Apparatus and method for passive terminal discovery

Abstract

There is provided an apparatus comprising: at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, generate at least one program code; the apparatus is caused to perform at least: a configuration of receiving at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscatter passive terminal discovery signal from at least one passive radio; and reporting the measured backscatter at least to the network node.

Description

Technical Field

[0001] Various example embodiments relate to passive terminal discovery. Background Art

[0002] In recent years, the number of Internet of Things (IoT) connections has grown rapidly. IoT devices with low cost and power consumption are required. Summary of the invention

[0003] According to some aspects, the subject matter of independent claims is provided. Some example embodiments are defined in the dependent claims. The scope of protection sought for the various example embodiments is set forth by the independent claims. The example embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims will be interpreted as examples that can be used to understand the various example embodiments.

[0004] According to a first aspect, an apparatus is provided, comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: receiving a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from at least one passive radio device; and reporting at least the measured backscatter to the network node.

[0005] According to a second aspect, an apparatus is provided, comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: configuration of transmitting at least one passive terminal discovery signal associated with at least one passive radio device to at least one active radio device; triggering reception and / or transmission of at least one passive terminal discovery signal; receiving from at least one active radio device at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by the at least one active radio device; and determining whether to associate at least one active radio device with at least one detected passive radio device based on the measured backscatter received from the at least one active radio device.

[0006] According to a third aspect, a method is provided, comprising: receiving, by an active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from at least one passive radio device; and reporting at least the measured backscatter to the network node.

[0007] According to a fourth aspect, a method is provided, comprising: transmitting, by a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device to at least one active radio device; triggering reception and / or transmission of at least one passive terminal discovery signal; receiving, from at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by the at least one active radio device; and determining, based on the measured backscatter received from the at least one active radio device, whether to associate the at least one active radio device with the at least one detected passive radio device.

[0008] According to a fifth aspect, an apparatus is provided, comprising components for performing the following: receiving a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from at least one passive radio device; and reporting at least the measured backscatter to the network node.

[0009] According to a sixth aspect, an apparatus is provided, comprising components for performing the following: transmitting a configuration of at least one passive terminal discovery signal associated with at least one passive radio device to at least one active radio device; triggering reception and / or transmission of at least one passive terminal discovery signal; receiving from at least one active radio device at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by the at least one active radio device; and determining whether to associate at least one active radio device with at least one detected passive radio device based on the measured backscatter received from the at least one active radio device.

[0010] According to a seventh aspect, a computer-readable medium is provided, comprising program instructions, which, when executed by at least one processor, cause the apparatus to at least perform: receiving a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from at least one passive radio device; and reporting at least the measured backscatter to the network node.

[0011] According to an eighth aspect, a computer-readable medium is provided, comprising program instructions, which, when executed by at least one processor, cause an apparatus to at least perform: transmitting a configuration of at least one passive terminal discovery signal associated with at least one passive radio device to at least one active radio device; triggering reception and / or transmission of at least one passive terminal discovery signal; receiving from at least one active radio device at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by at least one active radio device; and determining whether to associate at least one active radio device with at least one detected passive radio device based on the measured backscatter received from at least one active radio device.

[0012] According to a ninth aspect, a computer program is provided, which is configured to, when run on an apparatus, cause the apparatus to execute a method, the method comprising: receiving a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from at least one passive radio device; and reporting at least the measured backscatter to the network node.

[0013] According to a tenth aspect, a computer program is provided, which is configured to, when running on an apparatus, cause the apparatus to perform a method, the method comprising: transmitting a configuration of at least one passive terminal discovery signal associated with at least one passive radio device to at least one active radio device; triggering reception and / or transmission of at least one passive terminal discovery signal; receiving from at least one active radio device at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by the at least one active radio device; and determining whether to associate at least one active radio device with at least one detected passive radio device based on the measured backscatter received from the at least one active radio device.

[0014] According to the eleventh aspect, a device is provided, comprising: an energy harvester; at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the device to at least perform: receiving at least one passive terminal discovery signal; harvesting energy from at least the received passive terminal discovery signal using the energy harvester; generating at least one backscattered passive terminal discovery signal based at least on the harvested energy if the received passive terminal discovery signal includes a subsignature associated with the device; and avoiding generating at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include a subsignature associated with the device; and transmitting at least one backscattered passive terminal discovery signal if at least one backscattered passive terminal discovery signal is generated.

[0015] According to the twelfth aspect, a method is provided, comprising: receiving at least one passive terminal discovery signal by a passive radio device; using an energy harvester to harvest energy from at least the received passive terminal discovery signal; if the received passive terminal discovery signal includes a sub-signature associated with the device, generating at least one backscattered passive terminal discovery signal based on at least the harvested energy; and if the received passive terminal discovery signal does not include a sub-signature associated with the device, avoiding generating at least one backscattered passive terminal discovery signal; and if at least one backscattered passive terminal discovery signal is generated, transmitting at least one backscattered passive terminal discovery signal.

[0016] According to the thirteenth aspect, a device is provided, comprising components for: receiving at least one passive terminal discovery signal; using an energy harvester to harvest energy from at least the received passive terminal discovery signal; if the received passive terminal discovery signal includes a sub-signature associated with the device, generating at least one backscattered passive terminal discovery signal based on at least the harvested energy; and if the received passive terminal discovery signal does not include a sub-signature associated with the device, avoiding generating at least one backscattered passive terminal discovery signal; and if at least one backscattered passive terminal discovery signal is generated, transmitting at least one backscattered passive terminal discovery signal.

[0017] According to a fourteenth aspect, there is provided a computer program configured to, when executed on a device, cause the device to perform the method according to the thirteenth aspect.

[0018] According to a fifteenth aspect, there is provided a computer program which, when configured to be executed on a device, causes the device to execute the method according to the thirteenth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1Backscatter communications are shown by way of example;

[0020] Figure 2 A passive terminal discovery signal is shown by way of example;

[0021] Figure 3 The signaling between entities is shown by way of example;

[0022] Figure 4 The signaling between entities is shown by way of example;

[0023] Figure 5 The signaling between entities is shown by way of example;

[0024] Figure 6 The signaling between entities is shown by way of example;

[0025] Figure 7 A flow chart of the method is shown by way of example;

[0026] Figure 8 A flow chart of the method is shown by way of example;

[0027] Fig. 9 A block diagram of the apparatus is shown by way of example; and

[0028] Fig.10 A flow chart of a method is shown by way of example. DETAILED DESCRIPTION

[0029] Devices with reduced capabilities have been proposed to meet the requirements of low-cost and low-power devices for wide-area IoT communications. For example, IoT devices that communicate via new radio (NR) communication technology via narrowband (NB) IoT modules consume even hundreds of milliwatts of power for transmission and reception.

