在LTE发展初期，大部分终端都是CAT3和4；网络和终端侧都支持2*2 MIMO;2017年后2天线已经成为基本配置，以下已成为现网标准配置：整理：kangguoying20200710

•         2x2

•         4x2

•         4x4

•         8x2

整理：kangguoying20200710

        针对这些配置，网络需了解UE的天线能力；而UE不需要了解网络侧，因为UE可应用任何网络的要求，由网络计算出UE的能力，为其进行MIMO配置;另一种方法，也就是UE可以计算出网络侧的天线配置；整理：kangguoying20200710

 1.终端对eNB的MIMO识别

        终端通过对“PBCH CRC Mask”检测获得eNB使用的天线数量，但不能获得eNB在发送“RRC连接建立和重配置”时使用的MIMO方式；整理：kangguoying20200710

 2.网络对UE的MIMO能力识别

        网络通过UE”Capability”字节获得其MIMO能力；该字段是网络向UE进行能力查询时UE”Capability”自其上报告的信息中获得；在UE能力表中，我们可以找出其支持的layer数，通过这些信息网络可以直接查到UE的MIMO能力；如果UE的能力支持layer2，则终端支持2*2和4*2的MIMO模式；如果支持layer 4，则UE支持4x4的MIMO模式;

整理：kangguoying20200710

3.实例整理：kangguoying20200710

3.1   2x2 TM3

| | +-antennaInfo ::= CHOICE [explicitValue] OPTIONAL:Exist

  | | | +-explicitValue ::= SEQUENCE [1]整理：kangguoying20200710

  | | |   +-transmissionMode ::= ENUMERATED [tm3]整理：kangguoying20200710

  | | |   +-codebookSubsetRestriction ::= CHOICE [n2TxAntenna-tm4] OPTIONAL:Exist

  | | |   | +-n2TxAntenna-tm3 ::= BIT STRING SIZE(2) [111111整理：kangguoying20200710

3.2 2x2 TM4

| | +-antennaInfo ::= CHOICE [explicitValue] OPTIONAL:Exist

  | | | +-explicitValue ::= SEQUENCE [1]整理：kangguoying20200710

  | | |   +-transmissionMode ::= ENUMERATED [tm4]整理：kangguoying20200710

  | | |   +-codebookSubsetRestriction ::= CHOICE [n2TxAntenna-tm4] OPTIONAL:Exist

  | | |   | +-n2TxAntenna-tm4 ::= BIT STRING SIZE(2) [111111整理：kangguoying20200710

3.3 4x2 TM3

 | | +-antennaInfo ::= CHOICE [explicitValue] OPTIONAL:Exist

  | | | +-explicitValue ::= SEQUENCE [1]整理：kangguoying20200710

  | | |   +-transmissionMode ::= ENUMERATED [tm3]整理：kangguoying20200710

  | | |   +-codebookSubsetRestriction ::= CHOICE [n4TxAntenna-tm4] OPTIONAL:Exist

  | | |   | +-n4TxAntenna-tm3 ::= BIT STRING SIZE(64)整理：kangguoying20200710

                              [1111111111111111111111111111111111111111111111111111111111111111]

3.4 4x4 TM3

 | | +-antennaInfo ::= CHOICE [explicitValue] OPTIONAL:Exist

  | | | +-explicitValue ::= SEQUENCE [1]整理：kangguoying20200710

  | | |   +-transmissionMode ::= ENUMERATED [tm3]整理：kangguoying20200710

  | | |   +-codebookSubsetRestriction ::= CHOICE [n4TxAntenna-tm4] OPTIONAL:Exist

  | | |   | +-n4TxAntenna-tm3 ::= BIT STRING SIZE(64)整理：kangguoying20200710

                              [1111111111111111111111111111111111111111111111111111111111111111]

 +-nonCriticalExtension ::= SEQUENCE [10] OPTIONAL:Exist整理：kangguoying20200710

    +-lateNonCriticalExtension ::= OCTET STRING CONSTRAINTED [0000000101101010] OPTIONAL:Exist

    | +-RRCConnectionReconfiguration-v8m0-IEs ::= SEQUENCE [01]整理：kangguoying20200710

    |   +-lateNonCriticalExtension ::= OCTET STRING OPTIONAL:Omit

    |   +-nonCriticalExtension ::= SEQUENCE [10] OPTIONAL:Exist整理：kangguoying20200710

    |     +-antennaInfoDedicatedPCell-v10i0 ::= SEQUENCE [1] OPTIONAL:Exist

    |     | +-maxLayersMIMO-r10 ::= ENUMERATED [fourLayers] OPTIONAL:Exist

    |     +-nonCriticalExtension ::= SEQUENCE OPTIONAL:Omit整理：kangguoying20200710

原文来自：http://www.sharetechnote.com/整理：kangguoying20200710