Access Point Frame Alignment for Multi-Source DAS and RAN Timing
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Solution Overview
Problem
Existing distributed antenna systems (DAS) and radio access networks (RAN) face challenges in synchronizing multiple timing sources, leading to computational inefficiencies and delays in decoding base station configurations, especially when serving multiple wireless operators with different timing profiles.
Innovation Solution
A system for synchronizing multiple timing sources at an access point or radio unit, aligning OTA frames, subframes, slots, and symbols to a common frame boundary timing, using protocols like PTP and SyncE, and employing buffers to handle packet-based sources, enabling synchronization across RF and packet-based sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple base station sources with different OTA frame boundary timing are served simultaneously, then the coverage area and service capability are improved, but the computational overhead and complexity of synchronization increase
Solution Approach 1:
The patent introduces a master unit as an intermediary between multiple base station sources and access points. The master unit receives timing information from multiple base station sources, processes and synchronizes this timing information, then distributes the synchronized timing to access points. This intermediary structure simplifies the synchronization complexity by centralizing the timing coordination function, allowing the system to serve multiple operators with different timing profiles without each access point needing to independently handle complex multi-source synchronization.
2Reliability
If frame alignment processing is performed for multiple timing sources, then the wireless service continuity is improved, but the computational overhead increases
Solution Approach 1:
The patent segments the frame alignment processing into two distinct stages: (1) The master unit performs initial frame alignment by adjusting the timing of received frames from multiple base station sources to create a common reference timing, and (2) Access points perform subsequent frame alignment by synchronizing to the master unit's timing. This segmentation distributes the computational workload, preventing any single component from bearing the full burden of processing multiple timing sources, thereby reducing overall computational overhead while maintaining service continuity.
Solution Approach 2:
The master unit performs preliminary frame alignment processing by pre-synchronizing timing information from multiple base station sources before distributing it to access points. This preliminary action ensures that access points receive already-aligned timing data, significantly reducing their computational burden. The master unit's advance processing of timing synchronization creates a standardized reference that simplifies subsequent operations at access points, thereby reducing total computational overhead while ensuring reliable service continuity.
3Productivity
If rapid decoding of base station configurations is achieved through synchronization, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The master unit performs preliminary synchronization by pre-aligning timing information from multiple base station sources and distributing the synchronized timing to access points before actual data decoding occurs. This preliminary timing alignment ensures that when access points receive framed data, the frames are already synchronized to a common boundary, enabling immediate and rapid decoding without requiring complex real-time synchronization during the decoding process itself.
Solution Approach 2:
The master unit acts as an intermediary that centralizes the complex timing synchronization function, separating it from the data decoding function performed by access points. This intermediary structure allows access points to focus on rapid decoding of already-synchronized data, while the master unit handles the complexity of multi-source timing alignment. The separation of concerns enables fast decoding at access points without each unit needing to implement complex synchronization logic.
Data Source
AI summary
One embodiment is a system having a master unit coupled to first and second base station sources having different OTA frame boundary timings, where an access point coupled to the master unit receives fronthaul data for the first and second base station sources, determines a common OTA frame boundary timing, and aligns OTA symbols and frames for the first and second base station sources to the common OTA frame boundary timing. Another embodiment is a system having a base station synchronized with a timing grandmaster and a master unit, synchronized with the timing grandmaster, coupled to the base station. The master unit determines the time of day using the synchronization, identifies a system frame and subframe number using the time of day, acquires configuration information for communications with the base station using the system frame and subframe number, and identifies frame boundary timing using the configuration information.