Re: [Discuss-gnuradio] USRP2 MIMO system implementation

[Josh Blum]

On 08/28/2012 12:19 AM, Pan, Luyuan wrote:
> Hello,
> I want to implement a MIMO system using USRP2, I just have USRP2s and
> MIMO cable.
> 1. Do I have to use an external clock source ?

No. With the mimo cable, you can share a clock reference between a pair
of devices

> 2. I searched the maillist and found: Each USRP2 can handle 1 antenna
> with most daughterboards, or 2 if you
> have your own external RF sections connected to the USRP2 at IF.
> Does it mean I should buy "external RF sections" to use 2 antennas on 1
> USRP2? Or where can I get them?

You should select a daughterboard based on the desired frequency
coverage. Typically transceiver boards have 1 tx frontend and 1 rx
frontend. The TVRX2, which is RX only, has 2 rx frontends.

> 3. If I want to build a 2X2 MIMO system,-- 2 USRP2s, 1 MIMO cable, the
> "external RF sections" said above, -- Is that enough?
> 

Correct.

You may also find these notes helpful:
http://files.ettus.com/uhd_docs/manual/html/sync.html

-josh