An RF wirelessmodule is a module that uses wireless technology for wireless transmission. Itis widely used in computer wireless networks, wireless communications, wirelesscontrol and other fields. The wireless module is mainly composed of atransmitter, a receiver and a controller.
LoRa is one of the low-power WAN communication technologies. It is a superlong-distance wireless transmission technology based on spread spectrumtechnology adopted and promoted by Semtech. It is a unique modulation formatgenerated by Semtech's RF part. LoRa RF part The core chips are the SX1276 andSX1278. These chips are small in scale and high in efficiency, bringing highreception sensitivity to LoRa wireless modules.
The conventionaldigital data communication principle is to use as small a bandwidth as possiblethat is compatible with the data rate. This is because the number of bandwidthis limited and there are many users to share. The principle of spread spectrumcommunication is to use the maximum amount of bandwidth as much as possible,and the same energy is transmitted over a large bandwidth. Here, a smallportion of the spread spectrum bandwidth interferes with conventional wirelesssignals, but conventional wireless signals do not affect the spread spectrumsignal because the bandwidth is narrow compared to conventional signals. Forexample, the E46-TTL-1W module with the LORA spread spectrum transmissiontechnology of 170MHz has almost twice the transmission distance and penetrationcapability than the traditional FSK and GFSK modulation methods.
The E46-TTL-1Wmodule operates at 170MHz. The lower the frequency, the longer the wavelengthand the smaller the propagation loss. Therefore, it has strong penetratingdiffraction capability and is suitable for more complicated environments.Compared to the E32-TTL-1W module with a frequency of 433MHz, the signal lossis significantly lower after passing through the four walls.
Antenna gain is the ratio of the power density of the signal produced by theactual antenna at the same point in space as the ideal radiating element, underthe condition of equal input power. Antenna gain is not only one of the mostimportant parameters of the antenna, but also important for the operationquality of the wireless communication system. By increasing the antenna gain,the signal coverage in a certain direction can be increased, or the range isunchanged, but within the range. The signal strength is enhanced. Therefore, thehigher the antenna gain, the better, and the smaller the standing wave ratio,the better.
The FEC forwarderror correction code is a method to increase the reliability of datacommunication. In a one-way communication channel, once an error is found, itsreceiver will not have the right to request a transmission. FEC is a method oftransmitting redundant information using data. When an error occurs in thetransmission, the receiver is allowed to reconstruct the data.
The FEC error correction function on the software can greatly improve theanti-interference ability, and the coding efficiency is high, and the errorcorrection capability is strong. In the case of sudden interference, theinterfered data packet can be actively corrected, and the reliability and thetransmission distance are greatly improved; In the absence of FEC, such packetscan only be discarded. The module has data encryption and compressioncapabilities. The data transmitted by the module in the air is random, and thedata interception is meaningless through strict encryption and decryptionalgorithms. The data compression function has the probability of reducing thetransmission time, reducing the probability of interference, improvingreliability and transmission efficiency.
The air speed should be as low as possible, the higher the airspeed, the closerthe communication distance, and the higher the packet loss rate.