IQ IMBALANCE ESTIMATION USING BROADCAST SIGNALS

摘要

The present disclosure is described in the exemplary context of a Long Term Evolution (LTE) cellular network and is directed to a method and apparatus for estimating a gain and phase imbalance between an in-phase path and a quadrature path of a receiver operating in such a network. The method and apparatus specifically exploit channel coherence in time and frequency, and the properties of the Primary Synchronization Signal (PSS), and/or the Secondary Synchronization Signal (SSS), and/or information in the Physical Broadcast Channel (PBCH), all of which are defined by the LTE standard, to estimate the gain and phase imbalance of the receiver while it remains connected to a base station to receive data.

主权项

1. A method for estimating a gain and phase imbalance between an in-phase path and a quadrature-phase path of a receiver, the method comprising:
for each of a plurality of subcarrier pairs, adding a first symbol received over a first subcarrier of the subcarrier pair with a complex conjugate of a second symbol received over a second subcarrier of the subcarrier pair to form a statistic, determining two channel estimates using the statistic formed for each of the plurality of subcarrier pairs and using known values of the first and second symbols received over each of the plurality of subcarrier pairs; and estimating the gain and phase imbalance using at least the two channel estimates and the first and second symbols received over each of the plurality of subcarrier pairs.