Multi-standard transceiver, device and method

A multi-standard transceiver includes a first subunit configured to perform signal processing according to a first communication standard and a second subunit configured to perform signal processing according to a second communication standard. Furthermore, the multi-standard transceiver includes an interference cancellation unit configured to drive an estimated interference signal from a first signal generated by the first subunit by performing the signal processing according to the first communication standard, and perform interference cancellation on a second signal generated by the second subunit by performing the signal processing according to the second communication standard based on the estimated interference signal.

FIELD

Embodiments of the present invention create a multi-standard transceiver for processing signals according to different communication standards, for example, to be used in wired or wireless communication systems. Further embodiments create devices performing interference cancellation.

BACKGROUND

Modern System-on-Chip (SoC) devices for mobile phone applications support various radio-standards like GSM, Bluetooth, FM radio.

Crosstalk can appear when two standards are operated in parallel. The harmonics of the transmit signal of standard A can fall into the receive band of standard B and can reduce the sensitivity of receive path B.

For example, the 9th harmonic of a 104 MHz FM radio transmit signal couples via the FMR-antenna to the GSM-antenna and falls into the receive band of the GSM 900 standard and reduces the sensitivity of a GSM receive signal located at 936 MHz.

SUMMARY

Embodiments of the present invention create a multi-standard transceiver comprising a first subunit configured to perform signal processing according to a first communication standard and a second subunit configured to perform signal processing according to a second communication standard. Furthermore, the multi-standard transceiver comprises an interference cancellation unit configured to derive an estimated interference signal from the first signal generated by the first subunit by performing the signal processing according to the first communication standard. Furthermore, the interference cancellation unit is configured to perform interference cancellation on a second signal generated by the second subunit by performing the signal processing according to the second communication standard based on the estimated interference signal.

Further embodiments of the present invention create a device comprising a first subunit configured to transmit a first communication signal at a transmit frequency and a second subunit configured to receive a second communication signal at a receive frequency. The first subunit and the second subunit are configured such that a relationship between the transmit frequency and the receive frequency varies. Furthermore, the device comprises an interference cancellation unit configured to survey the relationship (between the transmit frequency and the receive frequency) and activate an interference cancellation if the relationship fulfills a predetermined condition.

Further embodiments of the present invention create a device comprising a first transceiver subunit, a second transceiver subunit and an interference cancellation unit coupled between the first transceiver subunit and the second transceiver subunit.

Further embodiments of the present invention create a device comprising a plurality of subunits, each of the subunits being configured to perform signal processing. Furthermore, the device comprises a control unit configured to selectively activate and deactivate each of the subunits and to activate an interference cancellation, if a combination of active subunits fulfills a predetermined condition.

DETAILED DESCRIPTION

Before embodiments will be described in detail using the accompanying figures, it is to be pointed out that the same or functionally equal elements will be provided with the same reference numbers and that a repeated description of elements provided with the same reference numbers is omitted. Hence, descriptions of elements provided with the same reference numbers are mutually exchangeable.

FIG. 1shows a block schematic diagram of a multi-standard transceiver100according to an embodiment.

The multi-standard transceiver100comprises a first subunit101configured to perform signal processing according to a first communication standard and a second subunit103configured to perform signal processing according to a second communication standard.

Furthermore, the multi-standard transceiver100comprises an interference cancellation unit105configured to derive an estimated interference signal107from a first signal109generated by the first subunit101by performing the signal processing according to the first communication standard. Furthermore, the interference cancellation unit105is configured to perform interference cancellation on a second signal111generated by the second subunit103by performing the signal processing according to the second communication standard based on the estimated interference signal107.

It has been found that signal processing according to a first communication standard can influence a simultaneous or concurrent signal processing according to a second communication standard. As an example, the signal processing according to the first communication standard may generate the first signal109which may influence the second signal111generated by the signal processing according to the second communication standard. As an example, a frequency or a harmonic of the first signal109may fall into a passband for the second signal111and therefore may influence the second signal111. In the case of the second signal111being a receive signal, the first signal109may influence the second signal111such that a sensitivity for the second signal111in the second subunit103is decreased. By performing the interference cancellation using the interference cancellation unit105the influence of the first signal109on the second signal111can be reduced or even canceled.

