Method, apparatus and system for estimating channels
A method, an apparatus and a system for estimating channels are disclosed. A method for estimating channels includes: receiving downlink signals inclusive of reference signals from two or more Access Points (APs), where the relative frequency shift between reference signals sent by different APs is zero; and performing channel estimation according to the reference signals. Another method for estimating channels includes: receiving downlink signals inclusive of reference signals from two or more APs, where for a first AP and a second AP among the two or more APs, a specific time-frequency lattice in the downlink signals sent by the first AP includes no data signal, and the specific time-frequency lattice corresponds to a time-frequency lattice utilized by the second AP to send a reference signal; and performing channel estimation according to the reference signals. The technical solution disclosed herein eliminates the interference between the reference signal and the data signal, enables the UE to estimate the channel value between the UE and the cooperative APs accurately, and improves the UE performance.
1. A channel estimation method, comprising:
receiving, by a User Equipment (UE), downlink signals inclusive of reference signals from two or more Access Points (APs), wherein a specific time-frequency lattice in the downlink signals sent by a first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to a time-frequency lattice utilized by a second AP among the two or more APs to send a reference signal; and
performing, by the UE, channel estimation according to the reference signals.
2. The channel estimation method according to claim 1 , wherein:
the reference signals are dedicated reference signals and/or common reference signals.
3. The channel estimation method according to claim 1 , wherein:
the reference signals are dedicated reference signals, the downlink signals further comprise common reference signals, and a relative frequency shift between the common reference signals sent by different APs is zero.
4. The channel estimation method according to claim 1 , wherein:
the reference signals are dedicated reference signals, and the method further comprises:
regarding data signals in the downlink signals as interference signals to perform channel estimation;
estimating the data signals according to a result of the channel estimation; and
eliminating the data signals in the downlink signals according to a result of estimating the data signals, and performing channel estimation.
5. The channel estimation method according to claim 1 , wherein:
the reference signals are dedicated reference signals, and no common reference signal is comprised in any data channel symbol domain except a preset symbol domain in the downlink signals.
6. The channel estimation method according to claim 1 , wherein:
the reference signals are common reference signals, and the specific time-frequency lattice is located in a data channel symbol domain of the downlink signals.
7. A channel estimation apparatus, comprising:
a receiver, configured to receive downlink signals inclusive of reference signals from two or more Access Points (APs), wherein: a specific time-frequency lattice in the downlink signals sent by a first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to a time-frequency lattice utilized by a second AP among the two or more APs to send a reference signal; and
an estimating unit, configured to perform channel estimation according to the reference signals.
8. The channel estimation apparatus according to claim 7 , wherein the reference signals are dedicated reference signals;
the estimating unit further comprises:
a first estimating unit, configured to regard data signals in the downlink signals as interference signals to perform channel estimation;
a second estimating unit, configured to estimate the data signals according to a result of the channel estimation; and
a third estimating unit, configured to eliminate the data signals in the downlink signals according to a result of estimating the data signals, and perform channel estimation.
9. The channel estimation apparatus according to claim 8 , wherein:
the receiving unit is configured to receive downlink signals inclusive of common reference signals from the two or more APs, and the specific time-frequency lattice in the downlink signals sent by the first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP among the two or more APs to send the common reference signal; wherein the specific time-frequency lattice is located in a data channel symbol domain of the downlink signals.
10. The channel estimation apparatus according to claim 8 , wherein:
the receiver is configured to receive downlink signals inclusive of dedicated reference signals from the two or more APs, and the specific time-frequency lattice in the downlink signals sent by the first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP among the two or more APs to send the dedicated reference signal; wherein: the downlink signals further comprise common reference signals, and the relative frequency shift between the common reference signals sent by different APs is zero.
11. The channel estimation apparatus according to claim 7 , wherein:
the receiver is configured to receive downlink signals inclusive of dedicated reference signals from the two or more APs, and the specific time-frequency lattice in the downlink signals sent by the first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP among the two or more APs to send the dedicated reference signal; wherein: the downlink signals further comprise common reference signals, and the relative frequency shift between the common reference signals sent by different APs is zero.
12. The channel estimation apparatus according to claim 7 , wherein: the receiver is configured to receive downlink signals inclusive of common reference signals from the two or more APs, and the specific time-frequency lattice in the downlink signals sent by the first AP among the two or more APs comprises no signal, and the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP among the two or more APs to send the common reference signal; wherein the specific time-frequency lattice is located in a data channel symbol domain of the downlink signals.
13. A channel estimation system, comprising: a first Access Points (AP) and a second AP, wherein:
the first AP and the second AP are configured to send downlink signals inclusive of reference signals to a User Equipment (UE), a specific time-frequency lattice in the downlink signals sent by the first AP does not comprise signal, and the specific time-frequency lattice corresponds to a time-frequency lattice utilized by the second AP to send a reference signal.
14. The system according to claim 13 , wherein
the first AP and the second AP are configured to send downlink signals inclusive of dedicated reference signals and common reference signals, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise signal, the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP to send the dedicated reference signal; and the relative frequency shift between the common reference signals sent by the first AP and the second AP is zero.
15. The system according to claim 13 , wherein
the first AP and the second AP are configured to send downlink signals inclusive of common reference signals, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise signal, and the specific time-frequency lattice corresponds to the time-frequency lattice utilized by the second AP to send the common reference signal; wherein the specific time-frequency lattice is located in a data channel symbol domain of the downlink signals.