SpecTerA: Spatial-Spectral Access and Coordination in Terahertz Wireless Networks

Terahertz (THz) bands provide unprecedented bandwidth and exhibit angular dispersion, offering the potential to achieve the next order of magnitude in data rates and user densities. While THz-scale antennas such as Leaky Wave Antennas (LWAs) enable dynamic beamforming with inherent frequency-dependent beam steering and high directivity, their constrained usable bandwidth and low spectral efficiency in specific directions limit their ability to support high-density multi-user communication. We propose SpecTerA, a novel multi-user THz spatial-spectral access and coordination framework to overcome these challenges. SpecTerA incorporates a multi-LWA node architecture that utilizes statically engineered LWAs to generate frequency-differentiated radiative beams, addressing bandwidth fragmentation and enhancing angular coverage by aggregating spectrum across multiple LWAs. We explore how the geometry, count, and orientation of LWAs affect spatial coverage and spectral utilization, providing key design insights for meeting the demands of high-throughput, dynamic, and dense communication scenarios. We introduce various opportunistic, fairness-driven multi-user strategies to coordinate the multi-LWA architecture to ensure equitable and efficient spectrum utilization. Our physics-driven analytical evaluations demonstrate that SpecTerA significantly outperforms single-LWA links, boosting aggregate data rates and mitigating inter-user interference by opportunistically pooling bandwidth across multiple antennas or employing strategic antenna switching to adapt to user demands.