Furthermore, the second signal111may be a transmit signal according to the second communication standard, which is to be sent by the multi-standard transceiver100and onto which the first signal109or a harmonic of the first signal109would be superpositioned without the interference cancellation performed by the interference cancellation unit105and therefore would reduce the signal quality of the transmit signal. Although in embodiments the superposition between the first signal109or its harmonics and the second signal111may occur, countermeasures are taken by the interference cancellation unit by performing the interference cancellation using the estimated interference signal107based on the first signal109, such that the effect of the superposition can be reduced or even canceled.

The first signal109, for example, may be a transmit signal according to the first communication standard, which is to be transmitted by the multi-standard transceiver100. Furthermore, the first signal109may be a baseband signal based on which the interference cancellation unit105derives the estimated interference cancellation signal107. It is not necessary that the first signal109itself influences the second signal111, for example, the first signal109in the baseband may get upmixed to a transmit frequency of the first communication standard and this transmit frequency or a harmonic of this transmit frequency may fall in a passband for the second communication standard. Nevertheless, the interference cancellation can be performed (based on the first signal109) using the interference cancellation unit105in the baseband, which needs a much lower effort than performing the interference cancellation at the high signal transmission frequencies.

Furthermore, the first signal109may be an internal signal used in the first subunit for performing the signal processing according to the first communication standard, for example, a clock signal generated or used by an oscillator (for example, by a digitally controlled oscillator (DCO) or a PLL (phase locked loop)) or a synthesizer signal, which is used to upmix a baseband signal to a transmit frequency or for downmixing a communication signal from a received frequency to the baseband. A frequency or a harmonic of the synthesizer signal may fall into a passband of the second communication standard, for example, the synthesizer frequency or a harmonic of it may be equal or similar to a synthesizer frequency used in the second communication standard, such that the signal processing according to the first communication standard may influence the signal processing according to the second communication standard. Therefore, the interference cancellation unit105may derive the estimated interference signal107from different types of signals generated in the first subunit101by the signal processing according to the first communication standard, which may influence the signal processing according to the second communication standard.

Compared to a receive signal the first signal109is typically known in the system, such that the interference cancellation unit105can derive the estimated interference signal107based on the known first signal109.

According to further embodiments, the multi-standard transceiver100may comprise a control unit110which is configured to activate and deactivate the interference cancellation unit105. The control unit110may activate the interference cancellation unit105if a crosstalk condition between the signal processing according to the first communication standard and the signal processing according to the second communication standard is fulfilled. As an example, the control unit110may activate the interference cancellation unit105if a frequency of a signal generated by the signal processing according to the first communication standard or a harmonic of this frequency is equal to or similar to a frequency of a signal used in the second subunit by performing the signal processing according to the second communication standard.

As an example, if frequencies of signals generated by performing the signal processing according to the first communication standard or harmonics of these frequencies are not similar or equal to frequencies of signals generated in the second subunit by performing the signal processing according to the second communication standard, the control unit110may deactivate the interference cancellation unit105.

Furthermore, the control unit110may be configured to selectively activate and deactivate the first subunit101and the second unit103and to activate the interference cancellation unit105if the first subunit101and the second subunit103are activated concurrently. In other words, the multi-standard transceiver may perform the signal processing according to the first communication standard and the signal processing according to the second communication standard independent from each other. The control unit110may only activate the interference cancellation105if both subunits101,103are activated simultaneously, for example, because the signal processing according to the first communication standard influences the signal processing according to the second communication standard.

In general, the first communication standard and the second communication standard may be wired or wireless communication standards. Furthermore, one of the communication standards may be a wired communication standard, while the other communication standard is a wireless communication standard. The two communication standards, for example, may differ in communication protocols used, modulation schemes, data rates, signal output power, signal input power, transmit frequencies, or reception frequencies.

