Flexible Subframe Interference Control in LTE Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interference between cells in wireless communication systems, particularly in LTE and LTE-Advanced systems, degrades performance due to signal interference between evolved Node B and terminals in adjacent cells.
Innovation Solution
A method and apparatus for controlling interference by determining whether a subframe is flexible for downlink transmission, measuring non-period channel information, and transmitting this information through uplink subframes to manage interference, including uplink protection subframes and flexible subframe operations to suppress uplink transmission and adjust scheduling information accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible subframes are used for downlink transmission in TDD systems, then system adaptability and resource utilization are improved, but interference between adjacent cells increases due to non-synchronized uplink/downlink switching
Solution Approach 1:
The patent implements feedback mechanisms where terminals report channel quality indicators (CQI) and interference measurements to the base station. The base station uses this feedback to dynamically adjust scheduling decisions, modify subframe configurations, and coordinate with neighboring cells to minimize interference while maintaining flexible subframe operations.
Solution Approach 2:
The patent enables dynamic subframe configuration where uplink and downlink subframes can be flexibly assigned based on real-time traffic demands. The system can dynamically switch between different TDD uplink-downlink configurations and adjust the timing of flexible subframes to optimize resource utilization while coordinating with neighboring cells to reduce interference.
2Measurement precision
If non-period channel information is measured and transmitted in flexible subframes, then interference control precision is improved, but uplink transmission overhead increases
Solution Approach 1:
The patent changes the transmission parameters of channel information by adjusting the periodicity, timing, and content of CQI reports based on the flexible subframe configuration. The system can switch between periodic and aperiodic reporting modes, and adjust the granularity of channel information transmitted to balance measurement precision with uplink overhead.
Solution Approach 2:
The patent implements selective transmission of channel information where only relevant or changed parameters are reported in flexible subframes rather than complete periodic reports. This partial action approach reduces uplink overhead while maintaining sufficient measurement precision for interference control by transmitting only the most critical channel state information.
3Object-affected harmful factors
If uplink protection subframes are introduced to suppress uplink transmission, then interference between cells is reduced, but system productivity decreases due to lost transmission opportunities
Solution Approach 1:
The patent applies preliminary action by proactively identifying and configuring protection subframes in advance based on predicted interference patterns and traffic demands. The base station pre-coordinates with neighboring base stations to align protection subframe positions, ensuring that uplink transmissions from one cell do not interfere with downlink receptions in adjacent cells, thereby preventing interference before it occurs.
Solution Approach 2:
The patent implements periodic protection subframes at strategically determined intervals to systematically suppress interference. By regularly inserting protection subframes in a coordinated manner across neighboring cells, the system creates predictable interference-free windows that maintain data transmission efficiency while effectively managing inter-cell interference through rhythmic suppression.
Data Source
AI summary
A method and an apparatus for operating a subframe and transmitting channel information for controlling interference in a communication system are provided. If a macro evolved Node B (eNodeB) determines and reports an uplink protection subframe for suppressing uplink transmission to a neighboring eNodeB, transmits scheduling information for uplink data through a downlink subframe corresponding to an uplink protection subframe, and the uplink protection subframe determined by the neighboring eNodeB is reported, a small eNodeB sets the reported uplink protection subframe as a flexible subframe, and uses the flexible subframe for downlink transmission. If the flexible subframe is used for the downlink transmission, a terminal of the small eNodeB measures and transmits non-period channel information in the flexible subframe through at least one uplink subframe.