High dynamic range transceiver

This invention uses one or more cancellation modules to eliminate the transmitter leakage at the output of the receive antenna and prior the receiver circuitry so that the received signals can be analyzed without degradation in quality due to simultaneous operation of the transmitter and receiver. Each cancellation circuit could be limited to only 30-50 dB of rejection due to component mismatches and other circuit non-idealities. To obtain further cancellation, more than one cancellation circuit can be applied after the first low noise amplifier. The output of the low noise amplifier can be repeatedly mixed with additional cancellation signals “n” number of times such that the “n” low noise amplifier is mixed with the “nth” cancellation signal. For each additional cancellation signal added a 20-30 dB reduction in noise may be achieved such that cascading three or four cancellation signals from cancellation modules may produce a 150 dB gain.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates generally to wireless communication systems. Specifically, the invention relates to a cancellation system for use with wireless communication systems.

2. Related Art

Current communication systems usually support multi-mode wireless communication standards where the mobile device may operate and exist with a small form factor. Specifically, with the wide variety of communications standards that modern wireless systems are required to comply with, interference between the various wireless systems or sub-systems can be a true design challenge. Unlike the case of a single isolated wireless system, where possible interference between the transmitter and receiver can be handled by the use of different frequencies or different time slots, the co-existence of more than one system in close proximity can make the interference problem much more severe. In this case where more than one transmitter operate at the same frequency and same time slot, a receiver will detect undesired interference, which could overwhelm the desired signal and cause significant degradation in the quality of the received signal.

Moreover, the distance between the various antenna becomes a critical issue in such a complex communication environment where a number of transmitter and receiver systems are required to co-exist. In some cases, where the antenna are located in the Fresnel near-field region, that may result in constructive and destructive signal combining that may produce a large tone that would overpower the smaller reflected signal from the target. For example, assuming the simple case of a large transmitted tone to co-exist with the received signal at the same (or close to) frequency and time slot of the received signal. In practice, the desired received signal may be as low as 90 dB to 130 dB below the large tone. This result would effectively put the reflected signal level below the noise floor of most spectrum analyzers due to compression as well as the transmitter noise spectrum, which typically at best have approximately 60 dB of dynamic range (where dynamic range is generally defined as the difference between the highest and lowest power signals that the spectrum analyzer can simultaneously measure).

Typically, the magnitude of this large tone may be decreased by spacing the adjacent antennas farther apart; however, in many applications, space is premium such that the antenna cannot be spaced farther apart. This issue with simultaneous transmit and receiving problem is the same fundamental limit that forces majority of communication systems to operate as a “half-duplex” system, i.e. as only a transmitter or receiver at any point in time. Unless the frequency bands of the transmit signal and receiver signal are separated with enough margin to allow for a duplexer filter to be used, a physical realization of a “full-duplex” transceiver system is very difficult to realize. That is mainly due to the difficulty of receiving weak signals into a receiver in the existence of a strong interferer coming from the strong transmitted signal from the same system or another adjacent transmitter system that can be in proximity.

As an example of these problems inFIG. 1, a block diagram of an example of an implementation of a wireless transceiver100for use with a communication system is shown. The transceiver system100may include a first antenna102, a second antenna104, a transmitter106, a receiver108, a first frequency source110, and a second frequency source112. The transmitter106may be in signal communication with both the first antenna102and first frequency source110via signal paths114and116, respectively. Similarly, the receiver108may be in signal communication with both the second antenna104and second frequency source112via signal paths118and120, respectively. Additionally, the first antenna102may be in signal communication with the second antenna104via signal paths122.

In an example of operation, the transmitter106receives a frequency reference signal124from the first frequency source110via signal path116. The transmitter106then transmits a transmit signal126through the first antenna102which becomes signal128. The signal130is the transmitter leakage that directly couples to the second antenna104via signal path122.

The second antenna104receives the first portion130of the transmit signal126as well as the received signal132and passes the combined received signal134to the receiver108, via signal path118, which produces an receiver output signal136.

InFIG. 2, an example plot of the amplitude200versus frequency202of the receiver output signal200produced by the transceiver system100ofFIG. 1is shown. The receiver output signal204may include transmitter leakage206at frequency F0208(which would be the local oscillator frequency of the first frequency source110) and a secondary tone at frequency F1.

