Channel estimation using reduced-complexity cascaded one-dimensional filtering

Apparatus, comprising:

• a receiver, which is configured to receive signals that are transmitted over a communication channel in multiple blocks that are transmitted in respective frequency bins during respective time intervals, some of the blocks in a predefined subset of the frequency bins containing reference signals;
• and
• a channel estimation unit, which is configured to compute an estimate of the communication channel for a given block transmitted during a respective time interval by:
• defining a time-domain filter having first and second parts;
• computing respective interim filtering results for the blocks transmitted in the respective time interval in the respective frequency bins belonging to the predefined subset, by filtering one or more of the reference signals transmitted in the respective frequency bins of the block, such that a first subset of the reference signals is filtered using the first part of the time-domain filter and a second subset of the reference signals is filtered using the second part of the time-domain filter;
• and
• combining the interim filtering results, produced using the first and second parts of the time-domain filter, to produce the estimate of the communication channel for the given block.