96,383 research outputs found
All-Digital Self-interference Cancellation Technique for Full-duplex Systems
Full-duplex systems are expected to double the spectral efficiency compared
to conventional half-duplex systems if the self-interference signal can be
significantly mitigated. Digital cancellation is one of the lowest complexity
self-interference cancellation techniques in full-duplex systems. However, its
mitigation capability is very limited, mainly due to transmitter and receiver
circuit's impairments. In this paper, we propose a novel digital
self-interference cancellation technique for full-duplex systems. The proposed
technique is shown to significantly mitigate the self-interference signal as
well as the associated transmitter and receiver impairments. In the proposed
technique, an auxiliary receiver chain is used to obtain a digital-domain copy
of the transmitted Radio Frequency (RF) self-interference signal. The
self-interference copy is then used in the digital-domain to cancel out both
the self-interference signal and the associated impairments. Furthermore, to
alleviate the receiver phase noise effect, a common oscillator is shared
between the auxiliary and ordinary receiver chains. A thorough analytical and
numerical analysis for the effect of the transmitter and receiver impairments
on the cancellation capability of the proposed technique is presented. Finally,
the overall performance is numerically investigated showing that using the
proposed technique, the self-interference signal could be mitigated to ~3dB
higher than the receiver noise floor, which results in up to 76% rate
improvement compared to conventional half-duplex systems at 20dBm transmit
power values.Comment: Submitted to IEEE Transactions on Wireless Communication
On Phase Noise Suppression in Full-Duplex Systems
Oscillator phase noise has been shown to be one of the main performance
limiting factors in full-duplex systems. In this paper, we consider the problem
of self-interference cancellation with phase noise suppression in full-duplex
systems. The feasibility of performing phase noise suppression in full-duplex
systems in terms of both complexity and achieved gain is analytically and
experimentally investigated. First, the effect of phase noise on full-duplex
systems and the possibility of performing phase noise suppression are studied.
Two different phase noise suppression techniques with a detailed complexity
analysis are then proposed. For each suppression technique, both free-running
and phase locked loop based oscillators are considered. Due to the fact that
full-duplex system performance highly depends on hardware impairments,
experimental analysis is essential for reliable results. In this paper, the
performance of the proposed techniques is experimentally investigated in a
typical indoor environment. The experimental results are shown to confirm the
results obtained from numerical simulations on two different experimental
research platforms. At the end, the tradeoff between the required complexity
and the gain achieved using phase noise suppression is discussed.Comment: Published in IEEE transactions on wireless communications on
October-2014. Please refer to the IEEE version for the most updated documen
Self-Interference Cancellation with Nonlinear Distortion Suppression for Full-Duplex Systems
In full-duplex systems, due to the strong self-interference signal, system
nonlinearities become a significant limiting factor that bounds the possible
cancellable self-interference power. In this paper, a self-interference
cancellation scheme for full-duplex orthogonal frequency division multiplexing
systems is proposed. The proposed scheme increases the amount of cancellable
self-interference power by suppressing the distortion caused by the transmitter
and receiver nonlinearities. An iterative technique is used to jointly estimate
the self-interference channel and the nonlinearity coefficients required to
suppress the distortion signal. The performance is numerically investigated
showing that the proposed scheme achieves a performance that is less than 0.5dB
off the performance of a linear full-duplex system.Comment: To be presented in Asilomar Conference on Signals, Systems &
Computers (November 2013
Status and potential of aquaculture in small waterbodies (ponds and ditches) in Bangladesh
A report on a survey on ponds and ditches in Bangladesh, done to determine their potential use for aquaculture.Aquaculture, Fish culture, Freshwater aquaculture, Pond Culture, Water bodies, Ponds, Bangladesh,
Azimuthal anisotropy () of high-p and direct in Au+Au collisions at = 200 GeV
Preliminary results from the STAR collaboration of the azimuthal anisotropy
of and direct photon () at high transverse
momentum (p) from Au+Au collisions at center-of-mass energy
~GeV are presented. A shower-shape analysis is used to
select a sample free of direct photons () and a sample rich in direct
photons . The relative contribution of background in the
sample is determined assuming no associated charged particles
nearby . The of direct photons ()
at mid-rapidity () and high p (~GeV/) is extracted from those of and
neutral particles measured in the same kinematic range. In mid-central Au+Au
collisions (10-40), the of () and
charged particles () are found to be 0.12 and nearly
independent of p. The measured is positive
finite and systematically smaller than that of and charged particles
by a factor of 3. Although the large at such high
p might be partially due to the path-length dependence of energy loss,
the non-zero value of indicates a bias of the reaction
plane determination due to the presence of jets in the events. Systematic
studies are currently in progress.Comment: 4 pages, 2 figures, Hot Quarks 2010, LaLonde Franc
- β¦