Inter-Frequency D2D Discovery via Downlink Skipping
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Solution Overview
Problem
In wireless communication systems, devices (UEs) face challenges in performing device-to-device (D2D) discovery procedures when operating on different frequencies and carriers, as it disrupts communication with the serving base station, especially during active communication sessions.
Innovation Solution
A monitoring UE informs the serving base station of its intention to perform a discovery scan on a different frequency, allowing it to skip certain downlink transmissions, enabling inter-frequency and inter-carrier D2D discovery procedures by transmitting information associated with the target frequency and determining the capability to autonomously skip downlink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a monitoring UE tunes to a different frequency to detect D2D discovery signals, then D2D discovery capability is improved, but communication with the serving base station is disrupted
Solution Approach 1:
The patent divides the operation into distinct time segments: discovery scan intervals and cellular communication intervals. During discovery scan intervals, the UE temporarily suspends cellular downlink reception to tune to D2D frequencies, while during cellular intervals, it focuses on base station communication. This temporal segmentation resolves the contradiction by ensuring both functions operate at different times rather than simultaneously competing for the same radio resources.
Solution Approach 2:
The patent implements dynamic switching between cellular and D2D operating modes based on scheduled discovery scan intervals. The UE dynamically adjusts its frequency tuning and reception behavior according to pre-configured discovery scan patterns, allowing it to be adaptive in pursuing D2D discovery while maintaining scheduled cellular communication. This dynamic approach enables the system to balance both objectives rather than being static in one mode or the other.
2Area of stationary object
If the monitoring UE performs discovery scan on inter-frequency, then D2D discovery range is improved, but downlink transmissions from base station are skipped
Solution Approach 1:
The patent applies preliminary action by pre-configuring discovery scan intervals and patterns before the UE begins D2D discovery operations. The base station provides the UE with advance knowledge of when discovery scans will occur, allowing the UE to pre-schedule its frequency switching and downlink reception suspension. This preliminary planning enables the UE to systematically skip only specific downlink transmissions during predetermined discovery intervals while maintaining normal downlink reception at other times, thus limiting information loss to only what is necessary for discovery operations.
3Productivity
If the UE autonomously skips downlink transmissions during discovery scan, then D2D discovery efficiency is improved, but coordination with base station is reduced
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously manage its own frequency switching and downlink reception suspension during discovery scan intervals based on pre-configured parameters. Rather than requiring real-time coordination or approval from the base station for each frequency switch, the UE independently executes discovery scans according to its configured schedule, only needing to inform the base station of its discovery intentions. This self-service approach significantly improves D2D discovery efficiency by reducing coordination overhead and latency while maintaining adequate base station awareness through simplified signaling.
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AI summary
Methods, systems, and devices are describe for signaling protocols for device-to-device discovery operations in a wireless communication system. A user equipment (UE) may be communicating with a serving base station using a first frequency in a first frequency band. The UE may transmit, to the serving base station, information associated with performing a discovery scan procedure on a second frequency in a second frequency band during a discovery scan interval. The first frequency may be different from the second frequency. The UE may identify a capability to skip one or more downlink transmissions from the serving base station during the discovery scan interval.