4G/LTE - Antenna Information at RRC  

Antenna Information at RRC Layer

At early stage of LTE deployment and for several years since then, I didn't care much of figuring out the number of antenna (Downlink Antenna) because all of the deployment (as far as I know) was 2 antenna system (2x2 MIMO or 2 x 1 Diversity). But recently I have been more and more curious of this since I am hearing various different antenna configurations lately (as of Feb 2017) like 4x2, 4x4 and even 8x2.

A question came to me : How a UE can figure out what kind of antenna (e.g, how many eNB antenna) configuration the eNB is using.

There are several different ways for eNB to tell UE of how many antenna it is using at a specific stage of communication. This page will list up those method of informing UE of antenna configuration. I don't think I need to put a lot of comments here. Just showing a specific part of RRC message would be enough.

Information on PBCH

Strictly speaking, this is not really at RRC Stage. This is lower than RRC layer. eNB can inform UE of how many antenna it is using by masking PBCH data (MIB data) based on following table. Refer to How to specify Antenna configuration in PBCH for the details.

< 36.212 Table 5.3.1.1-1 : CRC mask for PBCH >

Information on RRC Connection Reconfiguration / RRC Connection Setup - PCC

+-c1 ::= CHOICE [rrcConnectionReconfiguration-r8]

  +-rrcConnectionReconfiguration-r8 ::= SEQUENCE [001101]

    +-measConfig ::= SEQUENCE OPTIONAL:Omit

    +-mobilityControlInfo ::= SEQUENCE OPTIONAL:Omit

    +-dedicatedInfoNASList ::= SEQUENCE OF SIZE(1..maxDRB[11]) [1] OPTIONAL:Exist

    +-radioResourceConfigDedicated ::= SEQUENCE [110101] OPTIONAL:Exist

    | +-srb-ToAddModList ::= SEQUENCE OF SIZE(1..2) [1] OPTIONAL:Exist

    | +-drb-ToAddModList ::= SEQUENCE OF SIZE(1..maxDRB[11]) [1] OPTIONAL:Exist

    | +-drb-ToReleaseList ::= SEQUENCE OF OPTIONAL:Omit

    | +-mac-MainConfig ::= CHOICE [explicitValue] OPTIONAL:Exist

    | +-sps-Config ::= SEQUENCE OPTIONAL:Omit

    | +-physicalConfigDedicated ::= SEQUENCE [0100110010] OPTIONAL:Exist

    | | +-pdsch-ConfigDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-pucch-ConfigDedicated ::= SEQUENCE [0] OPTIONAL:Exist

    | | +-pusch-ConfigDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-uplinkPowerControlDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-tpc-PDCCH-ConfigPUCCH ::= CHOICE [setup] OPTIONAL:Exist

    | | +-tpc-PDCCH-ConfigPUSCH ::= CHOICE [setup] OPTIONAL:Exist

    | | +-cqi-ReportConfig ::= SEQUENCE OPTIONAL:Omit

    | | +-soundingRS-UL-ConfigDedicated ::= CHOICE OPTIONAL:Omit

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

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

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

    | | |   +-codebookSubsetRestriction ::= CHOICE [n4TxAntenna-tm3] OPTIONAL:Exist

    | | |   | +-n4TxAntenna-tm3 ::= BIT STRING SIZE(4) [1111]

    | | |   +-ue-TransmitAntennaSelection ::= CHOICE [release]

    | | +-schedulingRequestConfig ::= CHOICE OPTIONAL:Omit

    | | +-EXTENSION ::= SEQUENCE [0000100]

    | |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS2 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS5 ::= SEQUENCE [00001000] OPTIONAL:Exist

    | |   +-VERSION-BRACKETS6 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS7 ::= SEQUENCE OPTIONAL:Omit

    | +-EXTENSION ::= SEQUENCE [00000]

    |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS2 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS5 ::= SEQUENCE OPTIONAL:Omit

    +-securityConfigHO ::= SEQUENCE OPTIONAL:Omit

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

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

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

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

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

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

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

      |     +-nonCriticalExtension ::= SEQUENCE OPTIONAL:Omit

      +-nonCriticalExtension ::= SEQUENCE OPTIONAL:Omit

Information on RRC Connection Reconfiguration  - SCC

+-c1 ::= CHOICE [rrcConnectionReconfiguration-r8]

  +-rrcConnectionReconfiguration-r8 ::= SEQUENCE [000101]

    +-measConfig ::= SEQUENCE OPTIONAL:Omit

    +-mobilityControlInfo ::= SEQUENCE OPTIONAL:Omit

    +-dedicatedInfoNASList ::= SEQUENCE OF OPTIONAL:Omit

    +-radioResourceConfigDedicated ::= SEQUENCE [000001] OPTIONAL:Exist

    | +-srb-ToAddModList ::= SEQUENCE OF OPTIONAL:Omit

    | +-drb-ToAddModList ::= SEQUENCE OF OPTIONAL:Omit

    | +-drb-ToReleaseList ::= SEQUENCE OF OPTIONAL:Omit

    | +-mac-MainConfig ::= CHOICE OPTIONAL:Omit

    | +-sps-Config ::= SEQUENCE OPTIONAL:Omit

    | +-physicalConfigDedicated ::= SEQUENCE [0000000000] OPTIONAL:Exist

    | | +-pdsch-ConfigDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-pucch-ConfigDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-pusch-ConfigDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-uplinkPowerControlDedicated ::= SEQUENCE OPTIONAL:Omit