[0030] To achieve even lower cost and power consumption, battery-less devices can be used in IoT technology. Battery-less IoT devices are beneficial in the sense that the batteries of the IoT device do not need to be replaced. An example of a battery-less device is a passive radio frequency identification (RFID) tag. The power consumption of a commercial passive RFID tag can be as low as about 1 microwatt. The technology that enables this low power consumption is envelope detection for downlink data reception, and backscatter communication for uplink data transmission. RFID technology is designed for short-range communication, with a typical effective range of less than 10 meters.

[0031] Figure 1Backscatter communication is shown by way of example. In backscatter communication, a backscatter transmitter 120 (e.g., an RFID tag) reflects a carrier wave 130 sent by a reader 110 after modifying one or more characteristics of the received signal to embed information into the signal. The information embedded in the signal can be tag-specific information, such as the identity of the tag or any data that the tag can collect. The backscatter signal 140 is a signal generated by the tag in response to hearing an activation signal. The characteristics of the signal may include, for example, amplitude, phase, or center frequency. By modifying the signal, the tag 120 can achieve data transmission without generating a carrier wave itself. Communication via reflection rather than active radiation reduces the radio frequency (RF) front end of the tag to a single transistor switch, which minimizes manufacturing costs and energy requirements.

[0032] The tag can be configured to encode a signal to be reflected with a unique identity (ID) to achieve a unique signal. Then, a device that can perform a determination based on information about the original signal sent by the reader and based on information about the reflected signal knows which signal is the original signal and which signal is the reflected signal. For example, the device can be a positioning device, and the determination can be the positioning of the tag.

[0033] The tag 120 may be a passive radio device or a passive device or a passive terminal, such as a passive IoT device. A passive IoT device refers to an IoT device without a power source. A passive IoT device or terminal may capture and collect energy through energy harvesting, such as by collecting radio waves emitted from the network side. For example, a passive radio device may be associated with a passive terminal. That is, a passive terminal may include a passive radio device. In at least some embodiments, the passive device may be a semi-passive device, such as a semi-passive tag. A semi-passive tag may use a battery to run a circuit, but use the harvested energy for communication.

[0034] The reader 110 may be an active device or an active radio or an active wireless device. An active device refers to a device having a power source. For example, the active device may be a user device such as a mobile phone. An active device is configured to communicate with a network (e.g., with a network node such as a gNB). For example, an active device may be a user device such as a NR UE, a road side unit (RSU), a small cell network node (e.g., a gNB), etc.

[0035] The passive device or devices may communicate directly with a network, such as a NR network. Alternatively, the passive device or devices may communicate indirectly with the network, such as via one or more active devices, such as NR UEs.

[0036] A radio access architecture based on Long Term Evolution Advanced (LTE-Advanced, LTE-A) or New Radio (NR), also known as the fifth generation (5G), is used as an example of an access architecture. It is obvious to those skilled in the art that the embodiments can also be applied to other types of communication networks (e.g., 6G or WiFi) that have suitable means by appropriately adjusting parameters and procedures.

[0037] The active device is configured to wirelessly connect to an access node (such as a gNB, i.e., next generation NodeB) or an eNB (i.e., evolved NodeB (eNodeB)) on one or more communication channels in the cell, thereby providing the cell. The physical link from the user equipment to the network node is called the uplink (UL) or reverse link, and the physical link from the network node to the user equipment is called the downlink (DL) or forward link. It should be understood that the network node or its functions can be implemented by using any node, host, server, or access point entity suitable for such use. The communication system typically includes more than one network node, in which case the network nodes may also be configured to communicate with each other through links designed for the purpose, wired or wireless. These links may be used for signaling purposes. A network node is a computing device configured to control the radio resources of the communication system to which it is coupled. The network node may also be referred to as a base station (BS), an access point, or any other type of interface device, including a relay station capable of operating in a wireless environment. The network node includes or is coupled to a transceiver. A connection is provided from the transceiver of the network node to an antenna unit, which establishes a bidirectional radio link to the user equipment. The antenna unit may include multiple antennas or antenna elements. The network node is also connected to a core network (CN or Next Generation Core Network NGC).

[0038] User equipment or user device UE generally refers to a portable computing device including a wireless mobile communication device operating with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), cell phones, devices using wireless modems (alarm or measurement devices, etc.), laptop computers and / or touch screen computers, tablet computers, game consoles, notebooks, and multimedia devices. A user device may also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which objects are provided with the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction.

[0039] 5G enables the use of Multiple-Input Multiple-Output (MIMO) technology on both the UE and gNB side, more base stations or nodes than LTE (the so-called small cell concept), including macro sites operating in collaboration with smaller stations, and the adoption of various radio technologies depending on service needs, usage and / or available spectrum. 5G mobile communications support a wide range of use cases and related applications, including video streaming, augmented reality, different ways of sharing data, and various forms of machine-type applications (such as (massive) machine-type communications (mMTC), including vehicle safety, different sensors, and real-time control. 5G is expected to have multiple radio interfaces. That is, below 7 GHz, cmWave, and mmWave, and can also be integrated with existing traditional radio access technologies (such as LTE). The frequency range below 7 GHz can be referred to as FR1, and above 24 GHz (or more precisely, 24-52.6 GHz) can be referred to as FR2. The integration with LTE can be implemented as a system, at least in the early stages, in which macro coverage is provided by LTE, and 5G radio interface access comes from small cells by aggregation to LTE. In other words, 5G is planned to support inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 7 GHz-cmWave, below 7 GHz-cmWave-mmWave).

[0040] A method for implementing data transmission from a passive IoT device to a network node that can be very far away from the passive IoT device is provided. For example, the passive IoT device can operate in a 5G NR infrastructure with a licensed frequency band and over a long range. The method disclosed herein implements a positioning framework that enables one or more passive IoT devices to communicate and locate using a radio access network infrastructure such as a 5G NR infrastructure.

[0041] The active device is configured to perform typical network functions, such as NR functions, and additionally discover one or more passive devices, such as one or more passive terminals or passive IoT devices. The active device can continue its ongoing operation, but the network node is configured to modify the behavior of the active device to additionally perform passive terminal discovery (PTD). The active device is configured to act as a contact point or NR backhaul between the passive device and the network node. Signaling between the passive device and the active device and signaling between the active device and the network node enables the network node to associate one or more active devices with one or more passive devices and populate the IoT infrastructure. The method disclosed herein enables a network node to collect data from a passive device and / or locate a passive device.

