Multicast Relay Device for WLAN Reliability and Air Interface Efficiency

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Solution Overview

Problem

Current WLAN protocols, such as 802.11n/802.11ac, face challenges in supporting multicast transmission due to low transmission rates and high packet loss, which affects large-scale applications like video streaming and increases air interface occupancy time, impacting other devices on the same channel.

Innovation Solution

A multicast method that receives multicast service data through a unicast transmission protocol and forwards it to a multicast group via a multicast transmission protocol, using MAC addresses to ensure efficient and reliable delivery, potentially through both WLAN and wired networks, with the option for cascaded relay devices to enhance service reach.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low physical layer rate is used to transmit multicast messages to ensure transmission reliability, then packet loss is reduced, but transmission rate decreases and air interface occupancy time increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidtransmission rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The solution segments the transmission path into two parts: unicast transmission from transmitter to relay device (high reliability) and multicast transmission from relay device to receivers (high efficiency). This segmentation allows each segment to use the most appropriate transmission mode for its specific requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The relay device acts as an intermediary that receives multicast messages via unicast and forwards them to multiple receivers. This intermediary enables the system to combine the reliability of unicast with the efficiency of multicast without directly transmitting at low rates over the air interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a low physical layer rate is used for multicast transmission, then transmission reliability is improved, but air interface occupancy time increases and other wireless devices are affected

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidair interface occupancy time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The transmission path is segmented so that the time-consuming reliable transmission occurs over wired connections rather than wireless air interface. The air interface is only used for brief control signaling, dramatically reducing occupancy time and interference to other devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The relay device serves as an intermediary that handles the time-consuming transmission tasks through wired connections, freeing the wireless air interface from prolonged occupancy and reducing interference to other wireless devices in the network.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multicast-to-unicast conversion is performed in the AP, then transmission reliability is improved, but air interface occupancy bandwidth increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidair interface occupancy bandwidth
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The relay device acts as an intermediary that performs the multicast-to-unicast conversion function, but does so through wired connections rather than wireless. This eliminates the bandwidth overhead of transmitting multiple unicast streams over the air interface while maintaining transmission reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3324587B1Multicast method, multicast relay device and system
Publication Date: 2021.09.29 ZTE CORP
  • EP3324587B1 patent drawingFigure 1~2
  • EP3324587B1 patent drawingFigure 3~4
  • EP3324587B1 patent drawingFigure 5

AI summary

Disclosed are a multicast method for a Wireless Local Area Network (WLAN), a multicast relay device, and a multicast system. The method includes: receiving multicast service data forwarded by an Access Point (AP) through a unicast transmission protocol; and forwarding the received multicast service data to a multicast group through a multicast transmission protocol.