In this paper, a threshold‐based selection relaying scheme that employs space‐time coding (STC) strategy is considered in a decode and forward (DF) cooperative network with multiple‐input–multiple‐output relays. One of the serious imperfections affecting these systems is error propagation on the source‐relay link, which culminates in intersymbol interference (ISI). Two scenarios are studied. In the first scenario, a new beamforming method is proposed for removing ISI between symbols of distributed space‐time coding scheme caused by erroneous detection of symbols at relays. It is demonstrated that this system is more power efficient in comparison to other systems without beamforming. In the second scenario, a new central STC that we nominate its orthogonal‐STC generator is proposed for multiple‐input–multiple‐output relays. The proposed new transmission scheme, in this case, removes ISI between …
