National Semiconductor Corporation

Cisco Systems Inc.

Netwave Technologies Limited

Peter K Cripps

Ian L Sayers

Paul Jan Long

Tomany Szilagyi

A communications system extending over a cellular region and formed of a plurality of wireless cells. The communications system extends over a cellular region formed of a plurality of wireless cells. Each cell covers an area which includes a portion of the cellular region. Each particular cell includes a base station having a transmitter for transmitting a particular cell signal having parameters including a transmitting frequency and a transmitting power. The particular cell signal is transmitted to cover a portion of the cell region. Each of the base stations includes a parameter detector for detecting the other parameters of the other cell signals from the other cells in the cellular region. A parameter controller controls the particular parameters for the particular cell. The parameters for the particular cell are based upon the other parameters for the other cell signals so that the particular cell signal does not interfere with the other cell signals in the cellular region.

Method and apparatus for controlling wireless networks

A communications system extends over a cellular region formed of a plurality of wireless cells where each cell covers a portion of the cellular region. Each cell has a base station clock unit that facilitates reliable and accurate synchronization with other clocks units in other cells using a master clock signal from a global positioning system (GPS) or other accurate frequency source. The clock unit in each cell includes a local clock providing a local clock signal for clocking the cell. A master clock source provides one or more master clock signals and a clock synchronizer receives the master clock signals and forms a synchronizing master clock signal for synchronizing the local clock signal. In one or more of the wireless cells of the communication system, the clock unit is a master clock unit which includes a clock distributor for distributing a distributed master clock signal to one or more other wireless cells having slave clock units.

Synchronizing clock signals in wireless networks

A wireless local area network includes a radio transmitter/receiver for transmitting and receiving in accordance with the FCC rules for the ISM band. The receiver/transmitter supports spread spectrum frequency hopping in the 2.4 GHz ISM band and can be tuned to one of e.g. 82 different frequencies spaced at 1 MHz intervals. The radio transmitter/receiver is a low cost, low power, small size unit located on a printed circuit board in a PCMCIA form factor. Third order mixers are used in combination with a switched prescaler for a low cost and compact frequency control system capable of rapid switching of the radio between transmitting and receiving functions. No special shielding is needed between the frequency control circuitry and the receiver IF circuitry.

Radio transmitter/receiver for wireless local area network

A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ('FM') signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ('RF') signal source for the transmitter and the local oscillator 'LO') signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal. As part of the demodulation of the down-converted FM receive signal, the binary transmit data is subtracted out. The FM transmit and receive signals are trinary (f.sub.-P, f.sub.c, f.sub.+P) and represent encoded binary data. The center frequency f.sub.c corresponds to an absence of a binary data signal transition, the lower peak frequency f.sub.-P corresponds to a negative binary data signal transition and the upper peak frequency f.sub.+P corresponds to a positive binary data signal transition.

Frequency modulator for data transceiver

A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ('FM') signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ('RF') signal source for the transmitter and the local oscillator ('LO') signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal. As part of the demodulation of the down-converted FM receive signal, the binary transmit data is subtracted out. The FM transmit and receive signals are trinary (f.sub.-P, f.sub.C, f.sub.+P) and represent encoded binary data. The center frequency f.sub.C corresponds to an absence of a binary data signal transition, the lower peak frequency f.sub.-P corresponds to a negative binary data signal transition and the upper peak frequency f.sub.+P corresponds to a positive binary data signal transition.

Data encoder/decoder for data transceiver

A full duplex data transceiver for transmitting and receiving frequency-modulated ('FM') signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ('RF') signal source for the transmitter and the local oscillator ('LO') signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal. As part of the demodulation of the down-converted FM receive signal, the binary transmit data is subtracted out.

Wireless data transceiver

A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ('FM') signals representing binary data includes at least one antenna and a single oscillator which serves as both the radio frequency ('RF') signal source for the transmitter and the local oscillator ('LO') signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is attenuated and coupled into the receiver along with a FM receive signal from the antenna, or alternatively is received via a separate receive antenna along with the FM receive signal, for mixing therewith to down-convert the FM receive signal. As part of the demodulation of the down-converted FM receive signal, the binary transmit data is subtracted out. The FM transmit and receive signals are trinary (f.sub.-P, f.sub.C, f.sub.+P) and represent encoded binary data. The center frequency f.sub.C corresponds to an absence of a binary data signal transition, the lower peak frequency f.sub.-P corresponds to a negative binary data signal transition and the upper peak frequency f.sub.+P corresponds to a positive binary data signal transition.

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Redwood City, CA, United States of America

Peter K Cripps