Method for channel estimation, related channel estimator, receiver, and computer program product
An embodiment of a method for channel estimation for an Orthogonal Frequency Division Multiplexing communication system, including estimating a Time Domain Least Squares channel impulse response having a given maximum number of L taps based on a channel covariance matrix Q, and for each tap l=1, . . . , L a respective channel impulse response in the time-domain ĥ l , wherein the channel impulse responses in the time-domain are grouped as a channel impulse response vector in the time domain ĥ. Specifically, an updated channel-impulse-response vector in the time domain {tilde over (h)} is determined by computing for each tap l the solution of the following system: Q 1:l, 1:l {tilde over (h)} l×1 =ĥ 1:l , wherein the updated channel-impulse-response vector in the time domain {tilde over (h)} is computed recursively via a Levinson Durbin algorithm.
1. A method, comprising:
receiving a signal over a channel having a number of paths;
generating first channel-estimation values in response to the signal;
generating each of multiple versions of second channel-estimation values in response to a respective one of the first channel-estimation values, wherein generating each of multiple versions of second channel-estimation values includes,
generating one of the versions of second channel-estimation values in response to one of the first channel-estimation values;
generating each of one or more subsequent ones of the versions of the second channel-estimation values in response to a previous version of the second channel-estimation values and a respective other one of the first channel-estimation values;
generating each of multiple path-number-determination values in response to a respective version of the second channel-estimation values; and
determining the number of paths in response to the path-number-determination values; and
wherein generating the second channel-estimation values is adaptively performed as a function of the determined number of paths.
2. The method of claim 1 wherein receiving the signal includes receiving an orthogonal-frequency-division-multiplexed signal.
3. The method of claim 1 wherein generating the first channel-estimation values includes:
generating frequency-domain channel-estimation values;
converting the frequency-domain channel-estimation values into time-domain channel-estimation values; and
setting the first channel-estimation values equal to at least some of the time-domain channel-estimation values.
4. The method of claim 1 wherein generating each of multiple path-number-determination values includes:
generating an initial value;
generating each of the path-number-determination values in response to the initial value and in response to the respective version of the second channel-estimation values.
5. The method of claim 1 wherein determining the number of paths in response to the path-number-determination values includes:
generating a respective metric in response to each path-number-determination value; and
determining the number of paths to be a number that the metrics indicate is the most likely number of paths.
6. A receiver, comprising:
a node configured to receive a signal over a channel having a number of paths;
a first unit configured to generate first channel-estimation values in response to the signal;
a second unit configured to generate each of multiple versions of second channel-estimation values in response to a respective one of the first channel-estimation values, the second unit further configured to generate one of the versions of second channel-estimation values in response to one of the first channel-estimation values and to generate each of one or more subsequent ones of the versions of the second channel-estimation values in response to a previous version of the second channel-estimation values and a respective other one of the first channel-estimation values;
a third unit configured to generate each of multiple path-number-determination values in response to a respective version of the second channel-estimation values; and
a fourth unit configured to determine the number of paths in response to the path-number-determination values; and
wherein the second unit is configured to generate the second channel-estimation values adaptively as a function of the determined number of paths.
7. A system, comprising:
a node configured to receive a signal over a channel having a number of paths;
a receiver coupled to the node and including
a first unit configured to generate first channel-estimation values in response to the signal;
a second unit configured to generate each of multiple versions of second channel-estimation values in response to a respective one of the first channel-estimation values, the second unit further configured to generate one of the versions of second channel-estimation values in response to one of the first channel-estimation values and to generate each of one or more subsequent ones of the versions of the second channel-estimation values in response to a previous version of the second channel-estimation values and a respective other one of the first channel-estimation values, and wherein the second unit is configured to generate the second channel-estimation values adaptively as a function of a determined number of paths;
a third unit configured to generate each of multiple path-number-determination values in response to a respective version of the second channel-estimation values; and
a fourth unit configured to determine the number of paths in response to the path-number-determination values; and
a transmitter coupled to the receiver through a wireless link having the determined number of paths.
8. A non-transitory computer-readable medium storing instructions that, when executed by at least one computing machine, cause the at least one computing machine:
to generate first channel-estimation values in response to a signal received over a channel having a number of paths;
to generate each of multiple versions of second channel-estimation values in response to a respective one of the first channel-estimation values by generating one of the versions of second channel-estimation values in response to one of the first channel-estimation values and by generating each of one or more subsequent ones of the versions of the second channel-estimation values in response to a previous version of the second channel-estimation values and a respective other one of the first channel-estimation values, wherein the second channel-estimation values are generated adaptively as a function of a determined number of paths;
to generate each of multiple path-number-determination values in response to a respective version of the second channel-estimation values; and
to determine the number of paths in response to the path-number-determination values.