Inter-Frequency Sidelink Discovery Resource Allocation
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Solution Overview
Problem
Current mobile communication systems, specifically in the 3GPP standardization project for device-to-device proximity services (D2D ProSe), lack effective methods for inter-frequency sidelink discovery transmission, as inter-frequency discovery transmission is not specified, limiting the ability of radio terminals to communicate beyond the frequency of the serving cell.
Innovation Solution
A radio terminal is configured to perform inter-frequency sidelink discovery transmission by transmitting sidelink discovery signals at a frequency different from the serving cell, receiving resource allocation information, and determining permission for such transmission based on system information blocks from both the serving cell and neighbor cells, allowing for flexible resource allocation and control modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inter-frequency sidelink discovery transmission is not specified in the standard, then the system maintains simplicity and avoids complexity in resource allocation management, but the radio terminal's ability to perform discovery communication beyond the serving cell frequency is limited
Solution Approach 1:
The patent introduces the serving cell as an intermediary that provides resource allocation information for inter-frequency sidelink discovery transmission. The serving cell acts as a mediator between the radio terminal and neighbor cells, managing resource allocation without requiring direct complex coordination between terminals and multiple frequencies. This resolves the contradiction by enabling extended frequency operation while maintaining centralized resource management simplicity.
Solution Approach 2:
The patent enables dynamic parameter changes by allowing radio terminals to transmit discovery signals on frequencies different from the serving cell frequency, controlled by resource allocation information received from the serving cell. This parameter change (frequency selection) is managed through standardized signaling mechanisms, achieving versatility without proportionally increasing system complexity.
2Reliability
If resource allocation information is provided for each frequency, then precise resource control is achieved, but the signaling overhead and system complexity increase
Solution Approach 1:
The patent makes the resource allocation information universal by enabling it to be applied to multiple frequencies. The serving cell provides resource allocation information that can be used for sidelink discovery transmission on both the serving cell frequency and neighbor cell frequencies, eliminating the need for separate resource allocation signaling for each frequency and reducing overall signaling complexity.
Solution Approach 2:
The serving cell performs preliminary action by providing resource allocation information in advance before the radio terminal performs inter-frequency sidelink discovery transmission. This advance provision of resource allocation parameters allows the terminal to efficiently execute discovery transmissions on multiple frequencies without real-time coordination complexity.
3Area of stationary object
If the radio terminal monitors discovery signals only at the serving cell frequency, then the system operation remains simple, but the discovery coverage is limited to the serving cell area
Solution Approach 1:
The patent extends the discovery operation from a single frequency dimension to multiple frequency dimensions. By enabling inter-frequency sidelink discovery transmission and monitoring, the system expands the operational space from one frequency to multiple frequencies, thereby increasing discovery coverage area without proportionally increasing monitoring complexity through standardized frequency lists and resource allocation mechanisms.
Data Source
AI summary
A radio terminal according to an embodiment includes a controller configured to perform inter-frequency sidelink discovery transmission of transmitting a sidelink discovery signal at a frequency different from a frequency of a serving cell. The controller is further configured to receive, from the serving cell, a message including resource allocation information and frequency information. The resource allocation information is information indicating radio resources to be used for the inter-frequency sidelink discovery transmission. The frequency information is information indicating the different frequency to which the resource allocation information is applied.