Methods and devices for facilitating network registration of a low power device

Abstract

A method carried out in a low power device, LPD, upon registering to a wireless network, the method comprising: broadcasting (705) a first uplink, UL, message indicative of a registration request, comprising an ID of the LPD in the wireless network; receiving (710), from at least one communication node, an acknowledgement comprising a node ID of a communication node which received the first UL message; determining (715) initial network topology based on the acknowledgement.

Description

[0001] METHODS AND DEVICES FOR FACILITATING NETWORK REGISTRATION OF

[0002] A LOW POWER DEVICE

[0003] Technical field

[0004] This disclosure is related to wireless communication between a wireless device and a wireless network. Specifically, solutions are provided for triggering network registration of wireless devices, in particular low power devices such as passive wireless devices configured to transmit responsive to receiving radio-frequency energy.

[0005] Background

[0006] Various protocols and technical requirements for wireless communication have been standardized under supervision of inter alia the 3rd Generation Partnership Project (3GPP). Improvement and further development are continuously carried out, and new or amended functions and features are thus implemented in successive releases of the technical specifications providing the framework for wireless communication.

[0007] Wireless communication may in various scenarios be carried out between a wireless network and a wireless device. The wireless network typically comprises an access network including a plurality of access nodes, which historically have been referred to as base stations. In a 5G radio access network such a base station may be referred to as a gNB. Each access node may be configured to serve one or more cells of a cellular wireless network. A variety of different types of wireless devices may be configured to communicate with the access network, and such wireless devices are generally referred to as User Equipment (UE). Communication which involves transmission from the UE and reception in the wireless network is generally referred to as Uplink (UL) communication, whereas communication which involves transmission from the wireless network and reception in the UE is generally referred to as Downlink (DL) communication.

[0008] Every UE needs to be powered in some way to be able to communicate with the wireless network. Regardless of the capability of the UE, energy conservation is a relevant factor to consider. One clear development that can be identified in the evolving character of the specifications which provide regulations and guidelines for wireless communication, is the implementation of a larger variety of types of UEs, including UEs of lower complexity, as well as related regulations which may be simplified or relaxed with regard to communication configuration, associated with such lower complexity UEs. This can be seen as part of an evolution towards an Internet of Things (loT) context, where a vast amount of connectable UEs and UE types are conceivable, some of which may be configured only for simple communications tasks, such as to occasionally report a measured value of a certain parameter, such as radio signal measurement, positioning, and sensor output. One of the considered UE type is ambient loT device. According to 3GPP TR 22.840 version 2.2.0 (2023-12), an Ambient Internet of Things (Ambient loT) device is an ambient power-enabled Internet of Things device is an loT device powered by energy harvesting, being either battery-less or with limited energy storage capability (e.g., using a capacitor).

[0009] For at least some types, such UEs (e.g., ambient loT device) may be expected to be able to operate for very long periods of time without needing a battery recharge or replacement, in particular for UE types being configured for long periods of inactivity between scarce and short communication instances. However, signaling according to legacy procedures for accomplishing network registration may in many cases be challenging or even impossible for such types of UEs.

[0010] Summary

[0011] In view of the foregoing, it is an objective to present a solution for handling UEs in a wireless network, which solution is configured to facilitate network registration of UEs operating with power and or processing constraints. An aspect of this objective is to provide a solution which facilitates registration of passive type UEs, such as ambient loT device, which can be configured to transmit in UL only in response to DL reception.

[0012] The proposed solution is set out in the independent claims, whereas various examples thereof are set out in the dependent claims and in the following detailed description. Brief description the drawings

[0013] Fig. 1 schematically illustrates an implementation of a wireless communication system, in which a UE communicates with a wireless network by radio communication with a communication node.

[0014] Fig. 2 schematically illustrates a communication node in the form of an access node of the wireless network, configured to operate in accordance with the proposed solution as laid out herein.

[0015] Fig. 3A schematically illustrates general features of a UE configured to operate with the wireless network according to various examples.

[0016] Fig. 3B illustrates an example of a particular kind of passive type UE according to Fig. 3A, configured to operate as a low power device by harvesting radio-frequency energy from a received wireless signal, to process and transmit in the uplink by reflecting the bearer.

[0017] Fig. 4 provides various examples of network topology, which may be determined and indicated in examples of the proposed solution.

[0018] Fig. 5A illustrates a signaling diagram associated with a network-based, or network-centric, configuration of the proposed solution.

[0019] Fig. 5B illustrates a signaling diagram associated with a device-based, or devicecentric, configuration of the proposed solution.

[0020] Fig. 6 schematically illustrates resource configuration for at least UE transmission, useful in various examples of the proposed solution.

[0021] Fig. 7 provides a flowchart of a method carried out in a low power device according to various examples of the proposed solution.

[0022] Fig. 8A provides a flowchart of a method carried out in an access node according to various network-based examples of the proposed solution.

[0023] Fig. 8B provides a flowchart of a method carried out in an access node according to various device-based examples of the proposed solution.

[0024] Fig. 9 provides a flowchart of a method carried out in a wireless communication node acting as an assisting node according to various network-based examples of the proposed solution. Detailed description

[0025] In the following description, for the purposes of explanation and not limitation, details are set forth herein related to various examples. However, it will be apparent to those skilled in the art that the present invention may be practiced in other examples that depart from these specific details. In some instances, detailed descriptions of well- known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. The functions of the various elements including functional blocks, including but not limited to those labeled or described as “computer”, “processor” or “controller”, may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and / or computer-implemented and are thus machine-implemented. In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) (ASIC), and (where appropriate) state machines capable of performing such functions. In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term “processor” or “controller” shall also be construed to refer to other hardware capable of performing such functions and / or executing software, such as the example hardware recited above.

[0026] 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. The terms “receive” or “receiving” data or information shall be understood as “detecting, from a received signal”.

