Transceiver and associated operating method

Abstract

A transceiver (10) comprises a receiver unit (20) and a transmitting unit (30), wherein the receiver unit (20) is designed to receive a first RF signal; wherein the transmitting unit (30) comprises an RF signal generator (34) which is designed to generate a second RF signal at a second carrier frequency (f2) on the basis of the first RF signal and signal information (I), wherein the second carrier frequency (f2) differs from a first carrier frequency (f1).

Description

[0001] Transceiver and associated operating procedure

[0002] Description

[0003] Embodiments of the present invention relate to a transceiver, as well as an associated operating method and a computer program. Preferred embodiments of the invention provide a device for battery-free and wireless reception and transmission of radio messages without a quartz crystal, e.g., for 3GPP or IEEE.

[0004] To transmit data wirelessly, a transmitting device requires a precise clock to generate a signal with the correct transmission frequency. In conventional communication systems, the clock is typically generated using an oscillator. However, oscillators suitable for generating the required high-frequency signal are too power-hungry for many applications (e.g., passive IoT devices, Internet of Things devices). Therefore, there is a need for an improved approach.

[0005] The object of the present invention is to provide a reference signal, in particular for a radio receiver (transceiver), which is characterized by high energy efficiency.

[0006] The problem is solved by the subject matter of the independent patent claims.

[0007] Embodiments of the present invention provide a transceiver with a receiver unit and a transmitter unit. The receiver unit is configured to receive a first RF signal having a first carrier frequency. The transmitter unit comprises an RF signal generator configured to generate a second RF signal having a second carrier frequency based on the first carrier frequency or a frequency modulated onto the first RF signal, as well as signal information (contained in or extracted from the first RF signal, another RF signal, or from a modulation of the first RF signal). The second carrier frequency is different from the first carrier frequency.

[0008] Embodiments of the present invention are based on the finding that a received high-frequency reference signal with carrier frequency / receive frequency fi can reliably generate a frequency f2 that differs from it if additional information is available. This additional information is provided by additional signaling (or another signal property, such as a subcarrier or modulation) in the reference signal. In other words, the additional signaling advantageously enables the generation of a frequency that differs from fi, or a decoupled frequency f2, which can be used as a carrier frequency.

[0009] The system allows for significant simplification of the communication devices used to read passive nodes. Based on exemplary embodiments, mobile phones, for example, can be used for reading. This opens up a new market with extensive application possibilities for passive IoT devices, which differ from conventional backscattering systems (UHF RFID) in the following ways: Depending on the system design, either significantly improved data transmission performance is possible (longer range or data rate) or the same performance with a significantly weaker required carrier signal. The advantage over devices with their own oscillator is that, according to exemplary embodiments, the devices require significantly less energy to communicate. This enables passive devices that can be operated by energy harvesting.

[0010] According to embodiments, the RF signal generator is designed to determine the first carrier frequency or the modulated frequency or a reference dependent on the first carrier frequency or the modulated frequency.

[0011] Furthermore, according to embodiments, the signal generator is configured to generate the second carrier frequency as a function of the first carrier frequency by frequency dividing, modulating, or frequency shifting the first carrier frequency, or by supplementing the first RF signal. The signal information may include a multiplier or divider on the first carrier frequency or on the modulated frequency. According to one embodiment, the RF signal generator may be configured to generate the second RF signal with a frequency hopping pattern with at least two second carrier frequencies, defined by the signal information.

[0012] A further embodiment provides a transceiver in which means for providing energy are provided. Examples of this are RF-to-DC energy harvesting means designed to harvest electrical energy, in particular a direct voltage, from a radio field or the radio field associated with the first RF signal. For this purpose, one or more antennas with a matching network that performs a frequency variation can be used. According to further embodiments, the energy harvesting means are designed to harvest electrical energy from another energy form, e.g., light radiation or ambient temperature. According to a further embodiment, the energy harvesting means alternatively or additionally comprise an energy store designed to store electrical energy. This can be a battery or a simple capacitor.

[0013] Regarding the first carrier frequency, it should be noted that, according to embodiments, it can be in the sub-1 GHz frequency range or sub-5 GHz frequency range, or even a carrier frequency with a center frequency in a spectrum defined by IEEE 802.11 b / g / n / ac bands. The second transmission frequency can, according to embodiments, be in a 2.4 GHz frequency range (generally sub-5 GHz or sub-10 GHz) or generally in a frequency range specified by IEEE 802.11 b / ba. It should be noted that the approach can also be implemented in any other frequency band if f1 and f2 are different.

[0014] From now on, the two standards will be referred to as IEEE 802.11b and IEEE 802.11ba. This is not a typo. IEEE 802.11b is actually a fairly old standard for data transmission. IEEE 802.11ba is a new standard that specifies low-power transmission for low-power receivers (so-called wake-up receivers).

[0015] According to embodiments, the second carrier frequency is generated based on the first carrier frequency when the first RF signal is initially present / only initially present. Alternatively, a first RF signal can also be continuously present, in which case, for example, this also continuously serves to generate the second RF signal. According to embodiments, the first RF signal is only initially present, only after a jump, or continuously present. The evaluation is therefore performed only initially, after a jump, or continuously by the receiver unit.

