Which Beacons are the Most Compatible?

We get asked a lot which beacons are the most compatible. All beacons, whether iBeacon or Eddystone, are compatible with iOS and Android. There are a few ‘tracker’ type Bluetooth devices around that don’t transmit the right Bluetooth header and can’t be seen on iOS but we don’t sell those.

Almost all beacons are slight derivations of a few standard circuit designs and firmware provided by Texas Instruments, Dialog and Nordic who produce the System On a Chip (SoC) inside beacons. Hence, they all transmit to Bluetooth standards.

Use of standard SoC Chip and firmware libraries ensures Bluetooth compatibility

The main area that can differ is the Antenna and PCB layout that can lead to different radiation patterns. The ability to detect a beacon isn’t affected and differences manifest themselves as differing beacon signal strength (hence range) and stability.

The main areas where beacons differ is not in compatibility but in physical characteristics such as battery size and waterproofing that are to be found as categories at the left hand side of our store.

One thing people don’t realise is that problems occur with phone compatibility rather than beacon compatibility. Over time, we have discovered about 5% of our customers have problems getting the Manufacturer’s configuration to app connect to beacons on Android. To be clear, this is only when apps need to connect (to change settings) as opposed to only scan for beacons so this doesn’t tend to be a problem (for end users) once everything is set up.

To answer the question, Bluetooth standards are such that all beacons can be seen on all phones and compatibility isn’t an issue. Problems we have seen have been related to phones rather than beacons. We have never had a beacon returned to us because it’s incompatible.

Bluetooth Standards Pros and Cons

Here at BeaconZone we create solutions based on products that use Bluetooth LE. The Bluetooth standards are created and maintained by the Bluetooth SIG. This post briefly explores the advantages and disadvantages of such standards and the opportunities and risks of going off-piste using 3rd party wireless standards.

The main advantage of the Bluetooth LE standard is interoperability. We can use beacons, sensor beacons, smartphones, gateways, single board computers such as the Raspberry Pi, laptops and desktops in solutions and be sure they can communicate using Bluetooth LE. More specifically, we can use the Bluetooth APIs on these platforms and they speak a common language and ‘just work’. Bluetooth has also recently introduced standards on top of the Bluetooth LE standard that provide for mesh networking and angle based location.

The Bluetooth LE standard has caused the ecosystem of System on a Chip (SoC) vendors such as Texas Instruments, Nordic Semiconductor and Dialog Semiconductor to create inexpensive sub-systems and SDKs that simplify implementing new products based on the standards. This, in turn, has created a large variety of devices that can talk to each other even though they use hardware from different vendors. The variety of devices has increased competition, keeping device prices down.

The problem with standards is that they evolve very slowly and might not be optimal for specific situations. This creates an opportunity for 3rd parties to create alternative wireless solutions such as Ultra Wideband (UWB) devices, custom mesh networking and custom location schemes that can provide better performance in aspects such as accuracy, physical range and battery life. These custom products cost more because they are more involved to create/manufacture and their unique features can command a higher price. However, there’s the risk that if/when the companies producing these products go out of business, your solution will become end-of-life with no second sourcing. This is a particular risk when the product involves some sort of software as a service (SAAS), irrespective of standards.

Choosing a wireless technology for your solution involves a trade off between performance, cost and risk. It’s wise to first seek a standards-based and stand-alone (not SAAS) approach and only deviate if you find what you need to do isn’t served by available solutions.

Android O Bluetooth 5 Device API Observations

Last March we took a closer look at Bluetooth 5 and concluded there are tradeoffs between long range, high speed, legacy (today’s) phone compatibility and efficient battery.

We are starting to see corresponding development APIs appear for devices that will detect Bluetooth 5 beacons. Android (O) has a new setPreferredPhy call that allows apps to choose the PHY modes mentioned in our previous article.

As expected, high speed and long range are mutually exclusive and if you want to remain compatible with older (current) beacons then you can’t have the high speed or long range. Long range and high speed are only supported if the hardware supports it which means old (current) smartphones won’t get Bluetooth 5 support through a software upgrade.

