  Diamond relay channel model, as a basic transmission model, has recently been
attracting considerable attention in wireless Ad Hoc networks. Node cooperation
and opportunistic scheduling scheme are two important techniques to improve the
performance in wireless scenarios. In the paper we consider such a problem how
to efficiently combine opportunistic scheduling and cooperative modes in the
Rayleigh fading scenarios. To do so, we first compare the throughput of SRP
(Spatial Reused Pattern) and AFP (Amplify Forwarding Pattern) in the
half-duplex case with the assumption that channel side information is known to
all and then come up with a new scheduling scheme. It will that that only
switching between SRP and AFP simply does little help to obtain an expected
improvement because SRP is always superior to AFP on average due to its
efficient spatial reuse. To improve the throughput further, we put forward a
new processing strategy in which buffers are employed at both relays in SRP
mode. By efficiently utilizing the links with relatively higher gains, the
throughput can be greatly improved at a cost of queuing delay. Furthermore, we
shall quantitatively evaluate the queuing delay and the tradeoff between the
throughput and the additional queuing delay. Finally, to realize our developed
strategy and make sure it always run at stable status, we present two criteria
and an algorithm on the selection and adjustment of the switching thresholds.
