Increasing the spectral efficiency in fixed point-to-point microwave radio system using multiple antenna arrays

With new applications for broadband wireless access (BWA) systems increasing, the demand for higher data rates is continuously growing. As ever bandwidth is a scarce resource and there is an obvious need for spectrally more efficient and more reliable wireless access techniques. Multiple-Input-Multiple-Output (MIMO) refers to radio links with multiple antennas at the transmitter and the receiver thus allowing the spatial dimension (spatial diversity) to be exploited to improve the performance and capacity of the wireless link. This promised capacity enhancement has motivated research interest in MIMO and Space Time Coding (STC) for both fixed and mobile radio access including: 3rd Generation (3G) mobile; Point-to-Multipoint (P2MP); and Point-to-Point (P2P) systems, which are becoming an essential component in communication networks. In this paper we present a P2P system that combines both spatial and polarization diversities to offer an increase in spectral efficiency while maintaining an acceptable Bit-Error-Rate (BER) performance in Additive-White-Gaussian-Noise (AWGN) channels.