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EM7455 - 30Mbps down/0.26Mbps up?

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EM7455 - 30Mbps down/0.26Mbps up?

Posted: Sun Aug 23, 2020 10:32 am
by sam1220
I've been struggling with an embedded EM7455 device for several months now and after trying a whole host of options, I'm throwing myself at the mercy of other experts for help. The EM7455 is installed in an embedded edge device (Core i7) that runs Ubuntu 18.04 server. Nothing magical here.

I've had terrible upload speeds from this device from the start. No matter what we do the upload speed is ALWAYS 0.26Mbps via speedtest-cli. We initially tried an external antenna, basic omnidirectional antenna mounted to a large metal cabinet with a great ground plane. Results were the same, 0.26Mbps upload.

We tried changing the firmware to generic from the stock Verizon firmware. Same, 0.26Mbps. We ensured that we were using the latest firmware from Sierra Wireless, SWI9X30C_02.33.03.00, no change - 0.26Mbps. We've tried different versions of ModemManager, no change. We even thought it might be the device itself so we ordered 2 new EM7455s, also no change.

Most recently we installed a Wilson Wideband 8.5dBi directional antenna and no matter where we aimed it, 0.26Mbps. Download speeds with the Wilson improved a lot - 30Mbps.

Thinking that perhaps we were just in a bad area, though, we tethered the device to a phone on the same network. We were able to get 5/5Mbps via Wifi, tethered. So that told us that it wasn't some strange network/propagation issue, and that it was actually possible to get decent speeds.

So why is this EM7455 stuck at 0.26Mbps?! Help!

Thanks... Sam

Re: EM7455 - 30Mbps down/0.26Mbps up?

Posted: Sun Aug 23, 2020 12:08 pm
by Didneywhorl
Which cellular provider are you using and what plan on that are you using?

What are you signal numbers? RSSI?CSQ?RSRP?RSRQ?
An AT!GSTATUS? output would do wonders to tell info too.

Re: EM7455 - 30Mbps down/0.26Mbps up?

Posted: Sun Aug 23, 2020 12:42 pm
by sam1220
Didneywhorl wrote: ↑Sun Aug 23, 2020 12:08 pm Which cellular provider are you using and what plan on that are you using?

What are you signal numbers? RSSI?CSQ?RSRP?RSRQ?
An AT!GSTATUS? output would do wonders to tell info too.
Provider is Verizon. Here is the output from ModemManager:

Code: Select all

  --------------------------------
  General  |            dbus path: /org/freedesktop/ModemManager1/Modem/0
           |            device id: d3c2e8d7e5a4c5687ab669a594496794d55526e9
  --------------------------------
  Hardware |         manufacturer: Sierra Wireless, Incorporated
           |                model: EM7455
           |             revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
           |         h/w revision: 1.0
           |            supported: gsm-umts, lte
           |              current: gsm-umts, lte
           |         equipment id:
  --------------------------------
  System   |               device: /sys/devices/pci0000:00/0000:00:14.0/usb1/1-8
           |              drivers: qcserial, qmi_wwan
           |               plugin: Sierra
           |         primary port: cdc-wdm0
           |                ports: ttyUSB0 (qcdm), ttyUSB2 (at), cdc-wdm0 (qmi), 
           |                       cdc-wdm1 (qmi), wwp0s20f0u8i8 (net), wwan1 (net)
  --------------------------------
  Numbers  |                  own:
  --------------------------------
  Status   |                 lock: sim-pin2
           |       unlock retries: sim-pin (3), sim-pin2 (3), sim-puk (10), sim-puk2 (10)
           |                state: connected
           |          power state: on
           |          access tech: lte
           |       signal quality: 67% (recent)
  --------------------------------
  Modes    |            supported: allowed: 3g; preferred: none
           |                       allowed: 4g; preferred: none
           |                       allowed: 3g, 4g; preferred: 3g
           |                       allowed: 3g, 4g; preferred: 4g
           |              current: allowed: 3g, 4g; preferred: 4g
  --------------------------------
  Bands    |            supported: utran-1, utran-3, utran-4, utran-5, utran-8, utran-2, 
           |                       eutran-2, eutran-4, eutran-5, eutran-13
           |              current: utran-1, utran-3, utran-4, utran-5, utran-8, utran-2, 
           |                       eutran-2, eutran-4, eutran-5, eutran-13
  --------------------------------
  IP       |            supported: ipv4, ipv6, ipv4v6
  --------------------------------
  3GPP     |                 imei:
           |          operator id: 311480
           |        operator name: Verizon 
           |         registration: home
  --------------------------------
  3GPP EPS | ue mode of operation: csps-2
  --------------------------------
  SIM      |            dbus path: /org/freedesktop/ModemManager1/SIM/0
  --------------------------------
  Bearer   |            dbus path: /org/freedesktop/ModemManager1/Bearer/0
For the other parameters:

