Re: [Discuss-gnuradio] Agile Solutions is Pleased to announce USRP STAR. Yet another addition to GNURADIO

[Matt Ettus]

On 04/16/2011 11:15 AM, address@hidden wrote:
> Hi Marcus,
> 
>  
> 
> Welcome to Agile Solutions.
> 
>  
> 
> Yes, it uses both common clock and common LO.  Theres no phase tracking
> required due to common LO with cycle slip. This is main requirement for
> MIMO systems for Space Time(STBC) and Space Frequency(SFBC) Codes.
> 
>  
> 
> Although, diversity only systems needs only common clock. Either TX or
> RX. There were fundamental issues when we used USRP1 to detect this
> problem. We had extensive analysis and solid theoretical analysis to
> prove this. Although this analysis and material is not property of Agile
> Solutions, we would not like to comment more on this.  


Dear Mr. Agile Solutions,

You appear to have a fundamental misunderstanding of MIMO systems in
general, and of the design and function of the USRP in particular.  The
USRP1 (as well as all of our other products) is fully MIMO capable.  It
does not suffer from cycle slips, and all oscillators are fully coherent
so the phases "track".

Many papers have been written by people using USRPs for MIMO, including
with STBC and SFBC, as well as phased arrays.  For example, a 30-second
search on Google finds this one right away:

        http://newport.eecs.uci.edu/~hyousefi/publ/sdrMC08.pdf

Matt Ettus
President, Ettus Research LLC