92 research outputs found
Full Diversity Space-Time Block Codes with Low-Complexity Partial Interference Cancellation Group Decoding
Partial interference cancellation (PIC) group decoding proposed by Guo and
Xia is an attractive low-complexity alternative to the optimal processing for
multiple-input multiple-output (MIMO) wireless communications. It can well deal
with the tradeoff among rate, diversity and complexity of space-time block
codes (STBC). In this paper, a systematic design of full-diversity STBC with
low-complexity PIC group decoding is proposed. The proposed code design is
featured as a group-orthogonal STBC by replacing every element of an Alamouti
code matrix with an elementary matrix composed of multiple diagonal layers of
coded symbols. With the PIC group decoding and a particular grouping scheme,
the proposed STBC can achieve full diversity, a rate of and a
low-complexity decoding for transmit antennas. Simulation results show that
the proposed codes can achieve the full diversity with PIC group decoding while
requiring half decoding complexity of the existing codes.Comment: 10 pages, 3 figures
Signal detection for orthogonal space-time block coding over time-selective fading channels: A PIC approach for the G(i) systems
One major assumption in all orthogonal space-time block coding (O-STBC) schemes is that the channel remains static over the entire length of the codeword. However, time selective fading channels do exist, and in such case the conventional O-STBC detectors can suffer from a large error floor in the high signal-to-noise ratio (SNR) cases. This paper addresses such an issue by introducing a parallel interference cancellation (PIC) based detector for the G(i) coded systems (i = 3 and 4)
An Adaptive Conditional Zero-Forcing Decoder with Full-diversity, Least Complexity and Essentially-ML Performance for STBCs
A low complexity, essentially-ML decoding technique for the Golden code and
the 3 antenna Perfect code was introduced by Sirianunpiboon, Howard and
Calderbank. Though no theoretical analysis of the decoder was given, the
simulations showed that this decoding technique has almost maximum-likelihood
(ML) performance. Inspired by this technique, in this paper we introduce two
new low complexity decoders for Space-Time Block Codes (STBCs) - the Adaptive
Conditional Zero-Forcing (ACZF) decoder and the ACZF decoder with successive
interference cancellation (ACZF-SIC), which include as a special case the
decoding technique of Sirianunpiboon et al. We show that both ACZF and ACZF-SIC
decoders are capable of achieving full-diversity, and we give sufficient
conditions for an STBC to give full-diversity with these decoders. We then show
that the Golden code, the 3 and 4 antenna Perfect codes, the 3 antenna Threaded
Algebraic Space-Time code and the 4 antenna rate 2 code of Srinath and Rajan
are all full-diversity ACZF/ACZF-SIC decodable with complexity strictly less
than that of their ML decoders. Simulations show that the proposed decoding
method performs identical to ML decoding for all these five codes. These STBCs
along with the proposed decoding algorithm outperform all known codes in terms
of decoding complexity and error performance for 2,3 and 4 transmit antennas.
We further provide a lower bound on the complexity of full-diversity
ACZF/ACZF-SIC decoding. All the five codes listed above achieve this lower
bound and hence are optimal in terms of minimizing the ACZF/ACZF-SIC decoding
complexity. Both ACZF and ACZF-SIC decoders are amenable to sphere decoding
implementation.Comment: 11 pages, 4 figures. Corrected a minor typographical erro
Distributed space time block coding in asynchronous cooperative relay networks
The design and analysis of various distributed space time block coding
schemes for asynchronous cooperative relay networks is considered
in this thesis. Rayleigh frequency flat fading channels are assumed to
model the links in the networks, and interference suppression techniques
together with an orthogonal frequency division multiplexing type transmission
approach are employed to mitigate the synchronization errors
at the destination node induced by the different delays through the
relay nodes.
Closed-loop space time block coding is first considered in the context
of decode-and-forward (regenerative) networks. In particular, quasi orthogonal
and extended orthogonal coding techniques are employed for
transmission from four relay nodes and parallel interference cancellation
detection is exploited to mitigate synchronization errors. Availability
of a direct link between the source and destination nodes is studied,
and a new Alamouti space time block coding technique with parallel
interference cancellation detection which does not require such a direct
link connection and employs two relay nodes is proposed. Outer
coding is then added to gain further improvement in end-to-end performance
and amplify-and-forward (non regenerative) type networks
together with distributed space time coding are considered to reduce
relay node complexity.
Novel detection schemes are then proposed for decode-and-forward
networks with closed-loop extended orthogonal coding which reduce
the computational complexity of the parallel interference cancellation.
Both sub-optimum and near-optimum detectors are presented for relay
nodes with single or dual antennas. End-to-end bit error rate simulations
confirm the potential of the approaches and their ability to
mitigate synchronization errors. A relay selection approach is also formulated
which maximizes spatial diversity gain and attains robustness
to timing errors.
Finally, a new closed-loop distributed extended orthogonal space
time block coding solution for amplify-and-forward type networks which
minimizes the number of feedback bits by using a cyclic rotation phase
is presented. This approach utilizes an orthogonal frequency division
multiplexing type transmission structure with a cyclic prefix to mitigate
synchronization errors. End-to-end bit error performance evaluations
verify the efficacy of the scheme and its success in overcoming synchronization
errors
Distributed space time block coding and application in cooperative cognitive relay networks
The design and analysis of various distributed space time block coding
schemes for cooperative relay networks is considered in this thesis.
Rayleigh frequency flat and selective fading channels are assumed to
model the links in the networks, and interference suppression techniques
together with an orthogonal frequency division multiplexing (OFDM)
type transmission approach are employed to mitigate synchronization
errors at the destination node induced by the different delays through
the relay nodes.
Closed-loop space time block coding is first considered in the context
of decode-and-forward (regenerative) networks. In particular, quasi orthogonal
and extended orthogonal coding techniques are employed for
transmission from four relay nodes and parallel interference cancellation
detection is exploited to mitigate synchronization errors. Availability
of a direct link between the source and destination nodes is studied.
Outer coding is then added to gain further improvement in end-to-end
performance and amplify-and-forward (non regenerative) type networks
together with distributed space time coding are considered to reduce
relay node complexity. A novel detection scheme is then proposed
for decode-and-forward and amplify-and-forward networks with closed-loop
extended orthogonal coding and closed-loop quasi-orthogonal coding
which reduce the computational complexity of the parallel interference cancellation. The near-optimum detector is presented for relay
nodes with single or dual antennas. End-to-end bit error rate simulations
confirm the potential of the approach and its ability to mitigate
synchronization errors
Achieving Low-Complexity Maximum-Likelihood Detection for the 3D MIMO Code
The 3D MIMO code is a robust and efficient space-time block code (STBC) for
the distributed MIMO broadcasting but suffers from high maximum-likelihood (ML)
decoding complexity. In this paper, we first analyze some properties of the 3D
MIMO code to show that the 3D MIMO code is fast-decodable. It is proved that
the ML decoding performance can be achieved with a complexity of O(M^{4.5})
instead of O(M^8) in quasi static channel with M-ary square QAM modulations.
Consequently, we propose a simplified ML decoder exploiting the unique
properties of 3D MIMO code. Simulation results show that the proposed
simplified ML decoder can achieve much lower processing time latency compared
to the classical sphere decoder with Schnorr-Euchner enumeration
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