[0042] PTD may be performed as a downlink (DL) PTD procedure or an uplink (UL) PTD procedure, for example, if unsatisfactory results are obtained using the first used procedure, the DL PTD procedure or the UL PTD procedure may be activated automatically (i.e., one or the other) or sequentially (i.e., one after the other). If both procedures are used, the measurements of the two procedures may be combined, such as Figure 5 and Figure 6 as described in the context of .

[0043] Figure 2 A passive terminal discovery (PDT) signal 200 is shown by way of example. A PDT signal or PDT reference signal (RS) includes a signature encoded into the signal. Black squares (e.g., squares 250, 251) represent signatures specific to active devices. For example, the signature of a PDT RS may be NR UE specific. The signature may, for example, be defined as a complete set of parameters required to generate the signal. The parameters may include, for example, time, frequency, code or modulation and a repetition pattern.

[0044] For example, a unique DL RS configuration or DL ​​RS signature may be given by one or more of the following parameters:

[0045] -Time dimension: e.g. subframe index, symbol index within a subframe

[0046] - Frequency dimension: e.g. carrier frequency, subcarrier start index, subcarrier stop index, comb pattern

[0047] - Waveform: For example, a) OFDM with QPSK modulation; or b) Zadoff-Chu sequence with length Nzc and root u

[0048] -Repetitive pattern: eg G subframes.

[0049] The PDT signal also includes a sub-signature, which can be associated with a passive device and / or a group of passive devices. The sub-signature can be a passive device-specific configuration of a subset of radio resources used to activate a specific passive device. If the PDT signal does not include a passive device-specific and / or group (i.e., the group to which the passive device belongs) specific sub-signature, the passive device may not be activated. If the PDT signal includes a passive device-specific and / or group-specific sub-signature, it can be activated as described herein. When activated, the passive device is triggered to collect energy and generate a backscattered signal in response. The radio resources may include, for example, time-frequency code resources. Therefore, the identity (ID) of the passive device can be retrieved from the sub-signature of the signal. The sub-signature is encoded into the signal. A sub-signature can be defined as a subset of the complete set of parameters used to generate the original signal. In Figure 2In the example of , subsignature X 260 refers to a subsignature associated with passive device X, and subsignature Y 270 refers to a subsignature associated with passive device Y.

[0050] For example, a subsignature encoded into the signal and corresponding to a passive terminal with identity X (idX) may include one or more of the following parameters:

[0051] -Time dimension: e.g. subframe index, symbol idX index in a subframe

[0052] - Frequency dimension: e.g. carrier frequency, subcarrier start idX index, subcarrier stop idX index, comb pattern idX

[0053] - Waveform: For example, a Zadoff-Chu sequence of length N≠Nzc and root v≠u, such that there is a unique mapping between identity X and the set (N, u, time, frequency dimensions); or b) other amplitude and / or phase modulation. For example, a tag identified by identity X=10011110 can be activated by an OOK signal implementing pattern X.

[0054] The PDT signal may be a DL PTD signal transmitted from a network node to an active device and one or more passive devices. The DL PTD signal may be a repurposed or redefined signal, such as a paging signal, a synchronization signal, a physical random access channel (PRACH) signal, a sidelink (SL) demodulation reference signal (DMRS), or a DL positioning reference signal (PRS). The association between the subsignature and the ID of the passive device is known on the active device side. For example, the association from the serving network node to the active device may be signaled (e.g., explicitly signaled).

[0055] The PDT signal may be a UL PTD signal transmitted from an active device to a network node and one or more passive devices. Like the DL PTD signal, the UL PTD signal may be any active device specific signal or reference signal that has been redefined, for example. For example, the UL PTD signal may be a sounding reference signal (SRS), an SRS for positioning, a UL DMRS, etc.

[0056] For example, let us consider a standard single-purpose DL PTD RS occupying resources physical resource block 1 and physical resource block 2, i.e., {PRB1, PRB2}, which has quadrature phase shift keying (QPSK) symbols for estimating channel state information (CSI). The serving network node (e.g., gNB) can be configured to modify the signal so that it fulfills a dual purpose: PRB1 carries QPSK symbols and PRB2 carries OOK signal X. The OOK implementing mode X is a sub-signature associated with passive device X.

[0057] Then, when the PRB2 signal uniquely activates a passive device (eg, a tag) with identity X, PRB1 and PRB2 can still be used to retrieve CSI. Thus, the PTD signal serves the dual purpose of transmitting CSI and signaling the identity of the passive device.

[0058] A passive device identity can be associated with more than one DL PTD RS, and in this way, a serving network node (e.g., gNB) can simultaneously activate several active devices (e.g., UEs) to detect a passive device with identity X.

[0059] Passive devices may have a group ID and a unique ID. Then, an activator (activation device or network node) generating an activation signal or a PTD signal with a signature embedded in the group ID will activate all passive devices in the group, ie, with the same group ID.

[0060] Figure 3 The signaling between entities is shown by way of example. In this example, a DL PTD procedure is described. A network node 310 (e.g., a serving gNB) transmits 312 a configuration of at least one PTD signal (e.g., a PTD RS) associated with at least one passive device 330. The configuration provides the configuration of the PTD signal and implicitly provides the ID of the passive device. For example, the configuration may be specific to a pair of an active device and a passive device.

[0061] The active device 320 implicitly or explicitly receives information for determining an association between at least one passive device and at least one backscattered PTD signal. Figure 2 As described in the context of , an association may be defined by a sub-signature associated with at least one passive device.

[0062] The network node 310 triggers 314 a DL PTD signal reception by a selected active device 320 (e.g., UE) or a group of active devices randomly distributed in a cell, and configures measurements for a DL PTD signal 316 and a backscattered PTD signal 324 to be reflected by at least one passive device 330. The selection of the active device may be based on, for example, a random selection or past location of the passive device. The configuration provides a configuration for subsequent reception of the DL PTD signal 316. For example, the configuration includes a duration T of detection, a measurement type, etc. In other words, the network node 310 requests the active device 320 to listen for a time period T for the DL PTD signal 316 and the backscattered PTD signal 324.

[0063] The network node 310 transmits DL PTD signals 316 , 318 to at least one active device 320 and at least one passive device 330 .

[0064] The DL PTD signal 316 is used by the active device for its own standard functions, such as synchronization to a cell, acquisition of channel state information (CSI), etc. The active device 320 receives and measures 322 at least one PTD signal according to the configuration.