[0027] Fig. 1 illustrates a high-level perspective of operation of a wireless system, wherein a wireless communication network 100, denoted wireless network 100 for short herein, is configured to operate with various wireless devices. The wireless network 100 may be a radio communication network 100, configured to operate under the provisions specified by 3GPP, according to various examples. The wireless network 100 may comprise a core network (CN) 110, connectable to an external network 130 such as the Internet. The core network may comprise a plurality of core network nodes, which realize logical functions. For the example of a 5G system, as illustrated, this may inter alia include the Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF), a Network Exposure Function (NEF), Location Management Function (LMF), and an Application Function (AF), all of which are legacy functions of the 5G system.

[0028] The core network 110 is connected to at least one access network 120, e.g. Radio Access Network (RAN), comprising one or more base stations or access nodes, of which one access node 121 is illustrated. The access node 121 is a radio node configured for wireless communication on a physical channel 140, 142 with various UEs, of which UE 10 is shown. In some examples, node 20 may be another UE. In accordance with various legacy procedures, UE 10 may further be configured to communicate on a physical channel 140 directly with the wireless network 100, or indirectly with the wireless network 100 via physical channels 141, 142 and utilizing the node UE 20. The physical channels may be used for setting up one or more logical channels.

[0029] Before discussing further details and aspects of the proposed method, functional elements for examples of the entities involved in carrying out the proposed solution will be briefly discussed with reference to the drawings.

[0030] Fig. 2 schematically illustrates a communication node in the form of the access node 121 of the wireless network 100 as presented herein, configured for carrying out various method steps as outlined. In various examples, the access node 121 is a radio base station for operation in the radio communication network 100, to serve one or more radio UEs, such as UE 10 and node 20.

[0031] The access node 121 may comprise a wireless transceiver 213, such as a radio transceiver for communicating with other entities of the radio communication network 100, such as the UE 10. The transceiver 213 may thus include a radio receiver and transmitter for communicating through at least an air interface. The wireless transceiver may, in the context of the proposed solution, be configured to support registration of and communication with low-power devices, such as ambient loT or zero-energy device, as described herein.

[0032] The access node 121 may further comprise, or be connected to, an antenna 214 which may comprise a plurality of antennas (antenna elements) in an array configuration. The antenna array 214 is connected to the transceiver 213.

[0033] The access node 121 further comprises logic circuitry 210 configured to control the access node 121 to communicate with the UEs via the radio transceiver 213 on a physical channel. The logic circuitry 210 may be configured for resource allocation and may realize a scheduler for scheduling communication of a data.

[0034] The logic circuitry 210 may include a processing device 211, including one or multiple processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. Processing device 211 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an applicationspecific integrated circuit (ASIC), etc.). The processing device 211 may be configured to perform one or multiple operations based on an operating system and / or various applications or programs.

[0035] The logic circuitry 210 may further include memory storage 212, which may include one or multiple memories and / or one or multiple other types of storage mediums. For example, memory storage 212 may include a random access memory (RAM), a dynamic random access memory (DRAM), a cache, a read only memory (ROM), a programmable read only memory (PROM), flash memory, and / or some other type of memory. Memory storage 212 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, a solid state disk, etc.). The memory storage 212 is configured for holding computer program code, which may be executed by the processing device 211, wherein the logic 210 is configured to control the access node 121 to carry out any of the method steps as provided herein. Software defined by said computer program code may include an application or a program that provides a function and / or a process. The software may include device firmware, an operating system (OS), or a variety of applications that may execute in the logic 210.

[0036] The access node 121 may further comprise an interface 215, configured for communication with the core network 110.

[0037] Fig. 3A schematically illustrates an example of a UE 10 configured to communicate with the wireless network 100 as presented herein and configured for carrying out various method steps as outlined. In this context, the UE 10 may in various examples be configured as a Low Power Device (LPD), as will be discussed below. In some examples, the UE, or LPD, 10 is configured to operate as an Ambient loT device or zero-energy device. The drawing shows some relevant elements or functions of the UE 10. The UE 10 may however include other features and elements than those shown in the drawing or described herein, such as a casing, a user interface, sensors, etc., but these are left out for the sake of simplicity. In cases where the node 20 is another UE, it may also be configured in accordance with Fig. 3A.

[0038] The UE 10 comprises a radio transceiver 313, also referred to herein as modem 313, for communicating in one or more frequency bands with other entities of the radio communication network 100, such as with the access node 121 or with another UE over an air interface, such as by Sidelink communication or by using a simplified or a new protocol suitable for ambient loT. The transceiver 313 may thus include a receiver chain (Rx) and a transmitter chain (Tx), for communicating through at least an air interface, referred to as Uu in 3GPP. The transceiver 313 may be or comprise a modem configured to encode, transmit, receive and decode data, conveyed using radio waves. In some examples, the transceiver may be configured to operate on a very low- complexity modulation, such as On-Off Keying (OOK) modulation, binary frequency shift keying (BFSK), and binary phase shift keying (BPSK), and may use backscattering communication, as described with reference to Fig. 3B.

[0039] The UE 10 may further comprise an antenna system 314, which may include one or more antennas, antenna ports or antenna arrays. The antenna system 314 is connected to the transceiver 313.

[0040] The UE 10 further comprises logic circuitry 310 configured to control data and signal communication via the radio transceiver on a physical channel to a serving access node of the wireless network 100, and data encoding and decoding. The logic circuitry is further configured to control the UE to carry out any of the steps associated with the proposed solution as outlined herein.

[0041] The logic circuitry 310 may include a processing device 311, including one or multiple processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. The processing device 311 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an applicationspecific integrated circuit (ASIC), etc.). The processing device 311 may be configured to perform one or multiple operations based on an operating system and / or various applications or programs.

[0042] The logic circuitry 310 may further include memory storage 312, which may include one or multiple memories and / or one or multiple other types of storage mediums. For example, the memory storage 312 may include a random access memory (RAM), a dynamic random access memory (DRAM), a cache, a read only memory (ROM), a programmable read only memory (PROM), flash memory, and / or some other type of memory. The memory storage 312 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, a solid state disk, etc.). The memory storage 312 is configured for holding computer program code, which may be executed by the processing device 311, wherein the logic circuitry 310 is configured to control the UE 10 to carry out any of the method steps as provided herein. Software defined by said computer program code may include an application or a program that provides a function and / or a process. The software may include device firmware, an operating system (OS), or a variety of applications that may execute in the logic circuitry 310.

