Node Synchronization Using Stratum Flags in Communication Systems
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Solution Overview
Problem
In communication systems with multiple nodes, existing synchronization methods face challenges in handling scenarios where the stratum number exceeds the predefined limit, leading to co-channel interference and difficulties in slot allocation and identification, especially in indoor applications where GPS signals may be weak or unavailable.
Innovation Solution
A method and apparatus that determine if a node's stratum is outside a predefined set, allowing synchronization to occur differently without considering the stratum order, using a 2-bit information element to indicate stratum levels and enabling synchronization without taking the order into account, selecting the best signal quality source, and adjusting muting based on detected frame positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a 2-bit information element is used to indicate stratum levels, then signalling overhead is minimized, but stratum levels beyond 4 cannot be indicated
Solution Approach 1:
The patent extracts the stratum indication function from the 2-bit information element by introducing a separate flag (first flag) that indicates whether the stratum is within the representable range. This allows the 2-bit element to be used for normal stratum indication while the flag handles edge cases, effectively extending capability without increasing the core indication structure.
Solution Approach 2:
The patent introduces an intermediary mechanism (the first flag) that mediates between the limited 2-bit stratum indication and the need to represent unlimited strata. This flag acts as a mediator that triggers alternative handling (second flag and muting indication) when the stratum exceeds the 2-bit representation capability.
2Ease of manufacture
If predefined slot allocation scheme is used for stratums, then slot allocation is simplified, but cannot accommodate strata exceeding the indication limit
Solution Approach 1:
The patent makes the slot allocation dynamic by introducing a second flag that indicates whether the stratum has exceeded the predefined set. This allows the system to adaptively adjust slot allocation behavior based on the stratum level, maintaining simplicity for common cases while enabling flexibility for edge cases through the muting indication mechanism.
3Measurement precision
If multi-hop synchronization is implemented, then synchronization accuracy is improved, but co-channel interference increases due to asynchronised operation
Solution Approach 1:
The patent implements feedback mechanisms through the flag system that monitors stratum levels and provides instructions for muting transmissions. This feedback loop allows nodes to detect when they are in a stratum that would cause interference and automatically adjust their transmission behavior, thereby reducing co-channel interference while maintaining synchronization accuracy.
4Reliability
If GPS-based synchronization is used, then synchronization reliability is improved, but device complexity increases and GPS signals may be unavailable in indoor applications
Solution Approach 1:
The patent creates a universal synchronization mechanism that works across multiple strata and deployment scenarios without requiring GPS receivers. The flag-based stratum indication system provides a common reference framework that can be implemented in any node, making the system universally applicable whether GPS is available or not, and whether nodes are in indoor or outdoor locations.
Data Source
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AI summary
Synchronisation in a communication system A method and apparatus for a communication system is disclosed. In the system communications occur via a multiple of nodes each providing a stratum for synchronisation. It is determined that the stratum of a node is not included in a predefined set of stratums. In response to said determination synchronising with the node is provided differently from nodes with stratums in the predefined set of stratums without taking the order of the stratum into account. Information about the status can be communicated between nodes.