For example, the communication standards may be chosen from a group consisting of:

DSL (digital subscriber line), Ethernet, Bluetooth, WLAN (wireless local area network), GSM (global standard for mobile communication), UMTS (universal mobile telecommunication system), LTE (long-term evolution), DVB (digital video broadcasting), DAB (digital audio broadcasting), FM radio (FM—frequency modulation), AM radio (AM—amplitude modulation). The first and the second communication standard may be different from each other.

FIG. 2shows a block schematic diagram of a multi-standard transceiver200as a possible implementation of the multi-standard transceiver100as a further embodiment.

The abbreviations used inFIG. 2represent different signals, as follows:

Wanted transmit signal A in baseband and RF domain:
sTX—A,sTX—A—RF;
Unwanted nthharmonic of transmit signal A in RF domain:
snTX—A—RF;
Overall transmit signal A in RF domain:
sTX—A—RF+snTX—A—R;
Echoed nthharmonic of transmit signal A within frequency band B in RF and baseband domain:
echo—snTX—A—RF,echo—snTX—A;
Nthharmonic of wanted transmit signal A in baseband:
snTX—A;
Frequency shifted nthharmonic of wanted transmit signal A: snTX—A—Δf=snTX—A·cos(2πΔft)
whereas Δf is defined as:
Δf=n·fTX—A−fTX—B;
Estimated echo signal:
e′·snTX—A—Δf;
Wanted receive signal B in RF and baseband domain:
sRX—B—RF,sRX—B;
Overall receive signal in baseband domain:
s′RX—B=sRX—B+echo—snTX—A;
Receive signal after echo cancellation:
s″RX—B=s′RX—B−e′·snTX—A—Δf;
Receive signal after filtering:
s′″RX—B=FIL(s″RX—B).

The multi-standard transceiver200comprises the first subunit101(also designated as subunit A), the second subunit103(also designated as subunit B), the control unit110(also designated as control unit C), and the interference cancellation unit105(also designated as echo cancellation unit E).

The first subunit101is configured to perform signal processing according to a first communication standard, the second subunit103is configured to perform signal processing according to a second communication standard.

In the first subunit101the first signal109is generated by performing the signal processing according to the first communication standard and in the second subunit103the second signal111is generated by performing the signal processing according to the second communication standard.

The second subunit103generates the second signal111in the baseband by downmixing a second communication signal111′ with a receive frequency fRX—Bof the second communication standard. The second communication signal111′ comprises the wanted receive signal sRX—B—RFand the echoed nthharmonic of the first communication signal109′ echo_snTX—A—RFin the RF domain.

In the example inFIG. 2the first signal109is a wanted transmit signal in the baseband (also designated as sTX—A). The second signal111is, in the example shown inFIG. 2, a wanted receive signal in the baseband domain (also designated as s′RX—B).

As part of the signal processing according to the first communication standard the first subunit101transforms the first signal109from the baseband to a first communication signal109′ in the RF domain. The first subunit101derives the first communication signal109′ by upmixing the first signal109based on a transmit frequency fTX—A(also designated as frequency of the transmit signal of the first communication standard) of the first communication standard. Due to the upmixing of the first signal109to the first communication signal109′, harmonics of the first signal109are generated, which are superpositioned on the first communication signal109′. An unwanted nthharmonic of the wanted transmit signal109in the RF domain is designated as snTX—A—RF.

Crosstalk appears if the harmonic of the transmit signal (generated by upmixing the first signal109to the first communication signal109′) of the first subunit101falls into the receive band of the second communication standard. As an example, the crosstalk condition can be described by the following formula;
n·fTX—A≈fRX—B,  (1)

wherein fTX—Adenotes the frequency of the transmit signal of the first communication standard, fRX—Bdenotes the frequency of the transmit signal of the second communication standard and n is a factor to denote the nthharmonic of the transmit signal of the first communication standard.