Code: Select all

!GSTATUS: 
Current Time:  952551           Temperature: 74
Reset Counter: 1                Mode:        ONLINE         
System mode:   LTE       


AT!LTECA?
Hardware:
LTEB1: B8, 
LTEB2: B2, B5, B12, B13, B29, 
LTEB3: B7, B20, 
LTEB4: B4, B5, B12, B13, B29, 
LTEB5: B2, B4, B30, 
LTEB7: B3, B7, B20, 
LTEB8: B1, 
LTEB12: B2, B4, B30, 
LTEB13: B2, B4, 
LTEB20: B3, B7, 
LTEB25: 
LTEB26: 
LTEB29: 

at!band=?
Index, Name,                        GW Band Mask     L Band Mask      TDS Band Mask
00, All bands                     0002000007C00000 000000000000101A 0000000000000000
01, Europe 3G                     0002000000400000 0000000000000000 0000000000000
That's all GSTATUS gives me but from what I've read there should be more. I'm connecting via minicom to /dev/ttyUSB2. The modem is connected and modemmanager is running. I followed the tutorial here, too, but the result from GSTATUS? was the same.

Re: EM7455 - 30Mbps down/0.26Mbps up?

Posted: Sun Aug 23, 2020 6:04 pm
by Yipzy
If it's doing CA, try to have it to connect to each single band only without CA and see if upload speed will improve or not.

Re: EM7455 - 30Mbps down/0.26Mbps up?

Posted: Thu Aug 27, 2020 3:03 pm
by sam1220
More info... I finally got the correct output from the terminal session. Here are all the relevant numbers. What is confounding to us though is that the DL speeds are 30+Mbps, but upload never moves off 0.26Mbps. The signal numbers here look terrible, but we have a high gain yagi connected and a laptop tethered to an iphone on the same network gets 5Mbps synchronous.

Code: Select all

Manufacturer: Sierra Wireless, Incorporated
Model: EM7455
Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
MEID: A00000AC911DFD
ESN: 12802151217, 8020D331
IMEI: 
IMEI SV: 20
FSN: LF015547080310
+GCAP: +CGSM


OK

PRI Part Number: 9909765
Revision: 001.000
Customer: Generic-M2M

Carrier PRI: 9999999_9904780_SWI9X30C_02.33.03.00_00_VERIZON_002.079_001
Carrier PRI: 9999999_9904594_SWI9X30C_02.32.11.00_00_ATT_002.070_000
Carrier PRI: 9999999_9905153_SWI9X30C_02.24.05.06_00_BELL_001.005_000
Carrier PRI: 9999999_9904609_SWI9X30C_02.32.11.00_00_GENERIC_002.064_000
Carrier PRI: 9999999_9905151_SWI9X30C_02.24.03.00_00_ROGERS_001.001_000
Carrier PRI: 9999999_9904779_SWI9X30C_02.32.11.00_00_SPRINT_002.062_000
Carrier PRI: 9999999_9905152_SWI9X30C_02.32.11.00_00_TELUS_001.040_000
Carrier PRI: 9999999_9904930_SWI9X30C_02.24.03.00_00_VODAFONE_001.001_000