[0043] The UE 10 further comprises a power supply 315 that provides energy to the other components of the UE 10. In some examples, the power supply 315 may comprise a battery. The battery 315 may be non-replaceable, and even non-chargeable, in various embodiment of low complexity UE types. In yet another example, the power supply 315 is configured to harvest incoming radio frequency (RF) energy or other energy resources for instance light, kinetic energy, etc, which is used to power the other components of the UE 10, so as to enable certain processing and UL transmission.

[0044] Fig. 3B provides a schematic overview of such an example, usable in the UE 10, wherein the UE 10 may be configured as an LPD, such as an ultra-low power loT device, that includes passive or semi-passive circuitry, and that harvests energy to perform UL transmission. The UE 10 may thus be configured to employ so-called backscatter communication, similar to RFID tags. B ackscattering is when the transceiver 313 in the UE 10 uses the DL carrier wave, noted as RF in the drawing, for both energy harvesting and using it for UL transmission by reflecting the carrier back after modulating the carrier with the UL data. Same reference numerals as used in Fig. 3A are used in Fig. 3B, although the functional elements are differently realized. In this context, and using the logical representation provided in Fig. 3B, the power supply 315 may comprise a power harvesting circuit 316, connected to the antenna 314, a power management module and a capacitor, such as a supercapacitor. The transceiver 313 may comprise a communication control module, which is powered by the power management module. The communication control module may be connected to a demodulator for demodulating an incoming RF signal, and to a modulator for subsequently modulating an outgoing, “reflected”, RF signal. The logic circuitry 310, comprising the processor 311 and memory 312, is likewise energized by the power management module and connected to control operation of the at least the transceiver 313.

[0045] There are also other types of UEs, including other types of RFID device types, having high or extreme energy and power constraints in common. The inventors have thus identified that system overhead needs to be addressed and optimized, in view of UEs operating under such severe power constraints, such as various types of UEs operating under 3GPP specifications. In the context of such UEs which are configured to operate under severe energy constraints, e.g., only capable of transmitting in response to receiving RF energy or other external energy stimulus, or which otherwise are configured to only transmit in response to a received trigger, operation of the UE may be entirely under the control of an application function or application server associated with the UE.

[0046] A study within 3GPP refers to low power or low complexity devices within the term Ambient loT. According to 3GPP TR 38.848 version 18.0.0 (2023-12), the study focuses on design targets for relevant use cases of a new 3GPP loT technology, on the basis of suitable deployment scenarios in a 3GPP system, which relies on ultra-low complexity devices with ultra-low power consumption for very-low end loT applications. Ambient loT devices are categorized in three different device types / sets in the study (though more or fewer are plausible) based on their energy storage capacity, and capability of generating RF signals for their transmissions:

[0047] Device A: No energy storage, no independent signal generation / amplification, i.e., backscattering transmission.

[0048] Device B: Has energy storage, no independent signal generation, i.e., backscattering transmission. Use of stored energy can include amplification for reflected signals.

[0049] Device C: Has energy storage, has independent signal generation, i.e., active RF components for transmission.

[0050] Target power consumption and device complexity for the three categories of ambient loT device are as follow:

[0051] For Device A, the power consumption target during transmitting / receiving is < 1 pW or < 10 pW, and the complexity target is to be comparable to RFID, For Device B, the target during transmitting / receiving is such that: o Device A power consumption « Device B power consumption < Device C power consumption; or o Device A power consumption < Device B power consumption < Device C power consumption.

[0052] Similarly, the target complexity is such that:

[0053] Device A complexity < Device B complexity < Device C complexity.

[0054] For device C, the device power consumption during transmitting / receiving is < 1 mW to < 10 mW and the complexity target orders-of-magnitude lower than Narrow Band - loT (NB-IoT).

[0055] A summary of the device categorization and their target power consumption is shown in table 1.

[0056] Table. 1 It may be noted that limited energy storage can be different among implementations within Device B or implementations within Device C, and different between Device B and Device C. Such storage is expected to be order(s) of magnitude smaller than an NB-IoT device would typically include. Devices of types A, B, and C are able to demodulate control, data, etc. from the relevant entity according to connectivity topology.

[0057] Going forward, the proposed solutions will be provided in the context of the UE 10 being configured as a low power device (LPD) 10, such as an Ambient loT (AIoT) device. An LPD may herein refer to a UE configured with an energy harvesting circuit, such as circuit 315 exemplified with reference to Fig. 3B. In one or more examples, an LPD is associated with a device type. In one or more examples, the device types may be categorized based on one or more capability sets, such as energy storage capability and / or synchronization capability, such as whether the circuitry of the LPD is active, semi-active or passive. The information provided in Table 1 provides one example of such device type categorization.

[0058] To support low-power connectivity, i.e., connectivity for LPDs such as AIoT devices, various network topologies are conceivable, as shown in Fig. 4. The examples shown in this drawing are provided in 3GPP TR 38.848. Network topology refers to the physical or logical layout of a network, defining how different nodes or devices are connected and how data is transmitted between them. In the context of the proposed solution, the LPD 10 may be configured to register and communicate with the wireless network 100 in different ways, where the LPD 10 may communicate directly with an access node 121, or where signals and / or data is conveyed via another device to the access node 121.