[0016] According to embodiments, a data packet is modulated onto the first RF signal. This can, for example, carry the signal information for generating the second RF signal. Possible modulation methods are BPSK, GFSK, 2-ASK, and / or OOK. According to embodiments, the transceiver further comprises a modulator configured to modulate data packets onto the second carrier frequency, e.g., using BPSK, GFSK, 2-ASK, and / or OOK. According to embodiments, the transceiver or the receiver unit of the transceiver comprises one or more of the following elements:

[0017] - Preamplifier

[0018] - Demodulator

[0019] - Quantizer, especially ADC comparator

[0020] - Counter

[0021] According to embodiments, the quantizer is designed to use a threshold value to output discrete signals based thereon for determining the first carrier frequency. According to embodiments, the counter can, for example, be arranged downstream of the quantizer and can be designed to determine the first carrier frequency by counting the number of oscillations between two timestamps in the first RF signal (e.g., between two main carriers) in one or more sections of the RF signal and / or to determine at least one channel spacing of the first carrier frequency. Regarding the counter explained above, it should be noted that it is designed to determine the carrier frequency in a main carrier or a subcarrier. The carrier frequency can also be derived from an offset between a main carrier and a subcarrier.

[0022] According to embodiments, the demodulator is configured to provide a voltage or current signal that correlates with an RF carrier amplitude. Additionally or alternatively, the demodulator may include an OOK envelope detector. According to embodiments, the demodulator is connected upstream of the comparator or quantizer and provides an AM signal demodulated from the carrier frequency.

[0023] The above-explained elements, quantizer, counter, and demodulator, are part of the receiver path according to a preferred embodiment and serve to determine the first carrier frequency. After detection, this carrier frequency is transferred to the transmitter path (transmitting unit), so that the latter determines the second carrier frequency depending on the first carrier frequency. According to embodiments, PLL Divider_N, RFID Divider_R, and Look-Up Table can be used here. According to embodiments, the transmitting unit has a frequency divider that is designed to derive frequency division values ​​Div_R from an internal reference derived from the first carrier frequency or from the first carrier frequency itself. According to further embodiments, the transmitting unit has a look-up table, e.g.on the input side of the frequency divider, which is designed to provide a square wave signal based on the first carrier frequency or on an internal reference derived from the first carrier frequency. According to embodiments, the frequency divider is implemented as an integer-N PLL synthesizer and / or comprises a frequency-locked loop (FLL). A further divider can be present additionally or alternatively. According to embodiments, the three mentioned implementation variants or at least one of the three mentioned implementation variants is designed to determine the second irradiation frequency based on the first carrier frequency or an internal reference derived from the first carrier frequency or to determine the second carrier frequency f2 based on the first carrier frequency f1 using the formula f2 = f1 / Div_R * Div_N.For example, Div_R represents a frequency sub-value, while Div_N is determined based on the internal reference / using a frequency hopping pattern.

[0024] According to embodiments, the transceiver can comprise multiple antennas on both the receiver and transmitter sides. This advantageously implements antenna diversity. According to embodiments, multiple receiver units can be provided for multiple RF signals with multiple first carrier frequencies. Multiple receiver frequencies in one RF signal can also be received by one or more receiver units. According to further embodiments, the transmitter unit has one or more RF signal generators configured to generate multiple second RF signals with multiple second carrier frequencies. Preferably, multiple signal generators are provided so that multiple second RF signals with second (different second) carrier frequencies can be generated.At this point, it should be noted that payload data can be transmitted via the receiver unit and received at the first and / or second carrier frequency. The transmitter unit is configured to transmit payload data at the first and / or second carrier frequency.

[0025] According to embodiments, the transceiver can receive a wake-up signal. For example, a frequency within the preamble of the RF signal can receive a wake-up signal. Furthermore, it would be conceivable, either additionally or alternatively, for the preamble to contain all the selective information and / or address information. According to embodiments, the preamble can be implemented as two-valued or multi-valued. Alternatively, the receiver unit can be configured to respond to a wake-up signal or an ID-selective, receiver-selective, or encrypted wake-up signal.

[0026] One embodiment provides a passive IoT device, such as a superheterodyne or superregenerative receiver with a transceiver as described above. According to another embodiment, a method for operating a transceiver is provided. The method comprises the steps of receiving a first RF signal having a first carrier frequency and generating a second RF signal having a second transmission frequency based on the first RF signal and signal information. The second carrier frequency is different from the first carrier frequency. According to other embodiments, the method can also be computer-implemented.

[0027] Embodiments of the present invention are explained with reference to the accompanying drawings. They show:

[0028] Fig. 1 is a schematic block diagram of a transceiver according to a basic embodiment;

[0029] Fig. 2 is a block diagram for a possible implementation of an embodiment including energy harvesting from a received signal;

[0030] Fig. 3 is a schematic block diagram of an exemplary UHF receiver with frequency determination at T according to embodiments;

[0031] Fig. 4 is a schematic block diagram of a possible implementation of a circuit block for setting the frequency divider Div_N and Div_R according to embodiments;

[0032] Fig. 5 is a schematic block diagram of a possible implementation of a radio transmitter with reference signal generator and frequency division setting according to embodiments; and

[0033] Fig. 6 shows a schematic diagram for an embedded time reference in the signal with the frequency fi. Before exemplary embodiments of the present invention are explained below with reference to the accompanying drawings, it should be noted that equivalent elements and structures are provided with the same reference numerals, so that the description of them is applicable to one another or interchangeable.

[0034] Fig. 1 shows a transceiver 10 with a receiver unit 20 and a transmitter unit 30. The receiver unit 20 is coupled, for example, by means of a receive antenna 22. The transmitter unit 30 is coupled, for example, by means of a transmit antenna 32. At this point, it should be noted that, according to exemplary embodiments, the receive antenna 22 and the transmit antenna 32 can also be combined. According to further exemplary embodiments, antenna arrays or a combined antenna array are also conceivable for both antennas. The receiver unit 20 is designed to receive an RF signal having a first carrier frequency fi. The receiver unit has, for example, a frequency determiner, e.g. implemented by a quantizer and a counter. The frequency determiner is provided with the reference numeral 24 and is designed to determine the carrier frequency fi or to output a reference signal R dependent on the carrier frequency T.

