Ten Important Differences Between Bluetooth BREDR And Bluetooth Smart
As you may know, there are two major Bluetooth® technologies within the Bluetooth core specification, Bluetooth BR/EDR—Bluetooth Basic Rate/Enhanced Data Rate—and Bluetooth Smart technology. You can find them in the Bluetooth Core Specification, version 4.2, volume 2 and volume 6. As a Bluetooth developer, it is important that you understand the differences of each technology beyond the radio controllers and power consumption.
All radio communication takes place over some form of defined channel(s) for the band that that particular radio lives in. Bluetooth in no exception, but Bluetooth Smart actually uses its channels a bit differently than previous versions of Bluetooth, especially with the advent of advertising in Smart.
BR/EDR: 79 channels, channel index from 0 ~ 78, covering from 2400 ~ 2483.5MHz. Bluetooth Smart: 40 channels, channel index from 0 ~ 39 covering from 2400 ~ 2483.5MHz, index 37, 38 and 39 are advertising channels.
There are three Bluetooth logos to help differentiate between the types of Bluetooth used in a product. Manufacturers use these on product packaging or directly on the product:
You understand BR/EDR and Bluetooth Smart but you may not understand Bluetooth Smart Ready. If something is Bluetooth Smart Ready, it means it can receive data from other Bluetooth devices potentially to feed it into applications that turn that data into useful information (think smartphones, PC and tablets).
This is what makes Bluetooth Smart so special. Customers can use a coin cell battery to power up a Bluetooth Smart device for several months or even years. The flexible configuration of Bluetooth Smart allows the application to manage the connection intervals to optimize the working period of a transceiver. As for Bluetooth BR/EDR, because of its higher data throughput its power consumption can be higher. If you are interested in more information on this specific topic, please refer to Bluetooth V4.2 Core Spec, Volume 6, Part B, and Section 4.5.
BR/EDR supports Piconet, which has a star network topology. Likewise, Bluetooth BR/EDR supports Scatternet, where each Piconet has a single master and slaves participate in different Piconets on a time-division multiplex basis.
Bluetooth Smart version 4.1 supports “dual mode,” which allows a Bluetooth Smart device to have two roles at same time, Central and Peripheral. A device that supports the Central role initiates the establishment of a physical connection; any device that accepts the establishment of a low energy physical link using any of the connection establishment procedures would be in the Peripheral role. In the future, it will support smart mesh—the Bluetooth SIG Smart Mesh Working Group is currently working to provide a prototype for testing. Many applications like the smart home and industry automation will benefit from Bluetooth Smart Mesh technology.
Bluetooth Smart development is very flexible, with more flexibility for developers to customize their applications. Developers can utilize Bluetooth SIG adopted profiles or customize their own. No matter what kind of application scenarios you have in mind, the flexible profile definition can meet the technical requirements. In contrast, BR/EDR is a mature technology; the development is module level, so most of the development is directed towards integrating these modules into the product. For example, if you are developing a beacon application, you should choose Bluetooth Smart as BR/EDR would not support it.
Pairing is mandatory in Bluetooth BR/EDR but optional in Bluetooth Smart—if your application is very simple, you may not need pairing any more.
Bluetooth Smart has a throughput of about one Mbps (according to the specification), but this is dependent on the application scenario. The throughput of Bluetooth BR/EDR is more than two Mbps, and is suitable for high-quality audio bit streams or other higher bandwidth applications where you want to have a connected state.
One of the questions we often get is around some Bluetooth headsets claiming compatibility with Bluetooth 4.x, so does that mean the headset is low energy? Can I use Bluetooth Smart as an audio application? Let me explain.
Bluetooth 4.x core spec includes a low energy controller volume, but Bluetooth BR/EDR controller volume is also still in the 4.x core specification. Many times, if a headset claims to support 4.x, it is compatible with the 4.x BR/EDR spec, not the low energy spec, or Smart. You will need to check whether the product you bought is Bluetooth Smart by checking the Bluetooth Smart brand on the package.
The GATT (Generic Attribute) profile is designed to be used by an application or another profile, so a client can communicate with a server. Currently, there are many profile definitions built using GATT.
The BR/EDR profiles that do not have a corresponding Bluetooth Smart profile include headset (HSP), object exchange (OBEX), audio distribution (A2DP), video distribution (VDP) and file transfer (FTP). In the future, hopefully most (if not all) Bluetooth BR/EDR profiles will be migrated to Bluetooth Smart.
The Bluetooth SIG has three approaches to making Bluetooth Smart Internet compatible: RESTFul API, HTTP Proxy Service (HPS) and Internet Protocol Support Profile (IPSP). Each approach needs a gateway device as an interpreter. The gateway device could be a router, a set-top-box or an unused smartphone, essentially anything with access to the Internet. Internet capability for Bluetooth Smart is what makes the Internet of Things more reliable and achievable. Recently, Google announce their OnHub router, which connects Bluetooth devices to the Internet. You can find more details here https://on.google.com/hub/
I hope this helped you understand the most important differences among the different Bluetooth technologies and lead you to choose the right one for your own applications.