The control unit110, which, for example, may be a microprocessor unit, can check whether the condition above is fulfilled while or before the first communication standard transmits or the second communication standard receives. If the crosstalk condition is fulfilled, the control unit110or the microprocessor111activates the interference cancellation unit105(also designated as interferer cancellation unit).

The interference cancellation unit105estimates the interference portion or the echo portion213(also designated as echo_snTX—A—RF) of the first communication signal109′ in the receive band of the second communication standard. Based on this estimation the interference cancellation unit105derives the estimated interference signal107(also designated as estimated echo signal e′·snTX—A—Δf). The estimated interference signal107is subtracted from the overall receive signal. For example, the estimated interference signal107is subtracted from the second signal111(also designated as overall receive signal s′RX—Bin the baseband).

The second signal111or the overall receive signal in the baseband equals:
s′RX—B=sRX—B+echo—snTX—A.  (2)

In other words, the overall receive signal in the baseband domain comprises the wanted receive signal sRX—Band the echoed nthharmonic of the first communication signal109′ transferred to the baseband domain.

As mentioned before, the second communication signal111′ comprises the wanted receive signal in the RF domain sRX—B—RFand the echoed nthharmonic echo_snTX—A—RFof the first communication signal109′ in the RF domain.

This first communication signal111′ including the echoed harmonic of the first communication signal109′ is downmixed to the first signal111from which the estimated interference signal107is subtracted to derive an interference free receive signal111″ (also designated as receive signal after echo cancellation s″RX—B).

In other words the interference free receive signal111″ can be derived as the following:
s″RX—B=s′RX—B−e′·snTX—A—Δf.  (3)

According to further embodiments, in cases, in which the interference cancellation is performed on transmit signals, an interference free transmit signal may be generated. In general, an interference free signal is generated.

As the interference signal107is only estimated, the interference free receive signal111″ may be not completely interference free but the interference may be at least reduced by a large amount, for example by 50%, 80%, 90% or 99%.

The control unit110activates the interference cancellation unit105if a crosstalk condition between the signal processing according to the first communication standard and the signal processing according to the second communication standard is fulfilled.

As an example, the crosstalk condition may be:
|n·(fTX—A+/−0.5·fBW—A)−fRX—B|≦0.5·fBW—B(4)
in which
fBW—Adesignates the bandwidth of a passband filter for the first communication standard (for example for a transmit path of the first communication standard) and fBW—Bdenotes a bandwidth of a passband filter of the second communication standard (for example of a receive path of the second communication standard). Therefore, the control unit110may activate the interference cancellation unit105if the first communication signal109′ derived from the first signal109or a harmonic (for example the nthharmonic) of the first communication signal109′ falls into the passband for the second communication signal111′ based on which the second subunit103generates the second signal111.

The first communication signal109′ and the second communication signal111′ may be independent from each other, in other words the first subunit101may be configured to perform the signal processing according to the first communication standard independently from the signal processing according to the second communication standard of the second subunit103. Vice versa the second subunit103may be configured to perform its signal processing independently from the signal processing of the first subunit101. As an example, the multi-standard transceiver200may be configured to communicate according to the first communication standard using the first subunit101and simultaneously or concurrently communicate according to the second communication standard using the second subunit103.

According to further embodiments, for example, a frequency generated in the first subunit101may be continuously generated, when the first subunit101is activated and may not (or only slightly) vary over time (e.g. a constant clock signal, from an oscillator). The frequency or a harmonic of this frequency may fall into the passband of the second subunit103, in this case the control unit110may activate interference cancellation unit105(only) if the first subunit and the second subunit are activated concurrently.

Furthermore, as the multi-standard transceiver200may not need to communicate always using both the first subunit101and the second subunit103, the control unit110may be configured to selectively activate and deactivate the first subunit101and the second subunit103and may activate the interference cancellation unit105if the first subunit101and the second subunit103are activated concurrently.