[0035] The transmitting unit has an RF signal generator 34 which is designed to generate a carrier frequency f2. This carrier frequency f2 is fed to the antenna 32 so that, for example, a signal can be modulated onto the carrier frequency f2 as a carrier frequency. The RF signal generator 34 is designed to generate the second RF signal with the second carrier frequency f2 on the basis of the first RF signal or the first carrier frequency T. f2 is different from T. For this purpose, the RF signal generator 34 also uses signal information I. This signal information is, for example, contained in the first or a further signal or extracted from the same or preconfigured. The signal information I is fed to the unit 34, e.g. as preconfigured information or as information derived from the first RF signal.

[0036] According to embodiments, only the generator 34 is required to generate the second carrier frequency, and not an oscillator or an oscillating element of an oscillator. Even without the latter, the generator 34 can precisely generate a carrier frequency from a received signal, taking into account the additional signaling information I. It should be noted at this point that the additional signaling I can also be obtained from a signal property at the reception frequency T, e.g., if it is present in the form of a subcarrier or another modulation.

[0037] Calculation example: For example, the signal information can specify a multiplier of two, so that starting from a first carrier frequency of, for example, 900 MHz, the second carrier frequency is then 1800 MHz. Alternatively to the first carrier frequency, a frequency modulated onto the first carrier frequency can be used as a basis. The multiplier can be contained as direct information in the first signal or, for example, calculated from a signal difference between a subcarrier (e.g., 902 MHz) and the main carrier of 900 MHz (difference of 2).

[0038] Avoiding oscillating elements has the advantage that precisely those energy-intensive elements are not used, thus increasing the overall energy efficiency of the transceiver 10. According to embodiments, the transceiver 10 can also be designed as a passive transceiver. For this purpose, according to embodiments, the transceiver 10 also comprises an optional energy harvester 40, which generates electrical energy, for example, from ambient energy or energy from the received signal. In this embodiment from Fig. 1, a connection is therefore provided between the energy harvester 40 and the receiving antenna 22. Both this connection and the energy harvester 40 itself are optional elements. The energy can be taken by the energy harvester 40 from a radio field of the same system or from another system (comparable to the current UHF RF-ID system).Alternatively, an implementation of an energy harvester based on another source, such as a solar cell, a thermoelectric generator, etc., would also be possible. As an alternative to the energy harvester 40, a small battery 40 can also be provided. The energy harvester 40 itself can also include means for electrical energy storage, such as a capacitor or a small accumulator.

[0039] In summary, it can be stated that by omitting precise oscillators, e.g., quartz oscillators (i.e., transceivers without a classic oscillator or quartz crystal) for generating the frequency f2, energy consumption can be minimized. The oscillator is replaced by an energy-saving oscillator or an energy-saving signal generator that generates a frequency f2 using a reference signal and additional signaling information, e.g., for calibration purposes. This allows the radio node to be operated with minimal electrical power, with the electrical energy even being able to be drawn from a radio field of another system. This allows the creation of a so-called passive IoT device.As an alternative to the harvester from a radio field (the same radio field from which fi is obtained or a different radio field), it would of course also be conceivable to use a solar cell or a thermoelectric generator for energy harvesting.

[0040] Optional aspects of the transceiver 10 are discussed below, and particular aspects of the transceiver 10 are explained in detail. According to exemplary embodiments, the transceiver 10 uses radio signals at a frequency T (preferably in the sub-1 GHz range). No components that act as frequency standards, such as quartz crystals, SAW / BAW filters, or similar, are to be used. This serves to reduce the form factor, material costs, and, above all, energy consumption. By combining the elements 20, 24, 30, and 34, the transceiver 10 independently determines the received transmission frequency fi with an adequate accuracy of, for example, 0.1 MHz and decodes incoming additional information that is, for example, modulated onto the radio signal. A frequency f2 can be generated from the received frequencies T and the additional information. The frequency T is not identical to f2.

[0041] According to an alternative implementation, the receiver 10 determines the frequency f2 based on additional reference signals on the incoming radio signal at frequency T and the additional information. In this case, the frequency T is not used as the basis for generating the frequency f2, but rather a signal component contained in the frequency T, such as a component modulated onto T. Further examples of an additional reference signal would be an additional carrier signal at an exemplary distance of 1 MHz next to the carrier signal at the frequency fi.

[0042] Using the described exemplary methods, the radio node generates the target frequency f2 to be set—preferably in the 2.4 GHz band—to which the transmitter automatically tunes. Center frequencies of the IEEE 802.11 b / g / n / ac WLAN channels should preferably be used (2407.0 MHz + n- 5.0 MHz with WLAN channel number n = 1; 2; ...; 13). The transmission frequency is set, for example, with a minimal residual deviation of less than 1.0 MHz. In a typical implementation, the frequency f2 is then used as the transmission frequency and modulated with payload data, preferably BPSK. The method is also usable for systems with a precise oscillator (e.g., quartz). For example, the oscillator could be switched off whenever a corresponding signal is available, in order to save energy in this case.

[0043] The power supply of the radio node is discussed below according to exemplary embodiments. Fig. 2 shows an exemplary implementation. Fig. 2 shows a transceiver 10' with a receiver 20, which has a downstream data decoder 25 and a control logic 26. In addition, the transceiver 10' has a transmitter path with a signal generator 34, a downstream radio transmitter 36 and an antenna driver 37, by means of which the antenna 32 is transmitted at the carrier frequency f2, onto which data to be transmitted is modulated. The data to be transmitted is fed to the radio transmitter at the target frequency 36 via the control logic 26 as a transmission frequency or modulation signal. For this purpose, the control logic receives the payload data from the data decoder 25 and the transmission data from an external unit, such as a sensor.

