Extended Search Space for Carrier Aggregation Control Signals
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Solution Overview
Problem
The 3GPP LTE-A system faces challenges in efficiently scheduling and transmitting control information due to limitations in search space configuration, leading to increased PDCCH blocking probability and reduced flexibility, especially in multi-cell environments and carrier aggregation scenarios.
Innovation Solution
A method for detecting control signals in a wireless access system that supports multiple carrier aggregation and cross-carrier scheduling, involving the calculation of starting points for extended search spaces with predetermined offset values and blind decoding to effectively search for control signals from a base station, allowing for flexible configuration of search spaces using primary, anchor, or self-scheduling component carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-carrier scheduling is used to transmit multiple PDCCHs through one DL CC, then carrier aggregation capability is improved, but the number of candidate PDCCHs becomes insufficient leading to increased blocking probability
Solution Approach 1:
The patent extends the search space from the conventional single-carrier dimension to a multi-carrier dimension by introducing an extended search space that spans multiple component carriers. This dimensional expansion allows the system to accommodate multiple PDCCHs across different carriers, resolving the blocking issue while maintaining carrier aggregation flexibility.
Solution Approach 2:
The extended search space is segmented into multiple candidate PDCCH positions distributed across different component carriers. Each carrier contributes a portion of the total search space, dividing the scheduling burden and enabling reliable PDCCH transmission without concentrating all candidates on a single carrier.
2Object-generated harmful factors
If multiple PDCCHs are concentrated on a specific DL CC for interference coordination, then network coordination is improved, but the search space resources become insufficient
Solution Approach 1:
Instead of concentrating search space resources on a single carrier, the patent distributes the extended search space across multiple component carriers. This dimensional distribution provides both interference coordination benefits (by allowing specific carriers to be optimized) and sufficient total search space resources (by aggregating across carriers).
3Device complexity
If the search space is configured with a limited number of candidate PDCCHs in LTE system, then system simplicity is maintained, but scheduling flexibility is deteriorated
Solution Approach 1:
The extended search space mechanism serves multiple functions: it maintains backward compatibility with existing LTE search space configurations while simultaneously enabling carrier aggregation and cross-carrier scheduling. The same extended search space framework adapts to different carrier aggregation scenarios without requiring separate configuration mechanisms.
Data Source
AI summary
The present invention relates to a wireless access system supporting carrier aggregation and carrier aggregation technology, and discloses methods for effectively detecting control signals for a plurality of cells and apparatuses supporting same. In an embodiment of the present invention, a method for detecting control signals in a wireless access system supporting multiple carrier aggregation (CA) and cross carrier scheduling may comprise calculating the start point of a reference search space in an expanded search space, calculating start points of the next search spaces which are spaced apart from the reference search space by a predetermined offset value, and performing blind decoding on the reference search space and subsequent search spaces to search control signals from a base station.