D2D Wireless Terminal Coverage Detection and Resource Allocation
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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 when D2D services share the same frequency band, and existing methods are complex and inefficient, especially for wireless terminals in Idle Mode.
Innovation Solution
The method involves a wireless terminal using pre-configured D2D radio resources for communication when out-of-coverage, determined through RRC Idle Mode state transitions and a counter-based system, to avoid network interference and ensure efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D communication uses the same frequency band as LTE network, then resource utilization is improved, but network interference increases
Solution Approach 1:
The system performs preliminary detection of network coverage status before initiating D2D communication. The wireless terminal detects whether it is in-coverage or out-of-coverage of the LTE network, and based on this detection result, selectively activates D2D communication on the same frequency band only when appropriate (out-of-coverage), thereby utilizing frequency resources efficiently while preventing network interference
Solution Approach 2:
Instead of allowing D2D communication to operate continuously on the same frequency band as LTE (which would cause interference), the system inverts the approach by enabling D2D communication only when the terminal is out-of-coverage of the LTE network. This conditional activation based on inverted logic (enable when NOT in-coverage) resolves the interference issue while maintaining resource utilization benefits
2Measurement precision
If complex coverage detection methods are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The wireless terminal uses its existing RRC Idle Mode state transition mechanisms and cell selection/reselection procedures to self-determine coverage status. The terminal leverages already-available system information blocks (SIBs) and standard cell selection criteria to detect whether it is in-coverage or out-of-coverage, without requiring additional complex detection hardware or sophisticated algorithms. This self-service approach achieves accurate coverage detection while minimizing device complexity
Data Source
Figure 1A
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Figure 1C
AI summary
As a result of the selection/reselection operation, a wireless terminal (26) selects the high priority candidate frequency for use in the device-to-device (D2D) communications. During the cell selection/reselection operation, the wireless terminal (26) is required to consider selection/reselection candidate frequencies at which the wireless terminal (26) cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal (26) is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to- device (D2D) supported frequencies. In another basic mode predefined RRC Idle Mode state transition(s) are used to determine when a wireless terminal (26) encounters an out-of-coverage situation for device-to-device (D2D) communications purposes; and when the out-of-coverage situation is determined, the wireless terminal (26) uses pre-configured device-to-device (D2D) radio resources for the device-to-device (D2D) communications.