D2D Inter-Carrier Discovery Gap Configuration
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Solution Overview
Problem
Current D2D communication systems in LTE networks face challenges in inter-carrier and inter-PLMN discovery, requiring assistance from the network infrastructure and lacking efficient autonomous discovery mechanisms, especially when UEs need to communicate outside their serving cellular network or across different PLMNs.
Innovation Solution
Introducing discovery gaps in the RF transmitter/receiver chain to allow UEs to autonomously discover other devices and carriers without network assistance, using network-controlled configurations to ensure reliable and efficient inter-carrier and inter-PLMN D2D communication, including scenarios without eNB coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If D2D discovery is performed autonomously by UEs without network assistance, then discovery independence and speed are improved, but reliability and coordination with cellular communications deteriorate
Solution Approach 1:
The network infrastructure acts as an intermediary by providing discovery gap configurations that enable autonomous D2D discovery while maintaining network coordination. The eNB configures specific time-frequency resources (discovery gaps) where UEs can perform D2D operations without continuous network control, balancing autonomy and reliability
Solution Approach 2:
The system dynamically switches between network-controlled and autonomous modes by using pre-configured discovery gaps. During these gap periods, UEs operate autonomously for discovery, while outside these gaps, network control is maintained, creating a dynamic hybrid operation mode
2Adaptability or versatility
If D2D communications use shared cellular radio frequency bands, then integration with cellular communications is improved, but interference management and network control complexity increase
Solution Approach 1:
The cellular spectrum is segmented into dedicated discovery gap resources and regular cellular communication resources. This segmentation allows D2D operations to occur in specific time-frequency segments without interfering with regular cellular traffic, simplifying network control while maintaining integration
Solution Approach 2:
D2D discovery operations are performed periodically during configured gap intervals rather than continuously. This periodic action reduces the time D2D signals occupy shared frequencies, minimizing interference with cellular communications while maintaining effective discovery capability
3Adaptability or versatility
If discovery gaps are introduced for inter-carrier D2D discovery, then autonomous discovery across carriers is improved, but interruption of WAN data reception occurs
Solution Approach 1:
The network pre-configures discovery gap patterns and parameters before D2D operations begin. This preliminary configuration allows UEs to anticipate and prepare for gap periods, minimizing disruption to WAN data reception by scheduling data transmissions around known gap intervals
Solution Approach 2:
The system uses minimal discovery gaps - just enough time to perform essential inter-carrier discovery operations. By using partial action (short, targeted gaps) rather than excessive action (continuous monitoring), the system achieves inter-carrier discovery capability while minimizing WAN data reception interruptions
Data Source
AI summary
A radio resource management requirement is described for a device-to-device inter-carrier discovery gap. A device to device (D2D) user equipment (UE) interruption requirement can be specified in which the interruption is not allowed. In one example, operations include receiving device-to-device (D2D) discovery data on a D2D discovery data frequency in a receive chain of a user equipment (UE) during a set of subframes, tuning the receive chain of the UE to a wireless access network (WAN) data frequency, and receiving WAN data in the receive chain of the UE on the WAN data frequency from a primary cell (PCell) during the set of subframes, wherein the D2D discovery data is received during a gap in receiving the WAN data without an interruption in the WAN data.