How Do You Choose the Most Optimal Real-Time Location & Sensor Solutions (RTLSS) For Your Project?

How Do You Choose the Most Optimal Real-Time Location & Sensor Solutions (RTLSS) for your Project?
Illustration: © IoT For All

The real-time location market is expected to reach ~$40B by 2030 – almost 10X the market size today; stack the real-time sensor market on top, and the collective market value of Real-Time Location & Sensor Solutions (RTLSS) straddles $100B+ in value. The exponential growth of RTLSS is compounded by a variety of global macroeconomic trends, including:

  • Increased pressure on corporate ROI, thereby scaling the need for digitization, streamlined data, and analytics, especially in the aftermath of COVID-19. 
  • The proliferation of enabling technology – e.g., the introduction of lower-cost, hyper-accurate, and low-infrastructure hardware.
  • Workplace health & safety – enforcement of stricter employment policies.

Indoor RTLSS, in particular, is well-positioned to revolutionize industries such as supply chain, grocery logistics, and healthcare. Today, for example, hospital nurses spend an average of 1 hour per shift looking for misplaced equipment, resulting in millions of dollars lost per year to ‘wasted’ wages and equipment replacement. This, among many other use cases involving asset management, people tracking, and environmental sensoring have expedited adoption of real-time IoT technology across businesses big and small.

The quest to implement RTLSS, however, is riddled with confusion (to say the least). There are multiple radio protocols to consider, and it’s often difficult for business owners to assess which solution works best for each project. We’re here to help with this – for starters, we’ve created a set of 7 important considerations across the most common indoor RTLSS protocols today. Depending on which criteria matters the most for your project (e.g., cost vs. location accuracy, the hassle of set-up vs. scalability), we hope these comparisons provide you with directional guidance on how to choose the ‘optimal’ RTLSS.

Let’s get started!

The most common protocols used in indoor RTLSS today are BLE RSSI – fixed reader (mobile tags), BLE RSSI – fixed tags (mobile reader), BLE AoA, UWB, and Wireless Mesh.

Choosing RTLSS

To evaluate each of these protocols for your project, you may want to consider (at least) these 7 important criteria:

  1. Set-up cost, which generally increases when wiring/cabling or specialized staff training is required.
  2. Tag cost.
  3. Location accuracy.
  4. Battery-operated readers; these readers do not need wiring/cabling, thereby reducing infrastructure costs, staff training, and site intrusion.
  5. Susceptibility to environmental interference, including multi-paths, reflections, etc.
  6. Susceptibility to data flooding – i.e., network throughput; when too much radio traffic results in data packet collisions, jamming, and/or loss.
  7. Scaling operations to new sites.

At a high level, here’s how each RTLSS technology breaks down on the above-mentioned criteria.

Breakdown of each evaluation criteria by RTLSS technology

Let’s unpack each evaluation criteria a bit more to aid in choosing RTLSS that’s right for your project:

1. Set-Up Cost

Set-up cost
  • High: BLE AoA and UWB require wiring (e.g., through walls, under floors) to install expensive readers, which can cost up to 4 digits per unit and require specialized training & support.
  • Low-Medium: BLE RSSI (2) needs the mobile reader to have a continuous power source (e.g., using a smartphone as the reader) or transmit data through access points / gateways (e.g., Lora – requires purchasing expensive Lora gateways & specialized training).
  • Low: BLE RSSI (1) requires wiring, however, readers are generally cheap (<$100); Wireless Mesh leverages fully battery-operated tags & readers – install via a 2-sided sticker, straps, or screw. Minimal staff training & no site intrusion.

2. Tag Cost

Tag cost
  • Indexing BLE (RSSI & AoA) tags at 100 percent – UWB tags can cost 4-10X (400-1,000 percent), and Wireless Mesh can cost 1.3-1.5X (130-150 percent).

3. Location Accuracy

Location accuracy
  • BLE RSSI – fixed reader typically cannot discern beyond ‘room-level’ accuracy.
  • BLE RSSI – fixed tag and Wireless Mesh fulfill the vast majority of indoor project needs (locating wheelchairs, people, pallets, etc.).
  • BLE AoA and UWB accuracy is used for hyper-specific purposes (e.g., urgently locating a small surgery tool). Both need a direct line-of-sight (LOS) to objects in order to achieve sub-meter accuracy.

4. Battery-Operated Readers

Battery-operated readers
  • Wireless Mesh readers survive fully on battery (minimizing infrastructure and power-consumption costs).
  • BLE RSSI – fixed tag can be configured to 1) run on frequently-recharged battery (thus more power consumption costs), OR 2) leverage the likes of Lora as the data transmission protocol. Latter requires specialized readers (e.g., those that combine BLE + Lora protocols).

5. Susceptibility to Environmental Interference

Susceptibility to environmental interference
  • The large bandwidth of UWB allows for optimal immunity against signal interference (e.g., multipath, reflections).

6. Susceptibility to Data Flooding

Susceptibility to data flooding
  • BLE RSSI – fixed readers and BLE RSSI – fixed tags are limited to just 3 channels on the 2.4 GHz band; as a result, they’re susceptible to data flooding from other devices that operate on the same band/channels (e.g., WiFi, BLE on smartphones).
  • BLE RSSI – fixed reader also relies on mobile tags (which ‘shout’ signals to be picked up by the fixed readers); consequently, areas with a large density of tracked assets (e.g., hundreds of pallets within a ~900m2 space) will experience especially high flooding / lost packets.

7. Scaling Operations to New Sites

Scaling operations to new sites
  • To scale BLE AoA and UWB beyond a project zone (e.g., one part of a factory floor), professional work is needed to set up additional wiring for new readers.
  • BLE RSSI – fixed reader needs more wiring to scale, however, the process should be simpler (vs. AoA, UWB). 
  • To scale Wireless Mesh and BLE RSSI – fixed tag, simply put up more battery-operated devices, which can take just minutes per individual device.

With all these considerations in mind, here’s what a high-level decision tree might look like for your project:

RTLSS decision tree visual

To Conclude

Hope the above has been helpful! Remember though – there is no ‘one-size-fits-all’; each radio protocol will be ‘optimal’ in different scenarios, and sometimes even the same project may require multiple protocols (e.g., leveraging UWB to obtain sub-meter accuracy in certain project zones while leaning on Wireless Mesh for ease-of-deployment in others).

If you’re interested in exploring how to choose RTLSS – there is much more to unpack and considerations we didn’t have the opportunity to get into, such as the area of deployment layout, compatibility with existing infrastructure, etc. Keep an eye out for analyses on these topics in our future posts!

AetherIoT (pronounced ee·thr IoT) is a Real-Time Location & Sensor Solutions (RTLSS) aggregator – our hardware products span across multiple radio technologies (e.g., Wireless Mesh, UWB, GPS, among others). Our middleware platform provides nor...
AetherIoT (pronounced ee·thr IoT) is a Real-Time Location & Sensor Solutions (RTLSS) aggregator – our hardware products span across multiple radio technologies (e.g., Wireless Mesh, UWB, GPS, among others). Our middleware platform provides nor...