ACCESS Seed project in Signals and Systems: Impairments in Radio Frequency Transceivers and Pilot
Design for correlated MIMO channels (RF-MIMO)
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Project leader: Per Zetterberg
ACCESS faculty: Per Zetterberg
ACCESS founding faculty Peter Händel, Håkan Hjalmarsson, Mats Bengtsson, Magnus Jansson
(#4):
PostDocs and PhD-students: Cristian Rojas, Senay Negusse
Deliverables: 5
Digital signal processing techniques are heavily used in wireless systems in order to increase data-rates
and the effective use of the available spectrum. Each new generation of wireless standards increases
the requirements of the analog radio frequency (RF) hardware. This increases the cost and power
consumption of the equipment. A new research trend is to reduce the power consumption – also
known as “green-radio”. One way of leveraging such improvements is to use digital signal processing
techniques to compensate for the impairments of analog components in digital base-band. This is
known as the dirty-radio paradigm. A few works are already available in the area; however, the volume
is still very modest in comparison with the thousands of articles that propose techniques that require
ever-increasing performance of analog components. Thus, we propose an ACCESS seed project in this
area. By our work, we apply our statistical modeling expertise into the area. Further, we aim to bring
more understanding of hardware impairments into our academic community. Our ACCESS wireless
test-bed will be used to collect measurements and prototype our methods.
Impairments of analog circuitry include I&Q imbalance, phase-noise, non-linearities and clock jitter.
We will focus on the first two issues. A list of expected deliverables are listed below. For the I&Q
imbalance assessment we will investigate the use of ellipse fitting methods. For tracking of phasenoise we will attempt at using Kalman and Particle filtering techniques.
Deliverables:
P. Händel, C. Rojas, P. Zetterberg and H. Hjalmarsson, "Ellipse fitting, IQ imbalance, and the Cramer
Rao Bound", IEEE transactions on Instrumentation and Measurements
S. Negusse S, P. Zetterberg, P. Händel P, C. Rojas and H Hjalmarsson, “Assessment and compensation of
phase-noise”, IEEE Transactions on Wireless systems
H. Hjalmarsson, C. Rojas, S. Negusse, P. Zetterberg, P. Händel, “Posterior CRB bounds for discrete-time
phase-noise filtering”, IEEE Transactions on Signal Processing.
Proper external excitation of the system is essential in many, if not all, estimation problems: sensing,
robotics, vision systems, system identification, communication systems, fault detection, the list can be
made very long. The objective of this project is to explore what ACCESS can deliver regarding the
problem of choosing the excitation such that the estimation problem at hand is facilitated, or even
optimized. We have an interesting mix of researchers in the project, representing non-linear systems,
system identification, communication systems, and systems theory. There is a strong emphasis on
cross-collaboration within the project. More specifically, we will continue our activities in pilot design
for correlated MIMO channels.
Deliverables:
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Paper 1: “Pilot design for correlated MIMO channels”, M. Bengtsson, M. Jansson, C.R. Rojas, X.
Bombois, H. Hjalmarsson,
Paper 2: “Adaptive experiment design”, C.R. Rojas, L. Gerencsér, M. Jansson, H. Hjalmarsson