Search Space Configuration for Unlicensed Band Control
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Solution Overview
Problem
In wireless communication systems supporting unlicensed bands, user equipment faces challenges in efficiently receiving downlink control information due to overlapping search spaces across different carriers, leading to scheduling restrictions.
Innovation Solution
A method for configuring a search space for receiving downlink control information from a base station in a wireless communication system, where the search space for a specific aggregation level is determined based on the maximum number of candidates for downlink control channels across multiple unlicensed bands, using equations to optimize the search space configuration for physical and enhanced physical downlink control channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If search spaces are configured for multiple unlicensed bands, then the user equipment can receive downlink control information from multiple carriers, but the search spaces may overlap causing scheduling restrictions
Solution Approach 1:
The search space is divided into different types: first search space for common control information and second search space for UE-specific control information. This segmentation allows different control information to be monitored in separate spaces, preventing overlap and scheduling restrictions while maintaining the ability to receive control information from multiple carriers.
Solution Approach 2:
Different search spaces are configured with different monitoring characteristics and aggregation levels. The first search space monitors common control information with specific aggregation levels, while the second search space monitors UE-specific control information with different aggregation levels. This local differentiation prevents overlap and resolves scheduling conflicts.
2Adaptability or versatility
If the number of search spaces is increased to support multiple carriers, then the coverage of downlink control information is improved, but the complexity of search space configuration increases
Solution Approach 1:
The search space configuration uses universal parameters that can be applied across multiple carriers. The same configuration framework and parameter sets are used for both first and second search spaces, allowing the system to support multiple carriers without proportionally increasing configuration complexity.
Solution Approach 2:
The system manages search space complexity by changing parameters such as aggregation levels and monitoring configurations rather than creating entirely new search space structures. This allows extended coverage across multiple carriers while maintaining manageable configuration complexity through parameter variation.
3Reliability
If aggregation levels are increased to improve control information reception, then the reliability of downlink control information is improved, but the number of candidates to monitor increases
Solution Approach 1:
The monitoring task is segmented by dividing control information into common and UE-specific types, each monitored in separate search spaces with appropriate aggregation levels. This segmentation allows the system to achieve reliable reception through targeted aggregation levels without unnecessarily increasing the total number of candidates to monitor across all search spaces.
Data Source
AI summary
Disclosed in the present invention are: a method for transmitting and receiving a downlink signal between a terminal and a base station in a Licensed Assisted Access (LAA) system in which the base station or the terminal transmits a Listen-Before-Talk (LBT) based signal; and a device for supporting the same. Specifically, disclosed in the present invention are:a method for allowing a terminal to novelly define a search space to be monitored, in order to receive the downlink control channel corresponding to a specific aggregation level and, on the basis of this, transmitting and receiving the downlink signal between the terminal and the base station; and a device supporting the same.