Sierra Wireless EM7455, Band Lock and Carrier Aggregation

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terryjett
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Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by terryjett » Mon Nov 18, 2019 4:46 pm

Have a EM7455 and working just fine with WE826 and AT&T. Since working with the Sierra Cards is quite new to me, not sure I am understanding band locking and aggregation correctly.

Currently the EM7455 is locking onto band 5 and using band 2 for CA:

Code: Select all

at!gstatus?
!GSTATUS: 
Current Time:  2333		Temperature: 47
Reset Counter: 1		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B5     		LTE bw:      5 MHz   
LTE Rx chan:   2535		LTE Tx chan: 20535
LTE CA state:  ACTIVE      		LTE Scell band:B2     
LTE Scell bw:15 MHz  		LTE Scell chan:1025
EMM state:     Registered     	Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  		

PCC RxM RSSI:  -88		RSRP (dBm):  -111
PCC RxD RSSI:  -84		RSRP (dBm):  -112
SCC RxM RSSI:  -60		RSRP (dBm):  -98
SCC RxD RSSI:  -64		RSRP (dBm):  -101
Tx Power:      16		TAC:         6A2C (27180)
RSRQ (dB):     -10.2		Cell ID:     07FC9602 (133993986)
SINR (dB):     11.6


OK
Yes, signal little crazy, using WE826 stock antennas in wooded area:)

What I wish to accomplish is use band 2 and band 4 (CA) as they are the best around here. When I run:

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AT!ENTERCND="A710"
AT!BAND=10,"B2",0,0000000000000002
AT!BAND=11,"B4",0,0000000000000008
AT!BAND=0F,"ATT 2&4",0,000000000000000A
AT!BAND=0F
AT!RESET
End up with no carrier aggregation and will not lock onto band 2 at all and CA state is not assigned :

Code: Select all

at!gstatus?
!GSTATUS: 
Current Time:  298		Temperature: 43
Reset Counter: 1		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B4     		LTE bw:      10 MHz  
LTE Rx chan:   2000		LTE Tx chan: 20000
LTE CA state:  NOT ASSIGNED
EMM state:     Registered     	Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  		

PCC RxM RSSI:  -69		RSRP (dBm):  -98
PCC RxD RSSI:  -69		RSRP (dBm):  -96
Tx Power:      9		TAC:         6A2C (27180)
RSRQ (dB):     -10.5		Cell ID:     07FC9617 (133994007)
SINR (dB):     12.4
Is there not a way to force the EM7455 to use band 2 with CA band 4, or vice versa?

Band 5 around these parts is AOL dialup speed. Band 4 is pretty good in off peak and band 2 rocks most all the time.

Hope not a totally silly question, just not quite comfortable with SW cards yet.
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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by JimHelms » Mon Nov 18, 2019 5:33 pm

Hmm...

You can receive Band 5 which aggregates with Band 2
You can receive Band 4 which will not aggregate with Band 2

You may check and see if AT&T have primary bands it uses (required) to aggregate with another secondary band. Seems like this was the case at one point.

Also, and you may already know this, when creating a group of bands, you do not have to define each individual band.

For instance, and using your example of combining Band 2 and 4, all that must be done is define the group:

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AT!BAND=10,"ATT 2,4",0,A
and then to lock onto that group:

Code: Select all

AT!BAND=10
This makes it easier to define several groups of bands (with different group ID numbers), for instance:

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AT!BAND=10,"ATT 2,4" ,0,A
AT!BAND=11,"ATT 2,5" ,0,12
AT!BAND=12,"ATT 2,4,5 ",0,1A
AT!BAND=13,"ATT 2,4,12 ",0,80A
And, then call one of the groups:

Code: Select all

AT!BAND=13
Makes it a lot simpler to switch back and forth with a single command.

Also, you may want to download the latest Excel cheat-sheet for creating the bands which remove the leading zeros.

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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by JimHelms » Mon Nov 18, 2019 5:59 pm

One more thing you might want to do is run this command and see what bands aggregate with one another:

Code: Select all

AT!LTECA?

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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by terryjett » Mon Nov 18, 2019 6:09 pm

You may have a good point about band combination allowed, did not think about that. Will study up on it.

Now understand why the spreadsheet I downloaded is nothing like the screenshots in thread post! All the zero's were missing so thought it was my version of office or something stripping them.