[0065] The passive device 330 includes an energy harvester. Thus, the passive device is capable of collecting or utilizing energy from various sources such as radio waves or signals, vibrations, and / or light. The passive device 330 utilizes 332 energy from the received PTD signal 318 or sub-signals and generates a backscattered PTD signal. The backscattered PTD signal 324 is obtained by modifying the received PTD signal by the passive device 330 and reflecting the modified signal to be detected by the active device 320 by the passive device 330. For example, the PDT signal can be modified by changing its amplitude, phase, and / or center frequency.

[0066] The active device 320 knows the backscatter PTD signature by knowing the subsignature corresponding to the ID of the passive device 330. Therefore, the active device 320 is able to detect the backscatter PTD signal 324 without any additional signaling cost.

[0067] During time period T, active device 320 listens, detects and measures 322 DL PTD signal 316 from network node 310, and detects and measures 326 backscattered PTD signal 324 from passive device 330. The measurement of the PTD signal may include, for example, received signal strength indicator (RSSI), reference signal received power (RSRP), or any link quality metric.

[0068] The active device 320 reports 328 at least the measured backscatter to the network node 310. In at least some embodiments, the active device 320 reports two measurements to the network node 310. The measurement associated with the PTD signal 316 can relate to the ongoing function of the active device. The measurement associated with the backscatter PTD signal 324 can relate to the passive IoT framework for assisting the network node in collecting data from the passive device and locating the passive device.

[0069] Report 328 may include, for example, a PTD flag and measurement results associated with the identity of the detected passive device.

[0070] The network node 310 evaluates 340 the reported measurements and may determine, based on the measurements, whether to associate at least one active device 320 with at least one detected passive device 330. For example, the network node may receive measurement reports from a plurality of active devices. The network node may be configured to compare the measurements and select the active device that reports the highest signal quality (e.g., the highest received (RX) power). In other words, the active device that has reported a measurement result indicating that the active device hears the passive device loudest may be paired or associated with the passive device. If the network node receives a measurement report from an active device, the network node may determine whether the reported measurement result meets a certain predetermined threshold. If the measurement result does meet the threshold, the network node may generate an association between the active device and the passive device. For example, if the RX power reported by the active device is above a predetermined threshold, the network node may generate an association.

[0071] According to an embodiment, the network node 310 may configure the active device 320 for DL ​​PTD signal reception, but trigger the reception of the backscattered PTD signal for a given instance (e.g., only for a given instance). For example, the DL PTD signals 316, 318 may be transmitted with a period D1, but the active device 320 may be triggered to measure the backscattered PTD signal 324 with a period D2, which is greater than D1. Alternatively, the active device 320 may be triggered to measure the backscattered PTD signal 324 upon an explicit request (e.g., only upon an explicit request). The explicit request from the network node 310 may be included in a dedicated information element, for example, on a DL physical dedicated control channel (PDCCH) that specifies the exact PTD occurrence. If the active device 320 is power limited, or if the active device 320 is performing other operations at the same time (e.g., it is delay sensitive), or if there are more than one active device 320 designated to detect at least one passive device 330, it is beneficial to configure the measurement of the backscattered PTD signal upon explicit request. For example, round-robin scheduling may be used to schedule active devices to perform detection of passive devices.

[0072] Figure 4 Signaling between entities is shown by way of example. In this example, a UL PTD procedure is described. A network node 410 (e.g., a serving gNB) transmits 412 a configuration of at least one PTD signal (e.g., a PTD RS) associated with at least one passive device 430. The configuration provides the configuration of the PTD signal and implicitly provides the ID of the passive device. For example, the configuration may be specific to a pair of an active device and a passive device.

[0073] The active device 420 implicitly or explicitly receives information for determining an association between at least one passive device and at least one backscattered PTD signal. Figure 2 As described in the context of , an association may be defined by a sub-signature associated with at least one passive device.

[0074] The network node 410 triggers 414 a UL PTD signal transmission by an active device 420 (e.g., a random UE) or a group of active devices randomly distributed in a cell, and configures a measurement for a backscattered PTD signal 424 to be reflected by at least one passive device 430. The configuration provides a configuration for a subsequent transmission of the UL PTD signal 416, 418. In addition, the network node 410 provides a configuration for a subsequent reception of the backscattered PTD signal. For example, the configuration includes a duration T of detection, a measurement type, etc. In other words, the network node 410 configures the active device 420 to transmit the UL PTD signal 416, 418 for a duration T1, followed by a listening gap of duration T2 to hear the potential backscattered PTD signal 424 reflected by at least one passive device 430.

[0075] The time period T2 may be proportional to the total round trip time it can take for the signal to travel the maximum distance D. Then, T2 = 2D / c, where c is the speed of the signal, which is approximately the speed of light in the Earth's atmosphere. For example, the maximum distance D may depend on the transmission power and noise level of the receiver detecting the signal.

[0076] The active device 420 transmits UL PTD signals 416 , 418 to the network node 410 and at least one passive device 430 .

[0077] The passive device 430 includes an energy harvester. Thus, the passive device is capable of collecting or utilizing energy from various sources such as radio waves or signals, vibrations, and light. The passive device 430 utilizes 432 energy from the received PTD signal 318 or sub-signal, and generates a backscattered PTD signal if the passive device determines that the PTD signal is intended for it. The determination may be based on a passive device specific sub-signature. The backscattered PTD signal 424 is generated by modifying the received PTD signal by the passive device 430 and reflecting the modified signal by the passive device 430 to be detected by the active device 420. For example, the PDT signal may be modified by changing its amplitude, phase, and / or center frequency.

[0078] During a subsequent time period T2, the active device 420 listens for and attempts to detect at least one backscattered PTD signal from at least one passive device 430. The active device attempts to detect those backscattered PTD signals whose patterns match corresponding subsignatures of the original UL PTD signal 418 generated and transmitted by the active device.

[0079] The active device 420 detects at least one backscatter PTD signal 424 and measures 426 the detected backscatter PTD signal(s). The measurements of the backscatter PTD signal may include, for example, a received signal strength indicator (RSSI), a reference signal received power (RSRP), or any link quality metric.

[0080] The active device 420 reports 428 at least the measured backscatter to the network node 410. The report 428 may include, for example, a PTD flag and the measurement results associated with the identity of the detected passive device.

