EM9191 - RSSI send in spontaneous report (BIM , cid = 'signal-state' ) is not consistant with CSQ

IoT Modules
1

Currently RSSI level send in BIM by the modem is 23 as inthe following when no attenuation is applied:
2023-09-18_13:35:38.87689 >>>>>> service = ‘basic-connect’ (a289cc33-bcbb-8b4f-b6b0-133ec2aae6df)
2023-09-18_13:35:38.87690 >>>>>> cid = ‘signal-state’ (0x0000000b)

2023-09-18_13:35:38.87691 >>>>>> Fields:
2023-09-18_13:35:38.87691 >>>>>> Rssi = ‘23’
2023-09-18_13:35:38.87694 >>>>>> ErrorRate = ‘99’
2023-09-18_13:35:38.87695 >>>>>> SignalStrengthInterval = ‘5’
2023-09-18_13:35:38.87696 >>>>>> RssiThreshold = ‘2’
2023-09-18_13:35:38.87696 >>>>>> ErrorRateThreshold = ‘4294967295’
2023-09-18_13:35:38.87697 >>>>>> RsrpSnr = ‘{
2023-09-18_13:35:38.87698 >>>>>> }’

the AT+CSQ command gives 31 which is not consistent.

Consequently Signal Strength calculation is 70% instead of 100%.

Thanks for your support

2

what is the return of AT!GSTATUS?
what FW are you using?

3

I don’t have the result of AT!GSTATUS? but we are directly connected to a simulator by cabling.

The software use is SWIX55C_03.09.06.00-001_GENERIC_030.038_000

Regards

4

you can double check with the value in AT!GSTATUS? and see if it matches with your setup

5

Here is GSTATUS response which seems coherent with our set-up:

Current Time: 72954 Temperature: 43
Thermal Mitigation Level: 0
Reset Counter: 1 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B1 LTE bw: 10 MHz
LTE Rx chan: 300 LTE Tx chan: 18300
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: NOT REGISTERED IMS mode: Normal
IMS Srv State: NO SMS,UNKNOWN VoIP

PCC RxM RSSI: -49 PCC RxM RSRP: -73
PCC RxD RSSI: — PCC RxD RSRP: —
PCC RxM1 RSSI: — PCC RxM1 RSRP: —
PCC RxD1 RSSI: — PCC RxD1 RSRP: —
PCC Tx Power: -41 TAC: 0001 (1)
RSRQ (dB): -6.5 Cell ID: 01a2d001 (27447297)
SINR (dB): 29.8

NR5G band: — NR5G bw: —
NR5G Tx Power: — NR5G Tx chan: —
NR5G Rx chan: — NR5G RSRP (dBm): —
NR5G RSRQ (dB): — NR5G SINR (dB): —

6

Ok, then you can use this command instead of at+csq

7

We are using the spontaneous message as explained above, at+csq is correct, GSTATUS is correct, but not the sponatenous one.

Do you confirm there is an issue with this message ? If, yes what is the next step.

Thanks

8

I don’t know how you get this spontaneous message …
By QMI?
By mbimcli command?
By MBPL SDK API?

9

By mbim, it is the NDIS_WWAN_SIGNAL_STATE.

10

mbimcli is a 3rd party application, not developed by Sierra
Not quite sure how to convert this “RSSI+ Signal strength interval + RSSI threshold” into dbm unit as stated in AT!GSTATUS.

why can’t you use AT command instead?
Have you tried the MBPL SDK?

11

This value is supposed to be between 0 and 31. It should be 31 in this case.

The mbim is a third party but the porting is serria scope i supposed.

We will need to workaound and it will be great that you fix this issue in a future release.

12

why can’t you use AT command instead?
Have you tried the MBPL SDK?

Have you contacted distributor on this?

I don’t think this is in the scope of SWI module
I tested on LTE module EM7565, it has same deviation:



owner@ubuntu:~$ sudo mbimcli -d /dev/cdc-wdm0 --query-signal-state
[/dev/cdc-wdm0] Signal state:
	          RSSI [0-31,99]: '10'
	     Error rate [0-7,99]: '99'
	Signal strength interval: '5'
	          RSSI threshold: '2'
	    Error rate threshold: 'unspecified'


at+Csq                                  
+Csq: 25,99                             
                                        
OK                                      
at!gstatus?                             
!GSTATUS:                               
Current Time:  64               Temperature: 34
Reset Counter: 2                Mode:        ONLINE         
System mode:   LTE              PS state:    Attached     
LTE band:      B1               LTE bw:      15 MHz  
LTE Rx chan:   374              LTE Tx chan: 18374
LTE SCC1 state:NOT ASSIGNED
LTE SCC2 state:NOT ASSIGNED
LTE SCC3 state:NOT ASSIGNED
LTE SCC4 state:NOT ASSIGNED                                                     
EMM state:     Registered       Normal Service                                  
RRC state:     RRC Idle                                                         
IMS reg state: No Srv           IMS mode:    Normal                             
                                                                                
PCC RxM RSSI:  -61              PCC RxM RSRP:  -91                              
PCC RxD RSSI:  -92              PCC RxD RSRP:  -131                             
Tx Power:      --               TAC:         2775 (10101)                       
RSRQ (dB):     -11.8            Cell ID:     00360a20 (3541536)                 
SINR (dB):      3.0                                                             
                                                                                
                                                                                
OK                                                                              
ati3                                                                            
Manufacturer: Sierra Wireless, Incorporated                                     
Model: EM7565                                                                   
Revision: SWI9X50C_01.14.05.00 f546ac jenkins 2020/12/01 03:20:39               
IMEI: 353533103912345                                                           
IMEI SV: 13                                                                     
FSN: UF221731112345                                                             
+GCAP: +CGSM                                                                    
                                                                                
                                                                                
OK