LTE-A Aggregated Cell TDD Collision Subframe Handling
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Solution Overview
Problem
In LTE-A systems, the challenge lies in managing uplink/downlink collision subframes due to different TDD configurations across aggregated cells, leading to unidirectional data transmission limitations and a lack of clear processing methods for these collisions.
Innovation Solution
The proposed solution involves determining the allowed data transmission direction and identifying available subframes for each cell, excluding uplink/downlink collision subframes, allowing for efficient data transmission by utilizing PDCCH or E-PDCCH subframes, and adjusting DRX timer counting methods to exclude or include collision subframes based on transmission directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different TDD configurations are applied to aggregated cells to increase flexibility and spectrum utilization, then adaptability is improved, but uplink/downlink collision subframes occur causing transmission conflicts
Solution Approach 1:
The patent applies local quality by determining transmission directions on a per-cell basis for each subframe. Each cell can have its own transmission direction (uplink or downlink) independently determined based on its TDD configuration, allowing different parts of the aggregated system to have different transmission characteristics. This resolves the contradiction by enabling flexible TDD configurations locally while ensuring reliable transmission through coordinated direction determination at the network side.
2Reliability
If unidirectional transmission is enforced in collision subframes to avoid interference, then transmission reliability is improved, but data transmission efficiency deteriorates due to restricted transmission directions
Solution Approach 1:
The patent applies dynamics by making the transmission direction determination dynamic rather than static. The network side dynamically determines the transmission direction for each cell in each subframe based on current system state, TDD configurations, and collision conditions. This allows the system to adapt transmission directions in real-time, improving efficiency while maintaining reliability through dynamic coordination.
Solution Approach 2:
The patent implements feedback mechanisms where the network side determines transmission directions and this determination is communicated to user equipment. The system uses feedback loops to coordinate transmission directions across aggregated cells, ensuring that collision subframes are handled reliably while maintaining overall transmission efficiency through informed decision-making based on system state feedback.
3Use of energy by moving object
If DRX timer counting includes all subframes for power saving, then energy efficiency is improved, but timing accuracy deteriorates due to ambiguous collision subframe handling
Solution Approach 1:
The patent applies parameter changes by modifying how DRX timer counting is performed based on transmission direction parameters. The system changes the counting behavior of DRX timers to account for collision subframes with unidirectional transmission, adjusting the timing parameters to reflect the actual transmission opportunities. This resolves the contradiction by making timer counting accurate (excluding ambiguous collision subframes) while still achieving power saving through DRX operation.
Data Source
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AI summary
Disclosed are a method and device for data transmission, for improving a data transmission processing solution when a plurality of aggregated cells of user equipment have different TDD UL/DL configurations. The method includes: when the time division duplex up/downlink configurations of a plurality of aggregated cells of user equipment (UE) and only bidirectional data transmission is allowed in an up/downlink collision subframe, the UE determining the allowed data transmission direction of the up/downlink collision subframe, wherein in the time division duplex up/downlink configurations of the plurality of aggregated cells of UE, the data transmission directions of the same up/downlink collision subframe are different; the UE respectively determining available subframes for use in the uplink data transmission direction and available subframes for use in the downlink data transmission direction in each aggregated cell thereof, wherein in the available subframes counted in a data transmission direction opposite to the allowed data transmission direction, the up/downlink collision subframe is not included therein; and the UE performing data transmission in the available subframes.