Hi Keith,

On Sun, Feb 24, 2019 at 05:04:33PM +0100, Keith wrote:

The new product from Lime is marked to start shipping tomorrow.

That's good news.

As far as I understand it is basically the LimeSDR mini with a GPS disciplined clock and a Raspberry Pi module, so it /should/ run osmo-bts + osmo-trx-lms fine, and without clocking issues.

That is about as much as I know about it, yes.

I was wondering if anybody else has looked at it, has comments, or has or is thinking of ordering one?

I have seen early prototypes at a trade show and have been in some discussion with Lime about it in the past. However, I don't know any more about the device other than what's published by Lime.

It's definitely an interesting device to play with. I'm looking forward to that.

However, irrespective of the stable enough clock reference we are still experiencing a couple of issues when using OsmoTRX with LimeSDR (usb and mini). It's yet to be determined what exactly is the root cause of all of this, as we're using a rather low sample rate and slow, ancient narrow-band systems like GSM/GPRS/EGPRS shouldn't be a challenge at all for powerful SDR devices. It's not clear whether those porblems are caused by the hardware, gateware, USB host controllers, the kernel/drivers, LimeSuite or OsmoTRX.

Several of the problems users are experiencing are USB related. IIRC, the LimeNET micro used some other interface between the LMS-chip and the Raspi compute module than USB. So it may be that the USB related troubles are becoming irrelevant on this new platform.

I'd definitely love to see the Osmocom stack perform better with LimeSDR based devices, but I have the feeling that a significant amount of debugging is required, and the number of areas required to understand make the number of people available to work on them quite small: One needs to understand the GSM radio interface, the Osmocom stack, LimeSuite, USB protocol and Linux system level instrumentation / debugging of realtime/latency issues which is IMHO a rather rare combination of expert areas to come by :/

Please note I'm not trying to discourage anyone from buying/using LiemSDR devices. I'm just saying that so far, particularly with the Osmocom stack, there are some [so far] hard to resolve problems with the existing USB-based devices. Any help in those areas is very much appreciated!

Regards, Harald