Apparatus and method for transmitting and receiving multiple radio signals over a single antenna

• US 7,894,779 B2
• Filed: 06/19/2007
• Issued: 02/22/2011
• Est. Priority Date: 06/22/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Meiyappan, Palaniappan, Wilson, Chad E., Malaga, Alfonso
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): Bilodeau; David
• Application Number:
  US11/765,207
• Publication Number:
  US 20080107093A1
• Time in Patent Office: 1,344 Days
• Field of Search: 455/78, 455/83, 455/553.1
• US Class Current: 455/83
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

An apparatus for transmitting and receiving multiple radio frequencies simultaneously over a single antenna is provided. The apparatus comprises a transmitter signal combining apparatus configured to communicatively couple with a plurality of transmitters, wherein the transmitter signal combining apparatus is configured to output a transmission signal based on any signals received from the plurality of transmitters. The apparatus also includes at least one transmit/receive signal duplexer coupled to the transmitter signal combining apparatus and configured to provide the transmission signal to an antenna, wherein the antenna receives an incoming radio frequency (RF) signal. Additionally, the apparatus includes a signal separation apparatus coupled to the at least one transmit/receive signal duplexer and configured to receive the incoming RF signal and provide the incoming RF signal to at least one receiver. Wherein the at least one transmit/receive signal duplexer is further configured to provide the incoming RF signal to the signal separation apparatus, and limit a direct coupling of the transmission signal into the signal separation apparatus.

Claims

1. An apparatus for transmitting and receiving multiple radio frequencies simultaneously over a single antenna, the apparatus comprising:

a transmitter signal combining apparatus configured to communicatively couple with a plurality of transmitters, wherein the transmitter signal combining apparatus is configured to output a transmission signal based on any signals received from the plurality of transmitters;

at least one transmit/receive signal duplexer coupled to the transmitter signal combining apparatus and configured to provide the transmission signal to an antenna, wherein the antenna is also configured to sense an incoming radio frequency (RF) signal;

a front end of a plurality of receivers coupled to the at least one transmit/receive signal duplexer;

a signal suppressor configured to monitor the transmission signal and cancel at least a portion of a transmission signal component that has coupled to the incoming RF signal based on monitoring the transmission signal, wherein the signal suppressor cancels the at least a portion of a transmission signal component prior to an amplifier in the front end of the plurality of receivers;

wherein the at least one transmit/receive signal duplexer is further configured to provide the incoming RF signal to the signal suppressor, and limit a direct coupling of the transmission signal into the signal suppressor;

a tunable notch filter configured to have the incoming RF signal coupled therethrough after the incoming RF signal passes through the at least one transmit/receive signal duplexer, the tunable notch filter configured to reject a frequency of one of the plurality of transmitters that is currently transmitting, wherein the tunable notch filter is coupled to the incoming RF signal prior to the amplifier in the front end of the plurality of receivers; and

a plurality of notch filters, each of the plurality of notch filters coupled to an output of one of the plurality of transmitters and configured to filter out a frequency of one of the plurality of receivers.

2. The apparatus of claim 1, wherein the at least one receiver receives incoming RF signals on at least a first frequency channel and a second frequency channel;

and

wherein a first transmitter of the plurality of transmitters generates signals using the first frequency channel, and wherein a second transmitter of the plurality of transmitters generates signals using the second frequency channel.

3. The apparatus of claim 1, further comprising:

a signal separation apparatus configured to split the incoming RF signal for distribution to at least a first receiver and a second receiver.

4. The apparatus of claim 1, further comprising:

an RF power coupler configured to measure an output of the transmitter signal combining apparatus;

a transmitter control logic coupled to the RF power coupler and the plurality of transmitters; and

wherein the transmitter control logic is configured to adjust a power of one or more of the plurality of transmitters based on information obtained by the RF power coupler.

5. The apparatus of claim 4, wherein the transmitter control logic is further configured to adjust a power of one or more of the plurality of transmitters based on information obtained by the RF power coupler to compensate for a power roll off of the transmitter signal combining apparatus.