[0059] In this context, topology 1 relates to the LPD 10 communicates directly with an access nodel21 of the wireless network. Topology 2 refers to communication with the wireless network 100 via an intermediate node. Such transmissions between the LPD 10 and the access node 121 may e.g., be performed via the node 20, such as another UE, a relay, or a coverage enhancing device (CED). Topology 3 refers to communication with the wireless network 100 using an assisting node, such as a UE acting as the node 20. The shown alternatives refer to a) DL assistance and b) UL assistance. Topology 4 refers to communication with another communication node which need not involve related communication with the wireless network 100. In existing 3GPP loT standardization, the device first needs to fully scan all possible frequency ranges with certain channel raster, find the right base-station by measuring and decoding different sync signals and system info including Master Information Block (MIB) and System Information Block Type 1 (SIB1). The device performs the registration to the core network via random access procedure and then camp on the selected base station (access node). However, due to the target power consumption for LPDs, such as AIoT, being very limited compared to the existing low- power cellular connectivity (such as NB-IoT, Machine Type Communication (MTC)), existing registration and discovery, i.e. finding a suitable cell in Uu interface or discover / finding other UE as in sidelink, procedures would be very demanding. Nor do such legacy procedures support ambient loT type network topologies.

[0060] Various examples of the proposed solution are described below with reference to the signaling diagrams provided in Figs 5A and 5B. In these diagrams, the same reference numerals are used to identify the same or corresponding features and steps. Furthermore, some examples of the proposed solution may involve using resources dedicated for (or usable by) EPD devices, as further described with reference to Fig. 6. Additionally, flowcharts are provided in Figs 7, 8A, 8B and 9, covering various methods according to the proposed solution and as supported in the signaling diagrams of Figs 5 A and 5B.

[0061] The diagrams of Figs 5A and 5B show signaling between, and various actions taken in, the EPD labelled UE 10, the access node 121 of the wireless network 100, and one or more additional communication node 20, labelled assisting node (Ass. Node). In this context, the communication node 20 may be a UE 20 which is not an EPD, such as a mobile phone, a smart phone, a laptop, or other type of wireless communication device which has better features and functionalities than UE10. The proposed solution is based on the notion of the EPD 10 being able to register and connect to the wireless network 100 either by direct communication with the network through RAN 120 (represented by the access node 121) or either partly or completely by communication via another wireless device (represented by the communication node 20) which is wirelessly connectable to the wireless network 100. It may be noted that, in the context of the proposed solution, registering may refer to so-called initial registration, i.e., when the EPD 10 first registers to the wireless network. Alternatively, the proposed solution may apply to a stage of re-registration of the LPD 10, which by way of example may be triggered by mobility, such as when the LPD has left and re-entered a coverage area of the wireless network 100, by expiry of a timer in the LPD 100, or by channel conditions resulting in changed connectivity (e.g., termination of ability to monitor signaling from a certain communication node).

[0062] While it shall be noted that not all steps or actions provided in the signaling diagrams are included in the broadest scope of the proposed solution, each step of the signaling diagrams will be described in order, for the sake of easy understanding.

[0063] With reference to Figs 5A and 5B, the access node 121 may in some examples transmit 501 information 50 indicative of LPD registration support, identifying capability of registration by LPD broadcast signaling. Where this broadcast message is received and detected 502 by the LPD 10, this information thus provides that the LPD 10 is in an area where it can register (or connect, when registered) to the wireless network 100. The capability of the wireless network 100, or specifically the access node 121, of registering LPDs, can be indicated explicitly, e.g., in a message contained in the broadcast 50. In some examples the capability is indicated implicitly, e.g., by transmitting a specific reference / synch signal 50 dedicated for LPDs (e.g., AIoT devices). In some examples, the LPD 10 may be preconfigured to monitor one or more resources specifically dedicated for the broadcast 50. The broadcast 50 may in some examples be transmitted for a certain time period, such that radio frequency of the transmission 50 may be harvested for backscattering by devices configured e.g., according to Fig. 3B. In some examples, the broadcast 50 is indicative of resources or other configuration for LPDs to use for transmitting a registration request.

[0064] The LPD 10 may broadcast 503 a first UL message 51 indicative of a registration request, wherein the first UL message 51 comprises an ID of the LPD 10 in the wireless network 100. Broadcast, in this context, means that the message 51 can be received by any node, such as assistance node 20 and access node 121. The ID may be broadcasted 503 using some predetermined encryption methodology or code, which may be precoded in the LPD 10 or determined based on the received information 50. The ID may comprise, or be derived dependent on, hardcoded data in the LPD 10. In some examples, the ID can be a temporary ID or a full unique ID of the LPD 10. In some further examples, the ID is a subscription ID related to the wireless network 100. The ID may in some examples comprise SUPI (5G globally unique Subscription Permanent Identifier), or SUCI (encrypted SUPI). By broadcasting 503, any communication node in range, usable for assisting the LPD 10 in the registration process, is made aware of the registration request. In some examples, the first UL message is broadcasted within certain radio resources (e.g., resource pool) which is dedicated for a given device type, such as for an AIoT type device, or one of types A-C described above with reference to Table 1, or other definition of a low power or low complexity type wireless device. In some examples, the first UL message 51 is broadcast using a resource which is dedicated for LPD network registration, such as a specific resource or resources within the exemplified resource pool. Such resources are exemplified below with reference to Fig. 6. Broadcasting using such a dedicated resource may identify, to any communication node detecting the broadcast, that the transmission is specifically transmitted as a registration request. Rather than dedicating particular resources for registration requests, the first UL message may in some examples comprise an indicator which identifies a registration request, such as a flag, bit, or sequence. In some examples, the first UL message 51 may comprise capability signaling, which may be indicative of LPD type, such as one of types A, B or C. In other examples, this capability signaling is made separately, and not in the first UL message used for registration request. By way of example, with reference to Table 1, the broadcasting 503 may be carried out via ambient backscattering where the LPD 10 is a type A or B device, or with a simple modulation where the LPD 10 is a type C device.

[0065] The broadcasted first UL message 51 may be received 504 in the access node 121, and / or received 505 in one or more further communication nodes, such as node 20, which may assist the LPD 10 in connectivity and registration to the wireless network 100.

[0066] Going forward, Figs 5A and 5B illustrate alternative embodiments, which will be separately described. Herein, communication with regard to the wireless network 100 is indicated as carried out by access node 121. However, it shall be noted that registration of the LPD 10 with the wireless network 100 further comprises registration in the core network 110. The processes related to registration according to the proposed solution may thus further comprise communication between the access network 120 (e.g., access node 121) and the core network 110, or NAS (Non-Access Stratum) communication between the core network 110 and the LPD 10 and / or the further communication node 20. Communication with the core network 110 is not described in detail herein but is indicated by the core network 110 being shown in the background of the access node 121 in Figs 5A and 5B.

