Preamble design for a-iot

Abstract

Methods, systems and apparatuses for Device-to-Reader (D2R) or Reader-to- Device (R2D) communication are disclosed In an example embodiment, a method implemented in a device is provided. The method comprises transmitting a first signal, the first signal including a first timing acquisition signal; and receiving, in response to the first signal, a second signal, the second signal including a second timing acquisition signal.

Description

PREAMBLE DESIGN FOR A-IOTTECHNICAL FIELD

[0001] The present disclosure relates to wireless communications, and in particular, to design of Reader-to-Device (R2D) or Device-to-Reader (D2R) communication.BACKGROUND

[0002] The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile User Equipments (UEs), as well as communication between network nodes and between UEs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0003] 3 GPP Release 18 (Rel-18) Ambient Internet of Things (loT) Study Item (SI) concluded with 3 GPP Technical Report (TR) 38.848. In a follow-up Release 19 (Rel-19) Ambient loT SI (RP-240826), three device types are being studied.Related agreements

[0004] For the purpose of the study, RANI uses the following terminologies:• Device 1: ~1 pW peak power consumption, has energy storage, initial sampling frequency offset (SFO) up to Itf ppm, neither downlink (DL) nor uplink (UL) amplification in the device. The device ’s UL transmission is backscattered on a carrier wave provided externally.• Device 2a: < a few hundred pW peak power consumption, has energy storage, initial SFO up to 10 ' ppm, both DL and / or UL amplification in the device. The device ’s UL transmission is backscattered on a carrier wave provided externally.• Device 2b: < a few hundred pW peak power consumption, has energy storage, initial SFO up to 10 ' ppm, both DL and / or UL amplification in the device. The device ’s UL transmission is generated internally by the device.

[0005] The general scope of 3 GPP Technical Specification Group Radio Access Network (TSG RAN), RAN Work Group 1 (WG1) (RANI) led objectives are as follows:Study necessary and feasible solutions for Ambient loT as prescribed in the General Scope, including decisions on which functions, procedures, etc. are needed and not needed, and ensuring at least the required functionalities in, e.g., Section 6.2 of 3GPP PR 38.848.Study of positioning in Rel-19 is TSG RAN WG 3 (RAN3)-led, limited to functionalities which would have no, or minimal, specification impact (note: this does not imply any decision relating to work item (WI) creation).Study the feasibility and required functionalities for proximity determination (coordination with 3GPP TSG SA WG3 (SA3) is required for privacy aspects).• RANI -led:For the Ambient loT DL and UL: o Frame structure, synchronization and timing, multiple access o Numerologies, bandwidths, and multiple access o Waveforms and modulations o Channel coding o Downlink channel / signal aspects o Uplink channel / signal aspects o Scheduling and timing relationships o Study necessary characteristics of carrier-wave waveform for a carrier wave provided externally to the Ambient loT device, including for interference handling at Ambient loT UL receiver, and at NR network node.For Topology 2, no difference in physical layer design from Topology 1.

[0006] Recent RANI progress on the frame structure aspects in RAN1 116 has the agreements copied below:signal, control fields, guard periodDelimiter

[0007] Delimiter is used in radio frequency identification (RFID) to indicate the end of energy harvesting and the start of timing calibration signal. Whether it can be reused for Ambient loT was discussed, e.g., in RAN1 116 with the following proposal in Rl-2401857, which was not agreed upon.

[0008] Proposal 2.1.1-3 (with strikethrough and bolding of text):For ambient loT devices, if preamble-based downlink synchronization is supported considered, then one of the following options is considered for signaling the start of the delimiter for downlink transmission• Alt. 1: Delimiter is not needed, and preamble can serve the purpose of delimiter, i.e. is considered to signal the start of downlink reception• Alt. 2: Delimiter is considered and embedded within the preamble to signal the start of downlink reception • Alt. 3: Delimiter is considered to signal the start of downlink reception and added separately before the preamble

[0009] Proposals from companies are reproduced below:

[0010] FIG. 1 illustrates pre-ambles / sync-frame design for Ambient loT DL and was included in these proposals.

