2 research outputs found
Large MIMO Detection Schemes Based on Channel Puncturing: Performance and Complexity Analysis
A family of low-complexity detection schemes based on channel matrix
puncturing targeted for large multiple-input multiple-output (MIMO) systems is
proposed. It is well-known that the computational cost of MIMO detection based
on QR decomposition is directly proportional to the number of non-zero entries
involved in back-substitution and slicing operations in the triangularized
channel matrix, which can be too high for low-latency applications involving
large MIMO dimensions. By systematically puncturing the channel to have a
specific structure, it is demonstrated that the detection process can be
accelerated by employing standard schemes such as chase detection, list
detection, nulling-and-cancellation detection, and sub-space detection on the
transformed matrix. The performance of these schemes is characterized and
analyzed mathematically, and bounds on the achievable diversity gain and
probability of bit error are derived. Surprisingly, it is shown that puncturing
does not negatively impact the receive diversity gain in hard-output detectors.
The analysis is extended to soft-output detection when computing per-layer bit
log-likelihood ratios; it is shown that significant performance gains are
attainable by ordering the layer of interest to be at the root when puncturing
the channel. Simulations of coded and uncoded scenarios certify that the
proposed schemes scale up efficiently both in the number of antennas and
constellation size, as well as in the presence of correlated channels. In
particular, soft-output per-layer sub-space detection is shown to achieve a
2.5dB SNR gain at bit error rate in -QAM MIMO,
while saving of nulling-and-cancellation computations
Large Multiuser MIMO Detection: Algorithms and Architectures
In this thesis, we investigate the problem of efficient data detection in
large MIMO and high order MU-MIMO systems. First, near-optimal low-complexity
detection algorithms are proposed for regular MIMO systems. Then, a family of
low-complexity hard-output and soft-output detection schemes based on channel
matrix puncturing targeted for large MIMO systems is proposed. The performance
of these schemes is characterized and analyzed mathematically, and bounds on
capacity, diversity gain, and probability of bit error are derived. After that,
efficient high order MU-MIMO detectors are proposed, based on joint modulation
classification and subspace detection, where the modulation type of the
interferer is estimated, while multiple decoupled streams are individually
detected. Hardware architectures are designed for the proposed algorithms, and
the promised gains are verified via simulations. Finally, we map the studied
search-based detection schemes to low-resolution precoding at the transmitter
side in massive MIMO and report the performance-complexity tradeoffs.Comment: PhD dissertation - Hadi Sarieddee