[0067] Fig. 5A describes network-based registration and topology discovery examples. Any communication node, such as assistance node 20, which receives 505 the broadcasted 51 registration message transmit 506 a report message 52 for receipt 507 in the access node 121. The report message 52 indicates / acknowledges reception of the registration request 51 in the communication node 20 and a measure or indication of the detected signal strength upon said reception. In this context, it shall be noted that the access node 121 need not have detected the registration request 51.

[0068] In step 508, the access node 121 determines or assigns one communication node to be in direct communication with the LPD 10 for operation of the registration process. According to some examples, this determination may comprise selecting the communication node having detected the highest signal strength. In some examples, where the access node 121 and the communication node 20 have detected equal signal strength in reception of the registration request 51, within some tolerance value, the access node 121 may be configured to select itself in step 508.

[0069] Where the access node 121 selects itself to be in direct communication with the LPD 10, it transmits 509 an acknowledgement (ACK) 55A of the registration request for reception 513 in the LPD 10, comprising or accompanied with by indication of the topology type supported or selected, such as one of topologies 1-3 in the example of Fig. 4. In this context, it may be noted that where acknowledgement is referred to herein, such acknowledgement may be conveyed in an acknowledgement message. The selected topology is further used after the registration to any UL and DL communication between UE 10 and the network (e.g., directly to Access node 121 or indirectly via Ass. Node 20).

[0070] Where the access node 121 selects communication node 20 to be in direct communication with the LPD 10, it transmits 510 a control message 53 for reception 511 in the control node 20, configuring the control node 20 to be in direct contact with the LPD 10, i.e., the closest communication node with regard to connectivity. The control message 53 may further indicate the topology type supported or selected, as described. The communication node 20 assigned by the access network in step 508 is configured by the control message 53 to transmit 512 an acknowledgement (ACK) 55B of the registration request to the LPD 10, comprising or accompanied by an indication of the topology type supported. After the registration, the UE 10 and the network communicate and perform UL and DL transmission via the selected topology.

[0071] In the examples of Fig. 5A, acknowledgements 55A and 55B are thus alternatives, and the LPD 10 will thus only receive one of them (if any).

[0072] Optionally, in any of these two scenarios, corresponding control messages may be transmitted to any further communication node which has transmitted a report message 52, where such control message indicates selected topology. Where such other communication node receives such a request message, which does not indicate its further involvement in the registration process, any record of the received registration request 31 may be erased.

[0073] Step 518 indicates that further steps for registration of the LPD 10 to the wireless network 100 are carried out. In this context, the LPD 10 is configured, by the request acknowledgement 55A or 55B to communicate with the wireless network 100 in accordance with the indicated topology.

[0074] Fig. 5B describes device-based examples of the proposed solution. Any communication node, such as access node 121 and assistance node 20 in the example shown in Fig. 5B, which receives 504, 505 the broadcasted 51 registration message, is configured to transmit 514, 515 an acknowledgement (ACK) 56 A, 56B of the registration request for reception 516 in the LPD 10, comprising a measure or indication of its signal strength. In this context, it shall be noted that the access node 121 or the communication node 20 need not have detected the registration request 51. The ACK messages 56A, 56B may further comprise an ID of the communication node 121, 20 that acknowledges reception, or otherwise be indicative of its node type, e.g., access node or assistance node, for the context of communication between the LPD 10 and the wireless network 100. In various examples, the ID of the node 20, 121 comprised in the acknowledgement may be encrypted or transmitted on an encryption link, as may be the case for the example described with reference to Fig. 5A.

[0075] In case the LPD 10 receives multiple ACKs 56 A, 56B, the LPD 10 continues the registration process with one of the nodes from which ACK was received 516. This is indicated in step 517 in Fig. 5B, where the LPD 10 determines or assigns one communication node to be in direct communication with the LPD 10 for operation of the registration process 518. According to some examples, this determination may comprise selecting the communication node having detected the highest signal strength. In some examples, where the access node 121 and the communication node 20 have detected equal signal strength in reception of the registration request 51, within some tolerance value, the LPD 10 may be configured to select the access node 121 in step 507. Any communication node 121, 20 that is not selected in step 517 may be configured to erase any record of the received registration request 51 if the LPD 10 device does not communicate with them within a certain time period.

[0076] Fig. 6 illustrates an example resource allocation 66, such as a resource pattern, available to be used for UL transmission of information or data from LPDs, such as LPD 10. The example resource allocation may be a predetermined resource allocation, such as a generic resource allocation, available to be used for UL transmission from the LPDs. In another example, a similar predetermined resource allocation can be defined for DL transmission from the access node 121 (not shown in Fig.6). In another example, a similar predetermined resource allocation can be defined for both UL / DL transmission with regard to the access node 121 (not shown in Fig.6). For communication between the LPD 10 and the communication node 20, a Sidelink configuration of resources may instead be used. The generic resource allocation may comprise a plurality of time windows 62, such as Uplink Transmission Windows (UTWs), in which an UL transmission from the LPD can be performed. In the example resource allocation of Fig. 6, a first time window 62A, a second time window 62B, and a third time window 62C is shown. The time windows 62, 62A, 62B, 62C, may be separated by a DTX (discontinuous transmission) period 64. In one or more examples, DTX cycles can be defined based on an expected periodicity of an UL transmission, such as based on a DTX period 64, and / or a latency requirement of the LPD. In other words, a plurality of LPDs may be scheduled in the same time window. Furthermore, a plurality of LPDs may also be scheduled with different DTX periodicity.

