PT Unknown
AU Steeg, M
TI Photonic-Assisted Beam Steering via Leaky-Wave Antennas for Wireless Communication and Radar
PD 05
PY 2021
DI 10.17185/duepublico/74265
LA en
DE Radar; Funkkommunikation; Wireless Communication; Radio-over-Fiber; Leckwellenantennen; Leaky-Wave Antennas; 5G; Mobilfunk; Mobile Communication; Photonic Transmitter; Radio access; Funkzugang; PCB Antenna; Leiterplattentechnologie; High data rate; 100 Gbit/s; Steerable antenna; Strahlsteuerung
AB Our globalized world of today requires high speed internet service for an ever-growing number of users. This trend can only be facilitated by a steady increase of communication capacity, especially for mobile and wireless services, which are now ubiquitous and amount to a large portion of network traffic. The next generation of mobile communication (5G) highlights future use case scenarios like high capacity hot-spots and defines key enabling performance parameters for 5G and beyond. Insofar, a 1000-fold capacity increase is projected via raising the bandwidth, number of cells and users as well as the spectral-efficiency. To achieve this goal, the mm-wave spectrum, offering multiple GHz of bandwidth, is very attractive, but necessitates the utilization of new steerable and directive antenna solutions. This thesis conceives a coherent solution for a 5G hot-spot based on mm-wave leakywave antennas (LWAs) in synergy with Radio-over-Fiber (RoF) fronthaul to offer the necessary fiber distribution. In contrast to digitized RoF, limited by its bandwidth capability, an efficient analog fronthaul is demonstrated, achieving a world-record 100 Gbit/s throughput in the 60 GHz band, by utilizing IF-OFDM coherent RoF transport. In combination with leaky-wave antenna beam scanning, an innovative photonic-assisted antenna solution, that provides multibeam steering with simple radio access units, is also presented. Therefore, periodic LWAs unit cells are investigated to design novel 60 GHz LWAs and 26 GHz LWAs based on laminates. The characterization of the developed PCB LWAs shows a realized gain of up to 15.4 dBi and quasi linear steering via the radio frequency (RF) in excess of 110°. Even a 26 GHz integrated photonic transmitter is demonstrated via the LWA integration of high-speed photodetectors and the further potential for photonic-integrated circuits to yield 2D LWA beam steering is outlined. The conducted fiber-wireless communication experiments show the flexibility and scalability of the LWA solution, that also enables low ≈ 0.4 ms latency and MAC layer controlled steering via integrated RF transceivers. Moreover, wireless access to 20 users is realized, delivering over 10 Gbit/s throughput using 6.1 GHz bandwidth and a single RF chain, fed via RoF fronthaul. The 5G hot-spot application is demonstrated live as part of a two week field trial, which features the transmission of two 1.5 Gbit/s video streams from a data center over 11 km optical fiber to a mobile unit in a public shopping mall. Additionally, even 10 Gbit/s user data rates are achieved using 32 QAM IF-OFDM signals in a fiber-wireless 60 GHz band link. Since beam steering for mobile access requires user localization, also a simple FMCW radar scheme for multiple user detection in the LWA coverage sector is developed. This approach is employed for an all photonic radar based on laser chirping, that even provides 3D localization. Finally, an innovative joint OFDM communication-radar system is presented that allows simultaneous wireless access for multiple users and their radar localization. Thereby, the OFDM preamble is exploited as a radar chirp to avoid spectrum division so that 5 × 4 Gbit/s wireless transmission as well as accurate localization is achieved.
ER