The transmitter leakage206is caused by the direct coupling from the transmit antenna to the receive antenna as shown inFIG. 1. The difference in amplitude intensity between the transmit leakage206and the received signal210is shown as A214. As an example, the difference between the transmitter leakage206and the received signal210may be as much as 90 to 130 dB which effectively places the received signals210below the noise floor coming from the transmitted signal. Additionally, because of jitter effects caused by the characteristics of the frequency source and the relatively small frequency and time difference between the transmitter leakage206and the received signal210, the transmitter leakage206may have a skirt216that effectively covers the received signal210and will, hence, make it impossible to recover the desired signal. As such, there is a need for a methodology to extend the dynamic range of transceiver system that overcomes the above mentioned problems.

SUMMARY

This invention transmits radio frequency energy that is also capable of receiving radio frequency energy and can eliminate the transmitter leakage by performing at least one cancellation process to improve the gain. An amplitude phase shift module and at least one power and phase detector modules are used to detect the reflected RF energy signals while acting to eliminate the transmitter leakage and received signals.

This invention may use a one or more cancellation modules to eliminate the transmitter leakage so that the received signals are analyzed. Each cancellation circuit could be limited to only 20-50 dB of rejection due to component mismatches and other circuit non-idealities. To obtain further cancellation, another cancellation circuit can be applied after the first low noise amplifier. The output of the low noise amplifier can be repeatedly mixed with additional cancellation signals “n” number of times such that the “n” low noise amplifier is mixed with the “nth” cancellation signal. For each additional cancellation signal added a 20-50 dB reduction in noise may be achieved such that cascading three or four cancellation signals from cancellation modules may produce a 150 dB gain.

DETAILED DESCRIPTION

The circuits, components, modules, and/or devices of the high dynamic range transceiver system300shown inFIG. 3are described in signal communication with each other, where the signal communication refers to any type of communication and/or connection between the circuits, components, modules, and/or devices that allows a circuit, component, module, and/or device to pass and/or receive signals and/or information from another circuit, component, module, and/or device.

The communication and/or connection may be along any signal path between the circuits, components, modules, and/or devices that allows signals and/or information to pass from one circuit, component, module, and/or device to another and includes wireless or wired signal paths. The signal paths may be physical pathways such as, for example, conductive wires, electromagnetic wave guides, attached and/or electromagnetic or mechanically coupled terminals, semi-conductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, signal paths may be non-physical such as free-space (in the case of electromagnetic propagation) or information paths through digital components where communication information is passed from one circuit, component, module, and/or device to another in varying digital formats without passing through a direct electromagnetic connection.

InFIG. 3, a block diagram of an example of an implementation of a transceiver system300is shown. The transceiver system300includes a first antenna302, a coupler304, a second antenna306, a frequency source308, a transmitter310, a receiver312, an amplitude-phase shift module314, a first power and phase detector module316, a second power and phase detector module318, a processor320, and a combiner322. The first antenna302and second antenna306may are capable of transmitting and receiving RF energy of the electromagnetic spectrum.

The first antenna302may be connected to a coupler304via path324. The transmitter310and the frequency source308may be connected via signal path326. The coupler304may be connected to the transmitter310via signal path328. The frequency source308may be an oscillator, a temperature controlled oscillator or any other type of frequency generating device. The signal path328may also be in signal communication along path330such that the bleeded signal332is sent to the amplitude-phase shift module314. The frequency source308generates signals to the transmitter310and may also be in signal communication with the receiver312via signal path334. The amplitude-phase shift module314may be in signal communication with the first power and phase detector module316and combiner322via signal path336; and in signal communication with the processor320via signal path338.

The processor320also may be in signal communication with the first power and phase detector module316via signal path340; and in signal communication with the second power and phase detector module318via signal path342. The second antenna306may be in signal communication with both the second power and phase detector module318and the combiner322via signal path336. The combiner322may be in signal communication with the receiver312via signal path346. Additionally, the first antenna302may be in signal communication with the second antenna306via signals368and370.

As an example, the first antenna302and second antenna306may both be RF energy antennas. The frequency reference signal346from the frequency source308, via signal path326sent to the transmitter310, may be used to upconvert and/or modulate a transmit signal348that is passed to the first antenna302via signal path324and a bleeded signal332is sent to the amplitude phase shift module314. In the alternative, the frequency source308may generate a signal sent along path348bypassing the transmitter310and sending the signal along path348to the coupler304. If a first received signal350arrives at the first antenna302, a coupler304acts to isolate the received signal350so that it is not passed to the transmitter310or to the amplitude phase shift module314.

