D2D Signal Reception Timing Alignment Using Downlink Reference
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Solution Overview
Problem
In device-to-device direct communication, user equipment in an idle state cannot acquire the timing advance configured by the base station, leading to inaccurate signal reception times and incomplete data reception.
Innovation Solution
The user equipment determines a receiving time for device-to-device direct communication signals based on a downlink timing reference time, adjusting for cyclic prefix and synchronous timing offsets to ensure accurate signal reception, regardless of its activation state relative to the other user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If user equipment in idle state uses downlink timing reference time for signal reception, then the method is simple to implement, but the signal reception time accuracy deteriorates and data reception becomes incomplete
Solution Approach 1:
The patent applies preliminary action by having the user equipment in idle state perform signal reception in advance before the calculated receiving time. The system calculates a receiving time based on downlink timing reference time and transmits the D2D signal before this time, allowing the idle user equipment to receive the signal completely without requiring real-time timing adjustment or network activation.
2Adaptability or versatility
If user equipment adjusts timing based on downlink timing reference time, then the system can operate without continuous network configuration, but the received data becomes incomplete due to timing inaccuracies
Solution Approach 1:
The system performs the signal transmission in advance before the receiving time is reached. By calculating the receiving time based on downlink timing reference time and transmitting the D2D signal beforehand, the patent ensures that user equipment in idle state can receive complete data without requiring real-time network configuration or continuous timing adjustment, thus maintaining both autonomy and data completeness.
3Measurement precision
If the system uses cyclic prefix duration for timing adjustment, then timing accuracy improves, but the complexity of timing calculation increases
Solution Approach 1:
The patent applies parameter changes by using the cyclic prefix duration as a key timing parameter. The system calculates the receiving time by adjusting the downlink timing reference time with the cyclic prefix duration, which simplifies the timing calculation while improving receiving time accuracy. This approach avoids complex multi-parameter calculations by leveraging the existing cyclic prefix structure in the signal.
Data Source
AI summary
The present application relates a signal transmission method for device to device direct communication between user equipment. A first user equipment first determines, according to a downlink timing reference time, a receiving time for receiving a device to device direct communication (D2D) signal sent by a second user equipment, and then the first user equipment receives, before the receiving time, the D2D signal sent by the second user equipment, thereby improving accuracy of a time for receiving a signal by the user equipment and ensuring completeness of received data.