[0011] Recent RANI progress on the frame structure aspects in RAN1 116 has the agreements copied below:

[0012] R2D timing acquisition signal (e.g. R2D preamble) precedes R2D transmission in time domain, which serves as timing acquisition and indicates the start of the R2D transmission. However, several problems are to be sorted out, including:- how devices are able to identify the start of the D2R timing acquisition signal - whether / how timing acquisition signal can indicate the start of the R2D transmission, if devices miss the first part of the signal due to low energy

[0013] A counterpart of D2R timing acquisition signal was also agreed. Passive devices backscatter signal from carrier wave (CW) node for D2R transmission. In addition to the two problems above, another problem for passive devices’ D2R transmission is how to distinguish between D2R timing acquisition signal and carrier wave, both received from CW nodes. Devices modulate their data with CW, however they may not do so for D2R timing acquisition signal.

[0014] The following proposal was discussed and not agreed upon. It tries to use delimiter to indicate the start of an upcoming R2D data.SUMMARY

[0015] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Some embodiments herein advantageously provide methods, systems, and apparatuses for design of R2D or D2R communication.

[0016] One aspect of the invention provides a method performed by a device for communication with a reader. The method comprises receiving a first signal. The first signal includes a first timing acquisition signal. The method further comprises transmitting, in response to the first signal, a second signal. The second signal includes a second timing acquisition signal.

[0017] Another aspect of the invention provides a method performed by a reader for communication with a device. The method comprises transmitting a first signal. The first signal includes a first timing acquisition signal. The method further comprises receiving, in response to the first signal, a second signal. The second signal includes a second timing acquisition signal.

[0018] Another aspect of the invention provides a device for communication with a reader. The device is configured to and / or comprises a radio interface and / or processing circuitry configured to receive a first signal and transmit, in response to the first signal, a second signal. The first signal includes a first timing acquisition signal. The second signal includes a second timing acquisition signal.

[0019] Another aspect of the invention provides a reader for communication with a device. The reader is configured to and / or comprises a radio interface and / or processing circuitry configured to transmit a first signal and receive, in response to the first signal, a second signal. The first signal includes a first timing acquisition signal. The second signal includes a second timing acquisition signal.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0021] FIG. 1 is a block diagram of pre-ambles / sync-frame design for Ambient loT DL;

[0022] FIG. 2 is a schematic diagram of an example network architecture illustrating a communication system according to principles disclosed herein;

[0023] FIG. 3 is a block diagram of a network node in communication with a user equipment over a wireless connection according to some embodiments of the present disclosure;

[0024] FIG. 4 is a flowchart of an example process in a reader (e.g., network node) according to some embodiments of the present disclosure;

[0025] FIG. 5 is a flowchart of an example process in a device (e.g., user equipment) according to some embodiments of the present disclosure;

[0026] FIG. 6a-b are block diagrams of signals containing preamble and midamble according to some embodiments of the present disclosure; and

[0027] FIG. 7 is a schematic diagram of effects of distance on the timing acquisition signal according to some embodiments of the present disclosure.DETAILED DESCRIPTION

[0028] Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to design of R2D or D2R communication. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0029] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will befurther understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0030] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0031] In some embodiments described herein, the term “coupled”, “connected”, and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0033] The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multistandard radio (MSR) radio node such as MSR BS, multi-cell / multicast coordination entity (MCE), relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” usedherein may be used to also denote a user equipment (UE) such as a wireless device (WD) or a radio network node.

[0034] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of user equipment capable of communicating with a network node or another UE over radio signals, such as a wireless device (WD). The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low-cost and / or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device etc.

[0035] The terminologies gNB, UE, intermediate node, network node, and directly connected node may be used interchangeably, reflecting the network entity with which an A-IoT device is connected to.

[0036] Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi -cell / multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[0037] Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0038] Note further, that functions described herein as being performed by a user equipment or a network node may be distributed over a plurality of user equipments and / or network nodes. In other words, it is contemplated that the functions of the network node and user equipment described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the artto which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0040] Some embodiments are directed to design of R2D or D2R communication, e.g., design and / or detection of preambles in R2D or D2R communication.

[0041] Referring to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 2 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first user equipment (UE) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second UE 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of UEs 22a, 22b (collectively referred to as user equipments 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding network node 16. Note that although only two UEs 22 and three network nodes 16 are shown for convenience, the communication system may include many more UEs 22 and network nodes 16.

