Access Terminal Handoff Decision Mechanism for Wireless Load Balancing

Solution Overview

Problem

In wireless communications systems, there is a need for efficient handoff mechanisms that facilitate load balancing across multiple base station attachment points, considering varying user needs and service levels, while avoiding the inefficiencies of centralized system control.

Innovation Solution

Access terminals receive indicators of unused communication resources and best effort user information from base stations to make intelligent handoff decisions, selecting attachment points that maximize throughput or meet quality of service requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a centralized system control node approach is used for load balancing, then system-wide load distribution can be achieved, but system architecture complexity and control signaling overhead increase significantly

Engineering Contradiction:

Improveload balancing efficiencyVSAvoidsystem architecture complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The access terminal autonomously performs handoff decisions by evaluating channel conditions and comparing signal strengths from multiple attachment points without requiring centralized control. The terminal independently determines when to switch between attachment points based on predefined criteria, eliminating the need for complex centralized control architecture while achieving effective load balancing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of having the system controller direct handoff decisions to terminals (top-down control), the invention inverts the control direction by enabling terminals to make their own handoff decisions (bottom-up autonomy). This inversion simplifies system architecture while maintaining load balancing effectiveness through distributed intelligence.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If centralized control signaling is implemented for handoff decisions, then coordinated load balancing can be achieved, but control signaling delays and overhead increase

Engineering Contradiction:

Improvehandoff coordination efficiencyVSAvoidcontrol signaling delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The access terminal autonomously performs handoff decisions by evaluating channel conditions and comparing signal strengths from multiple attachment points without requiring centralized control. The terminal independently determines when to switch between attachment points based on predefined criteria, eliminating the need for complex centralized control architecture while achieving effective load balancing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system pre-configures handoff thresholds and criteria in the access terminal before handoff situations arise. When signal strength conditions are met, the terminal immediately executes handoff based on pre-established rules, eliminating the time delay associated with real-time centralized control signaling and decision-making.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If access terminals make autonomous handoff decisions, then control signaling overhead is reduced, but ability to optimize system-wide load balancing decreases

Engineering Contradiction:

Improvecontrol signaling overheadVSAvoidsystem-wide load balancing optimization

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The access terminal autonomously performs handoff decisions by evaluating channel conditions and comparing signal strengths from multiple attachment points without requiring centralized control. The terminal independently determines when to switch between attachment points based on predefined criteria, eliminating the need for complex centralized control architecture while achieving effective load balancing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts handoff parameters such as threshold values and weighting factors based on network conditions and attachment point load states. This allows autonomous terminals to adapt their handoff behavior to system-wide conditions, maintaining load balancing optimization capability while preserving the benefits of reduced control signaling overhead.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9179385B2Methods and apparatus for making handoff decisions in access terminals capable of operating at different times in best effort and QoS modes of traffic operation

Publication Date: 2015.11.03 QUALCOMM INC

AI summary

Methods and apparatus for making handoff decisions in an access terminal which can support both best effort and QoS traffic, e.g., when operating in a best effort and QoS mode of operation, respectively, are described. The access terminal receives an indicator indicating the fraction of communications resources not utilized for QoS service and information indicating a number of best effort users being supported by the attachment point. During Qos mode operation, connections to attachment points which can support the access terminal's minimal QoS requirements are identified and then from among the identified set, the attachment point which can provide a connect supporting the most best effort traffic from the access terminal is selected. In best effort mode operation the access terminal selects the attachment point connection which will provide the greatest amount of throughput to the access terminal for best effort traffic.