categoryue协议_LTE中UE能⼒（UECapability）的梳理和解
析
1. 关于LTE中UE能⼒的问题，也是⼤家经常提问的地⽅之⼀。 ⽐如” UE⽀持的RAT？ / UE⽀持的Frequecy band ？ / UE的功率等级？ / UE是否⽀持CA，且是那种类型的CA？ / UE是否⽀持PS HO ？ / UE是否⽀持SRVCC？ / 现在系统间移动性⼤多采⽤Redirect⽽不是PS HO, 是UE能⼒不⽀持么？ / UE⽀持哪些安全算法(加密/完保)？”…… 等等，这些问题都牵扯到UE能⼒。 所以今天春天⼯作室试图对其进⾏梳理和解析。
2. UE能⼒可分为⽆线接⼊相关能⼒及核⼼⽹相关能⼒。The UE Capability information is made up of the UE Radio Capabilityinformationand the UE Core Network Capability information。 涉及到UE能⼒的规范⽐较多，这⾥先列出规范号，分别是36.101/36.306/2
3.401/36.331/2
银杏的功效4.008。
3. ⽹络侧在做各种事件判决或执⾏各种算法时，均需知道UE的能⼒，才能做出最切合的判决。⽐如，UE如果⽀持CSFB发起联合附着，那么此时⽹络侧对其执⾏和处理的过程会不⼀样； 如果UE不⽀持PS
HO的inter-RAT的mobility时， 那么⽹络也只能采取NACC/CCO或者Redirct来实现系统间互操作了；所以，由于UE的能⼒各不相同且差异较⼤，那么⽹络需要获知UE的能⼒。 这就要求UE能⼒可以通过某种⽅式上报并同步了。
4. UE的能⼒上报及同步，是UE第⼀次ATTACH或TAU的时候，UE会主动上报⾃⼰的能⼒，此属于NAS过程； ⽽⽆线侧在RRC规范中，也有UE能⼒查询过程，获取并传递UE能⼒。
见得5. 下⾯贴图是⼀次完成的attach的过程。我们可以把UE能⼒查询及上报的过程，放在整个信令流程中去理解。
参考上图，如果消息9中，携带了UE Radio Capability 的IE，则eNB不会发送UECapabilityEnquiry消息给UE，即没有10/11/12的过程； 否则，如果消息9中没有携带UE能⼒，则基站会发起UE能⼒查询过程，这在第⼀次⼊⽹(ATTACH/TAU)的过程中经常会看到。⽽UE 上报了⽆线能⼒信息到eNB之后，eNB再给MME发送Capability Info Indication消息，传递并上报UE的能⼒信息⾄MME。
⽽在协议设计中，为了减少空⼝信令开销，MME会保存UE Radio Capability信息，⽽在S1流程INITIAL CONTEXT SETUP REQUEST消息中，MME还会把UE能⼒传递给eNB，故此时eNB⽆需针对UE发起UECapabilityEnquiry过程，因为UE能⼒可知。
立项文件但是，在UE在执⾏attach或者“first TAU following GERAN/UTRANAttach” 或“UE radio capability update”时， MME不会在INITIAL CONTEXT SETUP REQUEST消息中带UE Radio Capability信息给eNB的， 并会把本地保存的UE Radio Capability信息删除，故这三种情况，eNB会问UE要UE能⼒，在eNB获知之后还需上报给MME。
注：'UEradio capability update' TAU is only supported for changes of GERAN and UTRAN radio capabilities in ECM-IDLE。
