DSL Advances

11.5. MIMO Channel Identification

All the methods for multiuser coordination need information about the multiple-input multiple-output (MIMO) channel, H(f) or its magnitude |H(f)| and/or the the noise spectra on each line's output. This information may be derived by each line itself without coordination. However, coordination may allow more swift and easy determination of the characteristics. With no coordination, the identification of crosstalking coupling into a specific channel is called “blind” training as the data sequences on other lines are unknown. When these sequences are known either through coordination or because a regularly inserted synchronization pattern on another line has been identified, the DSM system “uses training” or simply ...