Combining Capacity and Reliability via Inter-Frequency Handovers

A potential use case for the sixth-generation wireless networks is the widespread adoption of eXtended Reality (XR) on mobile devices. These applications require high data rates, which may exhaust the limited available bandwidth ofmid-band(MB) frequencies, comprising frequency range 1 (FR1), i.e., sub-6 GHz, and the lower part of frequency range 3 (FR3), spanning 7-24 GHz, especially in dense urban clusters. In contrast, thehigh-band(HB) frequencies, including the frequency range 2 (FR2), i.e., millimeter-wave frequencies, and the upper part of FR3, offer more bandwidth, but are prone to reliability issues due to obstructions that block line-of-sight links between user equipment (UEs) and base stations (BSs). Therefore, we propose offloading high data rate UEs experiencing link outages in HB to MB. Using a cell-free massive multiple-input multiple-output architecture in MB, we ensure stable throughput for both low data rate UEs and offloaded high data rate UEs, while distributing the traffic load across more BSs. Our results demonstrate significant reduction in the mean outage duration and a hundred-fold reduction in the mean outage probability, with minimal impact on service quality for low data rate UEs, offering a cost-effective, practical solution for reliable HB deployments.