这⾥⾯有2个推论： 1. 在RRC-CONNECTED下，eNB也会⼀直保存UE Radio Capability信息。反过来，UE从RRC连接态转移到RRC空闲态下，UE的RRC连接的上下⽂会释放，⾃然eNB针对某个UE的能⼒信息也将删除。但此时MME不会删除UE的能⼒信息的，因为MME 依然是MM-REGISTERED，除⾮UE去附着(detach)或其他。 2. UE⽆线能⼒信息如果发⽣改变，UE需要先发起detach，再attach。 ⼀个很简单的例⼦，⽐如我们把CMCC的5模⼿机现在锁死在LTE单模下⼯作，相当于⼈为的改变了UE的能⼒，此时我们会发现UE的信号图标，会暗了，再亮了。 如果去跟信令的话，这就会是⼀次“UE能⼒改变”导致的“去附着 附着“ 的过程。这样去附着 附着机制，保证了UE能⼒信息的同步。
进⼀步说，在附着过程中，与UE能⼒相关的信令，会有2个 ——NAS EMM信令 ATTACH REQUEST 及 RRC信令UE Capability Enquiry / Information。之前的贴图中已经标注。
可以看出，在Attach request中，UE会将⾃⼰的安全能⼒(⽀持的EEA/EIA算法)上报， 其⽬的是协商UE和MME之间的NAS安全性，并对随后的NAS信令交互进⾏加密和完整性保护。 另外注意到，除了UE network capability之外， UE还会上报跟23G相关的MS Radio Access capability，后者对现在234G共存的情况下变得重要。截图如下：
6. RRC过程中与UE能⼒相关的主要是UECapabilityEnquiry及UECapabilityInformation。其中最丰富的是UECapabilityInformation，规范中的截图如下：
截图限于篇幅并没有完整的截完，具体参考TS36.331等规范。这⾥对某些IE做简要解释：
accessStratumRelea：接⼊版本，其实就是3GPP版本，⽐如R9、R10。
ue-Category：就是我们通常所说的⼿机种类。见下截图，其中蓝字部分为Relea8中定义的内容，绿字部分为Relea10定义的内容。UE Category 有时也被称作 UE Class。eNodeB和UE之间需⽤通过UE Category来确定UE的传输能⼒。
pdcp-Parameters：UE⽀持的ROHC头压缩算法的能⼒情况。
rf-Parameters：UE射频能⼒，表⽰UE能够⽀持的band。
FGI(Feature group indicators)：这项⾮常重要但也⽐较繁琐，显⽰了UE的各种实际能⼒，不同的能⼒的⽀持，在⽹络中就会有不同体现。 eNB也会根据这些能⼒做不同判断。 ⽽在36.331附录B1中，对FGI的各个bit所对应的能⼒做了完整的定义，置1表⽰⽀持，置0表⽰不⽀持，感兴趣的请参考。
interRAT-Parameters：UE对于异系统的⽀持能⼒，这是eNB判决UE能否进⾏互操作的重要依据。
在R10中引⼊了CA载波聚合，故⽀持CA的UE需要在接⼊的时候上报其CA的⽀持情况，其中会有ca-BandwidthClassDL-r10 ca-BandwidthClassUL-r10等IE，见前⾯的截图。给的拼音
⽐如，如果ca-BandwidthClassDL-r10 为a类别，就说明UE下⾏只⽀持1个载波； 如果ca-BandwidthClassDL-r10 为c类别，就说明UE 下⾏⽀持2个CC的载波聚合。 Class A: aggregated transmitted BW configuration <= 100PRBs and 1 component carrier。 Class C: aggregated transmitted BWconfiguration of 101 to 200 PRBs and 2 component carriers。
关于CA的类别，见后⾯的截图。
附录1：23401中关于UE能⼒处理过程的描述
5.11 UE Capability Handling
5.11.1 General
The UE Capability information is made up of the UE Radio Capabilityinformation and the UE Core Network Capabilityinformation.