Receiver312is a circuit, component, module, and/or device capable of receiving RF energy signals through the second antenna306and combiner322. The receiver312includes at least one mixer (not shown) that utilizes the bleeded signal332from the coupler304allowing the receiver312to subtract out the phase noise added by the transmitter310, frequency source308or both.

An optional path is for the frequency source308to output a signal directly to the receiver312. Although this optional path would not remove the phase noise generated by the transmitter310. It is appreciated that while only a receiver is shown inFIG. 3as receiver312, the scope of the invention could include utilizing a second transmit/receive module instead of only a receiver.

The frequency source308is a circuit, component, module, and/or device capable of producing the frequency reference signal346. The frequency source308may be, for example, a local oscillator or frequency synthesizer both of which are well known by those skilled in the art. The frequency source308may include, for example, a voltage controlled oscillator, temperature controlled oscillator, or voltage and temperature controlled oscillator.

Each of the first power and phase detector module316and second power and phase detector module318may be a circuit, component, module, and/or device capable of detecting the power amplitude and/or the phase of an amplitude phase shift module output signal352from the amplitude phase shift module314and a second received signal354from the second antenna306. Both the first power and phase detector module316and the second power and phase detector module318may include one or more power detector sensor circuits and/or phase detector sensor circuits.

In an example operation, the first power and phase detector module316would produce a first power and phase detector module signal356in response to detecting the power and/or phase of the amplitude phase shift module output signal352. The first power and phase detector module316may send to the processor analog or digital data on the amplitude and phase of the amplitude phase shift module output signal352. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor320.

Similarly, the second power and phase detector module318produces a second power and phase detector module signal356in response to detecting the power and/or phase of the second received signal354. The first power and phase detector module signal356may send to the processor analog or digital data on the amplitude and phase of the received signal354and second power and phase detector module signal356would then include measured power and/or phase information data passed to the processor320via signal paths340and342, respectively. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor320.

The processor320is a circuit, component, module, and/or device capable of receiving the first power and phase detector module signal356and second power and phase detector module signal358and, in response, generate an amplitude phase shift module control signal360that would control the amplitude-phase shift module314via signal path338. The processor320is capable of determining how to modify the amplitude and/or phase of the transmit signal352with the amplitude phase shift module314in order to increase resolution and dynamic range of the receiver output signal362based on the measured power and/or phase information data provided by the first power and phase detector module signal356and second power and phase detector module signal358. The processor320may be, for example, a central processing unit (“CPU”), microprocessor, microcontroller, controller, digital signal processor (“DSP”), reduced instruction set processor (“RISC processor”), application specific integrated circuit (“ASIC”), or other similar types of devices.

The amplitude-phase shift module314is a circuit, component, module, and/or device capable of receiving the amplitude phase shift module control signal360and, in response, adjusting the transmit signal332in amplitude, phase, or both, to produce the amplitude phase shift module output signal352which is passed to the combiner322via signal path336. The combiner322may be a circuit, component, module, and/or device capable of combining the amplitude phase shift module output signal352with the second received signal354to produce the receiver input signal364. The combiner322may be, for example, a summation circuit or coupler.

This sampling and routing of signals acts to cancel via cancellation circuitry366the transmitter leakage of received signals368and signal370. Thus, the system is designed to cancel the transmitter leakage from signal368leaving only the received signals370. It is this modified signal364that is passed to the receiver312and then onto the communication system via signal path362for output to a user.

The transceiver system300produces the RF energy when the frequency transmit signals348are generated. The input signal332may be externally generated, preprogrammed or generated by the transmitter310. The output signal348is passed to the first antenna302via signal path328. The first antenna302transmits the transmit output signal348towards the medium of the communication channel, which could be air. A portion368of the transmitted output signal348may be directly coupled to the second antenna306via signal path372.

A portion332of the transmitted output signal348captured via a coupler304or any similar device is fed to the cancellation system, where its amplitude and phase are going to be adjusted to accurately perform cancellation. Ideally, the coupler304acts to allow transmission of output signals, but does not pass received signals350to other circuitry such as the amplitude phase shift module314.

