OFDM-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.