NR系统中下行物理信号有哪些()
A.辅同步信号(Secondary synchronization si gnal, SSS)
B.信道状态信息参考信号(Channel -state information reference signal, CSI -RS)
C.解调参考信号(Demodulation reference signals, DM-RS)
D.相位跟踪参考信号(Phase-tracking reference signals, PT-RS)
E.主同步信号(Primary synchronization signal, PSS)