[0042] Also, it is contemplated that a UE 22 can be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a UE 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, UE 22 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0043] A network node 16 (eNB or gNB) is configured to include a NN delimiter unit 24 which is configured to perform one or more network node 16 functions, including functions related to R2D or D2R communication, e.g., detection of preamble and midamble in R2D or D2R communication. A user equipment 22 is configured to include aUE delimiter unit 26 which is configured to perform one or more UE 22 functions, including functions related to R2D or D2R communication, e.g., detection of preamble and midamble in R2D or D2R communication.

[0044] Example implementations, in accordance with an embodiment, of the UE 22 and network node 16 discussed in the preceding paragraphs will now be described with reference to FIG. 2.

[0045] The communication system 10 includes a network node 16 provided in a communication system 10 and including hardware 28 enabling it to communicate with the UE 22. The hardware 28 may include a radio interface 30 for setting up and maintaining at least a wireless connection 32 with a UE 22 located in a coverage area 18 served by the network node 16. The radio interface 30 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 30 includes an array of antennas 34 to radiate and receive signal(s) carrying electromagnetic waves.

[0046] In the embodiment shown, the hardware 28 of the network node 16 further includes processing circuitry 36. The processing circuitry 36 may include a processor 38 and a memory 40. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 36 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 38 may be configured to access (e.g., write to and / or read from) the memory 40, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0047] Thus, the network node 16 further has software 42 stored internally in, for example, memory 40, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 42 may be executable by the processing circuitry 36. The processing circuitry 36 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by network node 16. Processor 38 corresponds to one or more processors 38 for performing network node 16 functions described herein. The memory 40 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, thesoftware 42 may include instructions that, when executed by the processor 38 and / or processing circuitry 36, causes the processor 38 and / or processing circuitry 36 to perform the processes described herein with respect to network node 16. For example, processing circuitry 36 of the network node 16 may include NN delimiter unit 24 which is configured to perform one or more network node 16 functions, including functions related to R2D or D2R communication, e.g., detection of preamble and midamble in R2D or D2R communication.

[0048] The communication system 10 further includes the UE 22 already referred to. The UE 22 may have hardware 44 that may include a radio interface 46 configured to set up and maintain a wireless connection 32 with a network node 16 serving a coverage area 18 in which the UE 22 is currently located. The radio interface 46 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 46 includes an array of antennas 48 to radiate and receive signal(s) carrying electromagnetic waves.

[0049] The hardware 44 of the UE 22 further includes processing circuitry 50. The processing circuitry 50 may include a processor 52 and memory 54. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 50 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 52 may be configured to access (e.g., write to and / or read from) memory 54, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0050] Thus, the UE 22 may further comprise software 56, which is stored in, for example, memory 54 at the UE 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the UE 22. The software 56 may be executable by the processing circuitry 50. The software 56 may include a client application 58. The client application 58 may be operable to provide a service to a human or non-human user via the UE 22.

[0051] The processing circuitry 50 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by UE 22. The processor 52 corresponds to one or more processors 52 forperforming UE 22 functions described herein. The UE 22 includes memory 54 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 56 and / or the client application 58 may include instructions that, when executed by the processor 52 and / or processing circuitry 50, causes the processor 52 and / or processing circuitry 50 to perform the processes described herein with respect to UE 22. For example, the processing circuitry 50 of the user equipment 22 may include UE delimiter unit 26 which is configured to perform one or more UE 22 functions, including functions related to R2D or D2R communication, e.g., detection of preamble and midamble in R2D or D2R communication.

[0052] In some embodiments, the inner workings of the network node 16 and UE 22 may be as shown in FIG. 3 and independently, the surrounding network topology may be that of FIG. 2.

[0053] The wireless connection 32 between the UE 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve.

[0054] Although FIGS. 2 and 3 show various “units” such as NN delimiter unit 24 and UE delimiter unit 26 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

[0055] FIG. 4 is a flowchart of an example process 400 in a network node 16 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of the reader (e.g., network node 16) such as by one or more of processing circuitry 36 (including the NN delimiter unit 24), processor 38, and / or radio interface 30. The device is configured to transmit a first signal, the first signal including a first timing acquisition signal (Block SI 00). The device is configured to communicate with the reader (e.g., UE 22) based on the first transmitted signal (Block SI 02).

[0056] In some embodiments, the reader (e.g., network node 16) is further configured to receive a second signal, the second signal including a second timing acquisition signal.

