Detection and channel estimation for channels with heavy interference.
2011-12
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Detection and channel estimation for channels with heavy interference.
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2011-12
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Abstract
Iterative decision-directed (DD) channel estimation (CE) and detection algorithms
for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing
(OFDM) systems are investigated. A main strength of the MIMO-OFDM is a potential
capability to support high data rates. However, interference between MIMO antennas has
been a serious obstacle to high data rate communication. Accurate channel state information
(CSI) is critical to reduce antenna interference and improve throughput performance
of the MIMO-OFDM communication systems. First, we develop soft-decision-driven sequential
CE algorithms specific to turbo equalization for the MIMO communication. Two
kinds of channel estimators are proposed: an optimal Kalman-based channel estimator
geared to the pipelined turbo equalizer and a low-complexity estimator design for practical
implementation. An effective strategy is established for the channel estimators dealing
with different qualities of feedback decisions from the turbo equalizer. The proposed
CE algorithms employ puncturing on observation samples to effectively deal with the inherent
correlated error input that cannot easily be removed by the traditional innovations
approach. Performance of the optimal estimator is excellent at compensating loss due to
imperfect CSI; however, computational complexity of the MIMO CE becomes a challenge
as the number of MIMO antenna links increases in practical systems. The proposed lowcomplexity
algorithm resolves the MIMO channel estimation problem into a single-input
single-output CE form to avoid heavy computation load associated with matrix operations.
Also, in order to reduce packet losses due to the inherent correlated error, a novel packet
recovery scheme is introduced that reprocesses failed packets by innovating on the inaccurate
CSI. The recovery scheme detects erroneous OFDM-symbol locations by comparing
extrinsic (EXT) information from the turbo equalizer. For the error correction, it applies
additional turbo iterations to the erroneous OFDM symbols with the innovated CSI. In
demonstrating the viability of the proposed schemes, a MIMO-OFDM communication system
is constructed to comply with the IEEE 802.11n WLAN standard.
Description
University of Minnesota Ph.D. dissertation. December 2011. Major: Electrical Engineering. Advisor: Professor Jaekyun Moon. 1 computer file (PDF); xi, 97 pages.
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Yoon, Daejung. (2011). Detection and channel estimation for channels with heavy interference.. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/120070.
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