Frequency-shifting backscattering transmission

Abstract

Various examples of the disclosure relate to a frequency-shifting backscattering transmission. The carrier frequency (272) of an information-carrying signal of the backscattering transmission is an integer multiple of the carrier frequency (271) of an excitation signal of the backscattering transmission.

Description

[0001] D E S C R I P T I O N

[0002] FREQUENCY-SHIFTING BACKSCATTERING TRANSMISSION

[0003] TECHNICAL FIELD

[0004] Various examples of the disclosure relate to a backscattering transmission. Various examples of the disclosure specifically relate to a frequency-shifting backscattering transmission.

[0005] BACKGROUND

[0006] Modern data transmission relies in many cases on wireless transmission. Conventional radio transmission requires nodes providing information to generate radio signals using device components such as digital-to-analog converters (DACs), mixers, oscillators and power amplifiers and nodes obtaining the information using components low noise amplifiers, mixers, oscillators, and analog-to-digital converters (ADCs) to receive the radio signals. Usually, devices participating in wireless active radio transmission are battery powered and the aforementioned components for wireless communication consume a substantial amount of the energy provided by the battery. Hence, the batteries need to be recharged or replaced regularly. With an increasing amount of battery powered devices participation in wireless communication, this may not be feasible anymore. For example, a number of one trillion Internet-of-things (IOT) devices worldwide each having 10-year battery lifetime would already imply that 274 billion batteries would have to be changed every single day. However, in several use cases a 10-year battery lifetime may not even be achievable with known technologies. Moreover, battery recycling is still insufficient. In 2018, 191 000 tons of portable batteries were sold in the European Union but only less than half of said quantity, i.e. 88 000 tons of used portable batteries, is collected as waste to be recycled. The demand for new batteries has to be reduced, too, in view of the limited natural resources required for battery production.

[0007] To mitigate such limitations and drawbacks of convention radio transmission, backscattering transmission has been proposed, e.g., in WO 2024 / 056530 A1. Here, the node providing information is not required to generate its own radio frequency (RF) signal , but rather modulates an excitation signal by selectively absorbing the excitation signal; this is achieved by adjusting an impedance coupled to the antenna. Thereby, an information-carrying signal that is modulated to carry the information I data can be received at a receiving node of the backscattering transmission.

[0008] Conventional backscattering transmission faces certain restrictions and drawbacks. For instance, the information-carrying signal uses the same carrier frequency as the excitation signal. For a device that implements, both, a transmitting node transmitting the excitation signal as well as a receiving node of the backscattering transmission receiving the information-carrying signal, a full duplex (FD) transceiver hardware is required. The FD transceiver hardware is comparatively complex and / or bulky. FD transceiver hardware can be challenging to implement and / or costly. Furthermore, the full-duplex backscattering transmission may increase interference towards other devices. Document IEEE 802.11-23 / 0876r0 entitled “X-Band Operation fo AMP” discloses a backscatter modulation employing cross-band operation. A sub-GHz frequency is used in downlink and 2.4 GHz is used for uplink communication. Thus, a frequency shift is present between the excitation signal of the backscattering transmission and the information-carrying signal of the backscattering transmission. The radio-frequency (RF) hardware components for such technology are comparatively complex and require significant power, e.g., may require frequency synthetization and mixing.

[0009] SUMMARY

[0010] Accordingly, a need exists for advanced backscattering transmissions. In particular, a need exists for advanced frequency-shifting backscattering transmissions. A need exists for frequency-shifting backscattering transmissions that can be implemented using low power consumption at the device implementing the backscattering node of the backscattering transmission. A need exists for frequency-shifting backscattering transmissions causing reduced interference to other devices.

[0011] This need is met by the features of the independent claims. The features of the dependent claims define embodiments.

[0012] A method for use in a device of a communication system. The method includes establishing a configuration of a backscattering transmission. The backscattering transmission includes an excitation signal having a first carrier frequency and an information-carrying signal having a second carrier frequency. The second carrier frequency being an integer multiple of the first carrier frequency. The method also includes configuring the backscattering transmission based on the configuration.

[0013] A device is disclosed. The device configured for communication in a communication system, the device comprising a circuitry configured for: establishing a configuration of a backscattering transmission, the backscattering transmission comprising an excitation signal having a first carrier frequency and an information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and configuring the backscattering transmission based on the configuration.

[0014] A backscattering device is disclosed. The backscattering device includes circuitry for picking-up an excitation signal having a first carrier frequency and applying a non-linear signal modification operation and a modulation operation to the excitation signal, to obtain an information-carrying signal, the information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency. The circuitry is also for radiating the information-carrying signal.

[0015] It is to be understood that the features mentioned above and those yet to be explained below may be used not only in the respective combinations indicated, but also in other combinations or in isolation without departing from the scope of the invention.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 schematically illustrates a backscattering transmission in a bistatic deployment according to various examples. FIG. 2 schematically illustrates a backscattering transmission in a monostatic deployment according to various examples.

[0018] FIG. 3 schematically illustrates a backscattering transmission in a monostatic deployment according to various examples.

[0019] FIG. 4 schematically illustrates a backscattering transmission in a monostatic deployment according to various examples.

[0020] FIG. 5 schematically illustrates a communication system including a cellular network and multiple wireless user devices connected to the cellular network according to various examples.

[0021] FIG. 6 schematically illustrates a device according to various examples.

[0022] FIG. 7A schematically illustrates a radio-frequency circuitry for load modulation at a backscattering device according to various examples.

[0023] FIG. 7B schematically illustrates a radio-frequency circuitry for a non-linear signal manipulation operation at a backscattering device according to various examples.

[0024] FIG. 70 schematically illustrates a radio-frequency circuitry for a non-linear signal manipulation operation at a backscattering device according to various examples.

[0025] FIG. 8 schematically illustrates a relative arrangement of frequency bands of a frequency-division duplex configuration of a cellular network and carrier frequencies of a backscattering transmission according to various examples.

[0026] FIG. 9 schematically illustrates a relative arrangement of frequency bands of a frequency-division duplex configuration of a cellular network and carrier frequencies of a backscattering transmission according to various examples.

[0027] FIG. 10 schematically illustrates a relative arrangement of frequency bands of a frequency-division duplex configuration of a cellular network and carrier frequencies of a backscattering transmission according to various examples.

[0028] FIG. 11 schematically illustrates a relative arrangement of frequency bands of a frequency-division duplex configuration of a cellular network and carrier frequencies of a backscattering transmission according to various examples.

[0029] FIG. 12 is a flowchart of a method according to various examples.

[0030] FIG. 13 is a flowchart of a method according to various examples.

