Searching method for maximum-likelihood (ML) detection

• US 7,920,656 B2
• Filed: 12/16/2005
• Issued: 04/05/2011
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Realtek Semiconductor Corp.
• Original Assignee: Realtek Semiconductor Corp.
• Inventors: Yu, Jiun-Hung
• Primary Examiner(s): Liu; Shuwang
• Assistant Examiner(s): Yu; Lihong
• Application Number:
  US11/306,110
• Publication Number:
  US 20060198470A1
• Time in Patent Office: 1,936 Days
• Field of Search: 375/341
• US Class Current: 375/341
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/06 using space diversity

Abstract

The present invention relates to a method for searching a solution point of maximum-likelihood detection. The solution point locates at a symbol constellation. The method includes the following steps: determining a central point and a norm by a zero-forcing detection method; determining a searching range according to the central point and the norm; determining at least one qualified solution point according to the searching range; and determining the solution point of maximum-likelihood detection from the qualified solution points.

Claims

1. A method for identifying a plurality of symbols transmitted by a transmitter of a wireless communication system according to a plurality of signals received by a receiver of the wireless communication system, the method being implemented in the receiver and for searching a solution point of maximum-likelihood (ML) detection according to the plurality of signals and thereby identifying the plurality of symbols, the method comprising:

utilizing a zero-forcing detection to process the plurality of signals and thereby provide a central point;

slicing the central point to provide a solution point for the zero-forcing detection;

calculating a radius C_ZF for the ML detection, the radius C_ZF being the distance between the central point and the solution point for the zero-forcing detection, which consequently results in the radius C_ZF longer than or equal to a distance C_ML from the central point to a solution point of the ML detection;

determining a searching range of the ML detection according to the central point and the radius C_ZF;

determining one or more qualified solution points according to the plurality of signals and the searching range; and

determining one of the one or more qualified solution points as the solution point of the ML detection.

2. The method of claim 1, wherein the searching range is a sphere, the central point and the radius C_ZF define the sphere, and the ML detection utilizes a sphere decoding method.

3. The method of claim 1, wherein the searching range is a rectangle.

4. The method of claim 3, wherein the central point is a geometric center of the rectangle and both length and width of the rectangle are not shorter than double the radius C_ZF.

5. The method of claim 1, wherein the searching range is a square.

6. The method of claim 5, wherein the central point is a geometric center of the square and each side length of the square is not shorter than double the radius C_ZF.

7. The method of claim 1, wherein the receiver of the wireless communication system has a plurality of antennas for receiving the signals.

8. The method of claim 1, wherein the slicing comprises rounding each coordinate of the central point to a nearest integer.

9. The method of claim 1, wherein the solution point of the zero-forcing detection is a point that is on a zero-forcing lattice.

10. The method of claim 9, wherein the central point is a point that is not on the zero-forcing lattice.

11. The method of claim 1, wherein the central point is an intermediate unrounded result of zero-forcing detection.

12. A wireless communication receiver, comprising:

logic that utilizes a zero-forcing detection to process a plurality of signals received from a transmitter and thereby provide a central point;

logic that slices the central point to provide a solution point for the zero-forcing detection;

logic that calculates a radius C_ZF for a maximum-likelihood (ML) detection, the radius C_ZF being the distance between the central point and the solution point for the zero-forcing detection;

logic that determines a searching range of the ML detection according to the central point and the radius C_ZF; and

logic that determines at least one qualified solution point for the ML detection according to the plurality of signals and the searching range.