请教大家个问题，LTE传输模式TM1-TM8中哪种属于MIMO模式

除了TM1都是MIMO

LTE Transmission Mode:
Transmission mode 1: Single-antenna transmission.
Transmission mode 2: Transmit diversity, SFBC(Space-Frequency Block Coding)based.
Transmission mode 3: Open-loop codebook-based precoding in the case of more than one layer, degraded to transmit diversity in the case of rank-one transmission. (SU-MIMO)
Transmission mode 4: Closed-loop codebook-based precoding. (SU-MIMO).
Transmission mode 5: Multi-user MIMO version of transmission mode 4 (up to max 2 users/layers).
Transmission mode 6: Special case of closed-loop codebook-based precoding limited to single layer transmission, also called beam-forming for single user.
Transmission mode 7: Release-8 non-codebook-based precoding supporting only single-layer transmission per UE, it is also called beam-forming here for single layer per UE.
Transmission mode 8: Release-9 non-codebook-based precoding supporting up to two layers per UE.
Transmission mode 9: Release-10 non-codebook-based precoding supporting up to eight layers per UE.
Codebook based mode means the precoding matrix can only be selected from known(predefined) cookbook.
Non-codebook based mode requests different demodulation/UE specific reference signals to be inserted in the allocated RBs of PDSCH before precoding and the precoding matrix is completely selected by randomly. This mode supports up to 8 transmission layers(ranks) per UE in Release10.
Closed-loop precoding is assumed that the network selects the precoder matrix based on feedback(CSI-PMI/RI) from the terminal.
Open-loop precoding does not rely on any detailed precoder recommendation being reported by the terminal and does not require any explicit network signaling of the actual precoder used for the downlink transmission. Instead, the precoder matrix is selected in a predefined and deterministic way known to the terminal in advance. One use of open-loop precoding is in high-mobility scenarios where accurate feedback is difficult to achieve due to the l******cy in the PMI reporting.

你问的应该是狭义的MIMO吧？也就是哪种模式能够达到单天线的双倍速率？如果你问的是这个含义，那么

TM3：开环空间复用
TM8：双流Beamforming（仅用于TDD）

其余的模式，对单用户来说，都只有1个layer，因此其理论速率是有限的

什么叫单天线双倍速？？双流必须多天线的好不好啊。TM4标准的空分复用不算？？

子森，你的理解能力可真糟糕啊！我哪里说双流用单天线了？我什么时候说单天线双倍速了？我明明说的是【哪种模式能够达到单天线的双倍速率】

目前国内的基站都是用TM3模式吗？有其他模式的吗？

请明白一点，LTE基站不会只用一种模式，而是会根据无线环境的不同而自动进行模式的变换，比如小区中心采用TM3/TM8，边缘采用TM2/TM7，具体要看各个厂家的实现

明白，谢谢

感谢

除了TM1之外，其他的都可以认为是MIMO。其中，TM3、TM4、TM8、TM9等是双流或多流。

在基站附近是TM3 基站覆盖边缘会变成TM8 极个别情况会出现TM2 TM3是RANK2 TM2、8都是RANK1

为何我在长沙做的单验 只有TM3是RANK2 其余都是RANK1呢

tm1和tm3速率有区别吗，或者区别多大！

谢谢大大分享