Wireless Communication Technology and Coexistence Mode in Internet of Things
The beginning of wireless
When it comes to the history of smart home development, we have to mention ZigBee technology. The ZigBee is based on the IEEE 802.15.4 standard and uses the frequency band 800Mhz/900Mhz/2.4G. Because of its low cost and its unique skip-to-band transmission characteristics, it is industrially controlled and industrialized. Control equipment vendors are very popular.
Since it was introduced in 2001, it has been widely used in the field of object connection and wireless communication because of its low power consumption and long transmission distance. We can think that the birth of ZigBee technology is the bud of the Internet of Things, and ZigBee is used in the field of industrial control. At the beginning of this technology, it was widely used. People began to realize that the simple character wired connection can no longer meet our actual needs. We need more wireless connection of objects and personal interaction in the practical application scenario. We can Think this is the meta-era of the Internet of Things.
Wireless innovation
In 2013, Qualcomm launched the industry's first WIFI low-power SOC, completely breaking the people's awareness of the Internet of Things. WIFI is based on the 802.11 protocol and works in the 2.4G/5G band. Because of the characteristics of its wide area network access capability, people have an eye on IoT technology.
At the same time, based on our country's sound Internet technology development capabilities, people's awareness of the Internet and cloud concepts, smart terminals, we can more easily connect all things. I think this is the era of the Internet of Things 1.0. The significance of the WIFI connection is not only the change of the connection mode, but also the change of the mode of thinking. The connection becomes a physical communication method, and the Internet has become the spiritual support.
In the past two years, the Internet of Things has grown from a bud to an embarrassment. Now it is widely recognized that the WIFI connection of the Internet of Things has played a role in connecting the players and brings hope to equipment manufacturers. We are excited to welcome this change, but with manufacturers. There is a problem in the deep exploration of this direction that manufacturers have to face again, that is the power consumption problem of WIFI.
Wireless expansion
It is true that Qualcomm has optimized the power consumption of this SOC specifically for the Internet of Things market, but because of the WIFI's characteristics, power consumption does not have much advantage in traditional low-consumption technologies. Like Zigbee and Bluetooth, people are starting to revisit the ways and advantages and disadvantages of low-power physical connections.
About ZigBee has been introduced in the opening, on the Bluetooth, is actually a technology earlier than the birth of ZigBee, based on the IEEE 802.15.1 protocol, the transmission channel is 2.4-2.485GHz, Bluetooth was born out it is widely used in wireless communication technology, For example, Bluetooth headsets, Bluetooth printers, etc., with the development of smart wearable technology in the past two years, Bluetooth has been added a new vitality. Before the concept of the Internet of Things was widely accepted, Bluetooth has always been a good friend of WIFI. As a technology derivative of WIFI, Bluetooth has played a great role, for example, in the high-end standard models of our mobile notebooks or smart phones. Bluetooth and WIFI are always present in the device. In the past two years, the AI ​​audio has been widely introduced by the market, giving people a new way of interacting with the Internet of Things, and Bluetooth has been given new vitality.
Wireless convergence
In the front, we introduced ZigBee, WIFI, and Bluetooth technologies in the Internet of Things (IoT) applications. As IoT connectivity becomes more and more extensive, various areas of the Internet of Things are booming. For example, smart homes, smart wearables, and smart cars are developing in depth. There is an increasingly urgent need for the integration of these three technologies.
Although these three technologies are three kinds of communication methods of the Internet of Things, the applications used are not completely overlapped. ZigBee is widely used in sensors and other markets. WIFI is used in non-power-consumption and other home appliances and gateways, and Bluetooth. Applied in the fields of smart wear and AI audio, these three technologies have played a complementary role in the real world of IoT. Therefore, from the perspective of application scenarios, these three technologies are set off against each other, and then the issue of gateway vendors for IoT comes. Now that there is a necessity for existence and integration, then whether or not it can be achieved technically at the same time, the answer is: Yes, but there are challenges.
As already mentioned above, the three communication methods will work in one frequency band at the same time. We all know that wireless communication in the same frequency band will interfere with each other. This problem will actually exist. We have merged these three technologies and we have started. The processing method is the same. Whoever is strong and disorderly competes. We have no restrictions on the mechanisms of the three communication methods. Because there are technical retransmission mechanisms, Bluetooth and ZigBee data volume are small, so in some fields of application Above, we simply superimposed the concept of fusion, relying on the work characteristics of retransmitting a very small amount of data. There are no restrictions on the three technologies. Communication is achieved through competition. In actual design, we usually isolate and use PCB layouts. Antenna placement and other methods to do their best to avoid the impact of interference, Runxin technology also based on WIFI and Bluetooth coexistence and ZigBee expansion interface has done a lot of excellent QFN low power gateway module.
Wireless coexistence
With the increasing number of terminal devices, people need to connect more devices, more distant distances and higher throughput. At the same time, with the emergence of AI audio technology, people have increasingly high aesthetic values ​​for gateway devices. A threshold, which also forced equipment manufacturers to choose a more compact outside, so in the technically higher gain antenna, the smaller layout is becoming more and more trends, the hardware we have previously selected countermeasures have become more and more The bottleneck, so we are increasingly urgently required to change the working conditions of the disorderly competition in the mechanism, so that effective cooperation with alternative bad competition.
In fact, the coexistence of mechanisms is not a strange technology. In the above, we also introduced mobile phones and laptops. This technology has always existed, but it mainly exists in terminals, but in the Internet of Things market, we are more concerned about the integration of gateways. We have an urgent need to extend the terminal technology to our gateway. Thankfully, as the market is expected to develop, chip manufacturers and more drivers will gradually improve the technology in the gateway part. We only need hardware. Do some logic control, these three technologies can be effectively implemented in the gateway.
In the implementation of the hardware circuit, we set the priority of the three communications. If the WIFI communication has no priority or high BT/ZB priority, we will interrupt the WIFI work. We only need to use the GPIO port to represent each communication separately. Priority and communication status are used to indicate the status of WIFI, ZigBee and Bluetooth, and three communication methods are divided by time division. Runxin agent’s Qualcomm product line has already produced the relevant AP solutions based on these three coexistence rates. We have also synchronized with a number of customers to bring such solutions to the market. The following is the Quntong-based coexistence design solution DK07 launched by Runxin. The basic block diagram is as follows:
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