Radio Channel Characterization for Distributed MIMO
Författare
Summary, in English
The third generation partner project (3GPP) has identified three different usage scenarios such as enhanced mobile broadband, massive machine-type communication, and ultra-reliable low latency communication.
In each of those scenarios, several services and applications can be implemented, e.g. vehicle-to-everything communication, localization, and positioning services.
In the fifth generation (5G) wireless communication standard, work has begun with the deployment of large multiple-input multiple-output (MIMO) systems.
With MIMO antenna arrays, we have unlocked the spatial domain and enabled spatial filtering and an increased number of users that can be served with the same time and frequency resources.
MIMO)arrays have also enabled us to mitigate deep fading dips due to small-scale fading through the channel hardening effect.
But to really achieve ultra-reliable links and in extension low-latency communication, the next natural step is to distribute the antenna array over a large spatial area, known as distributed MIMO (D-MIMO).
By distributing the antennas or arrays of antennas, the probability of having one or several access points with favorable propagation conditions is high.
In addition, the user will also be closer to infrastructure access points, leading to a decrease in the needed transmit power, and thus saving power.
The distribution of antennas also enhances positioning capabilities and enables users to be passively located using multistatic radar techniques based on the existing communication infrastructure.
This thesis explores a few different topics concerning the channel sounding and modeling of D-MIMO wireless channels, and then also using the acquired measurement data to evaluate the possibility for localization in a D-MIMO system and to sense passive users. The main topic is the design and implementation of a new multi-link channel sounder based on software-defined radios. The channel sounder records all possible link combinations between the distributed antennas, providing insight into dynamic multi-link channels. The recorded data enables offline processing to evaluate positioning algorithms and radar capabilities.
A new spatially consistent stochastic channel model is presented for an industrial environment with rich scattering. Large-scale parameters such as autocorrelation and covariance between infrastructure antennas are evaluated. A large-scale channel hardening effect is shown to be present when distributing the antennas, and it is shown that there is almost always at least one access point or antenna with good link properties.
The measurement data are also used to evaluate the possibilities for accurate positioning in a sub-6 GHz band with a bandwidth of 35 MHz. Using Doppler information (i.e., the carrier phase) and a maximum likelihood approach, we can achieve an accuracy of approximately 10 cm under line-of-sight conditions and 50 cm under obstructed line-of-sight conditions.
Avdelning/ar
Publiceringsår
2024-12-17
Språk
Engelska
Publikation/Tidskrift/Serie
Series of licentiate and doctoral theses
Issue
181
Fulltext
- Available as PDF - 17 MB
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Dokumenttyp
Doktorsavhandling
Förlag
Electrical and Information Technology, Lund University
Ämne
- Telecommunications
Aktiv
Published
Projekt
- ELLIIT LU P01: WP6 Vehicular communication
- WASP: Wallenberg AI, Autonomous Systems and Software Program at Lund University
Forskningsgrupp
- Communications Engineering
Handledare
ISBN/ISSN/Övrigt
- ISSN: 1654-790X
- ISBN: 978-91-8104-341-9
- ISBN: 978-91-8104-342-6
Försvarsdatum
31 januari 2025
Försvarstid
09:15
Försvarsplats
Lecture Hall E:1406, building E, Klas Anshelms väg 10, Faculty of Engineering LTH, Lund University, Lund. The dissertation will be live streamed, but part of the premises is to be excluded from the live stream.
Opponent
- Giovanni Del Galdo (Prof.)