[USRP-users] Loading USRP X3x0 by baseband processing functions
marcus.mueller at ettus.com
Wed Oct 15 04:56:23 EDT 2014
sorry, I can't tell you what your host must look like for your specific
application, because that is a crucial part of your job as an
application designer, and I don't know how much processing power you'll
need for that task. Simply go for workstation as fast as you can afford.
 Assuming you don't want to wait days on your X3x0 FPGA image to be
generated, you'll have workstation around that has a vast amounts of RAM
and quite possibly a high-performance RAID, and that will be a good
starter for beginning your development on. Upgrade later if necessary.
On 15.10.2014 10:38, Birhane Alemayoh wrote:
> Dear Marcus,
> On Tue, Oct 14, 2014 at 9:15 AM, Birhane Alemayoh <birhanea at gmail.com>
>> Dear Marcus,
>> Thank you so much, Your ideas and links are very helpful1
>> On Thu, Oct 9, 2014 at 8:19 PM, Marcus Müller <marcus.mueller at ettus.com>
>>> Hi Birhane,
>>> On 09.10.2014 19:04, Birhane Alemayoh wrote:
>>>>> However, a complete GSM stack is a big thing, and I don't see much use
>>>>> implementing it in FPGA rather than host code, especially since
>>> working GSM
>>>>> base stations already exist (openBTS).
>>>> My system is supposed to capture and process downlink and uplink GSM
>>>> signals in real time from the air using this X310 device.
>>> OpenBTS  does that with USRPs on a host.
>>>> My system is
>>>> shall work under frequency hopping environment which requires strict
>>>> time requirement.
>>>> We believe that this requirement is difficult to handle
>>>> by processing the signal in the host.
>>> It is. But it has been done :)
>>>> This is the reason why we prefer to
>>>> write FPGA code.
>>> Wow, that's dedication. I'd *definitely* spend more time making sure
>>> things can't be done in host code than spending manyears of development
>>> on FPGA hardware.
>>> Since you're asking us for advice, I'd expect you / your company to be
>>> not very experienced in the implementation of communication standards on
>>> FPGAs -- deciding early you want to do *everything* in the FPGA this
>>> early into your development doesn't sound very wise. Re-inventing the
>>> wheel actually sounds bad. And not looking up the capabilities of
>>> openBTS with USRPs instead of believing requirements are hard to meet
>>> with software sounds like a mistake, but one that is easily corrected ;)
>>>> So what do you comment/recommend for this?
>>> Doing what all the industry has been doing for 20 years: Doing only the
>>> really necessary part of processing in hardware, and moving higher level
>>> functionality to general purpose processors.
> One more question please!
> You told me that implementing most of the signal processing is preferred in
> the host PC. However, my requirement is to capture and process multiple
> simultaneous GSM conversations (uplink and downlink) from the air. This
> could be up to 8 different ARFCN channels in which each channel has 8 time
> slots according to the GSM standard. Basically what we are doing is
> implementing GSM interception using the open software and hardware
> technologies. So what should be the performance or specification of the
> host PC?
> Thank you again!
>> Seriously, look at the
>>> Osmocom BB project : Even the Motorola C115  brick of a cheap
>>> consumer mobile phone does its baseband processing in software.
>>> Seriously, I think it will be easier to instantiate a general purpose
>>> CPU in the FPGA and just run the baseband processing software on there
>>> rather than doing everything in real FPGA hardware.
>>>> Thank you
>>> Hope you find the links I share helpful!
More information about the USRP-users