Talk at the PIRMC 2020 conferenceOFDM-based Spatial Data Focusing for High Resolution 2 Dimensional Wireless Geocasting
An OFDM-based Spatial Data Focusing (OFDM-SDF) approach is proposed as an improvement over standard Time-based Spatial Data Focusing (T-SDF) as a means of wirelessly broadcasting information towards confined spatial locations, i.e. wireless geocasting. It is shown that this approach allows for 2-dimensional focusing, hence leading to far greater flexibility in terms of geocasting scenarios compared to T-SDF and beamforming, both limited to angular focusing only. This increased flexibility does not come at any trade-off costs in terms of spatial selectivity, and hence, just as T-SDF, OFDM-SDF is shown to establish a considerable increase in attainable geocasting accuracy when compared to traditional power focusing methods. This paper describes the free space OFDM-SDF system model for uniform linear antenna arrays, including beamsteering and sidelobe mitigation techniques. Based on simulations, the performance of OFDM-SDF is compared to both T-SDF, as well as classical beamforming.
Talk at the GLOBECOM 2022 conferenceFrequency Diverse Array Spatial Data Focusing for High Precision Range-angle-based Geocasting
A unified frequency diverse array (FDA) and spatial data focusing (SDF) system, or FDA-SDF, is proposed as a novel approach to perform spatially confined broadcasting of information, i.e. geocasting. It is shown that SDF processing exploits FDA range-angle-dependency more effectively than conventional power focusing implementations, resulting in improved spatial focusing precision and reduced array size. Additionally, the time-variance flaw in conventional FDAs is addressed and mitigated by introducing a generalized baseband FDA model. This paper describes the FDA-SDF system model in free space, including dedicated SDF precoding, beamsteering, and equalization, exploiting FDA multi-frequency transmission for 2-dimensional range-angle-based time-invariant geocasting. Simulations of the FDA-SDF system illustrate compatibility with conventional FDA frequency offset schemes and highlight degrees of freedom for geocast delivery zone manipulation. Finally, FDA-SDF’s superior spatial precision is demonstrated: a 3-antenna FDA-SDF setup matches the radial and angular precision of a conventional FDA using, respectively, 13 and 23 antennas.