TDD Time Slot Offset Determination for Interference Mitigation
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Solution Overview
Problem
The co-location of LTE-TDD and TD-SCDMA systems in adjacent channel frequencies leads to serious interference due to misalignment of time slots, which affects transmission efficiency and coverage.
Innovation Solution
A method and system for determining a time slot offset by synchronizing the first TDD system with the second TDD system, aligning the uplink-to-downlink switch points to eliminate interference, involving a matching module for synchronization and an offset determination module to calculate the time slot offset based on the time difference between the systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LTE-TDD and TD-SCDMA systems are co-located in adjacent channel frequencies with independent time slot configurations, then each system can operate independently with its own frame structure, but serious interference occurs due to misalignment of uplink-to-downlink switch points
Solution Approach 1:
The patent introduces a synchronization mechanism as an intermediary between LTE-TDD and TD-SCDMA systems. The base station determines time slot offsets by synchronizing with the TD-SCDMA system's frame structure, using its timing as a reference to align uplink-to-downlink switch points. This mediator approach allows both systems to operate independently while maintaining coordinated timing to avoid interference.
Solution Approach 2:
The patent changes the timing parameter of LTE-TDD time slots by introducing an offset value. The base station calculates the offset based on the time difference between LTE-TDD and TD-SCDMA frame structures, then applies this offset to adjust LTE-TDD uplink-to-downlink switch points. This parameter modification ensures alignment with TD-SCDMA timing while preserving LTE-TDD's independent operation.
2Object-affected harmful factors
If the uplink-to-downlink switch points are aligned between LTE-TDD and TD-SCDMA systems, then interference is reduced, but the time slot configuration becomes constrained by the need for synchronization
Solution Approach 1:
The patent performs preliminary synchronization action by determining the time slot offset before actual data transmission begins. The base station calculates the offset based on TD-SCDMA frame structure parameters and applies it in advance to configure LTE-TDD time slots. This preliminary alignment reduces interference without requiring complex real-time synchronization mechanisms during operation.
3Object-affected harmful factors
If the time slot offset is determined based on TD-SCDMA frame structure, then LTE-TDD can align with TD-SCDMA timing, but flexibility in LTE-TDD time slot configuration is reduced
Solution Approach 1:
The patent implements dynamic time slot configuration by allowing the offset value to be adjusted based on different TD-SCDMA frame structures and deployment scenarios. The base station can determine different offset values for different cell configurations, maintaining alignment with TD-SCDMA while adapting to specific network requirements. This dynamic approach preserves flexibility despite the synchronization constraint.
Data Source
AI summary
A method for determining a data transmission offset includes: synchronizing a first time division duplex TDD system with a second TDD system (a500); determining a transmission timing advance of a user terminal according to a deviation between random access time and desired time of the user equipment during establishing the uplink synchronization of the second TDD system (a501); determining an offset of a time slot of the second TDD system according to a time difference between the time slots of the first TDD system and the second TDD system (a502); and obtaining a data transmission offset of the time slot by adding the determined offset of the time slot to the determined transmission timing advance (a503). A system and a base station for determining a data transmission offset are provided.