Concurrent Mode: Getting More Done with One Radio!

Most IoT devices in the market operate primarily in Wi-Fi station mode wherein they are associated to an Access Point (AP) and communicate to some kind of cloud. These devices sometimes also operate in Limited AP mode in certain cases such as during provisioning so that the smartphones/tablets can provide them with network credentials for the user’s AP.

GainSpan’s latest firmware release (ver. 5.2.1 GA and higher)  enables our modules to operate both as a Wi-Fi station and a Limited AP in a time-multiplexed manner giving the user the perception of concurrent Wi-Fi station and Limited AP mode operation. This patented networking mode is made possible by the dual core architecture of the GS2000 SoC along with the larger memory resources.

Applications for Concurrent mode include concurrent mode provisioning, uninterrupted field diagnostics and creating Personal Area Networks (PAN). Let’s examine these in detail below.

Verified Concurrent Mode Provisioning:

The most common provisioning technique used by IoT devices today is to come up in Limited AP mode and have the user enter their network credentials via a mobile App on a smartphone / tablet. Upon receiving the network credentials, the Wi-Fi radio in these IoT devices changes network modes from Limited AP to Wi-Fi station for the intended AP. This provides an easy Graphical User interface (GUI) for users to input their network credentials using their smartphone.

However, one major limitation of this method is that it does not confirm success. Provisioning could have failed for a number of reasons such as the user inputting incorrect network credentials, typos while entering credentials on a  smartphone/tablet (thanks, Autocorrect!), or the home AP being switched off.

GainSpan’s patented concurrent mode provisioning solves this problem. Here is how it works:

Blog-ConcurrentMode-Picture2
Fig 1: Concurrent Mode Provisioning
  • When invoked (typically by a push button), the GS2000 module starts the first networking interface in Limited AP mode. This could come up with WPA2-PSK security with a default per-device passphrase printed on the IoT device’s sticker (GainSpan recommends using WPA2-PSK security to avoid security holes in the provisioning process) or it could come up with Open security mode (i.e.,  no security)
  • The smartphone/tablet associates to this Limited AP mode network. Using an App on the smartphone/tablet, the user enters their home network’s credentials
  • Upon submitting these credentials, the GS2000 module launches the second networking interface and tries to associate to the home AP using the credentials just provided, while still maintaining the link to the smartphone / tablet
  • Once associated to the home AP, the GS2000 module does a ping verification test to the home AP to verify the association
  • This success (or failure) feedback is provided to users over the Limited AP interface from the GS2000 module to their smartphone/tablet

Typically, OEMs incorporate a BLE module in their design to provide this Limited AP-like link to the smartphone/tablet so that they can provide feedback to the user over BLE. This adds cost to the BOM and is an expensive solution given that the device will typically be provisioned only once during its life cycle.

GainSpan’s concurrent mode provisioning eliminates the need for a BLE chip and provides an easy, secure provisioning experience to the user.

Uninterrupted Field Diagnostics

To understand this use case, let’s consider a cloud-connected vending machine. This machine sends a lot of information to the cloud in terms of usage, stock levels, performance, logs, etc. This data is used by various parties such as store owner, maintenance technicians, stocking analysts and manufacturer to track its progress and help them take necessary actions as needed.

Blog-ConcurrentMode-Picture1
Fig 2: Uninterrupted Field Diagnostics

Uninterrupted Field Diagnostics

Consider a scenario where the vending machine sends an error code that prompts the owner to dispatch a service technician to the site for further diagnostics. The technician arrives and initiates the concurrent mode to establish a local Limited AP link between the vending machine and the tablet running the diagnostic software, while the vending machine still maintains cloud connectivity.

Diagnosing the product in the field without having to take it offline could be of profound importance to all parties involved in this use case. GainSpan’s concurrent mode makes this possible by providing two concurrent networking interfaces – namely a station interface for cloud connectivity and a Limited AP interface for a technician’s smartphone / tablet.

Creating a Personal Area Network (PAN):

Let’s consider a smart thermostat with a couple of battery- operated temperature sensors that can be placed in different rooms to better control the heating and cooling.

The thermostat unit being line powered operates in GainSpan’s concurrent mode and sets up two networking interfaces – the station interface to connect to the home AP for cloud connectivity and the Limited AP interface where the temperature sensors report the readings from different rooms.

Blog-ConcurrentMode-Picture3
Fig 3: Creating Personal Area Network (PAN)
  • Reduced BOM cost by eliminating the need for multiple radios to create a gateway in the thermostat unit
  • Eliminates the need for regulatory approvals on account of multiple radios in the system. Customers can leverage GainSpan’s modular approval certifications
  • Faster time to market as it is much easier to integrate one radio versus multiple radios into the system

GainSpan’s patented concurrent mode creates a new networking mode for IoT devices where they can act as a station and as Limited AP on two separate networking interfaces concurrently. When using GainSpan modules at both ends, concurrent mode enables battery-powered devices such as sensors to sleep longer and to maintain network connectivity without having to wake up periodically unless there is meaningful data to transmit. The Limited AP mode interface in concurrent mode supports up to 16 client devices with WPA2-PSK encryption. This unparalleled number of client device support gives OEM designers and embedded engineers the flexibility to architect their IoT device to meet all their technical needs while providing an easy development experience and designing a solution that is most cost effective.

How will you use GainSpan’s patented concurrent mode for your next IoT product? We’d love to hear from you.