Method and apparatus for preferred roaming list compression
First Claim
1. A processor implemented method of generating a compressed preferred roaming list (PRL), comprising:
- generating a subnet address by performing a bitwise AND operation on a network identification (ID) and a subnet mask, the subnet address consisting of a plurality of most significant bits and a plurality of least significant bits, the most significant bits of the subnet address representing a common part of a subnet to be factored out;
storing the most significant bits of the subnet address in a subnet table;
storing the least significant bits of the subnet address in a system table;
factoring out at least one set of data common to two or more subnets;
storing said at least one set of data common to said two or more subnets in the subnet table;
generating an indicator for accessing said at least one set of data; and
storing the indicator in the system table.
1 Assignment
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Accused Products
Abstract
Techniques for efficient storage and retrieval of Preferred Roaming Lists are disclosed. In one aspect, PRL entries are stored in two tables. One table contains records that are common to two or more PRL entries. Another table stores any information that is unique to a PRL entry, as well as an indicator of which common record is associated with it. The common record is concatenated with the unique information to generate the uncompressed PRL entry. Various other aspects of the invention are also presented. These aspects have the benefit of reducing the memory requirements for storing a PRL. In addition, time required to download the compressed PRL is reduced.
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Citations
16 Claims
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1. A processor implemented method of generating a compressed preferred roaming list (PRL), comprising:
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generating a subnet address by performing a bitwise AND operation on a network identification (ID) and a subnet mask, the subnet address consisting of a plurality of most significant bits and a plurality of least significant bits, the most significant bits of the subnet address representing a common part of a subnet to be factored out;
storing the most significant bits of the subnet address in a subnet table;
storing the least significant bits of the subnet address in a system table;
factoring out at least one set of data common to two or more subnets;
storing said at least one set of data common to said two or more subnets in the subnet table;
generating an indicator for accessing said at least one set of data; and
storing the indicator in the system table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A processor implemented method of accessing a compressed preferred roaming list (PRL) resulting from generating a subnet address by performing a bitwise AND operation on a network identification (ID) and a subnet mask, the subnet address consisting of a plurality of most significant bits and a plurality of least significant bits, the most significant bits of the subnet address representing a common part of a subnet to be factored out, storing the most significant bits of the subnet address in a subnet table, storing the least significant bits of the subnet address in a system table, factoring out at least one set of data common to two or more subnets, storing said at least one set of data common to said two or more subnets in the subnet table, generating an indicator for accessing said at least one set of data, and storing the indicator in the system table, the method comprising:
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retrieving from the system table remaining data not common to said two or more subnets;
retrieving from the system table the indicator for accessing said at least one set of data common to said two or more subnets;
retrieving from the subnet table said at least one set of data common to said two or more subnets corresponding to the indicator; and
concatenating said at least one set of data common to said two or more subnets with said remaining data to form a complete subnet record.
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12. A processor implemented method of accessing a compressed preferred roaming list (PRL) resulting from generating a subnet address by performing a bitwise AND operation on a network identification (ID) and a subnet mask, the subnet address consisting of a plurality of most significant bits and a plurality of least significant bits, the most significant bits of the subnet address representing a common part of a subnet to be factored out, storing the most significant bits of the subnet address in a subnet table, storing the least significant bits of the subnet address in a system table, factoring out at least one set of data common to two or more subnets, storing said at least one set of data common to said two or more subnets in the subnet table, generating a subnet tag for indicating whether there are any sets of data common to said two or more subnets and for accessing said at least one set of data, and storing the subnet tag in the system table, the method comprising:
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retrieving the subnet tag from the system table;
determining whether the subnet tag is 0;
if the subnet tag is 0, performing the steps of;
retrieving from the system table data not common to said two or more subnets; and
forming a complete subnet record by filling in the subnet record with data not common to said two or more subnets;
if the subnet tag is not 0, performing the steps of;
retrieving from the subnet table said at least one set of data common to said two or more subnets corresponding to the subnet tag;
retrieving from the system table remaining data not common to said two or more subnets; and
concatenating said at least one set of data common to said two or more subnets with said remaining data to form a complete subnet record. - View Dependent Claims (13)
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14. A processor implemented method of accessing a compressed preferred roaming list (PRL) resulting from generating a subnet address by performing a bitwise A.N.D operation on a network identification (ID) and a subnet mask, the subnet address consisting of a plurality of most significant bits and a plurality of least significant bits, the most significant bits of the subnet address representing a common part of a subnet to be factored out, storing the most significant bits of the subnet address in a subnet table, storing the least significant bits of the subnet address in a system table, factoring out at least one set of data common to two or more subnets, storing said at least one set of data common to said two or more subnets in the subnet table, generating a subnet common offset index for accessing said at least one set of data, and storing the subnet common offset index in the system table, the method comprising:
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retrieving from the system table a system record comprising a subnet least significant bit length indicator, a subnet least significant bit field, and the subnet common offset index;
retrieving from the subnet table a subnet record comprising a subnet common length indicator and a subnet common field corresponding to the subnet common offset index; and
concatenating the subnet common field with the subnet least significant bit field to form a complete subnet field. - View Dependent Claims (15, 16)
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Specification