What is the basic concept of transmit binary data wirelessly or from radio?
Here are so far my knowledge about it.
Any digital data (image, sound, video) is represented by binary digit (bit).
Binary digit only have two possible state, it's zero only or one only.
To transmit binary data via radio (wireless), we should encode binary series to the wave form. In this case we can encode with manipulating amplitudo of wave (AM) or frequency of wave (FM), anyway I feel FM choice is better.
For encode binary state to the frequency, it depends on convention. Here is my convention, if bit to send is currently one, then the frequency is higher, otherwise lower. Therefore maybe I should set threshold value so the receiver know what is higher frequency and what is lower frequency to help receiver decode binary.
I expect I can simply send and receive data like how Universal Serial Asyncronous Receive Transmit (USART) work. But USART work with wire not wireless which using voltage to encode/decode binary instead of radio frequency.
Suppose I have USART with standard baudrate 9600, how do I convert logical voltage to the frequency? So basically if voltage higher, then frequency is higher, otherwise lower.
I also expect I can transmit with distance more than 10 Kilometer.
Another question, what tools and module that I should prepare for this project? Here are my hypothesa:
- Antenna for receiver
- Antenna for transmitter
Maybe this project is simply done by using loraWAN.
Edit: my purpose is forwarding data from/to internet. Because one of node is internet active while one of node is not coveraged by internet.