[0081] The network node 410 evaluates 440 the reported measurements and may determine based on the measurements whether to associate at least one active device 420 with at least one detected passive device 430. For example, the network node may receive measurement reports from multiple active devices. The network node may be configured to compare the measurements and select the active device that reports the highest signal quality (e.g., the highest receive (RX) power). In other words, the active device that has reported a measurement result indicating that the active device hears the passive device loudest may be paired or associated with the passive device. If the network node receives a measurement report from an active device, the network node may determine whether the reported measurement result meets a predetermined threshold. If the measurement result does meet the threshold, the network node may generate an association between the active device and the passive device. For example, if the RX power reported by the active device is above a predetermined threshold, the network node may generate an association.

[0082] Figure 5 The signaling between the entities is shown by way of example. The network node 510 may interleave the DL PTD process (e.g. Figure 3 ) and the UL PTD procedure (as described in the context of Figure 4 For example, the network node 510 may first configure the active device 520 for the DL PTD process 540. Figure 3 As described in the context of , the active device 520 may perform a DL PTD process according to the configuration.

[0083] The network node 510 may evaluate 542 the measurements reported by the active device 520. If the association between the active device 520 and the passive device 530 fails, the network node 510 may trigger 544 the UL PTD procedure. For example, the association may fail if no active device has detected the passive device signal, or if the reported RX power level is below a predetermined threshold.

[0084] As in Figure 4As described in the context of , the active device 520 may perform the UL PTD procedure 546 according to the configuration from the network node 510 .

[0085] If the DL PTD process fails due to not detecting any passive devices, the measurements of the UL PTD process may be evaluated without considering the DL PTD process. If the RS power level reported in the DL PTD process is too low, the network node 510 may then combine 548 the measurements reported in conjunction with the DL PTD process and the UL PTD process. The network node 510 may evaluate the measurements from both processes and determine whether to generate an association between the active device 520 and the at least one passive device 530.

[0086] The network node 510 may be configured to compare the measurements reported by the active devices and based on the comparison decide whether to generate 550 an association. For example, the network node may compare the RX power levels reported by the active devices.

[0087] exist Figure 5 In the example of , after the failed association is generated from the DL PTD process, the DL PTD process 540 is performed first and the UL PTD process 546 is performed. According to an embodiment, the UL PTD process may be performed first. If the association fails after the UL PTD process fails, the network node 510 may trigger the DL PTD process.

[0088] Figure 6 The signaling between the entities is shown by way of example. The network node 610 may configure the active device 620 to perform 640 a DL PTD procedure (e.g., Figure 3 ), or the UL PTD procedure (as described in the context of Figure 4 ), or two processes (as described in the context of Figure 5 described in the context of ).

[0089] The network node 610 may evaluate measurements from the DL PTD procedure or the UL PTD procedure or both procedures.

[0090] The network node 610 may generate 644 an association between at least one active device 620 and at least one passive device 630 .

[0091] The network node 610 may transmit 646 information about an association between at least one active device 620 and at least one passive device 630 to a location management function (LMF) 600 for locating at least one passive device. For example, the information about the association may include a list of "active device-passive device" pairs, such as "UE-passive IoT ID" pairs. The LMF 600 may trigger a passive device positioning 648 session. The LMF 600 may configure a positioning session 648 using the results of the PTD procedure(s) between the network node 610, the at least one active device 620, and the at least one passive device 630. The result of the PTD procedure(s) is an association between the active device and the passive device.

[0092] Figure 7 The flowchart of method 700 is shown by way of example. The stages of method 700 may be performed by an active device or an active radio or an active radio device (e.g., a UE, an RSU, or a small gNB), or by a control device configured to control its functions when installed therein. The active device may be, for example, a device configured to perform at least the steps of method 700. Figure 3 , Figure 4 , Figure 5 or Figure 6 The method 700 includes receiving 710, by the active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device from a network node. The method 700 includes transmitting 720 at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration. The method 700 includes measuring 730 at least one backscattered passive terminal discovery signal from at least one passive radio device. The method 700 includes reporting 740 at least the measured backscatter to the network node.

[0093] Figure 8 The flowchart of method 800 is shown by way of example. The stages of method 800 may be performed by a network node (e.g., a gNB), or by a control device configured to control its functions when installed therein. The network node may be, for example, a controller configured to perform at least the steps of method 800. Figure 3 , Figure 4 , Figure 5 or Figure 6The method 800 comprises transmitting 810, by the network node, to at least one active radio device, configuration of at least one passive terminal discovery signal associated with at least one passive radio device. The method 800 comprises triggering 820 reception and / or transmission of at least one passive terminal discovery signal. The method 800 comprises receiving 830 from at least one active radio device at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that has been detected by the at least one active radio device. The method 800 comprises determining 840 whether to associate the at least one active radio device with the at least one detected passive radio device based on the measured backscatter received from the at least one active radio device.

[0094] The method as disclosed herein enables data transmission from a passive device to a network node. The method disclosed herein enables locating a passive device by using an optimal set of active devices. The optimal set of active devices includes at least one active device that has been associated with at least one passive device by a network node based on a measured backscattered passive terminal discovery signal reflected by at least one passive device. The PTD signal has the dual purpose of being used as a reference signal, such as for transmitting CSI or as a positioning reference signal (PRS), and includes a subsignature associated with a passive device, so that the active device can detect the passive device, which backscatters the PTD signal.

[0095] The DL PTD signal has a first purpose with respect to active devices and a second purpose with respect to passive devices. The first purpose includes, for example, at least one of the following: paging, synchronization, initial access, demodulation purposes, and positioning. For the purpose of paging, the reference signal is a paging signal. For the purpose of synchronization, the reference signal is a synchronization signal. For the purpose of initial access, the reference signal is a physical random access channel (PRACH) signal. For the purpose of demodulation, the reference signal is a downlink demodulation reference signal (DL DMRS). For the purpose of positioning, the reference signal is a downlink positioning reference signal (DL PRS).

[0096] The UL PTD signal has a first purpose for active devices and a second purpose for passive devices. The first purpose includes, for example, at least one of the following: uplink channel determination, demodulation, and positioning. For the purpose of uplink channel determination, the reference signal is a sounding reference signal (SRS). For the purpose of demodulation, the reference signal is a downlink demodulation reference signal (DMRS). For the purpose of positioning, the reference signal is an SRS for positioning.

[0097] The second purpose is the same for both DL PTD signals and UL PTD signals.The second purpose with respect to passive devices includes a sub-signature associated with the passive device, enabling the active device to detect the passive device, which backscatters the PTD signal.