[0077] Each time window 62 may comprise a plurality of transmission opportunities (TOs) 66. Each TO may comprise one or more time and / or frequency resources. A TO can herein be seen as a subset of the resources, such as time and frequency resources, comprised within the time window. Each TO may be associated with one or more LPD, such as a group of LPDs. In other words, different LPDs or groups of LPDs can be allocated in different TOs, such as in different time and / or frequency resources within a time window. The time windows 62 may be associated with a discontinuous transmission (DTX) pattern and a resource size, with the DTX pattern being associated with a DTX period 64. Each transmission cycle of the LPD may be a time window for UL transmission, such as an UL transmission window) comprising one or more transmission opportunities (TOs), with certain time and frequency distance between two consecutive transmission opportunities in one time window. In one or more examples, the UL transmission window may be a resource allocation available to multiple LPDs and / or a group of LPDs. In one or more examples, the UL transmission windows may be seen as a configuration that is applicable to multiple LPDs and / or to a group of LPDs. In one or more examples, resource configuration can be indicative of one or more TOs 66, such as resources associated with a time opportunity. The allocation of transmission opportunities within each time window for each LPD, may be dependent on a capability, such as a synchronization capability, of the LPD. Allocation of transmission opportunities may in such examples be determined based on LPD type, e.g., type A, B or C, which may be identified be capability signaling. As mentioned, this may in some examples be conveyed in the first UL message 51. In one or more examples, the configuration of transmission opportunities allocation is predefined or it can be conveyed by the network node to the LPDs. In one or more examples, an LPD having coarse -synchronization capability may not be scheduled in the first few TOs in each time window, while an LPD having high- synchronization capability, such as a fine synchronization capability, may be scheduled in the first few TOs in each time window.

[0078] The wireless network 100 may broadcast information, e.g., by the access node 121, indicative of one or more predetermined resource configurations for UL transmission by LPDs, e.g., LPD 10, such as a generic resource configuration for UL transmission by the LPDs. The one or more predetermined resource configurations may be indicative of the resource allocation available to be used for UL transmissions of data from LPDs, such as the example resource allocation shown in Pig. 6. The resource allocation available to be used for UL transmissions of data from LPDs can be seen as an entirety of the resources that are available for data transmission from any LPD. The predetermined resource configurations can also be used by the Assistance Node 20 in case the assistance Node 20 communicates with the LPD 10. In one or more example methods, the one or more predetermined resource configurations may be indicative of a plurality of different resource subsets within the resource allocation of the predetermined resource configurations, such as of the entirety of the resource allocation. The plurality of different resource subsets may thus be parts of the entirety of the resources that are available for LPDs for UL transmission. The plurality of different resource subsets may for example be dedicated to different types of LPDs, or different groups of LPDs, and / or may be dedicated to different types of transmissions.

[0079] By way of example, and with reference to the proposed solution, resources of the resource allocation 66 may be used upon registration of the LPD 10 to the wireless network 100. In some examples, the LPD 10 may transmit anywhere and at any time within the given resource pool of the resource allocation 66. In other examples, the LPD 10 may transmit within certain time and frequency resources dedicated for registration purposes. One or more specific resources of the resource allocation 66 may thus define a resource subset dedicated for registration transmissions, allowing the LPD 10 to register to the wireless network 100. The resource subset dedicated for registration may be used for broadcasting 503 the registration request 51. In some examples, different resource subsets may be allocated for registration for different types of LPDs, such as types A, B, and C discussed above.

[0080] Fig. 7 provides a flowchart of a method carried out in the LPD 10 according to various examples of the proposed solution. The LPD 10, comprising the wireless transceiver 313 and the logic circuitry 310 is furthermore configured to carry out the steps of Fig. 7. Reference will further be made to the examples of Figs 5A and 5B, where applicable, to indicate corresponding steps.

[0081] According to one aspect of the proposed solution, a method is provided for use in an LPD 10 upon registering to a wireless network. In broad terms, the method may comprise the following steps:

[0082] 700: Monitoring information signaling from the wireless network. This may involve listening in predetermined resources for DL broadcasting. Specifically, this may involve monitoring reception 502 of information 50 indicative of network support for registration by broadcast signaling. In some examples, this may further comprise harvesting RF energy obtained upon receiving said information, transmitted from an access node of the wireless network.

[0083] 705: Broadcasting a first UL message indicative of a registration request 51, comprising an ID of the LPD 10 in the wireless network. The message can be encrypted for the security reasons. The first UL message may be transmitted in resources that can be defined to be used by LPDs (e.g., dedicated resources or non-dedicated resources), or a type of LPDs, optionally in specific resources dedicated for registration request transmission within a pool of resources dedicated for LPDs. The resources may be defined to be used by LPDs by being predetermined in a specifiation, or by decision and configuration in the RAN 120, such as access node 121, and informed by broadcasting system information or by other network signaling. Broadcasting of the first UL message may be accomplished by using the energy harvested in conjunction with receiving the DL broadcasting 50.

[0084] 710: Receiving, from at least one communication node, an acknowledgement 55A / 55B, 56A, 56B, comprising a node ID of a communication node which received the first UL message. In some examples, which are network-based, only one acknowledgement may be received, either 55A or 55B. In other examples, related to a device-based solution, several acknowledgements may be received from different communication nodes.

[0085] 715: Determining initial network topology based on the acknowledgement. In a network-based solution, the initial network topology may be determined by receiving an indication of the initial network topology in the acknowledgement 55A or 55B. In a UE- based alternative, determining initial network topology may further comprise selection 517 of a communication node, based on the received acknowledgement. In some examples, of any of the alternatives, the indication of the initial network topology may comprise the ID of the selected communication node which transmitted the acknowledgement, wherein determining initial network topology may comprise mapping the ID or ID type of the selected communication node to a communication node type, which indicates the initial network topology. In other examples, the particular radio resources used by the selected communication node for DL transmission of the acknowledgement may be an indication based on which the identify the initial network topology can be determined in the LPD 10.

[0086] In some examples, determining initial network topology may comprise determining or mapping to a resource configuration, indicative of radio resources in time and / or frequency, for use in communication with the wireless network, i.e., for UL and / or DL communication with a node 20, 121 which is communicatively closest to the LPD 10 according to the initial network topology.

