Timing Synchronization in Ultra Dense Networks Using Intermediary Access Points
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Solution Overview
Problem
In Ultra Dense Networks (UDN), existing timing synchronization methods, such as relying on GPS, are costly and impractical for indoor deployments, especially when wireless backhaul is required, as they do not provide a straightforward means for synchronization without the need for additional hardware like GPS antennas and receivers.
Innovation Solution
The method utilizes existing overlapping networks as external timing reference sources, where root timing reference APs derive and propagate reference timing to neighboring APs, eliminating the need for all APs to directly derive the reference timing, thereby reducing deployment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS synchronization is used for timing synchronization in UDN, then synchronization accuracy is improved, but deployment cost increases due to requiring GPS antennas and receivers at every AP
Solution Approach 1:
The patent introduces existing networks (such as mobile communication networks) as intermediary timing reference sources. Root timing reference APs that can access these existing networks derive timing information from them and propagate it to neighboring APs. This intermediary approach eliminates the need for direct GPS reception at every AP while maintaining synchronization accuracy through the hierarchical propagation mechanism.
Solution Approach 2:
The patent segments the synchronization function into two parts: root timing reference APs that directly obtain timing from external sources (existing networks or GPS), and non-root timing reference APs that derive timing from root APs. This segmentation allows most APs to use lower-cost wireless derivation while only requiring a few root APs to have full synchronization capabilities, thereby reducing overall deployment cost while maintaining network-wide synchronization accuracy.
2Measurement precision
If all APs directly derive reference timing from external timing reference source, then synchronization accuracy is improved, but deployment cost increases
Solution Approach 1:
The patent divides APs into root timing reference APs and non-root timing reference APs. Root APs directly derive timing from external sources, while non-root APs derive timing from root APs through wireless communication. This segmentation ensures synchronization accuracy is maintained throughout the network while significantly reducing deployment cost by eliminating the need for every AP to have direct access to external timing sources.
Solution Approach 2:
Root timing reference APs act as intermediaries between external timing reference sources and non-root timing reference APs. They receive timing information from external sources (existing networks or GPS) and propagate it wirelessly to neighboring APs, enabling cost-effective synchronization across the entire UDN without requiring direct external source access at every location.
3Adaptability or versatility
If wireless backhaul is used for UDN APs, then deployment flexibility is improved, but ability to obtain synchronization signal via wired networks is lost
Solution Approach 1:
The patent uses root timing reference APs as intermediaries that have the capability to access external timing reference sources through various means (wired or wireless). These root APs then propagate timing signals to non-root APs through wireless backhaul, enabling deployment flexibility while maintaining reliable synchronization signal acquisition across the entire network through the intermediary root APs.
Data Source
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AI summary
Disclosed are a method and an Access Point (AP) for implementing timing synchronization by one or more root timing reference APs in a radio communication network. The method comprises that each of the one or more root timing reference APs performs the following steps: selecting an external timing reference source from existing networks that at least partially overlap with the radio communication network (210); deriving a reference timing from the external timing reference source (220); and propagating the reference timing to neighboring APs in the radio communication network (230).