7 research outputs found
Photonics-assisted analog wideband self-interference cancellation for in-band full-duplex MIMO systems with adaptive digital amplitude and delay pre-matching
A photonics-assisted analog wideband RF self-interference (SI) cancellation
and frequency downconversion approach for in-band full-duplex (IBFD)
multiple-input multiple-output (MIMO) systems with adaptive digital amplitude
and delay pre-matching is proposed based on a dual-parallel Mach-Zehnder
modulator (DP-MZM). In each MIMO receiving antenna, the received signal,
including different SI signals from different transmitting antennas and the
signal of interest, is applied to one arm of the upper dual-drive Mach-ehnder
modulator (DD-MZM) of the DP-MZM, the reference signal is applied to the other
arm of the upper DD-MZM, and the local oscillator signal is applied to the
lower DD-MZM. The SI signals are canceled in the optical domain in the upper
DD-MZM and the frequency downconversion is achieved after photodetection. To
cancel the SI signals, the reference signal is constructed in the digital
domain, while the amplitude and delay of the constructed reference are adjusted
digitally by upsampling with high accuracy. Experiments are performed when two
different SI signals are employed. The genetic algorithm and least-squares
algorithm are combined with segmented searching respectively for the SI signal
reconstruction and amplitude and delay pre-matching. A cancellation depth of
around 20 dB is achieved for the 1-Gbaud 16 quadrature-amplitude modulation
orthogonal frequency-division multiplexing signal.Comment: 25 pages, 17 figure
Nonlinear self-interference cancellation in MIMO full-duplex transceivers under crosstalk
This paper presents a novel digital self-interference canceller for an inband multiple-input-multiple-output (MIMO) full-duplex radio. The signal model utilized by the canceller is capable of modeling the in-phase quadrature (IQ) imbalance, the nonlinearity of the transmitter power amplifier, and the crosstalk between the transmitters, thereby being the most comprehensive signal model presented thus far within the full-duplex literature. Furthermore, it is also shown to be valid for various different radio frequency (RF) cancellation solutions. In addition to this, a novel complexity reduction scheme for the digital canceller is also presented. It is based on the widely known principal component analysis, which is used to generate a transformation matrix for controlling the number of parameters in the canceller. Extensive waveform simulations are then carried out, and the obtained results confirm the high performance of the proposed digital canceller under various circuit imperfections. The complexity reduction scheme is also shown to be capable of removing up to 65% of the parameters in the digital canceller, thereby significantly reducing its computational requirements.publishedVersionPeer reviewe
Full duplex-transceivers : architectures and performance analysis
PhD ThesisThe revolution of the 5G communication systems will result in 10,000 times increase
in the total mobile broadband traffic in the 2020s, which will increase the
demand on the limited wireless spectrum. This has highlighted the need for an
efficient frequency-reuse technique that can meet the ever-increasing demand on
the available frequency resources. In-band full-duplex (FD) wireless technology
that enables the transceiver nodes to transmit and receive simultaneously over the
same frequency band, has gained tremendous attention as a promising technology
to double the spectral efficiency of the traditional half-duplex (HD) systems. However,
this technology faces a formidable challenge, that is the large power difference
between the self-interference (SI) signal and the signal of interest from a remote
transceiver node. In this thesis, we focus on the architecture of the FD transceivers
and investigate their ability to approximately double the throughput and the spectral
efficiency of the conventional HD systems. Moreover, this thesis is concerned with
the design of efficient self-interference cancellation schemes that can be combined
with the architecture of the FD transceiver nodes in order to effectively suppress the
SI signal and enable the FD mode. In particular, an orthogonal frequency-division
multiplexing (OFDM) based amplify-and-forward (AF) FD physical-layer network
coding (PLNC) system is proposed. To enable the FD mode in the proposed system,
a hybrid SIC scheme that is a combination of passive SIC mechanism and
active SIC technique is exploited at each transceiver node of that system. Next, we
propose an adaptive SIC scheme, which utilizes the normalized least-mean-square
(NLMS) algorithm to effectively suppress the SI signal to the level of the noise
floor. The proposed adaptive SIC is then utilized in a denoise-and-forward (DNF)
FD-PLNC system to enable the FD mode. Finally, we introduce a novel overthe-
air SIC scheme that can effectively mitigate the SI signal before it arrives the
local analog-to-digital converter (ADC) of the FD transceiver nodes. Furthermore,
the impact of the hardware impairments on the performance of the introduced SIC
scheme is examined and characterized.Iraq, and the Ministry of
Higher Education and Scientific Research (MOHSR