Virtual Access Point Channel Management in IoT Networks

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Solution Overview

Problem

Deterministic routing in IoT networks, particularly in hub-and-spoke models using CSMA/CA, faces issues such as overwhelming servers with multiple traffic copies, excessive delay, and unacceptable frame loss, which are exacerbated in low-power lossy networks.

Innovation Solution

A supervisory device forms a virtual access point (VAP) by mapping multiple access points to a single logical entity, allowing nodes to communicate without roaming and optimizing channel usage through a communication schedule that instructs nodes to stop transmitting temporarily, thereby reducing latency and frame loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple access points transmit packets to a node using CSMA/CA, then the node can receive packets from multiple sources, but the server becomes overwhelmed with multiple copies of traffic

Engineering Contradiction:

Improvepacket reception capabilityVSAvoidtraffic copies

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The system segments traffic handling by introducing a supervisory device that divides and manages packet distribution. Instead of all APs transmitting to all nodes, the supervisory device segments the network into controlled transmission paths, assigning specific APs to transmit to specific nodes based on packet destination, thereby eliminating redundant traffic copies while maintaining multi-AP reception capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A supervisory device is introduced as an intermediary between multiple APs and nodes. This mediator receives packets from APs, determines the intended destination node, and selectively forwards packets only to the appropriate node. This intermediary prevents the server from being overwhelmed by filtering out redundant packet copies before they reach the destination

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If nodes transmit continuously in CSMA/CA networks, then data flow is maintained, but latency increases and frame loss occurs

Engineering Contradiction:

Improvedata flow continuityVSAvoidtransmission latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The system implements periodic action through scheduled transmission time slots assigned by the supervisory device. Nodes transmit data in designated time windows rather than continuously, creating periodic transmission patterns. This approach maintains overall data flow productivity while reducing collisions and latency by ensuring nodes do not transmit simultaneously, thereby preventing frame loss

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The supervisory device maintains continuity of useful action by continuously monitoring network conditions and dynamically adjusting transmission schedules. While individual nodes transmit periodically, the supervisory device ensures continuous packet forwarding and route optimization, maintaining overall data flow continuity without the latency and collisions associated with uncoordinated continuous transmission

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If access points share radio chains across multiple VAPs, then resource utilization improves, but channel availability for individual VAPs decreases

Engineering Contradiction:

Improveradio chain utilizationVSAvoidchannel availability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The system applies dynamics by enabling radio chains to dynamically switch between different VAPs and channels based on real-time network conditions. The supervisory device continuously monitors channel utilization and traffic demands, dynamically reassigning radio chains to different VAPs as needed. This dynamic allocation maximizes resource utilization while ensuring each VAP has adequate channel availability when required

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10433191B2Channel management in a virtual access point (VAP)

Publication Date: 2019.10.01 CISCO TECHNOLOGY INC

AI summary

In one embodiment, a supervisory device in a network forms a first virtual access point (VAP) for a first node in the network. A plurality of access points (APs) in the network are mapped to the first VAP as part of a VAP mapping and the first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network. The supervisory device determines a communication schedule for the first node based on a radio chain of at least one of the APs in the VAP mapping for the first VAP being shared by the first VAP and a second VAP for a second node in the network. The supervisory device, according to the communication schedule for the first node, causes one or more of the APs in the VAP mapping for the first VAP to instruct the first node to stop transmitting for a period of time.