Half Duplex Uplink Downlink Synchronization Timing Advance
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Solution Overview
Problem
In half-duplex communication systems, the over-dimensioning of idle periods leads to a significant reduction in effective transmission duration, and the existing timing advance mechanisms do not adequately synchronize uplink sub-frames, resulting in inefficiencies and reduced coverage.
Innovation Solution
A method that involves defining a single idle period equal to the summation of downlink/uplink and uplink/downlink required minimum idle durations, with an incremental timing advance value to synchronize uplink sub-frames, allowing for efficient communication and increased coverage by optimizing idle period placement and timing alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate idle periods are defined between downlink/uplink and uplink/downlink sub-frames, then interference between sub-frames is avoided, but the effective transmission duration is significantly reduced
Solution Approach 1:
The patent merges the downlink/uplink idle period and uplink/downlink idle period into a single common idle period positioned between the downlink sub-frame and uplink sub-frame. This consolidation maintains the interference avoidance function while eliminating redundant idle periods, thereby increasing the effective transmission duration.
Solution Approach 2:
The patent introduces a timing advance mechanism that performs preliminary timing adjustment for uplink sub-frames. By advancing the uplink transmission timing, the system can reduce the required idle period duration while still ensuring proper separation between downlink and uplink transmissions, thus resolving the contradiction between interference avoidance and transmission efficiency.
2Ease of operation
If traditional timing advance mechanisms are used, then uplink sub-frames can be transmitted, but synchronization is insufficient and coverage is limited to effective cell radius
Solution Approach 1:
The patent employs a feedback mechanism where the base station measures the actual arrival time of uplink sub-frames and adjusts the timing advance value accordingly. This closed-loop feedback enables precise synchronization of uplink sub-frames from multiple user equipments, extending reliable communication beyond the effective cell radius.
Solution Approach 2:
The patent makes the timing advance value dynamic by allowing it to vary based on the specific user equipment and channel conditions. This dynamic adjustment enables the system to maintain synchronization accuracy for user equipments at different distances from the base station, thereby expanding coverage beyond the fixed effective cell radius.
3Adaptability or versatility
If idle periods are over-dimensioned to accommodate all user equipments, then coverage is maximized, but spectral efficiency is significantly reduced
Solution Approach 1:
The patent applies local quality by customizing the timing advance value for each user equipment based on its specific distance and channel conditions. This individualized approach allows the system to maximize coverage for each user without imposing a uniform over-dimensioned idle period on all users, thereby improving overall spectral efficiency.
Data Source
AI summary
A method communicating downlink and uplink sub-frames between a base and at least one half duplex user equipment. For a scheduled synchronization time, beginning of reception of an effective part of the uplink sub-frame is separated from end of transmission of an effective part of the first downlink sub-frame by a duration of the difference between a single idle period and an incremental timing advance value. The single idle period, having a duration greater than or equal to summation of downlink/uplink and uplink/downlink required minimum idle durations, is reserved in the end of the first downlink sub-frame or the beginning of the uplink sub-frame, or both. The incremental timing advance value is greater than or equal to the uplink/downlink required minimum idle duration and lower than or equal to the difference between the duration of the single idle period and the downlink/uplink required minimum idle duration.