All About LTE Radio Frame (FDD and TDD)

LTE Radio Frame: 
- Two Radio Frame Structures Supported.
- Type 1, applicable to FDD
- Type 2, applicable to TDD

Frame structure type 1:
- Applicable to both full duplex and half duplex FDD.
- Each radio frame is Tf = 307200 * Ts = 10ms long.
- Consists of 20 slots of lengthTslot = 15360*Ts = 0.5ms
- Numbered from 0 to 19
- A subframe is defined as two consecutive slots.
- Subframe i consists of slots 2i and 2i + 1.

Frame structure type 2:
- Each radio frame of length Tf  = 307200*Ts = 10ms long.
- Consists of two half-frames of length 153600*Ts = 5ms each
- Each half-frame consists of five subframes.

- The supported uplink-downlink configurations are listed below:

- Each subframe in a radio frame, “D” denotes the subframe is reserved for Downlink Transmissions.
- Each subframe in a radio frame, “U” denotes the subframe is reserved for Uplink Transmissions.
- Each subframe in a radio frame, “S” denotes the subframe is reserved for Special Subframe.
- Special Subframe consists of three fields DwPTS, GP and UpPTS.
- Both 5 ms and 10 ms downlink-to-uplink switch-point periodicity are supported.
- In case of 5 ms downlink-to-uplink switch-point periodicity, the special subframe exists in both half-frames.
- In case of 10 ms downlink-to-uplink switch-point periodicity, the special subframe exists in the first half-frame only.
- Subframes 0 and 5 and DwPTS are always reserved for downlink transmission.
- UpPTS and the subframe immediately following the special subframe are always reserved for uplink transmission.