LTE-TDD Special Subframe Configuration Coordination
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Solution Overview
Problem
In LTE-TDD systems, adjacent cells lack knowledge of each other's special subframe configurations, leading to interference between base stations, particularly during DwPTS transmission affecting uplink receptions in neighboring cells.
Innovation Solution
A method and apparatus for determining the configuration of special subframes in cells by exchanging notification information about neighboring cell configurations, selecting configurations that minimize interference by adjusting the Guard Period (GP) length and avoiding time slot correspondences that cause interference, and setting usage priorities based on interference levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cells independently configure special subframes without knowledge of neighbor cell configurations, then each cell can independently optimize its own performance, but inter-cell interference occurs between adjacent cells
Solution Approach 1:
The patent implements a feedback mechanism where each cell broadcasts its special subframe configuration to neighboring cells, and each cell adjusts its configuration based on the received neighbor configurations. This feedback loop enables coordinated configuration that reduces inter-cell interference while maintaining operational flexibility.
Solution Approach 2:
The patent introduces configuration notification messages as an intermediary mechanism that carries special subframe configuration information between cells. This intermediary enables indirect communication and coordination between cells, allowing them to adjust configurations to avoid interference without direct cell-to-cell negotiation.
2Reliability
If the Guard Period length is extended to reduce interference, then uplink reception reliability improves, but downlink transmission time is reduced
Solution Approach 1:
The patent enables dynamic adjustment of the Guard Period length based on the detected neighbor cell configurations and interference conditions. Instead of using a fixed Guard Period, the system can adaptively select different Guard Period durations to balance uplink reception reliability and downlink transmission time requirements for each cell.
Solution Approach 2:
The patent changes the Guard Period parameter based on configuration coordination with neighboring cells. By selecting from multiple possible Guard Period lengths according to the coordinated configuration, the system optimizes the trade-off between uplink reception reliability and downlink transmission time for each cell's specific environment.
3Productivity
If DwPTS time slot is extended to increase downlink capacity, then downlink throughput improves, but interference with uplink reception in adjacent cells increases
Solution Approach 1:
The patent performs preliminary configuration coordination by broadcasting special subframe configurations to neighboring cells before actual transmission begins. This allows adjacent cells to advance their configuration decisions and adjust their uplink reception timing accordingly, preventing DwPTS-to-uplink interference before it occurs.
Solution Approach 2:
The patent enables asymmetric configuration where different cells can have different special subframe structures optimized for their specific interference environments. One cell may have a longer DwPTS while its neighbor has a longer Guard Period or shifted timing, creating an asymmetric pattern that reduces mutual interference while maintaining overall system capacity.
Data Source
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AI summary
A method and an apparatus for determining the configuration mode of special subframe of a cell are provided, and the method includes: receiving notification messages sent from adjacent cells, and the notification messages containing the information indicating the configuration modes of special subframes of the adjacent cells; determining the configuration modes of special subframes of the adjacent cells in accordance with the notification messages; among the possible configuration modes of special subframes of the current cell, selecting preferably a configuration mode of special subframe, which meets the interference requirement of the current cell and has less interference with the adjacent cells, as the current configuration mode of special subframe. The embodiments of the present invention also provide a method and an apparatus for determining the usage mode of the time-domain resource of a cell.