According to further embodiments the first subunit101may comprise a first frequency synthesizer215to generate a first frequency synthesizer signal having the first synthesizer frequency fTX—A, based on which the subunit101performs the signal processing according to the first communication standard. In the example shown inFIG. 2, the first subunit101upmixes the first signal109to the communication signal109′ using the first synthesizer signal with the first synthesizer frequency fTX—Aas part of the signal processing according to the first communication standard. The first synthesizer frequency fTX—Acan be defined by the first communication standard, wherein one communication standard may have different synthesizer frequencies, for example, for different channels. As an example, the UMTS standard has several UMTS bands, each having its own transmit synthesizer frequency and receive synthesizer frequency. As a further example, if the first communication standard is an FM radio standard, then the first synthesizer frequency fTX—Acan be changed depending on the frequency at which the first signal109has to be transmitted.

Furthermore, the second subunit103may comprise a second frequency synthesizer217configured to generate a second synthesizer signal having the second synthesizer frequency fRX—B, based on which the second subunit103performs the signal processing according to the second communication standard. As with the first communication standard and the first subunit101, the second synthesizer frequency fRX—Bmay change depending on a channel or band of the second communication standard used in the second subunit103.

As the first synthesizer frequency fTX—Aand the second synthesizer frequency fRX—Bmay change, the control unit110may be configured to survey a relationship between the first synthesizer frequency fTX—Aand the second synthesizer frequency fRX—Band to activate the interference cancellation unit105(only) if the a predetermined condition for the relationship is fulfilled.

As mentioned before, equation 1 shows an example for such a predetermined condition.

As described before, the first subunit101may be independent from the second subunit103. Therefore, the multi-standard transceiver200may perform a first communication according to the first communication standard with a first external device using the first subunit101and simultaneously perform a second communication according to the second communication standard with a second external device using the second subunit103.

To give an example, the first communication standard may be an FM radio standard and the second communication standard may be a mobile communication standard, such as UMTS or GSM.

The multi-standard transmitter may transmit data to an FM radio and simultaneously receive data, for example, from a mobile communication base station. As can be seen, performing a communication does not necessarily mean that data has to be transmitted and received, a communication may also be a one-way communication, for example, only receiving data or only transmitting data.

According to further embodiments the first subunit101not only may be configured to generate the first communication signal109′, but also to transmit the first communication signal109′ at the transmit frequency fTX—Aof the first communication standard. Furthermore, the second subunit103may be configured to generate by reception and amplification the second communication signal111′ at the receive frequency fRX—Bof the second communication standard.

In one embodiment the interference cancellation unit105may derive the estimated interference signal107such that it describes the echo portion echo_snTX—A—RF(e.g. falling into the passband of the second communication signal111′) of the first communication signal109′ within the second communication signal111′.

Furthermore, as already mentioned before, the interference cancellation unit105may be configured to subtract the estimated interference signal107from the second signal111in the baseband, to derive the interference free receive signal111″.

The transmit signal of the first communication standard in the RF domain (the first communication signal109′) can be split into the wanted signal portion sTX—A—RFand the unwanted nthharmonic signal portion snTX—A—RF. The receive signal (the second communication signal111′) in the RE band of the second communication standard comprises the wanted receive signal sRX—B—RFand the echo of the nthharmonic of the transmit signal or the first communication signal109′ called echo_snTX—A—RF. It is assumed that the echo of the wanted signal sTX—A—RFdoes not fall into the frequency band of the second communication standard. In this example, this echo portion can be ignored.

The echo cancellation unit E or the interference cancellation unit105estimates the echo portion of the transmit signal via correlation (in the baseband) of the received signal s″RX—B(the interference free receive signal111″) with the frequency shifted nthharmonic of the wanted transmit signal sTX—A. The estimated echo within the frequency band of the second communication standard is subtracted from the overall receive signal s′RX—B(the second signal111).

In case of an ideal echo cancellation and after attenuation of unwanted out of band components, for example using a filter219of the first subunit103, a signal s′″RX—Bonly contains the wanted portion of the receive signal sRX—B.

