Soft channel tracking using detection output

1. A method, comprising:

receiving, by a user equipment (UE), a first signal from a transceiver, the first signal including a logarithm likelihood ratio (LLR) symbol detection output from a previously detected symbol;

detecting the LLR symbol detection output using a linear minimum mean square error (LMMSE) method;

determining a symbol probability based on the LLR symbol detection output;

determining a soft mean and a soft variance based on the LLR symbol detection output;

determining a first coefficient and a second coefficient based on the determined symbol probability, the soft mean, the soft variance, a signal to noise ratio (SNR) of the first signal and an SNR of a second signal received by the UE from the transceiver;

determining channel state information (CSI) on a channel between the transceiver and the UE based on the second signal received by the UE from the transceiver, a previous CSI, the first coefficient and the second coefficient; and

tracking the communication channel based on the determined CSI.

2. The method of claim 1 , wherein the first coefficient and the second coefficient are determined based on a channel scaler.

3. The method of claim 1 , wherein the first signal is at least one of a long training field, a high throughput long training field, a very high throughput long training field and another type of training field.

4. The method of claim 1 , wherein the second signal is a data field of a WiFi signal.

5. The method of claim 1 , wherein tracking the communication channel comprises updating the determined CSI when the communication channel changes.

6. The method of claim 5 , wherein recently updated values of CSI are provided a higher weighting when updating the determined CSI when the communication channel changes.

7. An apparatus, comprising:

a memory;

a processor; and

a receiver configured to:

receive a first signal from a transceiver, the first signal including a logarithm likelihood ratio (LLR) symbol detection output from a previously detected symbol,

detect the LLR symbol detection output using a linear minimum mean square error (LMMSE) method;

determine a symbol probability based on the LLR symbol detection output,

determine a soft mean and a soft variance based on the LLR symbol detection output,

determine a first coefficient and a second coefficient based on the determined symbol probability, the soft mean, the soft variance, a signal to noise ratio (SNR) of the first signal and an SNR of a second signal received by the UE from the transceiver,

determine channel state information (CSI) on a channel between the transceiver and the receiver based on the second signal received from the transceiver, a previous CSI, the first coefficient and the second coefficient, and

track the communication channel based on the determined CSI.

8. The apparatus of claim 7 , wherein the first coefficient and the second coefficient are determined based on a channel scaler.

9. The apparatus of claim 7 , wherein the first signal is at least one of a short training field, a long training field, a high throughput long training field, a very high throughput long training field and another type of training field.

10. The apparatus of claim 7 , wherein the second signal is a data field of a WiFi signal.

11. The apparatus of claim 7 , wherein tracking the communication channel comprises updating the determined CSI when the communication channel changes.

12. The apparatus of claim 11 , wherein recently updated values of CSI are provided a higher weighting when updating the determined CSI when the communication channel changes.