  We investigate the special case of diamond relay comprising a Gaussian
channel with identical frequency response from the user to the relays and
fronthaul links with limited rate from the relays to the destination. We use
the oblivious compress and forward (CF) with distributed compression and decode
and forward (DF) where each relay decodes the whole message and sends half of
its bits to the destination. We derive achievable rate by using time-sharing
between DF and CF. It is proved that optimal CF-DF time sharing is advantageous
over superposition of CF and DF. The optimal time sharing proportion between DF
and CF and power and rate allocations are different at each frequency and are
fully determined.
