Project update 2 of 2
New Video Demo of Our Carrier Board in Action!
by Andrew AvtushenkoDear backers,
Thank you for your support of our project. We’re excited to share our latest progress and some great news with you!
Demo Video
First, we’ve just released a video showcasing xMASS SDR in action (Massive MIMO). You can now see its performance - eight channels running at 65 MSps or four channels at 130 MSps on a single CPU, all without any overruns.
We’ve optimized our software to support complex 12-bit I/Q streaming to achive maximum bandwidth utilization without lowering dynamic range. xMASS supports PCIe 3.0 x2 which gives a maximum of 1.969 GB/s of raw badwidth. With 128b PCIe transfer packets, that’s 1.693 GB/s of usable traffic.
| Data format | Maximum rate (8ch) | Maximum rate (4ch) | xMASS Stable rate (8ch) | xMASS Stable rate(4ch) |
|---|---|---|---|---|
| 16 bit I/Q | 52.8 MSps | 105.6 MSps | 48 MSps | 96 MSps |
| 12 bit I/Q | 70.5 MSps | 141.0 MSps | 65 MSps | 130 MSps |
Due to jitter, out of band control traffic, and other service interrupts, we can’t achieve the absolute maximum rates. But we have achieved more than 92% bus utilization without any under-runs. With realtime priorities and other tricks it may be possible to get even few percent more! These 12-bit operations are not convenient for CPU and it took us some time to get AVX2 vector implementation to work fast. But with all the optimization we’ve achieved with PCIe driver communication, data transcoding (complex integer 12 bit -> complex float 32 bit), 2048 FFT of effective 520MSps, converting to log scale, and averaging using just one i7-11800H CPU core. Graph drawing in the video demo was done on a separate thread, but its utilization was below 10%.
These 130MSps@4 / 65MSsps@8 operations are supported in SoapySDR and work well in GNURadio and other software.
Carrier Board Modules Received
We’re also thrilled to announce that we’ve already received the xSDR modules for the xMASS carrier board. This development may allow us to shorten our delivery timeline, getting your xMASS SDR to you even sooner than initially projected.
As a reminder, the campaign is still ongoing, so now this is the best time to secure your xMASS SDR! Once the campaign ends, the price will increase, so we encourage you to back our campaign if you haven’t already.
Thank you once again for your support. We’re looking forward to getting xMASS SDR into your hands!