4x4 MIMO modem and 2x2 MIMO external antenna?

[Iridium]

Hello

I wanted to purchase an EM160R card which is a 4x4 MIMO modem. But currently I still only have a 2x2 antenna which I may upgrade later.



I have the following questions:

Q1: In case of a 2x2 MIMO antenna, on which ports should I connect the 2 cables? One antenna cable connects to the “M” labeled connector. Where should I connect the second cable? D/G?

Q2: Is it a problem if I only use the modem in 2x2 MIMO mode? Does the modem detects automatically that 2 outputs aren’t connected to any antenna and won’t use those accordingly?

Q3: Is there an AT command allowing to switch to 2x2 MIMO mode?

Q4: Are all frequencies available on all outputs or do they use different frequencies? In others words, will I be able to use the full spectrum of frequencies with a 2x2 MIMO antenna?
I’m asking this because the Netgear M1 (Snapdragon X16) used 2 antennas for low frequencies and the other 2 for high frequencies (don’t know if it was a hardware limitation or firmware optimization)

Thank you

[Didneywhorl]

Hello

I wanted to purchase an EM160R card which is a 4x4 MIMO modem. But currently I still only have a 2x2 antenna which I may upgrade later.

Welcome to the forum!

I have the following questions:

Q1: In case of a 2x2 MIMO antenna, on which ports should I connect the 2 cables? One antenna cable connects to the “M” labeled connector. Where should I connect the second cable? D/G?

Correct. One goes to M and one goes to D/G. If running 2x2 MIMO only make sure to turn off 4x4 MIMO. Run AT command:

Code: Select all

AT+QCFG="lte4x4mimo/disable",1

',0' to turn it back on.

Q2: Is it a problem if I only use the modem in 2x2 MIMO mode? Does the modem detects automatically that 2 outputs aren’t connected to any antenna and won’t use those accordingly?

Not automatic. Answered above.

Q3: Is there an AT command allowing to switch to 2x2 MIMO mode?

Q4: Are all frequencies available on all outputs or do they use different frequencies? In others words, will I be able to use the full spectrum of frequencies with a 2x2 MIMO antenna?
I’m asking this because the Netgear M1 (Snapdragon X16) used 2 antennas for low frequencies and the other 2 for high frequencies (don’t know if it was a hardware limitation or firmware optimization)

Thank you

I believe it can use all frequencies in either mode, as long as you use the AT command to set it appropriately (2x2 MIMO mode or 4x4 MIMO mode set)

[Iridium]

Thanks for your answer!

Where did you find that instruction, or rather, parameter: AT+QCFG="lte4x4mimo/disable",1 ?
I couldn't find it in the AT commands manual

[Didneywhorl]

When I get a new modem I run through its commands via manual discovery.

ie: I typed in ..

Code: Select all

AT+QCFG=?

...and it gave me a list of commands that all looked interesting.

EM160-AT-Commands-QCFG.png

[Iridium]

Oh, that's great

Thanks.

[Iridium]

I have yet another question.
(I don't know if it worth to open a new topic)

Assume you have a very high gain 2x2 MIMO antenna (like a modified Mikrotik LHG) and, let's say, a standard mid/low gain 2x2 MIMO or even omnis, to form a 4x4 MIMO configuration (+/-22.5° each).

Could the modem deal with such configuration (low + high gain antenna)?
I mean the high gain 2x2MIMO antenna may pick up high frequencies that the mid/low gain antenna won't.

Is the modem "smart" enough to identify which antenna to use for the upload for example?

[Didneywhorl]

Short answer. No the modem is not smart enough to know.

Depends on the modem too. Some modems only use certain frequency ranges on each pair of antenna ports. Like the EM20, I believe it only has the higher frequencies on the second pair.

[wh31415]

Hello! I'm going to piggyback on this discussion since I recently purchased a WiFiX-NEXQ6GO router and an EM160R-GL modem to go with it. I have the same situation as OP--only a 2x2 mimo antenna setup.

1.png

Unfortunately, I haven't been able to get it to actually disable 4x4mimo using the +QCFG command

2.png

Though I can query that setting without an issue.