[0044] In addition, the transceiver 10' also includes the energy harvester 40 with the matching network 42 and RF-to-DC harvester 44 elements. The harvester 40 is also coupled to the receiving antenna 22 (like the receiver 20).

[0045] The following section discusses the functionality, particularly the operation of the energy harvester. In an advantageous implementation, the energy harvested through energy harvesting can be stored in a local energy storage device, such as a capacitor. This can be used to bridge short-term supply fluctuations. Examples include fluctuations in the power of the received wireless signal, brightness (in solar operation), or a limitation of the maximum battery current. Furthermore, the device's internal components may temporarily require higher currents than are immediately available (buffering effect of the capacitor).

[0046] In an alternative implementation, a power buffer can be omitted. In this case, the power source must be continuously available during the radio node's communication.

[0047] The harvester can optionally vary the frequency of the matching network (MNW) to use the strongest RF signal in the spectrum for RF-to-DC energy harvesting. Even if frequency hopping is used on the transmit side, the MNW must be adjusted accordingly. Pre-agreed frequency hopping schemes are used here.

[0048] Furthermore, the process can also be used for systems with conventional power supplies (normal voltage supply or battery). Here, the process can be used to save energy.

[0049] The following explains how the second carrier frequency, in particular carrier frequency f2, is generated according to exemplary embodiments. Of course, additional carrier frequencies, e.g., f1 and f4, can also be generated using the same principle with multiple transmission paths.

[0050] For clarity, only one receiver (see Figure 1) is used in the following description. However, multiple receivers, including subsequent logic / transmitters, would also be possible according to other implementation examples if additional frequencies fs, f4, etc. are required in addition to frequency f2. These chains could also be used jointly if multiple frequencies are required.

[0051] The following description contains a possible implementation of passive IoT for IEEE 802.11 (WLAN). However, this serves only as an example and can also be applied to other wireless systems.

[0052] A first WLAN device (e.g., a mobile phone) transmits a radio signal with corresponding signaling at frequency T. In an advantageous implementation, these are frequencies below 1 GHz (e.g., the frequency channels intended for UHF RFID, such as the frequency 865.7 MHz). The signal at frequency fi can also be used to supply power to the passive radio node.

[0053] Using the frequency T (or the special modulation of the signals transmitted at this frequency) and an additional signal information / data transmission (this can also be carried out at the frequency T in an advantageous approach), the passive radio node can generate a frequency f2. In an advantageous implementation, this frequency f2 lies, for example, in the 2.4 GHz frequency range used by WLAN. This has the advantage that the first WLAN device can simultaneously transmit and receive signals to the passive radio node without significant hardware complexity. This would only be possible with significant circuitry complexity when using closely spaced frequencies.

[0054] An advantageous implementation compatible with IEEE 802.11ba and IEEE 802.11b is explained below. According to exemplary embodiments, the data transmission of the necessary data to generate the frequency f2 can be carried out in an advantageous implementation based on the waveforms / protocol defined in IEEE 802.11ba (or an extension thereof), since IEEE 802.11ba is particularly well-suited for energy-saving receivers due to its special wake-up modulation.

[0055] The passive radio node can then transmit data to the first Wi-Fi device at the f2 frequency. This transmitted data is preferably compatible with the IEEE 802.11 b standard, as it uses a constant envelope for modulation. The data from the passive radio node could also be received by a second Wi-Fi device.

[0056] According to further embodiments, encryption of the transmitted and / or received data would also be possible. According to embodiments, the transmitted data for determining the frequency f2 from the signal at frequency fi can also be transmitted in encrypted form. This would prevent unaddressed passive radio nodes from being accidentally woken up. It would also prevent unauthorized waking of the passive radio nodes by third parties. Likewise, replay immunity can be achieved through alternating signaling.

[0057] The functions mentioned could be achieved, for example, by extending the existing security procedures in IEEE 802.11.

[0058] According to further embodiments, selectivity would also be possible. In this case, the system or transceiver can be supplemented with mechanisms for addressing different tags or tag populations differently, e.g., ID-selective, tag groups (function, manufacturer, by ID part, by WLAN key (possibly derived from SSID or WLAN identifier), etc.), or broadcast.

[0059] According to one embodiment, the reception of user data can also be enabled. For this purpose, the passive radio node could receive data from the first WLAN device on the frequency f2, which is then preferably compatible with the IEEE 802.11 b standard, since demodulation is simpler than with other modulation types used in WLAN. In an alternative approach, the data transmission from the first WLAN device to the passive radio node can also take place on the frequency fi based on IEEE 802.11 b1a.

[0060] In a further implementation, the modulator could also be implemented as BPSK, 2-ASK, OOK, etc. With regard to power-saving implementation, BPSK and 2-ASK (OOK) are preferred.

[0061] The transmission of the reference signal is explained below according to exemplary embodiments. One implementation option according to one exemplary embodiment is that the signal is transmitted continuously at frequency h for the entire communication of the tag. This is advantageous, for example, if the tag is a passive radio node that does not have an energy storage device. In an alternative approach, the signal at frequency T could also be switched off during communication at frequency f2. In this case, the radio node must have its own energy storage device or generate the signal using energy from an energy source other than signal T. This would have the advantage that the frequencies T and f2 could be significantly closer to each other.

[0062] In some countries, frequency hopping is required (e.g., according to FCC 15.247 in the USA), as is one example. Therefore, the frequency T could also change during communication of the passive radio node. Various approaches are conceivable to solve this problem.

