D2D Resource Allocation via RRC State Detection
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Solution Overview
Problem
Current D2D communication systems face challenges in accurately detecting network coverage, leading to potential interference with LTE networks, especially when D2D services share the same frequency band as LTE cellular services, and require efficient methods to determine whether a wireless terminal is in or out of network coverage, particularly in Idle Mode.
Innovation Solution
The solution involves utilizing existing wireless terminal state information, specifically the RRC Idle Mode states, to determine network coverage without requiring new signal power measurements, and switching between network-allocated and pre-configured resource modes based on coverage status to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If D2D communication uses the same frequency band as LTE cellular services, then spectrum utilization is improved, but network interference increases
Solution Approach 1:
The patent applies preliminary action by performing network coverage detection and determining coverage status before initiating D2D communication resource allocation. The terminal device determines whether it is in network coverage before selecting between network-allocated and autonomous resources, preventing interference issues before they occur. This is evident in the method steps where coverage status determination precedes resource selection mode decision.
Solution Approach 2:
The patent implements dynamics by enabling the terminal device to dynamically switch between two resource allocation modes (network-allocated mode and autonomous mode) based on real-time network coverage status. When in coverage, the terminal uses network-allocated resources; when out of coverage, it switches to autonomous resources. This dynamic adaptation allows the system to optimize spectrum utilization while minimizing interference by adjusting resource allocation strategy according to network conditions.
2Measurement precision
If new signal power measurements are implemented to detect network coverage, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by utilizing existing RRC Idle Mode state information that the terminal device already maintains for cellular network operations. Instead of implementing new measurement mechanisms, the invention leverages the terminal's existing state machine and network protocols to determine coverage status. The terminal uses its existing RRC state transitions and network interaction capabilities to infer coverage status, eliminating the need for additional measurement hardware or complex new measurement procedures.
Solution Approach 2:
The patent implements universality by making the existing RRC Idle Mode state information serve a dual purpose: both for traditional cellular network operations and for D2D communication resource allocation decisions. The same state information that manages cellular connectivity is also used to determine whether the terminal is in coverage for D2D purposes, eliminating the need for separate measurement systems and reducing overall device complexity.
3Productivity
If network-allocated resources are used for D2D communication, then resource allocation efficiency is improved, but network control overhead increases
Solution Approach 1:
The patent implements dynamics by creating a dynamic resource allocation framework that switches between network-allocated mode and autonomous mode based on terminal coverage status. When terminals are in network coverage, the system uses network-allocated resources with centralized control for optimal resource allocation efficiency. When terminals move out of coverage, the system dynamically transitions to autonomous mode where terminals self-select resources from pre-configured pools, eliminating the need for continuous network control signaling and reducing network overhead.
Solution Approach 2:
The patent applies segmentation by dividing the D2D resource allocation space into two distinct segments: network-allocated resources for in-coverage terminals and autonomous resources for out-of-coverage terminals. This segmentation allows the network to maintain efficient centralized control for terminals within coverage while enabling autonomous operation for terminals outside coverage, thereby optimizing the trade-off between allocation efficiency and control overhead for different operational scenarios.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A node (22) of a radio access network which communicates with a wireless terminal (26i) over a radio interface (24) and sends to the wireless terminal (26i) an indication (62) which specifies, for device-to-device (D2D) communications with another wireless terminal (262), whether the wireless terminal (261) is to use network-allocated radio resources or radio resources which are selected by the wireless terminal.