Sunday, February 6, 2022

MTN Ghana 4x2/4x4 MIMO and 256QAM now widely deployed in Accra

Instead of 2 antennas on the tower, there are 4.

This leads to a slightly improved experience with phones and modems that have 2 antennas, and a substantially improved experience with phones and modems that have 4.

2021 phones with 4 antennas may cost 3000GHS or more (new condition).

Rank 4, which is depicted by the image above, is when there are 4 antennas in the mobile phone and 4 antennas on the tower, and each antenna acts individually for <100Mbps per antenna. It is a separate feature that may be switched on or switched off at certain towers. A tower can be configured to use up to Rank 2, where only 2 antennas act individually and other antennas improve the experience. Only one antenna in a mobile phone may transmit, multiple may receive.

256QAM DL(downlink) and 64QAM UL(uplink) are additionally deployed. These allow the speed to improve even more, but cannot be used when the 4G signal isn't clear enough and will be automatically switched off in those cases.

Poor signal? 4TX may improve speeds even in cell edge conditions.

For 2CA (4G+), any of these frequencies may be aggregated in any way for downlink: B7(5MHz, 37/50/100Mbps), B7(20MHz, 150/200/400Mbps), B20(15MHz, 110/150Mbps).

Tested cell sites used 2TX for Band 20.

Not all of the speed may be visible to the user - if 256QAM and Rank 4 are used (391.656Mbps with no 4G+), speed may be 'spent on' extra FEC and retransmissions, both of which are necessary if the signal isn't perfect. Rank and/or modulation order may be lower if the signal isn't good enough.

These can only improve the speed between the tower and the mobile phone. Speeds between the tower and the website you're connecting to may be lower. An example of an AMBR value used is 500Mbps, but sometimes it's only a suggestion.



Very nice, now why is my network slow?

1) It depends on where you're located compared to the location and rotation of the tower's sectors. Sectors may tilt the airwaves down in addition to physically being rotated. This is an example that approximates how speeds may vary while connected to a sector aimed north, and with one other tower that uses the same frequencies.

Distance affects the signal. Obstacles inside the Fresnel zone affect the signal. Reflections and high speed affect the signal.


How antenna elements are placed (there are 10 "X"s in the example at the beginning of the page) and the rest of the design in the sector molds the emitted signal in a way that approximately flattens it. It goes further, but it's also vertically narrower. It is possible to be located where the signal isn't focused at. In addition to the main lobe, there are sidelobes.

Other towers that use the same frequencies cause interference during normal operation. Southeast and southwest sectors in that example cause interference as well.



2) It's only the speed between the tower and the mobile phone. Sometimes this has been favored over the speed between the tower and the rest of the network.



3) You share available resources with others. The resources to share are aimed north in that example.



Example: RRCConnectionReconfiguration


DL-DCCH-Message

  message: c1 (0)

    c1: rrcConnectionReconfiguration (4)

      rrcConnectionReconfiguration

        rrc-TransactionIdentifier: 0

        criticalExtensions: c1 (0)

          c1: rrcConnectionReconfiguration-r8 (0)

            rrcConnectionReconfiguration-r8

              measConfig

                measObjectToRemoveList: 1 item

                  Item 0

                    MeasObjectId: 1

                measObjectToAddModList: 2 items

                  Item 0

                    MeasObjectToAddMod

                      measObjectId: 1

                      measObject: measObjectEUTRA (0)

                        measObjectEUTRA

                          carrierFreq: 3075

                          allowedMeasBandwidth: mbw25 (2)

                          .... ..0. presenceAntennaPort1: False

                          neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)

                  Item 1

                    MeasObjectToAddMod

                      measObjectId: 2

                      measObject: measObjectEUTRA (0)

                        measObjectEUTRA

                          carrierFreq: 3200

                          allowedMeasBandwidth: mbw100 (5)

                          ...0 .... presenceAntennaPort1: False

                          neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)

                          measCycleSCell-r10: sf160 (0)

                reportConfigToRemoveList: 4 items

                  Item 0

                    ReportConfigId: 1

                  Item 1

                    ReportConfigId: 2

                  Item 2

                    ReportConfigId: 3

                  Item 3

                    ReportConfigId: 6

                reportConfigToAddModList: 4 items

                  Item 0

                    ReportConfigToAddMod

                      reportConfigId: 1

                      reportConfig: reportConfigEUTRA (0)