In other words, interference cancellation unit105may be configured to derive an echo transfer function e′ (also designated as echo coefficient e′) describing a coupling between the first communication signal109′ transmitted by the first subunit101and the second communication signal111′ received by the second subunit103. The interference cancellation unit105may update the echo transfer function e′ in response to changes of the coupling between the first communication signal109′ and the second communication signal111′ and may derive the estimated interference signal107based on the echo transfer function e′. As an example, a transmission characteristic or a propagation path between the first subunit101and the second subunit103may change and therefore the echo portion213of the first communication signal109′ in the second communication signal111′ may change and the interference cancellation unit105may adapt the echo transfer function e′ in response to such a change of the echo portion213based on the correlation between the interference free receive signal111″ and a frequency shifted harmonic snTX—A—Δfof the communication signal109′ in the baseband.

In other words, the interference cancellation unit105may be configured to derive an nthharmonic of the first communication signal109′ in the baseband, the nthharmonic of the first communication signal109′ falling into the passband for the second communication signal111′. The interference cancellation unit105may derive the estimated interference signal107by combining (in the baseband) the echo coefficient or the echo transfer function e′ and the nthharmonic snTX—A—Δfof the first communication signal109′ in the baseband. According to an embodiment the interference cancellation unit105may fold the echo transfer function e′ and the nthharmonic snTX—A—Δfof the first communication signal109′ in the baseband to derive the estimated interference signal107.

Furthermore, the interference cancellation unit105may be configured to derive the echo coefficient or the echo transfer function e′ by calculating (in the baseband) a correlation based on the nthharmonic snTX—Aof the first communication signal109′ in the baseband and on the interference free receive signal111″ in the baseband. By performing the correlation in the baseband, instead of performing the correlation in the RF domain, a calculation effort can be dramatically reduced.

Furthermore, the interference cancellation unit105may be configured to frequency shift the nthharmonic snTX—A(in the baseband) based on a difference between n times the transmit frequency fTX—Aand the receive frequency fRX—B. In other words:
Δf=n·fTX—A−fTX—B.  (5)

Accordingly, the frequency shifted nthharmonic of the wanted transmit signal A (of the first signal109) is defined as:
snTX—A—Δf=snTX—A·cos(2πΔft).  (6)

The frequency shifted nthharmonic snTX—A—Δfdescribes the harmonic SnTX—A—RFwithin the first communication signal109′ in the RF domain.

According to further embodiments, the first subunit101may comprise a transmit filter, a passband of which is adapted to a transmit frequency band of the first communication standard and a receive filter, a passband of which is adapted to a receive frequency band of the first communication standard. The transmit frequency band of the first communication standard may be different from the receive frequency of the second communication standard.

Furthermore, the second subunit103may comprise a transmit filter, a passband of which is adapted to a transmit frequency of the second communication standard and a receive filter, a passband of which is adapted to a receive frequency of the second communication standard.

The transmit frequency of the second communication standard may be different from the receive frequency of the second communication standard.

Furthermore, the first subunit101may be configured to generate the first communication signal109′, wherein the maximum amplification for the first communication100′ is chosen such that a maximum power of a first communication signal109′ is equal or below an upper limit for the power defined by the first communication standard.

Furthermore, the second subunit103may be configured to generate the communication signal sTX—B—RFaccording to the second communication standard and a maximum amplification for this communication signal sTX—B—RF(for example as a transmit signal) may be chosen such that a maximum power of this communication signal sTX—B—RFis equal to or below an upper limit for the power defined by the second communication standard.

As an example the first communication standard may be a Bluetooth standard and the second communication standard may be a GSM standard. A maximum output power for the Bluetooth standard is typically lower than a maximum output power for the GSM standard. Therefore, in a transmit path of the first subunit101a lower amplification is performed than in a transmit path of the second subunit103.

In other words, an upper limit for the power defined by the first communication standard may be different from the upper limit for the power defined by the second communication standard.

According to further embodiments the first communication standard may be a first RF (radio frequency) communication standard and the second communication standard may be a second RF communication standard.

The multi-standard transceiver200may be configured to communicate simultaneously using the first RF communication standard and the second RF communication standard.

