WO2026028004A1

WO2026028004A1 - Adaptive midamble

Info

Publication number: WO2026028004A1
Application number: PCT/IB2025/057309
Authority: WO
Inventors: Oana-Elena Barbu; Nuno Manuel KIILERICH PRATAS; Benny Vejlgaard; Simon Svendsen; Johannes Harrebek
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2024-07-29
Filing date: 2025-07-18
Publication date: 2026-02-05
Anticipated expiration: 2027-01-29
Also published as: GB202411066D0

Abstract

Example embodiments of the present disclosure are directed to methods, devices, apparatuses and computer readable storage medium for adaptive midamble. A method comprises receiving, from a third apparatus, first configuration information indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmitting, based on the first configuration information, the frame with the first frame format to the second apparatus.

Description

ADAPTIVE MIDAMBLE

CROSS-REFERENCE TO RELATED APPLICATION

[0001 ] This application claims priority from, and the benefit of, Great Britain Application No 2411066.0, filed July 29, 2024, which is hereby incorporated by reference in its entirety.

FIELDS

[0002] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for adaptive midamble.

BACKGROUND

[0003] In current study item (SI) radio access network 1 (RAN1) on ambient internet of things (A-IOT) frame structure, it is being discussed the usage of a midamble in the device to reader (D2R) signal, i.e. signal sent by the A-IOT device to the reader. The midamble may act as a reference signal and may not only help the reader to estimate the tag channel and total interference, but also to resynchronize to the A-IOT device transmission.

SUMMARY

[0004] I n a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmit, based on the first message, the frame with the first frame format to the second apparatus.

[0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and receive, based on the first message, the frame with the first frame format from the first apparatus. [0006] In a third aspect of the present disclosure, there is provided a third apparatus. The third apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble. [0007] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmitting, based on the first message, the frame with the first frame format to the second apparatus.

[0008] In a fifth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and receiving, based on the first message, the frame with the first frame format from the first apparatus.

[0009] In a sixth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0010] In a seventh aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for transmitting, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for transmitting, based on the first message, the frame with the first frame format to the second apparatus.

[0011] In an eighth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for receiving, based on the first message, the frame with the first frame format from the first apparatus.

[0012] In a ninth aspect of the present disclosure, there is provided a third apparatus. The third apparatus comprises means for receiving, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0013] In a tenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fourth aspect.

[0014] In an eleventh aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fifth aspect.

[0015] In a twelfth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the sixth aspect.

[0016] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0018] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0019] FIG. 2 illustrates a structure of D2R frame according to some example embodiments of the present disclosure;

[0020] FIG. 3 and FIG. 4 illustrate example structures of D2R frame according to some example embodiments of the present disclosure;

[0021] FIG. 5A to FIG. 5C illustrate signaling flows of communication according to some example embodiments of the present disclosure;

[0022] FIG. 6 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0023] FIG. 7 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0024] FIG. 8 illustrates a flowchart of a method implemented at a third apparatus in accordance with some example embodiments of the present disclosure;

[0025] FIG. 9 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0026] FIG. 10 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0027] FIG. 11 illustrates a flowchart of a method implemented at a third apparatus in accordance with some example embodiments of the present disclosure;

[0028] FIG. 12 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0029] FIG. 13 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0030]Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

[0031] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0032] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0033] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0034] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

[0035]As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0036]As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0037]The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. 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”, “has”, “having”, “includes” and/or “including”, when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof. [0038] As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable):

(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0039]This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0040] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE- A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-loT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1 G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), the sixth generation (6G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0041] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (I AB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0042]The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0043] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and/or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0044] The term “transmission reception point (TRP)” used herein may be defined as an antenna array, with one or more antenna elements, available to the network located at a specific geographical location for a specific area. In some embodiments, the TRP may be implemented at a network device. The term “condition registered in a network side” used herein may refer to a condition at network side which include additional information to assist terminal units to improve consistency between training and inference model. The term “condition registered in a network side”, the term “condition registered in a second apparatus” and the term “network (NW) side additional condition” may be used interchangeable. The process of model identification pinpoints what are known as “additional conditions”, which may include, for example, training dataset category, site-related information, timestamps, implicit identification information (such as, labels for specific gNB/UE implementation details), statistical information (e.g., delay spread, angular spread, line of sight (LOS)ZNone-LOS data and so on), and other factors. The term “condition registered in a UE side” used herein may refer to a condition at UE side which include additional information to improve consistency between training and inference model. The term “condition registered in a UE side”, the term “condition registered in a first apparatus” and the term “UE side additional condition” may be used interchangeable.