5.png

Also, possibly related: this is my first modem that supports carrier aggregation, so I've been playing with that. It seems that this command should set it to the particular lte bands that I want (according to (this link)[url]http://www.wirelessjoint.com/viewtopic.php?f=16&t=2187[/url])

For testing, I noticed that I always am connected to LTE Band 2, so I want to disable that and make it connect to a different one

3.png

And it appeared to accept the configuration

4.png

And yes, it successfully connected me to Band 4 instead, so I know that at least one other band besides two is present in my location.

So why can't I get it to use carrier aggregation and connect to at least those two bands simultaneously?


QUESTIONS

• Why can't I disable 4x4 MIMO?

• Why can't I enable carrier aggregation?

• Am I missing some vital command here or something?

Thanks in advance for any hints you might be able to throw my way!

[Didneywhorl]

What firmware version are you using? I'm guessing the latest A05?

Carrier aggregation is controlled by the tower, but if capable the modem should engage when available. Your tower may not allow B4 aggregation maybe? One important thing is that a lot of aggregation is based on the anchor band, meaning the primary serving cell. (AT+QENG="servingcell")

Run the command AT+QCAINFO and see what pops up.

AT+QENG="neighbourcell" should show the bands available to you as well.

[Didneywhorl]

There is a command to basically tell the modem you want it to prefer up to 3 bands.

I think it works on the EM160, I'll have to test sometime:

AT+QCFG="lte/bandprior",<band>,<band>,<band>

[wh31415]

What firmware version are you using? I'm guessing the latest A05?

Carrier aggregation is controlled by the tower, but if capable the modem should engage when available. Your tower may not allow B4 aggregation maybe? One important thing is that a lot of aggregation is based on the anchor band, meaning the primary serving cell. (AT+QENG="servingcell")

Run the command AT+QCAINFO and see what pops up.

AT+QENG="neighbourcell" should show the bands available to you as well.

When I issue AT+GMR it reports:

Code: Select all

AT+GMR
EM160RGLAUR02A05M4G

OK

I'm not sure exactly how to parse that version string, but I see A05 in there towards the end, so I think so?

And for the servingcell:

Code: Select all

AT+QENG="servingcell"
+QENG: "servingcell","NOCONN","LTE","FDD",310,410,7569AAC,97,5330,14,3,3,8011,-90,-18,-59,10,-

OK

And neighbourcell

Code: Select all

AT+QENG="neighbourcell"
+QENG: "neighbourcell intra","LTE",5330,97,-20,-90,-53,0,-,-,-,-,-
+QENG: "neighbourcell intra","LTE",5330,110,-20,-93,-63,0,-,-,-,-,-
+QENG: "neighbourcell intra","LTE",5330,108,-19,-92,-63,0,-,-,-,-,-
+QENG: "neighbourcell intra","LTE",5330,99,-20,-94,-63,0,-,-,-,-,-
+QENG: "neighbourcell intra","LTE",5330,103,-20,-92,-63,0,-,-,-,-,-

OK

I'm fairly new to all of this so I'm not sure exactly what I'm looking at/for.

Back to the MIMO 2x2 topic, do you have any idea why it might be giving me an ERROR response when I try to set the value of lte4x4mimo/disable?

Code: Select all

AT+QCFG="lte4x4mimo/disable",1
ERROR

Which is weird, because as you can see, it IS a supported option, as I can query it and it shows me it is disabled:

Code: Select all

AT+QCFG="lte4x4mimo/disable"
+QCFG: "lte4x4mimo/disable",0

OK

Is there some sort of engineering mode or something that needs to be enabled for it to allow changing that value?

I have a suspicion that some of my problems may be due to the fact that my modem only has antennas attached to the M and D/G connectors on it, as my router enclosure doesn't yet have any additional antenna ports drilled into it, and besides, I only have two antennas to connect to the router at this point.

[wh31415]

There is a command to basically tell the modem you want it to prefer up to 3 bands.

