Viterbi decoder with reduced metric computation
First Claim
1. A method for determining a plurality of branch metrics at a symbol instant that are comprised of autocorrelation terms and cross correlation terms, including the steps of generating components of the autocorrelation terms, storing the components of the autocorrelation terms, generating components of the cross correlation terms, storing the components of the cross correlation terms, characterized by:
- selecting predetermined ones of the autocorrelation components and the cross correlation components, andcombining the selected autocorrelation components and cross correlation components in a predetermined manner to produce a branch metric.
5 Assignments
0 Petitions
Accused Products
Abstract
There is disclosed a method and apparatus for computing branch metrics that are combinations of autocorrelation and cross correlation terms are constructed by first calculating and storing components of the autocorrelation and cross correlation terms at a symbol instant. Once calculated and stored, predetermined ones of the autocorrelation components and the cross correlation components are selected. The selected autocorrelation components and cross correlation components, or their inverse as predetermined, are combined to produce a branch metric. Other predetermined combinations of the stored components of autocorrelation and cross correlation terms, or their inverse, are combined to produce other branch metrics at the same symbol instant. All branch metrics associated with the symbol instant can be calculated in this manner. The components of the autocorrelation terms and cross correlation terms associated with the next symbol instant are calculated and stored, and the process of generating the branch metrics repeated.
-
Citations
21 Claims
-
1. A method for determining a plurality of branch metrics at a symbol instant that are comprised of autocorrelation terms and cross correlation terms, including the steps of generating components of the autocorrelation terms, storing the components of the autocorrelation terms, generating components of the cross correlation terms, storing the components of the cross correlation terms, characterized by:
-
selecting predetermined ones of the autocorrelation components and the cross correlation components, and combining the selected autocorrelation components and cross correlation components in a predetermined manner to produce a branch metric. - View Dependent Claims (2)
-
-
3. An integrated circuit including a branch metric calculation circuit, comprising:
-
a circuit for generating components of autocorrelation terms; at least one register for receiving and storing components of the autocorrelation terms; a circuit for generating components of cross correlation terms; at least one register for receiving and storing components of the cross correlation terms; a selection circuit for selecting predetermined ones of the autocorrelation components and the cross correlation components stored in said at least one registers; a selective inverter circuit for selectively inverting predetermined ones of the selected auto correlation components and cross correlation components; and a combining circuit for receiving the selected auto correlation components and cross correlation components and for combining the selected autocorrelation components and cross correlation components to produce a branch metric. - View Dependent Claims (4, 5, 6, 7, 8)
-
-
9. An integrated circuit comprising:
-
a circuit for generating components of autocorrelation terms; a circuit for generating components of cross correlation terms; a circuit for combining autocorrelation components and cross correlation components; at least two registers for receiving and storing components of the autocorrelation terms; at least two registers for receiving and storing components of the cross correlation terms; a selection circuit for selecting predetermined ones of the autocorrelation components and the cross correlation components stored in said at least two registers; a selective circuit for selectively inverting predetermined ones of the selected auto correlation components and cross correlation components; and a combining circuit for receiving the selected auto correlation components and cross correlation components and for combining the selected autocorrelation components and cross correlation components to produce a branch metric. - View Dependent Claims (10, 11, 12, 13, 14)
-
-
15. A receiver, comprising:
-
a circuit for generating components of autocorrelation terms; at least one register for receiving and storing components of the autocorrelation terms; a circuit for generating components of cross correlation terms; at least one register for receiving and storing components of the cross correlation terms; a selection circuit for selecting predetermined ones of the autocorrelation components and the cross correlation components stored in said at least one registers, a selective inverter circuit for selectively inverting predetermined ones of the selected auto correlation components and cross correlation components; and a combining circuit for receiving the selected auto correlation components and cross correlation components and for combining the selected autocorrelation components and cross correlation components to produce a branch metric. - View Dependent Claims (16, 17, 18, 19, 20, 21)
-
Specification