Common Time Reference for D2D Synchronization
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Solution Overview
Problem
In communications networks, especially in device-to-device (D2D) communications, existing methods for deriving common time references are complicated by network topology changes and are not compatible across different cells, leading to timing discontinuities and synchronization issues.
Innovation Solution
A method and device for obtaining an adjustment term based on communications from the network to set a common time reference for devices, which is independent of network topology, allowing improved synchronization in D2D communications by using a one-way propagation delay between devices and base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downlink or uplink timing is used to derive time references in D2D communications, then time alignment can be achieved within a single cell, but timing compatibility is lost across different cells due to network topology changes
Solution Approach 1:
The invention introduces a common reference time (T_ref) as an intermediary that is independent of any specific base station's downlink or uplink timing. This reference time acts as a mediator that allows devices in different cells to establish compatible time references for D2D communications, resolving the conflict between local time alignment precision and cross-cell compatibility.
Solution Approach 2:
The invention segments the time reference establishment process into two independent components: (1) derivation of a common reference time T_ref that is independent of network topology, and (2) calculation of device-specific time references using propagation delay compensation. This segmentation allows each component to be optimized independently, achieving both precision and compatibility.
2Reliability
If base station timing is used for D2D communications, then devices can synchronize to their serving base station, but timing discontinuities occur when devices move between cells or when base stations have different time references
Solution Approach 1:
The invention creates a universal time reference T_ref that serves all base stations and devices uniformly, independent of which base station a device is currently served by. This universal reference ensures that time references remain continuous and compatible across cell boundaries, eliminating timing discontinuities when devices move between cells.
Solution Approach 2:
The invention changes the fundamental parameter used for time reference derivation from base station-specific timing (which varies between cells) to a common reference time T_ref that is consistent across the entire network. This parameter change ensures stability and continuity of time references even as network topology changes.
3Ease of operation
If devices derive time references from their serving base station, then local communication can be synchronized, but devices out of coverage cannot establish valid time references
Solution Approach 1:
The invention enables devices to autonomously calculate their own time references using the common reference time T_ref and their measured propagation delays to base stations. This self-service mechanism allows devices to establish valid time references independently, whether they are in coverage or out of coverage, without requiring continuous base station signaling.
Data Source
AI summary
A device operates in a communications network by obtaining an adjustment term based on communications from the communications network and setting a time reference for the device based on the obtained adjustment term. The adjustment term is such that the set time reference for the device is common to at least one other device in communication with the device. The device further operates by communicating with the at least one other device in device-to-device communication, based on the common set time reference.