METHOD, APPARATUS AND SYSTEM FOR ESTIMATING CHANNELS

• US 20110312356A1
• Filed: 09/09/2011
• Published: 12/22/2011
• Est. Priority Date: 11/12/2008
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: WAN, Lei, CHENG, Xingqing, ZHOU, Mingyu, ZHAO, Yajun
• Granted Patent: US 8,112,105 B2
• Time in Patent Office: Days
• US Class Current: 455/501
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/29 between an access point and the access point controlling device

Abstract

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 does not include 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.

Claims

1. A channel estimation method, comprising:

receiving, by a User Equipment (UE), downlink signals inclusive of reference signals from a first Access Points (AP) and a second AP, wherein a specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data signal, the specific time-frequency lattice corresponds to a time-frequency lattice utilized by the second AP to send a reference signal, and time-frequency lattices utilized by the first AP and the second AP to send reference signals are different; 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 common reference signals.

3. The channel estimation method according to claim 1, wherein:

the reference signals are common reference signals.

4. The channel estimation method according to claim 3, wherein:

the specific time-frequency lattice is located in a data channel symbol domain of the downlink signals.

5. The channel estimation method according to claim 1, wherein:

the reference signals are dedicated reference signals.

6. The channel estimation method according to claim 5, wherein:

the downlink signals further comprise common reference signals, and a relative frequency shift between the common reference signals sent by the first AP and the second AP is zero.

7. The channel estimation method according to claim 5, wherein:

the method further comprises;

performing channel estimation by regarding data signals in the downlink signals as interference signals;

estimating the data signals according to a result of the channel estimation;

eliminating the data signals in the downlink signals according to a result of estimating the data signals; and

performing channel estimation.

8. The channel estimation method according to claim 5, wherein:

no common reference signal is comprised in any data channel symbol domain except a preset symbol domain in the downlink signals.

9. A channel estimation apparatus, comprising:

a receiver, configured to receive downlink signals inclusive of reference signals from a first Access Points (AP) and a second AP, wherein;

a specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data signal, the specific time-frequency lattice corresponds to a time-frequency lattice utilized by the second AP to send a reference signal, and time-frequency lattices utilized by the first AP and the second AP to send reference signals are different; and

an estimating unit, configured to perform channel estimation according to the reference signals.

10. The channel estimation apparatus according to claim 9, wherein the reference signals are dedicated reference signals;

the estimating unit further comprises;

a first estimating sub-unit, configured to perform channel estimation by regarding data signals in the downlink signals as interference signals;

a second estimating sub-unit, configured to estimate the data signals according to a result of the channel estimation; and

a third estimating sub-unit, configured to eliminate the data signals in the downlink signals according to a result of estimating the data signals, and perform channel estimation.

11. The channel estimation apparatus according to claim 9, wherein:

the receiver is configured to receive downlink signals from the first AP and the second AP, the downlink signals include dedicated reference signals and common reference signals, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data 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.

12. The channel estimation apparatus according to claim 9, wherein:

the receiver is configured to receive downlink signals inclusive of common reference signals from the first AP and the second AP, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data 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.

13. The channel estimation apparatus according to claim 10, wherein:

the receiver is configured to receive downlink signals from the first AP and the second AP, the downlink signals include dedicated reference signals and common reference signals, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data 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.

14. The channel estimation apparatus according to claim 10, wherein:

the receiver is configured to receive downlink signals inclusive of common reference signals from the first AP and the second AP, the specific time-frequency lattice in the downlink signals sent by the first AP does not comprise data 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.

15. 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 data signal, the specific time-frequency lattice corresponds to a time-frequency lattice utilized by the second AP to send a reference signal, and time-frequency lattices utilized by the first AP and the second AP to send reference signals are different.

16. The system according to claim 15, 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 data 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.

17. The system according to claim 15, 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 data 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.