FDX-TDD Coordination via Propagation Delay Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The coexistence of Full-Duplex (FDX) and Time Division Duplex (TDD) communication systems in a communication network impacts the reach of G.fast lines due to the need to accommodate propagation delay and cyclic extension, leading to inefficiencies in synchronization and signal interference.
Innovation Solution
A method and apparatus that coordinate communications by using distinct cyclic prefix and suffix structures for FDX and TDD symbols, with a reference time point determined by propagation delays, allowing for synchronized transmission without impacting the reach of TDD lines, ensuring proper alignment and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FDX and TDD systems coexist in the same communication network, then network versatility and adaptability are improved, but the reach of G.fast lines is reduced due to propagation delay accommodation requirements
Solution Approach 1:
The communication network is segmented into distinct FDX and TDD subsystems with separate synchronization mechanisms. FDX lines use timing advance parameters for full-duplex operation while TDD lines use separate time slots, allowing each subsystem to be optimized independently without compromising the reach of G.fast lines.
Solution Approach 2:
Different synchronization strategies are applied locally to different line types. FDX lines receive timing advance adjustments tailored to their specific propagation delays, while TDD lines use fixed time slot allocations. This localized optimization ensures that FDX coexistence does not uniformly reduce TDD reach.
2Measurement precision
If cyclic extension is increased to accommodate propagation delay in FDX lines, then synchronization accuracy is improved, but the available time for data transmission is reduced
Solution Approach 1:
The cyclic extension is segmented into two functional parts: a cyclic prefix for accommodating delay spread and a cyclic suffix for accommodating propagation delay. This segmentation allows precise synchronization without requiring excessive total extension, thereby preserving data transmission time.
Solution Approach 2:
The timing advance parameter is dynamically adjusted based on measured propagation delays to optimize the balance between cyclic extension length and data transmission time. This parameter optimization ensures sufficient synchronization accuracy while minimizing time loss.
3Productivity
If timing advance is applied to synchronize FDX symbols, then transmission rate is improved, but interference from propagation delay variations increases
Solution Approach 1:
The timing advance mechanism, which initially compensates for propagation delay, is enhanced to also provide interference cancellation. By adjusting the timing advance parameter, the system converts propagation delay variations from harmful interference into beneficial synchronization cues, thereby improving transmission rate while reducing interference.
Solution Approach 2:
A feedback mechanism continuously monitors interference levels and adjusts timing advance parameters accordingly. This closed-loop control optimizes the balance between transmission rate and interference cancellation, adapting to varying propagation conditions in real-time.
Data Source
AI summary
The method includes transmitting by a first remote communication unit an upstream symbol with a first structure onto a first communication line at a reference time point trf, wherein the reference time point trf is determined based on a time of reception of a downstream symbol with the first structure tFDX_DS_RX and a first propagation delay over the first communication line tPD1, as trf=tFDX_DS_RX−tPD1; transmitting by a second remote communication unit an upstream symbol with a second structure onto the second communication line at tTDD_US_TX=trf−tPD2 during a time interval assigned for upstream transmission on the second communication line, wherein tPD2 is a second propagation delay over the second communication line, so that the upstream symbol with the second structure transmitted by the second remote communication unit arrives at the access node at the reference time point trf.