LCIB Timing Source Switching for GPS Signal Loss
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Solution Overview
Problem
Low-Cost Internet Base Stations (LCIBs) deployed indoors often experience intermittent or extended loss of GPS signals, leading to desynchronization with the macro network, which can cause degraded performance in handoffs and other operations.
Innovation Solution
LCIBs are arranged to receive and decode timing information from the macro network, using macro-network timing information to calibrate their internal clock, especially when GPS signals are lost, thereby maintaining synchronization with the macro network without relying on high-reliability oscillators or valuable backhaul bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LCIBs use GPS signals as the primary timing source, then synchronization accuracy with the macro network is improved, but reliability deteriorates when GPS signals are lost in indoor deployments
Solution Approach 1:
The system changes the timing source parameter dynamically based on GPS signal availability. When GPS is available, it uses GPS timing; when GPS is lost, it switches to macro-network timing. This parameter change resolves the contradiction by adapting the timing source to environmental conditions, maintaining both accuracy and reliability.
Solution Approach 2:
The macro-network timing information acts as an intermediary backup when GPS timing is unavailable. The LCIB uses the macro-network receiver to obtain timing from macro base stations, which themselves are synchronized to GPS. This intermediary approach maintains timing reliability without requiring direct GPS reception at the LCIB.
2Stability of the object's composition
If LCIBs use high-reliability oscillators to maintain timing, then timing stability is improved, but device cost increases
Solution Approach 1:
The LCIB uses freely available macro-network timing information to calibrate its internal clock, eliminating the need for expensive high-reliability oscillators. The system services its own timing needs using existing network infrastructure, achieving timing stability without additional hardware cost.
Solution Approach 2:
The patent replaces the mechanical/physical solution of high-reliability oscillators with an electronic/software-based solution using macro-network timing reception. This substitution achieves the same timing stability function through a different mechanism that doesn't require expensive hardware components.
3Adaptability or versatility
If LCIBs use Internet connection to obtain timing information, then GPS dependency is reduced, but network bandwidth is consumed
Solution Approach 1:
The system extracts timing information directly from macro-network broadcast signals received over the air, rather than obtaining it through the Internet backhaul connection. This extraction approach provides timing flexibility without consuming valuable Internet bandwidth, as the timing data comes from a separate wireless reception path.
Data Source
AI summary
Methods and systems are provided for implementing an alternative timing source for low-cost-Internet-base-station-(LCIB) systems. In accordance with an embodiment, an LCIB has an internal clock. The LCIB is arranged to receive a GPS signal, and to treat timing information embedded in the GPS signal as the LCIB's primary source of timing information for calibrating the internal clock. The LCIB detects a loss of the GPS signal, and responsively uses a macro-network receiver to receive macro-network timing information from a macro network, which is a terrestrial wireless network. The LCIB uses the macro-network timing information to calibrate the internal clock.