529 research outputs found
Co-existence Between a Radar System and a Massive MIMO Wireless Cellular System
In this paper we consider the uplink of a massive MIMO communication system
using 5G New Radio-compliant multiple access, which is to co-exist with a radar
system using the same frequency band. We propose a system model taking into
account the reverberation (clutter) produced by the radar system at the massive
MIMO receiver. Then, we propose several linear receivers for uplink
data-detection, ranging by the simple channel-matched beamformer to the
zero-forcing and linear minimum mean square error receivers for clutter
disturbance rejection. Our results show that the clutter may have a strong
effect on the performance of the cellular communication system, but the use of
large-scale antenna arrays at the base station is key to provide increased
robustness against it, at least as far as data-detection is concerned.Comment: To be presented at 2018 IEEE SPAWC, Kalamata, Greece, June 201
Waveform Design for 4D-Imaging mmWave PMCW MIMO Radars with Spectrum Compatibility
4D-imaging mmWave radars offer high angular resolution in both azimuth and elevation, but achieving this requires a large antenna aperture size and a significant number of transmit and/or receive channels. This presents a challenge
for designing transmit waveforms that are both orthogonal
and separable on the receive side, as well as have low
auto-correlation sidelobes. This paper focuses on designing an orthogonal set of sequences for 4D-imaging radar sensors based on PMCW technology. We propose an iterative optimization framework based on Coordinate Descent, which considers the Regions Of Interest (ROI) and optimizes a phase-modulated constant modulus waveform set based on weighted integrated sidelobe level on the required ROI and spectrum shaping. The optimization also accounts for the radar working adjacent to communication systems and other radar sensors. Simulation results are provided to demonstrate the effectiveness of the proposed method, which achieves low sidelobe levels and is compatible with spectrum constraints
Seventy Years of Radar and Communications: The Road from Separation to Integration
Radar and communications (R&C) as key utilities of electromagnetic (EM) waves have fundamentally shaped human society and triggered the modern information age. Although R&C have been historically progressing separately, in recent decades they have been moving from separation to integration, forming integrated sensing and communication (ISAC) systems, which find extensive applications in next-generation wireless networks and future radar systems. To better understand the essence of ISAC systems, this paper provides a systematic overview on the historical development of R&C from a signal processing (SP) perspective. We first interpret the duality between R&C as signals and systems, followed by an introduction of their fundamental principles. We then elaborate on the two main trends in their technological evolution, namely, the increase of frequencies and bandwidths, and the expansion of antenna arrays. Moreover, we show how the intertwined narratives of R\&C evolved into ISAC, and discuss the resultant SP framework. Finally, we overview future research directions in this field
Emerging Prototyping Activities in Joint Radar-Communications
The previous chapters have discussed the canvas of joint radar-communications
(JRC), highlighting the key approaches of radar-centric, communications-centric
and dual-function radar-communications systems. Several signal processing and
related aspects enabling these approaches including waveform design, resource
allocation, privacy and security, and intelligent surfaces have been elaborated
in detail. These topics offer comprehensive theoretical guarantees and
algorithms. However, they are largely based on theoretical models. A hardware
validation of these techniques would lend credence to the results while
enabling their embrace by industry. To this end, this chapter presents some of
the prototyping initiatives that address some salient aspects of JRC. We
describe some existing prototypes to highlight the challenges in design and
performance of JRC. We conclude by presenting some avenues that require
prototyping support in the future.Comment: Book chapter, 54 pages, 13 figures, 10 table
Co-Designing Statistical MIMO Radar and In-band Full-Duplex Multi-User MIMO Communications
We consider a spectral sharing problem in which a statistical (or widely
distributed) multiple-input-multiple-output (MIMO) radar and an in-band
full-duplex (IBFD) multi-user MIMO (MU-MIMO) communications system concurrently
operate within the same frequency band. Prior works on joint
MIMO-radar-MIMO-communications (MRMC) systems largely focus on either colocated
MIMO radars, half-duplex MIMO communications, single-user scenarios, omit
practical constraints, or MRMC co-existence that employs separate
transmit/receive units. In this paper, we present a co-design framework that
addresses all of these issues. In particular, we jointly design the statistical
MIMO radar codes, uplink (UL)/downlink (DL) precoders of in-band full-duplex
multi-user MIMO communications, and corresponding receive filters using our
proposed metric of compounded-and-weighted sum mutual information. This
formulation includes practical constraints of UL/DL transmit powers, UL/DL
quality-of-service, and peak-to-average-power ratio. We solve the resulting
highly non-convex problem through a combination of block coordinate descent and
alternating projection methods. Extensive numerical experiments show that our
methods achieve monotonic convergence in a few iterations, improve radar target
detection over conventional codes, and yield a higher achievable data rate than
standard precoders.Comment: 20 pages, 8 figures, 1 tabl
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