Research On The Application Of SDM Theory In MIMO

As a major breakthrough, multiple input multiple output (MIMO) technology is a milestone inthe history of the field of wireless communication. With the introduction of spatial dimensions, itcan exponentially increase the spectral efficiency in the case of the same bandwidth and the sametransmitting power. This thesis mainly does a research on the application of space divisionmultiplexing (SDM) theory in MIMO.MIMO theory derives the formula of channel capacity(CC) for MIMO system on the basis ofShannon formula, and CC is proportional to the number of transmitting and receiving antennas insystem. As multi-antenna being used in MIMO system to transmit signals with the same carrierfrequency in the same time, one physical channel contains multi-correlated sub-channels. So thatthe definition for the independent sub-channel is difficult to be realized, making that CC formuladerived by MIMO theory in mathematics difficult to be established. The directional transmissionbeam with uncertain direction must be produced since interfere among multi-radio waves could notbe avoided, which would form a number of blind spots of radio coverage and an unreasonablewireless communication system.This thesis proposed a scheme of beam-forming in linear array for the directional transmissionbeam with uncertain direction in MIMO system, which is easy to implement and has a highreliability. From the viewpoint of engineering application, on the basis of the analysis of Shannontheorem and phase-controlled antenna array (PCA), a multiple-antenna system model is presented,named as SHPCA model, in which PCA is used to produce a narrow directional radio beam withvery high power efficiency to form SDM. Compared with the traditional CC formula, SHPCAmodel is more intuitive to reflect the SDM function and indicate the effect of the equipments ofantenna on CC.