[0063] Another possible implementation, according to one embodiment, is that the frequency f2 is determined only once at the beginning of communication from the signal with frequency fi. Therefore, the signal could even be switched off at frequency fi, or it could only be needed for power supply, whereby the exact frequency does not play a decisive role.

[0064] Another possibility, according to another embodiment, is that the frequency f2 is determined again from the signal T after the frequency hop. In this case, the new frequency is signaled, e.g., within the signal at the new frequency fi. In a third approach, according to another embodiment, the signaling occurs only once (or not after each frequency hop). Using data available in the passive radio node (e.g., a table or other calculation), the frequency f2 can be calculated based on the frequency h after the frequency hop.

[0065] In principle, the approaches mentioned can also be used in combination.

[0066] The reception of multiple reference signals (e.g., for frequency-hopping transmission signals) sequentially or simultaneously (multiple receivers in parallel) is possible according to embodiments. In this case, the device allows a change in the reception frequency fi or the configuration of multiple radio receivers.

[0067] According to embodiments, the use of multiple receive and / or transmit antennas is possible. For this purpose, for example, a receive-side and / or output-side antenna array is used. The receive and transmit antennas can, of course, also be combined according to further embodiments, just as the combination of receive and transmit arrays can be. The use of multiple receive antennas for receiving the reference signal(s) serves to achieve a diversity gain (e.g., if the signal at one antenna is in a "deep fade," it may be easily received at another if multiple antennas are used).

[0068] The possibility of measuring the first RF signal with the first carrier frequency f1 is explained below with reference to Fig. 3.

[0069] Fig. 3 shows the receiver path 20' with the components 20p for the preamplifier, 20d for the demodulator, 20q for the quantizer (here a comparator), and 20z for the counter. In the embodiment shown here, the preamplifier 20p receives the RF signal from the antenna 22, then outputs the preamplified signal RF2 to the demodulator 20d, which then extracts the AM signal from this. This signal is quantized (see signal DATA) and then evaluated accordingly using the counter 20z to obtain the output signal or reference signal CNT. All four of these elements are optional and can occur in combination or separately in a receive path 20'. This receive path 20' is explained in detail below using a specific implementation. In this proposed implementation, the receiver 20' consists of an RF amplifier 20p for boosting the signal level. The RF pre-amplifier 20p can be omitted or implemented in several stages.The demodulator 20d can, for example, be implemented as a BPSK or AM demodulator. An implementation based on an OOK (On-Off-Keying) envelope detector, as currently used in IEEE 802.11ba, would be particularly advantageous. For illustration purposes, an envelope detector is therefore assumed below. This can be implemented as a peak-value rectifier (e.g., with diodes or transistors) or as a voltage squarer with a low-pass filter (as an energy detector). A voltage or current signal AM is provided at the demodulator output, which is correlated with the RF carrier amplitude. Ideally, the demodulator is then an amplitude demodulator that outputs the carrier envelope as an analog signal. If the envelope detector is sensitive, in particular, to weak signals with a low voltage amplitude, this increases the overall maximum permissible distance from the transmitter of the signal with frequency fi. This value is also referred to as the read range.

[0070] In the downstream quantizer 20q – e.g., a comparator – a discrete-value signal (digital signal DATA) is generated by including an analog switching threshold Thr (“Threshold”). This is counted, for example, in an RF counter. The counter 20z, designed as a counter, is controlled, for example, by a CountEnable signal CE. The time period (later referred to as T12) of the active phase of the CE signal determines the counting duration. This is used to determine the frequency T of the received signal with the desired accuracy. Here, a counting time of 10 ps is chosen as an example, and the counter now counts up to 8657. The frequency T of the transmitted signal can be assumed to be 865.7 MHz, for example. In an advantageous implementation, the word width of the counter should fully cover the counting range for the frequency T. In an alternative implementation, however, a counter 20z with a smaller word width could be used, resulting in overflows.In this case, the overflows are designed in such a way that the transmission frequency fi can still be determined unambiguously (for example, only certain frequency ranges are permitted).

[0071] A further implementation is explained below with reference to Fig. 4. In contrast to the embodiment of Fig. 3, this one does not assume an unambiguous determination of f2, but rather only a valid edge grid, e.g., that of IEEE 802.11. Fig. 4 shows an implementation of the reference signal generator 34', which receives the CNT signal of the counter 20z or, in general, an internal reference as its input signal. In this embodiment, the RF signal generator 34 has two lookup tables 34L1 and 34L2. Both evaluate the CNT signal or the internal reference to output Div_R to the divider 34dr and Div_N to the divider 34dn. The divider 34dn or divider 34dn is implemented as a PLL, while the divider 34dr or divider 34dr is implemented as an RFID div and is designed to determine a reference frequency fREF.The counting result CNT is used to generate an internal frequency reference from the received signal with frequency T. On the other hand, a frequency setting of f2 is to be made for the radio transmitter within the device.

[0072] In an advantageous implementation, for example, this is an integer-N PLL synthesizer. This allows a frequency divider value Div_R to be derived from CNT. In this step, the divisor Div_R of the (preferably digital) frequency divider Divider_R is set. This is done by entering the counter value (here: 8657), e.g., into a look-up table (LUT) #1, where the divisor Div_R is set. The frequency divider Divider_R generates a (preferably digital) square wave of frequency f from the received signal at frequency fi. REF= h / Div_R. Instead of the LUT, a computing unit is also conceivable, which, for example, uses a mathematical algorithm to determine the values ​​for Div_R and Div_N. This allows the radio grid to be determined as a component of the second carrier frequency. A further development of this variant 34' into an entire transmitter module 30 is shown in Fig. 5.

