Inter-PLMN D2D Discovery via SIB19 Assistance
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Solution Overview
Problem
Current 3GPP LTE systems face challenges in inter-frequency and inter-PLMN device-to-device (D2D) discovery, particularly in acquiring configuration parameters, announcing and monitoring across multiple carriers, and minimizing the impact on the Uu interface, leading to unsatisfactory discovery performance.
Innovation Solution
The introduction of additional RRC signaling for inter-frequency and inter-PLMN discovery, including acquisition assistance messages, controlled announcement rates, and alignment of transmission and reception intervals, enables efficient D2D discovery across different PLMNs by configuring higher-layer parameters and utilizing demodulation reference signals dependent on PLMN identity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional D2D discovery methods are used in inter-frequency and inter-PLMN scenarios, then device discovery can be performed within the same PLMN, but discovery performance deteriorates due to inability to acquire configuration parameters from non-serving PLMNs and excessive interference across multiple carriers
Solution Approach 1:
The patent introduces an intermediary mechanism where the serving eNodeB acts as a mediator to provide assistance information about non-serving PLMN configuration parameters. Instead of requiring the UE to directly acquire complex configuration parameters from multiple non-serving PLMNs, the serving base station consolidates and provides this information through enhanced SIB19 signaling, thereby improving discovery performance while reducing device complexity
Solution Approach 2:
The patent implements preliminary action by having the serving eNodeB pre-acquire and provide assistance information about non-serving PLMN configuration parameters before the UE needs to perform inter-PLMN discovery. This includes pre-configuring discovery resource pools, announcement rates, and monitoring parameters for non-serving PLMNs, allowing the UE to perform discovery without real-time complexity of acquiring these parameters
2Productivity
If announcement rates are increased to improve discovery speed, then discovery performance improves, but interference on the Uu interface increases and resource usage becomes inefficient
Solution Approach 1:
The patent applies local quality by configuring different announcement rates for different discovery scenarios and PLMNs. Instead of using a uniform high announcement rate across all carriers and PLMNs, the system configures specific announcement rates tailored to each non-serving PLMN and frequency, allowing fast discovery where needed while minimizing interference on the Uu interface where it matters most
Solution Approach 2:
The patent implements dynamics by making announcement rates configurable and adjustable based on current network conditions, traffic load, and discovery requirements. The serving eNodeB can dynamically control the announcement rates for inter-PLMN discovery, increasing them when discovery speed is critical and decreasing them when Uu interface interference becomes problematic
3Adaptability or versatility
If multiple carriers are monitored for D2D discovery, then inter-frequency discovery capability is achieved, but device complexity increases and power consumption rises
Solution Approach 1:
The patent uses the serving eNodeB as an intermediary to provide consolidated assistance information about multiple non-serving carriers and PLMNs. The UE receives unified configuration data including carrier frequencies, discovery resource pools, and monitoring parameters for multiple carriers through enhanced SIB19, rather than having to independently discover and configure each carrier, thereby achieving inter-frequency capability while reducing device complexity
Solution Approach 2:
The patent implements universality by designing a unified configuration mechanism that handles multiple carriers and PLMNs through a single assistance information structure. The enhanced SIB19 provides universal configuration parameters that apply across multiple frequencies and PLMNs, allowing the UE to monitor multiple carriers using a consistent framework rather than requiring separate configuration procedures for each carrier
4Adaptability or versatility
If discovery configuration parameters are acquired from non-serving PLMNs, then inter-PLMN discovery is enabled, but the impact on the Uu interface increases and system performance deteriorates
Solution Approach 1:
The patent extracts the configuration parameter acquisition process from the Uu interface by providing assistance information through the serving PLMN's SIB19. Instead of requiring the UE to establish separate signaling connections with non-serving PLMNs to acquire configuration parameters, the serving base station extracts and provides this information locally, enabling inter-PLMN discovery while minimizing Uu interface overhead and energy consumption
Data Source
AI summary
A user equipment (UE) can receive, from an eNodeB, a serving PLMN system information block (SIB)19 for a carrier frequency of a serving PLMN of the UE. The UE can acquire inter-frequency and inter-PLMN discovery system information acquisition assistance signaling information from the SIB19. The UE can process a non-serving PLMN SIB19 for one or more carrier frequencies of a non-serving PLMN using the inter-frequency and inter-PLMN discovery system information acquisition assistance signaling information. The UE can identify inter-frequency and inter-PLMN discovery announcement rate information and monitoring control configuration information for the one or more carrier frequencies of the non-serving PLMN to enable the UE to perform device-to-device (D2D) discovery with a UE in the non-serving PLMN according to the inter-frequency and inter-PLMN discovery and inter-PLMN discovery announcement rate information and monitoring control configuration information.