5.11.2 UE Radio Capability Handling
The UE Radio Capability information contains information on RATsthat the UE supports (e.g. power class, frequency bands, etc). Conquently,this information can be sufficiently large (e.g. >50 octets) that it isundesirable to nd it across the radio interface at every transition from ECM?IDLEto ECM?CONNECTED. To avoidthis radio overhead, the MME stores the UE Capability information during ECM?IDLEstate and the MME shall, if it is available, nd its most up to date UE RadioCapability information to the E?UTRAN in the S1 interface INITIAL CONTEXT SETUPREQUEST message unless the UE is performing an Attach procedure or a TrackingArea Update procedure for the 'first TAU following GERAN/UTRANAttach' orfor a 'UE radio capabilityupdate'.
NOTE 1: Fora GERAN/UTRAN/E-UTRAN capable UE, this UE Radio Capability information isbroadly equivalent to the combination of the MS Radio Access capability nt in theTS 24.008 [47] Attach Request message plus the Inter RAT Handoverinformation nt in the TS 24.008 [47] Attach Complete message.
If the UE is performing an Attach procedureor a Tracking Area Update procedure for the 'first TAU followingGERAN/UTRAN Attach' or for 'UE radio capability update', the MMEshall delete (or mark as deleted) any UE Radio Capability information that ithas stored, and, if the MME nds an S1 interface INITIAL CONTEXT SETUP REQUESTmessage during that procedure, the MME shall not nd any UE Radio Capabilityinformation to the E?UTRAN in that message. This triggers the E?UTRAN torequest the UE Radio Capability from the UE and upload it to the MME in the S1interface UE CAPABILITY INFO INDICATION message.
If the UE is performing a Service Request(or other) procedure and the MME does not have UE Radio Capability informationavailable (or it is available, but marked as 'deleted'), then the MMEnds an S1 interface INITIAL CONTEXT SETUP REQUEST message to the E?UTRANwithout any UE Radio Capability information in it. This triggers the E?UTRAN torequest the UE Radio Capability from the UE and upload it to the MME in the S1interface UE CAPABILITY INFO INDICATION message.
雨字笔画NOTE 2: Thisu of the INITIAL CONTEXT SETUP REQUEST message means that for a signallingonly procedure such as a periodic Tracking Area Update, the UE Radio Capability would not be nt to the E?UTRAN.
NOTE 3: If a 'first TAU following GERAN/UTRAN Attach' Tracking Area Update isperformed during ECM-CONNECTED mode, e.g. after an inter RAT handover, noINITIAL CONTEXT SETUP REQUEST is nt and the UE Radio Capability informationin the MME will remain deleted until the next ECM-IDLE to ECM-CONNECTEDtransition (or later, e.g. if the next activity from the UE is another TrackingArea Update).
The UE Radio Capability is not provided directly from one CN node toanother. It will be uploaded to the MME when the E-UTRAN requests the UE RadioCapability information from the UE.
During handover via the MME (both intra RAT and inter RAT), the UERadio Capability is transferred in the 'source to target transparent container'.Even in the ca of handover from a different RAT, this UE Radio Capabilityshould be the full radio capability information for all of the 3GPP RATs thatthat UE supports.
NOTE 4: For example in the ca of a GERAN/UTRAN/E-UTRAN capable UE being handed over fromGERAN to E-UTRAN, the 'source to target transparent container' wouldcarry UTRAN, GERAN and E-UTRAN radio access capabilities. This is necessary toenable subquent handovers to a different (and/or the original) RAT.
To allow for the addition of future radio technologies, frequencybands, and other enhancements, the MME shall store the UE Radio CapabilityInformation even if it is larger than specified in TS 36.331 [37], upto a maximum size of 510 octets.
NOTE 5: The510 octet value comes from the information element encoding rulesdescribed in TS 24.007 [45] and the assumption that the informationcontained within this UE Radio Capability Information Element stored by the MMEis the equivalent of information signalled in two information elements in theGERAN NAS signalling for the ca of GERAN to E? UTRAN PS handover.
The E?UTRAN stores the UE Radio Capability information, received inthe S1 interface INITIAL CONTEXT SETUP REQUEST message or obtained from the UE,for the duration of the RRC connection for that UE.