[0057] In some embodiments, a time between the first signal and the second signal is based on at least one of a timing capability of the device and an energy storage of the device.

[0058] In some embodiments, a duration of the timing acquisition signal is based on at least one of a processing time of the device and a distance between the reader and the device.

[0059] FIG. 5 is a flowchart of an example process 500 in a device (e.g., user equipment 22) according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of the device such as by one or more of processing circuitry 50 (including the UE delimiter unit 26), processor 52, and / or radio interface 46. The device is configured to receive a first signal, the first signal including a first timing acquisition signal (Block SI 04). The device is configured to communicate with the reader (e.g., network node 16) based on the first received signal (Block SI 06).

[0060] In some embodiments, the device is further configured to transmit a second signal, the second signal including a second timing acquisition signal.

[0061] In some embodiments, a time between the first signal and the second signal is based on at least one of a timing capability of the device and an energy storage of the device.

[0062] In some embodiments, a duration of the timing acquisition signal is based on at least one of a processing time of the device and a distance between the reader and the device.

[0063] Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for R2D or D2R communication, e.g., detection of preamble and midamble in R2D or D2R communication. One or more device (e.g., UE 22) functions described below may be performed by one or more of processing circuitry 50, processor 52, UE delimiter unit 26, etc. One or more reader (e.g., network node 16) functions described below may be performed by one or more of processing circuitry 36, processor 38, NN delimiter unit 24, etc.

[0064] Some embodiments described herein may considered or assume use case with ultra-low power devices, low power device, zero-energy or ambient loT devices. However, the solutions should not be limited to such devices, and can be extended other service / device classes or categories, e.g., related to enhanced mobile broadband (eMBB), extended reality (XR), wearables, industrial loT, massive- machine type communication (MTC), ultra-reliable low latency communications (URLLC), and / or time sensitive networking (TSN).

[0065] Note that though preamble is mentioned as an example of timing acquisition signal, as used herein, preamble and midamble may refer to sequences put at different positions in a Physical Reader-to-Device Channel (PRDCH) or Physical Device-to- Reader Channel (PDRCH), other than timing acquisition signal.

[0066] Timing acquisition signal in a PRDCH may have variable duration, which a reader would adjust based on the device types in its coverage. It gives the flexibility to the network to have a variable length of timing acquisition signal, i.e., when the device (e.g., UE 22) is experiencing high UL timing errors, the network node 16 may send a long signal and when the device is having low timing errors, the network node 16 may provide a short signal. It is possible because a reader is able to know devices’ type, for example, from inventory query.

[0067] Therefore, in some embodiments, duration of R2D timing acquisition signal is based on devices’ type, namely their timing capability. Longer R2D timing acquisition signal is configured / predetermined for devices with lower timing capability.

[0068] In some embodiments, sequences immediately before and / or after timing acquisition signal can be designed in one or more of the following ways. These sequences can be generated by, e.g., readers (e.g., network node 16), CW nodes (e.g., network node 16), or devices (e.g., UEs 22).

[0069] A sequence called preamble ahead of a timing acquisition signal can indicate the subsequent timing acquisition signal and its duration. A sequence called midamble may immediately follow timing acquisition signal and indicates the end of timing acquisition signal and the start of the following data transmission.

[0070] FIG. 6a-b depicts preamble and midamble. For R2D midamble, when a device successfully decodes a preamble, it knows when the R2D timing acquisition signal would end and when it should receive the subsequent control or data. However, a device (e.g., UE 22) may be unavailable for some time due to low energy. When it is charged and wakes up, it may have missed the preamble and only receives part of the R2D timingacquisition signal. Nevertheless, it may be able to get synchronized but unaware when the timing acquisition signal would end. This motivates the need of a midamble in PRDCH.

[0071] Therefore, in some embodiments, both preamble and midamble may be needed and used in PRDCH.

[0072] In some embodiments, in addition to D2R timing acquisition signal and carrier wave, CW nodes (e.g., network node 16) generate D2R preamble and D2R preamble before and after D2R timing acquisition signal for passive devices’ (e.g., UE 22) backscattering. The reason is that the purpose of D2R preamble is to indicate the start of D2R timing acquisition signal, and that of D2R midamble is to indicate the start of CW wave which passive devices modulate with their data.

