Towards Optimal Association of Coexisting RF, THz and mm Wave Users in 6G Networks

The sixth generation (6G) mobile communication system is expected to utilize millimeter wave and THz frequency bands, in addition to RF bands. The propagation characteristics and ranges of these bands vary vastly while the multi-band users supposedly experience seamless coverage, high throughput and consistent Quality of Service. Heterogeneous base stations (BSs) equipped with these multiple technologies shall be fairly loaded for this. SINR based approaches tend to assign more users to RF channels while starving other bandwidth rich mediums. In this paper, we propose an algorithm to improve the performance of multi-band 6G networks by optimizing the user association to heterogeneous BS to maximize the cumulative data rate while ensuring an acceptable transmission power and fair load balancing among the BSs. The optimization problem is solved using the Lagrangian method. Simulation results show an improved cumulative throughput and fairness.