摘要:
An ASIC for monitoring wideband GHz spectrum to sense respective frequency components present in the spectrum. The ASIC implements Fast Fourier Transform (FFT) techniques to facilitate identification of one or more frequency components of a sparse signal after the signal is sub-sampled at a rate below the Nyquist criterion. The ASIC computes a first Fast Fourier Transform (FFT) of a first sub-sampled set of samples of a time-varying signal representing the monitored spectrum and sampled at a first sampling rate, and further computes a second FFT of a second sub-sampled set of samples of the time-varying signal sampled at a second sampling rate different from the first sampling rate. In one example, each of the first FFT and the second FFT is a low-radix FFT to facilitate a low-power and low-cost ASIC implementation of wideband spectrum sensing.
摘要:
An ASIC for monitoring wideband GHz spectrum to sense respective frequency components present in the spectrum. The ASIC implements Fast Fourier Transform (FFT) techniques to facilitate identification of one or more frequency components of a sparse signal after the signal is sub-sampled at a rate below the Nyquist criterion. The ASIC computes a first Fast Fourier Transform (FFT) of a first sub-sampled set of samples of a time-varying signal representing the monitored spectrum and sampled at a first sampling rate, and further computes a second FFT of a second sub-sampled set of samples of the time-varying signal sampled at a second sampling rate different from the first sampling rate. In one example, each of the first FFT and the second FFT is a low-radix FFT to facilitate a low-power and low-cost ASIC implementation of wideband spectrum sensing.
摘要:
Methods and apparatus for monitoring wideband GHz spectrum for wireless communication, and sensing and decoding respective frequency components of a time-varying signal corresponding to the monitored spectrum. Concepts relating to sparse Fast Fourier Transform (sFFT) techniques facilitate identification of one or more frequency components of a sparsely occupied spectrum by sub-sampling the signal corresponding to the monitored spectrum at a sampling rate below the Nyquist criterion. The disclosed methods and apparatus may be implemented using conventional relatively low-power wireless receivers and using off-the-shelf relatively inexpensive low-speed and low-power analog-to-digital converters (ADCs) typically employed in WiFi devices or cellular phones, in tandem with unique processing techniques based on sFFTs and sub-Nyquist criterion sampling, and have demonstrated efficacy even in scenarios where the monitored spectrum is not sparse.
摘要:
Methods and apparatus for monitoring wideband GHz spectrum for wireless communication, and sensing and decoding respective frequency components of a time-varying signal corresponding to the monitored spectrum. Concepts relating to sparse Fast Fourier Transform (sFFT) techniques facilitate identification of one or more frequency components of a sparsely occupied spectrum by sub-sampling the signal corresponding to the monitored spectrum at a sampling rate below the Nyquist criterion. The disclosed methods and apparatus may be implemented using conventional relatively low-power wireless receivers and using off-the-shelf relatively inexpensive low-speed and low-power analog-to-digital converters (ADCs) typically employed in WiFi devices or cellular phones, in tandem with unique processing techniques based on sFFTs and sub-Nyquist criterion sampling, and have demonstrated efficacy even in scenarios where the monitored spectrum is not sparse.
摘要:
The wireless channel of the wireless communication system is selectively disrupted or interfered with based on the logical states of the data to be transmitted by an electronic device having no wireless data signal transmitting circuitry. A host device transmits a query packet which includes a header and a series of sub-frames to be received by a receiving device. As each sub-frame is transmitted, the electronic device can selectively disrupt the wireless channel by changing its characteristics such that the receiving device can no longer decode that sub-frame based on channel estimation from the header of the frame. Wireless channel disruption occurs in response to a specific state of the bit of data of a message to be communicated by the electronic device. The receiving device then issues a status reply to the host device indicating which sub-frames are decodable and which sub-frames are undecodable based on the initial channel estimation. The host device decodes the status reply to extract the message.
摘要:
A commodity RFID system is used for automatically measuring levels of soil moisture in planting containers. A large number of planting containers are used to grow pots in soil in a greenhouse. An RFID reader interrogates passive RFID tags affixed to the planting containers. The RFID reader can be attached to a robotic arm configured to move above multiple rows and columns of containers. Signal features (e.g., MRT, RSS, DMRT) of specific passive RFID tags affixed to specific ones of the containers are automatically monitored, based on the wireless interrogation of the specific tags by the reader. Soil moisture levels of specific containers are then automatically determined based on the signal features of the attached RFID tags, and effects of soilure moisture on electromagnetic fields of antennas of passive RFID tags.
摘要:
A novel method and system is disclosed for using a commodity RFID system for automatically measuring levels of soil moisture in planting containers. A large number of planting containers are used to grow pots in soil in a greenhouse. An RFID reader interrogates passive RFID tags affixed to the planting containers. The RFID reader can be attached to a robotic arm configured to move above multiple rows and columns of containers. Signal features of specific passive RFID tags affixed to specific ones of the containers are automatically monitored, including a minimum response threshold of RFID reader transmission power to activate the passive RFID tag (“MRT”), based on the wireless interrogation of specific tags by the reader. Soil moisture levels of specific containers are then automatically determined based on the signal features of the attached tags, and effects of soilure moisture on electromagnetic fields of antennas of tags.