[0045] For reader to device (R2D) transmission, if orthogonal frequency division multiplexing (OFDM)- based waveform is used, the start of R2D transmission from reader perspective is assumed to be aligned with the boundary of a new radio (NR) OFDM symbol (including the cyclic prefix, CP) for in- band/guard-band operation.

[0046] To determine or derive the end of physical reader to device channel (PRDCH) transmission, at least following options may be studied: Option 1 : R2D postamble immediately follows the PRDCH to indicate the end of the PRDCH; Option 2: Based on R2D control information.

[0047] For the reader to acquire the end of physical device to reader channel (PDRCH) transmission, at least following options may be studied: Option 1 : device to reader (D2R) postamble immediately follows the PDRCH; Option 2: Based on control information.

[0048] For D2R transmission, it has been agreed to study the necessity of midamble at least for the purpose of performing timing/frequency tracking or channel estimation or interference estimation, considering at least the following: modulation and coding schemes (e.g., data modulation, line/channel coding), receiving methods (e.g., coherent or non-coherent), D2R transmission length/packet size, midamble overhead, timing/frequency accuracy and phase accuracy.

[0049] It has been agreed that the R2D transmission without midamble may be studied as the baseline if Manchester encoding is used. Further, if Pulse Interval Encoding (PIE) is used, the R2D transmission with midamble may be performed or not.

[0050] In an A-loT communication, in some cases, the A-loT device transmits/reflects D2R signal to the reader. Backscatter type A-loT devices (type 1 and 2a) cannot generate an RF signal and thus RF signal needs be provided externally. The carrier wave (CW) node (which may/may not be collocated with the activator) may provide the RF carrier for the A-loT D2R (this RF carrier is referred to as Carrier Wave-2-AloT Device signal (CW2D) signal. The A-loT Device will modulate its response data onto the reflection of the CW2D thereby forming the D2R signal. An A-loT reader may transmit reader to device (R2D) signal to the A-loT device via PRDCH, while the A-loT device may transmit device to reader (D2R) signal to the A-loT reader via PDRCH.

[0051] As discussed above, in current study item SI RAN1 on ambient internet of things (A-IOT) frame structure, the usage of a midamble in the D2R signal is being discussed, i.e., a midample in signal sent by the A-IOT device to the reader. The loT reader may detect and read the D2R signal. Generally speaking, the usage of the midamble, although easing the reading task, it complicates the D2R signal generation and introduces both spectral and energy overhead since: the midamble is a known sequence and carrying no data, and the midamble generation consumes additional energy from the A-IOT device.

[0052] In order to at least address the above problems, example embodiments of the present disclosure are directed to methods, devices, apparatuses and computer readable storage medium for adaptive midamble. A method comprises receiving, at a first apparatus (such as, an loT device) and from a third apparatus (such as, a network), first configuration information indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmitting, based on the first configuration information, the frame with the first frame format to the second apparatus.

[0053] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

Example Environment

[0054] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, the first apparatus 110, the second apparatus 120, the network apparatus 130 and an activator 140 (also may be called as loT activation, which may be a terminal device or a network device) may communicate with each other. [0055] In some example embodiments, the first apparatus 110 may be an A-loT device, the second apparatus 120 may be an A-loT reader (such as, a terminal device or a network device, sometimes referred to as a reader for brevity). The network apparatus 130 may and/the activator 140 may communicate with the A-loT device and A-loT reader. Specifically, the network apparatus 130 may configure the AloT device via the Activator. In operation, all the communication and configuration towards the AloT device are transmitted via the Activator

[0056] As used herein, either the network apparatus 130 or the activator 140 may be called as a third apparatus. Further, both the second apparatus 120 and the activator 140 may act/be called as a reader. [0057] In some example embodiments, a link from a network apparatus to a terminal apparatus is referred to as a downlink (DL), and a link from a terminal apparatus to a network apparatus is referred to as an uplink (UL). In DL, the network apparatus is a transmitting (TX) device (or a transmitter) and the terminal apparatus is a receiving (RX) device (or a receiver). In UL, the terminal apparatus is a TX device (or a transmitter) and the network apparatus is a RX device (or a receiver). Channels for UL transmission include but are not limited to, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH) and so on, and channels for DL transmission include but are not limited to, physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH) and so on.

