Granted Patent B2

US 7,693,422 · App. 10/952,015 · Granted Apr 6, 2010

Abstract

Claims (60)

1. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration based on the at least one constraint further comprises traversing element locations from a source to a destination such that increasingly longer solutions are computed.

2. The method of claim 1 , wherein, at each element location H j , optimal solutions are computed from H 1 to H j under two cases: (a) assuming an amplifier is placed at H j ; and (b) assuming a splice is placed at H j .

3. The method of claim 2 , wherein, under case (a), a configuration is derived by considering all solutions up to H j-1 with and without amplifiers at H j-1 and adding an amplifier at H j , and selecting the least-cost result.

4. The method of claim 2 , wherein, under case (b), let H k be the last location before H j that has an amplifier, and extend solutions up to H j-1 with and without amplifiers at H j-1 .

5. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration based on the at least one constraint further comprises generating solutions for element locations H 1 . . . H j from solutions for H 1 . . . H j-1 knowing the nearest extra loss span having a loss up to the given second maximum signal loss from H j-1 in the latter.

6. The method of claim 5 , when the nearest extra loss span is a given number of spans away, allow traversal of a longer distance in the span containing H j .

7. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining constraints on the design of the optical transmission system, wherein the constraints comprise: (i) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (ii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration based on constraint (ii) further comprises:

computing all possible configurations having m−1 spans that are valid under constraint (i) starting from every element location and all the configurations having m−1 or less spans starting from location H 1 ; and

using each such configuration C i,j equal to H i . . . H j , computing an optimal configuration from locations H 1 . . . H j that includes C i,j , for increasing values of i;

wherein the overall solution results when C i,j includes the destination location.

8. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises one of: (i) a signal loss in a span should not exceed a given maximum signal loss; (ii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; (iii) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (iv) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration is bi-directionally solved when span losses are identical in both directions by computing a solution for the uni-directional case and applying the resulting solution to the reverse direction by shifting elements by one element location.

9. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises one of: (i) a signal loss in a span should not exceed a given maximum signal loss; (ii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; (iii) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (iv) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration is bi-directionally solved when span losses are not identical in both directions by at least one of: taking the distance in both directions into account; letting a cost of an element c i,j be the cost of the elements for both d i,j and d j,i ; computing extra loss spans in both directions; and, at the end of the computation, shifting the elements in the reverse direction by one element location.

10. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises one of: (i) a signal loss in a span should not exceed a given maximum signal loss; (ii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; (iii) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (iv) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration further comprises ignoring computed configurations that place a splice at an optical add-drop multiplexer location.

11. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises one of: (i) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; (ii) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (iii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration further comprises constructing a new element location.

12. A method of designing an optical transmission system, the method comprising the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises one of: (i) a signal loss in a span should not exceed a given maximum signal loss; (ii) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; (iii) a signal loss in a span should not exceed a given first maximum signal loss and a span should be longer than a given minimum span length, however, at most one in m contiguous spans can have a loss up to a given second maximum signal loss, wherein the second maximum signal loss is greater than the first maximum signal loss; and (iv) a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length, and an average span loss of any m consecutive spans should not exceed a given average loss, wherein the average loss is less than the given maximum signal loss; and

computing via a processor a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration further comprises constructing a new element location; and

wherein the step of constructing a new element location further comprises placing hypothetical locations at d kilometer intervals starting from every existing location and, at the end of the computation, eliminating those locations containing splices.

13. Apparatus for designing an optical transmission system, comprising:

a memory; and

at least one processor coupled to the memory and operative to:

obtain a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtain at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; and

compute a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the operation of computing the least-cost configuration based on the at least one constraint further comprises traversing element locations from a source to a destination such that increasingly longer solutions are computed.

14. An article of manufacture for designing an optical transmission system, comprising a computer readable storage medium containing one or more programs which when executed implement the steps of:

obtaining a set of one or more demands and a set of optical transmission system elements wherein elements may be consecutively coupled via a span;

obtaining at least one constraint on the design of the optical transmission system, wherein the at least one constraint comprises a signal loss in a span should not exceed a given maximum signal loss and a span should be longer than a given minimum span length; and

computing a least-cost configuration for the optical transmission system based on at least a portion of the set of one or more demands and the set of one or more optical transmission system elements such that the at least one constraint is satisfied;

wherein the step of computing the least-cost configuration based on the at least one constraint further comprises traversing element locations from a source to a destination such that increasingly longer solutions are computed.

Assignments (9)