D2D Subframe Pattern Scheduling for Resource Utilization
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Solution Overview
Problem
In device-to-device (D2D) communication systems, user equipment (UEs) with a single reception chain face performance degradation due to unnecessary waste of downlink resources, as they must switch between cellular and D2D reception, and traditional methods avoid scheduling downlink transmissions in D2D reception subframes, leading to inefficient resource utilization.
Innovation Solution
The UE determines a pattern of D2D reception subframes and reports it to the base station, allowing the base station to avoid scheduling downlink transmissions in subframes where D2D reception is not monitored, and optionally modify the subframe pattern to add additional D2D reception subframes, enabling flexible switching between cellular and D2D reception without performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station avoids scheduling downlink transmissions in all D2D reception subframes to prevent conflicts, then D2D reception reliability is improved, but downlink resource utilization deteriorates
Solution Approach 1:
The patent segments the D2D reception subframes into two categories: those where the UE actually monitors D2D signals and those where it does not. By dividing the originally uniform set of D2D reception subframes into these distinct groups, the system can apply different scheduling strategies to each segment, allowing downlink transmissions in subframes where D2D monitoring does not occur while maintaining reliability in subframes where it does.
Solution Approach 2:
The patent introduces dynamic reporting mechanisms where the UE informs the base station about its actual D2D monitoring patterns. This dynamic feedback allows the base station to adaptively adjust downlink scheduling decisions based on real-time UE behavior, transforming the static resource allocation into a dynamic system that optimizes both reliability and resource utilization.
2Ease of operation
If the UE switches between cellular reception and D2D reception in TDM manner, then single reception chain limitation is addressed, but downlink performance deteriorates due to resource waste
Solution Approach 1:
The patent implements feedback mechanisms where the UE reports its D2D monitoring patterns to the base station. This feedback enables the base station to make informed scheduling decisions, allowing it to allocate downlink resources in subframes where the UE will not be monitoring D2D signals, thereby improving downlink performance while the UE continues to operate with a single reception chain through TDM switching.
3Productivity
If the base station schedules downlink transmissions in D2D reception subframes, then downlink resource utilization is improved, but reception conflicts occur
Solution Approach 1:
The patent applies preliminary action by having the UE report its D2D monitoring patterns to the base station before downlink scheduling decisions are made. This advance information allows the base station to proactively avoid scheduling downlink transmissions in subframes where conflicts would occur, while freely utilizing subframes where no D2D monitoring takes place, thus achieving both high resource utilization and reception reliability.
Data Source
AI summary
This disclosure generally relates to downlink transmission scheduling for D2D UE based on subframe pattern. In one embodiment, the D2D UE may provide the BS with information on a pattern of the D2D reception subframes that indicates the usage of at least some of the D2D reception subframes. From the pattern, the BS may determine one or more D2D reception subframes in which the UE wants to monitor the D2D reception and/or the cellular reception. Then the BS may avoid scheduling the downlink transmission in the subframes in which the UE monitors the D2D reception. In the other D2D reception subframes, the downlink transmission can be scheduled. In this way, the UE can properly switch between the D2D reception and cellular reception, without any conflicts or downlink resource waste.