[0073] In some embodiments, D2R preamble and D2R midamble may not be needed for active devices.

[0074] In some embodiments, midamble can be a square wave coded with a sequence.

[0075] In some embodiments, preamble and midamble from reader to device are signals generated based on a sequence mapped in frequency domain.

[0076] In some embodiments, preamble and midamble from device to reader are signals generated based on a sequence mapped in time domain.

[0077] Note that it was agreed that TR2D is the minimum Time between an R2D transmission and the corresponding D2R transmission following it. It is actually the device processing time.

[0078] In some embodiments, a maximum time between an R2D transmission and the corresponding D2R transmission following it is determined based on one or more of the following factors:Devices’ timing capability: so that the following D2R transmission is with a good D2R timing obtained from the timing acquisition signal in the R2D transmission Energy storage: so that the device can transmit the following D2R transmission before the stored energy drains.

[0079] In some embodiments, if the duration between an R2D transmission and the corresponding D2R transmission exceeds a device’s timing capability due to time drifting. Additional R2D timing acquisition signal may be needed to keep a good timing before D2R transmission.

[0080] In some embodiments, between an R2D transmission and the corresponding D2R transmission following it, a timing acquisition signal can be transmitted without R2D data,called standalone timing acquisition signal. It can be transmitted together a preceding preamble.

[0081] In some embodiments, the standalone timing acquisition signal is transmitted at least TR2D_min ahead of the start of the following D2R transmission.

[0082] In some embodiments, the duration of R2D / D2R timing acquisition signal depends on the distance of the reader (e.g., network node 16) from the device (e.g., UE 22), as shown in FIG. 7. Here, the device closer to reader may need a shorter timing acquisition signal shown as TAI compared to the devices far away which require a longer timing acquisition signal shown as TA2.

[0083] In some embodiments, the length of timing acquisition signal for R2D and D2R transmission is the same.

[0084] In some embodiments, the length of timing acquisition signal for R2D and D2R transmission is different and it depends on the device synchronization capabilities i.e., the device (e.g., UE 22) may need larger R2D timing acquisition signal to acquire initial synchronization and the following D2R timing acquisition signal is smaller.

[0085] In some embodiments, the duration of R2D / D2R timing acquisition signal can also depend on the TR2Dmin, l.e., in cases where the device processing is slow the reader (e.g., network node 16) may allocate a larger TR2D_mm compared to devices with fast processing. The devices with slow processing may require longer timing acquisition signal and may additionally need standalone timing acquisition signal, while devices with fast processing might need shorter timing acquisition signal and may not need standalone timing acquisition signals. The relation of TR2D mm with the timing acquisition signal can be, e.g.:• TR2D min < X (Fast processing): Shorter timing acquisition signal similar to TAI shown in FIG. 7 may be enough.• x < TR?.D min < y (Medium processing): Longer timing acquisition signal similar to TA2 shown in FIG. 7 may be enough.• y < TR2D min (Slow processing): Longer timing acquisition signal similar to TA2 shown in FIG. 7 and standalone timing acquisition signal may be needed.Where, x and y can be defined by the reader (e.g., network node 16) alone or it can be negotiated by the reader and the device (e.g., UE 22).

[0086] A-IoT devices may require charging / energy harvesting gaps during an ongoing transmission. In some embodiments, a preamble / midamble is transmitted after the end of an energy harvesting gap to assist the A-IoT device (e.g., UE 22) in, e.g., regaining synchronization. In some embodiments, a delimiter is transmitted by the reader (e.g.network node 16) after the end of an energy harvesting gap to indicate to the A-IoT device (e.g., UE 22) the start of R2D transmission or to assist the A-IoT device in regaining coarse synchronization.

[0087] In some embodiments, a delimiter is transmitted by the A-IoT device (e.g., UE 22) after the end of an energy harvesting gap to indicate to the reader (e.g., network node 16) the start of D2R transmission or to assist the reader in acquiring coarse timing synchronization. In some embodiments, a preamble / midamble is transmitted after the end of an energy harvesting gap to assist the reader in, e.g., acquiring synchronization with the D2R signal.

