PTM Resource Allocation with Variable TTI Durations
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving low latency point to multipoint (PTM) communications, particularly in efficiently allocating and managing transmission time intervals (TTIs) to support high data rates and quality of service requirements for multiple users, leading to increased latency and reduced system performance.
Innovation Solution
A method where a base station allocates distinct sets of wireless resources with different TTI durations for PTM and unicast transmissions, allowing for dynamic or semi-static indication of TTI durations, and prioritizing PTM transmissions to reduce latency and enhance concurrent data delivery to multiple users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single TTI duration is used for all transmissions, then system complexity is reduced, but latency performance deteriorates for latency-sensitive traffic
Solution Approach 1:
The patent implements dynamic TTI duration selection where the base station can configure different TTI durations (first TTI duration for low latency, second TTI duration for normal operation) and switch between them based on traffic requirements. The network can dynamically indicate which TTI duration to use for specific transmissions, allowing the system to adapt TTI length to latency sensitivity without permanently increasing complexity.
Solution Approach 2:
The patent changes the TTI duration parameter based on traffic type and latency requirements. By configuring multiple TTI duration values and selecting appropriate ones for different transmissions, the system optimizes latency performance for sensitive traffic while maintaining normal operation for other traffic, resolving the contradiction between fixed complexity and variable performance requirements.
2Productivity
If separate resource allocation for PTM and unicast transmissions is implemented, then resource management efficiency improves, but signaling overhead increases
Solution Approach 1:
The patent uses a unified RNTI (Radio Network Temporary Identifier) for both PTM and unicast transmissions. This single identifier serves multiple functions: it identifies both types of transmissions and carries scheduling information for both. By making the RNTI universal, the system achieves separate resource management for different transmission types while avoiding the need for separate identifiers and reducing signaling overhead.
3Loss of time
If shorter TTI duration is used for PTM transmissions, then latency is reduced, but resource allocation complexity increases
Solution Approach 1:
The patent segments resource allocation by using different TTI durations for different transmission types. Shorter TTI duration is allocated specifically for low-latency PTM transmissions, while normal TTI duration is used for unicast and other transmissions. This segmentation allows the system to reduce latency for critical traffic without requiring complex resource allocation for all transmissions, as the shorter TTI is applied only where needed.
Data Source
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AI summary
Techniques for low latency point to multipoint (PTM) communications in a system supporting communications using multiple different transmission time interval (TTI) durations are provided. The low latency PTM communications may be supported by one or more physical channels that support PTM communications at shortened TTI durations. In some examples, a base station may allocate, in a PTM traffic channel, a first set of resources for PTM transmissions with a first user equipment (UE) and a second UE, and may allocate a second set of resources (e.g., in a physical downlink shared channel (PDSCH)) for unicast transmissions to the first UE. The PTM transmissions may be transmitted using TTIs configured with durations shorter than TTIs used for transmitting unicast transmissions. Different sets of PTM resources may be allocated for different PTM transmissions having different TTI durations.