470 research outputs found
Towards Dual-functional Radar-Communication Systems: Optimal Waveform Design
We focus on a dual-functional multi-input-multi-output (MIMO)
radar-communication (RadCom) system, where a single transmitter communicates
with downlink cellular users and detects radar targets simultaneously. Several
design criteria are considered for minimizing the downlink multi-user
interference. First, we consider both the omnidirectional and directional
beampattern design problems, where the closed-form globally optimal solutions
are obtained. Based on these waveforms, we further consider a weighted
optimization to enable a flexible trade-off between radar and communications
performance and introduce a low-complexity algorithm. The computational costs
of the above three designs are shown to be similar to the conventional
zero-forcing (ZF) precoding. Moreover, to address the more practical constant
modulus waveform design problem, we propose a branch-and-bound algorithm that
obtains a globally optimal solution and derive its worst-case complexity as a
function of the maximum iteration number. Finally, we assess the effectiveness
of the proposed waveform design approaches by numerical results.Comment: 13 pages, 10 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
Cooperative Radar and Communications Signaling: The Estimation and Information Theory Odd Couple
We investigate cooperative radar and communications signaling. While each
system typically considers the other system a source of interference, by
considering the radar and communications operations to be a single joint
system, the performance of both systems can, under certain conditions, be
improved by the existence of the other. As an initial demonstration, we focus
on the radar as relay scenario and present an approach denoted multiuser
detection radar (MUDR). A novel joint estimation and information theoretic
bound formulation is constructed for a receiver that observes communications
and radar return in the same frequency allocation. The joint performance bound
is presented in terms of the communication rate and the estimation rate of the
system.Comment: 6 pages, 2 figures, to be presented at 2014 IEEE Radar Conferenc
MU-MIMO Communications with MIMO Radar: From Co-existence to Joint Transmission
Beamforming techniques are proposed for a joint multi-input-multi-output
(MIMO) radar-communication (RadCom) system, where a single device acts both as
a radar and a communication base station (BS) by simultaneously communicating
with downlink users and detecting radar targets. Two operational options are
considered, where we first split the antennas into two groups, one for radar
and the other for communication. Under this deployment, the radar signal is
designed to fall into the null-space of the downlink channel. The communication
beamformer is optimized such that the beampattern obtained matches the radar's
beampattern while satisfying the communication performance requirements. To
reduce the optimizations' constraints, we consider a second operational option,
where all the antennas transmit a joint waveform that is shared by both radar
and communications. In this case, we formulate an appropriate probing
beampattern, while guaranteeing the performance of the downlink communications.
By incorporating the SINR constraints into objective functions as penalty
terms, we further simplify the original beamforming designs to weighted
optimizations, and solve them by efficient manifold algorithms. Numerical
results show that the shared deployment outperforms the separated case
significantly, and the proposed weighted optimizations achieve a similar
performance to the original optimizations, despite their significantly lower
computational complexity.Comment: 15 pages, 15 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
Joint Design of surveillance radar and MIMO communication in cluttered environments
In this study, we consider a spectrum sharing architecture, wherein a
multiple-input multiple-output communication system cooperatively coexists with
a surveillance radar. The degrees of freedom for system design are the transmit
powers of both systems, the receive linear filters used for pulse compression
and interference mitigation at the radar receiver, and the space-time
communication codebook. The design criterion is the maximization of the mutual
information between the input and output symbols of the communication system,
subject to constraints aimed at safeguarding the radar performance. Unlike
previous studies, we do not require any time-synchronization between the two
systems, and we guarantee the radar performance on all of the range-azimuth
cells of the patrolled region under signal-dependent (endogenous) and
signal-independent (exogenous) interference. This leads to a non-convex
problem, and an approximate solution is thus introduced using a block
coordinate ascent method. A thorough analysis is provided to show the merits of
the proposed approach and emphasize the inherent tradeoff among the achievable
mutual information, the density of scatterers in the environment, and the
number of protected radar cells.Comment: Submitted to IEEE Transaction on Signal Processing on June 24, 201
Cooperative multiterminal radar and communication: a new paradigm for 6G mobile networks
The impending spectrum congestion imposed by the emergence of new
bandwidth-thirsty applications may be mitigated by the integration of radar and
classic communications functionalities in a common system. Furthermore, the
merger of a sensing component into wireless communication networks has raised
interest in recent years and it may become a compelling design objective for
6G. This article presents the evolution of the hitherto separate radar and
communication systems towards their amalgam known as a joint radar and
communication (RADCOM) system. Explicitly, we propose to integrate a radio
sensing component into 6G. We consider an ultra-dense network (UDN) scenario
relying on an active multistatic radar configuration and on cooperation between
the access points across the entire coverage area. The technological trends
required to reach a feasible integration, the applications anticipated and the
open research challenges are identified, with an emphasis on high-accuracy
network synchronization. The successful integration of these technologies would
facilitate centimeter-level resolution, hence supporting compelling
high-resolution applications for next-generation networks, such as robotic cars
and industrial assembly lines.publishe
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