Wireless apparatus and channel prediction method
A wireless apparatus includes a channel estimation part that acquires an estimated impulse response which is an estimate value of an impulse response of a channel between a wireless terminal and the wireless apparatus, a tap location error detection part that detects a tap location error between estimated impulse responses at different time points out of the estimated impulse responses, and a channel prediction part that calculates a predicted impulse response which is an impulse response of the channel at a future time point by using the estimated impulse responses and the tap location error.
1. A wireless apparatus, comprising:
a channel estimation part that acquires an estimated impulse response which is an estimate value of an impulse response of a channel between a wireless terminal and the wireless apparatus;
a tap location error detection part that detects a tap location error between estimated impulse responses acquired at different time points; and
a channel prediction part that calculates a predicted impulse response which is an impulse response of the channel at a future time point by using the estimated impulse responses and the tap location error.
2. The wireless apparatus according to claim 1 , further comprising
a plurality of antennas,
wherein the channel estimation part estimates, as the impulse response, an impulse response of a channel between the wireless terminal and an individual one of the plurality of antennas.
3. The wireless apparatus according to claim 1 , further comprising
a plurality of antennas,
wherein the channel estimation part calculates, as the impulse response, an impulse response corresponding to a beam by using a plurality of impulse responses of a plurality of channels between the wireless terminal and individual ones of the plurality of antennas and a weight matrix.
4. The wireless apparatus according to claim 1 , wherein the tap location error detection part detects the tap location error based on a magnitude of the estimated impulse response at each tap.
5. The wireless apparatus according to claim 1 , wherein the tap location error detection part detects the tap location error based on a correlation between the estimated impulse responses at different time points.
6. The wireless apparatus according to claim 1 , wherein the channel prediction part adjusts a tap location of the estimated impulse response based on the tap location error and calculates the predicted impulse response.
7. The wireless apparatus according to claim 1 , wherein the channel prediction part predicts an amplitude and a phase of the predicted impulse response.
8. The wireless apparatus according to claim 1 , wherein the channel prediction part sets 0 as a value of the predicted impulse response for a tap at which a magnitude of the estimated impulse response is less than a predetermined threshold value, without calculating a predicted impulse response for the tap.
9. The wireless apparatus according to claim 1 , wherein the channel prediction part sets 0 as a value of the predicted impulse response for a tap at which a magnitude of the predicated impulse response is less than a predetermined threshold value.
10. The wireless apparatus according to claim 1 , wherein the channel prediction part performs cyclic shift on locations of taps of the estimated impulse response at a first time point by the tap location error between the estimated impulse response at the first time point and the estimated impulse response at a second time point, and
obtains a value at a tap of the predicted impulse response, by performing linear or not less than quadratic extrapolation on at least a value at the tap of the estimated impulse response at the second time point and a value at a corresponding tap of the estimated impulse response cyclic shifted.
11. The wireless apparatus according to claim 1 , wherein the channel prediction part performs weighted synthesis of a plurality of estimated impulse responses at a plurality of time points to obtain the predicted impulse response at the future time point, each of the plurality of estimated impulse responses obtained by performing cyclic shift on locations of taps of the estimated impulse response at each time point by the tap location error between the estimated impulse response at the each time point and the estimated impulse response at a reference time point.
12. A channel prediction method, comprising:
acquiring an estimated impulse response which is an estimate value of an impulse response of a channel between a wireless terminal and a wireless apparatus;
detecting a tap location error between estimated impulse responses acquired at different time points; and
calculating a predicted impulse response which is an impulse response of the channel at a future time point by using the estimated impulse responses and the tap location error.
13. The channel prediction method according to claim 12 , comprising
estimating, as the impulse response, an impulse response of a channel between the wireless terminal and an individual one of a plurality of antennas included in the wireless apparatus.
14. The channel prediction method according to claim 12 , comprising
calculating, as the impulse response, an impulse response corresponding to a beam by using a plurality of impulse responses of a plurality of channels between the wireless terminal and individual ones of the plurality of antennas and a weight matrix.
15. The channel prediction method according to claim 12 , comprising
detecting the tap location error based on a magnitude of the estimated impulse response at each tap.
16. The channel prediction method according to claim 12 , comprising
detecting the tap location error based on a correlation between the estimated impulse responses at different time points.
17. The channel prediction method according to claim 12 , comprising
adjusting a tap location of the estimated impulse response based on the tap location error to calculate a predicted impulse response.
18. The channel prediction method according to claim 12 , comprising
predicting an amplitude and a phase of the predicted impulse response.
19. The channel prediction method according to claim 12 , comprising
setting 0 as a value of the predicted impulse response for a tap at which a magnitude of the estimated impulse response is less than a predetermined threshold value without calculating a predicted impulse response for the tap.
20. A non-transitory computer readable medium storing a program causing a processor included in a wireless apparatus to execute processing comprising:
acquiring an estimated impulse response which is an estimate value of an impulse response of a channel between a wireless terminal and the wireless apparatus;
detecting a tap location error between estimated impulse responses acquired at different time points; and
a predicted impulse response which is an impulse response of the channel at a future time point by using the estimated impulse responses and the tap location error.