The second antenna306receives the leakage signal368of the transmitted output signal348and passes the combined received signal360to both the second power and phase detector module318and the combiner322via signal path336. The second power and phase detector module318samples part of the combined received signal354, measures the power amplitude and/or phase of the received signal354from the sample, and sends the measured information data to the processor320via the second power and phase detector module signal358along signal path342.

The processor320receives the output of the power and phase detector module318and the output of the first power and phase detector module316. The processor320receives output signal358and output signal356and adjusts output signal356by cancelling out the signal352that is output from the amplitude and phase shift module314to the combiner322.

The objective of the processor is to equalize by feedback, both in amplitude and phase, the signals352and354. The processor320operates as a feedback adjustment. Signal358is a measured signal. However, signal352can be adjusted by signal360. By equalizing and cancelling the two signals coming out of the combiner322, the transmitter leakage368can be cancelled and the system is then left with the received signals354that are passed to the receiver312.

The combiner322receives the received signal354and combines it with amplitude phase shift module output signal352to produce the receiver input signal364that is passed to the receiver312via signal path346. The receiver312then receives the receiver input signal364and produces the receiver output signal362.

When the transmit input signal374is sent along signal path334to the receiver312, the frequency source308will act as a local oscillator to the receiver312such that the phase noise from the frequency source308can be subtracted from the signal364so that the receiver output signal362can be generated.

The circuits, components, modules, and/or devices of the high dynamic range transceiver system400shown inFIG. 4are described in signal communication with each other, where the signal communication refers to any type of communication and/or connection between the circuits, components, modules, and/or devices that allows a circuit, component, module, and/or device to pass and/or receive signals and/or information from another circuit, component, module, and/or device.

The communication and/or connection may be along any signal path between the circuits, components, modules, and/or devices that allows signals and/or information to pass from one circuit, component, module, and/or device to another and includes wireless or wired signal paths. The signal paths may be physical pathways such as, for example, conductive wires, electromagnetic wave guides, attached and/or electromagnetic or mechanically coupled terminals, semi-conductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, signal paths may be non-physical such as free-space (in the case of electromagnetic propagation) or information paths through digital components where communication information is passed from one circuit, component, module, and/or device to another in varying digital formats without passing through a direct electromagnetic connection.

InFIG. 4, a block diagram of an example of an implementation of a transceiver system400is shown. The transceiver system400includes a first antenna402, a coupler404, a second antenna406, a frequency source408, a transmitter410, a receiver412, an amplitude-phase shift module414, a power and phase detector module416, a processor420, and a combiner422. The first antenna402and second antenna406may are capable of transmitting and receiving RF energy of the electromagnetic spectrum.

The first antenna402may be connected to a coupler404via path424. The transmitter410and the frequency source408may be connected via signal path426. The coupler404may be connected to the transmitter410via signal path428. The frequency source408may be an oscillator, a temperature controlled oscillator or any other type of frequency generating device. The signal path428may also be in signal communication along path430such that the bleeded signal432is sent to the amplitude-phase shift module414. The frequency source408generates signals to the transmitter410and may also be in signal communication with the receiver412via signal path434. The amplitude-phase shift module414may be in signal communication with the combiner422via signal path436; and in signal communication with the processor420via signal path438.

The processor420also may be in signal communication with the power and phase detector module416via signal path440. The second antenna406may be in signal communication with the combiner422via signal path436. The combiner422may be in signal communication with the receiver412via signal path446and the power and phase detector module416via signal path441. Additionally, the first antenna402may be in signal communication with the second antenna406via signals468and470.

As an example, the first antenna402and second antenna406may both be RF energy antennas. The frequency reference signal446from the frequency source408, via signal path426sent to the transmitter410, may be used to upconvert and/or modulate a transmit signal448that is passed to the first antenna402via signal path424and a bleeded signal432is sent to the amplitude phase shift module414. In the alternative, the frequency source408may generate a signal sent along path448bypassing the transmitter410and sending the signal along path448to the coupler404. If a first received signal450arrives at the first antenna402, a coupler404acts to isolate the received signal450so that it is not passed to the transmitter410or to the amplitude phase shift module414.

