Optimization of paging cost in mobile switching system using a genetic optimization method

• US 6,181,945 B1
• Filed: 12/10/1997
• Issued: 01/30/2001
• Est. Priority Date: 01/27/1997
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Lee, Hee C.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US08/988,048
• Time in Patent Office: 1,147 Days
• Field of Search: 455/458, 455/456, 455/38.1, 455/432, 455/435, 455/502
• US Class Current: 455/445
• CPC Class Codes: H04W 68/04 multi-step notification using statistical or historical mobility data

Abstract

The invention overcomes the inefficient conventional mobile paging methods that cause a bottleneck in the FOCC due to constraints of both the bandwidth and the limited number of radio frequency channels in mobile telecommunication systems. This is accomplished by first determining the mobility pattern of each mobile station during a given sampling period. Then the probability that the mobile station will be located within each cell in the network is determined. From the cells having non-zero probabilities, at least two paging zones are defined using a genetic optimization method which converges on paging zones which produce a minimum paging cost which correspondingly results in minimum utilization of the FOCC.

Claims

1. A method for optimizing paging of a mobile telecommunications device in a cellular telecommunications network comprising the steps of:

a) determining the probability that the mobile device is located physically within the geographic area served by each physical cell in the network during a given sampling period;

b) creating a first generation of paging zone plans consisting of at least two randomly created paging zone plans, each paging zone plan consisting of cells where the probability that the mobile unit is located therein is non-zero, and calculating the paging cost for each first generation paging zone plan;

c) performing a genetic operation on the two paging zone plans having the lowest paging cost in the first generation of paging zone plans to produce two resulting paging zone plans and substituting the resulting paging zone plans for the paging zone plans in the first generation of paging zone plans having the two highest paging costs;

d) repeating step c an arbitrary number of times until a further generation of paging zone plans has been produced; and

,

e) repeating steps c and d with the further generation of paging zone plans resulting from step d being substituted for the first generation of paging zone plans in step c until the lowest cost paging zone plan for one generation of paging zone plans is not greater than the lowest cost paging zone plan for the subsequent generation.

2. The method of claim 1 additionally including the step of paging the mobile device in the lowest cost paging zones defined in step e.

3. The method of claim 1 wherein the number of paging zones is in the range of between 2 and 4.

4. The method of claim 1 wherein the genetic operation comprises either a cross-over or a reproduction operation.

5. The method of claim 4 wherein a cross-over operation occurs about 70% of the time and a reproduction operation occurs about 30% of the time.

6. A method for optimizing paging of a mobile telecommunications device in a cellular telecommunications network comprising the steps of:

a.) determining the probability that the mobile device is located physically within the geographic area served by each physical cell in the network during a given sampling period;

b.) using the probability that the mobile device is located within each physical cell in the network in a genetic optimization process to define a plurality of paging zones for locating the mobile device among only those cells where the probability that the mobile device is located therein is non-zero, said genetic optimization process including the steps of;

creating a first generation including a plurality of randomly created paging zone plans, each paging zone plan of said first generation including a plurality of paging zones;

calculating the paging cost for each paging zone plan of said first generation;

performing a genetic operation on the two paging zone plans of said first generation having the lowest paging cost to produce two resulting paging zone plans; and

,

substituting said resulting paging zone plans for the two paging zone plans of said first generation having the highest paging cost.

7. The method of claim 6 wherein the genetic operation comprises either a cross-over or a reproduction operation.

8. The method of claim 6 wherein a cross-over operation occurs about 70% of the time and a reproduction operation occurs about 30% of the time.

9. The method of claim 6 includes repeating said performing and substituting steps of claim 6 for a plurality of times to change a first generation paging zone plans into the second generation paging zone plans.