6. The apparatus of claim 4, further comprising:

a calibration table memory, wherein the transmitter control logic is further configured to store information obtained by the RF power coupler into a calibration table memory.

7. The apparatus of claim 1, further comprising:

a variable attenuator coupled to the at least one transmit/receive signal duplexer, wherein the tunable notch filter is coupled to the variable attenuator;

a receiver control logic coupled to the variable attenuator and the tunable notch filter, wherein the receiver control logic tunes one or both of the variable attenuator and the tunable notch filter based on transmissions from the plurality of transmitters.

8. An apparatus for transmitting and receiving multiple frequencies on a single antenna comprising:

a transmitter signal combining apparatus configured to communicatively couple to a plurality of transmitters and to sum signals from the plurality of transmitters, the transmitter signal combining apparatus configured to communicatively couple to an antenna;

a signal suppressor configured to monitor a transmit signal from at least one of the plurality of transmitters to obtain a reference signal and cancel at least a portion of a transmit signal component in a receive signal based on transmissions from the plurality of transmitters;

a front end of a plurality of receivers coupled to the signal suppressor, wherein the signal suppressor cancels the at least a portion of a transmission signal component prior to an amplifier in the front end of the plurality of receivers;

wherein the receive signal is coupled from the antenna to the plurality of receivers, each of the plurality of receivers configured to receive at a frequency of one of the plurality of transmitters;

a tunable notch filter configured to have the receive signal coupled therethrough, the tunable notch filter configured to reject a frequency of one of the plurality of transmitters that is currently transmitting, wherein the tunable notch filter is coupled to the receive signal prior to the amplifier in the front end of the plurality of receivers; and

a plurality of notch filters, each of the plurality of notch filters coupled to an output of one of the plurality of transmitters and configured to filter out a frequency of one of the plurality of receivers.

9. The apparatus of claim 8, wherein the signal suppressor further comprises:

an adjustable phase shifter for adjusting the phase of the reference signal such that the adjusted reference signal substantially opposes a phase of the transmit signal component in the receive signal.

10. The apparatus of claim 9, wherein the signal suppressor further comprises:

an adaptive controller configured to monitor the receive signal and adjust the reference signal based on the receive signal.

11. The apparatus of claim 8, further comprising at least one transmit/receive signal duplexer coupled to the antenna and configured to provide the transmit signal from the combiner to the antenna, and further configured to provide the receive signal from the antenna to the plurality of receivers.

12. The apparatus of claim 11, wherein the signal suppressor further comprises:

a variable attenuator for adjusting the amplitude of the reference signal such that the adjusted reference signal is similar in power to the transmit signal component in the receive signal.

13. A method of transmitting and receiving multiple frequencies simultaneously on a single antenna, the method comprising:

receiving a receive signal at a first frequency over an antenna through a receive path via a transmit/receive signal duplexer coupled to the antenna, the receive path comprising a plurality of receivers coupled to the transmit/receive signal duplexer;

transmitting a transmit signal through a transmit path at a second frequency over the antenna, the transmit path comprising a plurality of transmitters coupled to a transmitter signal combining apparatus, wherein the transmitter signal combining apparatus is coupled to the transmit/receive signal duplexer;

monitoring the transmit signal in the transmit path to obtain a reference signal;

canceling from the receive path at least part of any leakage noise in the receive signal with the reference signal, wherein leakage noise is a portion of the transmit signal that is coupled into the receive signal; and

canceling from the transmit path, prior to the transmitter signal combining apparatus, noise in the transmit signal at the first frequency.

14. The method of claim 13, further comprising:

adjusting the reference signal based on feedback from the receive signal.

15. The method of claim 14, wherein adjusting adjusts a phase of the reference signal.

16. The method of claim 14, wherein adjusting adjusts an amplitude of the reference signal.

17. The method of claim 13, further comprising:

monitoring the receive signal to obtain uncancelled noise; and

adjusting the reference signal based on the uncancelled noise.

18. The method of claim 13, further comprising:

rejecting components of the second frequency in the receive signal.