This paper analyzes the performance of phase

feedback, quasi-orthogonal space-time block codes (QOSTBC)

and Extended OSTBC systems in the presence of

feedback delay, feedback error and amount of channel

feedback. Space-time code constructed for nT transmit

antennas can easily be extended to nT×p antennas transmit

based on a feedback of only p-1 bits. This paper shows that

more feedback bits (more than p-1 bits) in ideal system

(EOSTBC system with no feedback delay and no feedback

error) cause no more considerable performance in the

system. But in the inaccurate feedback information with

increasing feedback bits from p-1 bits decrease sensitivity of

system and increase performance considerably. This paper

obtains an upper bound for phase feedback error respect to

number of feedback bits. Moreover it shows that the system

can select adaptively one of the three modes, phase only

feedback, EO-STBC and QO-STBC with respect to

reliability and amount of feedback information.