Main goal of this work is to give insight on the possible performance improvement arising in the wireless local ad-hoc access from the synergic cooperation of two emerging paradigms, multi-antenna and cognitive radios. The target is the competitive maximization of each access rate in presence of multiple-access interference (MAI) induced by the other accessing terminals. Being the radios cognitive, they are capable to autonomously learn the ambient-context and, then, self-configure their access strategy via suitable power-allocation, that is, time-frequency-code-space signal-shaping. Furthermore, a generalized approach is developed to allow the node to access with a (possibly hybrid) scheme to the medium by combining different x-DMA strategies under QoS-guaranteed access policy.