498 research outputs found
Self-Interference Cancellation Using Time-Domain Phase Noise Estimation in OFDM Full-Duplex Systems
In full-duplex systems, oscillator phase noise (PN) problem is considered the
bottleneck challenge that may face the self-interference cancellation (SIC)
stage especially when orthogonal frequency division multiplexing (OFDM)
transmission scheme is deployed. Phase noise degrades the SIC performance
significantly, if not mitigated before or during the SIC technique. The
presence of the oscillator phase noise has different impacts on the transmitted
data symbol like common phase error (CPE) and inter-carrier interference (ICI).
However, phase noise can be estimated and mitigated digitally in either time or
frequency domain. Through this work, we propose a novel and simple time domain
self-interference (SI) phase noise estimation and mitigation technique. The
proposed algorithm is inspired from Wiener filtering in time domain. Simulation
results show that the proposed algorithm has a superior performance than the
already-existing time-domain or frequency domain PN mitigation solutions with a
noticeable reduction in the computational complexity
Reference Receiver Based Digital Self-Interference Cancellation in MIMO Full-Duplex Transceivers
In this paper we propose and analyze a novel self-interference cancellation
structure for in-band MIMO full-duplex transceivers. The proposed structure
utilizes reference receiver chains to obtain reference signals for digital
self-interference cancellation, which means that all the transmitter-induced
nonidealities will be included in the digital cancellation signal. To the best
of our knowledge, this type of a structure has not been discussed before in the
context of full-duplex transceivers. First, we will analyze the overall
achievable performance of the proposed cancellation scheme, while also
providing some insight into the possible bottlenecks. We also provide a
detailed formulation of the actual cancellation procedure, and perform an
analysis into the effect of the received signal of interest on
self-interference coupling channel estimation. The achieved performance of the
proposed reference receiver based digital cancellation procedure is then
assessed and verified with full waveform simulations. The analysis and waveform
simulation results show that under practical transmitter RF/analog impairment
levels, the proposed reference receiver based cancellation architecture can
provide substantially better self-interference suppression than any existing
solution, despite deploying only low-complexity linear digital processing.Comment: 7 pages, 4 figures. To be presented in the 2014 IEEE Broadband
Wireless Access Worksho
Multi-tap Digital Canceller for Full-Duplex Applications
We identify phase noise as a bottleneck for the performance of digital
self-interference cancellers that utilize a single auxiliary
receiver---single-tap digital cancellers---and operate in multipath propagation
environments. Our analysis demonstrates that the degradation due to phase noise
is caused by a mismatch between the analog delay of the auxiliary receiver and
the different delays of the multipath components of the self-interference
signal. We propose a novel multi-tap digital self-interference canceller
architecture that is based on multiple auxiliary receivers and a customized
Normalized-Least-Mean-Squared (NLMS) filtering for self-interference
regeneration. Our simulation results demonstrate that our proposed architecture
is more robust to phase noise impairments and can in some cases achieve 10~dB
larger self-interference cancellation than the single-tap architecture.Comment: SPAWC 201
Hardware Impairments Aware Transceiver Design for Bidirectional Full-Duplex MIMO OFDM Systems
In this paper we address the linear precoding and decoding design problem for
a bidirectional orthogonal frequencydivision multiplexing (OFDM) communication
system, between two multiple-input multiple-output (MIMO) full-duplex (FD)
nodes. The effects of hardware distortion as well as the channel state
information error are taken into account. In the first step, we transform the
available time-domain characterization of the hardware distortions for FD MIMO
transceivers to the frequency domain, via a linear Fourier transformation. As a
result, the explicit impact of hardware inaccuracies on the residual
selfinterference (RSI) and inter-carrier leakage (ICL) is formulated in
relation to the intended transmit/received signals. Afterwards, linear
precoding and decoding designs are proposed to enhance the system performance
following the minimum-mean-squarederror (MMSE) and sum rate maximization
strategies, assuming the availability of perfect or erroneous CSI. The proposed
designs are based on the application of alternating optimization over the
system parameters, leading to a necessary convergence. Numerical results
indicate that the application of a distortionaware design is essential for a
system with a high hardware distortion, or for a system with a low thermal
noise variance.Comment: Submitted to IEEE for publicatio
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