[0088] In some embodiments, a delimiter is transmitted by the A-IoT device (e.g., UE 22) before the start of an energy harvesting gap / session to indicate to the reader (e.g., network node 16) that it needs to recharge or harvest energy. In some embodiments, a preamble / midamble is transmitted by the A-IoT device before the start of an energy harvesting gap / session to indicate to the reader that the A-IoT device may need to recharge or harvest energy.

[0089] In some embodiments, special delimiter / preamble / midamble sequences can be designed to indicate whether an energy harvesting gap is needed. Additionally, they may also indicate the estimated duration of the energy harvesting gap.For example, a special preamble / midamble is dedicated for indicating the need of an energy harvesting gap (e.g., to assist the reader (e.g., network node 16) in scheduling future messages) or requesting the reader to allow an energy harvesting gap. If the A-IoT device (e.g., UE 22) needs to take a break from transmitting / receiving D2R / R2D signals to replenish energy, it may insert this special preamble / midamble; otherwise, it may use the standard preamble / midamble.In another example, a set of N energy harvesting preambles / midambles is defined where each preamble in the set corresponds to an energy harvesting gap duration. For example, a set of 4 energy harvesting preambles / midambles is defined in the standard specification where the preambles / midambles indicate at least 4 unique energy harvesting gap durations: 1 sec, 10 sec, 20 sec, 50 sec. If the A-IoT device (e.g., UE 22) estimates the required energy harvesting gap to be closest to 10 sec, it may select and insert the third preamble / midamble in its D2R transmission to indicate to the reader that it will be harvesting energy for the next 10 sec after the start of the energy harvesting gap.

[0090] As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / orcomputer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0091] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0092] These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0093] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0094] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0095] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0096] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0097] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.NUMBERED EMBODIMENTS:Embodiment Al . A network node configured to communicate with a user equipment (UE), the network node configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to: transmit a first signal, the first signal including a first preamble, a first timing acquisition signal following the first preamble, and a first midamble; and communicate with the UE based on the first transmitted signal.Embodiment A2. The network node of Embodiment Al, wherein the network node is further configured to receive a second signal, the second signal including a second preamble, a second timing acquisition signal following the second preamble, and a second midamble.Embodiment A3. The network node of Embodiment A2, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the UE and an energy storage of the UE.Embodiment A4. The network node of Embodiment Al, wherein a duration of the timing acquisition signal is based on at least one of a processing time of the UE and a distance between the network node and the UE.Embodiment Bl. A method implemented in a network node that is configured to communicate with a user equipment, the method comprising: transmitting a first signal, the first signal including a first preamble, a first timing acquisition signal following the first preamble, and a first midamble; and communicating with the UE based on the first transmitted signal.Embodiment B2. The method of Embodiment Bl, further comprising receiving a second signal, the second signal including a second preamble, a second timing acquisition signal following the second preamble, and a second midamble.Embodiment B3. The method of Embodiment B2, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the UE and an energy storage of the UE.Embodiment B4. The method of Embodiment Bl, wherein a duration of the timing acquisition signal is based on at least one of a processing time of the UE and a distance between the network node and the UE.Embodiment Cl . A user equipment (UE) configured to communicate with a network node, the UE configured to, and / or comprising a radio interface and / or processing circuitry configured to: receive a first signal, the first signal including a first preamble, a first timing acquisition signal following the first preamble, and a first midamble; and communicate with the network node based on the first transmitted signal.Embodiment C2. The UE of Embodiment Cl, wherein the UE is further configured to transmit a second signal, the second signal including a second preamble, a second timing acquisition signal following the second preamble, and a second midamble.Embodiment C3. The UE of Embodiment C2, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the UE and an energy storage of the UE.Embodiment C4. The UE of Embodiment Cl, wherein a duration of the timing acquisition signal is based on at least one of a processing time of the UE and a distance between the network node and the UE.Embodiment DI . A method implemented in a user equipment (UE) that is configured to communicate with a network node, the method comprising: receiving a first signal, the first signal including a first preamble, a first timing acquisition signal following the first preamble, and a first midamble; and communicating with the network node based on the first transmitted signal.Embodiment D2. The method of Embodiment DI, further comprising transmitting a second signal, the second signal including a second preamble, a second timing acquisition signal following the second preamble, and a second midamble.Embodiment D3. The method of Embodiment D2, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the UE and an energy storage of the UE. Embodiment D4. The method of Embodiment DI, wherein a duration of the timing acquisition signal is based on at least one of a processing time of the UE and a distance between the network node and the UE.

