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 18.104.22.168-1: 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.
plmn-IdentityList: 1 item
cellBarred: notBarred (1)
intraFreqReselection: allowed (0)
.... ..0. csg-Indication: False
q-RxLevMin: -110dBm (-55)
schedulingInfoList: 3 items
si-WindowLength: ms20 (5)
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.
interFreqCarrierFreqList: 1 item
q-RxLevMin: -110dBm (-55)
threshX-High: 4dB (2)
threshX-Low: 2dB (1)
allowedMeasBandwidth: mbw25 (2)
.... .0.. presenceAntennaPort1: False
neighCellConfig: No MBSFN subframes are present in all neighbour cells (1)
q-OffsetFreq: dB3 (18)
interFreqCarrierFreqList-v9e0: 1 item
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.
criticalExtensions: c1 (0)
c1: rrcConnectionReconfiguration-r8 (0)
mac-MainConfig: explicitValue (0)
pucch-Format-r10: channelSelection-r10 (1)
n1PUCCH-AN-CS-r10: setup (1)
n1PUCCH-AN-CS-List-r10: 2 items
sCellToAddModList-r10: 1 item
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
eutra-FrequencyAndPriorityInfoList: 1 item
...0 .... eutraDetection: False
eutra-FrequencyAndPriorityInfoList-v920ext: 1 item
eutra-FrequencyAndPriorityInfoExtensionList: 1 item
measurementBandwidth: mbw75 (4)
0... .... eutraDetection: False