TDD Frame Arrangement Reporting for Downlink Interference Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In cellular wireless systems, inter-cell interference occurs when adjacent base stations operate on the same frequency but with different TDM air interface frame sequences, leading to ineffective inter-cell interference coordination (ICIC) during downlink transmissions, as the ICIC process fails to account for uplink transmission times in adjacent base stations with offset or different frame structures.
Innovation Solution
A method where a user equipment (UE) served by a base station on a TDM air interface determines the TDM frame arrangement of an adjacent base station and reports it to the serving base station, allowing the serving base station to avoid scheduling downlink transmissions during the adjacent base station's uplink times, thereby minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inter-cell interference coordination (ICIC) is implemented between adjacent base stations operating on the same frequency, then downlink transmission reliability is improved, but the system cannot account for uplink transmission times in adjacent base stations with offset or different frame structures, leading to incomplete interference mitigation
Solution Approach 1:
The patent implements feedback by having user equipment (UE) report the TDD frame arrangement of adjacent base stations to the serving base station. This feedback mechanism enables the serving base station to adapt its downlink transmissions based on the actual frame structures of neighboring cells, resolving the contradiction between maintaining reliable downlink transmissions and adapting to diverse frame structures in adjacent base stations.
Solution Approach 2:
The patent introduces dynamic adjustment of downlink transmission scheduling based on reported TDD frame arrangements. Instead of using a fixed ICIC approach, the system dynamically modifies transmission timing to avoid interfering with uplink transmissions in adjacent cells, thereby achieving both reliability and adaptability to different frame structures.
2Ease of operation
If base stations use fixed TDM frame structures for downlink and uplink transmissions, then system operation is simplified, but interference occurs when adjacent base stations have offset or different frame sequences causing downlink transmissions to overlap with uplink transmissions
Solution Approach 1:
The patent applies preliminary action by having user equipment report the TDD frame arrangement of adjacent base stations before the serving base station schedules downlink transmissions. This advance knowledge allows the serving base station to proactively avoid scheduling downlink transmissions during times when adjacent base stations are performing uplink transmissions, preventing interference before it occurs.
Solution Approach 2:
The patent changes the scheduling parameter of downlink transmissions based on the reported TDD frame arrangement of adjacent base stations. By adjusting the timing parameter of downlink transmissions to avoid overlap with adjacent uplink transmissions, the system maintains simple fixed frame structures while eliminating interference through parameter modification.
3Reliability
If user equipment reports TDD frame arrangement of adjacent base stations, then downlink transmission scheduling can be optimized to avoid interference, but additional signaling overhead and processing are required
Solution Approach 1:
The patent applies self-service by utilizing existing uplink transmission resources to carry the report of the TDD frame arrangement. Instead of requiring separate dedicated signaling channels, the system uses the regular uplink communication between UE and base station to convey the necessary frame structure information, thereby reducing additional signaling overhead while maintaining reliable communication.
Data Source
AI summary
A method and apparatus to help mitigate interference from an adjacent coverage area. A user equipment device (UE) determines a time division duplex (TDD) frame arrangement of a neighboring base station and reports the determined TDD frame arrangement to a serving base station. The serving base station uses the reported TDD frame arrangement of the neighboring base station as a basis to avoid scheduling downlink transmission of bearer traffic to the UE at times when the TDD frame arrangement of the neighboring base station defines uplink transmission.