Claims

CLAIMSClaim 1. A method implemented in a device for communication with a reader, the method comprising: receiving a first signal, the first signal including a first timing acquisition signal; and transmitting, in response to the first signal, a second signal, the second signal including a second timing acquisition signal.Claim 2. The method of Claim 1, wherein the first signal further includes a first data transmission and / or wherein the second signal further includes a second data transmission.Claim 3. The method of any of Claims 1-2, wherein the transmission of the second signal is paused for an energy harvesting gap.Claim 4. The method of Claim 3, wherein a first delimiter or first preamble or first midamble is transmitted or received after the end of the energy harvesting gap, before resuming transmission of the second signal.Claim 5. The method of any of Claims 3-4, wherein a second delimiter or second preamble or second midamble is transmitted after the pause of the transmission of the second signal, before the start of the energy harvesting gap.Claim 6. The method of Claim 5, wherein the second delimiter or second preamble or second midamble indicates, to the reader, that the energy harvesting gap is needed.Claim 7. The method of Claim 6, where the second delimiter or second preamble or second midamble further indicates a duration associated with the energy harvesting gap.Claim 8. The method of any of Claims 1-7, the method further comprising:receiving a third signal including a third timing acquisition signal, wherein the third signal is received after receiving the first signal and before transmitting the second signal.Claim 9. The method of Claim 8, wherein the third signal does not include data.Claim 10. The method of any of Claims 8-9, wherein the third signal is received at least a first time before transmitting the second signal, wherein the first time is based on a processing time of the device.Claim 11. The method of any of Claims 1-10, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the device and an energy storage of the device.Claim 12. The method of any of Claims 1-11, wherein the duration of the first and / or second timing acquisition is based on at least one of the device’s type and a capability of the device.Claim 13. A method implemented in a reader for communication with a device, the method comprising: transmitting a first signal, the first signal including a first timing acquisition signal; and receiving, in response to the first signal, a second signal, the second signal including a second timing acquisition signal.Claim 14. The method of Claim 13, wherein the first signal further includes a first data transmission and / or wherein the second signal further includes a second data transmission.Claim 15. The method of any of Claims 13-14, wherein the reception of the second signal is paused for an energy harvesting gap.Claim 16. The method of Claim 15, wherein a first delimiter or first preamble or first midamble is transmitted or received after the end of the energy harvesting gap, before resuming reception of the second signal.Claim 17. The method of any of Claims 15-16, wherein a second delimiter or second preamble or second midamble is received after the pause of the reception of the second signal, before the start of the energy harvesting gap.Claim 18. The method of Claim 17, wherein the second delimiter or second preamble or second midamble indicates that the energy harvesting gap is needed.Claim 19. The method of Claim 18, where the second delimiter or second preamble or second midamble further indicates a duration associated with the energy harvesting gap.Claim 20. The method of any of Claims 13-19, the method further comprising: transmitting a third signal including a third timing acquisition signal, wherein the third signal is transmitted after transmitting the first signal and before receiving the second signal.Claim 21. The method of Claim 20, wherein the third signal does not include data.Claim 22. The method of any of Claims 20-21, wherein the third signal is transmitted at least a first time before receiving the second signal, wherein the first time is based on a processing time of the device.Claim 23. The method of any of Claims 13-22, wherein a time between the first signal and the second signal is based on at least one of a timing capability of the device and an energy storage of the device.Claim 24. The method of any of Claims 13-23, wherein the duration of the first and / or second timing acquisition is based on at least one of the device’s type and a capability of the device.Claim 25. A device for communication with a reader, the device configured to, and / or comprising a radio interface and / or processing circuitry configured to: receive a first signal, the first signal including a first timing acquisition signal; and transmit, in response to the first signal, a second signal, the second signal including a second timing acquisition signal.Claim 26. The device of Claim 25, the device and / or radio interface and / or processing circuitry further configured to perform the method of any of claims 2-12.Claim 27. A reader for communication with a device, the reader configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to: transmit a first signal, the first signal including a first timing acquisition signal; and receive, in response to the first signal, a second signal, the second signal including a second timing acquisition signal.Claim 28. The reader of Claim 27, the reader and / or radio interface and / or processing circuitry further configured to perform the method of any of claim 14-24.

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