Orthogonal Pilot Signal Sectors for Positioning Accuracy
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Solution Overview
Problem
Mobile stations face difficulties in accurately estimating their position due to signal interference from multiple base stations, particularly in scenarios where satellite signals are unavailable or weak, such as indoors or in tunnels, leading to the 'hearability problem' and reduced accuracy in position location estimation.
Innovation Solution
The method involves transmitting signal waveforms from multiple sectors with nearly mutually orthogonal signal dimensions, such as time or frequency, to reduce interference and enhance pilot signal detection, allowing for improved position location estimation through dedicated time slots and reuse techniques, including dedicated and time-varying coloring schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pilot signals are transmitted from multiple base stations simultaneously, then the system can provide coverage to multiple areas, but signal interference increases making position estimation inaccurate
Solution Approach 1:
The patent segments the transmission of pilot signals by assigning different time slots to different base stations. Each base station transmits its pilot signal in a dedicated time slot, preventing simultaneous transmissions and reducing interference. This time-division approach allows the mobile station to receive clear pilot signals from multiple base stations sequentially, improving position estimation accuracy.
Solution Approach 2:
The patent implements periodic transmission of pilot signals where each base station transmits its pilot signal in alternating time slots. This periodic action pattern ensures that pilot signals are transmitted regularly but not simultaneously, creating a rhythm of transmission that reduces interference while maintaining system coverage and reliability.
2Measurement precision
If the mobile station receives pilot signals from multiple base stations, then position location capability is enabled, but the hearability problem reduces detection accuracy
Solution Approach 1:
The patent segments the time domain into different slots for different base stations. By assigning unique time slots to each base station's pilot signal transmission, the mobile station can detect and measure each signal clearly without interference from simultaneous transmissions. This segmentation resolves the hearability problem by ensuring clear detection of each base station's pilot signal.
Solution Approach 2:
The patent implements preliminary time slot assignment where the scheduling of pilot signal transmissions is predetermined. The mobile station knows in advance which time slots correspond to which base stations, allowing it to prepare for optimal signal detection. This preliminary organization of transmission timing improves the mobile station's ability to detect and measure pilot signals accurately.
3Area of stationary object
If multiple base stations transmit pilot signals simultaneously, then system coverage is maximized, but the near-far effect causes reduced signal discrimination
Solution Approach 1:
The patent segments the transmission timeline so that different base stations transmit in different time slots. This segmentation allows the system to maintain wide coverage by having multiple base stations active at different times while preventing the near-far effect by ensuring that only one base station transmits at a time, making signal discrimination accurate regardless of distance.
Solution Approach 2:
The patent uses periodic time-division transmission where base stations alternate their pilot signal transmissions. This periodic action pattern allows the system to cover large areas with multiple base stations while maintaining signal discrimination accuracy, as each base station's signal is transmitted periodically without simultaneous interference from other base stations.
Data Source
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AI summary
Briefly, in accordance with one embodiment, a method of transmitting signals is provided. Signal waveforms are transmitted from at least two respective sectors. The at least two respective sectors are from at least two different sets of a superset of sectors. The transmitted signal waveforms include signal waveforms at least nearly mutually orthogonal at least along a particular signal dimension. An advantage of such an embodiment, for example, is reduced signal interference.