless communication using multiple-input multiple-output (MIMO) systems improves throughput and enhances reliability for a given total transmit power. In this paper, potential performance gains are investigated via a direct Galois field [GF(q)] low-density parity-check (LDPC) space-time coding and modulation scheme. The field order q is chosen such that the number of bits per GF(q) LDPC symbol matches the number of bits per space-time symbol. The result is an elegant coding and decoding scheme that leverages the powerful LDPC iterative decoding technique. Results for 2, 3, and 4 transmitter systems with relatively short block lengths of around 2000 bits are provided, demonstrating frame-error- rate performances as close as 0.5 dB to the probability of outage upper bound.
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ABSTRACT: Wireless communication using multiple-input multiple-output (MIMO) systems improves throughput and enhances reliability for a given total transmit power. Achieving a higher data rate in MIMO systems requires utilizing an effective space-time coding and modulation scheme. The appropriate algorithm to use for a system will depend on parameters such as the number of transmit/receive antennas, target spectral efficiency, complexity limitations, channel environment, and other factors. In this paper, we examine the performance of various two-transmit and four-transmit space-time coding schemes under different channel types and target data rates. We compare the performance of state of the art space-time coding schemes including direct non-binary LDPC GF(q) modulation, bit interleaved coded modulation using iterative detection, and space-time trellis coded modulation. We obtain a tradeoff between performance and complexity of these various schemes.Signals, Systems and Computers, 2009 Conference Record of the Forty-Third Asilomar Conference on; 12/2009
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ABSTRACT: Multiple-input multiple-output (MIMO) wireless communication systems enhance reliability and improve throughput for a given total transmit power. In actual systems, the channel and noise parameters must be estimated to capture the MIMO gains. In this paper, we couple a direct, q-ary Galois field [GF(q)], low-density parity-check (LDPC) space-time coding and modulation scheme with a receiver that iterates between decoding the transmitted symbols, estimating the convolutive MIMO channel with pilots and symbol decisions, and removing inter-symbol interference. The result is a powerful system that outperforms linear space-time equalization and performs within one decibel of a system with perfect channel knowledge and no inter-symbol interference.Signals, Systems and Computers, 2008 42nd Asilomar Conference on; 01/2008