Bluetooth Technology Detailed Explanation

With the arrival of the Internet information age, mobile portable intelligent products will make countless "intelligent enthusiasts" crazy once launched. From the initial MP3 listening, wearable devices have gradually developed to wireless Bluetooth headsets and VR devices.

And wearable equipment market rapid growth cannot leave the development of Bluetooth communication technology, with the popularity of Bluetooth 4.0 technology and the rise of mobile Internet, Bluetooth technology application from portable devices like mobile phones, tablet to the Internet of things development, medical and other fields, the application scheme based on Bluetooth technology have sprung up, has brought new opportunities for Internet market.

When talking about Bluetooth, we often hear words such as BLE, Beacon, iBeacon, Eddytstone, etc. What are the connections and differences between them? The following is a detailed explanation of the common vocabulary and application of Bluetooth technology.

I. Bluetooth common vocabulary explanation

BLE:?Bluetooth Low Energy, Bluetooth Low power technology.

Beacon:?A precise positioning technology based on Bluetooth 4.0 protocol.

iBeacon:?Apple in 2013 launched a set of compliance with the Beacon technology agreement specification, the need to comply with the data format stipulated by Apple.

Eddystone:?Google launched a cross-platform open source Beacon format Bluetooth protocol in 2015.

Bluetooth in our daily life often refers to BLE, Bluetooth low power technology, as the name indicates, the current Bluetooth technology consumes very low power, unlike the rumor that you need to turn off Bluetooth to save power when you do not use it, the power consumption of Bluetooth on the mobile phone for a long time can be negligible.

II. The origin and classification of BLE

BLE, or Bluetooth Low power technology, originated in 2006 with Nokia's Wibree technology, which is called "Bluetooth Little" and is similar to Bluetooth but uses a fraction of the battery power of Bluetooth. The technology was later integrated into Bluetooth and became part of the SIG's Bluetooth 4.0 specification released in 2010.

The protocol stack of BLE is shown in the following figure. BLE is a set of protocols that are different from traditional Bluetooth, and the corresponding devices are not backward compatible. As a result, BLE has three device types:

1.Bluetooth devices, called Bluetooth BR/EDR: devices that only support traditional Bluetooth, such as some older devices, such as old cell phones, etc. Classical Bluetooth uses SPP (Serial Port Profile) to transmit data. SPP defines the Bluetooth device requirements required to simulate serial cable connection between two peer devices using RFCOMM Settings.

2.Bluetooth Smart Ready devices, called Bluetooth 4.0 dual mode, support both traditional Bluetooth and LE mode devices. IOS, Android and other new mobile phones, laptops, tablets support. Because the dual-mode controller integrates both BR/EDR and LE controllers, it is able to support both Bluetooth protocols.

3.Bluetooth Smart device, called BLE single mode, adopts LE Controller and supports only devices in LE mode. Beacon devices only support low energy Protocols, so they can run for long periods on a button battery.

Both BLE (Bluetooth Low Power) and traditional Bluetooth use the same band (2.4GHz). However, the transmission rate of BLE is low. The transmission rate of BLE at the physical layer is 1Mbps, which is equivalent to 125KB per second. BLE is not suitable for transmitting large amounts of data, but is generally used for device discovery and simple communication.

Both BLE and traditional Bluetooth can cover a range of 100 meters, but BLE has a slightly wider range. Compared with traditional Bluetooth, the biggest advantage of BLE is power consumption. The power consumption of BLE is reduced by 90% compared with traditional Bluetooth. Meanwhile, the transmission distance is increased, the security and stability are improved, and the AES encryption and CRC authentication are supported, which ensures the communication security of connected devices.

III. The Characteristics of Beacon Technology

Beacon, as a positioning technology based on Bluetooth 4.0 protocol, has attracted more and more attention in the indoor positioning market. With the development of Internet of Things information and the continuous accumulation of demand for big data acquisition and processing, Beacon technology with low power consumption and low cost has become the focus of indoor positioning applications. With its characteristics, it promotes the rapid landing of indoor positioning system of Internet of Things.

1. No pairing.

In my impression, we need to match Bluetooth devices in daily use. For example, when we open Bluetooth wireless headphones to connect with mobile phones, we need to match them, and when we bind smart bracelets to mobile phones, we also need to match them. And Beacon without pairing, because it is the use of Bluetooth broadcast channel to transmit signals, mobile phones and other devices without the Beacon device to establish a connection can work properly.

2. The background receives information.

Information push based on Beacon location needs App support. However, when we use indoor positioning function to receive Beacon signal, we do not need to open the App. We only need to open the corresponding App when we need to display Beacon information push service.

3 Beacon does not have the traditional sense of data transmission function.

Beacon device base station only pushes the information needed for positioning in the form of broadcast data, using the Bluetooth unconnectable mode.

If the APP developed to support it is to operate, transmit data and communicate with the server to achieve customer customization and obtain specific data, other data communication methods, such as Wi-Fi and 4G, should be enabled.

