Nr-prach:prach format and time-frequency domain

1.PRACH Format and characteristics of ：

Format 0~3 Used only for 6GHz following , It can support both unrestricted sets and restricted set types A&B;
Format0 Suitable for cell coverage with normal radius , Such as urban area , Rural and suburban environments .
Format1 Suitable for large cell radius , Like the sea , Desert and other environments .
Format2 Suitable for small delay spread , Scenes with large signal transmission loss , Such as deep coverage .
Format3 Insensitive to Doppler shift and phase noise , Therefore, it is suitable for high-speed scenes .
● Format A1~C2 It can also be used for 6GHz Below and above , Only unrestricted sets are supported , Restricted sets are not supported ;
● stay 6GHz The following support 15kHz and 30kHz Subcarrier spacing , stay 6GHz Above support 60kHz and 120kHz Subcarrier spacing .
Doppler adaptability ：
Restricted set type A The Doppler shift range that can be covered is [-1.25KHz,1.25KHz]
Restricted set type B The Doppler shift range that can be covered is [-2.5KHz,2.5KHz]
Restricted sets are only for Format0-3

2.prach Time domain of ：

prach Of ofdm Signal generation ：

This is frequency offset

This is time biased

prach occasion

With fmt0~3 For example

prach Corresponding subframe and symbol position

6.3.3.2-2 in the light of fdd.
6.3.3.2-3 Aiming at fdd 30khz And the following scenario of carrier spacing .
6.3.3.2-4 Aiming at fdd 30khz The above scenario .
With tdd in order to fmt0 For example ：

In subframe 9 Send on prach The starting symbol is 0, Yes fmt0~3 It takes up the whole subframe .
And yes fmtA1~C2 Come on , Here is the starting symbol position , adopt N_u You can see several symbols .

prach Frequency domain

system-wide prb The bandwidth of is based on pusch From the subcarrier spacing of , So I made a transformation here , real prach The total bandwidth occupied is prach Multiply the subcarrier interval of by L_RA.
General distribution prach Bandwidth on both sides , On the edge is pucch, Then is prach, In the middle pusch