• One of the advantages of using LTE TDD is that it is possible to dynamically change the up and downlink balance and characteristics to meet the load conditions.
  • In order that this can be achieved in an ordered fashion, a total of seven up / downlink configurations have been set within the LTE standards, in order to make possible.

D/ U is a subframe for downlink/ Uplink transmission and S is a “special” subframe used for a guard time.

  • In the case of the 5ms switch point periodicity, a special subframe exists in both half frames.
  • In the case of the 10 ms periodicity, the special subframe exists in the first half frame only.
  • It can be seen from the table below that the subframes 0 and 5 as well as DwPTS are always reserved for the downlink.
  • It can also be seen that UpPTS and the subframe immediately following the special subframe are always reserved for the uplink transmission.