LTE物理层天线端口问题讨论
1、PBCH配置的天线端口是不是一定要与小区参考信号的天线端口一样？即是不是当小区参考信号配置成天线端口0时，PBCH也配置成天线端口0；当小区配置成天线端口0，1时，PBCH也配置成天线端口0，1；当小区配置成天线端口0，1，2，3时，PBCH也同样配置
2、主同步信号发送时，3GPP协议中并没有特别明确规定采用哪个天线端口，那基站应该如何处理呢？将主同步信号在每个天线端口都发送一次？（另外，同步信号由Zadoff-Chu序列及小区ID生成，各位有没有关于ZC序列的硬件实现方案？）
3、Release 9有9个天线端口，支持4根物理天线，那这9个天线端口与物理天线有什么联系？
4、LTE物理层最后的OFDM基带生成，协议中的公式与天线端口有关，是不是可以理解为每个天线端口各自，且同时做OFDM基带生成，互不相干呢？
1, CRC bits for PBCH are scrambled according to antenna port configuration which is speicifed in Section 5.3.1.1 of 3GPP 36.212. Generally, PBCH and CRS use the same antenna ports, however, it doesnot mean that antenna mapping of PBCH is with respect to CRS.
2, Generally, two options may be taken. Firstly, PSS/SSS can be sent only on antenna port 0, and secondly, PSS/SSS can use PVS(Precoding Vector Switch) to perform antenna mapping which means that antenna port is selected alternatively.
3, 3GPP protocol indeed defines 9 antenna ports, but it does not specify anything about physical antenna number. There may be 1/2/4/6/8/.. physical antennas anyway. Antenna port is a logical concept, you can simply consider that each individual antenna port corresponding to a specific reference signal. For example, antenna port 0/1/2/3 takes R0~R3 individually for CRS, antenna port 4 take R4 for MBSFN RS, antenna port 5 takes R5 for TM7 DRS, antenna port 6 takes R6 for positioning RS and antenna port 7/8 takes R7/R8 for TM8 DRS.
4, I think so.
高手！
回复 2# 的帖子
Thank you very much~
But，Whats TM7 DRS？Can you explain?
DRS(Dedicated Reference Signal) is the UE-specific RS that transmitted along with PDSCH when TM7(i.e. Single Layer Beamforming using antenna port 5) is configured. The main function of DRS is for channel estimation.
“however, it doesnot mean that antenna mapping of PBCH is with respect to CRS.”
这句话怎样理解？“antenna mapping”是指antenna port到物理天线的映射吗？什么叫PBCH的antenna mapping不respect to CRS？
回复 2# 的帖子
不错。
高手啊
天线口port只和参考信号相关，不是真正的天线，有些广播信号只支持2天线的分集，叫SFBC啥来着？