WLAN Channel Time Reservation for Real-Time Packet Latency

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Solution Overview

Problem

Current wireless communication systems using CSMA/CA fail to distinguish between real-time and non-real-time packets, leading to significant latency issues in transmitting time-sensitive real-time application packets due to random channel access and collision avoidance mechanisms.

Innovation Solution

The technology allows stations to identify and separate real-time packets from non-real-time packets, reserving future channel time for real-time packets, enabling scheduled transmission and minimizing latency by using a dedicated channel access scheme that prioritizes real-time traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CSMA/CA random channel access is used for all packets, then overall network throughput is improved, but latency for real-time packets increases significantly

Engineering Contradiction:
Improveoverall network throughputVSAvoidlatency for real-time packets
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent segments channel access into two distinct mechanisms: random channel access for non-real-time packets and scheduled channel access for real-time packets. This segmentation allows each packet type to use the access method best suited to its requirements, resolving the contradiction between overall throughput and real-time latency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary channel time reservation for real-time packets before actual transmission. By scheduling future channel time in advance and allowing early channel occupation, the system prepares the channel for real-time traffic ahead of time, eliminating the need for random contention and reducing latency while preserving overall network efficiency.

Inventive Principle:
Principle #10Preliminary action

2Speed

If channel contention period is shortened to accelerate access, then channel access speed is improved, but packet collision probability increases

Engineering Contradiction:
Improvechannel access speedVSAvoidpacket collision probability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent allows stations to occupy the channel before the scheduled channel time for real-time packet transmission. This preliminary channel occupation eliminates the need for short contention periods and reduces collision probability by reserving the channel in advance for guaranteed low-latency transmission.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If channel contention period is lengthened to avoid collisions, then packet delivery success rate is improved, but latency for real-time packets increases

Engineering Contradiction:
Improvepacket delivery success rateVSAvoidlatency for real-time packets
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements future channel time reservation that allows stations to secure channel access in advance of actual transmission needs. This preliminary reservation ensures high delivery success rates for real-time packets without requiring long contention periods, as the channel is pre-allocated and ready for immediate transmission when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a dynamic channel access system where real-time packets use scheduled access with pre-reserved time slots while non-real-time packets continue using random access. This dynamic differentiation allows real-time packets to achieve both high delivery success rates and low latency simultaneously.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3970437B1Reserving future channel time on wireless local area network
Publication Date: 2024.10.02 SONY GROUP CORP
  • EP3970437B1 patent drawingFigure 1
  • EP3970437B1 patent drawingFigure 2~4
  • EP3970437B1 patent drawingFigure 5

AI summary

A wireless communication circuit configured for communicating over a wireless local area network (WLAN) in its reception area to communicate real-time application (RTA) packets as well as non-real time (non-RTA) packets while utilizing carrier sense multiple access/collision avoidance (CSMA / CA). An RTA scheduling table is utilized for tracking active RTA sessions and managing transmission times for RTA traffic. Scheduling of channel time based on the expected RTA packet arrival time, and rejecting other packet transmissions during the scheduled channel time for RTA packet.