In addition, the use of Beacon positioning, can not use the network, and here the network refers to the server, Beacon positioning algorithm can be realized locally, that is, the device itself to complete the positioning and not through the online server calculation, provided that the map data needs to be located in advance to initialize written to the local device.

IV. What is the difference between iBeacon and Eddystone based on Beacon technology?

1.iBeacon

iBeacon technology is Apple in 2013 WWDC, launched a precision micro positioning technology based on Bluetooth 4.0 (Bluetooth Smart), the underlying technology is the use of BLE (Bluetooth Low Energy), the positioning technology in iPhone 4S support.

When your handheld device, such as a smart phone, is near a Beacon base station, the smart phone can receive the Beacon signal, the signal reception range can reach 50 meters.

Apple incorporated the iBeacon-related interface into the CoreLocation.framework. Google in Android 4.3 and later versions support the function, developers to use iBeacon technology, as long as the iBeacon technology standards can be met, but can not modify the protocol format, there are certain limitations.

2.Eddystone

Eddystone is a cross-platform open source beacon format Bluetooth LE beacon launched by Google on July 15, 2015, which is mainly used to send various information push to people in public places.

Since Google regards it as an open source project, Google traditionally does not name those open source projects with Google's name. For example, the Android operating system does not use Google's name. The public does not need to know which company Eddystone is from, as long as the OEM that makes the beacon and the corresponding app developer know.

Compared to the limitations of Apple's iBeacon, Eddystone is open source and can be used not only on Android, but also on iOS via linked library files. Eddystone has the source code on GitHub. Full open source code is also the biggest selling point of Eddystone, Apple on iBeacon's use rights custody is very tight, before Radius Networks company tried to run Apple iBeacon on Android system, Apple seriously dealt with this matter and eventually shut down this service.

In order to meet customer's demand, KOTONLINK also develop Bluetooth 4G GPS goods tracker. It can connect to external

Bluetooth temp/humidity sensor. And send those sensor data back to server, customer can see all sensor dada on platform

dash board. Very easy for customer to do industry and warehouse management.

Below is KOTONLINK KT-GA01 Bluetooth 4G GPS tracker:

V. Beacon equipment how to use BLE？

Through the above content, we understand BLE, Beacon, iBeacon, Eddytstone is exactly what, so for Beacon equipment, how to achieve the function based on BLE technology?

First, let's take a look at the complete BLE connection process.

1. Parse the broadcast scan connection process of BLE

(1) Broadcasting, also known as Advertising.

Host (Central) If the slave device is to be attached, the slave device must broadcast for the host to attach. The Advertisement Packet is sent at an interval ranging from 20ms to 10.24 seconds. The interval is called the broadcast interval. The broadcast interval affects the time it takes to initiate a subsequent connection.

The host must receive broadcast packets before sending a Connection Request to initiate a Connection with the slave. The slave listens only for connection requests from the host for a period of time after sending a broadcast packet. A broadcast packet can carry 31 bytes of data. It usually contains the user name, device information, and reachable identifier. There are four types of broadcasting:

1) Connectable Undirected Event Type

2) Connectable Directed Event Type

3) Scannable Undirected Event Type

4) Non-connectable Undirected Event Type

When the host receives a broadcast packet, it sends a Scan Request for more broadcast data, provided that the Active Scanner has been configured. The slave machine then responds to the Scan request by sending a Scan Response, which can contain an additional 31 bytes of data.

Broadcast, scan request and response using three different 2.4G frequency segments to avoid WLAN interference.

(2) Scanning

Scanning is used by the host to listen for broadcast packets and send scan requests. Two timing parameters need to be noted: Scan Window (the length of time a Scan takes) and Scan Interval (the total time of a Scan, including the time when the Scan stops and the time when the Scan takes place). For each scan interval, the time for the host to scan is equal to the "scan window", meaning that if the "scan window" is equal to the "scan interval", it means that the host is scanning continuously. Therefore, the duty cycle of the host scan is the "scan window" time divided by the "scan gap" time multiplied by 100 percent.

(3) Initiating the connection (Initiating the loading)

When the host wants to enter a connection, it goes through the same process as when scanning broadcast packets. When the host receives a broadcast packet during Connection initiation, the host sends a Connection Request to the slave.

(4) Connection

The roles of the host and slave are defined based on the first data exchange in the connection. When a connection is made, the host requests data based on an "Interval" defined by the slave. This gap time is called the Connection interval. It is used for host connections, but the slave can send Connection Parameter Updata Requests to the host.

According to the Bluetooth Core Specification, this time gap must be between 7.5ms and 4S. If the slave does not respond to a packet from the host within a time-frame, this is called Connection supervision timeout and the Connection is considered lost. It is feasible to achieve more data throughput by transferring multiple packets per connection gap. Each packet can be sent up to 20 bytes. However, if the current power consumption needs to be controlled, the slave machine has no data to send, you can choose to ignore a certain number of gaps. The gaps that are ignored are called slave latency. In a single connection, the device will perform frequency hopping (HOP) across all channels in the frequency band.

