Frame Structure in LTE

FDD Down-link Frame Structure in LTE

Source: http://www.sharetechnote.com/image/36_211_Fig4_1_1_FDD_DL_FrameStructure.PNG


1 Frame = 1 ms
1 Frame = 10 Sub-frame

1 Slot = 0.5 ms
2 Slot = 2*0.5 ms = 1 ms
2 Slot = 1 Sub-frame

1 Frame = 10 (Sub-frame) * 2  slots = 20 Slots





Source: http://www.sharetechnote.com/image/FDD_DL_FrameStructure_Symbols.PNG


1 Slot = 7 Symbols
(In case of Normal Cyclic Prefix, 6 in case of Extended Cyclic Prefix)

1 Symbol = 0.5(Duration of 1 slot) / 7 (Number of Symbol per slot) ms =  ~71.4 us
1 Symbol =  Cyclic Prefix + Data

First OFDM symbol is longer than the rest of the OFDM symbol in that slot.

First Symbol = 71.9 us  = 5.2 us+ 66.7 us
Rest Symbol = 71.3 us  = 4.7 us + 66.6 us

First Symbol (time) + 6*Rest Symbol (time) = 71.9 us  + 6*71.3 us = 71.9 us + 427.8 us = 499.7 us = ~500 us = 0.5 ms

The Number of sample we see here in below illustration is based on the sampling rate is 30.072 M Samples/Sec and 2048 bins/IFFT(N_ifft). Since real sampling rate and N_ifft varies depending on system BW, we need to scale this number according to a specific BW.




Source: http://www.sharetechnote.com/image/FDD_DL_FrameStructure_Subframe_01.PNG












Source :http://www.sharetechnote.com/image/PHY_CH_DL.PNG













Source: http://www.sharetechnote.com/image/LTE_DL_FrameStructure_01.png