[0031] FIG. 14 is a flowchart of a method according to various examples.

[0032] FIG. 15 is a signaling diagram according to various examples.

[0033] FIG. 16 is a signaling diagram according to various examples.

[0034] FIG. 17 is a signaling diagram according to various examples.

[0035] DETAILED DESCRIPTION

[0036] Some examples of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the functionality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and / or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical device disclosed herein may include any number of microcontrollers, a graphics processor unit (GPU), integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), or other suitable variants thereof), and software which co-act with one another to perform operation(s) disclosed herein. In addition, any one or more of the electrical devices may be configured to execute a program code that is embodied in a non-transitory computer readable medium programmed to perform any number of the functions as disclosed.

[0037] In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the disclosure is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only.

[0038] The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0039] Hereinafter, techniques for implementing a backscattering transmission are disclosed. In a backscattering transmission, a backscattering node of the backscattering transmission modifies an excitation signal incident from a transmitting node of the backscattering transmission, to thereby convey data to a receiving node of the backscattering transmission. The transmitting node transmits the excitation signal, typically a continuous wave, towards the backscattering node. This excitation signal serves as a carrier for the data or information that the backscattering node intends to transmit. The backscattering node modulates the incident excitation signal. Typically, the modulation used is low-complexity modulation schemes such as ON-OFF-keying (OOK), binary frequency shift keying, binary phase shift keying. These modulations are achieved by switching the impedance of the RF interface at the backscattering node between two states. These states correspond to the binary values in the informationcarrying signal departing from the backscattering node. This varies the amplitude of the information-carrying signal between an OFF-state and an ON-state. The receiving node then detects these variations in the signal amplitude of the information-carrying signal. The information-carrying signal is demodulated to retrieve the information carried by the informationcarrying signal.

[0040] According to various examples of the present disclosure, a frequency-shifting backscattering transmission is employed: Here, the carrier frequency of the excitation signal is different than the carrier frequency of the information-carrying signal. According to various examples of the present disclosure, the carrier frequency of the information-carrying signal ( _2) is an integer multiple of the carrier frequency of the excitation signal (f_l). I.e., f2= n x , wherein n = 2,3, ....

[0041] This choice of the frequency relationship of the carrier frequencies of the excitation signal and the information-carrying signal enables a comparatively simple implementation of the RF circuitry at the device implementing the backscattering node (backscattering device). The backscattering device picks-up the excitation signal and applies a non-linear signal modification operation as well as a modulation operation to the excitation signal. The information-carrying signal is obtained and radiated. Such non-linear signal modification operation may be implemented by a passive RF element such as a diode. Active RF elements such as a mixer may not be required at least in some examples. This reduces the overall power consumption at the backscattering device, e.g., if compared to a backscattering device operating as described in IEEE 802.11-23 / 0876r0 on arbitrary frequency ratios. However, an active RF element may still be used in some scenarios. For instance, an oscillator that locks-in to the harmonic may be assumed to enhance the output power and would still avoid the frequency synthetization, a further band filtering of the selected frequency.

[0042] The backscattering node may be implemented by various types of backscattering devices, e.g., an IOT device. For instance, the backscattering device may have a limited battery capacity or may not have a battery at all. For instance, a capacitor may be pre-charged and provide sufficient energy for device operation. Accordingly, the RF circuitry at the backscattering device may not drain the energy storage or only drain the energy storage of the device at a rate that is significantly smaller than for conventional active wireless transmission.

[0043] As a general rule, according to the disclosed examples, coexistence between the backscattering transmission and cellular communication, e.g., downlink (DL) transmission from the cellular network to terminals (UEs) and uplink (UL) transmission from UEs to the cellular network, is facilitated. In particular, the carrier frequency of the excitation signal as well as the carrier frequency of the information-carrying signal may be within one or bands for which resources are scheduled by the cellular network.

[0044] For such coexistence of cellular communication and the backscattering transmission in the similar frequency regions, there is a risk of interference being caused by the backscattering transmission negatively affecting the cellular communication.

[0045] Using the frequency-shifting backscattering transmission enables to reduce interference. For instance, the excitation signal may reside a DL partition of a spectrum under scheduling control of a cellular network. The information-carrying signal, on the other hand, may reside in an UL partition. The DL partition and the UL partition may be bands of a frequency-duplex division (FDD) configuration of the cellular network.

[0046] In further detail, the present disclosure illustrates techniques of establishing a configuration of such frequency-shifting backscattering transmission. As a general rule, such configuration may be static, semi-static, or dynamic.

[0047] As a general rule, the configuration may be determined at a given (physical) implementing a control node of the frequency-shifting backscattering transmission and may be communicated to one more further device implementing other nodes of the frequency-shifting backscattering transmission, e.g., a transmitting node and / or a receiving node and / or a backscattering node.

[0048] The configuration can include various information content, e.g., one or more of the carrier frequencies of the involved signals such as the excitation signal and the informationcarrying signal, a relationship - e.g., distance in frequency domain, ratio (e.g., an integer ratio), etc. - between one or more of the carrier frequencies of the excitation signal on the one hand and the carrier frequency of the information-carrying signal on the other hand, one or more properties of a non-linear operation or obtaining the information-carrying signal, and / or time scheduling information of the excitation signal.

[0049] Sometimes, such configuration may be determined based on a predefined mapping between locations of one or more of the nodes of the frequency-shifting backscattering transmission and candidate configurations. This reduces the amount of control signaling overhead required, because the node may locally determine the configuration based on knowledge of its position. Furthermore, such configuration may be determined based on monitoring the spectrum; for instance, the backscattering node may auto-detect the excitation signals which may have characteristic patterns.

[0050] FIG. 1 schematically illustrates a communication system (bi-static deployment) according to various examples. The bi-static communication system includes a device 61, a device 65, and a device 69. In the scenario of FIG. 1 , the device 61 - e.g., a BS of a cellular network implementing a Third Generation Partnership Project (3GPP) protocol (also, non-cellular communication networks are conceivable in which case the device 61 may implement another type of access point device) - implements a transmitting node 101 of a backscattering transmission 190 as well as a control node 110 of the backscattering transmission 190. The transmitting node 101 transmits an excitation signal 111. The excitation signal 111 may be a single tone excitation signal or a multitone excitation signal.

[0051] The device 65 (e.g., an IOT device) implements a backscattering node 105 of the backscattering transmission 190. The backscattering device 65 picks up the excitation signal 111 and applies a non-linear signal modification operation to the excitation signal 111. This yields another signal that can be modulated - based on a data stream encoding information to be communicated - to obtain an information-carrying signal 113. The carrier frequency of the information-carrying signal 113 is different than the carrier frequency of the excitation signal 111 (frequency shift).