2. The use of Beacon

Beacon equipment only uses the broadcast communication channel, so there is no subsequent BLE connection related steps, and it is in this way, Beacon for low power indoor accurate positioning application field. As a beacon literally means, a device sends packets of data at regular intervals, and the transmitted data can be accessed by a host device like a mobile phone.

For example, a small thermostat can open a service to get current temperature or humidity readings. It can be connected, and the thermostat and the operating device can communicate with each other. Beacon is not connected, operating equipment only received Beacon broadcast signal, operating equipment according to the received broadcast signal for the next action.

VI. iBeacon technology use introduction

Here is how to use iBeacon:

(1) Attributes of iBeacon

IBeacon is essentially a Location information, so Apple integrated the iBeacon function into Core Location, which uses three main attributes to identify an iBeacon: proximityUUID, Major and Minor.

1. ProximityUUID is a NSUUID that identifies the company. Each iBeacon used by a company or organization should have the same proximityUUID, also known as a UUID.

2. Major is used to identify a group of associated beacons. For example, in the scenario of a supermarket chain, each branch's beacon should have the same major, which is similar to grouping, in order to better manage a large number of beacon devices.

Minor is used to identify a particular beacon, which is the equivalent of numbering a group of beacons, for example in a supermarket chain, to identify different items on a particular shelf.

If these attributes are not specified, they will be ignored when the device matches. For example, specifying only the CLBeaconRegion of proximityUUID matches all beacons of a company.

(2) iBeacon frame format

The frame format of iBeacon broadcast packet is as follows. We can see that the frame format consists of broadcast length, type, company ID, iBeacon type, iBeacon length, UUID, Major, Minor, and transmit power.

The Company ID is called the Company ID. As the name implies, it is to show the Company logo. For example, the following Company applies for the 16bit UUID of Bluetooth SIG: Baidu (0xFDC2, 0xFDC3), Xiaomi (0xFDAB, 0xFDAA, 0xFE95), Alibaba (0xFE3C), Nordic (0xFE59, 0xFE58).

The Company ID carries strong identification information that reflects the comprehensive capabilities of the iBeacon data service provider, but many users and companies do not have this ID. In the actual application of Beacon marketing and promotion, such as marketing information push in shopping malls, it is very important to show their own ID information, and the restriction of this parameter has certain limitations on the use of marketing and promotion.

In addition, we can see that the entire iBeacon data format is a single, each piece of code has been strictly limited, developers or users can only use according to the format, can not modify or develop their own.

VII. Eddystone technology application introduction

The following mainly introduces how to use Eddystone:

(1) Attributes of Eddystone

In addition to being open source, Eddystone supports multiple frameworks. Previously, Apple's iBeacon and Google's The Physical Web supported only one framework.

Eddystone is compatible with a variety of frameworks, and you can see different beacon vendors selling beacons for different purposes. This means that both iOS and Android phones can receive Google's Eddystone Beacon signal. This is very good news for merchants who need to push store information, which means that all mobile phones can receive push messages, rather than being limited by iOS system like iBeacon.

Multiple frameworks of Eddystone include data in UID, URL, TLM, and EID formats.

The original intention of Eddystone UID is to be compatible with iBeacon UUID. In order to break the limitation of only iBeacon UUID, UID can be set freely by the merchant. The APP can choose to only accept messages from the UID. Merchant apps can also figure out which stores a user is in around the world and push relevant information, such as coupons and Wi-Fi connections.

Urls are obviously much more versatile and simpler than Uids, and there are browsers on any phone that can open urls. In this one-off transfer, the user doesn't want to download the app specifically to receive the push message, so the URL is definitely the best choice.

TLM, the remote telemetry framework, is useful for businesses that need to manage a large number of beacons. Since most beacons are battery-powered, they need to be replaced or recharged after a period of time. The telemetry data framework allows beacons to send information about their status and power levels to nearby workers so they can target maintenance and replacement.

EID is a security framework that is a beacon that allows only authorized users to read information. For example, in a company, there are beacons in the lobby that are broadcast to all customers and visitors. However, the company also has messages that are broadcast only to employees, and they obviously do not want these messages to be seen by customers and visitors.

(2) Eddystone frame format

Instead of using the manufacturer data field, Eddystone places the value 0xFEAA in the full 16-bit service UUID field and holds the Beacon information in the associated service data field. Full details can be found below:

Beacon equipment using Eddystone technology can be widely used in close range promotion of goods, such as customers shopping near supermarkets and restaurants. Get location information at airports, train stations, scenic spots, museums. Keep track of assets against loss. Navigate inside the mall.

Beacon application cases based on BLE technology have blossomed everywhere in the market, and all kinds of technical information about Beacon can be found online. Whether at home or abroad, the vigorous application demand of Beacon technology has attracted more and more manufacturers into research and development, there are quite mature Beacon system scheme on the market, Such as wisdom museum, wisdom warehouse, wisdom zoo, wisdom cold chain, wisdom store, wisdom store, wisdom stadium, wisdom nursing home, wisdom hospital, wisdom exhibition center and other Beacon application solutions.