                        reportConfigEUTRA

                          triggerType: event (0)

                            event

                              eventId: eventA3 (2)

                                eventA3

                                  a3-Offset: 3dB (6)

                                  ...0 .... reportOnLeave: False

                              hysteresis: 1dB (2)

                              timeToTrigger: ms320 (8)

                          triggerQuantity: rsrp (0)

                          reportQuantity: both (1)

                          maxReportCells: 4

                          reportInterval: ms480 (2)

                          reportAmount: infinity (7)

                  Item 1

                    ReportConfigToAddMod

                      reportConfigId: 2

                      reportConfig: reportConfigEUTRA (0)

                        reportConfigEUTRA

                          triggerType: event (0)

                            event

                              eventId: eventA2 (1)

                                eventA2

                                  a2-Threshold: threshold-RSRP (0)

                                    threshold-RSRP: -112dBm (28)

                              hysteresis: 2dB (4)

                              timeToTrigger: ms640 (11)

                          triggerQuantity: rsrp (0)

                          reportQuantity: both (1)

                          maxReportCells: 1

                          reportInterval: ms5120 (6)

                          reportAmount: infinity (7)

                  Item 2

                    ReportConfigToAddMod

                      reportConfigId: 3

                      reportConfig: reportConfigEUTRA (0)

                        reportConfigEUTRA

                          triggerType: event (0)

                            event

                              eventId: eventA2 (1)

                                eventA2

                                  a2-Threshold: threshold-RSRP (0)

                                    threshold-RSRP: -126dBm (14)

                              hysteresis: 1dB (2)

                              timeToTrigger: ms40 (1)

                          triggerQuantity: rsrp (0)

                          reportQuantity: both (1)

                          maxReportCells: 1

                          reportInterval: ms480 (2)

                          reportAmount: infinity (7)

                  Item 3

                    ReportConfigToAddMod

                      reportConfigId: 4

                      reportConfig: reportConfigEUTRA (0)

                        reportConfigEUTRA

                          triggerType: event (0)

                            event

                              eventId: eventA1 (0)

                                eventA1

                                  a1-Threshold: threshold-RSRP (0)

                                    threshold-RSRP: -126dBm (14)

                              hysteresis: 1dB (2)

                              timeToTrigger: ms40 (1)

                          triggerQuantity: rsrp (0)

                          reportQuantity: both (1)

                          maxReportCells: 1

                          reportInterval: ms480 (2)

                          reportAmount: infinity (7)

                measIdToRemoveList: 4 items

                  Item 0

                    MeasId: 1

                  Item 1

                    MeasId: 2

                  Item 2

                    MeasId: 3

                  Item 3

                    MeasId: 6

                measIdToAddModList: 4 items

                  Item 0

                    MeasIdToAddMod

                      measId: 1

                      measObjectId: 1

                      reportConfigId: 1

                  Item 1

                    MeasIdToAddMod

                      measId: 2

                      measObjectId: 1

                      reportConfigId: 2

                  Item 2

                    MeasIdToAddMod

                      measId: 3

                      measObjectId: 2

                      reportConfigId: 3

                  Item 3

                    MeasIdToAddMod

                      measId: 4

                      measObjectId: 2

                      reportConfigId: 4

                speedStatePars: release (0)

                  release: NULL

              radioResourceConfigDedicated

                mac-MainConfig: explicitValue (0)

                  explicitValue

                    drx-Config: setup (1)

                      setup

                        onDurationTimer: psf2 (1)

                        drx-InactivityTimer: psf30 (9)

                        drx-RetransmissionTimer: psf2 (1)

                        longDRX-CycleStartOffset: sf40 (3)

                          sf40: 5

                    timeAlignmentTimerDedicated: infinity (7)

                    mac-MainConfig-v1020

                physicalConfigDedicated

                  pdsch-ConfigDedicated

                    p-a: dB0 (4)

                  soundingRS-UL-ConfigDedicated: release (0)

                    release: NULL

                  antennaInfo: explicitValue (0)

                    explicitValue

                      transmissionMode: tm4 (3)

                      codebookSubsetRestriction: n4TxAntenna-tm4 (3)