Receiver412is a circuit, component, module, and/or device capable of receiving RF signals through the second antenna406and combiner422. The receiver412includes at least one mixer (not shown) that utilizes the bleeded signal432from the coupler404allowing the receiver412to subtract out the phase noise added by the transmitter410, frequency source408or both.

An optional path is for the frequency source408to output a signal directly to the receiver412. Although this optional path would not remove the phase noise generated by the transmitter410. It is appreciated that while only a receiver is shown inFIG. 4as receiver412, the scope of the invention could include utilizing a second transmit/receive module instead of only a receiver.

The frequency source408is a circuit, component, module, and/or device capable of producing the frequency reference signal446. The frequency source408may be, for example, a local oscillator or frequency synthesizer both of which are well known by those skilled in the art. The frequency source408may include, for example, a voltage controlled oscillator, temperature controlled oscillator, or voltage and temperature controlled oscillator.

The power and phase detector module416may be a circuit, component, module, and/or device capable of detecting the power amplitude and/or the phase of an amplitude phase shift module output signal452from the amplitude phase shift module414and a second received signal454from the second antenna406. The power and phase detector module416may include one or more power detector sensor circuits and/or phase detector sensor circuits.

In an example operation, the power and phase detector module416would produce a power and phase detector module signal456in response to detecting the power and/or phase of the amplitude phase shift module output signal452. The power and phase detector module416may send to the processor analog or digital data on the amplitude and phase of the amplitude phase shift module output signal452. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor420.

The power and phase detector module signal456may send to the processor analog or digital data on the amplitude and phase of the received signal454and second power and phase detector module signal456would then include measured power and/or phase information data passed to the processor420via signal paths440. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor420.

The processor420is a circuit, component, module, and/or device capable of receiving the power and phase detector module signal456and, in response, generate an amplitude phase shift module control signal460that would control the amplitude-phase shift module414via signal path438. The processor420is capable of determining how to modify the amplitude and/or phase of the transmit signal432with the amplitude phase shift module414in order to increase resolution and dynamic range of the receiver output signal462based on the measured power and/or phase information data provided by the power and phase detector module signal456. The processor420may be, for example, a central processing unit (“CPU”), microprocessor, microcontroller, controller, digital signal processor (“DSP”), reduced instruction set processor (“RISC processor”), application specific integrated circuit (“ASIC”), or other similar types of devices.

The amplitude-phase shift module414is a circuit, component, module, and/or device capable of receiving the amplitude phase shift module control signal460and, in response, adjusting the transmit signal432in amplitude, phase, or both, to produce the amplitude phase shift module output signal452which is passed to the combiner422via signal path436. The combiner422may be a circuit, component, module, and/or device capable of combining the amplitude phase shift module output signal452with the second received signal454to produce the receiver input signal464. The combiner422may be, for example, a summation circuit or coupler.

This sampling and routing of signals acts to cancel via cancellation circuitry466the transmitter leakage of received signals468and signal470. Thus, the system is designed to cancel the transmitter leakage from signal468leaving only the received signals470. It is this modified signal464that is passed to the receiver412and then onto the communication system via signal path462for output to a user.

The transceiver system400produces the RF energy when the frequency transmit signals448are generated. The input signal432may be externally generated, preprogrammed or generated by the transmitter410. The output signal448is passed to the first antenna402via signal path428. The first antenna402transmits the transmit output signal448towards the medium of the communication channel, which could be air. A portion468of the transmitted output signal448may be directly coupled to the second antenna406via signal path472.

A portion432of the transmitted output signal448captured via a coupler404or any similar device is fed to the cancellation system, where its amplitude and phase are going to be adjusted to accurately perform cancellation. Ideally, the coupler404acts to allow transmission of output signals, but does not pass received signals450to other circuitry such as the amplitude phase shift module414.

The second antenna406receives the leakage signal468of the transmitted output signal448and passes the combined received signal (transmit signal plus leakage)454to the combiner422via signal path436. The power and phase detector module416samples part of the combined received signal454, measures the power amplitude and/or phase of the received signal454from the sample, and sends the measured information data to the processor420via the power and phase detector module signal456along signal path440.

The processor420receives output signal456and adjusts output signal460by cancelling out the signal452that is output from the amplitude and phase shift module414that is sent to the combiner422.

The objective of the processor is to equalize by feedback signal456. The processor420operates as a feedback adjustment. However, signal452can be adjusted by signal460. By equalizing and cancelling the two signals coming out of the combiner422, the transmitter leakage468can be cancelled and the system is then left with the received signals354that are passed to the receiver412.