[0052] According to examples, to enable a simple nonlinear signal modification operation, the ratio between the carrier frequency of the information-carrying signal 113 and the carrier frequency of the excitation signal 111 is an integer larger than 1, i.e., 2, 3, 4, etc. thus, a harmonic of the excitation signal 111 can be relied upon, alleviating the need for active RF elements such as a mixer. The information-carrying signal is then radiated by the backscattering device 65.

[0053] The device 69 - here, a UE - implements a receiving node 109 of the backscattering transmission 190 that is configured to receive the information-carrying signal 113 and to demodulate the information-carrying signal 113, to retrieve the information. FIG. 1 is only one example configuration of a communication system that can benefit from the techniques disclosed herein. Other scenarios are illustrated in FIG. 2 (mono-static deployment in which the BS 61 implements the transmitter node 101 and the receiver node 109), FIG. 3 (mono-static deployment in which the UE 69 implements the transmitter node 101 and the receiver node 109), and FIG. 4 (similar to FIG. 3, but control node 110 is implemented by BS 61).

[0054] Next, details with respect to the control node 110 are disclosed. Typically, the control node 110 may be implemented by an access point device of a communication system, e.g., by a base station of a cellular network. According to the disclosed techniques, the control node 110 can provide various control functionality with respect to the backscattering transmission 190. For instance, the control node 110 can maintain a repository which indicates whether the certain UEs support or not support an FD operation. The control node 110 may obtain respective control messages that are indicative of such support of the FD operation from UEs. Alternatively or additionally, further capability information associated with the various UEs can be obtained at the control node 110 and processed for selecting the appropriate UE to participate in the backscattering transmission 190. Example capabilities include the supported frequency ratios of a FD operation.

[0055] The control node 110 may be in control of scheduling of resources for the backscattering transmission 190. This may include providing scheduling information to the participating devices. Such scheduling information may be indicative of transmit resources for transmitting the excitation signal and / or of receive resources for receiving the information-carrying signal. In particular, transmit resources may be arranged in an uplink partition of the frequency spectrum under scheduling control of a cellular network; this is, in particular, helpful of the transmitting node 101 is implemented by a UE, to mitigate interference. Furthermore, power restrictions or other constraints of the transmitting of the excitation signal may be set by the control node 110.

[0056] The control node 110 may trigger one or more devices to participate in the backscattering transmission. This may include triggering a device implementing the transmitting node 101 (e.g., a transmit point) to transmit the excitation signal; and / or triggering a device implementing the receiving node to attempt receiving the information-carrying signal.

[0057] The control node 110 may process requests for backscattering transmissions, e.g., from UEs and / or backscattering devices. This can include allocating respective resources to each backscattering transmission and / or acknowledging respective requests.

[0058] As a general rule, various scenarios are conceivable with respect to which device implements the transmitter node 101 , the receiver node 101 as well as the control node 110. In particular, it would be possible, as illustrated in FIG. 4, that the control node 110 is implemented by a device - e.g., the BS 61 - that does not directly participate in the transmitting and / or receiving of the backscattering transmission 190.

[0059] FIG. 5 schematically illustrates a communication system 50 according to various examples. The communication system 50 includes a cellular network 51. The cellular network 51 includes multiple BSs 52, 53. A UE 55 is connected to the cellular network 51 through the BS 52; and a UE 56 is connected to the cellular network 51 through the BS 53. The backscattering device 59 may be an IOT device. The BS 52 may be configured as the BS 61 previously discussed in connection with FIG. 1 , FIG. 2, FIG. 3, in FIG. 4. The BS 53 may be configured as the BS 61 previously discussed in connection with FIG. 1 , FIG. 2, FIG. 3, in FIG. 4. The UE 55 may be configured as the UE 69 previously discussed in connection with FIG. 1 , FIG. 2, FIG. 3, in FIG. 4. The UE 56 may be configured as the UE 69 previously discussed in connection with FIG. 1, FIG. 2, FIG. 3, in FIG. 4. The backscattering device 59 may be configured as the backscattering device 65 previously discussed in connection with FIG. 1, FIG. 2, FIG. 3, in FIG. 4. Any one of the UEs 55, 56 may be capable of implementing the transmitting node 101 and / or the receiving node 109 of the backscattering transmission 190. Alternatively or additionally, any one of the BSs 52, 53 may be capable to implement the transmitting node 101 and / or the receiving node 109.

[0060] FIG. 6 schematically illustrates a device 200 according to various examples. For example, the device 200 may implement any of the devices 61 , 62, 65, 69 previously discussed in connection with FIG.1 , FIG. 2, FIG. 3, and FIG. 4 or any one of the devices 52, 53, 55, 56, 59 as previously discussed in connection with FIG. 5.

[0061] The device 200 includes a processor 211 , a communication interface 213, and a memory 212. Communication over a radio spectrum is possible via the communication interface 213. For example, an active wireless transmission of an excitation signal of a backscattering transmission can be implemented. It would also be possible for a picked-up signal to be radiated in a modulated manner, as previously discussed in connection with the backscattering node 105 of the device 65. It would also be possible to receive and demodulate an informationcarrying signal. The communication interface 213 may not only implement physical layer functionality, i.e., spectrum access, but may also implement higher layers of a transmission protocol stack, e.g., to provide control messages or to receive control messages. The processor 211 may load program code from the memory 212 and execute the program code. Upon executing the program code, the processor 211 may be configured to: implement a transmitting node of a backscattering transmission; implement a backscattering node of a backscattering transmission; implement a receiving node of a backscattering transmission; transmit an excitation signal; pick-up an excitation signal; apply a non-linear signal modification operation to a picked-up excitation signals to obtain a further signal and modulate the further signal to obtain an information-carrying signal; radiate the information-carrying signal; receive an informationcarrying signal; demodulate an information-carrying signal; and so on.

[0062] FIG. 7A schematically illustrates RF circuitry 313 that may be part of the communication interface 213 of the respective device 59, 65, 200 that implements the backscattering node. The RF circuitry 313 enables low-power or zero-power communication of information. For this, the information-carrying signal 113 - which may be obtained, according to the disclosed techniques, from a non-linear signal modification operation that is based on an excitation signal (details on how to obtain the information-carrying signal 113 will be explained below in FIG. 8) - is either absorbed or transmitted. Transmission can be achieved by setting the switch 302 to the position in which it is connected to ground; in this scenario, there is an impedance mismatch, so that the signal is not absorbed but radiated via the antenna (possibly using an amplifier that is not shown in FIG. 7A). Absorption can be achieved by setting the switch 302 to the position in which it is connected to the impedance-matched load 303. The switch is actuated by a circuitry 304 that applies a certain modulation scheme, typically on-off-keying, to an incoming bitstream 305 that encodes the information to be communicated.