    | | +-tpc-PDCCH-ConfigPUCCH ::= CHOICE OPTIONAL:Omit

    | | +-tpc-PDCCH-ConfigPUSCH ::= CHOICE OPTIONAL:Omit

    | | +-cqi-ReportConfig ::= SEQUENCE OPTIONAL:Omit

    | | +-soundingRS-UL-ConfigDedicated ::= CHOICE OPTIONAL:Omit

    | | +-antennaInfo ::= CHOICE OPTIONAL:Omit

    | | +-schedulingRequestConfig ::= CHOICE OPTIONAL:Omit

    | | +-EXTENSION ::= SEQUENCE [0100000]

    | |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS5 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS6 ::= SEQUENCE OPTIONAL:Omit

    | |   +-VERSION-BRACKETS7 ::= SEQUENCE OPTIONAL:Omit

    | +-EXTENSION ::= SEQUENCE [00000]

    |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS2 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

    |   +-VERSION-BRACKETS5 ::= SEQUENCE OPTIONAL:Omit

    +-securityConfigHO ::= SEQUENCE OPTIONAL:Omit

    +-nonCriticalExtension ::= SEQUENCE [01] OPTIONAL:Exist

      +-lateNonCriticalExtension ::= OCTET STRING OPTIONAL:Omit

      +-nonCriticalExtension ::= SEQUENCE [001] OPTIONAL:Exist

        +-otherConfig-r9 ::= SEQUENCE OPTIONAL:Omit

        +-fullConfig-r9 ::= ENUMERATED OPTIONAL:Omit

        +-nonCriticalExtension ::= SEQUENCE [010] OPTIONAL:Exist

          +-sCellToReleaseList-r10 ::= SEQUENCE OF OPTIONAL:Omit

          +-sCellToAddModList-r10 ::= SEQUENCE OF SIZE(1..maxSCell-r10[4]) [1] OPTIONAL:Exist

          | +-SCellToAddMod-r10 ::= SEQUENCE [111]

          |   +-sCellIndex-r10 ::= INTEGER (1..7) [1]

          |   +-cellIdentification-r10 ::= SEQUENCE OPTIONAL:Exist

          |   | +-physCellId-r10 ::= INTEGER (0..503) [1]

          |   | +-dl-CarrierFreq-r10 ::= INTEGER (0..maxEARFCN[65535]) [1498]

          |   +-radioResourceConfigCommonSCell-r10 ::= SEQUENCE [0] OPTIONAL:Exist

          |   | +-nonUL-Configuration-r10 ::= SEQUENCE [00]

          |   | | +-dl-Bandwidth-r10 ::= ENUMERATED [n100]

          |   | | +-antennaInfoCommon-r10 ::= SEQUENCE

          |   | | | +-antennaPortsCount ::= ENUMERATED [an4]

          |   | | +-mbsfn-SubframeConfigList-r10 ::= SEQUENCE OF OPTIONAL:Omit

          |   | | +-phich-Config-r10 ::= SEQUENCE

          |   | | +-pdsch-ConfigCommon-r10 ::= SEQUENCE

          |   | | +-tdd-Config-r10 ::= SEQUENCE OPTIONAL:Omit

          |   | +-ul-Configuration-r10 ::= SEQUENCE OPTIONAL:Omit

          |   | +-EXTENSION ::= SEQUENCE [0000]

          |   |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

          |   |   +-VERSION-BRACKETS2 ::= SEQUENCE OPTIONAL:Omit

          |   |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

          |   |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

          |   +-radioResourceConfigDedicatedSCell-r10 ::= SEQUENCE [1] OPTIONAL:Exist

          |   | +-physicalConfigDedicatedSCell-r10 ::= SEQUENCE [10] OPTIONAL:Exist

          |   | | +-nonUL-Configuration-r10 ::= SEQUENCE [1001] OPTIONAL:Exist

          |   | | | +-antennaInfo-r10 ::= SEQUENCE [1] OPTIONAL:Exist

          |   | | | | +-transmissionMode-r10 ::= ENUMERATED [tm3]

          |   | | | | +-codebookSubsetRestriction-r10 ::= BIT STRING SIZE(ALIGNED) [1111]

          |   | | | | +-ue-TransmitAntennaSelection ::= CHOICE [release]

          |   | | | |   +-release ::= NULL

          |   | | | +-crossCarrierSchedulingConfig-r10 ::= SEQUENCE OPTIONAL:Omit

          |   | | | +-csi-RS-Config-r10 ::= SEQUENCE OPTIONAL:Omit

          |   | | | +-pdsch-ConfigDedicated-r10 ::= SEQUENCE OPTIONAL:Exist

          |   | | |   +-p-a ::= ENUMERATED [dB-6]

          |   | | +-ul-Configuration-r10 ::= SEQUENCE OPTIONAL:Omit

          |   | | +-EXTENSION ::= SEQUENCE [0100]

          |   | |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

          |   | |   +-VERSION-BRACKETS2 ::= SEQUENCE [00100] OPTIONAL:Exist

          |   | |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

          |   | |   +-VERSION-BRACKETS4 ::= SEQUENCE OPTIONAL:Omit

          |   | +-EXTENSION ::= SEQUENCE [000]

          |   |   +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

          |   |   +-VERSION-BRACKETS2 ::= SEQUENCE OPTIONAL:Omit

          |   |   +-VERSION-BRACKETS3 ::= SEQUENCE OPTIONAL:Omit

          |   +-EXTENSION ::= SEQUENCE [01]

          |     +-VERSION-BRACKETS1 ::= SEQUENCE OPTIONAL:Omit

          |     +-VERSION-BRACKETS2 ::= SEQUENCE [1] OPTIONAL:Exist

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

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

          +-nonCriticalExtension ::= SEQUENCE OPTIONAL:Omit