LTE: UE Capability Information

Direction: UE => E-UTRAN
Signalling Radio Bearer: SRB1
RLC Mode: AM
Logical Channel: DCCH
Transport Channel: UL-SCH

The UE CAPABILITY INFORMATION message is used to transfer of UE radio access capabilities requested by the E-UTRAN in UE CAPABILITY ENQUIRY.

ueCapabilityRAT-Container is the container for the UE capabilities of the indicated RAT. The encoding is defined in the specification of each RAT. For E-UTRA, the encoding of UE capabilities is defined in the IE UE-EUTRA-Capability which is explained below


Some important parameters in UE-EUTRA-Capability IE are given below:
accessStratumRelease: Set to Rel8, Rel9, Rel10 and so on (based on the UE’s  release)
maxNumberROHC-ContextSessions: Set to the maximum number of concurrently active ROHC contexts supported by the UE. cs2 corresponds with 2 (context sessions), cs4 corresponds with 4 and so on
ue-Category:  As per Rel10, the possible values are 1 to 8 (Ref: TS 36.306)
ue-TxAntennaSelectionSupported: TRUE indicates that the UE is capable of supporting UE transmit antenna selection as described in TS 36.213
halfDuplex: If halfDuplex is set to true, only half duplex operation is supported for the band, otherwise full duplex operation is supported. This entry is present in each of the supported bands
bandListEUTRA: One entry corresponding to each supported E-UTRA band listed in the same order as in supportedBandListEUTRA
interFreqBandList: One entry corresponding to each supported E-UTRA band listed in the same order as in supportedBandListEUTRA
interFreqNeedForGaps: Indicates need for measurement gaps when operating on the E-UTRA band given by the entry in bandListEUTRA and measuring on the E-UTRA band given by the entry in interFreqBandList
interRAT-BandList: One entry corresponding to each supported band of another RAT listed in the same order as in the interRAT-Parameters
interRAT-NeedForGaps: Indicates need for DL measurement gaps when operating on the E-UTRA band given by the entry in bandListEUTRA and measuring on the inter-RAT band given by the entry in the interRAT-BandList
SupportedBandUTRA-FDD: UTRA band as defined in TS 25.101
SupportedBandGERAN: GERAN band as defined in TS 45.005

featureGroupIndicators, featureGroupIndRel9Add, featureGroupIndRel10: These featureGroupIndicators IE is a bit string, where each bit indicate support for a specific feature. The definitions of the bits in the bit string are described in Annex B.1 (for featureGroupIndicators and featureGroupIndRel9Add) and in Annex C.1.(for featureGroupIndRel10) of 36.331


Example: UE CAPABILITY INFORMATION










Reference: 3GPP TS 36.331

16 comments:

  1. how can you tell in the "UE Capability Information" that a feature efficient DRX/DTX for capable UE is actually sending this message??

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    Replies
    1. As per the 3gpp, the only reference to DRX is in section "4.2 UE Capability Parameters", and under "4.2.6 MAC parameters" you'll find:
      - longDRX-Cycle: Indicates whether UE supports long DRX cycle as specified in TS 38.321 [8].
      - shortDRX-Cycle: Indicates whether UE supports short DRX cycle as specified in TS 38.321 [8].

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  2. how to decode ueCapabilityRAT-Container=?

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    Replies
    1. Try this decoder: https://www.3glteinfo.com/3gpp-decoder/

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  3. What is the maximum size of UE Capability Information in octets to be supported in the specification?

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    Replies
    1. As per 3GPP 36.323 , Its 8188 octet

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    2. RRC message or PDCP size? Would they be different?

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  4. From which field of the "UE Capability Information" can we know what 3GPP Release is supported by the UE?

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    Replies
    1. Nothing like that is shared by the UE in the UE Capability Information.

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    2. I correct myself, this is what I wanted to say: Nothing like that is shared by the UE in the UE Capability container, but it is mentioned just in the field above the container. Here is an example:
      "ueCapabilityInformation": {
      "rrc-TransactionIdentifier": 0,
      "criticalExtensions": {
      "c1": {
      "ueCapabilityInformation-r8": {
      "ue-CapabilityRAT-ContainerList": [
      {
      "rat-Type": "eutra",
      "ueCapabilityRAT-Container":HEX CODE IS HERE

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  5. Did you get information of decoding this container? Please suggest if you have this info.

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    Replies
    1. Try this decoder: https://www.3glteinfo.com/3gpp-decoder/

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  6. Is UE Capability in Idle or Connected Mode?

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    Replies
    1. UE Capability Information is sent from the UE to the EUTRAN, while moving from Idle to Connected Mode.

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  7. in the UECapabilityInformation msg, we can see :

    1. release of 3GPP supported by the UE
    2. check also the category of the UE, Cat14, cat16, or cat20
    3. can also check the supported band
    4.can also check supported RAN features like CA, how many CA cells ....

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  8. Can anyone tell about ue cap type?

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