OK

!GSTATUS: 
Current Time:  1306897          Temperature: 73
Reset Counter: 1                Mode:        ONLINE         
System mode:   LTE              PS state:    Attached     
LTE band:      B2               LTE bw:      10 MHz  
LTE Rx chan:   1000             LTE Tx chan: 19000
LTE CA state:  NOT ASSIGNED
EMM state:     Registered       Normal Service 
RRC state:     RRC Connected  
IMS reg state: Full Srv         IMS mode:    Normal       

PCC RxM RSSI:  -85              RSRP (dBm):  -112
PCC RxD RSSI:  -97              RSRP (dBm):  -140
Tx Power:      --               TAC:         640E (25614)
RSRQ (dB):     -13.4            Cell ID:     0187B52C (25670956)
SINR (dB):      6.6


OK

!LTEINFO: 
Serving:   EARFCN MCC MNC   TAC      CID Bd D U SNR PCI  RSRQ   RSRP   RSSI RXLV
             1000 311 480 25614 0187B52C  2 3 3  10 448 -12.6 -111.1  -77.0 --

IntraFreq:                                          PCI  RSRQ   RSRP   RSSI RXLV
                                                    448 -12.6 -111.1  -77.0 --

InterFreq: EARFCN ThresholdLow ThresholdHi Priority PCI  RSRQ   RSRP   RSSI RXLV

WCDMA:     UARFCN ThreshL ThreshH Prio PSC   RSCP  ECN0 RXLV

OK

+CGDCONT: 1,"IPV4V6","ims","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
+CGDCONT: 2,"IPV4V6","vzwadmin","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
+CGDCONT: 3,"IPV4V6","ne01.VZWSTATIC","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
+CGDCONT: 4,"IPV4V6","vzwapp","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
+CGDCONT: 5,"IPV4V6","vzw800","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
+CGDCONT: 6,"IPV4V6","vzwclass6","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0

OK

+CGPADDR: 1,38.0.16.2.17.48.37.80.0.0.0.0.92.235.82.150

OK

+cops: 0,0,"Verizon ",7

OK

+cops: (2,"Verizon ","Verizon ","311480",7),(1,"Extended Network","Extended","310410",2),(3,"311 490","311 490","311490",7),(3,"T-Mobile","T-Mobile","310260",7),(3,"T-Mobile","T-Mobile","310260",2),(1,"Extended Network","Extended","310410",7),(1,"313 100","313 100","313100",7),,(0,1,2,3,4),(0,1,2)

Re: EM7455 - 30Mbps down/0.26Mbps up?

Posted: Thu Aug 27, 2020 4:56 pm
by Yipzy
sam1220 wrote: ↑Thu Aug 27, 2020 3:03 pm More info... I finally got the correct output from the terminal session. Here are all the relevant numbers. What is confounding to us though is that the DL speeds are 30+Mbps, but upload never moves off 0.26Mbps. The signal numbers here look terrible, but we have a high gain yagi connected and a laptop tethered to an iphone on the same network gets 5Mbps synchronous.
RSRP (dBm): -140

That is terrible and likely the cause of it. Compare the RSRP from your iphone by going to field test mode.

1. Turn off your Wi-Fi before beginning
2. Dial *3001#12345#*
3. Press the call button
4. Field test mode menu will show up
5. Go to LTE > Serving Cell Measurements

If it's better than your setup then that's why it's getting 5Mbps UL. My suggestion is try to switch it to the generic firmware with the right config version number associated with it to see if it helps. If not, check the connection of the pigtails going to the modem to see if it's loose or not then try to adjust your yagis and make sure they are not misaligned for polarization too if they are dual yagis.
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