[manet] Ad-Hoc compared to TETRA

Hello!

I have read a little about Ad-Hoc and also a little about TETRA (Terrestrial Trunked Radio) which is defined by ETSI.

As I understand TETRA and AD-Hoc are very much adressing the same users, where the main users are police, ambulance, firemen, but also civil users and military users may be relevant.

The technology is very different for TETRA and Ad-Hoc. TETRA uses a

GSM alike principle with switches and base stations, while Ad-Hoc uses

nodes that are combined routers and terminals (no base stations).

But although the technique is different the features seem to be very much the same with security, priority, group calls etc.

From this I wonder if TETRA and Ad-Hoc are competing technologies in the same market or complementary in some ways. Is it e.g. relevant to use an Ad-Hoc network out in the field in a rescue operation and then use TETRA for communication towards hospitals etc?
I also wonder what the benefits of using Ad-Hoc compared to TETRA are.
Can anyone help me?

Thanks for your help!

Best Regards Berner