Apparatus of maximum likelihood signal detection

Abstract

An apparatus for maximum likelihood signal detection comprises a reference data unit, a branch metric unit, an add-compare-select unit, a path metric unit and a path memory, and is used for detecting maximum likelihood signal. The reference information unit, the branch metric unit, the add-compare-select unit or the path metric unit can further comprise a multiplexer to removing unnecessary paths according to a control signal. The control signal is adjusted according to channel response, coding constraint or channel memory length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The various objects and advantages of the invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which:

FIG. 1 is a block diagram of a conventional Viterbit decoder applied in a partial response maximum likelihood device;

FIG. 2 shows trellis diagrams of the invention with a channel memory length n=3 and a coding constraint d=0, 1, 2, and ½, respectively;

FIG. 3 shows trellis diagrams of the invention with a channel memory length n=4 and a coding constraint d=0, 1, 2, and ½, respectively;

FIG. 4 shows trellis diagrams of the invention with a channel memory length n=3, 4 and ¾ and a coding constraint d=½, respectively;

FIG. 5 shows a trellis diagram of the invention with a channel memory length n=¾ and a coding constraint d=½;

FIG. 6A is a system block diagram of an apparatus for maximum likelihood signal detection according to a first embodiment of the invention;

FIG. 6B is a more detailed system block diagram for an apparatus of maximum likelihood signal detection according to the first embodiment of the invention;

FIG. 7 is a system block diagram of an apparatus for maximum likelihood signal detection according to a second embodiment of the invention;

FIG. 8 is a system block diagram of an apparatus for maximum likelihood signal detection according to a third embodiment of the invention;

FIG. 9A is a system block diagram of an apparatus for maximum likelihood signal detection according to a fourth embodiment of the invention;

FIG. 9B is another system block diagram of an apparatus for maximum likelihood signal detection according to the fourth embodiment of the invention;

FIGS. 10A and 10B are trellis diagrams of the invention with a channel memory length n=3, a coding constraint d=½ and a number of read bit M=2;

FIGS. 11A and 11B are trellis diagrams of the invention with a channel memory length n=4, a coding constraint d=½ and a number of read bit M=2;

FIG. 12 is a trellis diagram of the invention with a channel memory length n=¾, a coding constraint d=½ and a number of read bit M=2;

FIG. 13 is another trellis diagram of the invention with a channel memory length n=¾, a coding constraint d=½ and a number of read bit M=2; and

FIG. 14 is yet another trellis diagram of the invention with a channel memory length n=¾, a coding constraint d=½ and a number of read bit M=2.

Claims

1. An apparatus for maximum likelihood signal detection comprising: a reference information unit for generating a reference signal;a branch metric unit for receiving an input signal and the reference signal to generate a first branch metric, wherein the branch metric unit comprises: a branch meter for generating a second branch metric according to the input signal and the reference signal; anda multiplexer for outputting the second branch metric or a predetermined branch metric to be the first branch metric according to a control signal;an add-compare-select unit for receiving the first branch metric and performing addition, comparison and selection actions to generate a survival path metric and a determination result signal;a path metric unit for storing the survival path metric; anda path memory for storing a path data according to the determination result signal.

2. The apparatus for maximum likelihood signal detection as claimed in claim 1, wherein the control signal is adjusted according to the corresponding condition of the input data, wherein the corresponding condition comprises channel response, coding constraint or channel memory length of the input signal.

3. The apparatus for maximum likelihood signal detection as claimed in claim 2, wherein the coding constraint is equal to 1 or 2.

4. The apparatus for maximum likelihood signal detection as claimed in claim 2, wherein the channel memory length is equal to 3 or 4.

5. An apparatus for maximum likelihood signal detection comprising: a reference information unit for generating a first reference signal, wherein the reference information unit comprises:a reference signal generator for generating a second reference signal according to an input signal; anda multiplexer for outputting the second reference signal or a predetermined reference signal to be the first reference signal according to a control signal;a branch metric unit for receiving the input signal and the first reference signal to generate a branch metric;an add-compare-select unit for receiving the branch metric and performing addition, comparison and selection actions to generate a survival path metric and a determination result signal;a path metric unit for storing the survival path metric; anda path memory for storing a path data according to the determination result signal.

6. The apparatus for maximum likelihood signal detection as claimed in claim 5, wherein the control signal is adjusted according to the corresponding condition of the input data, wherein the corresponding condition comprises channel response, coding constraint or channel memory length of the input signal.

7. The apparatus for maximum likelihood signal detection as claimed in claim 6, wherein the coding constraint is equal to 1 or 2.

8. The apparatus for maximum likelihood signal detection as claimed in claim 6, wherein the channel memory length is equal to 3 or 4.

9. An apparatus for maximum likelihood signal detection comprising: a reference information unit for generating a reference signal;a branch metric unit for receiving an input signal and the reference signal to generate a first branch metric;an add-compare-select unit for receiving a second branch metric and performs addition, comparison and selection actions to generate a survival path metric and a determination result signal, wherein the add-compare-select unit further comprises: a multiplexer for outputting the first branch metric or a predetermined input value to be the second branch metric according to a control signal;a path metric unit for storing the survival path metric; anda path memory for storing a path data according to the determination result signal.

10. The apparatus for maximum likelihood signal detection as claimed in claim 9, wherein the control signal is adjusted according to the corresponding condition of the input data, wherein the corresponding condition comprises channel response, coding constraint or channel memory length of the input signal.

11. The apparatus for maximum likelihood signal detection as claimed in claim 10, wherein the channel memory length is equal to 3 or 4.

12. The apparatus for maximum likelihood signal detection as claimed in claim 10, wherein the coding constraint is equal to 1 or 2.

13. An apparatus for maximum likelihood signal detection comprising: a reference information unit for generating a reference signal;a branch metric unit for receiving an input signal and the reference signal to generate a branch metric;an add-compare-select unit for receiving the branch metric and performing addition, comparison and selection actions to generate a survival path metric and a determination result signal;a path metric unit for storing the survival path metric, wherein the path metric unit comprises: a path metric memory storing the survival path metric; andan multiplexer outputting the stored survival path metric or a predetermined path metric to the add-compare-select unit according to a control signal; anda path memory for storing a path data according to the determination result signal.

14. The apparatus for maximum likelihood signal detection as claimed in claim 13, wherein the control signal is adjusted according to the corresponding condition of the input data, wherein the corresponding condition comprises channel response, coding constraint or channel memory length of the input signal.

15. The apparatus for maximum likelihood signal detection as claimed in claim 14, wherein the coding constraint is equal to 1 or 2.

16. The apparatus for maximum likelihood signal detection as claimed in claim 14, wherein the channel memory length is equal to 3 or 4.

17. The apparatus for maximum likelihood signal detection as claimed in claim 14, wherein the maximum likelihood detection device adjusts the control signal according to a trellis diagram with a read bit M=2.