Wireless Communication Speed Detection Using Timing Adjustment Signals
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining communication quality during handovers between micro and macro cell base stations, especially at high speeds, due to the need for special programs and devices to detect speed, which increases cost, size, and weight, and complicates the calculation process.
Innovation Solution
A wireless communication system that uses an adjustment signal, such as SD, to estimate movement speed and select an appropriate base station, allowing for timely handovers between micro and macro cell base stations without requiring complex programs or additional devices, by calculating a bias amount from the adjustment signal and performing carrier sense to switch between base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If special programs or speed sensors are used to detect mobile station speed, then handover timing accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The base station uses its own existing timing adjustment signal (SD signal in PHS systems) to simultaneously perform two functions: adjusting data reception timing and detecting mobile station movement speed. This eliminates the need for separate speed detection programs or devices, as the system serves itself using already-transmitted signals.
Solution Approach 2:
The timing adjustment signal is given multiple functions: it continues to adjust data reception timing as before, and additionally serves as a measurement signal for detecting mobile station speed. By making this existing signal multi-functional, the patent avoids adding complex new hardware or software while improving speed detection capability.
2Measurement precision
If special programs or speed sensors are used to detect mobile station speed, then handover timing accuracy is improved, but mobile station cost and size increase
Solution Approach 1:
The base station performs speed detection using signals it already transmits, eliminating the need for speed sensors or special programs in the mobile station. This keeps the mobile station lightweight and simple while achieving accurate speed detection through the base station's processing of the timing adjustment signal.
3Loss of time
If micro cell coverage is broadened to macro cell, then handover frequency is reduced, but wireless capacity is reduced in high traffic areas
Solution Approach 1:
The system dynamically adjusts cell selection based on mobile station speed. Micro cells are used for low-speed scenarios to maximize capacity, while macro cells are used for high-speed scenarios to reduce handover frequency. This dynamic adaptation allows the system to optimize both capacity and handover performance according to actual conditions.
Solution Approach 2:
The patent changes the operational parameters by selecting different cell types (micro or macro) based on the detected speed parameter. When speed exceeds a threshold, the system transitions from micro cell to macro cell operation, effectively changing the network configuration parameter to suit the mobility condition.
4Measurement precision
If speed sensor is used to detect movement, then speed detection accuracy is improved, but calculation complexity increases
Solution Approach 1:
The base station calculates speed by analyzing the bias amount in its own timing adjustment signals, eliminating the need for complex scalar calculations from three-axis speed sensors. The calculation is simplified because the system uses the inherent timing information already present in the adjustment signals it transmits.
Data Source
AI summary
One object of the present invention is to improve stability of wireless communication, regardless of a movement speed of a mobile station by estimating a movement speed of a mobile station using a signal prepared in advance for a used standard and selecting an appropriate base station. In the wireless communication system 100 according to the present invention, in order to adjust a timing of receiving data from the PHS terminal 110 to a desired timing, base stations 120, 122 transmit an adjustment signal for advancing or delaying data transmission timing in the PHS terminal 110. Thus, the PHS terminal 110 calculates a bias amount of such an adjustment signal to determine high speed movement of the PHS terminal 110 and perform handover from a micro cell base station 120 to a macro cell base station 122.