19,977 research outputs found
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
Joint Design of Overlaid Communication Systems and Pulsed Radars
The focus of this paper is on co-existence between a communication system and
a pulsed radar sharing the same bandwidth. Based on the fact that the
interference generated by the radar onto the communication receiver is
intermittent and depends on the density of scattering objects (such as, e.g.,
targets), we first show that the communication system is equivalent to a set of
independent parallel channels, whereby pre-coding on each channel can be
introduced as a new degree of freedom. We introduce a new figure of merit,
named the {\em compound rate}, which is a convex combination of rates with and
without interference, to be optimized under constraints concerning the
signal-to-interference-plus-noise ratio (including {\em signal-dependent}
interference due to clutter) experienced by the radar and obviously the powers
emitted by the two systems: the degrees of freedom are the radar waveform and
the afore-mentioned encoding matrix for the communication symbols. We provide
closed-form solutions for the optimum transmit policies for both systems under
two basic models for the scattering produced by the radar onto the
communication receiver, and account for possible correlation of the
signal-independent fraction of the interference impinging on the radar. We also
discuss the region of the achievable communication rates with and without
interference. A thorough performance assessment shows the potentials and the
limitations of the proposed co-existing architecture
Efficient Spectrum Sharing Between Coexisting OFDM Radar and Downlink Multiuser Communication Systems
This paper investigates the problem of joint subcarrier and power allocation
in the coexistence of radar and multi-user communication systems. Specifically,
in our research scenario, the base station (BS) provides information
transmission services for multiple users while ensuring that its interference
to a separate radar system will not affect the radar's normal function. To this
end, we propose a subcarrier and power allocation scheme based on orthogonal
frequency division multiple access (OFDM). The original problem consisting
involving multivariate fractional programming and binary variables is highly
non-convex. Due to its complexity, we relax the binary constraint by
introducing a penalty term, provided that the optimal solution is not affected.
Then, by integrating multiple power variables into one matrix, the original
problem is reformulated as a multi-ratio fractional programming (FP) problem,
and finally a quadratic transform is employed to make the non-convex problem a
sequence of convex problems. The numerical results indicate the performance
trade-off between the multi-user communication system and the radar system, and
notably that the performance of the communication system is not improved with
power increase in the presence of radar interference beyond a certain
threshold. This provides a useful insight for the energy-efficient design of
the system.Comment: 6 pages, 5 figure
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