[0087] 720: Registering with the wireless network based on the determined initial network topology. This may correspond to step 518 of Figs 5A and 5B. Registering based on the determined initial network topology may involve using a resource configuration for UL and / or DL communication determined based on the determined initial network topology. Registration based on the determined initial network topology may, in some examples, include using a Sidelink configuration where the communicatively closest node 20 is a UE acting as assisting node or include using a simplified or a new protocol suitable for ambient loT. Registration based on the determined initial network topology may, in some examples, include selecting modulation or encoding, based on the communicatively closest node according to the determined initial network topology. The actual registration is as such not part of the proposed solution. Specifically, this part may be carried out using legacy features and steps and is therefore not described in detail.

[0088] Figs 8A and 8B provide flowcharts of methods carried out in the access node 121 of the wireless network 100 according to various examples of the proposed solution. Fig. 8A shows a network-based alternative, whereas Fig. 8B shows a device-based alternative. Both correspond to the different alternative as described above. The access node 121, comprising the wireless transceiver 213 and the logic circuitry 210, is furthermore configured to carry out the steps of Figs 8A and 8B in various examples. Both alternatives comprise the following steps:

[0089] 800: Transmitting information 50 indicative of network support or capability of registration by broadcast signaling from EPDs. This corresponds to step 501. The capability or support of the wireless network 100, or specifically the access node 121, of registering EPDs, can be indicated explicitly, e.g., based information included in a message contained in the broadcast 50, such as one or more bits indicating the support of EPD and / or EPD’s type. In some examples the capability is indicated implicitly, e.g., by transmitting a specific reference / synch signal 50 dedicated for EPDs (e.g., AIoT devices). Once the EPD is able to detect the reference / synch signal, the EPD assumes the network support the operation of LPDs in that network. The broadcast 50 may in some examples be transmitted for a certain time period, such that radio frequency of the transmission 50 may be harvested for backscattering by devices configured e.g., according to Fig. 3B. The broadcast may be carried out using radio resources which, in frequency, overlap a resource pool 66 configured for LPDs to respond to request registration. The transmission of the information 50 may comprise, or be transmitted in conjunction with, a signal providing RF energy for harvesting by LPDs operating a backscattering type transmission, as explained with reference to Fig. 3B. 805: Receiving a first UL message indicative of a registration request 51, comprising an ID of the LPD 10 in the wireless network. The first UL message may be received in resources dedicated for use by LPDs, or a type of LPDs, optionally in specific resources dedicated for registration request transmission within a pool of resources dedicated for LPDs.

[0090] 810: Controlling transmission of an acknowledgement 55A, 55B, 56A of the first UL message, said acknowledgement comprising a node ID.

[0091] Different examples apply for network-based embodiments and for device-based embodiments.

[0092] With reference to a network-based alternative of Fig. 8A, the step 810 of controlling transmission of an acknowledgement may further comprise any of the following steps811-814:

[0093] 811: Receiving, from at least one communication node 20, a report message 52 as described with reference to Fig. 5A, acknowledging receipt of the first UL message and an indication of signal strength upon receiving the first UL signal.

[0094] 812: Selecting initial network topology. This may involve selecting, among itself 121 and any communication device 20 from which a report message 52 is received, one communication node for nearest communication with the LPD 10 for registration to the wireless network 100. This may be determined based on signal strength, as described.

[0095] 813: Where another communication node 20 is selected, a control message 53 may be transmitted to that communication device 20, thereby configuring that communication device to transmit an acknowledgement 55B to the LPD 10.

[0096] 814: Where, on the other hand, it is selected in step 812 to proceed with the access node 121 for nearest communication with the LPD 10 for registration, the access node transmits an acknowledgement 55A to the LPD 10.

[0097] In any of steps 813 and 814, an indication of the selected initial network topology is included in the acknowledgement.

[0098] Where step 813 is included, the method may further comprise:

[0099] 815: Erasing any record of the registration request from the LPD 10.

[0100] Where instead step 814 is included, the method may further comprise:

[0101] 820: Proceeding to register the LPD 10 to the wireless network.

[0102] Fig. 9 provides a flowchart of methods carried out in the communication node 20, which may be a UE 20 acting as an assisting node in the registration of the LPD 10. Fig. 9 shows a network-based alternative, corresponding to the examples laid out in the foregoing. The communication node 20 may be configured in accordance with an example of the UE described with reference to Fig. 3A, as explained, though not as an LPD but rather as a legacy UE, such as a mobile phone, a computer, or other wireless device. The communication node 20 may thus comprise the wireless transceiver 313 and the logic circuitry 310 and be configured to carry out the steps of Fig. 9 in various examples. The method may comprise:

[0103] 905: Receiving a first UL message indicative of a registration request 51, comprising an ID of the LPD 10 in the wireless network. The first UL message may be received in resources dedicated for use by LPDs, or a type of LPDs, optionally in specific resources dedicated for registration request transmission within a pool of resources dedicated for LPDs.

[0104] 910: Controlling transmission of an acknowledgement of the first UL message, said acknowledgement comprising a node ID.

[0105] The step 910 of controlling transmission of an acknowledgement may further comprise any of the following steps 911-913:

[0106] 911: Transmitting, to an access node 121, a report message 52 as described with reference to Fig. 5A, reporting receipt of the first UL message in the communication node and an indication of signal strength upon receiving the first UL signal.

[0107] As described herein, further handling of the registration preparation and execution is dependent on topology selection in the access node 121.

[0108] Where the communication node is selected in the topology selection 508, the method further comprises:

[0109] 912: Receiving a control message 53 from the access node 121, thereby being configured to transmit an acknowledgement 55B to the LPD 10.

[0110] 913: Transmitting the acknowledgement 55B to the LPD 10.

[0111] 920: Step 913 may be proceeded with the communication node 121 as the nearest communication node, operating as assisting node, in the registration of the LPD to the wireless network 100.

