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Author Topic: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology  (Read 7655 times)

ejs

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At the weekend, I stumbled upon some source code for the Broadcom xdslctl program. Apparently, for devices based on the newer BCM63138 family of chips, there's a new info switch xdslctl info --RNC_QLN. I had no idea what RNC referred to at the time, but now I've just found this Broadcom press release (from October 2015):

Broadcom Adds Advanced Noise Cancellation Technique to DSL Gateways

I suppose people using a BCM63138 based device, and with an interest in DSL stats, might like to compare the QLN with the RNC_QLN.
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digitalnemesis

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #1 on: August 08, 2016, 09:35:57 PM »

How do I enable this on a VMG8924 with the aforementioned chipset?

Sounds very interesting.

Cheers
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digitalnemesis

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #2 on: August 08, 2016, 09:49:20 PM »

Just tried it:

Code: [Select]
> xdslctl info --RNC_QLN
xdslctl: too many parameters

Any ideas?

Code: [Select]
xdslctl info --QLN works
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NewtronStar

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burakkucat

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #4 on: August 08, 2016, 10:49:58 PM »

Just tried it:

Code: [Select]
> xdslctl info --RNC_QLN
xdslctl: too many parameters

Any ideas?

I would suggest taking a look at the help option --

xdslctl --help

That should show you the various implemented options (plus any flags) to the xdslctl command.
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digitalnemesis

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #5 on: August 08, 2016, 11:15:58 PM »

Code: [Select]
> xdslctl --help
Usage: xdslctl start [--up] <configure command options>
       xdslctl stop
       xdslctl connection [--up] [--down] [--loopback] [--reverb]
           [--medley] [--noretrain] [--L3] [--diagmode] [--L0]
           [--tones <r1-r2,r3-r4,...>] [--normal] [--freezeReverb] [--freezeMedl                                                                                                              ey]
       xdslctl configure/configure1 [--mod <a|d|l|t|2|p|e|m|M3|M5|v>] [--lpair <                                                                                                              (i)nner|(o)uter>]
           [--trellis <on|off>] [--snr <snrQ4>] [--bitswap <on|off>] [--sesdrop                                                                                                               <on|off>]
           [--sra <on|off>] [--CoMinMgn <on|off>] [--i24k <on|off>] [--phyReXmt                                                                                                               <0xBitMap-UsDs>]
           [--Ginp <0xBitMap-UsDs>] [--TpsTc <0xBitMap-AvPvAaPa>] [--monitorTone                                                                                                               <on|off>]
           [--profile <0x00 - 0xFF>|<"8a |8b |8c |8d |12a |12b |17a |30a">] [--u                                                                                                              s0 <on|off>]
           [--dynamicD <on|off>] [--dynamicF <on|off>] [--SOS <on|off>] [--maxDa                                                                                                              taRate <maxDsDataRateKbps maxUsDataRateKbps maxAggrDataRateKbps>]
           [--forceJ43 <on|off>] [--toggleJ43B43 <on|off>]
       xdslctl bert [--start <#seconds>] [--stop] [--show]
       xdslctl afelb [--time <sec>] [--tones] [--signal <1/2/8>]
       xdslctl qlnmntr [--time <sec>] [--freq <msec>]
       xdslctl inm [--start <INMIATO> <INMIATS><INMCC><INM_INPEQ_MODE><INM_INPEQ                                                                                                              _FORMAT>] [--show]
       xdslctl snrclamp [--shape <shapeId>] [--bpshape [bpIndex-bpLevel,]]
       xdslctl nlnm [--show ] [--setThld <Thld_Num_Tones>]
       xdslctl diag [--logstart <nBytes>] [--logpause] [--logstop] [--loguntilbu                                                                                                              fferfull <nBytes>] [--loguntilretrain <nBytes>] [--dumpBuf <sizeKb>]
       xdslctl ntr [--start [output freq(default is 8000)]] [--stop]
       xdslctl info [--state] [--show] [--stats] [--SNR] [--QLN] [--Hlog] [--Hli                                                                                                              n] [--HlinS] [--Bits]
[--pbParams] [--linediag] [--linediag1] [--reset] [--vendor] [--cfg] [--webstats                                                                                                              ]
       xdslctl profile [--show] [--save] [--restore]
       xdslctl --version
       xdslctl --help
 >