Furthermore, the first subunit101may be configured to transmit and receive signals. Furthermore, the second subunit103may be configured to transmit and receive signals.

Typically, a transfer characteristic or a propagation path between the first subunit101and the second subunit103changes slowly. Therefore, according to further embodiments, the calculation of a change of the echo coefficient or the echo transfer function e′ can be performed by averaging the instantaneous correlation between the frequency shifted nthharmonic snTX—A—Δfand the receive signals111″. According to some embodiments the echo coefficient or the echo transfer function e′ may be a filter.

To summarize, the multi-standard transceiver200comprises the control unit110(for example a microprocessor) and the subunits A, B for the various communication standards A and B, for example for various mobile phone standards A and B.

The example inFIG. 2has the advantage of a low current consumption and a low bill of material, due to no needed external components. The interferer signal (the estimated interference signal107) can be estimated and subtracted in the baseband frequency domain, i.e. the data rate of the interference cancellation unit105is low.

The control unit110checks whether the harmonics of the transmit signal of the subunit A (the first subunit101) fall into the receive band of the subunit B (the second subunit103).

If the crosstalk condition is fulfilled, the interference cancellation unit105estimates the interferer portion of the transmit signal A within the receive band of the second subunit103. The estimated interferer signal (the estimated interference signal107) is subtracted from the overall receive signal111′ of the second subunit103.

Harmonics of the transmit signal do not appear anymore in the receive part of the second subunit103.

The multi-standard transceiver200may be applied for both wireless applications (for example like mobile phone applications) and wire line applications.

In the example shown inFIG. 2the transmit frequency fTX—Aof the first subunit101and the receive frequency fRX—Bof the second subunit103are sent to the control unit or microprocessor unit111. If the crosstalk condition is fulfilled, i.e. the nthharmonic of the transmit signal A (of the first communication signal109′) falls into the receive band of the second communication standard, the echo cancellation unit or the interference cancellation105is activated.

The multi-standard transceiver200can be used for both multi-standard mobile phone and multi-standard wire line communication systems. Furthermore, deterministic spurs or harmonic carrier signals can also be cancelled following the approach described in conjunction withFIG. 2. In other words, embodiments enable the cancellation of deterministic spurs or harmonic carrier signals.

In the following, additional embodiments will be described in short, covering additional aspects.

There may be cases in which a first subunit may transmit a communication signal and a second subunit may receive a communication signal, and the first subunit or the second subunit may generate an interference in the other subunit, independent of the communication standards used by the subunits. Hence, an interference cancellation can also be advantageous in cases in which an interference occurs independent from different communication standards.

The device300comprises a first subunit301configured to transmit a first communication signal109′ at a transmit frequency fTX—A. Furthermore, the device300comprises a second subunit303configured to receive a second communication signal111′ at a receive frequency fRX—B.

Furthermore, the device300comprises an interference cancellation unit305.

The interference cancellation unit305is configured to survey a relationship between the transmit frequency and the receive frequency and to activate interference cancellation if the relationship fulfills a predetermined condition. As an example, the predetermined condition may be equal to equation 4 mentioned above.

According to further embodiments, the first subunit301and the second subunit303may be configured such that a relationship between the transmit frequency fTX—Aand the receive frequency fRX—Bvaries.

Of course, the first communication signal109′ and the second communication signal111′ may be from different communication standards, but may also be from the same communication standard. As an example, the first subunit301may transmit the first communication signal109′ in a first UMTS band and the second subunit303may receive the second communication signal111′ in a second UMTS communication band. The transmit frequency fTX—Aof the first UMTS band may fall into a receive passband for the second communication signal111′ defined by a standard for the second UMTS band used in the subunit303.

Furthermore, as an example for two different communication standards, the first communication signal109′ may be an FM radio transmit signal with a transmit frequency fTX—Aof 104 MHz and the second communication signal111′ may be a GSM receive signal with a receive frequency of fRX—Bof 936 MHz. In this case, the 9thharmonic of the first communication signal109′ would couple via an FM radio antenna to an GSM antenna and reduce the sensitivity of the second communication signal111′. Hence, the first subunit301may be configured according to a first communication standard and the second subunit303may be configured according to a second communication standard.

