D2D-Connected State for LTE Device Discovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LTE D2D communication systems face limitations in device-to-device discovery and communication, particularly in RRC-Idle and RRC-Connected states, leading to increased system overhead, power consumption, and inapplicability for devices out-of-network coverage.
Innovation Solution
Introducing a new D2D-Connected state and modifying existing RRC-Idle and RRC-Connected states to support D2D communication and discovery, allowing devices to transmit and receive D2D discovery signals without being in the RRC-Connected state, with allocated D2D IDs for efficient resource utilization and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If devices use traditional RRC-Idle or RRC-Connected states for D2D discovery, then device-to-device communication can be established, but system overhead and power consumption increase
Solution Approach 1:
The patent segments the traditional RRC states by introducing a new D2D-Connected state that is distinct from both RRC-Idle and RRC-Connected states. This segmentation allows devices to operate in a specialized state optimized for D2D discovery, separating D2D operations from traditional cellular RRC operations, thereby reducing unnecessary overhead and power consumption associated with maintaining full RRC connectivity for discovery purposes
Solution Approach 2:
The patent implements dynamic state transitions, allowing devices to flexibly move between RRC-Idle, RRC-Connected, and the new D2D-Connected states based on their current operational needs. This dynamic approach enables devices to enter the power-efficient D2D-Connected state specifically for discovery operations, rather than remaining in higher-power RRC-Connected state, thus optimizing power consumption while maintaining communication capability
2Reliability
If devices operate in RRC-Connected state for D2D discovery, then discovery signals can be transmitted, but system overhead increases
Solution Approach 1:
The patent segments the control plane by creating a dedicated D2D-Connected state that handles D2D discovery independently from the traditional RRC-Connected state. This segmentation reduces system overhead by avoiding the need to maintain full RRC protocol stacks for devices engaged only in D2D discovery, while still providing reliable discovery signal transmission through the specialized state
Solution Approach 2:
The patent extracts the D2D discovery functionality from the traditional RRC state machine by introducing a separate D2D-Connected state. This extraction allows D2D discovery operations to be performed with reduced overhead, as the device doesn't need to maintain the complete RRC-Connected state apparatus, thereby reducing system complexity while preserving discovery reliability
3Adaptability or versatility
If traditional RRC states are used for D2D communication, then cellular network coverage is maintained, but devices out-of-network coverage cannot perform D2D discovery
Solution Approach 1:
The patent makes the D2D-Connected state universal by designing it to function both within network coverage and out-of-network coverage scenarios. In-coverage devices can transition to D2D-Connected for discovery, while out-of-coverage devices can directly enter or remain in D2D-Connected state to perform discovery autonomously. This multi-functionality ensures D2D discovery availability across all coverage conditions while adapting to different network environments
Data Source
AI summary
A device is configured to perform a method of device-to-device (D2D) communication in a wireless communication network in accordance with a Long Term Evolution (LTE) standard. The method includes entering an RRC-Idle state or an RRC-Connected state. The method also includes transmitting, in the RRC-Idle state or RRC-Connected state, a D2D discovery signal for receipt by at least one second device in the network. The method further includes receiving, in the RRC-Idle state or RRC-Connected state, at least one D2D discovery signal from the at least one second device in the network.