CV2X Semi-Persistent Scheduling With Adaptive Message Periodicity
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Solution Overview
Problem
Existing decentralized congestion control (DCC) algorithms in cellular vehicle-to-everything (CV2X) communications suffer from poor performance due to misalignment between sidelink control information (SCI) reservations and actual device usage, leading to inefficient resource selection and increased latency in semi-persistent scheduling (SPS) in congested areas.
Innovation Solution
Adjusting the basic safety message generation periodicity based on SPS periodicity to align with SPS resource allocation, reducing latency and information age by aligning message generation times with transmission times, and utilizing hysteresis parameters to manage periodicity adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DCC algorithms are implemented with SCI reservations, then resource allocation is established, but resource selection becomes inefficient and latency increases in congested areas
Solution Approach 1:
The patent implements dynamic SPS resource reselection mechanisms that allow UEs to adaptively change their resource allocations based on real-time channel conditions and congestion levels. The network can trigger reselection events that dynamically update SPS configurations, transforming the static resource allocation into a dynamic system that responds to changing conditions, thereby reducing latency while maintaining allocation accuracy.
Solution Approach 2:
The patent employs feedback mechanisms where the network monitors SPS usage patterns and channel conditions, then provides feedback through downlink messages to adjust SPS configurations. This feedback loop enables the system to identify and correct inefficient resource selections, reducing latency by reallocating resources based on actual usage patterns and congestion feedback.
2Reliability
If SPS resources are reserved in congested areas, then resource allocation is established, but resource usage becomes inefficient due to full usage maps
Solution Approach 1:
The patent implements preliminary SPS resource reservations that are established in advance based on predicted usage patterns rather than waiting for actual demand. By pre-allocating resources before congestion fully develops, the system avoids the inefficiency of selecting from fully occupied usage maps, thereby improving both reservation accuracy and selection efficiency.
Solution Approach 2:
The patent enables UEs to autonomously perform SPS resource reselection based on local measurements of channel conditions and congestion levels. This self-service mechanism allows devices to independently identify and select efficient resources without waiting for network-directed reallocation, improving resource selection efficiency while maintaining accurate reservations.
3Loss of time
If message generation periodicity is adjusted to align with SPS periodicity, then latency is reduced, but system complexity increases due to periodicity coordination
Solution Approach 1:
The patent merges the message generation periodicity with the SPS periodicity by synchronizing their timing structures. Instead of treating them as separate periodicities that need complex coordination, the system combines them into a unified periodic structure where message generation naturally aligns with SPS transmission opportunities, reducing latency while simplifying the coordination mechanism.
Solution Approach 2:
The patent creates a universal periodicity framework that serves multiple functions simultaneously: it governs both SPS resource allocation and message generation timing. This multi-functional periodicity structure eliminates the need for separate coordination mechanisms, reducing system complexity while achieving the latency reduction benefits of aligned periodicities.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, techniques for improving semi-persistent scheduling performance, including in the context of cellular vehicle-to everything (CV2X) communications, are provided. For example, a method of wireless communication performed by a user equipment can include determining a first periodicity for transmitting safety messages, determining a second periodicity for transmitting the safety messages, wherein the second periodicity is different than the first periodicity, determining, based on a probabilistic determination process, whether to continue with the first periodicity or switch to the second periodicity, generating, based on the determination to continue with the first periodicity or switch to the second periodicity, the safety messages at the first periodicity or the second periodicity, and transmitting the safety messages at a same periodicity at which the safety messages were generated. Numerous other aspects are provided.