Patent ID: 8358587

Claim:
A system for performing a local wireless communication using a predetermined frequency band, the system employing frequency-variable signal detection, wherein at least a part of the predetermined frequency band is divided into a plurality of channels, the system comprising: at least a hub scanning each channel to identify available one of the plurality of channels, modulating data, and transmitting the modulated data over the available channel; and a plurality of sensors communicating with the hub, each sensor being set to start to operate when each sensor detects a signal in said predetermined frequency band, spectrum-sensing the signal of the frequency band for each channel, analyzing a header of packet data for each channel, and receiving and processing the packet data if the signal is identified to have a designated code, each sensor including a band detector, a processor, and a frequency-variable detecting unit, wherein: the band detector detects in real time a frequency band of a signal received from the hub, and only when the frequency band of the received signal is detected by the band detector to be within said predetermined frequency band, the band detector outputs the received signal to the baseband processing unit and the processor, upon receipt of the signal outputted from the band detector, starts to operate, transmits a control signal to the frequency-variable detecting unit, analyzes a header of packet data for each channel, and receives and processes the packet data if the signal is identified to have a designated code.