                        n4TxAntenna-tm4: ffffffffffffffff [bit length 64, 1111 1111  1111 1111  1111 1111  1111 1111  1111 1111  1111 1111  1111 1111  1111 1111 decimal value 18446744073709551615]

                      ue-TransmitAntennaSelection: release (0)

                        release: NULL

                  schedulingRequestConfig: setup (1)

                    setup

                      sr-PUCCH-ResourceIndex: 33

                      sr-ConfigIndex: 5

                        [Periodicity: 10]

                        [Subframe Offset: 0]

                      dsr-TransMax: n64 (4)

                  cqi-ReportConfig-r10

                    cqi-ReportAperiodic-r10: setup (1)

                      setup

                        cqi-ReportModeAperiodic-r10: rm31 (4)

                        aperiodicCSI-Trigger-r10

                          trigger1-r10: 40 [bit length 8, 0100 0000 decimal value 64]

                          trigger2-r10: c0 [bit length 8, 1100 0000 decimal value 192]

                    nomPDSCH-RS-EPRE-Offset: 0dB (0)

                    cqi-ReportPeriodic-r10: setup (1)

                      setup

                        cqi-PUCCH-ResourceIndex-r10: 18

                        cqi-pmi-ConfigIndex: 83

                        cqi-FormatIndicatorPeriodic-r10: widebandCQI-r10 (0)

                          widebandCQI-r10

                        ri-ConfigIndex: 322

                        ...0 .... simultaneousAckNackAndCQI: False

                        csi-ConfigIndex-r10: release (0)

                          release: NULL

                    csi-SubframePatternConfig-r10: release (0)

                      release: NULL

                  pucch-ConfigDedicated-v1020

                    pucch-Format-r10: format3-r10 (0)

                      format3-r10

                        n3PUCCH-AN-List-r13: 4 items

                          Item 0

                            n3PUCCH-AN-List-r13 item: 0

                          Item 1

                            n3PUCCH-AN-List-r13 item: 1

                          Item 2

                            n3PUCCH-AN-List-r13 item: 2

                          Item 3

                            n3PUCCH-AN-List-r13 item: 3

                  cqi-ReportConfigPCell-v1250

                    altCQI-Table-r12: allSubframes (0)

              nonCriticalExtension

                nonCriticalExtension

                  otherConfig-r9

                    reportProximityConfig-r9

                  nonCriticalExtension

                    sCellToAddModList-r10: 1 item

                      Item 0

                        SCellToAddMod-r10

                          sCellIndex-r10: 1

                          cellIdentification-r10

                            physCellId-r10: 299

                            dl-CarrierFreq-r10: 3200

                          radioResourceConfigCommonSCell-r10

                            nonUL-Configuration-r10

                              dl-Bandwidth-r10: n100 (5)

                              antennaInfoCommon-r10

                                antennaPortsCount: an4 (2)

                              phich-Config-r10

                                phich-Duration: normal (0)

                                phich-Resource: one (2)

                              pdsch-ConfigCommon-r10

                                referenceSignalPower: 16 dBm

                                p-b: 1

                          radioResourceConfigDedicatedSCell-r10

                            physicalConfigDedicatedSCell-r10

                              nonUL-Configuration-r10

                                antennaInfo-r10

                                  transmissionMode-r10: tm4 (3)

                                  codebookSubsetRestriction-r10: 00000000ffffffff [bit length 64, 0000 0000  0000 0000  0000 0000  0000 0000  1111 1111  1111 1111  1111 1111  1111 1111 decimal value 4294967295]

                                  ue-TransmitAntennaSelection: release (0)

                                    release: NULL

                                pdsch-ConfigDedicated-r10

                                  p-a: dB-3 (2)

                              ul-Configuration-r10

                                cqi-ReportConfigSCell-r10

                                  cqi-ReportModeAperiodic-r10: rm31 (4)

                                  nomPDSCH-RS-EPRE-Offset-r10: 0dB (0)

                              cqi-ReportConfigSCell-v1250

                                altCQI-Table-r12: allSubframes (0)


The reconfiguration message sent to other mobile phones may differ; and the message may differ in other cases.

No comments:

Post a Comment

Other Pages