4,526 research outputs found
Space-Time Signal Design for Multilevel Polar Coding in Slow Fading Broadcast Channels
Slow fading broadcast channels can model a wide range of applications in
wireless networks. Due to delay requirements and the unavailability of the
channel state information at the transmitter (CSIT), these channels for many
applications are non-ergodic. The appropriate measure for designing signals in
non-ergodic channels is the outage probability. In this paper, we provide a
method to optimize STBCs based on the outage probability at moderate SNRs.
Multilevel polar coded-modulation is a new class of coded-modulation techniques
that benefits from low complexity decoders and simple rate matching. In this
paper, we derive the outage optimality condition for multistage decoding and
propose a rule for determining component code rates. We also derive an upper
bound on the outage probability of STBCs for designing the
set-partitioning-based labelling. Finally, due to the optimality of the
outage-minimized STBCs for long codes, we introduce a novel method for the
joint optimization of short-to-moderate length polar codes and STBCs
Golden Space-Time Trellis Coded Modulation
In this paper, we present a concatenated coding scheme for a high rate
multiple-input multiple-output (MIMO) system over slow fading
channels. The inner code is the Golden code \cite{Golden05} and the outer code
is a trellis code. Set partitioning of the Golden code is designed specifically
to increase the minimum determinant. The branches of the outer trellis code are
labeled with these partitions. Viterbi algorithm is applied for trellis
decoding. In order to compute the branch metrics a lattice sphere decoder is
used. The general framework for code optimization is given. The performance of
the proposed concatenated scheme is evaluated by simulation. It is shown that
the proposed scheme achieves significant performance gains over uncoded Golden
code.Comment: 33 pages, 13 figure
Cyclic division algebras: a tool for space-time coding
Multiple antennas at both the transmitter and receiver ends of a wireless digital transmission channel may increase both data rate and reliability. Reliable high rate transmission over such channels can only be achieved through Space–Time coding. Rank and determinant code design criteria have been proposed to enhance diversity and coding gain. The special case of full-diversity criterion requires that the difference of any two distinct codewords has full rank.
Extensive work has been done on Space–Time coding, aiming at
finding fully diverse codes with high rate. Division algebras have been proposed as a new tool for constructing Space–Time codes, since they are non-commutative algebras that naturally yield linear fully diverse codes. Their algebraic properties can thus be further exploited to
improve the design of good codes.
The aim of this work is to provide a tutorial introduction to the algebraic tools involved in the design of codes based on cyclic division algebras. The different design criteria involved will be illustrated, including the constellation shaping, the information lossless property, the non-vanishing determinant property, and the diversity multiplexing trade-off. The final target is to give the complete mathematical background underlying the construction of the Golden code and the other Perfect Space–Time block codes
Golden Coded Multiple Beamforming
The Golden Code is a full-rate full-diversity space-time code, which achieves
maximum coding gain for Multiple-Input Multiple-Output (MIMO) systems with two
transmit and two receive antennas. Since four information symbols taken from an
M-QAM constellation are selected to construct one Golden Code codeword, a
maximum likelihood decoder using sphere decoding has the worst-case complexity
of O(M^4), when the Channel State Information (CSI) is available at the
receiver. Previously, this worst-case complexity was reduced to O(M^(2.5))
without performance degradation. When the CSI is known by the transmitter as
well as the receiver, beamforming techniques that employ singular value
decomposition are commonly used in MIMO systems. In the absence of channel
coding, when a single symbol is transmitted, these systems achieve the full
diversity order provided by the channel. Whereas this property is lost when
multiple symbols are simultaneously transmitted. However, uncoded multiple
beamforming can achieve the full diversity order by adding a properly designed
constellation precoder. For 2 \times 2 Fully Precoded Multiple Beamforming
(FPMB), the general worst-case decoding complexity is O(M). In this paper,
Golden Coded Multiple Beamforming (GCMB) is proposed, which transmits the
Golden Code through 2 \times 2 multiple beamforming. GCMB achieves the full
diversity order and its performance is similar to general MIMO systems using
the Golden Code and FPMB, whereas the worst-case decoding complexity of
O(sqrt(M)) is much lower. The extension of GCMB to larger dimensions is also
discussed.Comment: accepted to conferenc
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