WCDMA Multipath Searcher Revisit Control for Fast UL Acquisition
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Solution Overview
Problem
Existing WCDMA receivers face challenges in optimizing the revisit rate of the multipath searcher to minimize the time to acquire an uplink transmission while managing CPU loading efficiently, especially in software-based implementations.
Innovation Solution
A dynamic adjustment of the multipath searcher's revisit rate is implemented with two modes of operation: Acquisition Mode with a 100% revisit rate for initial acquisition and Steady-state Mode with a reduced revisit rate for optimized processing load, triggered by successful detection or timer expiration, with adaptable revisit rates within configurable limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the multipath searcher operates with a 100% revisit rate continuously, then the time to acquire uplink transmission is minimized, but the CPU loading becomes excessively high
Solution Approach 1:
The patent applies dynamics by making the revisit rate adjustable and time-varying. The system transitions from a static 100% revisit rate to a dynamic revisit rate that adapts based on operational phase (acquisition vs. steady-state) and channel conditions, thereby optimizing the balance between acquisition speed and processing load
Solution Approach 2:
The patent implements periodic action by using different revisit rates for different time periods. During acquisition mode, 100% revisit rate is used initially, then transitions to a lower periodic revisit rate in steady-state mode. This periodic variation in search intensity reduces overall CPU loading while maintaining acquisition capability
2Use of energy by moving object
If the multipath searcher operates with a reduced revisit rate, then the CPU loading is optimized, but the time to acquire uplink transmission increases
Solution Approach 1:
The patent applies preliminary action by performing initial acquisition with 100% revisit rate before transitioning to reduced revisit rate. This preliminary high-intensity search phase ensures rapid acquisition is achieved first, then the system can afford to reduce processing intensity for ongoing operation
Solution Approach 2:
The system dynamically adjusts the revisit rate based on the operational state. The revisit rate is high during acquisition phase to minimize acquisition time, then transitions to a lower dynamic revisit rate in steady-state, creating a time-varying optimization strategy that addresses both concerns
3Ease of operation
If the revisit rate is fixed, then the system operation is simple, but the system cannot adapt to changing channel conditions
Solution Approach 1:
The patent implements dynamics by making the revisit rate a variable parameter that adapts to channel conditions. The system transitions from a fixed revisit rate to a dynamic revisit rate that can be adjusted based on measured channel characteristics, UE mobility, and operational phase, thereby achieving adaptability while maintaining manageable complexity through structured adjustment rules
Data Source
AI summary
A method for dynamically adjusting the revisit rate of a rake receiver for an individual UE is disclosed, such that the time to initially acquire the UL transmission is optimized while the ongoing Central Processing Unit (CPU) loading during normal operation is minimized. The method may comprise operating a multipath searcher in a first mode of operation at a first time, the first mode being an acquisition mode, the multipath searcher operating with a revisit rate of 100 percent; and, operating the multipath searcher in a second mode of operation at a second time, the second mode being a steady-state mode and the multipath searcher operating with a revisit rate of less than 100 percent.