Patent ID: 8565352

Claim:
A method of compensating for imbalances between the In-phase (I) and Quadrature (Q) components (IQ imbalance) of communication signals processed by a multi-carrier multiple conversion receiver operative in a radio frequency (RF) wireless communication network, the receiver having two or more receiver chains, each operative to downconvert signals modulated onto different RF carrier frequencies to baseband via at least one intermediate frequency (IF), the method comprising: processing, in a first receiver chain, a first signal modulated onto a first RF carrier; processing, in a second receiver chain that utilizes one or more RF or IF components of the first receiver chain, a second signal modulated onto a second RF carrier, different from the first carrier; downconverting the first and second signals to baseband by conversion from the respective RF carrier frequencies to an IF, and by further conversion from the IF to baseband; processing known reference signals in each receiver branch; deriving IQ imbalance estimates associated with each receiver chain as the values that best match each received signal with one of the corresponding known reference signal or the corresponding known reference signal modified by the corresponding channel estimate; wherein deriving IQ imbalance estimates associated with each receiver chain as the values that best match each received signal with the corresponding known reference signal further comprises: estimating an IQ-imbalance-plus-channel matrix comprising IQ imbalance values scaled by channel estimates; and normalizing the IQ-imbalance-plus-channel matrix to remove the channel estimates; and compensating the received signals for the IQ imbalance based on the IQ imbalance estimates.