In both cases mentioned above the interference cancellation unit detects that the relationship fulfills the predetermined condition and may activate the interference cancellation.

Furthermore, the device300may comprise additional features like it has been described in conjunction with the multi-standard transceiver200according toFIG. 2. In other words, the features described in conjunction with the multi-standard transceiver200may be applicable to the device300as well.

Furthermore, there may be devices comprising two or more subunits, each subunit being configured to transmit and receive a communication signal.

FIG. 4shows such an example with a device400comprising a first transceiver subunit401and a second transceiver subunit403. Furthermore, the device400comprises an interference cancellation unit405coupled between the first transceiver subunit401and the second transceiver subunit403. The interference cancellation unit405may be configured to perform an interference cancellation between the first transceiver subunit401and the second transceiver subunit403, for example, in both directions, i.e. the interference cancellation unit405may reduce an interference generated by the second transceiver subunit403in the first transceiver subunit401and an interference generated by the first transceiver subunit401in the second transceiver subunit403.

Furthermore, the device400may comprise additional features, for example features described in conjunction with the multi-standard transceiver200. In other words, the features described in conjunction with the multi-standard transceiver200may be applicable to the device400as well.

Furthermore, there may be cases in which a signal processing from one subunit interferes with a signal processing of a second subunit (always or only) when both of the subunits are activated.

For this case,FIG. 5shows a device500comprising a plurality of subunits501,503. Each of the subunits is configured to perform signal processing.

Furthermore, the device500comprises an interference cancellation unit505coupled between the plurality of subunits501,503and a control unit510to selectively activate and deactivate each of the subunits501,503and to activate the interference cancellation unit505, if a combination of active subunits fulfills a predetermined condition.

As an example, the control unit510may activate the interference cancellation unit505if the first active subunit performs a signal processing, which interferes with the signal processing of a second active subunit. Furthermore, the device500may comprise subunits which can be active simultaneously and wherein no interference appears, such that the control unit510may not activate the interference cancellation unit505if these subunits are active.

Although, in the example ofFIG. 5only two subunits are shown, according to further embodiments, the device500may comprise an arbitrary number of subunits.

The device500may comprise additional features, for example, features which have been described in conjunction with the multi-standard transceiver200. In other words, the features described in conjunction with the multi-standard transceiver200may be applicable to the device500too

FIG. 6shows a flow diagram of a method600according to an embodiment.

The method600comprises a step601of performing signal processing according to a first communication standard.

Furthermore, the method600comprises a step603of performing signal processing according to a second communication standard.

Furthermore, the method600comprises a step605of deriving an estimated interference signal from a first signal generated by the signal processing according to the first communication standard.

Furthermore, the method600comprises a step607of performing interference cancellation on a second signal generated by the signal processing according to the second communication standard based on the estimated interference signal.

The method600may be performed by the multi-standard transceiver100or the multi-standard transceiver200. Furthermore, the steps of the method600may be performed simultaneously or concurrently, such that the interference cancellation is performed during the signal processing according to the first communication standard and the signal processing according to the second communication standard.

FIG. 7shows a flow diagram of a method700according to a further embodiment of the present invention.

The method700comprises a step701of transmitting a first communication signal at a transmit frequency.

Furthermore, the method700comprises a step703of receiving a second communication signal at a receive frequency.

Furthermore, the method700may comprise an optional step705of varying a relationship between the transmit frequency and the receive frequency.

Furthermore, the method700comprises a step707of surveying the relationship between the transmit frequency and the receive frequency, and activating an interference cancellation if the relationship fulfills a predetermined condition.

The method700may be performed by the device400. Furthermore, the steps of the method700may be performed simultaneously or concurrently, such that the interference cancellation is activated during the transmission of the first communication signal and reception of the second communication signal, simultaneously.

Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable non-transitory carrier.