[0058] Further, two network devices may communicate with each other via X2/Xn interface, while two terminal devices may communicate with each other via PC5/sidelink interface. Channel used for the communication from an A-loT device to an activation reader may be PDRCH/D2R, while channel used for the communication from an activation reader to an A-loT device may be PRDCH/R2D. In summary, according to the specific type of the communication peers, proper channel may be determined.

[0059] It is to be understood that the number of apparatuses is only for the purpose of illustration without suggesting any limitations. The communication environment 100 may include any suitable apparatuses and cells adapted for implementing embodiments of the present disclosure. Although not shown, it is to be understood that one or more additional second devices may be located in the respective cells. It would also be appreciated that in some examples, only the homogeneous network deployment or only the heterogeneous network deployment may be included in the communication environment 100.

[0060] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1 G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple- Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future. l/l/br Principle and Example Signaling for Communication

[0061]The midamble acts as a reference signal and may help the reader not only to estimate the tag/A-loT channel and total interference (if the target signal is in a given interference plus noise ratio (SINR) range), but also to resynchronize to the A-IOT device transmission (in the case where this transmission is very long, e.g. in the order of 1s or more).

[0062] FIG. 2 illustrates a structure of D2R frame 200 according to some example embodiments of the present disclosure. As illustrated in FIG. 2, a midamble is placed, as the name suggests, in the middle of the D2R frame. According to some example embodiments of the present disclosure, a solution of adaptive midamble in D2R frame is proposed.

[0063] Before discussing the example processes of the present disclosure, details on the D2R frame formats introduced by the present disclosure will be discussed first.

[0064] According to the present disclosure, a plurality of frame formats/types (also may be referred to as different midamble formats/types) may be supported. In some example embodiments, the plurality of frame formats may be predefined, such as, by the wireless standards (e.g., 3GPP), the service provider or the network operator. In some other example embodiments, different frame formats may be implemented as dynamically configurated (such as, by the NW).

[0065] According to the present disclosure, the plurality of frame formats may comprise a first frame format and a second frame format. Further, the second frame format may be different from the first frame format in terms of a number of symbols comprised in a midamble. As one example, a first midamble associated with the first frame format comprises a first number of symbols (e.g., 20 symbols), while a second midamble associated with the second frame format comprises a second number of symbols (e.g., 40 symbols). It should be noted that generally speaking, there may be a mapping among the number of symbols and a duration. In view of this, wordings “the number of symbols” and “duration” may be used interchangeably.

[0066] Alternatively, or in addition, the second frame format may be different from the first frame format in terms of a symbol sequence of a midamble. As one example, a first midamble associated with the first frame format consists of a first symbol sequence, while a second midamble associated with the second frame format consists of a different second symbol sequence.

[0067] Alternatively, or in addition, the second frame format may be different from the first frame format in terms of a modulation scheme of a midamble. As one example, a first midamble associated with the first frame format is coded with a line coding, while a second midamble associated with the second frame format is coded with a Manchester coding.

[0068] Merely for better understanding, to support a dynamic activation of a variable-sized midamble, the following D2R frame formats may be defined:

• Format 0 may mean that no midamble is to be used.

• Format 1 may mean that a midamble of a first size is to be used. The first size may refer to the number of samples of the midamble, (optionally, assuming the modulation of the midamble is fixed and known in advance e.g. line coding, Manchester coding and so on).

• Format k may mean that a midamble of the k^th size is used.

[0069] Further, Formats 1 to k may be identified by respective identities (indices) as below:

• Identity 0: Preamble, data, postamble;

• Identity 1 : Preamble, data, midamble of a first size, data, postamble;

• Identity k: Preamble, data, midamble of the k^th size, data, postamble, k is an integer.