[0073] Fig. 5 shows the input side of the element 34', which provides the reference signal f r of the frequency divider 34dr together with a signal fL 00pof the frequency divider 34dn to a phase detector 34pd. Downstream of this are a filter 34f, a VCO 34v, and an RF modulator 34m, which then outputs the second RF signal. Furthermore, the oscillator 34v is connected to the frequency divider 34dn via a feedback loop 34f. The operation of the transmitter module 30 is explained below. Accordingly, the divisor Div_N is also generated from the CNT value. Fig. 5 shows an example of the structure of a radio transmitter with an integer-N PLL; however, a frequency-locked loop is also conceivable, which only performs frequency comparisons and does not provide phase control. The voltage-controlled oscillator 34v (VCO) transmits at the frequency f2, here, for example, in the 2.4 GHz band.

[0074] The acquisition of the time reference is explained with reference to Fig. 6. Various methods for the precise determination of the frequency fi of the signal are explained below. Fig. 6 shows one possible OOK modulation as a special 2-ASK modulation. In an advantageous implementation, this could, for example, be signals according to IEEE 802.11 ba. Here, for example, correlation sequences - such as 32-bit long 2-ASK (or OOK) sequences - can be used for the precise temporal detection of timestamps. The exact frequency fi is determined by measuring the number of oscillations between two timestamps. In an alternative implementation, the frequency fi could also be determined multiple times over several sections in order to achieve greater robustness.

[0075] An example of a possible implementation according to embodiments could be as follows: The signaling of a defined time interval is carried out, for example, by a preceding transmission interval with low power (2-ASK: low level, i.e. zero for OOK) of duration T Pi between the times L and t2, as well as by a subsequent transmission interval of duration T P2between t3 and t4, again with a low transmission power level (2-ASK) or zero (OOK). Optionally, the entire telegram for transmitting the time reference can be initiated with a special wake-up sequence ("preamble"), e.g., as a 2-ASK or OOK telegram for detection with power-saving OOK / AM radio receivers. According to exemplary embodiments, the wake-up sequence can have a special correlation property comparable to pseudonoise sequences, especially if the preamble is detected in a fault-tolerant manner, e.g., with a correlator on the receiver side. If the autocorrelation function of the preamble is even similar to a Dirac unit pulse, i.e., with the characteristic of a sharp maximum and weak secondary maxima, the detection simultaneously also occurs as decoding of a system preamble, i.e., the recognition of a system-specific ID identifier.This allows for a pre-selection from the entire pool of radio signals with a precise and error-tolerant recognition of the agreed preamble. This can be done, for example, with two values ​​(binary) or multi-value (M-ASK), unipolar or bipolar. The longer the preamble is, the greater the chance of detection in the case of disturbed or noisy received signals. The intervals T. Pi and T P2do not necessarily have to have a reference character; it is sufficient if the time period TI2 is adhered to as precisely as possible. In this time period, according to embodiments, either an internal oscillator can be counted with a counter to determine the exact frequency, or the received signal of frequency fi can be recorded with a counter. This allows the device to independently determine the frequency T or to frequency calibrate an internal oscillator. In the case of counting fi, according to embodiments, an internal reference frequency can be generated based on the counter reading CNT by frequency-dividing the received signal of frequency fi with a frequency divider Div_R. This internal reference signal fREF can be used for an integer-N PLL synthesizer or a frequency-locked loop (FLL). This sets the frequency of an internal high-frequency oscillator (e.g., a VCO) to the transmission frequency f2.Another frequency divider, Divider_N, divides the VCO signal and feeds it to a comparator (e.g., phase-frequency detector PFD) in the PLL or FLL. The divisor is also derived from the counter reading CNT. This can be done arithmetically or in a predefined table ("look-up table"). The same applies to the divisor Div_R.

[0076] As soon as a sequence control activates the transmitter modulation, the transmission signal (as described above) is generated and suitably modulated at frequency f2 = fi / Div_R * Div_N according to the embodiments. Transmission methods such as those in the IEEE 802.11 ba standard or Bluetooth or other common modulation types are suitable for this, preferably BPSK, GFSK or even 2-ASK or OOK. The corresponding data rate for the modulation can optionally be provided with an additional counter block, e.g. from the already generated frequency reference fREF or from the received signal T. According to one embodiment, the transmission signal is to be modulated in such a way that common radio receivers for Bluetooth / Bluetooth Low Energy or Wireless LAN (IEEE 802.11, preferably specifically IEEE 802.11 ba) or for other radio standards can receive and decode the transmission signal. Frequency hopping methods can also be implemented with the device.For this purpose, according to one embodiment in the case of the PLL synthesizer, the divisor Div_N is modulated according to a predefined frequency hopping pattern for the transmission.

[0077] Overall, it is achieved that a suitable transmission signal (e.g. an RFID transmission signal) on the frequency fi with corresponding characteristics (described above) activates the device described here to generate a transmission signal on the frequency f2 for a possibly more distant radio receiver (e.g. Bluetooth / Bluetooth Low Energy or WLAN).

[0078] Additive and alternative features are explained below. According to one embodiment, a subcarrier can be used. In an alternative implementation, the receiver could also obtain the necessary time references from a subcarrier / subcarrier with information content or time references. For this purpose, the subcarrier could be transmitted with additional information that enables the necessary information to be obtained. For example, the information for deriving the frequency fi could be obtained from the difference between the main and subcarriers. In one possible implementation, the determination could be made directly from their frequency spacing.

[0079] Encryption can also be used according to embodiments. Furthermore, encrypted signaling can be agreed upon that is known only to the transmitting device for frequency h and the device described here. The signaling types can also be changed during each transmission process, so that a so-called replay attack is no longer possible for attacking third parties.

