Channel estimation apparatus and method for interference cancellation in mobile communication system

• US 20070242782A1
• Filed: 03/13/2007
• Published: 10/18/2007
• Est. Priority Date: 03/13/2006
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Han, Ki-Young, Yoon, Soon-Young, Hwang, Sung-Soo, Moon, June, Hwang, Keun-Chul, Lee, Joo-Hyun
• Application Number:
  US11/717,526
• Publication Number:
  US 20070242782A1
• Time in Patent Office: Days
• US Class Current: 375/343
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/025 using least-mean-square [LMS] method
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

Channel estimation apparatus and method for interference cancellation in a mobile communication system are provided. The channel estimation method includes detecting a preamble from a received signal and estimating a primary channel using the detected preamble; calculating a short-term correlation matrix using the primary channel; and estimating a secondary channel using the calculated short-term correlation matrix according to a certain channel estimation scheme.

Claims

1. A channel estimation method in a mobile communication system, comprising:

detecting a preamble from a received signal and estimating a primary channel using the detected preamble;

calculating a short-term correlation matrix using the primary channel; and

estimating a secondary channel using the calculated short-term correlation matrix according to a channel estimation scheme.

2. The channel estimation method of claim 1, wherein the channel estimation scheme is a short-term Minimum Mean Squared Error (MMSE) channel estimation scheme.

3. The channel estimation method of claim 1, wherein the primary channel estimating step comprises:

estimating a corresponding channel using a preamble at subcarriers allocated a preamble, and estimating a channel at subcarriers not allocated a preamble by interpolating a channel of subcarriers allocated an adjacent preamble.

4. The channel estimation method of claim 3, wherein the channel of a serving Base Station (BS) at subcarriers not allocated the preamble is estimated based on

${\hat{h}}_s$

( n m ) = ( n - n m ) ⁢

h ^ s ⁡

( p - 1 ) + n m ⁢

h ^ s ⁡

( p ) n

where n denotes a number of subcarriers not allocated a preamble between adjacent subcarriers allocated a preamble, ĥ

_s(nm) denotes a channel of the serving BS at a n_m-th subcarrier, p denotes a number of subcarriers allocated a preamble, and h_s(p) denotes a channel of the serving BS estimated at the p-ary subcarriers allocated a preamble.

5. The channel estimation method of claim 4, wherein the channel of an interfering BS at subcarriers not allocated a preamble is estimated in the same manner as the channel of the serving BS.

6. The channel estimation method of claim 1, wherein elements of the short-term correlation matrix are estimated based on

$\begin{array}{c}E\end{array}$

{ 

h s 

2 } ≈

1 M ⁢

∑

m = 1 M ⁢



h ^ s ⁡

( m ) 

2 E ⁢

{ 

h i 

2 } ≈

1 M ⁢

∑

m = 1 M ⁢



h ^ i ⁡

( m ) 

2 E ⁢

{ h i ⁢

h s * } * = E ⁢

{ h s ⁢

h i * } ≈

1 M ⁢

∑

m = 1 M ⁢

h ^ s ⁡

( m ) ⁢

 

⁢

h ^ i * ⁡

( m )

where h_s denotes a channel corresponding to the serving BS and h_i denotes a channel corresponding to the i-th interfering BS.

7. The channel estimation method of claim 2, wherein the short-term MMSE channel estimation scheme estimates the channel based on

G=(X^HX+σ

²R_h<sup>−

1</sup>)<sup>−

1</sup>X^H

where G denotes an MMSE weight matrix and R_h denotes the correlation matrix.

8. A channel estimation apparatus in a mobile communication system, comprising:

a channel estimator which detects a preamble from a received signal, estimates a primary channel using the detected preamble, calculates a short-term correlation matrix using the primary channel, and estimates a secondary channel using the calculated short-term correlation matrix according to a channel scheme.

9. The channel estimation apparatus of claim 8, further comprising:

an interference cancellation controller for determining whether to cancel interference of the received signal by estimating a Carrier to Interference and Noise Ratio (CINR) of the received signal, and outputs the determination result to the channel estimator and a detector;

the channel estimator for estimating channels of a serving Base Station (BS) and an interfering BS using a preamble of the received signal according to the interference cancellation determination result; and

the detector for canceling the interference of the received signal or compensating for the received signal using the estimated channel values according to the interference cancellation determination result.

10. The channel estimation apparatus of claim 9, wherein the interference cancellation controller determines not to perform the interference cancellation of the received signal when the CINR is greater than a threshold, and determines to perform the interference cancellation of the received signal when the CINR is less than or equal to the threshold.

11. The channel estimation apparatus of claim 9, wherein the channel estimator estimates every channel of signals transmitted from the serving BS and the interfering BS when the interference cancellation controller determines to cancel the interference of the received signal, and the channel estimator estimates only the channel of signals transmitted from the serving BS when the interference cancellation controller determines to compensate for the received signal rather than to cancel the interference.

12. A channel estimation apparatus in a mobile communication system, comprising:

means for detecting a preamble from a received signal and estimating a primary channel using the detected preamble;

means for calculating a short-term correlation matrix using the primary channel; and

means for estimating a secondary channel using the calculated short-term correlation matrix according to a channel estimation scheme.

13. The channel estimation apparatus of claim 12, wherein the channel estimation scheme is a short-term Minimum Mean Squared Error (MMSE) channel estimation scheme.

14. The channel estimation apparatus of claim 12, wherein the function of estimating the primary channel comprises:

estimating a corresponding channel using a preamble at subcarriers allocated a preamble, and estimating a channel at subcarriers not allocated a preamble by interpolating a channel of subcarriers allocated an adjacent preamble.

15. The channel estimation apparatus of claim 14, wherein the channel of a serving Base Station (BS) at subcarriers not allocated the preamble is estimated based on

${\hat{h}}_s$

( n m ) = ( n - n m ) ⁢

h ^ s ⁡

( p - 1 ) + n m ⁢

h ^ s ⁡

( p ) n

where n denotes a number of subcarriers not allocated a preamble between adjacent subcarriers allocated a preamble, ĥ

_s(n_m) denotes a channel of the serving BS at a n_m-th subcarrier, p denotes a number of subcarriers allocated a preamble, and h_s(p) denotes a channel of the serving BS estimated at the p-ary subcarriers allocated a preamble.

16. The channel estimation apparatus of claim 15, wherein the channel of an interfering BS at subcarriers not allocated a preamble is estimated in the same manner as the channel of the serving BS.

17. The channel estimation apparatus of claim 12, wherein the short-term correlation matrix are estimated based on

$\begin{array}{c}E\end{array}$

{ 

h s 

2 } ≈

1 M ⁢

∑

m = 1 M ⁢



h ^ s ⁡

( m ) 

2 E ⁢

{ 

h i 

2 } ≈

1 M ⁢

∑

m = 1 M ⁢



h ^ i ⁡

( m ) 

2 E ⁢

{ h i ⁢

h s * } * = E ⁢

{ h s ⁢

h i * } ≈

1 M ⁢

∑

m = 1 M ⁢

h ^ s ⁡

( m ) ⁢

 

⁢

h ^ i * ⁡

( m )

where h_s denotes a channel corresponding to the serving BS and h_i denotes a channel corresponding to the i-th interfering BS.

18. The channel estimation apparatus of claim 13, wherein the short-term MMSE channel estimation scheme estimates the channel based on

G=(X^HX+σ

²R_h<sup>−

1</sup>)<sup>−

1</sup>X^H

where G denotes an MMSE weight matrix and R_h denotes the correlation matrix.