If the UE's UE Radio Capability information changes while inECM-IDLE state (including cas of being in GERAN/UTRAN coverage), the UE shallperform a Tracking Area Update indicating 'UE radio capabilityupdate' when it next returns to E? UTRAN coverage.
NOTE 6: Inthis relea of the specifications, 'UE radio capability update' isonly supported for changes of GERAN and UTRAN radio capabilities in ECM-IDLE.Any change in the UE's E?UTRAN
capabilities requires the UE to detach and thenre-attach to the system.
5.11.3 UE Core Network Capability
The UE Core Network Capability is splitinto the UE Network Capability IE (mostly for E-UTRAN access related corenetwork parameters) and the MS Network Capability IE (mostly for UTRAN/GERAN accessrelated core network parameters) and contains non radio-related the NAS curity algorithms etc. Both the UE Network Capability and the MSNetwork Capability are transferred between CN nodes at MME to MME, MME to SGSN,SGSN to SGSN, and SGSN to MME changes. (……)
附录2：36331中关于UE能⼒中的FGI的定义
B.1 Feature group indicators
This annex contains the definitions of thebits in field featureGroupIndicators.
In this relea of the protocol, the UE shall include the fieldfeature Group Indicators in the IE UE-EUTRA-Capability. All the functionalities defined within the field feature Group Indicators defined in Table B.1-1 are mandatory for the UE, if the related capability (frequency band, RAT or SR-VCC) is a
lso supported. For a specific indicator, if all functionalities for a feature group listed in Table B.1-1 have been implemented and tested, the UE shall t theindicator as one (1), el (i.e. if any one of the functionalities in a featuregroup listed in Table B.1-1, which have not been implemented or tested), the UE shall t the indicator as zero (0).
The UE shall t all indicators that correspond to RATs not supported by the UE as zero (0).
The UE shall t all indicators, which do not have a definition in Table B.1-1, as zero (0).
If the optional field featureGroupIndicators is not included by a UE of a future relea,the network may assume that all features pertaining to the RATs supported bythe UE, listed in Table B.1-1 and deployed in the network, have beenimplemented and tested by the UE.我懂得了
In Table B.1-1, a 'VoLTE capable UE'corresponds to a UE that is capable of the 'Voice domain preference for E-UTRAN' defined in TS 24.301 [35] being t to 'IMS PS voiceonly', 'IMS PS voice preferred, CS voice as condary' or 'CS voice preferred, IMS PS voice as condary'.
Table B.1-1: Definitions of feature groupindicatorsIndex of indicator (bit number)Definition
(description of the supported functionality, if indicator t to one)NotesIf indicated 'Yes' the feature s
hall be implemented and successfully tested for this version of the specification
1 (leftmost bit)- Intra-subframe frequency hopping for PUSCH scheduled by UL grant
- DCI format 3a (TPC commands for PUCCH and PUSCH with single bit power adjustments)
- PDSCH transmission mode 5
怎样推迟绝经期
- Aperiodic CQI/PMI/RI reporting on PUSCH: Mode 2-0 – UE lected subband CQI without PMI
- Aperiodic CQI/PMI/RI reporting on PUSCH: Mode 2-2 – UE lected subband CQI with multiple PMI
2- Simultaneous CQI and ACK/NACK on PUCCH, i.e. PUCCH format 2a and 2b
- Absolute TPC command for PUSCH
- Resource allocation type 1 for PDSCH
- Periodic CQI/PMI/RI reporting on PUCCH: Mode 2-0 – UE lected subband CQI without PMI
- Periodic CQI/PMI/RI reporting on PUCCH: Mode 2-1 – UE lected subband CQI with single PMI
3- 5bit RLC UM SN
- 7bit PDCP SN- can only be t to 1 if the UE has t bit number 7 to 1.Yes, if UE supports VoLTE
4- Short DRX cycle- can only be t to 1 if the UE has t bit number 5 to 1.
