Cross-RAT Channel Quality Indicator Mapping for Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in reporting downlink channel quality for secondary radio access technologies (RATs) without an uplink carrier configured, leading to difficulties in transmitting control information and channel quality indicators across different RATs during carrier aggregation.
Innovation Solution
A method in user equipment for determining and mapping channel quality indicators from a secondary RAT to the format used by a primary RAT, allowing transmission over the primary RAT's uplink carrier, which may involve adapting or quantizing indicator formats and using extended transmission structures to ensure accurate and efficient reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with multiple RATs to increase spectrum utilization, then spectrum efficiency and resource utilization improve, but device complexity and control information transmission difficulty increase
Solution Approach 1:
The patent uses the primary RAT's uplink carrier as an intermediary to transmit channel quality indicators for the secondary RAT. Instead of requiring separate uplink carriers for each RAT, the invention maps CQI information from the secondary RAT onto the primary RAT's uplink transmission resources, enabling cross-RAT feedback through a single uplink interface.
Solution Approach 2:
The primary RAT's uplink carrier is designed to serve multiple functions: it carries both primary RAT control information and secondary RAT channel quality indicators. This multi-functionality allows a single uplink interface to support feedback for multiple RATs, reducing the need for additional dedicated uplink resources.
2Adaptability or versatility
If indicator format mapping is implemented to enable cross-RAT CQI reporting, then compatibility and transmission capability improve, but measurement precision and reporting accuracy may be affected
Solution Approach 1:
The patent transforms channel quality indicator parameters from the secondary RAT's native format to the primary RAT's expected format through mapping functions. This parameter transformation enables compatibility between different RATs while preserving the essential channel quality information through carefully designed mapping relationships.
Solution Approach 2:
The invention creates a mapped representation of the secondary RAT's CQI information that conforms to the primary RAT's indicator format. This copied representation maintains the critical channel quality characteristics while adapting to the target system's requirements, enabling accurate feedback without direct format compatibility.
Data Source
AI summary
The invention relates to a method (90) in a user equipment (4) for reporting a downlink channel quality in a communication system (1) comprising a first radio access technology system (2) and a second radio access technology system (3). The user equipment (4) is in connection with a primary serving cell on the first radio access technology system (2) and with a secondary serving cell on the second radio access technology system (3). The method (90) comprises: determining (110) channel quality for the second radio access technology system (3) using an indicator format of the radio access technology of the second radio access technology system (3); mapping (120) an indicator of the channel quality having the indicator format of the second radio access technology to an indicator format used for channel quality indicators in the first radio access technology system (2); and transmitting (130) the indicator of the channel quality for the second radio access technology system (3) to the communication system (1) using the indicator format of the first radio access technology on an uplink carrier of the first radio access technology system (2). The invention also relates to a user equipment, methods in a network node and a network node.