D2D Resource Fallback Delay for Public Safety Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current public safety networks, especially those used by first responders, face challenges with direct communication when cellular coverage is unavailable, as they rely on obsolete 2G technologies, and device-to-device (D2D) communication in LTE systems lacks the ability to delay autonomous resource fallback when a UE moves out of coverage.
Innovation Solution
A method and apparatus for delaying autonomous resource fallback in D2D operations by allowing a UE to continue using in-coverage D2D resources even when out of coverage, with specific conditions such as timer-based or RSRP threshold evaluations to manage resource transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a UE autonomously changes D2D resources when moving out of coverage, then communication continuity is maintained, but resource allocation reliability deteriorates due to lack of network coordination
Solution Approach 1:
The patent implements dynamic resource allocation by allowing UEs to transition from network-controlled resource allocation in-coverage to autonomous resource selection out-of-coverage. The system dynamically adjusts the resource allocation mode based on coverage status, enabling seamless continuation of D2D communication while adapting to changing network conditions.
Solution Approach 2:
The patent applies preliminary action by having UEs pre-select and store alternative D2D resources before moving out of coverage. When coverage is lost, these pre-selected resources are immediately activated, avoiding communication interruption. This proactive approach ensures resource availability without requiring real-time network coordination out-of-coverage.
2Reliability
If a UE continues using in-coverage D2D resources out of coverage, then communication reliability is maintained, but resource conflict increases with other UEs
Solution Approach 1:
The patent implements feedback mechanisms where UEs monitor for presence indicators from other UEs using the same D2D resources. When a UE detects that another UE is using the same resources, it receives feedback through these presence indicators and autonomously switches to alternative pre-selected resources, thereby avoiding resource conflicts and interference.
Solution Approach 2:
The patent enables self-service by allowing UEs to autonomously detect resource conflicts through presence indicators and independently resolve them by switching to alternative resources without network intervention. This self-managed resource coordination mechanism reduces conflicts while maintaining communication reliability in autonomous out-of-coverage operation.
3Speed
If autonomous resource fallback is immediately triggered upon coverage loss, then resource allocation speed is improved, but communication interruption increases during transition
Solution Approach 1:
The patent applies preliminary action by pre-selecting and storing alternative D2D resources before coverage is lost. When out-of-coverage condition is detected, the UE immediately activates these pre-prepared resources without requiring time-consuming resource selection or network coordination, thereby minimizing communication interruption while maintaining fast resource allocation.
Data Source
AI summary
A method and apparatus for performing device-to-device (D2D ) transmission in a wireless communication system is provided. A user equipment (UE) determines that it is out of coverage (OOC). Even though the UE is OOC, the UE continues to perform D2D transmission by using D2D resources for in-coverage under a specific condition. Based on a specific condition, if the UE determines that is in coverage before the specific condition is met, the UE performs D2D transmission by using the D2D resources for in-coverage. If the specific condition is met while the UE is OOC, the UE performs D2D transmission by using the D2D resources for OOC.