Questions regarding design choices for Wi-Fi modules in Shelly relays

[alverino]

I’m working on understanding design tradeoffs that appliance manufacturers make when selecting the Wi-Fi modules and functionalities for Wi-Fi-enabled household devices (e.g., Shelly relays). I would appreciate if you could answer some of the following questions, or connect me with someone who can. Thank you very much for your time and consideration!

 

Regarding the radio hardware:

1. What criteria is the most important for choosing between 2.4GHz or 5GHz frequency communications? Range? Throughput? Power consumption? Reliability? Robustness to interference? Chip costs/size?
2. What criteria is the most important for selecting between different Wi-Fi chipsets? Cost? Size? Form factor? Reliability? Power consumption? Ease of programming? Availability?

 

Regarding the Wi-Fi protocol:

1. What criteria is most important for selecting a Wi-Fi standard (i.e., 802.11a/b/g/n/ac/ax) to implement? Throughput? Reliability? Robustness to interference? Pre-existing codebase? Power consumption? Router compatibility?
2. The recent Wi-Fi 6 standard (i.e., 802.11ax) was designed with IoT applications in mind and is capable of handling significantly more connected devices without network congestion, compared to previous standards. Have y’all considered implementing Wi-Fi 6 on your devices? What are the main challenges, blockers, or non-starters to doing so?
3. The Wi-Fi Alliance offers certification programs to endorse the network functionality of Wi-Fi enabled devices. Have y’all considered certifying your devices through these programs? What are the main challenges, blockers, or non-starters to doing so?

 

Regarding local network reliability:

1. When setting up the device, what do you recommend testing for to ensure a reliable connection? Internet speed? Throughput? RSSI strength? What are the minimum recommended requirements for good network connectivity? Is a device able to notify the homeowner when these requirements are not met?
2. What happens when a device loses power or connectivity locally? Does it attempt to reconnect to the network? Is there a way to notify the homeowner if a device has been offline for an extended period of time?
3. Network connectivity issues due to network congestion in device-rich environments may be exacerbated by repeated reconnection attempts. How do your devices handle reconnection attempts and avoid flooding the network and causing more collisions? Is there a back-off algorithm or maximum number of retries implemented?
4. How often do devices accidentally disconnect from the network? Are they usually able to reconnect successfully or do they require human intervention? What are some of the more common issues that require human intervention to resolve?
5. If a device loses power and reboots, is it able to reconnect automatically to the network again? Or do passwords and configurations reset to factory defaults? If they reset, is this for security reasons or for simplicity of code or for some other reason?

 

Regarding household network reliability:

1. What happens when an entire building or household loses power or internet connectivity? Are there fall-backs in place to continue operation of the device?

 

Thank you for reading!

Edited July 29 by alverino
weird formatting

[Zyrkonim]

Quote

 

Designing Wi-Fi-enabled household appliances involves a number of considerations related to radio hardware, Wi-Fi protocols, and local network reliability. Here’s a detailed overview addressing each of your questions:

Radio Hardware Considerations

1. Frequency Choice: 2.4GHz vs. 5GHz

   • Range: 2.4GHz generally provides better range and penetrates walls more effectively than 5GHz, making it suitable for devices that need to operate across a larger area or through obstacles.
   • Throughput: 5GHz offers higher throughput and faster speeds due to less interference and wider bandwidth. It's preferred for applications requiring higher data rates.
   • Power Consumption: 2.4GHz radios typically consume less power than 5GHz radios, which can be a critical factor for battery-operated devices.
   • Reliability and Robustness: 2.4GHz is more susceptible to interference from other household devices (like microwaves and cordless phones), while 5GHz is less crowded but has shorter range and penetration.
   • Chip Costs/Size: 2.4GHz modules are usually cheaper and can be smaller, which can be beneficial for cost-sensitive or space-constrained applications.

2. Wi-Fi Chipset Selection

   • Cost: Budget constraints may influence the choice, especially for high-volume production.
   • Size/Form Factor: For compact devices, the size of the Wi-Fi module can be crucial.
   • Reliability: High-quality chipsets may offer better performance and fewer issues in the field.
   • Power Consumption: Critical for battery-powered devices, with lower consumption being preferable.
   • Ease of Programming: Some chipsets come with robust development tools and libraries, easing integration.
   • Availability: Supply chain issues can affect the choice; availability and lead times may influence the decision.

