PRL Format Extension for WLAN System Selection
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Solution Overview
Problem
Current wireless devices can only select and acquire 1x and 1xEV-DO systems due to limitations in the Preferred Roaming List (PRL) format, which does not support system selection and acquisition for WLAN systems, restricting their ability to seamlessly switch between WWAN and WLAN networks.
Innovation Solution
The introduction of enhanced PRL formats that include new system and acquisition records for WLAN systems, allowing backward compatibility with existing TIA-683-C standards, and the use of a network identifier table to store system records and profile information for efficient system selection and acquisition, including security-related details for WLAN systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the PRL format is extended to include WLAN system records, then system selection capability for WLAN is improved, but backward compatibility with existing TIA-683-C standards deteriorates
Solution Approach 1:
The patent embeds WLAN system records and acquisition records within the existing PRL structure, nesting new functionality inside the established format. The PRL is extended to include system records for both WWAN and WLAN systems, with each record type containing technology-specific fields that are nested within the universal PRL framework, allowing legacy parsers to ignore unknown record types while new parsers can utilize all record types.
Solution Approach 2:
The patent creates a universal PRL structure that can accommodate multiple system types (WWAN and WLAN) through a common record format. The system records are designed with technology-specific fields that can represent different wireless technologies, allowing the same PRL structure to serve multiple functions across different network types while maintaining a unified selection mechanism.
2Adaptability or versatility
If new system and acquisition records are added to support WLAN, then WLAN system acquisition is enabled, but PRL structure complexity increases
Solution Approach 1:
The patent segments the PRL into distinct record types (system records and acquisition records) with clear demarcations between WWAN and WLAN specific fields. Each record type is further segmented into technology-independent header fields and technology-specific payload fields, allowing the structure to be processed in manageable segments and reducing overall complexity through organized modularity.
Solution Approach 2:
The patent adds a new dimension to the PRL structure by introducing record type identifiers and technology-specific field sections. Rather than creating a completely new data structure, the invention extends the existing one-dimensional PRL format into a multi-dimensional structure that can accommodate different record types and technology variations while maintaining the original format's core properties.
Data Source
AI summary
A preferred roaming list (PRL) carries system and acquisition records for wireless wide area network (WWAN) systems and wireless local area network (WLAN) systems. New system and acquisition records may be defined for WLAN. The PRL and system and acquisition records may be defined to be backward compatible with TIA-683-C. System and acquisition information for WLAN systems may be stored in the new system and acquisition records, respectively. Information used to perform encryption and/or authentication for WLAN systems may be stored in a separate WLAN authentication profile table. The system record for each WLAN system indicates a acquisition record and a profile record for that WLAN system. A network identifier table may also carry system records and profile records for WLAN systems. The system records carry information used for WLAN system selection and acquisition. The profile records carry information used to perform encryption and/or authentication for WLAN systems.