Interference Cancellation Circuit Sector Management
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Solution Overview
Problem
Conventional CDMA receivers are interference-limited and struggle to effectively cancel multiple access interference, limiting their capacity to handle a large number of interfering signals.
Innovation Solution
The method involves generating and managing a set of sectors, including both active and candidate sectors, to create an interference estimate for an interference cancellation circuit, where a receiver finger is assigned to each sector in the set to cancel interference based on this estimate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional matched filter CDMA receivers are used, then the receiver structure is simple, but the receiver is inherently interference-limited and cannot effectively cancel multiple access interference
Solution Approach 1:
The receiver is divided into multiple functional components: a correlation receiver for despreading signals, an interference cancellation component for estimating and subtracting interference, and a set management component for tracking active and candidate sectors. This segmentation allows each component to perform a specific function, improving overall interference cancellation capability while maintaining manageable system complexity.
Solution Approach 2:
The receiver performs preliminary interference estimation and cancellation before final signal detection. By proactively identifying and removing interference from multiple access signals in advance, the receiver improves its ability to handle strong interferers without requiring complete structural redesign.
2Reliability
If the receiver tracks only active set sectors, then the receiver complexity is reduced, but the receiver cannot effectively cancel interference from candidate sectors
Solution Approach 1:
The receiver's correlation receiver is designed to serve multiple functions: it processes signals from active set sectors for primary communication while simultaneously processing signals from candidate sectors for interference cancellation. This multi-functionality allows the receiver to cancel interference from all sectors without requiring separate dedicated receivers for each sector type.
Solution Approach 2:
A set management component acts as an intermediary between the correlation receiver and the interference cancellation component. It manages the active set and candidate set, determining which sectors should be tracked and providing this information to the interference cancellation component, thereby coordinating the tracking of multiple sectors without direct complex interactions between all components.
3Reliability
If the receiver processes all sectors for interference cancellation, then the interference cancellation capability is maximized, but the computational complexity and processing overhead increase
Solution Approach 1:
The receiver applies different processing qualities to different sectors based on their importance. Active set sectors receive full processing attention for primary communication, while candidate sectors receive processing focused specifically for interference cancellation purposes. This localized quality approach optimizes computational resources by applying appropriate processing depth to each sector type.
Solution Approach 2:
The receiver performs partial processing on candidate sectors, focusing only on the aspects needed for interference cancellation rather than complete signal processing. This partial action approach provides sufficient interference cancellation capability without the full computational overhead of processing all sectors to the same level as active set sectors.
Data Source
AI summary
Apparatus and methods, in several embodiments, are disclosed for generating and managing a set of sectors, the signals received from which are utilized to generate an interference estimate for use by an interference cancellation circuit. The set of sectors generally includes a subset of the combined set of sectors in the Active Set and the Candidate Set for an access terminal. A finger of a receiver at an access terminal can be assigned to each sector in the set of sectors for interference cancellation to improve receiver operations.