I followed your example of:

Code: Select all

AT!BAND=10,"ATT 2,4",0,A
AT!BAND=10
AT!RESET
The results are a bit confusing, but may very well be related to band combinations allowed:

Code: Select all

Cell ID :17 (23)
 
LTE Band :
B4 (Bandwidth 10 MHz) aggregated with:
B4 (Bandwidth 5 MHz)
 
Channel : 2000, 2275

AT!GSTATUS?
!GSTATUS: 
Current Time:  478		Temperature: 46
Reset Counter: 1		Mode:        ONLINE         
System mode:   LTE        	PS state:    Attached     
LTE band:      B4     		LTE bw:      10 MHz  
LTE Rx chan:   2000		LTE Tx chan: 20000
LTE CA state:  ACTIVE      		LTE Scell band:B4     
LTE Scell bw:5 MHz   		LTE Scell chan:2275
EMM state:     Registered     	Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  		

PCC RxM RSSI:  -72		RSRP (dBm):  -103
PCC RxD RSSI:  -71		RSRP (dBm):  -101
SCC RxM RSSI:  -74		RSRP (dBm):  -108
SCC RxD RSSI:  -70		RSRP (dBm):  -105
Tx Power:      13		TAC:         6A2C (27180)
RSRQ (dB):     -14.4		Cell ID:     07FC9617 (133994007)
SINR (dB):     11.6

OK
Did not use the 710 command first, so could see this:

Code: Select all

AT!BAND=?
Index, Name
00, All bands
01, Europe 3G
02, North America 3G
06, Europe
07, North America
08, WCDMA ALL
09, LTE ALL
0F, ATT 2&4
10, ATT 2,4
11, B4

OK
Did the AT!LTECA? but really not sure what looking at or how to use results:

Code: Select all

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: 
LTEB30: B5, B12, 
LTEB41: B41, 

Permitted Bands:
Empty

Prune_ca_combos:
Empty

OK
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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by JimHelms » Mon Nov 18, 2019 6:59 pm

Notice above on the LTEB4 (which represents Band 4) shows it can aggregate with:

Code: Select all

LTEB4: B4, B5, B12, B13, B29
Now, notice your last GSTATUS return:

Code: Select all

System mode:   LTE        	PS state:    Attached     
LTE band:      B4     		LTE bw:      10 MHz  
LTE Rx chan:   2000		LTE Tx chan: 20000
LTE CA state:  ACTIVE      		LTE Scell band:B4     
LTE Scell bw:5 MHz   		LTE Scell chan:2275
We see that Band 4 is aggregating with Band 4.

Also notice that Band 4 does not include Band 2 for CA.

When we look at what Band 2 aggregates with:

Code: Select all

LTEB2: B2, B5, B12, B13, B29,
Again we see no Band 4.

So that would explain why you could not get Band 2 and 4 to work with each other.

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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by terryjett » Mon Nov 18, 2019 7:04 pm

Ok, good lesson - have already learned a lot:)

What about LTEB5: B2, B4, B30, - LTEB12: B2, B4, B30, or LTEB13: B2, B4, ?

How can I use that to obtain the combination or am I missing the picture here?
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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by terryjett » Tue Nov 19, 2019 8:52 am

I see others here that have asked about at&t bands 2 and 4. One example is:

viewtopic.php?f=16&t=33&hilit=mc7700+at ... t=30#p3318
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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by JimHelms » Tue Nov 19, 2019 10:25 am

terryjett wrote:
Mon Nov 18, 2019 7:04 pm
What about LTEB5: B2, B4, B30, - LTEB12: B2, B4, B30, or LTEB13: B2, B4, ?

Code: Select all

AT!BAND=10,"ATT 2,4,5,30",0,2000001A
AT!BAND=11,"ATT 2,4,12,30",0,2000080A
AT!BAND=13,"ATT 2,4,13",0,100A
Note, that you have no control over which band is used as the primary band.

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Re: Sierra Wireless EM7455, Band Lock and Carrier Aggregation

Post by terryjett » Tue Nov 19, 2019 10:39 am

JimHelms wrote:
Tue Nov 19, 2019 10:25 am

Code: Select all

AT!BAND=10,"ATT 2,4,5,30",0,2000001A
AT!BAND=11,"ATT 2,4,12,30",0,2000080A
AT!BAND=13,"ATT 2,4,13",0,100A
Note, that you have no control over which band is used as the primary band.
Gotcha. I know the cell site equipment is in charge, just thought the SW card may have some say so, lol.

I have tried many combo's and nothing really working as good as just locking to band 2. Even the examples you provided (tried them last night) use band 4 and never band 2. Will continue to experiment.
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