[0098] Fig. 9 A block diagram of an apparatus capable of performing at least one (or more) of the methods disclosed herein is shown by way of example. Shown is a device 900, which may include, for example, a mobile communication device, such as an active device, for example, Figure 3 , Figure 4 , Figure 5 or Figure 6 Alternatively, the device 900 may include a network node, for example, Figure 3 , Figure 4 , Figure 5 or Figure 6 The network nodes 310, 410, 510, 610 of the present invention are shown in Figure 9. Included in the device 900 is a processor 910, which may include, for example, a single-core or multi-core processor, wherein the single-core processor includes one processing core and the multi-core processor includes more than one processing core. The processor 910 may generally include a control device. The processor 910 may include more than one processor. The processor 910 may be a control device. The processing core may include, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Steamroller processing core designed by Advanced Micro Devices Corporation. The processor 910 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. The processor 910 may include at least one application-specific integrated circuit ASIC. The processor 910 may include at least one field programmable gate array FPGA. The processor 910 may be a component for executing the method steps in the device 900. The processor 910 may be configured at least in part by computer instructions to perform actions.

[0099] The processor may include a circuit, or be constituted as one or more circuits, which are configured to perform the stages of the method according to the example embodiments described herein. As used in this application, the term "circuit" may refer to one or more or all of the following: (a) hardware circuit implementations only, such as implementations in analog and / or digital circuits only, and (b) combinations of hardware circuits and software, such as applicable to: (i) a combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) any portion of (multiple) hardware processors (including (multiple) digital signal processors), software and (multiple) memories with software, which work together to enable an apparatus (such as an active device, e.g., user equipment or network equipment) to perform various functions and (c) (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or portions of (multiple) microprocessors, which require software (e.g., firmware) for operation, but the software may not be present when not required for operation.

[0100] This definition of circuitry applies to all uses of this item in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit used in a mobile device or similar integrated circuit in a server, cellular network device, or other computing or network device.

[0101] The device 900 may include a memory 920. The memory 920 may include a random access memory and / or a permanent memory. The memory 920 may include at least one RAM chip. The memory 920 may include, for example, solid-state, magnetic, optical and / or holographic memory. The memory 920 may be at least partially accessible by the processor 910. The memory 920 may be at least partially included in the processor 910. The memory 920 may be a component for storing information. The memory 920 may include computer instructions that the processor 910 is configured to execute. When computer instructions configured to cause the processor 910 to perform certain actions are stored in the memory 920, and the device 900 as a whole is configured to run under the guidance of the processor 910 using computer instructions from the memory 920, the processor 910 and / or at least one of its processing cores may be considered to be configured to perform the certain actions. The memory 920 may be at least partially external to the device 900 but accessible to the device 900.

[0102] The device 900 may include a transmitter 930. The device 900 may include a receiver 940. The transmitter 930 and the receiver 940 may be configured to transmit and receive information, respectively, according to at least one cellular or non-cellular standard. The transmitter 930 may include more than one transmitter. The receiver 940 may include more than one receiver. The transmitter 930 and / or the receiver 940 may be configured to operate according to standards such as Global System for Mobile Communications, GSM, Wideband Code Division Multiple Access, WCDMA, 5G, Long Term Evolution, LTE, IS-95, Wireless Local Area Network, WLAN, Ethernet, and / or Worldwide Interoperability for Microwave Access, WiMAX, etc.

[0103] The device 900 may include a near field communication NFC transceiver 950. The NFC transceiver 950 may support at least one NFC technology, such as NFC, Bluetooth, Wibree, or similar technology.

[0104] The device 900 may include a user interface UI 960. The UI 960 may include at least one of a display, a keyboard, a touch screen, a vibrator arranged to signal a user by vibrating the device 900, a speaker, and a microphone. The user is able to operate the device 900 via the UI 960, for example to accept an incoming phone call, initiate a phone call or video call, browse the Internet, manage digital files stored in the memory 920 or on a cloud accessible via the transmitter 930 and the receiver 940 or accessible via the NFC transceiver 950, and / or play games.

[0105] The device 900 may include or be arranged to accept a user identity module 970. The user identity module 970 may include, for example, a subscriber identity module, a SIM card installable in the device 900. The user identity module 970 may include information identifying a subscription of a user of the device 900. The user identity module 970 may include cryptographic information that may be used to verify the identity of the user of the device 900 and / or facilitate encryption of communication information and billing of the user of the device 900 for communications implemented via the device 900.

[0106] The processor 910 may be equipped with a transmitter arranged to output information from the processor 910 to other devices included in the device 900 via electrical leads inside the device 900. Such a transmitter may include a serial bus transmitter arranged to output information to the memory 920 for storage therein, for example, via at least one electrical lead. As an alternative to the serial bus, the transmitter may include a parallel bus transmitter. Likewise, the processor 910 may include a receiver arranged to receive information in the processor 910 from other devices included in the device 900 via electrical leads inside the device 900. Such a receiver may include a serial bus receiver arranged to receive information, for example, via at least one electrical lead from a receiver 940 for processing in the processor 910. As an alternative to the serial bus, the receiver may include a parallel bus receiver.

[0107] The processor 910, the memory 920, the transmitter 930, the receiver 940, the NFC transceiver 950, the UI 960 and / or the user identity module 970 can be interconnected in a variety of different ways through electrical leads inside the device 900. For example, each of the above devices can be connected to a main bus inside the device 900 to allow the devices to exchange information. However, as will be understood by those skilled in the art, this is only an example, and various ways of interconnecting at least two of the above devices can be selected depending on the embodiment.

[0108] Fig.10 The flowchart of method 1000 is shown by way of example. The stages of method 1000 may be performed by a passive radio device or a passive device (eg, a tag). The passive device may be, for example, a device configured to perform at least one of method 1000. Figure 3 , Figure 4 , Figure 5 or Figure 6 The method 1000 includes receiving 1010 at least one passive terminal discovery signal by a passive radio device. The method includes harvesting 1020 energy from at least the received passive terminal discovery signal using an energy harvester. The method 1000 includes: if the received passive terminal discovery signal includes a subsignature associated with the device, generating 1030 at least one backscattered passive terminal discovery signal based on at least the harvested energy; and if the received passive terminal discovery signal does not include a subsignature associated with the device, avoiding generating at least one backscattered passive terminal discovery signal. The method 1000 includes: if at least one backscattered passive terminal discovery signal is generated, transmitting 1040 at least one backscattered passive terminal discovery signal.

Claims

1. An apparatus comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: receiving, from a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from the at least one passive radio device; and At least the measured backscatter is reported to the network node.

2. The apparatus according to claim 1, being caused to perform: Information for determining an association between the at least one passive radio device and the at least one backscattered passive terminal discovery signal is received.

3. The apparatus of claim 2, wherein the association is defined by a sub-signature associated with the at least one passive radio device, wherein the sub-signature is a passive radio device-specific configuration of a subset of radio resources.