5- Long DRX cycle
- DRX command MAC control elementYes
6- Prioritid bit rateYes
7- RLC UM- can only be t to 0 if the UE does not support VoLTEYes, if UE supports VoLTE
8- EUTRA RRC_CONNECTED to UTRA CELL_DCH PS handover- can only be t to 1 if the UE has t bit number 22 to 1Yes, if UE supports UTRA
9- EUTRA RRC_CONNECTED to GERAN GSM_Dedicated handover- related to SR-VCC
- can only be t to 1 if the UE has t bit number 23 to 1
10- EUTRA RRC_CONNECTED to GERAN (Packet_) Idle by Cell Change Order
- EUTRA RRC_CONNECTED to GERAN (Packet_) Idle by Cell Change Order with NACC (Network Assisted Cell Change)
11- EUTRA RRC_CONNECTED to CDMA2000 1xRTT CS Active handover- related to SR-VCC
- can only be t to 1 if the UE has ts bit number 24 to 1
12- EUTRA RRC_CONNECTED to CDMA2000 HRPD Active handover- can only be t to 1 if the UE has t bit number 26 to 1
13- Inter-frequency handover- can only be t to 1 if the UE has t bit number 25 to 1Yes, unless UE only supports band 13
14- Measurement reporting event: Event A4 – Neighbour > threshold
- Measurement reporting event: Event A5 – Serving < threshold1 & Neighbour > threshold2
15- Measurement reporting event: Event B1 – Neighbour > threshold- can only be t to 1 if the UE has t at least one of the bit number 22, 23, 24 or 26 to 1.
16- non-ANR related intra-frequency periodical measurement reporting;
- non-ANR related inter-frequency periodical measurement reporting, if the UE has t bit number 25 to 1; and
- non-ANR related inter-RAT periodical measurement reporting for UTRAN, GERAN, 1xRTT or HRPD, if the UE has t bit number 22, 23, 24 or 26 to 1, respectively.
NOTE: “non-ANR related periodical measurement reporting” corresponds only to ‘periodical’ trigger type with purpo t to ‘reportStrongestCells’. Event triggered periodical reporting (i.e., ‘event’ trigger type with reportAmount > 1) is a mandatory functionality of event triggered reporting and therefore not the subject of this bit.Yes
17- Periodical measurement reporting for SON / ANR
- ANR related intra-frequency measurement reporting events- can only be t to 1 if the UE has t bit number 5 to 1.Yes
18- ANR related inter-frequency measurement reporting events- can only be t to 1 if the UE has t bit number 5 to
1.Yes, unless UE only supports band 13
19- ANR related inter-RAT measurement reporting events- can only be t to 1 if the UE has t bit number 5 to 1.
20If bit number 7 is t to ‘0’:
- SRB1 and SRB2 for DCCH 8x AM DRB
If bit number 7 is t to ‘1’:
- SRB1 and SRB2 for DCCH 8x AM DRB
- SRB1 and SRB2 for DCCH 5x AM DRB 3x UM DRB
NOTE: UE which indicate support for a DRB combination also support all subts of the DRB combination. Therefore,
女性用品推荐relea of DRB(s) never results in an unsupported DRB combination.- Regardless of what bit number 7 and bit number 20 is t to, UE shall support at least SRB1 and SRB2 for DCCH 4x AM DRB
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Regardless of what bit number 20 is t to, if bit number 7 is t to ‘1’, UE shall support at least SRB1 and SRB2 for
DCCH 4x AM DRB 1x UM DRBYes
21- Predefined intra- and inter-subframe frequency hopping for PUSCH with N_sb > 1
- Predefined inter-subframe frequency hopping for PUSCH with N_sb > 1
22- UTRAN measurements, reporting and measurement reporting event B2 in E-UTRA connected modeYes, if UE supports UTRA
