LTE FDD FRAME:
FDD Frame used for FDD technology.FDD is frequency division duplex which have different frequencies for both DL and UL at a same time. Below mentioned FDD frame. see 5G frame structure
1st Level
1 Radio Frame=10 ms
Short CP=140 ofdm symbols and Long CP=120 ofdm symbols
2nd Level
1 Sub frame=1ms
Short CP=14 ofdm symbols and Long CP=12 ofdm symbols
3rd Level
1 Time slot=0.5ms
Short CP=7 ofdm symbols and Long CP=6 ofdm symbols.
TIME UNIT IN LTE
· Ts(Standard Time in LTE)= 1/(15000*2048)sec-->32ns
v It’s a smallest unit of time in LTE operation
· Tslot=15360Ts=15360(1/(15000*2048))-->0.5ms
· A sub frame is equal to 30720Ts=1ms
· A Radio frame is equal to 307200Ts=10ms
· A radio frame = 20 Tslot
LTE TIME SLOT DIVISION
Time slot having two categories
· Short CP Time slot
· Long CP Time slot:
LTE TDD FRAME:
In TDD (Time division duplex) technique we are using, same frequency or frame for both DL and UL but at a different time.
· It consists in a category of Frame 2
· Radio frame size= 10 ms
· Sub-frame size= 1 ms
· Time slot size= 0.5 ms
· Each Radio frame consists two half frames.
TDD have a special sub frame (1,6) when downlink-to-uplink switch-point-periodicity is 5ms.
TDD have a special sub frame (1) when downlink-to-uplink switch-point-periodicity is 10ms.
Special Sub-frame carries following info:
DwPTS: Downlink pilot time slot
UpPTS: Uplink pilot time slot
Guard time: It is time using for switching from downlink to uplink so that interference can be eliminated.
LTE TDD UPLINK AND DOWNLINK CONFIGURATION: