Narrowband transmission concept
In the communications industry, bandwidth generally has two meanings: one is the frequency bandwidth (bandwidth), and the other is the maximum transmission rate (bps). Narrowband transmission refers to the technology of limiting the signal to a relatively narrow frequency range for transmission during data transmission. Usually, the bandwidth of a narrowband signal is much smaller than the total bandwidth of the transmission channel, generally between a few kHz and tens of kHz, or even narrower.
The working principle is briefly introduced in the following four points:
(1) Signal modulation: Load the information of the baseband signal onto the high-frequency carrier, and carry the information of the baseband signal by changing the amplitude, frequency or phase of the carrier, such as amplitude modulation (AM), frequency modulation (FM), phase shift keying (PSK), etc.
(2) Channel coding: Process the original data at the transmitting end and add redundant code elements to improve the signal's anti-interference ability and error correction ability, such as parity supervision code, convolution code, Turbo code, etc.
(3) Synchronization technology: The receiving end needs to achieve carrier synchronization, bit synchronization and frame synchronization with the transmitting end in order to accurately receive and restore the signal.
(4) Multiple access technology: including frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), etc., which allow multiple users to share resources on the same narrowband channel and realize simultaneous communication between multiple users.
Advantages of narrowband transmission
Narrowband transmission is an emerging technology that can be widely used worldwide. It has unique advantages, such as wide coverage, multiple connections, strong anti-interference ability, stable data transmission, low rate, low cost, low power consumption, and architectural advantages.
Taking the E49 series narrowband module of Chengdu Yibite Electronic Technology Co., Ltd. as an example, the wireless module itself adopts narrowband transmission, which has the characteristics of concentrated power spectrum density, strong stability, strong anti-interference ability and long transmission distance. At the same time, the internal software uses the FEC forward error correction algorithm, which has the characteristics of strong error correction ability and high coding efficiency. The final performance is that in the case of sudden interference, the interfered data packets can be actively corrected, which greatly improves the reliability and transmission distance of communication. Compared with the spread spectrum transmission scheme, the standby current is smaller and the air transmission rate is high, which is its biggest advantage.
Under the same power condition, the narrowband transmission power density is greater than the ordinary communication power density, and the transmission distance is twice that of the ordinary module.
Application of narrowband transmission
Narrowband transmission technology has been widely used in many fields due to its low power consumption and strong penetration. The following are some of the main application fields.
Internet of Things In industrial production, narrowband transmission can be used to connect various industrial sensors, monitoring equipment and actuators to achieve real-time monitoring and automated control of the production process. For example, in industries such as petrochemicals and electricity, the sensor data distributed in different locations is transmitted to the control center through narrowband transmission modules, so that the staff can timely understand the equipment operation status and production environment parameters to ensure safe and efficient production.
Medical field Corporate offices need to process a large amount of data and network communication, so they have high requirements for network stability and speed. WiFi modules can effectively improve network quality and ensure smooth business.
Agricultural field In the production and circulation of agricultural products, narrowband transmission can be used in agricultural product traceability systems to achieve information tracking and recording of the entire process of agricultural products from planting, processing to sales. Consumers can obtain information such as the origin, fertilization and drug use, picking time, transportation process, etc. of agricultural products by scanning the product QR code to ensure food safety.
Transportation field Narrowband transmission can be used for traffic flow monitoring, intelligent parking management and road condition monitoring. For example, by installing traffic flow sensors on the road, data such as traffic flow and speed can be transmitted to the control center of the traffic management department through narrowband transmission, thus realizing intelligent control of traffic lights and real-time relief of traffic congestion.