UE Measurement Gap Configuration for TDD Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE-A with Carrier Aggregation (CA) for TDD cells, there is a need for reliable data transmission and reception across aggregated carriers with different frequency bands and subframe patterns, which poses challenges in configuring measurement gaps and reporting Rank Indication (RI) for MIMO operations.
Innovation Solution
A method and apparatus for a User Equipment (UE) to receive configuration information for a measurement gap, identify subframes, and adjust operations accordingly, including blocking uplink transmissions in specific subframes to align with downlink receptions, enabling reliable data transmission and reception across TDD cells with different subframe configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs measurements during configured subframes in TDD mode with carrier aggregation, then measurement coverage is improved, but uplink transmission reliability deteriorates due to subframe conflicts between different aggregated carriers
Solution Approach 1:
The network pre-configures measurement gaps to the UE before measurements are performed. These measurement gaps are specifically scheduled to avoid conflicting with uplink transmission subframes, ensuring that measurements can be conducted without compromising uplink reliability. The UE is instructed to perform measurements only during these pre-arranged gap periods.
Solution Approach 2:
Measurement gaps act as an intermediary time resource that separates measurement activities from regular uplink/downlink transmissions. By introducing these dedicated measurement periods, the system resolves the conflict between measurement requirements and uplink transmission reliability, allowing both functions to coexist without interference.
2Productivity
If the UE aggregates multiple TDD carriers with different subframe patterns, then data transmission capacity is improved, but coordination complexity increases due to misaligned subframe boundaries
Solution Approach 1:
The UE is designed to handle multiple TDD carrier configurations with different subframe patterns simultaneously. The device maintains the capability to identify and process subframe structures across multiple carriers, determining whether each subframe is an uplink or downlink subframe independently for each carrier, thereby supporting aggregated carriers with different configurations.
Solution Approach 2:
The system dynamically adjusts the timing of measurement gaps and transmission operations based on the specific subframe configurations of aggregated carriers. By changing operational parameters such as measurement gap timing and transmission scheduling according to the detected subframe patterns, the system optimizes performance while managing the complexity of coordinating multiple carriers with different structures.
3Measurement precision
If the UE blocks uplink transmission in subframes following measurement gaps, then measurement accuracy is improved, but transmission time loss increases
Solution Approach 1:
The network pre-configures measurement gaps with specific timing and duration parameters to the UE. These gaps are scheduled in advance to ensure adequate time for accurate measurements while minimizing impact on transmission operations. The UE performs measurements during these pre-defined gaps and blocks uplink transmission only for the necessary duration immediately following the gap.
Solution Approach 2:
The UE blocks uplink transmission for a limited period immediately following measurement gaps when needed, rather than continuously blocking transmissions. This partial blocking approach ensures measurement accuracy is achieved while minimizing the overall loss of transmission time, allowing normal transmissions to resume as soon as the measurement requirement is satisfied.
Data Source
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AI summary
The invention provides a method for a user equipment (UE) apparatus and a method for a base station (BS) in a wireless communication system, as well as the UE and the BS. The method for the UE comprises: receiving, from the base station, BS, by the UE, configuration information related to a measurement gap during which the UE does not transmit uplink data; identifying at least one sub frame (3310) of the measurement gap based on the configuration information; starting, by the UE, measurements corresponding to the measurement gap at an end of a subframe (3305) occurring immediately before the measurement gap based on the identified subframe (3310); and determining an operation in a subframe immediately after the measurement gap, in response to identifying that the subframe occurring immediately before the measurement gap is a downlink subframe.