4. The apparatus of any preceding claim, wherein the configuration of at least one passive terminal discovery signal comprises: Configuration for transmission of at least one passive terminal discovery signal.

5. The apparatus according to claim 4, being caused to perform: At least one backscattered passive terminal discovery signal from the at least one passive radio device is detected based on a pattern of the signal corresponding to a subsignature associated with the transmitted at least one passive terminal discovery signal.

6. The apparatus of any preceding claim, wherein the configuration of at least one passive terminal discovery signal comprises: Configuration for reception of at least one passive terminal discovery signal.

7. The apparatus according to claim 6, being caused to perform: measuring, in accordance with the configuration, the at least one passive terminal discovery signal received from the network node, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the apparatus and a second purpose with respect to the passive radio device; and The measurement result is transmitted to the network node.

8. The apparatus according to claim 7, wherein the first purpose comprises at least one of: paging, synchronization, initial access, demodulation, and positioning.

9. The device according to any one of claims 3 to 8, wherein The sub-signature is based on at least one of the following: a time dimension, a frequency dimension or a waveform of the passive terminal discovery signal.

10. The device according to any one of claims 3 to 9, wherein The sub-signature is unique to the passive radio device.

11. The device according to any one of claims 3 to 9, wherein The sub-signature is unique to a group of passive radio devices.

12. An apparatus according to any preceding claim, caused to perform: A request to measure the at least one backscatter passive terminal discovery signal is received.

13. An apparatus according to any preceding claim, caused to perform: The at least one passive terminal discovery signal is transmitted according to the configuration, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the apparatus and a second purpose with respect to the at least one passive radio device.

14. The apparatus of claim 13, wherein the first purpose comprises at least one of: uplink channel determination, demodulation, and positioning.

15. An apparatus comprising at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: transmitting, to at least one active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; triggering reception and / or transmission of the at least one passive terminal discovery signal; receiving, from the at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that the at least one active radio device has detected; as well as Based on the measured backscatter received from the at least one active radio device, it is determined whether to associate the at least one active radio device with at least one detected passive radio device.

16. The apparatus according to claim 15, being caused to perform: Information for determining an association between the at least one passive radio device and the at least one backscattered passive terminal discovery signal is transmitted to the at least one active radio device.

17. The apparatus of claim 16, wherein the association is defined by a sub-signature associated with the at least one passive radio device, wherein the sub-signature is a passive radio device specific configuration of a subset of radio resources.

18. The device according to any one of claims 15 to 17, wherein The configuration of at least one passive terminal discovery signal comprises: configuration for transmission of at least one passive terminal discovery signal; and the apparatus is caused to perform: At least one passive terminal discovery signal is received from the at least one active radio device.

19. The device according to any one of claims 15 to 18, wherein The configuration of at least one passive terminal discovery signal comprises: Configuration for reception of at least one passive terminal discovery signal.

20. The apparatus of claim 19, being caused to perform: transmitting a passive terminal discovery signal to the at least one active radio device and the at least one passive radio device, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the at least one active radio device and a second purpose with respect to the at least one passive radio device; and Measurement results associated with at least one transmitted passive terminal discovery signal are received from the at least one active radio device.

21. The apparatus of claim 20, wherein the first purpose comprises at least one of: paging, synchronization, initial access, demodulation purpose, and positioning.

22. An apparatus according to claims 15 to 21, caused to perform: In response to determining that the measured backscatter from the at least one active radio device satisfies a predetermined threshold, an association between the at least one active radio device and at least one detected passive radio device is generated.

23. The apparatus of claim 22, being caused to perform: Information about the association between the at least one active radio device and at least one detected passive radio device is transmitted to a location management function for locating the at least one passive radio device.

24. A method comprising: receiving, by the active radio device, from a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from the at least one passive radio device; as well as At least the measured backscatter is reported to the network node.

25. The method according to claim 24, comprising: Information for determining an association between the at least one passive radio device and the at least one backscattered passive terminal discovery signal is received.

26. The method of claim 25, wherein the association is defined by a sub-signature associated with the at least one passive radio device, wherein the sub-signature is a passive radio device specific configuration of a subset of radio resources.

27. The method according to any one of claims 24 to 26, wherein the configuration of at least one passive terminal discovery signal comprises: Configuration for transmission of at least one passive terminal discovery signal.

28. The method according to claim 27, comprising: At least one backscattered passive terminal discovery signal from the at least one passive radio device is detected based on a pattern of signals corresponding to a subsignature associated with the transmitted at least one passive terminal discovery signal.

29. The method according to any one of claims 24 to 28, wherein the configuration of at least one passive terminal discovery signal comprises: Configuration for reception of at least one passive terminal discovery signal.

30. The method according to claim 29, comprising: measuring, in accordance with the configuration, the at least one passive terminal discovery signal received from the network node, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the active device and a second purpose with respect to the passive radio device; as well as The measurement result is transmitted to the network node.

31. The method of claim 30, wherein the first purpose comprises at least one of: paging, synchronization, initial access, demodulation, and positioning.

32. The method according to any one of claims 24 to 32, wherein The sub-signature is based on at least one of the following: a time dimension, a frequency dimension or a waveform of the passive terminal discovery signal.

33. The method according to any one of claims 24 to 32, wherein The sub-signature is unique to the passive radio device.

34. The method according to any one of claims 24 to 32, wherein The sub-signature is unique to a group of passive radio devices.

35. A method according to any one of claims 24 to 34, comprising: A request to measure the at least one backscatter passive terminal discovery signal is received.

36. A method according to any one of claims 24 to 35, comprising: The at least one passive terminal discovery signal is transmitted according to the configuration, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the apparatus and a second purpose with respect to the passive radio device.

37. The method of claim 36, wherein the first purpose comprises at least one of: uplink channel determination, demodulation, and positioning.

38. A method comprising: transmitting, by a network node, to at least one active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; triggering reception and / or transmission of the at least one passive terminal discovery signal; receiving, from the at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that the at least one active radio device has detected; as well as Based on the measured backscatter received from the at least one active radio device, it is determined whether to associate the at least one active radio device with at least one detected passive radio device.

39. The method according to claim 38, comprising: Information for determining an association between the at least one passive radio device and the at least one backscattered passive terminal discovery signal is transmitted to the at least one active radio device.

40. The method of claim 39, wherein the association is defined by a sub-signature associated with the at least one passive radio, wherein the sub-signature is a passive radio specific configuration of a subset of radio resources.

