D2D Message Latency Reduction via FDM Resource Pools
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Solution Overview
Problem
Current wireless communication systems face latency issues in device-to-device (D2D) message transmission, particularly in vehicle-to-everything (V2X) services, which are critical for applications like pre-crash sensing warnings, where latency requirements exceed 20 ms, and existing frame structures cannot meet these stringent demands.
Innovation Solution
The proposed method involves allocating separate resource pools for V2V messages with different latency requirements, using frequency division multiplexing (FDM) between scheduling assignment (SA) and data resource pools to reduce latency, and specifying a fixed timing difference between the reception of a grant and the associated SA transmission, allowing for faster data transmission without waiting for the next SA pool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single resource pool is used for D2D message transmission, then the system structure is simple, but the latency requirement of 20 ms for V2X services cannot be met
Solution Approach 1:
The patent divides the resource pool into separate SA resource pools and data resource pools. This segmentation allows independent optimization of scheduling information transmission and data transmission, enabling the system to meet the 20 ms latency requirement by reducing waiting time for resource allocation while maintaining manageable system complexity through structured resource organization.
2Loss of time
If FDM is used between SA and data resource pools, then latency is reduced, but the system complexity increases
Solution Approach 1:
The patent introduces frequency division multiplexing (FDM) to allocate SA and data resources in the frequency domain rather than only in time. This dimensional change allows parallel transmission of scheduling information and data, significantly reducing latency by eliminating sequential waiting time while the structured frequency allocation maintains system manageability.
3Loss of time
If the timing between grant reception and SA transmission is flexible, then the system is adaptable, but the latency for urgent messages increases
Solution Approach 1:
The patent establishes a fixed timing relationship where the UE transmits SA at a predetermined time offset after receiving the grant. This preliminary action eliminates uncertainty and waiting time for SA transmission, ensuring that urgent messages can be transmitted within the 20 ms latency requirement while the fixed timing pattern maintains system adaptability through predictable resource allocation.
Data Source
AI summary
A method and apparatus are disclosed for latency reduction of device-to-device message in a wireless communication system. In one embodiment, the method includes the UE receiving a grant on a first interface wherein the grant indicates resource for transmitting scheduling information and resources for data transmission on a second interface. The method also includes the UE transmitting a first scheduling information on the second interface in a first specific timing interval and transmits a second scheduling information on the second interface in a second specific timing interval, wherein the timing difference between the second specific timing and the first specific timing is indicated by the grant, and wherein the first scheduling information indicates a first timing offset between the first scheduling information transmission and the data transmission, and the second scheduling information indicates a second timing offset between the second scheduling information transmission and the data transmission, and the first timing offset is different from the second timing offset.