[0080] According to embodiments, selective waking of the transceiver is possible. The preamble and parts of the payload can be used for selective waking: Then, only specific implementations of this device are addressed individually or in groups, and not all devices within radio range. This allows for targeted data throughput to be increased and radio traffic to be minimized.

[0081] Further embodiments avoid collisions as follows: To avoid transmission collisions, the received signal of frequency T can also contain the time or time offset at which the receiving devices are permitted to transmit on frequency f2. This is intended to prevent simultaneous and then hardly usable transmission.

[0082] Obtaining the frequency solely from modulation and signaling is possible according to further embodiments. Another possibility would be to obtain the frequency solely from signaling and / or modulation or subcarriers. For example, time stamps could be signaled and a number of oscillations defined or signaled, from which a frequency can then be derived. An example of this would be that a time interval measurable for the radio node (e.g., via two signal edges at a certain time interval, e.g., 1 ms) is signaled and a number of oscillation cycles is defined or signaled (e.g., 10 6 ). From this, a frequency can then be derived (e.g. 10 6 / 1 ms = 1 GHz). It should be noted here that the RF signal generator generates the second RF signal based on the first carrier frequency and signal information, or alternatively, generates the second RF signal based on a frequency modulated onto the first RF signal and the signal information.

[0083] The signal information can, for example, be preconfigured, i.e. stored in a memory. In this case, it would be conceivable for several pieces of signal information, e.g. multipliers or dividers, to be stored in the memory and to be selectable. Alternatively, it would be conceivable for this signal information to be extracted from the signal. The result is that, depending on this information, the carrier frequencies can be varied relative to one another. The variation occurs depending on the variation in the signal information. Therefore, if signal information is received or loaded from the memory that has a first value, the resulting frequency difference is different than if the signal information (received or read in) has a different value.

[0084] Embodiments of the present invention thus advantageously create an IoT device with a corresponding radio receiver or a superheterodyne or superregenerative receiver. In principle, the radio signal receiving section can also be designed as a superheterodyne or superregenerative receiver. The power supply in the sense of energy harvesting does not necessarily limit the design of the receiver architecture to diode detectors. The decisive factor is the correspondingly low power consumption, matching the size of a capacitive energy storage device and the preceding charging time. The transmission signal can then be generated as described above. Derived from the reception frequency T, a further reference signal fREF2 can also be generated, e.g., for a second receiver at frequency fa. Thus, multiple radio receivers, e.g., at different reception frequencies, are conceivable, especially if they are designed to be frequency-selective.

[0085] Possible applications include use with a standard such as IEEE 802 (WLAN), e.g., for new sensor applications. This creates a large potential market for a wide variety of applications. Interesting applications exist primarily in the private consumer sector and for IoT applications in industrial environments. The receiver can be used in a mobile device or in a base station. Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device.Some or all of the method steps may be performed by (or using) a hardware device, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the essential method steps may be performed by such a device.

[0086] Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory, a hard disk, or other magnetic or optical storage device storing electronically readable control signals that can interact or cooperate with a programmable computer system to perform the respective method. Therefore, the digital storage medium may be computer-readable.

[0087] Some embodiments according to the invention thus comprise a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is carried out.

[0088] In general, embodiments of the present invention may be implemented as a computer program product having a program code, wherein the program code is effective to perform one of the methods when the computer program product is run on a computer.

[0089] The program code can, for example, also be stored on a machine-readable medium. Other embodiments include the computer program for performing one of the methods described herein, wherein the computer program is stored on a machine-readable medium. In other words, one embodiment of the method according to the invention is thus a computer program that has program code for performing one of the methods described herein when the computer program is executed on a computer.

[0090] A further embodiment of the method according to the invention is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded.

[0091] A further embodiment of the method according to the invention is thus a data stream or a sequence of signals that represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can be configured, for example, to be transferred via a data communication connection, for example, via the Internet.

[0092] A further embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to carry out one of the methods described herein.

[0093] A further embodiment comprises a computer on which the computer program for performing one of the methods described herein is installed.

[0094] A further embodiment according to the invention comprises a device or system designed to transmit a computer program for performing at least one of the methods described herein to a recipient. The transmission can be electronic or optical, for example. The recipient can be, for example, a computer, a mobile device, a storage device, or a similar device. The device or system can, for example, comprise a file server for transmitting the computer program to the recipient.

[0095] In some embodiments, a programmable logic device (e.g., a field-programmable gate array, an FPGA) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC.

[0096] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

1. Transceiver (10) comprises a receiver unit (20) and a transmitter unit (30), wherein the receiver unit (20) is designed to receive a first RF signal having a first carrier frequency (f1); wherein the transmitter unit (30) comprises an RF signal generator (34) which is designed to generate a second RF signal having a second carrier frequency (f2) on the basis of the first carrier frequency (f1) or a frequency modulated onto the first RF signal and signal information (I), wherein the second carrier frequency (f2) is different from a first carrier frequency (f1).

2. Transceiver (10) according to claim 1, wherein the second carrier frequency (f2) is variable depending on the signal information (I); and / or wherein the signal information (I) can represent two or more different states, depending on which the second carrier frequency (f2) is varied.

3. The transceiver (10) according to any one of the preceding claims, wherein the receiving unit is configured to extract information contained or encrypted in the first RF signal or in a further signal as the signal information; and / or wherein the receiving unit is configured to extract the signal information from a modulation in the first RF signal; and / or wherein the signal information is preconfigured.

4. Transceiver (10) according to one of the preceding claims, wherein the receiver unit (20) is designed to determine the first carrier frequency (f1) or the modulated frequency or a reference (R) dependent on the first carrier frequency (f1) or the modulated frequency.