[0112] 915: If another topology selection is made by the access node 121, the communication node 20 may be arranged to erase any record of the registration request from the LPD 10, e.g., triggered by a timer running out after transmitting the report message in step 911. Various examples have been described above related to initial network topology. According to some aspects, the initial network topology may comprise an indication of any of ID, type, or role, of the communication node 20, 121 which is communicatively closest to the LPD 10. In some examples, the initial network topology may comprise, or be indicative of, resource configuration, scheduling, coding, modulation, or other communication parameters to use for further communication involved in the registration 518 or after registration. In this context, the determination of the initial network topology in the LPD 10, if obtained based on indication from the access node 121 or other communication node 20 in a network-based alternative, or determined based on received acknowledgements in a device-based alternative, is advantageous for the further operation of the LPD 10 in the registration process.

[0113] Table 2 below provides examples of determination 715 of initial network topology based on the acknowledgement, according to some embodiments. Here, the communication node 20 which may operate as an assistance device is labelled UE 20. The first column defines three alternatives related to reception in the LPD 10 of acknowledgement(s). The uppermost label of columns 2 and 3 identify what node ID is received in the acknowledgement. Note that * indicates that the node ID of the communication node that received the registration request is diverted via the assistance node 20 or access node 121 to the LPD 10.

[0114] Table 2. Various aspects of the proposed solution have been described in the foregoing.

[0115] Unless where clearly contradictory, the features of any example provided herein may be combined in any way within the scope defined by the appended claims.

Claims

CLAIMS1. A method carried out in a low power device, LPD, upon registering to a wireless network, the method comprising: broadcasting (705) a first uplink, UL, message indicative of a registration request, comprising an ID of the LPD in the wireless network; receiving (710), from at least one communication node, an acknowledgement comprising a node ID of a communication node which received the first UL message; determining (715) initial network topology based on the acknowledgement.

2. The method of claim 1, wherein the first UL message is broadcasted within a resource pool which is defined to be used by a given device type.

3. The method of claim 2, wherein the acknowledgement is received in a resource associated with said resource pool.

4. The method of any preceding claim, wherein the first UL message is encrypted using a predetermined encryption methodology or code.

5. The method of any preceding claim, wherein the first UL message is indicative of LPD-type.

6. The method of any preceding claim, wherein the first UL message is broadcasted using a resource which is dedicated for network registration.

7. The method of any of claims 1-5, wherein the first UL message further comprises an indicator which identifies a registration request.

8. The method of any preceding claim, comprising: monitoring (700) information signaling from the wireless network; wherein the broadcasting is made upon receiving, based on the monitoring, information indicative of network support for registration by broadcast signaling.

9. The method of any preceding claim, comprising: harvesting radio frequency, RF, energy obtained upon receiving an RF signal from the wireless network; wherein the broadcasting is made using the harvested energy.

10. The method of claim 8 and 9, wherein said information is received on said RF signal.

11. The method of any preceding claim, wherein the node ID is indicative of initial network topology of connectivity for the LPD device.

12. The method of any of claims 1-10, wherein the initial network topology is determined by the wireless network and indicated in the acknowledgement (55A, 55B).

13. The method of any of claims 1-11, wherein the receiving comprises receiving acknowledgements (56A, 56B) from a plurality of communication nodes, and wherein the determining comprises selecting (517) initial network topology based on the reception of said acknowledgements.

14. The method of any preceding claim, wherein the node ID is indicative of said first communication node being an access node of the wireless network or a user equipment, UE, which is wirelessly connected to the wireless network.

15. A low power device, LPD, comprising: a wireless transceiver; and logic circuitry configured to control the LPD to carry out the steps of any of claims 1-14.

16. The LPD of claim 15, wherein said wireless transceiver is configured to operate on a low-complexity modulation.

17. The LPD of claim 16, wherein said modulation is one of On-Off Keying, OOK, modulation, binary frequency shift keying, BFSK, and binary phase shift keying, BPSK.

18. The LPD of claim 16 or 17, wherein said transceiver is configured to operate using backscattering communication.

19. The LPD of any of claims 15-18, further comprising: a harvesting module, configured to harvest radio frequency energy obtained from a received signal, wherein the wireless transceiver and the logic circuitry are powered by the harvesting module.

20. A method carried out in a communication node upon registration of a low power device, LPD, to a wireless network, the method comprising: receiving (805, 905) a first uplink, UL, broadcast message comprising an ID of the LPD in the wireless network; controlling (810, 910) transmission of an acknowledgement of the first UL message, said acknowledgement comprising a node ID.

21. The method of claim 20, wherein the communication node is an access node of the wireless network, wherein controlling transmission of an acknowledgement comprises: receiving (811), from at least one further communication node, a report message acknowledging receipt of the first UL message and an indication of signal strength upon receiving the first UL signal; selecting (812) initial network topology for registering the LPD 10 based on the report message.

22. The method of claim 21, wherein selecting (812) initial network topology comprises: transmitting (814) the acknowledgement to the LPD; ortransmitting (813), to a selected communication node among said at least one further communication node, a control message to configure said selected communication node to transmit the acknowledgement to the LPD.

23. The method of any of claims 20-22, further comprising: broadcasting information indicative of network support for registration by UL broadcast signaling.

24. The method of claim 19, wherein the communication node is an assisting communication node connected to an access node of the wireless network, wherein controlling transmission of an acknowledgement comprises: transmitting (911), to the access node, a report message acknowledging receipt of the first UL message and an indication of signal strength upon receiving the first UL signal.

25. The method of claim 24, further comprising: transmitting (913), upon receiving (912) a control message from the access node the acknowledgement to the LPD.

26. The method of any of claims 20-25, wherein the first UL message is received within a resource pool which is defined for use by a given device type.

27. The method of claim 25 wherein the acknowledgement is transmitted in a resource associated with said resource pool.

28. The method of claims 20-27, wherein the first UL message is received in a resource which is dedicated for network registration.

29. The method of any of claims 20-27, wherein the first UL message further comprises an indicator which identifies a registration request.

30. A communication node, comprising: a wireless transceiver; andlogic circuitry configured to control the communication node to carry out the steps of any of claims 20-29.

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