[0063] FIG. 7B illustrates aspects with respect to obtaining nonlinear signal modification operation 800. The picked-up excitation signal 111 is fed to a non-linear component 711 e.g., a passive component such as a diode. This results in a spectrum of signals being output, at the base frequency of the input but also at the harmonics at multiple integer frequencies of the base frequency. A bandpass filter 712 may be used to select a given one of the harmonics, e.g., the first harmonic in which case the signal 113 has a frequency of f2= 2 x , wherein fa is the frequency of the signal 111. The signal 113 thus obtained can be modulated as shown in FIG. 7A.

[0064] Instead of using a passive nonlinear component 711 followed by a bandpass filter 712, an active RF element may be used; an example is an oscillator 713 that is locked into the particular harmonic, cf. FIG. 7C. Also, such a scenario would avoid frequency synthetization.

[0065] FIG. 8, FIG. 9, FIG. 10, and FIG. 11 illustrate various options for mapping the carrier frequency 271 of the excitation signal 111 and the carrier frequency 262 of the informationcarrying signal 113 to an UL partition - here, implemented by an UL band 252 - as well as a DL partition - here, implemented by a DL band 251 - of the cellular network 51.

[0066] For example, FIG. 8 (both carrier frequencies 271 , 272 in one or more UL partitions) may be helpful for a monostatic deployment scenario in which a UE implements the transmitting and receiving nodes, e.g., as shown in FIG. 3.

[0067] For example, FIG. 9 (carrier frequency 271 in a DL partition while the carrier frequency 262 is in an UL partition) may be helpful for a bi-static deployment scenario in which a BS implements a transmitter node, cf. FIG. 1.

[0068] For example, FIG. 10 (both carrier frequencies 271, 272 in one or more DL partitions) may be helpful in a monostatic deployment scenario in which a BS implements the transmitting and receiving nodes, e.g., as shown in FIG. 3.

[0069] In FIG. 11 , both carrier frequencies 271 , 272 are in the DL band 251.

[0070] While above in connection with FIG. 8, FIG. 9, FIG. 10, and FIG. 11 scenarios have been illustrated in which, both, the carrier frequency 271 of the excitation signal 111 as well as the carrier frequency 262 of the information having carrying signal 113 are located within the frequency bands under scheduling control of the cellular network, in some scenarios, the information-carrying signal may be out-of-band, e.g., in an open spectrum not under scheduling control of the cellular network.

[0071] FIG. 12 is a flowchart of a method according to various examples. The method is for use in a device such as any one of the devices 61, 69, 52, 53, 55, 56, 200 previously discussed. For instance, the method of FIG. 12 may be executed by a processor upon loading program code from a memory and upon executing the program code. For instance, the method of FIG. 12 may be executed by the processor 211 of the device 200, upon loading program code from the memory 212 and upon executing the program code (cf. FIG. 6).

[0072] The method of FIG. 12 is for use in a device that implements a control node of a frequency-shifting backscattering transmission. The control node determines the configuration of the backscattering transmission and, if applicable, shares that configuration with one or more further devices that participate in the backscattering transmission. It is possible, but not mandatory, that the device that implements the control node also implements, e.g., the transmitting node or the receiving node or both the transmitting and receiving notes of the backscattering transmission.

[0073] In typical scenarios, the device that implements the control node of the frequencyshifting backscattering transmission is a BS of a cellular network. It is also conceivable that multiple BSs of a cellular network jointly implement the control node, e.g., by coordinating resources allocated to the backscattering transmission, selecting the appropriate UEs as transmitting node and / or receiving node for serving a given backscattering device, etc.

[0074] At box 3105, indications of a capability of one or more further devices that potentially participate in the backscattering transmission are obtained. A 3GPP Radio Resource Control (RRC) control message may be obtained.

[0075] The capability obtained at box 3105 may, e.g., pertain to the capability of the respective device (e.g., a UE) to implement, both, a transmitting node and a receiving node of the frequency-shifting backscattering transmission. For instance, a full duplex (FD) capability of the device may be indicated, i.e. , the device may indicate whether it can contemporaneously transmit the excitation signal and received the information-carrying signal. A given UE may indicate whether it supports or does not support FD operation.

[0076] Alternatively or additionally, supported frequency ratios of the carrier frequencies 271, 272 of the excitation signal 111 and the information-carrying signal 113 can be indicated. For instance, certain UEs may support FD operation while other UEs may not support FD operation. For instance, even amongst those UEs that support FD operation, different UEs may be limited with respect to the supported frequency ratios between transmitting and receiving. Such information may be included in the signaling of box 3105.

[0077] Above, certain aspects with respect to support of FD operation by devices that can potentially implement the transmitting node and / or receiving node of the backscattering transmission have been disclosed. Alternatively or additionally, at box 3105, an indication may be obtained from a backscattering device, the indication being indicative of the backscattering device supporting the frequency-shifting backscattering transmission. I.e., support of the backscattering device to shift the frequency of the incident excitation signal to a multiple integer thereof may be signaled. One or more constraints or properties of a non-linear signal modification operation may be signaled. Supported frequency ratios may be signaled.

[0078] At box 3110, location reports of one or more devices - e.g., the same devices for which the capability indication is obtained at box 3105 - may be obtained. Such location report may indicate the geo-position of the device. The location report may indicate a serving cell of a cellular network to which the devices connected.

[0079] Alternatively or additionally to the location report of one or more devices that potentially implement a transmitting node and / or a receiving node of the backscattering transmission, a location report of a backscattering device may be obtained.

[0080] At box 3111 , a discovery procedure may be optionally triggered or executed. For instance, in one implementation of box 3111 , one or more UEs that have reported their FD operation support or that are otherwise candidates for implementing a transmitting node and / or a receiving node of the backscattering transmission, may be mandated to transmit a frequency- tuned excitation signal in one or more frequency bands of the discovery procedure. Thereby, backscattering devices in vicinities of those UEs may be discovered. The time and frequency resources used for the discovery procedure may be particularly protected. Upon discovering a backscattering device, the respective UE can provide a report thereof. For instance, one or more properties of the backscattering device can be indicated, e.g., its capability to apply a nonlinear signal modification operation to an incident excitation signal, thereby yielding the information-carrying signal at an integer multiple frequency of the incident excitation signal. The supported frequency ratios may be indicated. If the control node is implemented by a BS, then the BS may also participate in the discovery procedure. I.e., the BS may also actively transmit a frequency-tuned excitation signal to discover any backscattering devices in its vicinity.

