Band 66
As LTE evolves, many new bands has been added. In Release 13, several new bands including the Band 66 were added as shown below.
< [36.521-1 V13.2.0] - Table 5.2-1: E-UTRA operating bands >
< [36.521-1 V13.2.0] - Table 5.4.2.1-1: E-UTRA channel bandwidth >
So what ?
Is there anything special with Band 66 that gets you to create a special note like this ?
In terms of Hardware implementation, I don't think there is any special about this band. It is just addition of a new frequency spectrum.
However, there is a special things about Band 66 in terms of the number. EARFCN (Channel Number) for Band 66 is from 66436 through 57335. In the original ASN design for LTE, they allocated 4 bits (1~64) for Band Indicator and 16 bits (0~66535) for EARFCN. It means, in order to specify Band 66 we need a little bit of redesign RRC message specification (ASN specification) about Band Indicator and EARFCN settings. In this page, I will summarize several issues of Band 66 (mainly with the perspective of RRC message)
Overlapping with existing bands
First, let's get a brief overview of frequency range of Band 66 and check if it is overlapping with any existing bands. As indicated in the table below, Band 66 overlaps completely or partially with several other bands. In some case, it overlapps only downlink part (red) and in some other case it overlaps only uplink part. Of course, there are some cases where it overlaps both uplink and downlink spectrum.
RRC Message Issues
As I mentioned at the beginning, 3GPP ASN was not designed to specify this kind of big number like Band 66, EARFCN 66866 etc. So they need to revise ASN structure of some RRC messages to specify these big numbers. In this section, I will list the RRC messages that uses this newly added IE (Information Element).
As you may know, you need to configure the band indicator in SIB1. To specify the Band greater than 64, a new IE in red is added. To make the red part take effect, you have to set the max value in the existing IE marked in blue.
systemInformationBlockType1
cellAccessRelatedInfo
plmn-IdentityList: 1 item
Item 0
PLMN-IdentityInfo
trackingAreaCode: 0001
cellIdentity: 00000010
cellBarred: notBarred (1)
intraFreqReselection: allowed (0)
.... ..0. csg-Indication: False
cellSelectionInfo
q-RxLevMin: -110dBm (-55)
p-Max: 23dBm
freqBandIndicator: 64
schedulingInfoList: 3 items
si-WindowLength: ms20 (5)
systemInfoValueTag: 0
nonCriticalExtension
lateNonCriticalExtension: 6008
SystemInformationBlockType1-v8h0-IEs
nonCriticalExtension
freqBandIndicator-v9e0: 66
nonCriticalExtension
SIB5 specifies interfrequency neighbour cell info . To specify the EARFCN greater than 65535, a new IE in red is added. To make the red part take effect, you have to set the max value in the existing IE marked in blue.
sib5
interFreqCarrierFreqList: 1 item
Item 0
InterFreqCarrierFreqInfo
dl-CarrierFreq: 65535
q-RxLevMin: -110dBm (-55)
p-Max: 23dBm
t-ReselectionEUTRA: 0s
threshX-High: 4dB (2)
threshX-Low: 2dB (1)
allowedMeasBandwidth: mbw25 (2)
.... .0.. presenceAntennaPort1: False
cellReselectionPriority: 4
neighCellConfig: No MBSFN subframes are present in all neighbour cells (1)
q-OffsetFreq: dB3 (18)
lateNonCriticalExtension: 6100a8c0
SystemInformationBlockType5-v8h0-IEs
nonCriticalExtension
interFreqCarrierFreqList-v9e0: 1 item
Item 0
InterFreqCarrierFreqInfo-v9e0
dl-CarrierFreq-v9e0: 66886
< LTE - RRC Connection Reconfiguration (Adding B66 SCC) >
When you set up Carrier Aggregation with B66 as a SCC, you need to specify B66 EARFCN (big number greater than 65535). To specify the EARFCN greater than 65535, a new IE in red is added. To make the red part take effect, you have to set the max value in the existing IE marked in blue.
rrcConnectionReconfiguration
rrc-TransactionIdentifier: 0
criticalExtensions: c1 (0)
c1: rrcConnectionReconfiguration-r8 (0)
rrcConnectionReconfiguration-r8
radioResourceConfigDedicated
mac-MainConfig: explicitValue (0)
....
physicalConfigDedicated
pusch-ConfigDedicated
...
pucch-ConfigDedicated-v1020
pucch-Format-r10: channelSelection-r10 (1)
channelSelection-r10
n1PUCCH-AN-CS-r10: setup (1)
setup
n1PUCCH-AN-CS-List-r10: 2 items
...
nonCriticalExtension
nonCriticalExtension
nonCriticalExtension
sCellToAddModList-r10: 1 item
Item 0
SCellToAddMod-r10
sCellIndex-r10: 1
cellIdentification-r10
physCellId-r10: 0
dl-CarrierFreq-r10: 65535
radioResourceConfigCommonSCell-r10
...
radioResourceConfigDedicatedSCell-r10
physicalConfigDedicatedSCell-r10
nonUL-Configuration-r10
...
ul-Configuration-r10
cqi-ReportConfigSCell-r10
...
dl-CarrierFreq-v1090: 66886
The Band 66 forced the ASN changes not only for LTE but also for WCDMA. WCDMA SIB 19 carries the neighbour cell of different radio technolgies. To configure Band 66 frequencies in SIB 19, SIB 19 should be revised as follows. To specify the EARFCN greater than 65535, a new IE in red is added. To make the red part take effect, you have to set the max value in the existing IE marked in blue
SysInfoType19
utra-PriorityInfoList
utra-ServingCell
priority: 0
s-PrioritySearch1: 0
threshServingLow: 0
eutra-FrequencyAndPriorityInfoList: 1 item
Item 0
EUTRA-FrequencyAndPriorityInfo
earfcn: 65535
priority: 0
qRxLevMinEUTRA: -64
threshXhigh: 0
threshXlow: 0
...0 .... eutraDetection: False
v920NonCriticalExtensions
sysInfoType19-v920ext
utra-PriorityInfoList-v920ext
eutra-FrequencyAndPriorityInfoList-v920ext: 1 item
Item 0
EUTRA-FrequencyAndPriorityInfo-v920ext
va80NonCriticalExtensions
sysInfoType19-va80ext
vb30NonCriticalExtensions
sysInfoType19-vb30ext
vb50NonCriticalExtensions
sysInfoType19-vb50ext
eutra-FrequencyAndPriorityInfoExtensionList: 1 item
Item 0
EUTRA-FrequencyAndPriorityInfoExtension-vb50ext
earfcn: 66866
measurementBandwidth: mbw75 (4)
priority: 7
qRxLevMinEUTRA: -62
threshXhigh: 4
threshXlow: 2
0... .... eutraDetection: False