“…Fortunately, the mmWave and the emerging THz bands can considerably overcome this shortcoming by providing an extra 3.25 GHz and 10-100 GHz bandwidth, respectively [38]. It is also expected that modern wireless user devices will be equipped with advanced capabilities that enable them to aggregate all these three frequency bands, i.e., the sub 6GHz, mmWave, and THz, to support future disruptive technologies and services [39]. However, allocating and managing the radio channels across these three frequency bands across multi-RAN to a massive number of user devices mandate developing advanced signal processing techniques.…”