[0081] Generally, such discovery procedure is helpful in scenarios in which the backscattering device does not employ active transmission for a control channel but employs in band control signaling also via the backscattering transmission. In-band signaling of capabilities, and / or properties, etc. of the backscattering device can be achieved using the discovery procedure.

[0082] At box 3115, a configuration of the frequency-shifting backscattering transmission is determined. Various information can be taken into account when determining the configuration. For instance, information is obtained at box 3105 and / or at box 3110 may be taken into account. A geo-location to configuration mapping may be employed. Certain constraints imposed by the cellular network or another communication system, e.g., bands available for communication, frequencies under control of a scheduler, etc. can be taken into account. At box 3120, a control message indicative of at least a part configuration determined at box 3115 is optionally provided to one or more devices, e.g., a device selected in accordance with the capability of box 3105 and / or the location of box 3110. For instance, a certain part of the configuration may be fixedly determined based on the reported geolocation of a given device. In such case, the device may also be aware of that part of the configuration; in such a scenario, only the remaining part of the configuration may need to be signaled to that device.

[0083] Next, details with respect to the configuration will be explained. As a general rule, the configuration of the frequency-shifting backscattering transmission as discussed herein may include various information elements.

[0084] For instance, the configuration may include the carrier frequency of the excitation signal and / or may include the carrier frequency of the information-carrying signal. For instance, the configuration may include the frequency ratio between the two carrier frequencies. For instance, the configuration may include an integer value, string, a field including a pointer, etc. that specifies this frequency ratio.

[0085] The configuration may include scheduling information, e.g., transmit resources defined in time and / or frequency domain, so that the device implementing the transmitting node of the backscattering transmission can transmit the excitation signal at these transmit resources. Alternatively or additionally, such scheduling information may include associated receive resources defined in time and / or frequency domain, so that the device implementing the receiving node of the backscattering transmission can receive the information-carrying signal at these receive resources. Cellular communication may be muted or otherwise protected against interference at the transmit resources and / or the receive resources.

[0086] For instance, if a UE supporting FD operation is configured to implement, both, the transmitting node as well as the receiving node of the backscattering transmission, then the configuration provided at box 3120 to that UE may be indicative of transmit resources and receive resources at the two different carrier frequencies of the excitation signal and the information-carrying signal, respectively. The transmit and receive resources may be contemporaneous, i.e., occur at the same or at least overlapping time intervals.

[0087] Alternatively or additionally to configuring one or more devices that implement a transmitting node and / or a receiving node of the backscattering transmission, at box 3120, it is also possible to provide a configuration to the backscattering device that implements the backscattering node of the backscattering transmission.

[0088] The configuration may be provided, at box 3120, by means of one or more control messages. For instance, multiple control messages may be provided to multiple devices. Example control messages include RRC control messages. For instance, scheduling information may be provided to one or more devices using Layer 1 control messages, e.g., Downlink Control Information (DCI). Other parts of the configuration may be provided using higher-layer control messages, e.g., Layer 3 control messages such as RRC control messages.

[0089] If at least a part of the configuration is to be provided to, both, an active device such as a UE, e.g., implementing the transmit node or the received node of the backscattering transmission, as well as to the backscattering device implementing the backscattering node, then different types of control messages may be used for delivering the information to the UE on the one hand and the backscattering device on the other hand. For example, in-band configuration of the backscattering device may be possible.

[0090] It is not mandatory for all implementation scenarios to provide such control message at box 3120. For instance, in some scenarios it would be possible that the control node and the transmitting node and the receiving node are all co-located, e.g., in a BS. Such a scenario has been discussed above in connection with FIG. 2. Also, the backscattering node may be fixedly pre-configured, e.g., using one or more parameter values as revealed in the discovery procedure of box 3111. Then, it is not required to provide any control messages to inform other devices of the configuration.

[0091] In a scenario in which the control node is co-located with the transmitting node and the receiving node, the excitation signal is transmitted at box 3135 and the information-carrying signal is received at box 3140. The respective transmitting and receiving parameter values of the RF circuitry are accordingly set at box 3130 in accordance with the configuration previously determined at box 3115, thereby configuring the backscattering transmission 190.

[0092] If, on the other hand, the control node determining the configuration at box 3115 does not implement at least one of the transmitting node or the receiving node of the backscattering transmission, then, at box 3120, a respective control message indicative of the configuration can be provided to the respective device that implements the transmitting node and / or the receiving node. For instance, it would be possible that a certain UE implements, both, the transmitting node 101 as well as the receiving node 109 using FD operation, a scenario previously discussed in connection with FIG. 4. In such a scenario, the control node 110 implemented by the BS 61 determines the configuration and provides the configuration to the UE implementing, both, the transmitting node as well as the receiving node. That UE supports FD operation, e.g., as previously indicated by the UE at box 3105 to the control node. The control node may select this UE because of its support of the FD operation. Other selection criteria include its geolocation and / or channel strength between the UE and the backscattering device.

[0093] FIG. 12 illustrates a scenario in which the configuration of the backscattering transmission is determined at box 3115. Such determining of the configuration of the backscattering transmission is typically a task implemented by the control node associated with the backscattering transmission. In another scenario, illustrated in FIG. 13, establishing the configuration is achieved by obtaining a respective control message that is indicative of the configuration (determined by another device / node).

[0094] FIG. 13 is a flowchart of a method according to various examples. The method is for use in a device such as any one of the devices 61 , 69, 52, 53, 55, 56, 200 previously discussed. For instance, the method of FIG. 13 may be executed by a processor upon loading program code from a memory and upon executing the program code. For instance, the method of FIG. 13 may be executed by the processor 211 of the device 200, upon loading program code from the memory 212 and upon executing the program code (cf. FIG. 6).

[0095] The method of FIG. 13 is for use in a device that does not implement the control node of the frequency-shifting backscattering transmission. Thus, establishing the configuration of the backscattering transmission includes obtaining a message that is indicative of at least a part of the configuration (other parts may be fixedly preconfigured). Then, based on the configuration, a transmitter and / or receiver parameter of RF circuitry are set, to thereby configure the backscattering transmission. The message indicative of at least a part of the configuration is obtained from the device implementing the control node, typically a BS of the cellular network.

[0096] The method of FIG. 13 may be executed by a UE that is connected to the cellular network through a certain BS.

