Why is the minimum time unit of the LTE system TS?

have been doing the LTE physical layer related work, there has been a doubt, in 36.211 the beginning of a chapter defines the size of TS is 1/(15000*2048) s, why define so a strange unit time.

Recently, this was related to the FFT/IFFT process.

Assuming 20MHz bandwidth, the standard specifies that we use 2048 points to do the FFT process, the FFT process is the time domain, each time domain symbol has 2048 time domain sample, FFT, converted into the frequency domain of 2048 sample, the specific process is as follows:

A time domain symbol is 1/(14*1000) s, then our physical layer sampling rate is 2048*14*1000 (SAMPLES/S), gee, we found that it is close to TS (1/(15000*2048)), but where the problem arises? Thinking,thinking, thinking ...

So, cyclic prefix (loop prefix, CP) appears.

CP is a mechanism that LTE systems take to avoid inter-symbol interference, and we artificially add a piece of repetitive information to the transmitter before it launches the physical wave that each symbol represents, called CP. ：

The size of this length (7 symbols within a RB):

A tti (1ms) has two RB, one RB has 7 symbol, so there is a 2048*7+160+144*6 =15*2048 samples within 1ms,

So its sampling rate is 15*2048 *1000 samples/s (30.72MHz sampling). So we get our answer, a TS is a sample of the length of time. Ha ha!

Why is the minimum time unit of the LTE system TS?