Mobile Subscriber Unit Link Record for Handoff Optimization
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Solution Overview
Problem
Mobile subscriber units in wireless communication networks face inefficiencies in maintaining stable connections due to extensive scanning for neighboring access points and channels, which consumes time, battery power, and may result in dropped connections during handoffs, especially without pre-assessment of channel occupancy and interference.
Innovation Solution
A technique where mobile subscriber units build a link record of handoff experiences with access points and affiliated channels, allowing for self-devised handoffs based on this data without additional scanning, and optionally share this record with other units for improved connectivity decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mobile subscriber units perform extensive scanning for neighboring access points and channels, then handoff decisions can be made with more information, but communication overhead, processing time, and battery power consumption increase significantly
Solution Approach 1:
The system performs preliminary scanning and builds a database of neighboring access points and channel conditions in advance, before handoff is actually needed. This pre-collected information is stored and reused for future handoff decisions, eliminating the need for repeated extensive scanning at the moment of handoff.
Solution Approach 2:
Instead of performing complete scanning operations each time a handoff decision is needed, the system creates copies of previously collected scanning data and reuses this information. The database of neighboring APs and channel conditions serves as a copied version of the physical scanning process, reducing repeated work.
2Reliability
If mobile subscriber units dwell receiver for significant time on each channel to find neighboring BSSIDs, then coverage assessment is more thorough, but connection stability deteriorates as current connection weakens during scanning
Solution Approach 1:
The system performs coverage assessment and neighboring BSSID discovery in advance, building a database of available networks and their characteristics before they are needed for handoff decisions. This preliminary action ensures thorough coverage assessment without compromising current connection stability.
Solution Approach 2:
The patent introduces an intermediary database that stores information about neighboring access points and channel conditions. This database acts as a mediator between the physical scanning process and handoff decisions, allowing the system to rely on stored information rather than continuous scanning that would destabilize the current connection.
3Reliability
If mobile subscriber units perform scanning without pre-assessment of channel occupancy, then all available channels are evaluated, but time and power are wasted on channels that are occupied or unsuitable
Solution Approach 1:
The system performs preliminary assessment of channel occupancy and suitability before conducting full scanning operations. By evaluating basic channel characteristics in advance and storing this information in a database, the system can avoid wasting energy on scanning occupied or unsuitable channels during actual handoff scenarios.
Solution Approach 2:
Instead of performing complete scanning on all channels every time, the system applies partial scanning based on pre-assessed channel occupancy information. It focuses scanning efforts only on channels that are likely to be suitable, performing excessive assessment only where needed rather than uniformly across all channels.
4Reliability
If IEEE 802.11k Radio Resource Measurements data is used for handoff decisions, then RF conditions information is available, but active messaging between MSU and AP increases overhead and may interrupt active sessions
Solution Approach 1:
The system extracts and stores RF conditions information from active messaging into a local database during periods when messaging is already occurring. By taking out this information and storing it locally, the system reduces the need for additional active messaging specifically for handoff decisions, thereby reducing overhead and synchronization complexity.
Solution Approach 2:
The mobile subscriber unit serves itself by maintaining a local database of RF conditions and neighboring access point information. Rather than relying on continuous active messaging with the network for this information, the system uses its own stored data for handoff decisions, reducing network overhead and messaging complexity.
Data Source
AI summary
An apparatus and method for establishing mobile connectivity conditions for mobile subscriber units in a wireless communication network includes scanning, by each mobile subscriber unit, for candidate access points and affiliated channels for roaming, whereupon the unit can roam from an originating access point to one of the candidate access points on an affiliated channel for roaming. A link record in the mobile subscriber unit is used for recording an entry including the originating access point, the candidate access point, the affiliated channel for roaming, and a handoff experience value. The link record can be used upon subsequent roaming of the unit to attempt a self-devised handoff without further scanning for access points and affiliated channels. Link records can be shared between mobile subscriber units to speed up map building of link records.