ABSTRACT
A new technology being developed to overcome space limitations on handheld wireless devices is distributed or virtual multiple-input multiple-output (MIMO). MIMO technology is becoming a reality in consumer applications. Simpler versions of MIMO include single-input, multiple-output, where only the receiver has multiple antennas, and multiple-input, single-output, where only the transmitter has multiple antennas. The availability of multiple antennas at the receiver, the transmitter, or both, offers new possibilities for increased data rates and range in wireless systems. Baseband variable gain amplifiers are typically used in wireless receivers to amplify the received signal to the full range of the analog-to-digital converter. MIMO can operate in two general modes: spatial diversity, where the same information is encoded in multiple antennas, thus introducing redundancy and improving the reliability of the link, and spatial multiplexing, where the different antennas process differentdata streams resulting in improved spectral utilization.