The availability of the Android API raises new questions. Our understanding is that PHY is a low level thing and that the Bluetooth hardware can only work in one PHY mode at a time. If so, what if an app changes the PHY? Does this switch for all apps? What are implications? For example, what if one app, for example an existing app, needs to use older beacons in compatibility mode while another app wants to use Bluetooth 5 long range beacons? Maybe we are wrong and the underlying Bluetooth 5 firmware somehow multi-tasks PHY modes? Finally, how does the app know the device is Bluetooth 5 capable? It remains to be seen how the fragmentation of capability and behaviour is going to be workable on a typical app. Will most apps end up defaulting to compatibility mode, the long range and high speed only being used for special cases (devices)? In any case, we can see it’s likely that Bluetooth 5 is going to complicate beacon app development.

28/6 UPDATE: In response to this post, Martin Woolley of the Bluetooth SIG answered all our questions! Hardware, hence Android O, can have several PHY modes active at the same time provided the underlying device supports this.

Bluetooth 5 Beacon Implementation Tradeoffs

We previously wrote about Bluetooth 5 and beacons. Now that more technical articles are available, we have been looking deeper into Bluetooth 5 and and how it might affect beacons, particularly in terms of compatibility and battery life.

Bluetooth 5 achieves a greater range without necessarily using more battery power. How? There’s an informative article by Martin Woolley that explains how range is more to do with how far the radio signal reaches and is still intelligible as opposed to how far the signal reaches. With current Bluetooth 4, the signal is actually going further than the working range but there’s noise in the signal such that the data can’t be reliably read. Bluetooth 5 (optionally) adds extra information to the data to allow error correction to be performed. This allows the data to be intelligible at a longer range. There are various PHY ‘modes’ that Bluetooth 5 can use with different capabilities:

LE 1M is what we have at the moment and will provide backward compatibility. The new LE Coded modes add error correction at the expense of a lower data rate. The LE 2M provides twice the data rate but actually less range than with Bluetooth 4. It can be seen that the ‘headline’ of Bluetooth x4 range and x2 speed are mutually exclusive. Bluetooth 5 is better than Bluetooth 4 but you can’t have everything. Bluetooth implementations will need to choose whether range, or speed is important. As beacons transmit very little data and speed of that data isn’t that important, we expect new beacons to use the coded PHY modes.

However, what about compatibility? If beacons need to remain backward compatible with current Bluetooth 4 phones then they will need to transmit LE 1M. There will be a tradeoff between long range needs and compatibility with today’s phones. Some beacons might do timeslicing between long range Coded and LE 1M advertising with a consequent significant degradation of battery life.

Another aspect that will affect battery use is that Bluetooth 5 allows a maximum transmit power +20dBm rather than +10dBm as at present. However, as now, higher output power will be under user (initial configuration) control.

In terms of using the new, larger Bluetooth advertising data size, this will need the iBeacon and Eddystone specifications to evolve. This is reliant on work by Apple and Google. Larger data sizes imply longer transmission time, about x2 to x8 the current transmission time. Most current beacons transmit for about 1ms (1 millisecond) every 100ms to 1000ms. New beacons will transmit between 2ms and 8ms again every 100ms to 1000ms. The transmission time has a direct, almost linear, affect on battery use.

[As an aside, if a beacon uses use LE 2M, without the longer range, then the transmission time will be cut by about a half. As most beacons are expected to support the longer range, in most cases there’s going to be a corresponding increase in battery use.]

It can be seen that for ‘Beacons 2.0’, compromises will have to be made. There are tradeoffs between long range, high speed, legacy (today’s) phone compatibility and efficient battery use that mean no beacon will have all these desirable attributes. There’s likely to be an even larger range of beacons and/or configuration parameters that tradeoff range, speed, compatibility and battery life. This is likely to complicate evaluation and rollouts.