Frequency response calibration of synchronized mimo measurement receivers with local and remote transmitters

Abstract

Techniques are disclosed related to calibrating and operating a multiple input multiple output (MIMO) radio system. In some embodiments, a dual mode calibration may be employed to calibrate a remote transmitter (RT). During a first, Sparse Full System Calibration (SFSC) mode, the RT may be physically connected to the MIMO radio system. In some embodiments, first and second equalizers may be derived for each of the RT and a local transmitter (LT), respectively. During a subsequent, Real-time Calibration (RTC) mode, the RT may be located remotely from the MIMO radio system, and the RT may be configured to communicate with the MIMO radio system over the air via an antenna. In the RTC mode, third equalizers may be derived for the LT. The RT may then be calibrated based on an equalizer that is derived from each of the first, second, and third equalizers. As one non-limiting example, the techniques described herein may enable real-time calibration for the RT even while the RT is located remotely from the MIMO radio system. In different embodiments, the calibration may be achieved by deriving either fractionally spaced frequency domain equalizers, or time domain equalizers.