Patent ID: 8260208

Claim:
A radio channel estimator for estimating a first radio channel to obtain a first radio channel estimate, the first radio channel being comprised in a multiple input multiple output (MIMO=multiple input multiple output) radio channel, the MIMO radio channel extending between at least a first transmit antenna, a second transmit antenna and a receive antenna, the first radio channel extending between the first transmit antenna and the receive antenna, comprising: a receiver for receiving a reference symbol transmitted by the second transmit antenna; an estimator for estimating a second radio channel based on the reference symbol, the second radio channel extending between the second transmit antenna and the receive antenna; and a processor for processing the estimate of the second radio channel based on a spatial property of the MIMO radio channel to obtain the first radio channel estimate, wherein the MIMO radio channel has a coherence time, a coherence bandwidth and a coherence length, a spacing between the first transmit antenna and the second transmit antenna being less than the coherence length, and no reference symbol is provided by the first transmit antenna within the coherence time or the coherence bandwidth.