| Beamforming and diversity are two different configuration schemes of downlink in MIMO systems and both of them can improve system performance effectively. If beamforming and transmit diversity are combined properly, more channel capacity is likely to be acquired. How to realize integrate is our interesting problem.In a MISO system, multiple transmit antennas are divided into several sub-arrays. Perfect beamforming is assumed for each sub-array and space-time coding is applied to the sub-arrays to achieve transmit diversity. The influence of different hybrid scheme on the channel outage capacity is studied in this system when channel undergoing Rayleigh and Rician fading, and outage probability, rician factor and spread angular are considered. The result shows that under the condition that the number of transmit antenna is invariable, beamforming becomes asymptotical optimization choice with the increasing of Rician factor K if outage probability is fixed. Fading becomes partially correlative when angle spread is existent, so the number of transmit diversity branches is larger than that in the condition of ideally correlative hypothesis, and transmit diversity is superior asymptotically when spread angle is increased.More advantage of multiple transmitter antennas would be revealed on the basis of this paper, and the conclusion in this paper can help us make the optimal choice between different hybrid schemes.
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