Patent ID: 8885757
Filing Date: 2014-11-11
Classification: H04B

Abstract:
1. A system comprising: a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches; a radio distribution network (RDN) connected to the MIMO receiving system with an antenna array of K antennas, the RDN comprising at least one beamformer with k weighting circuits and one radio frequency (RF) signal combiner configured to combine signals coming from the antennas feeding the respective beamformer into a combined signal, wherein k, K and N are positive integers and wherein k is greater than 1 and K is greater than N, wherein the RDN is tuned for optimal performance using channel estimation of individual contributing antennas of the RDN; a signal processing control module configured to: tune the K antennas, wherein the tuning is carried out based on RDN calibration data; and generate said RDN calibration data, based on at least one of: offline and real time procedures for eliminating or reducing systematic errors and unpredictable errors, wherein the calibration is carried out as follows: using a given beamformer antenna for receiving, while disconnecting other antennas in the same beamformer; channel estimating the signals received from a serving transmitting station: for each possible phase and gain setting, for each possible switch setting, and for each possible combiner; selecting as an anchor or reference point one of said settings, and comparing the channel estimations for all other selected settings to the anchor's channel estimation; creating a calibration table using a deviation between the anchor setting and other settings; and repeating the calibration process for all antennas and for all beamformers in the RDN.