41. The method according to any one of claims 38 to 40, wherein The configuration of at least one passive terminal discovery signal comprises: Configuration for transmission of at least one passive terminal discovery signal; and the method comprises: At least one passive terminal discovery signal is received from the at least one active radio device.

42. The method according to any one of claims 38 to 41, wherein The configuration of at least one passive terminal discovery signal comprises: Configuration for reception of at least one passive terminal discovery signal.

43. The method according to claim 42, comprising: transmitting a passive terminal discovery signal to the at least one active radio device and the at least one passive radio device, wherein the at least one passive terminal discovery signal is a dual purpose signal having a first purpose with respect to the at least one active radio device and a second purpose with respect to the at least one passive radio device; as well as Measurement results associated with at least one transmitted passive terminal discovery signal are received from the at least one active radio device.

44. The method of claim 43, wherein the first purpose comprises at least one of: paging, synchronization, initial access, demodulation purpose, and positioning.

45. The method of claims 38 to 44, comprising: In response to determining that the measured backscatter from the at least one active radio device satisfies a predetermined threshold, an association between the at least one active radio device and at least one detected passive radio device is generated.

46. ​​The method of claim 45, comprising: Information about the association between the at least one active radio device and at least one detected passive radio device is transmitted to a location management function for locating the at least one passive radio device.

47. An apparatus comprising means for performing: receiving, from a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from the at least one passive radio device; and At least the measured backscatter is reported to the network node.

48. Apparatus according to claim 47, comprising means for performing a method according to any one of claims 25 to 37.

49. An apparatus comprising means for performing: transmitting, to at least one active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; triggering reception and / or transmission of the at least one passive terminal discovery signal; receiving, from the at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that the at least one active radio device has detected; as well as Based on the measured backscatter received from the at least one active radio device, it is determined whether to associate the at least one active radio device with at least one of the detected passive radio devices.

50. Apparatus according to claim 49, comprising means for performing a method according to any one of claims 39 to 46.

51. The device according to any one of claims 47 to 50, wherein The means comprises at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause said execution of the apparatus.

52. A computer readable medium comprising program instructions which, when executed by at least one processor, cause an apparatus to at least perform: receiving, from a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from the at least one passive radio device; and At least the measured backscatter is reported to the network node.

53. The computer readable medium of claim 52, comprising program instructions which, when executed by at least one processor, cause an apparatus to perform at least the method of any one of claims 25 to 37.

54. A computer readable medium comprising program instructions which, when executed by at least one processor, cause an apparatus to at least perform: transmitting, to at least one active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; triggering reception and / or transmission of the at least one passive terminal discovery signal; receiving, from the at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that the at least one active radio device has detected; as well as Based on the measured backscatter received from the at least one active radio device, it is determined whether to associate the at least one active radio device with at least one detected passive radio device.

55. The computer readable medium of claim 54, comprising program instructions which, when executed by at least one processor, cause an apparatus to perform at least the method of any one of claims 39 to 46.

56. A computer program configured, when executed on a device, to cause the device to perform a method comprising: receiving, from a network node, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; transmitting at least one passive terminal discovery signal according to the configuration; and / or receiving at least one passive terminal discovery signal according to the configuration; measuring at least one backscattered passive terminal discovery signal from the at least one passive radio device; as well as At least the measured backscatter is reported to the network node.

57. The computer program of claim 56, configured to cause the apparatus to at least perform the method of any one of claims 25 to 37.

58. A computer program configured, when executed on a device, to cause the device to perform a method comprising: transmitting, to at least one active radio device, a configuration of at least one passive terminal discovery signal associated with at least one passive radio device; triggering reception and / or transmission of the at least one passive terminal discovery signal; receiving, from the at least one active radio device, at least measured backscatter of at least one backscattered passive terminal discovery signal from at least one passive radio device that the at least one active radio device has detected; as well as Based on the measured backscatter received from the at least one active radio device, it is determined whether to associate the at least one active radio device with at least one detected passive radio device.

59. The computer program according to claim 58, configured to cause the apparatus to perform at least the method according to any one of claims 39 to 46.

60. An apparatus comprising: Energy harvester; at least one processor and at least one memory, the at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: receiving at least one passive terminal discovery signal; harvesting energy from at least the received passive terminal discovery signal using the energy harvester; If the received passive terminal discovery signal includes a subsignature associated with the apparatus, generating at least one backscattered passive terminal discovery signal based at least on the harvested energy; and refraining from generating the at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include the subsignature associated with the apparatus; and If the at least one backscatter passive terminal discovery signal is generated, the at least one backscatter passive terminal discovery signal is transmitted.

61. A method comprising: receiving, by a passive radio device, at least one passive terminal discovery signal; harvesting energy from at least the received passive terminal discovery signal using an energy harvester; If the received passive terminal discovery signal includes a subsignature associated with the apparatus, generating at least one backscattered passive terminal discovery signal based at least on the harvested energy; and refraining from generating the at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include the subsignature associated with the apparatus; and If the at least one backscatter passive terminal discovery signal is generated, the at least one backscatter passive terminal discovery signal is transmitted.

62. An apparatus comprising components for: receiving at least one passive terminal discovery signal; harvesting energy from at least the received passive terminal discovery signal using an energy harvester; If the received passive terminal discovery signal includes a subsignature associated with the apparatus, generating at least one backscattered passive terminal discovery signal based at least on the harvested energy; and refraining from generating the at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include the subsignature associated with the apparatus; and If the at least one backscatter passive terminal discovery signal is generated, the at least one backscatter passive terminal discovery signal is transmitted.

63. A computer program configured, when executed on a device, to cause the device to perform a method comprising: receiving at least one passive terminal discovery signal; collecting energy from at least the received passive terminal discovery signal; If the received passive terminal discovery signal includes a subsignature associated with the apparatus, generating at least one backscattered passive terminal discovery signal based at least on the harvested energy; and refraining from generating the at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include the subsignature associated with the apparatus; and If the at least one backscatter passive terminal discovery signal is generated, the at least one backscatter passive terminal discovery signal is transmitted.

64. A computer program configured, when executed on a device, to cause the device to perform a method comprising: receiving at least one passive terminal discovery signal; collecting energy from at least the received passive terminal discovery signal; If the received passive terminal discovery signal includes a subsignature associated with the apparatus, generating at least one backscattered passive terminal discovery signal based at least on the harvested energy; and refraining from generating the at least one backscattered passive terminal discovery signal if the received passive terminal discovery signal does not include the subsignature associated with the apparatus; and If the at least one backscatter passive terminal discovery signal is generated, the at least one backscatter passive terminal discovery signal is transmitted.

Images