[0097] At box 3005, the device provides a control message that is indicative of its support or nonsupport of FD operation and / or other capability parameters. Box 3005 is inter-related with box 3105 of the method of FIG. 12.

[0098] At box 3010, the device provides a location report. Box 3010 is inter-related with box 3110 of the method of FIG. 12.

[0099] At box 3015, the device may optionally perform a discovery procedure. As part of the discovery procedure, a certain frequency band or multiple frequency bands may be scanned. I.e., an excitation signal is transmitted using a tuned carrier frequency, to test whether any backscattering device responds at a given carrier frequency. One or more backscattering devices in the vicinity can be detected. It can be tested whether the backscattering device supports various frequency ratios between the carrier frequency of the excitation signal on the one hand and the carrier frequency of the information-carrying signal on the other hand. The radio channel between the device and the backscattering device can be tested. For instance, a signal level of the information-carrying signal can be measured.

[0100] Upon discovering or not discovering a certain backscattering device, at box 3015, a respective report message may be provided to a control node of the cellular network. This corresponds to what has been previously explained in box 3111 of the method of FIG. 12. The report message may be indicative of presence or absence of a given backscattering device. An identity of the backscattering device may be reported. One or channel properties of a radio channel between the device and the backscattering device may be reported. It may be reported whether the backscattering device supports a frequency-shifting backscattering transmission. Supported frequency ratios may be reported.

[0101] At box 3020, a control message indicative of at least a part of the configuration of the backscattering transmission is obtained. The configuration may be determined by a control node of the backscattering transmission, e.g., as previously explained in connection with box 3115 of the method of FIG. 12. Thus, establishing the configuration includes obtaining, e.g. receiving, a respective control message from another device.

[0102] It is optionally possible, at box 3035, to configure the backscattering device based on the configuration as indicated by the control message obtained at box 3020. Such a scenario may be applicable if the particular device executing the method of FIG. 13 has previously discovered the backscattering device in its vicinity, at box 3015.

[0103] At box 3040, transmit and / or receive parameters of RF circuitry are set so that at box 3045 the excitation signal may be transmitted and / or at box 3050 the information-carrying signal may be received. This is in accordance with the configuration as at least partly obtained at box 3020.

[0104] FIG. 14 is a flowchart of a method according to various examples. The method is for use in a backscattering device such as the backscattering device 65 or the backscattering device 59 or the device 200.

[0105] At box 3205, the backscattering device may participate in a discovery procedure. This may include responding to the discovery excitation signal transmitted by a UE or a BS in the vicinity of the backscattering device. Respective techniques have been previously discussed in connection with box 3111 in FIG. 12 as well as in connection with box 3015 in FIG. 13.

[0106] Next, at box 3210, the backscattering device may obtain at least a part of a configuration of the backscattering procedure. For instance, the backscattering device may obtain values of any dynamic parameters such as time-frequency resources for picking up an excitation signal and time-frequency resources for radiating the information-carrying signal of the backscattering transmission.

[0107] At box 3215, the backscattering device picks up the excitation signal and then, at box 3220 applies a non-linear single modification operation. Also, the thus obtained signal is modulated, e.g., using OOK modulation. Respective techniques have been previously discussed in connection with FIG. 7A, FIG. 7B, and FIG. 7C. Then, at box 3225, the thus obtain information-carrying signal is radiated.

[0108] FIG. 15 is a signaling diagram of signaling taking place between the devices 61, 69, 65 implementing the control node 110, the transmitting node 101 as well as the backscattering node 105, respectively. In the scenario FIG. 15, a mono-static deployment scenario of a backscattering transmission 190 is shown. This includes FD operation at the UE 69.

[0109] At 5005, the UE 69 implementing, both, the transmitting node 101 as well as the receiving node 109, provides a control message 4005 (e.g., a RRC control message on a Physical Shared Uplink Channel) indicative of its support of the FD operation to the BS 61 implementing the control node 110. Thus, 5005 corresponds to box 3005 of the method of FIG. 13 as well as to box 3105 of the method of FIG. 12.

[0110] In the scenario of FIG. 15, the control message 4005 provided, at 5005, by the UE 69 includes a request for a configuration of a backscattering transmission between the UE 69 and the backscattering device 65: The UE 69 and the backscattering device 65 are previously paired at 5001 , e.g., using Near Field Communication or a Radio Frequency Identification (RFID) tag.

[0111] Accordingly, the BS 61 implementing the control node 110 then provides, at 5010, the configuration 4010. This includes scheduling information, i.e. , specific time and frequency resources for transmitting the excitation signal 111 and receiving the information-carrying signal 113. The transmit resources and receive resources are in accordance with a frequency ratio that is supported by the FD operation of the UE 69. Then, the backscattering transmission 190 is executed, at 5020 (cf. box 3040, box 3045, and box 3050 in FIG. 13). Any data obtained by the UE 69 via the information-carrying signal 113 may be locally processed and / or provided to another node or server via the BS 61 , as indicated by the data message 4020 communicated between the UE 69 and the BS 61 at 5025.

[0112] FIG. 16 illustrates a variant of FIG. 15; while FIG. 15 is a mono-static deployment scenario, FIG. 16 is a bi-static deployment scenario in which the BS 61 implements the receiving node 109. Here, it is particularly helpful to use a frequency allocation as shown in FIG. 9, to mitigate interference.

[0113] FIG. 17 is a signaling diagram of signaling taking place between the devices 52, 53, 55, 56, and 59. The BSs 52, 53 jointly implement the control node 110 of a backscattering transmission. Backbone signaling can facilitate such split functionality.

[0114] FIG. 17 generally corresponds to a configuration phase of the backscattering transmission.

[0115] At 5205, the UE 55 as well as the UE 56 both provide control messages 4005 that are indicated for of these UEs 55, 56 supporting the FD operation.

[0116] Then, the control node 110 provides a configuration 4110 at 5210 to the UE 55 as well as to the UE 56. The configuration 4110 requires the UE 55 as well as the UE 56 to execute a discovery procedure 890. Here, at 5215, the UE 55 transmits the excitation signal 111 at multiple frequencies within a defined frequency band, e.g., as indicated by the configuration 4110. Similarly, at 5220, the UE 56 transmits the excitation signal at the multiple frequencies. Contemporaneously to transmitting the excitation signal 111 the UE 55 attempts to receive the information-carrying signal 113; the UE 56 acts similarly.

