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4G/LTE - LTE Advanced |
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UE Category for PHY layer throughput
UE Category is the set of information (parameters) that defines the maximum throughput for a UE. As LTE evolves, the length of UE category list gets longer and longer, and the interpretation of the category gets more complicated, you will need to go through many tables listed below to figure out the exact throughput capability of a UE. Followings are the list of tables you would need to go through for the detailed understanding.
RRC Message (UE Capability Information) that defines UE Category
The category that UE support is indicated in UE Capability Information message as shown below. Notice that ue-Category can specify only up to Cat 4. The category higher than 4 should be assinged to another IE (Information Element) ue-Category-v1020. (Here we are having similar confusing IEs as in WCDMA/HSPA. So many different places to check to figure out exact category)
Example 1 >
ueCapabilityInformation-r8 ue-CapabilityRAT-ContainerList: 1 item Item 0 UE-CapabilityRAT-Container rat-Type: eutra (0) ueCapabilityRAT-Container: .... UE-EUTRA-Capability accessStratumRelease: rel11 (3) ue-Category: 4 ... phyLayerParameters .... 0... ue-TxAntennaSelectionSupported: False .... .0.. ue-SpecificRefSigsSupported: False rf-Parameters supportedBandListEUTRA: 15 items... measParameters bandListEUTRA: 15 items ... featureGroupIndicators: ... ... interRAT-Parameters ... nonCriticalExtension phyLayerParameters-v920 ... interRAT-ParametersGERAN-v920 ... interRAT-ParametersUTRA-v920 ... csg-ProximityIndicationParameters-r9 neighCellSI-AcquisitionParameters-r9 ... son-Parameters-r9 ... nonCriticalExtension lateNonCriticalExtension:... UE-EUTRA-Capability-v9a0-IEs featureGroupIndRel9Add-r9: ... ... fdd-Add-UE-EUTRA-Capabilities-r9 phyLayerParameters-r9 ... featureGroupIndicators-r9: ... ... featureGroupIndRel9Add-r9: ... ... tdd-Add-UE-EUTRA-Capabilities-r9 phyLayerParameters-r9 ... featureGroupIndicators-r9: ... ... featureGroupIndRel9Add-r9: ... ... nonCriticalExtension ue-Category-v1020: 6 phyLayerParameters-v1020 multiClusterPUSCH-WithinCC-r10: supported (0) nonContiguousUL-RA-WithinCC-List-r10: ... ... rf-Parameters-v1020 supportedBandCombination-r10: ... ... measParameters-v1020 bandCombinationListEUTRA-r10: ... ... featureGroupIndRel10-r10: ... ... ue-BasedNetwPerfMeasParameters-r10 ... nonCriticalExtension fdd-Add-UE-EUTRA-Capabilities-v1060 featureGroupIndRel10-v1060: ... ... tdd-Add-UE-EUTRA-Capabilities-v1060 featureGroupIndRel10-v1060: ... ... rf-Parameters-v1060 supportedBandCombinationExt-r10: ... ... nonCriticalExtension nonCriticalExtension pdcp-Parameters-v1130 phyLayerParameters-v1130 crs-InterfHandl-r11: supported (0) tdd-SpecialSubframe-r11: supported (0) rf-Parameters-v1130 supportedBandCombination-v1130: ... ... measParameters-v1130 interRAT-ParametersCDMA2000-v1130 otherParameters-r11 nonCriticalExtension ue-Category-v1170: 9 nonCriticalExtension
Example 2 >
