USRP as Relay Node

Hi Everyone,

I have a WBX series daughterborad in USRP N200, which I want to use as
relay node. As per the details mentioned on ettus research website it
can
operate on full duplex mode with different set of frequencies.

The designed flowgraph for relay node USRP is attached herewith for
reference. Whenever I execute this following error received.

“RuntimeError: ValueError: Could not resolve device hint “” to a single
device”

I am waiting for an urgent reply. Thanks.

Regards,
Syed Aqeel R.