[0117] In the illustrated scenario FIG. 17, the UE 55 is out-of-coverage of the backscattering device 59 so that the backscattering device 59 does not respond to the excitation signal 111 transmitted by the UE 55. On the other hand, the backscattering device 59 is in-coverage of the UE 56 which responds to the excitation signal 111 transmitted by the UE 56 at 5220 with the radiation of the information-carrying signal 113 that is then detected by the UE 56. The UE 55 as well as the UE 56 provide respective report messages 4115 at 5225 to the control node 110. The control node 110 may then - at 5230 - provide a respective configuration 4120 to the UE 56, requesting the UE 56 to implement the transmitting node 101 and / or the receiving node 109.

[0118] As part of the discovery procedure 890, support of certain operating modes may be indicated by the backscattering device 59. For instance, data encoded by the informationcarrying signal 113 and the discovery procedure 890 may be indicative of the support of the frequency-shifting backscattering transmission by the backscattering device 59. For instance, the supported frequency ratios may be signaled. A certain ID code may be signaled such that a respective lookup can be performed. Instead of signaling the supported frequency ratios, it would also be possible to scan through all possible frequency combinations. Then, the particular frequency combination having the highest gain may be selected.

[0119] Summarizing, techniques of operating a backscattering device have been disclosed. A frequency translation is used to convert the carrier frequency of an incident excitation signal to an integer multiple, by selecting a harmonic of the initial carrier frequency is obtained from a nonlinear signal modification operation. Thus, the relation between the carrier frequency of the radiated signal and the incident excitation signal is an integer multiple. The radiated signal is also modulated to carry information. Thereby, a backscattering transmission is implemented.

[0120] For instance, the respective backscattering device may indicate its support of the frequency-shifting backscattering transmission to a control node, e.g., as part of a registration procedure or as part of a discovery procedure. For instance, another device - e.g., a BS of the cellular network or a UE - may scan a certain frequency band as part of the discovery procedure.

[0121] UEs may indicate their support of FD operation, i.e. , their support of contemporaneously transmitting an excitation signal and receiving the information-carrying signal of the backscattering transmission. For instance, the supported frequency ratios of the carrier frequencies of the excitation signal and the information-carrying signal may be indicated. For instance, this may be achieved by reference to existing UL / DL partitions of a cellular network to which that UE is connected. In such a case, a control node of the backscattering transmission may select the appropriate the UE for implementing the transmitting and receiving node of the backscattering transmission in a monostatic deployment scenario. That UE can then be configured with the appropriate transmit and receive resources for transmitting the excitation signal and receiving the information-carrying signal. Such selection may - alternatively or additionally to the support of the full duplex operation - be based on a position / location of the UE, e.g., relatively to the position or location of the backscattering device. Also, user-based triggers are conceivable.

[0122] As a general rule, a backscattering transmission may be triggered by a user, by the cellular network and / or by an event. A user may request the backscattering transmission.

[0123] Summarizing, at least the following EXAMPLES have been disclosed.

[0124] EXAMPLE 1. A method for use in a device (52, 53, 55, 56, 61 , 69) of a communication system (50), the method comprising: - establishing (3115, 3020) a configuration of a backscattering transmission (190), the backscattering transmission (190) comprising an excitation signal (111) having a first carrier frequency (261) and an information-carrying signal (113) having a second carrier frequency (262), the second carrier frequency (262) being an integer multiple of the first carrier frequency (261), and

[0125] - configuring (3120, 3130, 3035, 3040) the backscattering transmission (190) based on the configuration.

[0126] EXAMPLE 2. The method of EXAMPLE 1 , wherein the configuration comprises at least one of the first carrier frequency or the second carrier frequency.

[0127] EXAMPLE S. The method of EXAMPLE 2, wherein the configuration comprises the integer multiple.

[0128] EXAMPLE 4. The method of any one of the preceding EXAMPLES, wherein the device is an access point device of a communication network, wherein said configuring comprises providing, to a wireless communication device connected to the communication network via the access point device, at least one message indicative of at least a part of the configuration.

[0129] EXAMPLE S. The method of EXAMPLE 4, wherein the at least one message comprises scheduling information indicative of at least one of transmit resources at the first carrier frequency or contemporaneous receive resources at the second carrier frequency.

[0130] EXAMPLE 6. The method of any one of EXAMPLES 4 to 5, further comprising:

[0131] - obtaining, from multiple wireless communication devices messages, indicative of support or non-support of full-duplex operation of each wireless communication device, and

[0132] - selecting the wireless communication device from the multiple wireless communication devices depending on the messages.

[0133] EXAMPLE 7. The method of any one of EXAMPLES 1 to 3, wherein the device is a wireless communication device connected to a communication network through an access point device of the communication network, wherein said establishing of the configuration comprises obtaining, from the access point device, at least one message indicative of at least a part of the configuration.

[0134] EXAMPLE 8. The method of EXAMPLE 7, wherein the at least one message comprises scheduling information indicative of at least one of transmit resources at the first carrier frequency or receive resources at the second carrier frequency.

[0135] EXAMPLE 9. The method of EXAMPLE 7 or 8, wherein said configuring comprises setting at least one of a transmitter parameter or a receiver parameter in accordance with the configuration.

[0136] EXAMPLE 10. The method of any one of the preceding EXAMPLES, wherein the first carrier frequency and the second carrier frequency are within one or more bands for which resources are scheduled by a communication network, the device being associated with the communication network. EXAMPLE 11. The method of EXAMPLE 10, wherein the first carrier frequency is in a downlink partition of the one or more bands and wherein the second carrier frequency is in an uplink partition of the one or more bands, or wherein the first carrier frequency and the second carrier frequency are both in an uplink partition of the one or more bands.

[0137] EXAMPLE 12. The method of any one of the preceding EXAMPLES,

[0138] - obtaining a message indicative of one or more frequency ratios supported by a backscattering device implementing a backscattering node of the backscattering transmission (190), wherein the first carrier frequency and the second carrier frequency are in accordance with the one or more frequency ratios supported by the backscattering device.

[0139] EXAMPLE 13. The method of EXAMPLE 12, wherein the one or more frequency ratios are determined based on a discovery procedure performed by the device or another device.

[0140] EXAMPLE 14. The method of any one of the preceding EXAMPLES,

[0141] The second signal being obtained from a nonlinear signal modification operation at a backscattering device of the backscattering transmission.

[0142] EXAMPLE 15. A method for use in a backscattering device (59, 65), the method comprising:

[0143] - picking-up an excitation signal having a first carrier frequency,

[0144] - applying a non-linear signal modification operation and a modulation operation to the excitation signal, to obtain an information-carrying signal, the information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and

[0145] - radiating the information-carrying signal.

[0146] EXAMPLE 16. The method of EXAMPLE 15, wherein the non-linear signal modification operation is executed by one or more passive radio-frequency components generating at least one harmonic of the first carrier frequency.