[0070] Further, in addition to the midamble size (i.e., the number of symbols comprised in the midamble), the midamble modulation and/or bit sequence also may be subject to change as well. In view of this, the frame format definition (e.g. a midamble definition) may at least include at least one of the following: midamble modulation, midamble size, or midamble sequence (which may be an index for a set of known orthogonal sequences).

[0071] In the following, details about how to construct the frame with an adaptive midamble will be discussed.

[0072] In some example embodiments, the first apparatus 110 may generate the frame based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame (a fixed duration).

[0073] In one embodiment, the duration of the different D2R frame formats may be the same (e.g., to ensure coexistence between different formats in frequency in the same time instance), while what it changes is on how the symbols are mapped in the frame.

[0074] In some example embodiments, in a case of a fixed D2R frame duration (i.e., the pre-defined number and/or the pre-defined duration), the inclusion of a midamble may be done by puncturing the data symbols (i.e. effectively decreasing the code rate)

[0075] Specifically, the first apparatus 110 may generate a frame with a first frame format (e.g., frame N1 ) based on the pre-defined number and/or the pre-defined duration, and also may generate a frame with a second frame format (e.g., frame N2) based on the pre-defined number and/or the pre-defined duration.

[0076] In this event, a first number of symbols comprised in the frame with the first frame format (e.g., frame N1) is the same as a second number of symbols comprised in a frame with a second frame format (e.g., frame N2). Alternatively, a first duration of the frame with the first frame format (e.g., frame N1 ) is the same as a second duration of the frame with the second frame format (e.g., frame N2).

[0077] Reference is now made to FIG. 3, which illustrates example structures 300 of a D2R frame according to some example embodiments of the present disclosure. In the example of FIG. 3, frame formats 310 to 340 are associated with a fixed D2R frame duration/the pre-defined number and/or the pre-defined duration.

[0078] Alternatively, in some other embodiments, the duration of the D2R formats increases with the addition of the midamble. That is, the adaptive D2R frame duration may be applied, where the inclusion of a midamble may be done by adding additional symbols (the data symbols are not punctured).

[0079] For example, in some example embodiments, the first apparatus 110 may generate the frame with the first frame format (e.g., frame N1 ) by incorporating a first midamble associated with the first frame format into a frame, and also may generate the frame with the second frame format (e.g., frame N2) by incorporating a second midamble associated with the second frame format into a frame.

[0080] In this event, a first number of symbols comprised in the frame with the first frame format (e.g., frame N1 ) is different from a second number of symbols comprised in the frame with the second frame format (e.g., frame N2) which is generated based on a second midamble associated with the second frame format. Alternatively, a first duration of the frame with the first frame format (e.g., frame N1 ) is different from a second duration of the frame with the second frame format (e.g., frame N2) which is generated based on the second midamble associated.

[0081] Reference is now made to FIG. 4, which illustrates example structures 400 of a D2R frame according to some example embodiments of the present disclosure. In the example of FIG. 4, frame formats 410 to 440 are associated with different frame durations.

[0082] In particular, it is important that the increase in the D2R frame duration is done in such a way that coexistence in frequency is still possible. For example, in one implementation, a minimum D2R frame duration may be assumed, and the inclusion of a midamble corresponds to doubling the size of the corresponding D2R frame.

[0083] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame. Alternatively, a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0084] In the example of FIG. 4, the duration of frame format 410 is the same as the minimum duration, the duration of frame format 420 is twice as long as the minimum duration, the duration of frame format 430 is three times as long as the minimum duration, and the duration of frame format 440 is four times as long as the minimum duration.

[0085] After discussion on the frame formats, how to configure/activate/update the frame format will be discussed.

[0086] According to the present disclosure, the third apparatus 130 (such as, an NW) may configure a specific frame format to be used in the A-loT communication. In summary, the third apparatus 130 may decide and configure whether to activate (or deactivate/reconfigure) the D2R midamble type and/or size and/or modulation scheme and/midamble sequence.