UE-EUTRA-Capability ::= SEQUENCE [11] +-accessStratumRelease ::= ENUMERATED [rel11] +-ue-Category ::= INTEGER (1..5) [4] +-pdcp-Parameters ::= SEQUENCE [0] +-phyLayerParameters ::= SEQUENCE +-rf-Parameters ::= SEQUENCE +-measParameters ::= SEQUENCE +-featureGroupIndicators ::= BIT STRING SIZE(32) OPTIONAL:Exist +-interRAT-Parameters ::= SEQUENCE [0000000] +-nonCriticalExtension ::= SEQUENCE [0001] OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE [11] OPTIONAL:Exist +-lateNonCriticalExtension ::= OCTET STRING CONSTRAINTED +-nonCriticalExtension ::= SEQUENCE [111110101] OPTIONAL:Exist +-ue-Category-v1020 ::= INTEGER (6..8) [7] OPTIONAL:Exist +-phyLayerParameters-v1020 ::= SEQUENCE [0000011] OPTIONAL:Exist +-rf-Parameters-v1020 ::= SEQUENCE OPTIONAL:Exist +-measParameters-v1020 ::= SEQUENCE OPTIONAL:Exist +-featureGroupIndRel10-r10 ::= BIT STRING SIZE(32) +-interRAT-ParametersCDMA2000-v1020 ::= SEQUENCE OPTIONAL:Omit +-ue-BasedNetwPerfMeasParameters-r10 ::= SEQUENCE [11] OPTIONAL:Exist +-interRAT-ParametersUTRA-TDD-v1020 ::= SEQUENCE OPTIONAL:Omit +-nonCriticalExtension ::= SEQUENCE [0011] OPTIONAL:Exist +-fdd-Add-UE-EUTRA-Capabilities-v1060 ::= SEQUENCE OPTIONAL:Omit +-tdd-Add-UE-EUTRA-Capabilities-v1060 ::= SEQUENCE OPTIONAL:Omit +-rf-Parameters-v1060 ::= SEQUENCE OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE [01] OPTIONAL:Exist +-rf-Parameters-v1090 ::= SEQUENCE OPTIONAL:Omit +-nonCriticalExtension ::= SEQUENCE [1001] OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE [011] OPTIONAL:Exist +-phyLayerParameters-v1170 ::= SEQUENCE OPTIONAL:Omit +-ue-Category-v1170 ::= INTEGER (9..10) [10] OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE [10001] OPTIONAL:Exist +-rf-Parameters-v1180 ::= SEQUENCE [100] OPTIONAL:Exist +-mbms-Parameters-r11 ::= SEQUENCE OPTIONAL:Omit +-fdd-Add-UE-EUTRA-Capabilities-v1180 ::= SEQUENCE OPTIONAL:Omit +-tdd-Add-UE-EUTRA-Capabilities-v1180 ::= SEQUENCE OPTIONAL:Omit +-nonCriticalExtension ::= SEQUENCE [101] OPTIONAL:Exist +-ue-Category-v11a0 ::= INTEGER (11..12) [12] OPTIONAL:Exist +-measParameters-v11a0 ::= SEQUENCE OPTIONAL:Omit +-nonCriticalExtension ::= SEQUENCE [010011000000001] OPTIONAL:Exist +-phyLayerParameters-v1250 ::= SEQUENCE OPTIONAL:Omit +-rf-Parameters-v1250 ::= SEQUENCE [1000] OPTIONAL:Exist +-rlc-Parameters-r12 ::= SEQUENCE OPTIONAL:Omit +-ue-BasedNetwPerfMeasParameters-v1250 ::= SEQUENCE OPTIONAL:Omit +-ue-CategoryDL-r12 ::= INTEGER (0..14) [12] OPTIONAL:Exist +-ue-CategoryUL-r12 ::= INTEGER (0..13) [13] OPTIONAL:Exist +-wlan-IW-Parameters-r12 ::= SEQUENCE OPTIONAL:Omit +-measParameters-v1250 ::= SEQUENCE OPTIONAL:Omit +-dc-Parameters-r12 ::= SEQUENCE OPTIONAL:Omit +-mbms-Parameters-v1250 ::= SEQUENCE OPTIONAL:Omit +-mac-Parameters-r12 ::= SEQUENCE OPTIONAL:Omit +-fdd-Add-UE-EUTRA-Capabilities-v1250 ::= SEQUENCE OPTIONAL:Omit +-tdd-Add-UE-EUTRA-Capabilities-v1250 ::= SEQUENCE OPTIONAL:Omit +-sl-Parameters-r12 ::= SEQUENCE OPTIONAL:Omit +-nonCriticalExtension ::= SEQUENCE [11] OPTIONAL:Exist +-ue-CategoryDL-v1260 ::= INTEGER (15..16) [16] OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE [10] OPTIONAL:Exist +-rf-Parameters-v1270 ::= SEQUENCE [10] OPTIONAL:Exist +-nonCriticalExtension ::= SEQUENCE OPTIONAL:Omit
36.306 defines the maximum throughput for each category as follows :
Note : Following throughput does not make difference about the number of Carriers. When you are talking about Categories about Carrier Aggregation throughput, you would be clear on whether you are talking about the category for each component carrier or categories of aggregated carriers. This tables tells you only about the maximum throughput, it doesn't tell in detail about how you achieve it. Many people tries to associate this table to a specific MIMO configuration or Carrier Aggregation(CA) configuration. But there is no direction connection between this table and MIMO/CA condition.
