94,653 research outputs found
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
Cancellation of Power Amplifier Induced Nonlinear Self-Interference in Full-Duplex Transceivers
Recently, full-duplex (FD) communications with simultaneous transmission and
reception on the same channel has been proposed. The FD receiver, however,
suffers from inevitable self-interference (SI) from the much more powerful
transmit signal. Analogue radio-frequency (RF) and baseband, as well as digital
baseband, cancellation techniques have been proposed for suppressing the SI,
but so far most of the studies have failed to take into account the inherent
nonlinearities of the transmitter and receiver front-ends. To fill this gap,
this article proposes a novel digital nonlinear interference cancellation
technique to mitigate the power amplifier (PA) induced nonlinear SI in a FD
transceiver. The technique is based on modeling the nonlinear SI channel, which
is comprised of the nonlinear PA, the linear multipath SI channel, and the RF
SI canceller, with a parallel Hammerstein nonlinearity. Stemming from the
modeling, and appropriate parameter estimation, the known transmit data is then
processed with the developed nonlinear parallel Hammerstein structure and
suppressed from the receiver path at digital baseband. The results illustrate
that with a given IIP3 figure for the PA, the proposed technique enables higher
transmit power to be used compared to existing linear SI cancellation methods.
Alternatively, for a given maximum transmit power level, a lower-quality PA
(i.e., lower IIP3) can be used.Comment: To appear in proceedings of the 2013 Asilomar Conference on Signals,
Systems & Computer
Digital Predistortion in Large-Array Digital Beamforming Transmitters
In this article, we propose a novel digital predistortion (DPD) solution that
allows to considerably reduce the complexity resulting from linearizing a set
of power amplifiers (PAs) in single-user large-scale digital beamforming
transmitters. In contrast to current state-of-the art solutions that assume a
dedicated DPD per power amplifier, which is unfeasible in the context of large
antenna arrays, the proposed solution only requires a single DPD in order to
linearize an arbitrary number of power amplifiers. To this end, the proposed
DPD predistorts the signal at the input of the digital precoder based on
minimizing the nonlinear distortion of the combined signal at the intended
receiver direction. This is a desirable feature, since the resulting emissions
in other directions get partially diluted due to less coherent superposition.
With this approach, only a single DPD is required, yielding great complexity
and energy savings.Comment: 8 pages, Accepted for publication in Asilomar Conference on Signals,
Systems, and Computer
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Incorporating Digital Repeaters into the Soft Handover Standard in Digital Video Broadcasting Handheld
Digital Video Broadcasting for Handhelds (DVB-H) is a standard for broadcasting IP data services to portable devices. Handover in unidirectional broadcast networks is a novel issue introduced by this technology. This paper proposes and analyses the Repeater Aided Soft Handover (RA_handover) algorithm for a DVB-H receiver with MIMO antennas and presents the benefits of implementing RA_handover compared with a handover process without repeaters. For network planning and optimisation purposes simulation models are developed to analyse the RA_handover approach. It is shown that RA_handover could greatly improve the quality of service and consume much less front-end battery power than a handover method without repeaters. In addition, the cost introduced by the algorithm is briefly estimated. In conclusion, curves are given that show the relationship between quality of service and consumed battery power, which provide further support for including RA_handover in the DVB-H soft handover standard. The paper provides valuable outcomes for service providers and standard policy makers
Feasibility of In-band Full-Duplex Radio Transceivers with Imperfect RF Components: Analysis and Enhanced Cancellation Algorithms
In this paper we provide an overview regarding the feasibility of in-band
full-duplex transceivers under imperfect RF components. We utilize results and
findings from the recent research on full-duplex communications, while
introducing also transmitter-induced thermal noise into the analysis. This
means that the model of the RF impairments used in this paper is the most
comprehensive thus far. By assuming realistic parameter values for the
different transceiver components, it is shown that IQ imaging and
transmitter-induced nonlinearities are the most significant sources of
distortion in in-band full-duplex transceivers, in addition to linear
self-interference. Motivated by this, we propose a novel augmented nonlinear
digital self-interference canceller that is able to model and hence suppress
all the essential transmitter imperfections jointly. This is also verified and
demonstrated by extensive waveform simulations.Comment: 7 pages, presented in the CROWNCOM 2014 conferenc
A Software Defined Radio Platform with Direct Conversion: SOPRANO
A new software defined radio platform with multiport-based direct conversion is proposed, named SOPRANO (Software Programmable and Hardware Reconfigurable Architecture for Network). The main features of SOPRANO are a high-level design methodology for digital circuits, a new mixer-less direct conversion method, and software algorithms for multi-band and multi-mode operation. We built the first prototype SOPRANO 1.0, which was able to receive PSK and QAM signals with two different carrier frequencies at 2.45 GHz and 5.25 GHz by changing signal processing software
Modeling and Efficient Cancellation of Nonlinear Self-Interference in MIMO Full-Duplex Transceivers
This paper addresses the modeling and digital cancellation of
self-interference in in-band full-duplex (FD) transceivers with multiple
transmit and receive antennas. The self-interference modeling and the proposed
nonlinear spatio-temporal digital canceller structure takes into account, by
design, the effects of I/Q modulator imbalances and power amplifier (PA)
nonlinearities with memory, in addition to the multipath self-interference
propagation channels and the analog RF cancellation stage. The proposed
solution is the first cancellation technique in the literature which can handle
such a self-interference scenario. It is shown by comprehensive simulations
with realistic RF component parameters and with two different PA models to
clearly outperform the current state-of-the-art digital self-interference
cancellers, and to clearly extend the usable transmit power range.Comment: 7 pages, 5 figures. To be presented in the 2014 International
Workshop on Emerging Technologies for 5G Wireless Cellular Network
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