Shared Pilot Averaging Filter for Compact WCDMA Rake Fingers
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Solution Overview
Problem
Existing rake receivers require significant space on a silicon die due to the repetition of identical independent filters for processing pilot symbols across multiple fingers, leading to inefficient use of resources and increased complexity.
Innovation Solution
A shared moving average filter is implemented to multiplex and process outputs from a plurality of pilot signal correlators, allowing a single processing unit to handle all pilot symbols, reducing the need for multiple filters and optimizing memory usage by using a first-in-first-out buffer and multiplexer to serialize and filter pilot symbols efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent filters are used for each finger in rake receiver, then each finger can process pilot symbols independently, but the silicon die space increases significantly
Solution Approach 1:
Multiple independent filter units are merged into a single shared filter unit that serves all fingers. The filter is time-multiplexed to process pilot symbols from different fingers sequentially, eliminating the need for separate filter instances for each finger while maintaining independent processing capability.
Solution Approach 2:
A single filter unit is designed to perform multiple functions by serving different fingers at different time slots. The filter becomes a universal resource that can process pilot symbols from any finger, replacing the need for finger-specific filter instances.
2Adaptability or versatility
If multiple independent filters are implemented, then each finger has dedicated filtering resources, but device complexity increases
Solution Approach 1:
The complex architecture of multiple independent filters is simplified by merging them into a single filter unit with time-multiplexed access. This reduces the overall complexity while maintaining the ability to provide dedicated filtering resources to each finger through temporal separation.
Solution Approach 2:
The shared filter operates in periodic time slots, dedicating specific periods to process pilot symbols from different fingers. This periodic time-multiplexing provides each finger with dedicated filtering resources while using a single filter unit, reducing complexity compared to permanently allocated independent filters.
3Area of stationary object
If a shared filter is used for multiple fingers, then silicon die space is reduced, but resource efficiency may be compromised
Solution Approach 1:
The shared filter operates in periodic time slots, dedicating specific periods to process pilot symbols from different fingers. This ensures that each finger receives adequate filtering resources while sharing the same physical filter unit, maintaining processing efficiency without requiring simultaneous operation of multiple filters.
Solution Approach 2:
The shared filter continuously processes pilot symbols from different fingers in sequence without idle time, ensuring that the filtering function is always active and productive. This continuous operation maximizes the utilization of the single filter unit across all fingers.
Data Source
AI summary
A rake receiver having a shared moving average filter that is operable in a multiplexed manner to receive and filter outputs from a plurality of pilot signal correlators.