The combiner422receives the received signal454and combines it with amplitude phase shift module output signal452to produce the receiver input signal464that is passed to the receiver412via signal path446. The receiver412then receives the receiver input signal464and produces the receiver output signal462.

When the transmit input signal474is sent along signal path434to the receiver412, the frequency source408will act as a local oscillator to the receiver412such that the phase noise from the frequency source408can be subtracted from the signal464so that the receiver output signal462can be generated.

The circuits, components, modules, and/or devices of the high dynamic range transceiver system500shown inFIG. 5are described in signal communication with each other, where the signal communication refers to any type of communication and/or connection between the circuits, components, modules, and/or devices that allows a circuit, component, module, and/or device to pass and/or receive signals and/or information from another circuit, component, module, and/or device.

The communication and/or connection may be along any signal path between the circuits, components, modules, and/or devices that allows signals and/or information to pass from one circuit, component, module, and/or device to another and includes wireless or wired signal paths. The signal paths may be physical pathways such as, for example, conductive wires, electromagnetic wave guides, attached and/or electromagnetic or mechanically coupled terminals, semi-conductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, signal paths may be non-physical such as free-space (in the case of electromagnetic propagation) or information paths through digital components where communication information is passed from one circuit, component, module, and/or device to another in varying digital formats without passing through a direct electromagnetic connection.

InFIG. 5, a block diagram of an example of an implementation of a transceiver system500is shown. The transceiver system500includes a first antenna502, a coupler504, a second antenna506, a frequency source508, a transmitter510, a receiver512, an amplitude-phase shift module514, a first power and phase detector module516, a second power and phase detector module518, a third power and phase detector module519, a processor520, and a combiner522. The first antenna502and second antenna506may are capable of transmitting and receiving RF energy of the electromagnetic spectrum.

The first antenna502may be connected to a coupler504via path524. The transmitter510and the frequency source508may be connected via signal path526. The coupler504may be connected to the transmitter510via signal path528. The frequency source508may be an oscillator, a temperature controlled oscillator or any other type of frequency generating device. The signal path528may also be in signal communication along path530such that the bleeded signal532is sent to the amplitude-phase shift module514. The frequency source508generates signals to the transmitter510and may also be in signal communication with the receiver512via signal path534. The amplitude-phase shift module514may be in signal communication with the first power and phase detector module516and combiner522via signal path536; and in signal communication with the processor520via signal path538.

The processor520also may be in signal communication with the first power and phase detector module516via signal path540; in signal communication with the second power and phase detector module518via signal path542; and in signal communication with the third power and phase detector module519via signal path543. The second antenna506may be in signal communication with both the combiner522via signal path536; and the third power and phase detector module519via signal path546and545. The combiner522may be in signal communication with the receiver512via signal path546. Additionally, the first antenna502may be in signal communication with the second antenna506via signals568and570.

As an example, the first antenna502and second antenna506may both be RF energy antennas. The frequency reference signal546from the frequency source508, via signal path526sent to the transmitter510, may be used to upconvert and/or modulate a transmit signal548that is passed to the first antenna502via signal path524and a bleeded signal532is sent to the amplitude phase shift module514. In the alternative, the frequency source508may generate a signal sent along path548bypassing the transmitter510and sending the signal along path548to the coupler504. If a first received signal550arrives at the first antenna502, a coupler504acts to isolate the received signal550so that it is not passed to the transmitter510or to the amplitude phase shift module514.

Receiver512is a circuit, component, module, and/or device capable of receiving RF signals through the second antenna506and combiner522. The receiver512includes at least one mixer (not shown) that utilizes the bleeded signal532from the coupler504allowing the receiver512to subtract out the phase noise added by the transmitter510, frequency source508or both.

An optional path is for the frequency source508to output a signal directly to the receiver512. Although this optional path would not remove the phase noise generated by the transmitter510. It is appreciated that while only a receiver is shown inFIG. 5as receiver512, the scope of the invention could include utilizing a second transmit/receive module instead of only a receiver.

The frequency source508is a circuit, component, module, and/or device capable of producing the frequency reference signal546. The frequency source508may be, for example, a local oscillator or frequency synthesizer both of which are well known by those skilled in the art. The frequency source508may include, for example, a voltage controlled oscillator, temperature controlled oscillator, or voltage and temperature controlled oscillator.