Wi-Fi Protocol Considerations

1. Selecting a Wi-Fi Standard

   • Throughput: Newer standards like 802.11ac and 802.11ax provide higher speeds and better performance.
   • Reliability: Newer standards often offer enhancements in reliability and error correction.
   • Robustness to Interference: 802.11ax is better at handling interference and congestion compared to older standards.
   • Pre-existing Codebase: Established standards often have mature libraries and tools available.
   • Power Consumption: 802.11ax is more power-efficient with features like Target Wake Time (TWT) designed for IoT devices.
   • Router Compatibility: Ensure compatibility with the most common routers used by consumers.

2. Implementing Wi-Fi 6 (802.11ax)

   • Challenges: Integration of Wi-Fi 6 can be complex due to its advanced features. Costs, development time, and ensuring compatibility with existing infrastructure are key considerations.
   • Blockers: Higher costs for advanced chipsets, increased development time, and the need for more sophisticated software might be barriers.

3. Wi-Fi Alliance Certification

   • Considerations: Certification ensures interoperability and adherence to standards.
   • Challenges: Certification can be costly and time-consuming. It involves rigorous testing and may require design adjustments.

Local Network Reliability

1. Testing for Reliable Connection

   • Internet Speed and Throughput: Ensure that the device performs well under expected network conditions.
   • RSSI Strength: Measures signal strength; should be sufficient for reliable operation.
   • Minimum Requirements: Typically, RSSI should be above -70 dBm for reliable connectivity. Devices often include diagnostics to alert homeowners of connectivity issues.

2. Handling Power Loss or Connectivity Issues

   • Reconnection Attempts: Devices should attempt to reconnect automatically. Many include mechanisms to handle intermittent connectivity gracefully.
   • Notification: Some devices can send notifications if they have been offline for a certain period.
   • Reconnection Strategies: Implementing exponential back-off algorithms helps to reduce network congestion during reconnection attempts.

3. Handling Disconnections

   • Frequency of Disconnections: Devices should reconnect automatically. Frequent disconnections may indicate configuration or network issues.
   • Human Intervention: Issues requiring manual intervention typically involve complex network problems or hardware faults.

4. Reconnection Post-Reboot

   • Automatic Reconnection: Devices generally reconnect automatically after a reboot.
   • Configuration Resets: For security reasons, some devices may reset configurations to factory defaults, but this is often avoided in favor of retaining settings.

Household Network Reliability

1. Power or Internet Outages

   • Fallback Mechanisms: Most IoT devices rely on continuous power and internet. In case of power outages, devices usually don’t operate until power is restored. Some may have basic functionality or limited local control features.

This overview should give you a solid foundation for understanding the trade-offs appliance manufacturers face in selecting Wi-Fi modules and functionalities. If you need more specific information or insights from industry professionals, I’d recommend reaching out to IoT hardware developers or consulting with industry experts specializing in Wi-Fi technology and appliance design.

 

 

So many topics and questions that I decided to answer you simple with the help of chatgpt, most of the answers are correctly and to the point.

[Heinz]

Hi @alverino

This was quite a lot of reading 😅. is this for IoT networks only or for networks overall? By the looks of it this looks like a research paper of some sort 

 

[alverino]

Hi @Zyrkonim, Thank you for the response! I think all the tradeoffs make sense. I suppose I was looking more for insight on specific decisions made for Shelly devices, and how they ended up falling on one side or the other of a decision boundary. For example, the Shelly 1 UL Smart Relay Switch only uses 2.4GHz Wi-Fi, has protocols 802.11 b/g/n, and seems to be Wi-Fi CERTIFIED. Supporting several Wi-Fi protocols and getting Wi-Fi certification require a non-negligible amount of time and money -- was there a clear market incentive to do so? Are there any plans on adding Wi-Fi 6 (802.11ax) to the list of supported protocols in a 2.4GHz-only capacity as well?

@Heinz Haha yeah, the inquiry is for a project I'm working on at LBNL. I guess I'm not really looking for anything general to IoT or networking overall, since the tech is all out there and the tradeoff spaces are pretty clear. I'm more curious about when companies get down to the nitty gritty of having to make decisions for consumer products with actual money and market effects on the line, what comes out when the dust settles and what were the main deciding factors that went into the design and implementation.

[Heinz]

@alverino

I will need to look into this as its alot of questions 😄 I can take some time on the weekend to awnser these questions 

 

[alverino]

@Heinz Thank you! I really appreciate that 😁