Mobile operators are looking to carrier aggregation (CA), which allows them to use multiple sub-6 GHz spectrum channels simultaneously, as a method of increasing the bandwidth and speeds of their 5G networks. However, to enhance the performance of 5G networks even further, equipment vendors such as Ericsson and Qualcomm have been exploring FDD/TDD carrier aggregation.
FDD, or Frequency Division Duplex, and TDD, or Time Division Duplex, are two different spectrum usage techniques employed by mobile operators. While FDD uses separate frequencies for the uplink and the downlink, TDD uses a single frequency for both uplink and downlink, and therefore, they transmit at different times, making it more suitable when paired spectrum is not available.
