Portable Device Roaming Between Access Points
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Solution Overview
Problem
Existing portable devices enrolled in IEEE 802.15.4 based WPANs are limited in roaming between multiple access point devices, leading to prolonged wait times for signal reception and poor user experience due to fixed channel operations and limited memory in access point devices.
Innovation Solution
A portable device can store network parameters of multiple access point devices in nonvolatile memory and use these parameters to roam between them by periodically scanning channels with extended preambles, allowing it to detect and connect to the correct access point device efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the portable device traverses multiple channels to find the enrolled access point device, then the portable device can locate the correct access point device, but the wait time is prolonged due to channel scanning delays
Solution Approach 1:
The portable device performs preliminary actions by storing network parameters (channel identifiers, network identifiers, encryption keys) of multiple access point devices in nonvolatile memory before actual connection is needed. This allows the device to skip the time-consuming channel traversal process and directly communicate with the enrolled access point device when user input is received.
2Quantity of substance
If multiple access point devices are deployed to support hundreds or thousands of sensor devices, then the system capacity increases, but the system complexity increases due to wired or wireless connections between access points and control panel
Solution Approach 1:
The control panel device is designed with universal functionality to communicate with multiple access point devices through a single data bus (either wired or wireless). This multi-functional capability allows the system to support hundreds or thousands of sensor devices across multiple access points without requiring separate control panels for each access point, thereby reducing overall system complexity.
Solution Approach 2:
The data bus serves as an intermediary communication channel between the control panel device and multiple access point devices. This intermediary structure simplifies the system architecture by providing a standardized communication interface, eliminating the need for complex point-to-point connections between each access point and control panel.
3Adaptability or versatility
If the portable device stores network parameters of multiple access point devices, then the portable device can roam between access points, but the memory requirements of the portable device increase
Solution Approach 1:
The network parameters stored in the portable device's nonvolatile memory are organized in a structured list format with specific local qualities - each entry contains only the essential parameters needed for connection (channel identifier, network identifier, encryption key) for a specific access point device. This localized, structured storage approach minimizes memory usage while enabling roaming capability.
Data Source
AI summary
Systems and methods of a portable device roaming between a plurality of access point devices with which the portable device is enrolled are provided. Some methods can include the portable device saving a respective network parameter of each of the plurality of access point devices, the portable device traversing a plurality of channels in which the plurality of access point devices operate, the portable device operating in a respective one of the plurality of channels to receive a packet from a respective one of the plurality of access point devices, the portable device comparing a received network identifier in the packet with the respective network parameter of each of the plurality of access point devices as saved, and responsive to a match, the portable device transmitting a command signal to the respective one of the plurality of access point devices.