Rake Receiver Tap Selection Using Dual Path Searchers

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Solution Overview

Problem

In wireless communication systems, receivers face challenges in detecting all channel taps, especially when dealing with continuous adjacent carriers, as existing path searchers may miss taps due to fading and resource constraints, leading to suboptimal Signal-to-Interference Ratio and power issues.

Innovation Solution

A receiver apparatus and method that employs two path searchers to detect taps for each carrier and a channel tap selector to choose the highest energy values for both carriers, ensuring accurate tap selection and improved synchronization, even when taps are weak in one carrier but strong in the adjacent carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single path searcher is used to detect taps for each carrier, then device complexity is reduced, but tap detection accuracy deteriorates due to fading and resource constraints

Engineering Contradiction:
Improvereceiver structureVSAvoidtap detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The receiver is divided into two independent path searchers, each dedicated to detecting taps for a specific carrier. This segmentation allows each path searcher to focus on one carrier's channel conditions, improving detection accuracy for each individual carrier while maintaining manageable complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tap detection results from two separate path searchers are merged by selecting the highest energy values across both carriers. This combining approach leverages the diversity between carriers, where a tap that is weak in one carrier may be strong in the other, thereby improving overall tap detection accuracy and Signal-to-Interference Ratio.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If separate path searchers are used for each carrier, then tap detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvetap detection accuracyVSAvoidreceiver structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Both path searchers use the same detection algorithm and processing logic, making them universal in function. This multi-functionality approach allows the system to handle multiple carriers with identical processing techniques, improving detection accuracy across carriers while avoiding the complexity of developing and maintaining different detection methods for each carrier.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the operational parameters (carrier frequency) between the two path searchers while maintaining the same detection methodology. This parameter change allows the receiver to exploit carrier diversity and improve tap detection accuracy without fundamentally changing the receiver architecture, thus managing complexity effectively.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If all available taps are used for signal processing, then Signal-to-Interference Ratio is improved, but power consumption increases due to processing overhead

Engineering Contradiction:
ImproveSignal-to-Interference RatioVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies different quality levels of tap selection to different carriers by selecting only the highest energy taps from each carrier's path searcher results. This local quality approach ensures that the most reliable taps (those with highest energy) are used for signal processing, improving Signal-to-Interference Ratio while avoiding the power consumption overhead of processing all detected taps.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2982043B1Apparatus and method for jointly selecting the tap values and delays of the fingers for a rake receiver of two carriers
Publication Date: 2018.12.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2982043B1 patent drawingFigure 1
  • EP2982043B1 patent drawingFigure 2
  • EP2982043B1 patent drawingFigure 3

AI summary

The present disclosure concerns receivers for use in nodes or devices that participate in wireless communications. In one exemplary embodiment, the receiver 20 receives a first signal 22-1 attributable to a first carrier and a second signal attributable to a second carrier 22-2. A first path searcher 24-1 detects taps in the first signal 22-1 attributable to the first carrier. A second path searcher 24-2 detects taps in the second signal 22-1 attributable to the second carrier. A channel tap selector 30 selects, based on received energy values for taps detected by the first path searcher 24-1 and the second path searcher 24-2, which tap values are to be used for taps of the receiver 20 for both the first carrier and the second carrier.