LTE frame structures used for TDD
36.211 frame structure type 2 (DL / UL / SSF)
Correct choice of Configuration value is essential when setting the UL/DL ratio for CableFree LTE networks using TDD bands
- Choose a configuration with more “D”s in the frame means greater proportion of Downlink Data (normal for most Internet /ISP applications)
- Choose a configuration with more “U”s in a frame when you need a greater proportion of Uplink Data. This is when most traffic is uplinked e.g. CCTV applications, from remote cameras to base
- Choose a configuration with equal “D” and “U” for a balanced network (equal up/down)
Configuration | 3GPP release |
Downlink to uplink switch point periodicity (ms) |
Subframe number | Number of subframes / frame | |||||||||||||
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | D [DL] | U [UL] | S [SSF] | |||||
0 | 8 | 5 | D | S | U | U | U | D | S | U | U | U | 2 | 6 | 2 | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 8 | 5 | D | S | U | U | D | D | S | U | U | D | 4 | 4 | 2 | ||
2 | 8 | 5 | D | S | U | D | D | D | S | U | D | D | 6 | 2 | 2 | ||
3 | 8 | 10 | D | S | U | U | U | D | D | D | D | D | 6 | 3 | 1 | ||
4 | 8 | 10 | D | S | U | U | D | D | D | D | D | D | 7 | 2 | 1 | ||
5 | 8 | 10 | D | S | U | D | D | D | D | D | D | D | 8 | 1 | 1 | ||
6 | 8 | 5 | D | S | U | U | U | D | S | U | U | D | 3 | 5 | 2 |
- D – Downlink subframe
- S – Special subframe (see below)
- U – Uplink subframe
Graphical view of one TDD frame (10ms)
SSF Special SubFrame, normal CP (Dw / GP / Up)
Configuration | 3GPP release |
DwPTS | UpPTS | Number of slots / subframe | |||
(Ts) | (Ts) | Dw | GP | Up | |||
0 | 8 | 6592 | 2192 | 3 | 10 | 1 | |
---|---|---|---|---|---|---|---|
1 | 8 | 19760 | 2192 | 9 | 4 | 1 | |
2 | 8 | 21952 | 2192 | 10 | 3 | 1 | |
3 | 8 | 24144 | 2192 | 11 | 2 | 1 | |
4 | 8 | 26336 | 2192 | 12 | 1 | 1 | |
5 | 8 | 6592 | 4384 | 3 | 9 | 2 | |
6 | 8 | 19760 | 4384 | 9 | 3 | 2 | |
7 | 8 | 21952 | 4384 | 10 | 2 | 2 | |
8 | 8 | 24144 | 4384 | 11 | 1 | 2 | |
9 | 11 | 13168 | 4384 | 6 | 6 | 2 |
- DwPTS – Downlink Pilot Time Slot
- UpPTS – Uplink Pilot Time Slot
- GP – Guard period
Graphical view of a Special Subframe (1ms)
For Further Information
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