Each of the first power and phase detector module516and second power and phase detector module518may be a circuit, component, module, and/or device capable of detecting the power amplitude and/or the phase of an amplitude phase shift module output signal552from the amplitude phase shift module514and a second received signal554from the second antenna506. Both the first power and phase detector module516and the second power and phase detector module518may include one or more power detector sensor circuits and/or phase detector sensor circuits.

In an example operation, the first power and phase detector module516would produce a first power and phase detector module signal556in response to detecting the power and/or phase of the amplitude phase shift module output signal552. The first power and phase detector module516may send to the processor analog or digital data on the amplitude and phase of the amplitude phase shift module output signal552. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor520.

Similarly, the second power and phase detector module518produces a second power and phase detector module signal556in response to detecting the power and/or phase of the second received signal554. The first power and phase detector module signal556may send to the processor analog or digital data on the amplitude and phase of the received signal554and second power and phase detector module signal556would then include measured power and/or phase information data passed to the processor520via signal paths540and542, respectively. If analog data is sent an analog-digital converter is needed before the signal is passed to the processor520.

The processor520is a circuit, component, module, and/or device capable of receiving the first power and phase detector module signal556and second power and phase detector module signal558and, in response, generate an amplitude phase shift module control signal560that would control the amplitude-phase shift module514via signal path538. The processor520is capable of determining how to modify the amplitude and/or phase of the transmit signal532with the amplitude phase shift module514in order to increase resolution and dynamic range of the receiver output signal562based on the measured power and/or phase information data provided by the first power and phase detector module signal556and second power and phase detector module signal558. The processor520may be, for example, a central processing unit (“CPU”), microprocessor, microcontroller, controller, digital signal processor (“DSP”), reduced instruction set processor (“RISC processor”), application specific integrated circuit (“ASIC”), or other similar types of devices.

The amplitude-phase shift module514is a circuit, component, module, and/or device capable of receiving the amplitude phase shift module control signal560and, in response, adjusting the transmit signal532in amplitude, phase, or both, to produce the amplitude phase shift module output signal552which is passed to the combiner522via signal path536. The combiner522may be a circuit, component, module, and/or device capable of combining the amplitude phase shift module output signal552with the second received signal554to produce the receiver input signal564. The combiner522may be, for example, a summation circuit or coupler.

This sampling and routing of signals acts to cancel via cancellation circuitry566the transmitter leakage of received signals568and signal570. Thus, the system is designed to cancel the transmitter leakage from signal568leaving only the received signals570. It is this modified signal564that is passed to the receiver512and then onto the communication system via signal path562for output to a user.

The transceiver system500produces the RF energy when the frequency transmit signals548are generated. The input signal532may be externally generated, preprogrammed or generated by the transmitter510. The output signal548is passed to the first antenna502via signal path528. The first antenna502transmits the transmit output signal548towards the medium of the communication channel, which could be air. A portion568of the transmitted output signal548may be directly coupled to the second antenna506via signal path572.

A portion532of the transmitted output signal548captured via a coupler404or any similar device is fed to the cancellation system, where its amplitude and phase are going to be adjusted to accurately perform cancellation. Ideally, the coupler504acts to allow transmission of output signals, but does not pass received signals550to other circuitry such as the amplitude phase shift module514.

The second antenna506receives the leakage signal568of the transmitted transmit output signal548and passes the combined received signal570to both the second power and phase detector module518and the combiner522via signal path536. The second power and phase detector module518samples part of the combined received signal554, measures the power amplitude and/or phase of the received signal554from the sample, and sends the measured information data to the processor520via the second power and phase detector module signal558along signal path542.

The processor520receives the output of the power and phase detector module518and the output of the first power and phase detector module516. The processor520receives output signal558and output signal556and adjusts output signal556by cancelling out the signal552that is output from the amplitude and phase shift module514to the combiner522.

The objective of the processor is to equalize by feedback signals556and558. The processor520operates as a feedback adjustment. Signal558is a measured signal. However, signal552can be adjusted by signal560. By equalizing and cancelling the two signals coming out of the combiner522, the transmitter leakage568can be cancelled and the system is then left with the received signals554that are passed to the receiver512.

