Controlling groups of electrical loads via multicast and/or unicast messages
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Solution Overview
Problem
Existing lighting control systems face limitations in wireless communication, particularly with multicast messages, which can lead to interference and link saturation, resulting in undesirable choppiness or failure in controlling lighting levels due to rate limits, and unicast messages cause distracting individual control of lighting devices.
Innovation Solution
A load control system that dynamically determines whether to use multicast or unicast messages based on user interface events, with multicast reserved for drastic changes and unicast for incremental adjustments, and includes a hub device to manage message transmission and ensure efficient communication by calculating delays between unicast messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicast messages are used to control groups of lighting devices, then communication efficiency is improved, but network interference and link saturation occur causing rate limits and choppiness
Solution Approach 1:
The system dynamically switches between multicast and unicast message types based on the current communication state and requirements. The hub device monitors network conditions and selectively applies different message transmission modes to optimize both efficiency and reliability in different operational contexts.
Solution Approach 2:
The invention changes the message transmission parameter (from multicast to unicast or vice versa) based on detected user interface events and network conditions. This parameter change allows the system to adapt to different control scenarios, using multicast for efficiency when appropriate and unicast for reliability when needed.
2Reliability
If unicast messages are used to control each lighting device individually, then communication reliability is improved, but devices turn on/off or adjust intensity at different times causing distraction
Solution Approach 1:
The hub device dynamically adjusts the transmission timing of unicast messages based on the network propagation characteristics and device positions. By calculating appropriate delays between messages sent to different devices, the system ensures synchronized operation while maintaining the reliability benefits of individual addressable communication.
Solution Approach 2:
The system performs preliminary calculations of message transmission delays before actually sending unicast messages to individual devices. This preliminary action allows the hub to pre-determine the optimal timing sequence that will result in synchronized device responses, preventing the distracting out-of-sync operation.
3Ease of operation
If multicast messages are transmitted frequently to maintain smooth lighting control, then lighting control smoothness is improved, but communication rate limits are exceeded causing interruptions
Solution Approach 1:
The system changes the message type parameter from multicast to unicast when approaching rate limits, allowing continuous smooth control without exceeding network capacity. This parameter change enables the system to maintain control smoothness through alternative communication pathways when the primary multicast channel becomes constrained.
Solution Approach 2:
The invention uses unicast messages as a supplementary partial action when multicast rate limits are approached. Rather than completely switching modes, the system can use unicast for specific devices or specific control operations to supplement multicast communication, maintaining overall smooth control while staying within rate limits.
Data Source
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AI summary
A load control system (100) includes control devices for controlling electrical loads, such as a motorized window treatment (130) and lighting devices (112, 122). The control devices include load control devices, such as a lighting device (112, 122) for controlling an amount of power provided to a lighting load, and input devices, such as a remote control device (116) configured to transmit digital messages comprising lighting control instructions for controlling the lighting load via the lighting device. The remote control device (116) may communicate with the lighting device (112, 122) via an intermediary device, such as a hub device (180). The remote control device (116) detects a user interface event, such as a button press or a rotation of the remote control device. The remote control device (116) or the hub (180) device determines whether to transmit digital messages to as unicast messages or multicast messages based on the type of user interface event detected. The load control devices may also include a motorized window treatment (130). The input devices may also include a remote control device (150), an occupancy sensor (160), a daylight sensor (170), and a network device (190), such as a smart phone, which may include a visual display (192). The remote control device (116, 150) or the hub device (180) may transmit the digital message as a unicast message when the user interface event is determined to be an "on" event or an "off" event and the number of multicast messages transmitted within the predefined period of time is outside of a predefined threshold. The remote control device (116) may be a retrofit remote control device capable of covering a switch installed on the wall-mounted load control device (110). The remote control device (116, 150) or the hub device (180) may calculate a delay between the transmission of each unicast message. The delay may be injected between unicast messages to help ensure that the communication link is idle prior to the device sending the next unicast message.