Uplink and Downlink Decoupling for Enhancing 5G Coverage
The higher frequency leads to larger penetration loss and poor coverage. For example, 3.5 GHz (as the first commercially used 5G band), provides insufficient coverage. There is a 13.7 dB gap in the uplink coverage between the 3.5 GHz and 1.8 GHz bands and the traditional solution of increasing the number of sites is often implemented to help bridge this difference.
However, site acquisition is difficult and the cost is high. So uplink and downlink decoupling to efficiently solve this troubling dilemma.
Typically, 3.5 GHz is used in the downlink to transmit signals and 1.8 GHz or 3.5 GHz is used on the terminal side to send signals. This provides the same uplink and downlink coverage as that of1.8 GHz.
Source: Huawei