The combiner522receives the received signal554and combines it with amplitude phase shift module output signal552to produce the receiver input signal564that is passed to the receiver512via signal path546. The receiver512then receives the receiver input signal564and produces the receiver output signal562.

When the transmit input signal574is sent along signal path534to the receiver512, the frequency source508will act as a local oscillator to the receiver512such that the phase noise from the frequency source508can be subtracted from the signal564so that the receiver output signal562can be generated.

InFIG. 6, a plot of an example of a received signal600as a function of amplitude602versus frequency604is shown. The received signal600is an example of the received signals370,470and570as shown inFIGS. 3-5. The received signal600may include transmitter leakage606, at frequency F0608(which would be the frequency of the frequency sources308,408and508), and received signals600at frequency F1610.

The difference in amplitude intensity between the transmitter leakage606and the received signal600is shown as A612. As an example, the difference between the transmit leakage606and the received signal600which may be initially about 90 dB to 130 dB, which would again effectively place the received signal600below the skirts614. Additionally, because of jitter effects caused by the characteristics of both the frequency sources, the transmitter leakage606may initially have a skirt614that effectively covers the received signal600.

However, once the cancellation is performed both the transmit leakage and its skirts614by the cancellation amount B616so that the transmit leakage is reduced to a new transmit leakage618. Thus, the received signal600is now above the new skirts620associated with the new transmit leakage618.

The reduction of the transmit leakage606is caused by the compensation and canceling effects of combining the amplitude phase shift module output signal352with the received signal370(when compared to the embodiment inFIG. 3). As stated above, the processor320, based on the measured values of the first power and phase detector module signal356and second power and phase detector module signal358, determines how best to modify the transmit signal332to create the amplitude phase shift module output signal352so as to cancel out the transmit leakage368when the amplitude phase shift module output signal352is combined with the received signal354. Additionally, the transmit leakage368may be reduced further in this approach because the transceiver system300utilizes a signal frequency source308as a frequency reference to the receiver312via path334, which greatly reduces the frequency uncertainty associated with the system compared to known approaches.

To achieve a higher dynamic range, more cancellation is needed. Here, the problem is solved by using a cancellation scheme providing a wide dynamic range exceeding 150 dB.FIG. 7illustrates a cascading of the cancellation modules applying the cancellation scheme repeating the cancellation scheme. Each cancellation circuit could be limited to only 20-30 dB of rejection due to component mismatches and other circuit non-idealities. To obtain further cancellation, another cancellation circuit can be applied after the first low noise amplifier. Then the same can be done after the second low noise amplifier. Theoretically, there is no limit to the number of cancellation circuits that could be used in one chain.

FIG. 7illustrates such a cascading effect. The received signal700is combined702with a first cancellation signal704and the combined signal is passed to a low noise amplifier706. The output of the low noise amplifier706can be combined708the second cancellation signal710. The combined signal708is passed to a second low noise amplifier712. The output of the low noise amplifier712can be combined714with the third cancellation signal716. The output of the low noise amplifier712can be repeatedly combined with additional cancellation signals “n” number of times such that the “n” low noise amplifier718is combined720with the “n” cancellation signal722. For each additional cancellation signal may add a 20-50 dB reduction in noise may be achieved such that cascading three or four cancellation signals from cancellation modules may produce a 150 dB gain.

FIG. 8illustrates the cancellation process set forth inFIG. 7and performed by the operation of the transceiver system as shown inFIG. 3, 4 or 5. The process begins when the transceiver system transmits an output signal at air and a medium with another permittivity from a transmit antenna800. The antenna receives a portion of the receive output signal802and the receive antenna as described in circuitry ofFIG. 3, 4 or 5. The power and phase detector module then measures the amplitude and/or phase of the received signal (for example, as shown as the received signal358inFIG. 3) from the receive antenna804. The amplitude phase shift module then adjusts the received signal from the receive antenna to cancel (or reduce the amplitude of) the transmit leakage within the received signal from the antenna. The amplitude phase shift module adjusts the bleeded signal806based on the amplitude phase shift module control signal from the processor, where the processor receives measurement information from the first power and phase detector module and second power and phase detector module. The process808then combines the bleeded signal before the transmitter antenna with the received signal from the receive antenna. The cancellation is then performed810. The cancellation is repeated as shown inFIG. 7until the desired number of iterations is reached.