[0087] Additionally, the third apparatus 130 may make the decision based at least on the expected level of interference and expected payload of the D2R signal. In one example embodiment, the third apparatus 130 may assess the channel and/or interference conditions e.g. based on at least one of the following: the last reading outcome, other A-IOT device readings (where said devices are expected to be in the proximity of the target device), or the reader past feedback regarding its own perceived SINR levels and so on.

[0088] In one example embodiments, depending on the A-IOT device type and application for which it has been deployed, the third apparatus 130 also may estimate a D2R payload size. In some example embodiments, the third apparatus 130 may assume a smaller payload if the device is of a first type (such as, type 1). Alternatively, the third apparatus 130 may assume a larger payload if the device is of a second type (such as, type 2b) and is capable of also collect and store extrinsic information such as sensor information.

[0089]The determined frame format may be communicated both to the A-IOT device (via such as PRDCH) and to the readers, via an appropriate interface (e.g., if the reader is another NW node, then it can be done via X2/Xn interface, while if the reader is a UE, then it can be done via PDSCH, Uu or PC5 interface and so on) which depends on the device type of the third apparatus 130/activator and the second apparatus 120/reader.

[0090] In some example embodiments, the configuration may explicitly indicate the determined frame format via such as a control or data field in the PRDCH, e.g., via an activation flag and a midamble duration variable.

[0091] Alternatively, the configuration may implicitly indicate the determined frame format via an identity/index pointing to a D2R frame format to be used by the A-IOT device.

[0092] Further example signalling interaction processes will be discussed with reference to FIG. 5A, which illustrates a signaling flow 500A of communication according to some example embodiments of the present disclosure.

[0093] In operation, the third apparatus 130 may determine, from the plurality of frame formats, a first frame format is to be applied to a frame to be transmitted from the first apparatus 110 to the second apparatus 120. The third apparatus 130 would inform the first frame format to the first apparatus 110 and the second apparatus 120.

[0094] As illustrated in FIG. 5A, the third apparatus 130 transmits (510-1) the first configuration information indicating the first frame format to the first apparatus 110, and the first apparatus 110 receives (510-2) the first configuration information accordingly.

[0095] Details about the first configuration information are discussed in the following. In some example embodiments, the first configuration information may comprise at least one of the following:

• an indication of a number of symbols comprised in a midamble of the frame with the first frame format,

• an indication of a symbol sequence of the midamble, or

• an indication of a modulation scheme of the midamble.

[0096] Alternatively, in some example embodiments, the plurality frame formats may be identified by a plurality of respective format identities, and the first configuration information may comprise a respective format identity of the first frame format.

[0097] In some example embodiments, the first configuration information may be transmitted via a physical reader to device channel (PRDCH) which depends on the device type of the third apparatus 130/activator and the second apparatus 120/reader.

[0098] Further refer to FIG. 5A. The third apparatus 130 transmits (520-1 ) the second configuration information indicating the first frame format to the second apparatus 120, and the second apparatus 110 receives (520-2) the second configuration information accordingly. It is noted that the transmission of the second configuration information may be performed prior to or after the transmission of the first configuration information.

[0099] Details about the second configuration information are discussed in the following.

[0100] In some example embodiments, the second configuration information may comprise at least one of the following:

• an indication of a symbol sequence of the midamble, or

• an indication of a modulation scheme of the midamble.

[0101] In some example embodiments, the plurality frame formats may be identified by a plurality of respective format identities, and the second configuration information may comprise a respective format identity of the first frame format.

[0102] In some example embodiments, the second configuration information may be transmitted via a physical uplink shared channel (PDSCH), a PC5 interface or an X2/Xn interface, which depends on the device type of the third apparatus 130/activator and the second apparatus 120/reader.

[0103]Then, the first apparatus 110 transmit (530-1), based on the first configuration information, the frame with the first frame format to the second apparatus 120. Accordingly, the second apparatus 120 receives (530-2), based on the second configuration information, the frame with the first frame format.

[0104] Example processes where the activator is involved are briefly discussed as below will be discussed with reference to FIG. 5C.