I think it works on the EM160, I'll have to test sometime:

AT+QCFG="lte/bandprior",<band>,<band>,<band>

This is odd... If I query all options for +QCFG, it shows that lte/bandprior is a valid option:

Code: Select all

AT+QCFG=?
+QCFG: "gprsattach",(0,1)
+QCFG: "nwscanseq",(00-0102030405),(0,1)
+QCFG: "rrc",(0-5)
+QCFG: "msc",(0-2)
+QCFG: "sgsn",(0-2)
+QCFG: "hsdpacat",(6,8,10-24)
+QCFG: "hsupacat",(5,6)
+QCFG: "pdp/duplicatechk",(0,1)
+QCFG: "ledmode",(0,1)
+QCFG: "ltesms/format"[,(0-2)]
+QCFG: "ModemRstLevel",(0,1)
+QCFG: "mdlogcfg",(0,1)
+QCFG: "lte4x4mimo/disable",(0,1)
+QCFG: "lte4x4mimo/swmethod",(0,AT)(1,check_PIN68)
+QCFG: "ApRstLevel",(0,1)
+QCFG: "ims",(0,1)
+QCFG: "pcmclk",(0,1)
+QCFG: "thermal/modem"[,<level>,<trig>,<clr>]
+QCFG: "thermal/limit_rates"[,<enable>]
+QCFG: "lte/bandprior",(1-43),(1-43),(1-43)
+QCFG: "qsar/qsardpr",(0,1)
+QCFG: "vts/async",(0,1)
+QCFG: "imsreg/iptype",(0,1)
+QCFG: "sim/onchip",(0,1)
+QCFG: "powerup/regctl",(0,1)
+QCFG: "volte_disable",(0,1)
+QCFG: "sim/clk_freq",(0,1)
+QCFG: "diversity/config",<0-5>,<0-7>,<0-2>
+QCFG: "div_test_mode",<0-1>
+QCFG: "usbid",<vid>,<pid>
+QCFG: "usbcfg",<vid>,<pid>,<diag>,<nmea>,<at_port>,<modem>,<rmnet>,<adb>
+QCFG: "usbnet",<0-3>
+QCFG: "data_interface",(0,1),(0,1)
+QCFG: "stkauto/setupmenutr",(0,1)
+QCFG: "fcc_enable",(0,1)
+QCFG: "soft_hotswap",(0,1),(5-60)

OK

However, if I try to query the current value, it throws an error:

Code: Select all

AT+QCFG="lte/bandprior"
ERROR

And yet it works if I try to set it to a few bands:

Code: Select all

AT+QCFG="lte/bandprior",2,4,17
OK

And now if I try to query the value, it works:

Code: Select all

AT+QCFG="lte/bandprior"
+QCFG: "lte/bandprior",02,04,17

OK

So I guess it will return ERROR if you query an option that is unset?

[Didneywhorl]

I guess so! Sounds odd though. Should have a default, but it may have been an oversight.

[Loudbinary]

When I get a new modem I run through its commands via manual discovery.

ie: I typed in ..

Code: Select all

AT+QCFG=?

...and it gave me a list of commands that all looked interesting.



EM160-AT-Commands-QCFG.png

Good teachings.

[BDF1234]

I'm fairly new to all of this so I'm not sure exactly what I'm looking at/for.

Back to the MIMO 2x2 topic, do you have any idea why it might be giving me an ERROR response when I try to set the value of lte4x4mimo/disable?

Code: Select all

AT+QCFG="lte4x4mimo/disable",1
ERROR

Which is weird, because as you can see, it IS a supported option, as I can query it and it shows me it is disabled:

Code: Select all

AT+QCFG="lte4x4mimo/disable"
+QCFG: "lte4x4mimo/disable",0

OK

Did you ever figure this out? I have the same issue on my EM160.

[LanGhost]

Issue from official forum:

Code: Select all

// Change mimo switch mode:
// 0 - by AT command
// 1 - by state of PIN68

AT+QCFG="lte4x4mimo/disable",0

// Change mimo mode:
// 0 - MIMO 4x4 mode
// 1 - MIMO 2x2 mode

AT+QCFG="lte4x4mimo/disable",1