Abstract
Space-time block codes alone generally have little or no coding gain. To extract coding gain, space-time block codes have been previously concatenated with an outer trellis to generate simple and powerful codes, recognized as superorthogonal codes. That work has two main themes: it explores methods and algorithms that generate coding gain in block codes exclusive of a trellis, as glowing as improve the coding gain in the presence of a trellis. At what time an external trellis is obtainable, our results simplify the super-orthogonal codes by finding new code supersets and corresponding set partitioning, resulting in improved coding gain. New algorithms are developed to efficiently build trellises for various full-rate MIMO codes, for that reason they extend the concept of trellis-block MIMO coding beyond orthogonal and quasi-orthogonal codes. In the absence of a trellis, a technique called single-block coded modulation is proposed to improve the coding gain of all varieties of space-time block codes. In that thesis they discuss coded modulation schemes designed for multiple antenna wireless channels without information of the channel at the transmitter. Space-time coding reduces the detrimental effect of channel fading. The space-time receiver takes advantage of diverse propagation paths between transmits and receive antennas to improve the performance of wireless communication. It contains a literature survey of the recent developments in MIMO signaling. The main types of spacetime codes are block and trellis codes. Space-time block codes (STBC) operate on a block of input symbols, producing a matrix output. Space-time block codes do not generally provide coding gain. Their main feature is the provision of diversity with a very simple decoding scheme. Concatenation of orthogonal space-time block codes (OSTBC) with an outer trellis has led to simple and powerful codes, known as super-orthogonal codes or STB-TCM.
Highlights
orthogonal space-time block codes (OSTBC) have full diversity, but have little or no coding gain
OSTBC have full diversity, but have little or no coding gain. To provide both diversity and coding gain that can specify a spacetime code that has an in-built channel coding mechanism example space-time trellis codes, or one can choose a space-time block code concatenated with an outer channel code
Chambers et al [4] investigated on a modified quasi-orthogonal space-time block coding (M QO-Space-time block codes (STBC)) scheme with full diversity and code gain distance (CGD) for use in asynchronous relay networks
Summary
OSTBC have full diversity (nT * nR ) , but have little or no coding gain. To provide both diversity and coding gain that can specify a spacetime code that has an in-built channel coding mechanism example space-time trellis codes, or one can choose a space-time block code concatenated with an outer channel code. R2 = h1c2* + h2c1* + n1 where r1 and r2 are the received signals over two consecutive symbol periods and n1 and n2 represent the receiver noise and are modeled as complex Gaussian random variables with zero mean and potheyr spectral density No=2 per dimension. They define the received signal vector = [r1r2*]T, the code symbol vector c = [c1c2 ]T , and the noise vector n = [n1n2*]T. Earlier they saw that orthogonal codes allow a linear receiver, but in general they support a rate smaller than one symbol per transmission for Lt>2. Let us consider the following spacetime block code for four transmit antennas as c1 −c2* −c3*
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