[0105] In operation, (using the above assessment) the NW may select the D2R frame format and configure the reading session by informing which D2R frame type is to be activated at the A-IOT. It is assumed that the activator (also named R2D reader in 3GPP) is the radio which may transmit directly to the A-IOT device. The activator may be a NW node, or another UE. In the former case, the configuration of D2R frame type is done via a new information element (IE) sent over X2/Xn interface or alternatively new radio positioning protocol A (NRPPa) (if the NW element is the location management function (LMF)). In the latter case, the configuration is done via DL PDSCH or via location positioning protocol (LPP). The reader may be similarly informed about the D2R frame format it should expect from the A-IOT device, via the second configuration information as discussed above.

[0106]The activator may activate the A-IOT device via the R2D signal, to which it appends a new IE (e.g. in the control or data part of the PRDCH channel) configuring the D2R frame type.

[0107] As a result, the A-IOT device is activated and generates a D2R signal using the configured frame type (e.g. frame type X in the FIG. 5C).

[0108] According to the present disclosure, the first apparatus 110 (A-loT device) may request a specific frame format to be used in the A-loT communication. In summary, the A-IOT device may request in advance a midamble change/update. For example, when transmitting D2R frame N, the device may request the activation (or deactivation/change) in midamble duration for the D2R frame N+1.

[0109] In some example embodiments, the request (also referred to as a first message sometimes) may explicitly indicate the activation (or deactivation/change/update) via a data field in the PDRCH. Alternatively, in some example embodiments, the request may implicitly indicate the activation (or deactivation/change) via the index/identity of the frame format.

[0110] In some example embodiments, the request may additionally contain a reason for requesting the activation (or deactivation/change/update), e.g., a flag indicating either a large future payload, or a large amount of interference detected on the R2D signal.

[0111] Additionally, this request may be sent to the reader, and then the reader may forward the request (also referred to as a second message) to the NW via the appropriate interface (e.g. X2/Xn, PUSCH, Uu or PC5 interface).

[0112] Such signalling interaction processes will be discussed with reference to FIG. 5B, which illustrates a signaling flow 500B of communication according to some example embodiments of the present disclosure.

[0113] In operation, the first apparatus 110 may determine, from the plurality of frame formats, a first frame format is to be applied to a frame to be transmitted from the first apparatus 110 to a second apparatus 120. The first apparatus 110 would request to apply the first frame format.

[0114] As illustrated in FIG. 5B, the first apparatus 110 transmits (550-1) a first message indicating the first frame format to the second apparatus 120. Details about the first message are discussed in the following.

[0115] In some example embodiments, the first message comprises at least one of the following:

• an indication of a symbol sequence of the midamble, or

• an indication of a modulation scheme of the midamble.

[0116] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

[0117] In some example embodiments, the first message is transmitted via a physical device to reader channel (PDRCH), which depends on the device type of the first apparatus 110/A-loT device and the second apparatus 120/reader.

[0118] Additionally, after receiving the first message, the second apparatus 120 may need to inform the third apparatus 130 that the first frame format will be applied. Alternatively, after receiving the first message, the second apparatus 120 may request a permission/grant from the third apparatus 130. The third apparatus 130 may decide whether to grant the request or not in upcoming TX N+1 .

[0119] As illustrated in FIG. 5B, the second apparatus 120 may generate a second message indicating the first frame format, and then may transmit (560-1) the second message to the third apparatus 130 which is serving the first apparatus 110 and second apparatus 120. The third apparatus 130 may receive (560-2) the second message accordingly.

[0120] In example of FIG. 5C, the A-IOT device may proactively request for the next transmission a new frame type. For example, in a case that the A-IOT device expects a larger payload or has detected high interference. The request may be sent via a new IE in the D2R signal (e.g. request frame type Z in the figure). The reader receives the D2R signal of frame type X, and detects the data and the reconfiguration request (i.e. to switch to frame type Z). Then the reader may optionally forward this request to the NW entity.

[0121] In this way, the A-loT device may communicate with the reader with the requested frame format. The adaptive midamble may decrease the interference and enhance the communication performance. [0122] It should be noted that the NW and the A-loT device may update the frame format alternately. In other words, the above discussed processed may be implemented in combination.

