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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).

 

 

< LTE - SIB 1>

 

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

 

 

< LTE - SIB 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.

 

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

 

 

< WCDMA - SIB 19 >

 

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