Transverter control mechanism for a wireless modem in a broadband access system

• US 20020159511A1
• Filed: 01/26/2001
• Published: 10/31/2002
• Est. Priority Date: 01/26/2000
• Status: Active Grant

• Current Assignee: Imago Research Limited Liability Company
• Original Assignee: VYYO, Ltd.
• Inventors: Hendler, Hillel, Asia, Raul, Wilson, Eric K.
• Granted Patent: US 7,027,776 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence

Abstract

A system and method for controlling a transverter from a wireless modem unit (WMU). A WMU delivers a control signal to a transceiver. This signal is outside the IF signal data range (preferably below 11 MHz). The signal is carried on the cable between the transceiver and the WMU. This signal is detected by the transceiver, and determines the timing and the control information. The signal is ASK modulated to enable low data rate transfer of messages between the WMU and the transceiver. The control signal is detected at the transverter using a detector circuit. Additionally, specific transverter detection circuits are disclosed to detect the control signal.

Claims

1. A wireless modem unit (WMU) comprising:

a processor;

a modulator controlled by the processor;

a pre-preamble modulator controlled by the processor;

a summation circuit connected to receive an output from the modulator and an output from the pre-preamble modulator; and

an output stage connected to an output of the summation circuit;

wherein a pre-preamble signal generated by the pre-preamble modulator alerts the output stage of an impending data burst.

2. The wireless modem unit of claim 1, wherein the pre-preamble modulator produces a carrier at a frequency outside of a normal data band.

3. The wireless modem unit of claim 2, wherein the carrier is Amplitude Shift Key modulated.

4. The wireless modem unit of claim 3, further comprising a diplexer connected between the output stage and a transverter.

5. A transverter control system comprising:

a diplexer connected to a wireless modem unit (WMU) and receiving a downstream signal and outputting an upstream signal;

a transmission path comprising;

a notch filter having an input connected to the upstream signal;

an upconverter connected to the notch filter; and

a transmitter switch connected to an output of the upconverter;

a control path comprising;

a band pass filter having an input connected to the upstream signal; and

a detector and demodulator unit connected to the band pass filter;

wherein the detector and demodulator unit outputs a control signal to control the upconverter and the transmitter switch based on a pre-preamble signal received from the wireless modem unit.

6. A transverter control system for a wireless modem, the system comprising:

a wireless modem unit (WMU) comprising;

a processor;

a modulator controlled by the processor;

a pre-preamble modulator controlled by the processor;

a summation circuit connected to receive an output from the modulator and an output from the pre-preamble modulator; and

an output stage connected to an output of the summation circuit;

wherein a pre-preamble signal generated by the pre-preamble modulator alerts the output stage of an impending data burst; and

a transverter control system comprising;

a diplexer connected to a wireless modem unit (WMU) and receiving a downstream signal and outputting an upstream signal;

a transmission path comprising;

a notch filter having an input connected to the upstream signal;

an upconverter connected to the notch filter; and

a transmitter switch connected to an output of the upconverter;

a control path comprising;

a band pass filter having an input connected to the upstream signal; and

a detector and demodulator unit connected to the band pass filter;

wherein the detector and demodulator unit outputs a control signal to control the upconverter and the transmitter switch based on a pre-preamble signal received from the wireless modem unit.

7. A method of control of a transverter in a wireless access system, the method comprising:

creating a pre-preamble signal and a control data signal in a wireless modem unit (WMU);

transmitting the pre-preamble signal as a notification signal;

transmitting the control data signal to the transverter;

detecting the pre-preamble signal at the transverter, and in response to the detected signal, disabling a transmitter switch;

decoding and processing the control data signal; and

resetting the transmitter switch.

8. A method of transverter control, the method comprising:

programming a modem to a low frequency;

transmitting control data at the low frequency;

re-programming the modem to an appropriate frequency to transmit actual data;

modifying transverter parameters in response to the control data; and

transmitting the actual data via the transverter.

9. A transverter pre-preamble signal detection circuit, the circuit comprising:

a tap connected to an upstream signal path;

an amplifier connected to a tap output;

a detector connected to an amplifier output;

a comparator having a first input and a second input, the first input connected to a detector output, and the second input connected to a reference voltage; and

a one-shot circuit connected to an output of the comparator, the one-shot controlling a power amplifier.

10. A transverter pre-preamble signal detection circuit having an automatic reference level determination, the circuit comprising:

a tap connected to an upstream signal path;

an amplifier connected to a tap output;

a detector connected to an amplifier output;

a first filter having a fast response time connected to a detector output;

a second filter having a slow response time connected to the detector output;

a first comparator having a first input connected to the first filter and a second input connected to the second filter; and

a one-shot circuit connected to an output of the first comparator, the one-shot circuit comprising;

a diode;

a low pass filter connected to the diode;

a reference voltage source; and

a second comparator having a first input connected to the reference voltage source, and a second input connected to the low pass filter.

11. A transverter pre-preamble signal detection circuit, the circuit comprising:

a tap connected to an upstream signal path;

a band pass filter connected to the tap;

an amplifier connected to a band pass filter output;

a detector connected to an amplifier output; and

a comparator having a first input and a second input, the first input connected to a detector output, and the second input connected to a reference voltage;

wherein the detector circuits detects control commands sent from a modem which are outside of a passband of the IF to RF conversions of the modem.