Distributed Unit Clock Synchronization via Radio Units
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Solution Overview
Problem
In wireless communication networks, particularly in 5G RANs, distributed units often lack access to precise timing information, leading to clock drift issues that result in missed timeslots and poor user experiences due to 'dead air' and packet loss, as they rely on internal clocks or networked time servers without GPS signals, which are unreliable.
Innovation Solution
Implementing techniques for the distributed unit to synchronize its clock with radio units using initial and ongoing time synchronization methods, minimizing bandwidth usage, and managing workload to ensure timely data transmission, including requesting timing information from radio units, applying correction factors, and adjusting synchronization frequency based on clock drift and workload conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If distributed units rely on internal clocks or networked time servers without GPS signals, then device complexity is reduced, but timing precision deteriorates leading to clock drift
Solution Approach 1:
The patent introduces radio units as intermediary devices that have GPS capability and act as timing mediators between GPS satellites and distributed units. The radio units receive precise timing from GPS and forward it to distributed units through the air interface, eliminating the need for distributed units to have direct GPS access while maintaining timing precision.
Solution Approach 2:
The patent replaces the traditional GPS receiver hardware in distributed units with a software-based timing synchronization mechanism that receives timing information via radio signals. This substitution allows distributed units to achieve GPS-level timing precision without requiring GPS hardware, reducing device complexity.
2Measurement precision
If distributed units synchronize clocks frequently with radio units, then timing precision is improved, but bandwidth consumption increases
Solution Approach 1:
The patent implements dynamic synchronization where the timing synchronization frequency and method are adapted based on current conditions. The system can switch between different synchronization modes (e.g., frequent exchanges vs. correction factor application) depending on workload, clock drift rates, and radio unit availability, optimizing the balance between precision and bandwidth usage.
Solution Approach 2:
The patent changes the parameter of synchronization frequency based on system state. Instead of fixed periodic synchronization, the system adjusts synchronization intervals and methods dynamically, using correction factors for minor adjustments and full synchronization only when necessary, thereby reducing overall bandwidth consumption while maintaining precision.
3Reliability
If distributed units manage workload to prevent missing timeslots, then reliability is improved, but productivity decreases due to workload reduction
Solution Approach 1:
The patent applies preliminary action by proactively managing workload before timeslot deadlines are approached. The system monitors workload trends and preemptively reduces or redistributes tasks to ensure timely completion, preventing missed timeslots while minimizing the impact on overall productivity through intelligent task management rather than blanket workload reduction.
Data Source
AI summary
Systems and methods are described for implementing a distributed unit in a radio access network that synchronizes its clock with a radio unit. A distributed unit may be deployed in a location where it cannot receive timing information from a satellite or may lack the equipment to obtain and process satellite signals. The clock of the distributed unit may thus drift relative to the clocks of the radio units, which may cause the distributed unit to mistime its transmissions of data to radio units for delivery to user devices. The distributed unit may prevent clock drift by obtaining timing information from the radio units, determining an amount of clock drift that is occurring, and applying a correction factor to keep the distributed unit clock synchronized with the radio unit clock. The distributed unit may determine how often to synchronize based on the severity and variability of the clock drift.