D2D Scheduling Signal Transmission for Legacy Compatibility
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Solution Overview
Problem
In direct device-to-device communication, reducing latency through shorter transmit time intervals (TTIs) can lead to increased collisions with legacy user equipment that cannot interpret the signals, as the scheduling assignment signals used to indicate resource availability may not be interpretable by legacy user equipment, causing data collisions.
Innovation Solution
Separating the transmission of scheduling signals from data transmissions, allowing the scheduling signals to be transmitted during a longer time interval while data transmissions can occur during shorter intervals, enabling legacy user equipment to interpret the signals and reducing collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If shorter transmit time intervals (TTIs) are used to reduce latency, then data transmission latency is reduced, but collision with legacy user equipment increases because legacy UE cannot interpret the scheduling assignment signals
Solution Approach 1:
The patent segments the communication functions into two separate transmission components: scheduling assignment signals transmitted at legacy-compatible intervals for collision avoidance, and data transmissions transmitted at shorter intervals for low latency. This segmentation allows each component to operate with optimal parameters independent of the other, resolving the contradiction between latency reduction and collision avoidance.
Solution Approach 2:
The scheduling assignment signal acts as an intermediary that bridges legacy and non-legacy user equipment. It is transmitted at legacy-compatible intervals and formats, allowing legacy UE to interpret it for collision avoidance, while the actual data transmission uses shorter intervals for low latency. The intermediary decouples the constraints between legacy compatibility and latency optimization.
2Loss of time
If scheduling assignment signals are transmitted at shorter intervals to match data transmission, then latency is reduced, but legacy user equipment cannot interpret the signals causing increased collisions
Solution Approach 1:
The patent applies different transmission interval qualities to different signal types: scheduling assignment signals use legacy-compatible longer intervals for broad compatibility, while data transmissions use shorter intervals for performance. Each signal type has locally optimized parameters suited to its specific function and receiver requirements.
Solution Approach 2:
The system dynamically assigns different transmission intervals to different signal types based on their functional requirements. Scheduling assignment signals maintain fixed legacy-compatible intervals for compatibility, while data transmissions use shorter intervals for latency reduction. This dynamic parameter assignment resolves the contradiction between speed and compatibility.
3Speed
If data transmissions use shorter time intervals to reduce latency, then transmission speed improves, but resource fragmentation and half-duplex issues increase
Solution Approach 1:
The patent segments resource management into scheduling resource pools and data resource pools with different interval structures. Scheduling resources operate at legacy-compatible intervals for simplified management, while data resources operate at shorter intervals for high speed. This segmentation reduces the complexity of managing mixed-interval resources by providing clear separation.
Data Source
AI summary
The method includes determining a time interval during which at least one other user equipment is to transmit a data transmission; generating a scheduling signal indicative of the data transmission; and transmitting the scheduling signal during the determined time interval.