Robots can operate autonomic, but in most cases it needs to communicate with a operator or other robots. There are several technologies available to use in your robot. RC control can be used in aerial robotics and maybe you can use blue tooth in indoor applications.
This list below will give you a list of techniques:
- Bluetooth
- I2C
- Infra Red
- RC
- Serial
- Wifi
- Wires
You can divide communications in two groups. Internal and external communication. Internal is used to send information between modules inside the robot or extra periphery. External is used to communicate with the outside world like operators and other robots.