< 36.306 v12.6 Table 4.1-1: Downlink physical layer parameter values set by the field ue-Category >
< 36.306 v12.6 Table 4.1-2: Uplink physical layer parameter values set by the field ue-Category >
Note 1 : The number shown in this table is the number of bits that can be transmitted in 1 TTI (1 ms). So you have to multiply this number by 1000 to get the rate in 'bps'. For example, Table 4.1-1 Category 3 says 102048. If you convert this number into bps, it is 102048 x 1000 = 102,048,000 bps.
Note 2 : You should be very careful when you talk about the throughput in Kbps, Mbps unit. A lot of people do the conversion by dividing the number by 1000, 1000000. But in digital theory (especially in computer world) 1 Kbps is 2^10 bits and 1 Mbps is 2^20 bits. When the number is small, you don't see much difference, however when the number is very big, the difference between the two different conversion would give you huge difference.
Note 3 : The number shows in this table is based on the assumption that all the DL/UL TTI carries only user data (U-Plane Data), but in really you cannot allocate 100% of resources for user data only. There should be a certain portion of overhead (like SIBs, MAC CE, Signaling etc). So real throughput you get will be less than the one listed in this table.
In Release 12, there are other categories in which we can specify DL category and UL category separately as shown below.
ueCapabilityInformation-r8 ue-CapabilityRAT-ContainerList: 1 item Item 0 UE-CapabilityRAT-Container rat-Type: eutra (0) ueCapabilityRAT-Container: .... UE-EUTRA-Capability accessStratumRelease: ... ue-Category: 4 ... nonCriticalExtension ... nonCriticalExtension lateNonCriticalExtension:... .... nonCriticalExtension ue-Category-v1020: 6 ... nonCriticalExtension ... nonCriticalExtension nonCriticalExtension .... nonCriticalExtension ue-Category-v1170: 9 nonCriticalExtension phyLayerParameters-v1250 rf-Parameters-v1250 rlc-Parameters-r12 ue-BasedNetwPerMeasParameters-v1250 ue-CategoryDL-r12 : 14 ue-CategoryUL-r12 : 13 wlan-IW-Parameters-r12 measParameters-r1250 dc-Parameters-r12 mbms-Parameters-r12 mac-Parameters-r12 fdd-Add-UE-EUTRA-Capabilities-v1250 fdd-Add-UE-EUTRA-Capabilities-v1250 sl-Parameters-r12 nonCriticalExtension
< 36.306 v14.5 - Table 4.1A-1: Downlink physical layer parameter values set by the field ue-CategoryDL >
< 36.306 v13.4 - Table 4.1A-2: Uplink physical layer parameter values set by the field ue-CategoryUL >
< 36.306 v12.6 - Table 4.1A-6: supported DL/UL Categories combinations set by the fields ue-CategoryDL and ue- CategoryUL and UE categories to be indicated >
To implement the specified UE category, we need to consider various factors along the full stack. Followings are some parameters above Physical layer.
< 36.306 v12.6 Table 4.1-3: Total layer 2 buffer sizes set by the field ue-Category >
< 36.306 v13.4 Table 4.1A-3: Total layer 2 buffer sizes set by the fields ue-CategoryDL and ue-CategoryUL >
< 36.306 v12.6 Table 4.1-4: Maximum number of bits of a MCH transport block received within a TTI set by the field ue-Category for an MBMS capable UE >
< 36.306 v12.6 Table 4.1-5: Half-duplex FDD operation type set by the field ue-Category for a half-duplex FDD capable UE >
Following table represents the max number of PDCP SDUs for each Category. I think this is just enough to achieve the phy/mac max throughput (Table 4.1-1) when the packet size of user data (e.g, IP data) is very large. If the packet size is very small, you would not achieve the maximum throughput at IP level with this number of PDCP SDUs.
< 36.306 v14.5 Table A-1: Maximum values for DL PDCP SDUs per TTI >
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