I don't see mention of
Code: [Select]
xdslctl info --RNC_QLN
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burakkucat

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #6 on: August 08, 2016, 11:20:58 PM »

I don't see mention of
Code: [Select]
xdslctl info --RNC_QLN

That is what I was suspecting, as a result of your earlier test. All that we can say, with certainty, is that the implementation of the xdslctl command on your device does not have that option.  :-\
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digitalnemesis

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #7 on: August 08, 2016, 11:22:09 PM »

Okay. I wonder which devices based on this chipset actually incorporate this command? Would be interesting to see how it helps.
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NEXUS2345

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #8 on: August 08, 2016, 11:45:33 PM »

I believe that the VMG8924 uses the BCM63168 as opposed to the BCM63138, which would be the issue. The BCM63138 is a newer chip, featuring G.fast support and Wireless-AC integrated. If they did include the BCM63138 it is puzzling to me as why would they release a unit with G.fast support then disable it?  :-\

A possibility is that because the spec is being updated and has not yet been finalised, they may have disabled it so as to keep it as a single chip solution. However, at the same time, the lack of the
Code: [Select]
xdslctl info --RNC_QLN command suggests to me that they have instead gone for a dual chip solution, choosing to use a separate chip for the AC wireless.

It would be nice if someone could open up a VMG8924, as I cannot find details of precisely what chipset it uses.
« Last Edit: August 08, 2016, 11:52:15 PM by NEXUS2345 »
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NEXUS2345

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #9 on: August 08, 2016, 11:57:23 PM »

Also, another point to add on, according to the Zyxel website, the VMG8924 was launched/released around the end of 2014. The BCM63138 was not announced until October 2015, so evidently it is impossible for the VMG8924 to use this chipset. This explains the lack of command.

On another note, further digging has revealed this patent filing, which explains the underpinnings of the technology: https://www.google.com/patents/US8605837
« Last Edit: August 09, 2016, 12:00:24 AM by NEXUS2345 »
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digitalnemesis

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #10 on: August 09, 2016, 12:02:51 AM »

You're right, I got mixed up with the chipsets  :lol:

Which modems/routers have this chipset?
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ejs

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #11 on: August 09, 2016, 04:32:32 PM »

BCM63138/7 devices:

Netgear D7000
TP-Link VR900 v2 (probably not yet available, and likely to be difficult to obtain stats from)
BT Smart Hub 6 (no stats from that obviously)
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NEXUS2345

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #12 on: August 09, 2016, 07:15:15 PM »

I find that very interesting. The Smart Hub having that chipset means it will be possibly G.fast capable, which explains the timing considering that they are beginning the G.fast rollout this year.
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ejs

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #13 on: August 09, 2016, 07:24:13 PM »

The chip may be G.fast capable, but the devices may not be. It may be similar to how existing Broadcom VDSL2 chips may all be profile 30a capable, when used with a suitable extra chip, and so some devices only go up to profile 17a (which doesn't really matter, we don't use profile 30a and aren't likely to).
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gladwyn

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Re: Broadcom BCM63138 Reference Noise Cancellation (RNC) technology
« Reply #14 on: December 06, 2016, 06:52:35 AM »

The chip may be G.fast capable, but the devices may not be. It may be similar to how existing Broadcom VDSL2 chips may all be profile 30a capable, when used with a suitable extra chip, and so some devices only go up to profile 17a (which doesn't really matter, we don't use profile 30a and aren't likely to).

So I need a faster device. Any recommendations?
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