转载:
LTE不同带宽配置下的对应的采样率:
< Sampling Time >
20 Mhz BW Case : Ts =1 sec / 30.72 Mhz = 1s/30,720,000 Hz = 0.0326 us = 32.6 ns
15 Mhz BW Case : T15= sec / 23.04 Mhz = 1s/23,040,000 Hz = 0.0434 us = 43.4 ns
10 Mhz BW Case : T10 = 1 sec / 15.36 Mhz = 1s/15,360,000 Hz = 0.0652 us = 65.2 ns
5 Mhz BW Case : T5 = 1 sec / 7.68 Mhz = 1s/7,680,000 Hz = 0.1302 us = 130.2 ns
3 Mhz BW Case : T3 = 1 sec / 3.84 Mhz = 1s/3,840,000 Hz = 0.2604 us = 260.4 ns
1.4 Mhz BW Case : T1.4= 1 sec / 1.92 Mhz = 1s/1,920,000 Hz = 0.5208 us = 520.8 ns
LTE基本的时间单位为Ts 定义为在20MHZ带宽,一个OFDM符号的周期为Ts=1/15000*2048 = 32.6ns。FFT size 为2048(100RB,1200SC)。采样频率为15kHz,那么20M带宽的采样率=15kHz*2048=3.072MHz。
其实也就是说对应于不同的BW,有对应于不同的sample time,
For example,one symbol: 20M,2048Ts;15M,1536 T15;10M,1024 T10;5M,512T5.
不同BW对应于有效的symbol长度都约等于66.7us:
20M:1 symbol = 2048 * Ts = 2048 * (1 sec / 2048*15K) 66.7us
15M:1 symbol = 1536 *T15 = 1536*(1 sec / 1536*15K) 66.7us
10M:1 symbol = 1024 * T10 =1024* 2* Ts = 1024 * (1 sec / 1024*15K) 66.7us
5M: 1 symbol = 512*T5 = 512* 4* Ts = 512* (1 sec / 512*15K) 66.7us
3M:1 symbol = 256 * T3 = 256* 8 * Ts= 256 * (1 sec / 256*15K) 66.7us
1.4M:1 symbol = 128*T1.4= 128* 16 * Ts= 128* (1 sec / 128*15K) 66.7us