Method, software and device for generating channel estimates

1. A method of generating channel estimates of a communication channel in an OFDM system, comprising:

receiving reference symbols from at least one time frequency observation block of a predetermined block size in frequency and time;

generating subspace-transformed reference symbols from the received reference symbols; and

subspace filtering the subspace-transformed reference symbols to generate a channel estimate for a communication channel target time;

wherein a latency between a communication channel time instant of a currently received reference symbol and the communication channel target time is smaller than the observation block size in time.

2. The method of claim 1 , wherein the subspace filtering is based on subspace-transformed reference symbols from a current incompletely subspace-transformed time-frequency observation block.

3. The method of claim 2 , wherein the current incompletely transformed time-frequency observation block includes reference symbols received up to the communication channel time instant of the currently received reference symbol.

4. The method of claim 2 , wherein the subspace filtering is based on subspace-transformed reference symbols from a plurality of current incompletely subspace-transformed time-frequency observation blocks, the plurality of current incompletely subspace-transformed time-frequency observation blocks are arranged coincident in time dimension and adjacent to one another in frequency dimension.

5. The method of claim 2 , wherein the subspace filtering is further based on subspace-transformed reference symbols from a past fully subspace-transformed time-frequency observation block.

6. The method of claim 5 , wherein the subspace filtering is further based on subspace-transformed reference symbols of a plurality of past fully subspace-transformed time-frequency observation blocks, the plurality of past fully subspace transformed time-frequency observation blocks are arranged coincident in time dimension and adjacent to one another in frequency dimension.

7. The method of claim 1 , wherein the latency is set to a fixed predetermined value through subspace filtering of the at least one time-frequency observation block.

8. The method of claim 1 , further comprising:

performing transformed channel post-processing in the subspace to generate a state estimate of the subspace transformed channel; and

performing the subspace filtering based further on the state estimate of the subspace-transformed channel.

9. The method of claim 8 , wherein transformed channel postprocessing is performed on time-frequency observation block rate.

10. The method of claim 8 , wherein transformed channel post-processing comprises one or more of the group consisting of Kalman-filtering, AR-filtering, RLS-filtering, and IIR filtering with fixed or adaptive forgetting factor.

11. The method of claim 8 , wherein the subspace filtering is based on a plurality of state estimates of the subspace-transformed channel, wherein the plurality of state estimates are based on subspace-transformed reference symbols of a plurality of past fully transformed time frequency observation block which are arranged coincident in time dimension and adjacent to one another in frequency dimension.

12. A non-transitory computer readable medium, comprising instructions which, if executed, cause one or more processors to

receive reference symbols from at least one time frequency observation block of a predetermined block size in frequency and time;

generate subspace-transformed reference symbols from the received reference symbols; and

subspace filter the subspace-transformed reference symbols to generate a channel estimate for a communication channel target time;

wherein a latency between a communication channel time instant of a currently received reference symbol and the communication channel target time is smaller than the observation block size in time.

13. A device for generating channel estimates of a communication channel in an OFDM system, comprising:

a subspace transformer to generate subspace-transformed reference symbols from received reference symbols of at least one time-frequency observation block of a predetermined block size in frequency and time; and

a subspace filter to generate a channel estimate for a communication channel target time by filtering the subspace transformed reference symbols;

wherein a latency between a communication channel time instant of a currently received reference symbol and the communication channel target time is smaller than the observation block size in time.

14. The device of claim 13 , wherein the subspace filter is configured to filter subspace-transformed reference symbols from a current incompletely subspace-transformed time frequency observation block.

15. The device of claim 13 , further comprising:

a transformed channel post-processing filter to generate a state estimate of the subspace-transformed channel, wherein the subspace filter performs subspace filtering based further on the state estimate of the subspace-transformed channel.