[0147] EXAMPLE 17. A device (52, 53, 55, 56, 61 , 69) configured for communication in a communication system, the device comprising a circuitry configured for:

[0148] - establishing (3115, 3020, 3025) a configuration of a backscattering transmission, the backscattering transmission comprising an excitation signal having a first carrier frequency and an information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and

[0149] - configuring (3120, 3125, 3130, 3035, 3040) the backscattering transmission based on the configuration.

[0150] EXAMPLE 18. The device of EXAMPLE 17, wherein the circuitry is configured for executing the method of any one of EXAMPLES 1 to 14.

[0151] EXAMPLE 19. A backscattering device (59, 65) comprising circuitry for:

[0152] - picking-up an excitation signal having a first carrier frequency, - applying a non-linear signal modification operation and a modulation operation to the excitation signal, to obtain an information-carrying signal, the information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and

[0153] - radiating the information-carrying signal.

[0154] EXAMPLE 20. The backscattering device of EXAMPLE 19, wherein the circuitry comprises one or more passive radio-frequency components for applying the non-linear signal modification operation, thereby generating at least one harmonic of the first carrier frequency.

[0155] Although the disclosure has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present disclosure includes all such equivalents and modifications and is limited only by the scope of the appended claims.

[0156] For illustration, various examples have been disclosed above in the framework of a cellular network. Other implementation scenarios are conceivable. For instance, a communication system must not necessarily implement a cellular network. Also, non-cellular technologies may benefit from the techniques disclosed herein.

[0157] For further illustration, various examples have been disclosed in which a transmitting node of the backscattering transmission is implemented by a BS of a cellular network. Other nodes may implement the transmitting node, e.g., a specific transmit point configured for transmitting the excitation signal (but, e.g., no other signals or no general active transmission of the cellular network).

[0158] For still further illustration, messages and / or signals mentioned the above (e.g., configuration (or a configuration message), control message, capability, location report message, excitation signal, information-carrying signal) may be respectively communicated by using various layer signaling or protocol messages. The various layer signaling or protocol messages herein may include L3 (Layer 3) signaling (e.g. RRC signaling, RRC message), L2 signaling (e.g. Medium Access Control (MAC) Control Element (CE)), Physical layer signaling (e.g. Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH)). Additionally or alternatively, the various layer signaling or protocol messages herein may include a layer signaling or a protocol message defined dedicated for Ambient loT capable device (e.g., the backscattering device). For instance, a new layer or a new protocol dedicated for A loT capable device (e.g., backscattering device) may be newly introduced. So, the various layer signaling or protocol messages herein may include A loT capable device specific layer signaling or A loT capable device specific protocol message. Especially, a new physical channel to communicate the excitation signal may be newly introduced. The new physical channel may be called as Physical Carrier Wave Channel (PCWCH) or Physical Excitation Channel (PECH).

Claims

C L A I M S1. A method for use in a device of a communication system , the method comprising:- establishing a configuration of a backscattering transmission, the backscattering transmission comprising an excitation signal having a first carrier frequency and an informationcarrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and- configuring the backscattering transmission based on the configuration.

2. The method of claim 1 , wherein the configuration comprises at least one of the first carrier frequency or the second carrier frequency.

3. The method of claim 2, wherein the configuration comprises the integer multiple.

4. The method of claim 1 , wherein the device is an access point device of a communication network, wherein said configuring comprises providing, to a wireless communication device connected to the communication network via the access point device, at least one message indicative of at least a part of the configuration.

5. The method of claim 4, wherein the at least one message comprises scheduling information indicative of at least one of transmit resources at the first carrier frequency or contemporaneous receive resources at the second carrier frequency.

6. The method of claim 4, further comprising:- obtaining, from multiple wireless communication devices messages, indicative of support or non-support of full-duplex operation of each wireless communication device, and- selecting the wireless communication device from the multiple wireless communication devices depending on the messages.

7. The method of claim 1, wherein the device is a wireless communication device connected to a communication network through an access point device of the communication network, wherein said establishing of the configuration comprises obtaining, from the access point device, at least one message indicative of at least a part of the configuration.

8. The method of claim 7, wherein the at least one message comprises scheduling information indicative of at least one of transmit resources at the first carrier frequency or receive resources at the second carrier frequency.

9. The method of claim 7, wherein said configuring comprises setting at least one of a transmitter parameter or a receiver parameter in accordance with the configuration.

10. The method of claim 1 ,wherein the first carrier frequency and the second carrier frequency are within one or more bands for which resources are scheduled by a communication network, the device being associated with the communication network.

11. The method of claim 10 wherein the first carrier frequency is in a downlink partition of the one or more bands and wherein the second carrier frequency is in an uplink partition of the one or more bands, or wherein the first carrier frequency and the second carrier frequency are both in an uplink partition of the one or more bands.

12. The method of claim 1,- obtaining a message indicative of one or more frequency ratios supported by a backscattering device implementing a backscattering node of the backscattering transmission, wherein the first carrier frequency and the second carrier frequency are in accordance with the one or more frequency ratios supported by the backscattering device.

13. The method of claim 12, wherein the one or more frequency ratios are determined based on a discovery procedure performed by the device or another device.

14. The method of claim 1,The second signal being obtained from a nonlinear signal modification operation at a backscattering device of the backscattering transmission.

15. A method for use in a backscattering device, the method comprising:- picking-up an excitation signal having a first carrier frequency,- applying a non-linear signal modification operation and a modulation operation to the excitation signal, to obtain an information-carrying signal, the information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and- radiating the information-carrying signal.

16. The method of claim 15, wherein the non-linear signal modification operation is executed by one or more passive radiofrequency components generating at least one harmonic of the first carrier frequency.

17. A device configured for communication in a communication system, the device comprising a circuitry configured for:- establishing a configuration of a backscattering transmission, the backscattering transmission comprising an excitation signal having a first carrier frequency and an informationcarrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and- configuring the backscattering transmission based on the configuration.

18. A backscattering device comprising circuitry for:- picking-up an excitation signal having a first carrier frequency,- applying a non-linear signal modification operation and a modulation operation to the excitation signal, to obtain an information-carrying signal, the information-carrying signal having a second carrier frequency, the second carrier frequency being an integer multiple of the first carrier frequency, and- radiating the information-carrying signal.

19. The backscattering device of claim 18, wherein the circuitry comprises one or more passive radio-frequency components for applying the non-linear signal modification operation, thereby generating at least one harmonic of the first carrier frequency.Although the disclosure has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present disclosure includes all such equivalents and modifications and is limited only by the scope of the appended claims.

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