An enhanced frequency-agile radio for avoiding undesired signal energy, based on a prediction, by scanning an available radio spectrum, measuring a receiver output, identifying an occupied portion of the available spectrum, predicting a level of undesired signal energy in a future scan, and storing the prediction. Enhancements provided by the frequency-agile radio include lowered implementation complexity appropriate for very low cost receivers and transceivers, reduced size due to elimination of larger components allowing for physically small pocket pager applications, increased anti-jam performance appropriate for wide area networks, increased receiver sensitivity and frequency tracking desirable for voice applications, enhanced signal coding error tolerance allowing operation within congested portions of the radio band and additional signal verification means which allow correct data reception from thousands of concurrently operating, collision prone transmit-only devices such as power utility meters and long range security systems.
RELATED PATENTS
This patent issued from a continuation-in-part patent application of a patent application entitled, FREQUENCY AGILE RADIO, having Ser. No. 08/103,993, with filing date Aug. 10, 1993, now U.S. Pat. No. 5,377,222, which was a divisional patent application of a patent application entitled, FREQUENCY AGILE SPREAD RADIO, having Ser. No. 07/880,268, with filing date May 8, 1992, now U.S. Pat. No. 5,311,541, with issue date of May 10, 1994. The benefit of the earlier filing date of the parent patent application is claimed pursuant to 35 U.S.C. .sctn.120.
A radar apparatus provided with a transmitting unit, antenna unit and a receiver unit. The transmitting unit transmits pulses having a modulation for enabling pulse compression on reception. As an ECCM feature, the radar apparatus is further provided with a blanking circuit. The blanking circuit includes two filters, one filter being responsive to the first half of the transmitting pulse only and the other filter being responsive to the second half of the transmitting pulse only. Blanking occurs if both filters simultaneously produce an output.
Disclosed is a real-time pulse sorting apparatus of a preprocessor in a pulsed radiation detection system. The apparatus, responsive to digital signals generated by a system receiver, uses the instantaneous frequency as the address input to store discrete data groups in main memory. Each data group, comprising the digital data corresponding to a single analog-to-digital converter sample point, includes the RF signal amplitude, inter-channel phase difference, instantaneous frequency as well as a unique pulse number generated by the pulse sorting apparatus. The present invention further includes a TOA memory for storing the time-of-arrival of each pulse at an address given by the pulse number. The main memory, organized in the form of a frequency-based histogram, together with the TOA memory, linked to the main memory by means of the pulse number pointer, sorts and records RF signal data with minimal processor control and intervention.
In summary, the spread spectrum direct sequence communication system of the present invention has a plurality of transmitters for uni-directionally simultaneously transmitting, through a transmission medium to a single receiver, a plurality of data streams. Each transmitter transmits a single data stream. Each data stream comprises a plurality of direct sequence data packets. Each transmitter has a data collector, a data formatter, a transmission device, a transmission interface, and a power supply.
A multi-mode radio frequency network comprises a first type of computing device having a radio receiver/transmitter adapted for communication over a narrowband frequency range, and a second type of computing device having a radio receiver/transmitter adapted for communication over both the narrowband frequency range and a wideband frequency range. A network access controller is adapted for communication with both types of computing device over respective ones of the narrowband and wideband frequency ranges. The network access controller provides synchronization signals for coordinating the timing of communications over the narrowband and wideband frequency ranges. The second type of computing device may be adapted for either frequency-hopping or direct sequence spread spectrum communication signals over the wideband frequency range. The synchronization signals further comprise periodic beacon signals that define discrete time periods which further include a synchronous portion for communication of the narrowband signals and an asynchronous portion for communication of the wideband signal. The multi-mode radio frequency network may further include data storage/retrieval devices and data collection devices adapted for communication with the first and second types of computing device over the narrowband frequency range.
A radio LAN system based on a frequency hopping control scheme in which a deviation between frequency hopping timing in a cell and frequency hopping timing in another cell is measured, and as the deviation increases close to such a degree that causes interference, a frequency hopping pattern currently used in the cell is replaced with another frequency hopping pattern, or the order on the frequency hopping pattern is changed to avoid interference between the cells.