5. T ransceiver (10) according to one of the preceding claims, wherein the signal generator generates the second carrier frequency (f2) in dependence on the first carrier frequency (f1) by frequency dividing or modulating or frequency shifting the first carrier frequency (f1) or by supplementing the first RF signal.

6. Transceiver (10) according to one of the preceding claims, which has means for providing energy (40), in particular RF-to-DC energy harvesting means, which are designed to harvest electrical energy from a radio field or the first RF signal or to harvest electrical energy from a radio field or the first RF signal and to vary the frequency to be harvested by means of a matching network, or which are designed to harvest electrical energy from another energy form; and / or which have an energy store (40) which is designed to store electrical energy.

7. Transceiver (10) according to one of the preceding claims, wherein the first carrier frequency (f1) lies in a sub-1 GHz frequency range, or wherein the first carrier frequency (f1) is defined by a center frequency of one of the IEEE802.11b / g / n / ac channels; and / or wherein the second carrier frequency (f2) lies in a 2.4 GHz frequency range or sub-5 GHz range or a frequency range specified by IEEE802.11b / ba channels; and / or wherein the first carrier frequency (f1) lies in a sub-5 GHz frequency range; and / or wherein the second carrier frequency (f2) lies in a sub-10 GHz frequency range.

8. Transceiver (10) according to one of the preceding claims, wherein the second carrier frequency (f2) is based on the first carrier frequency (f1) of an initially applied the first RF signal or a continuously applied first RF signal is determined and / or wherein the first RF signal is only applied or evaluated initially, after a frequency jump or permanently.

9. Transceiver (10) according to one of the preceding claims, which further comprises a modulator which is designed to modulate data packets onto the second carrier frequency (f2), or in particular to modulate them by means of BPSK, GFSK, 2-ASK and / or OOK.

10. Transceiver (10) according to one of the preceding claims, comprising a preamplifier (20p) and / or a demodulator (20d) and / or a quantizer (20q), in particular an ADC comparator, and / or a counter (20z).

11. The transceiver (10) according to claim 10, wherein the quantizer (20q) is configured to output discrete signals for determining the first carrier frequency (f1) using a threshold value; and / or wherein the counter (20z) is configured to determine the first carrier frequency (f1) by counting the number of oscillations between two time stamps in the first RF signal in one or more sections of the first RF signal and / or to determine a channel spacing of the first carrier frequency (f1); and / or wherein the demodulator (20d) is configured to provide a voltage or current signal correlated with an RF carrier amplitude and / or comprises an OOK envelope detector.

12. Transceiver (10) according to one of the preceding claims, wherein the transmitter unit (30) comprises a frequency divider which is designed to derive frequency division values ​​Div_R from an internal reference (R) derived from the first carrier frequency (f1) or from the first carrier frequency (f1) and / or wherein the transmitter unit comprises a lookup table which is designed to provide a square-wave signal based on the first carrier frequency (f1) or on an internal reference (R) derived from the first carrier frequency.

13. Transceiver (10) according to claim 12, wherein the frequency divider comprises an integer-N PLL synthesizer and / or a frequency-locked loop (FLL) and / or a further divider, or wherein the frequency divider comprises an integer-N PLL synthesizer and / or a frequency-locked loop (FLL) and / or a further divider, and wherein the integer-N PLL synthesizer and / or frequency-locked loop (FLL) and / or further divider is designed to determine the second carrier frequency (f2) based on the first carrier frequency or an internal reference derived from the first carrier frequency (f1) or to determine the second carrier frequency f2 based on the first carrier frequency f1 using the formula f2 = f1 / Div_R * Div_N (where Div_R comprises a frequency division value and Div_N is based on the internal reference (R) / using a frequency hopping pattern).

14. The transceiver (10) according to one of the preceding claims, wherein the signal information comprises a multiplier or divider on the first carrier frequency (f1) or on the modulated frequency; and / or wherein the RF signal generator is configured to generate the second RF signal with a frequency hopping pattern with at least two second carrier frequencies defined by the signal information.

15. Transceiver (10) according to one of the preceding claims, wherein the counter is designed to determine the first carrier frequency (f1) in a main carrier or a subcarrier of the first RF signal or by deriving an offset between a main carrier and a subcarrier.

16. Transceiver (10) according to one of the preceding claims, wherein the receiver unit (20) is configured to receive a plurality of frequencies and / or a plurality of first RF signals and / or wherein the transmitter unit comprises a plurality of RF signal generators configured to generate a plurality of second RF signals; and / or wherein the receiver unit (20) is configured to receive payload data at the first (f1) and / or second carrier frequency (f2); and / or wherein the transmitter unit is configured to transmit payload data at the first (f1) and / or second carrier frequency (f2).

17. The transceiver (10) according to any one of the preceding claims, wherein the receiver unit (20) is configured to receive a frequency within the preamble of the first RF signal as a wake-up signal and / or ID-selective information and / or ID-selective information as a wake-up signal and / or address information and / or ID-selective information as a wake-up signal; and / or wherein the preamble is 2-valued (binary) or multi-valued; and / or wherein the receiver unit (20) is configured to respond to a wake-up signal or ID-selective or receiver-selective or encrypted wake-up signal.

18. Passive IoT device, superheterodyne or superregenerative receiver with a transceiver (10) according to one of the preceding claims.

19. A method for operating a transceiver (10) according to any one of claims 1-17, comprising the following steps: Receiving a first RF signal having a first carrier frequency (f1); Generating a second RF signal with a second carrier frequency (f2) based on the first carrier frequency (f1) or a frequency modulated onto the first RF signal and signal information, wherein the second carrier frequency (f2) is different from a first carrier frequency (f1).

20. A computer program for performing the steps of the method of claim 19.

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