A critical development in modern FDD is SUL. This technique utilizes underutilized FDD uplink spectrum to boost the uplink capacity of TDD carriers. By aggregating an FDD uplink carrier with a TDD carrier, network operators can solve the "uplink bottleneck" often seen in TDD-heavy 5G deployments.
: Success rates for users connecting to the network (e.g., target success rates often above 99%). fdd 2059