[0123] Reference is now made to FIG. 5C, which illustrates a signaling flow 500C of communication according to some example embodiments of the present disclosure.

[0124] At Step 580, the NW assess channel and interference conditions and/or estimate D2R payload size, and then choose D2R frame format X. At Step 582, the reader is configured with the D2R frame type X (for TX N). At Step 584, the A-loT device is configured with the D2R frame type X (for TX N). At Step 586, the A-loT device, at TX N, transmit the D2R signal with format X, and further the D2R signal comprise an loT device request to apply the frame type Z at TX N+1 .

[0125] At the Step 588, the reader may forward the reconfiguration request for D2R TX N+1 to the NW. As a result, the A-loT device, at TX N + 1 , transmits the D2R signal with format Z.

[0126] Although not shown in FIG. 5C. In some embodiment, the reader may transmit a request about whether the format Z may be applied at TX N + 1 to the NW. The NW may make the decision. If the NW allows to apply the format Z at TX N + 1 , the A-loT device, at TX N + 1, transmits the D2R signal with format Z.

Example Methods

[0127] FIG. 6 shows a flowchart of an example method 600 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0128] At block 610, the first apparatus 110 receives, from a third apparatus, first configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0129] At block 620, the first apparatus 110 transmits, based on the first configuration information, the frame with the first frame format to the second apparatus. [0130] In some example embodiments, the first configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0131] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first configuration information comprises a respective format identity of the first frame format.

[0132] In some example embodiments, the method 600 further comprises: generating the frame with the first frame format based on a pre-defined number of symbols comprised in a frame and/or a predefined duration of a frame.

[0133] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0134] In some example embodiments, the method 600 further comprises: generating the frame with the first frame format by incorporating a first midamble associated with the first frame format into a frame.

[0135] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with the second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0136] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0137] In some example embodiments, the first configuration information is transmitted via a physical reader to device channel (PRDCH) and the frame is a device to reader (D2R) frame.

[0138] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0139] FIG. 7 shows a flowchart of an example method 700 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0140] At block 710, the second apparatus 120 receives, from a third apparatus, second configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0141]At block 720, the second apparatus 120 receives, based on the second configuration information, the frame with the first frame format from the first apparatus.

[0142] In some example embodiments, the second configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0143] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the second configuration information comprises a respective format identity of the first frame format.

[0144] In some example embodiments, the frame with the first frame format is generated based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0145] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0146] In some example embodiments, the frame with the first frame format is generated by incorporating a first midamble associated with the first frame format into a frame.

[0147] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with a second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0148] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0149] In some example embodiments, the second configuration information is transmitted via a physical uplink shared channel (PDSCH) if the second apparatus 120 is a UE, a PC5 interface or an X2/Xn interface, and the frame is a device to reader (D2R) frame.

[0150] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0151] FIG. 8 shows a flowchart of an example method 800 implemented at a third apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the third apparatus 130 in FIG. 1.

[0152] At block 810, the third apparatus 130 transmits, to a first apparatus, first configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0153] At block 820, the third apparatus 130 transmits, to the second apparatus, second configuration information indicating the first frame format.

[0154] In some example embodiments, the first and/or the second configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0155] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first and/or the second configuration information comprises a respective format identity of the first frame format.

[0156] In some example embodiments, the first configuration information is transmitted via a physical reader to device channel (PRDCH), the second configuration information is transmitted via a physical downlink shared channel (PDSCH), a PC5 interface or an X2/Xn interface, and the frame is a device to reader (D2R) frame.

[0157] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0158] FIG. 9 shows a flowchart of an example method 900 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0159] At block 910, the first apparatus 110 transmits, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0160] At block 920, the first apparatus 110 transmits, based on the first message, the frame with the first frame format to the second apparatus.

[0161] In some example embodiments, the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0162] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

[0163] In some example embodiments, the method 900 further comprises: generating the frame with the first frame format based on a pre-defined number of symbols comprised in a frame and/or a predefined duration of a frame.

[0164] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0165] In some example embodiments, the method 900 further comprises: generating the frame with the first frame format by incorporating a first midamble associated with the first frame format into a frame.

[0166] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with the second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0167] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0168] In some example embodiments, the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

[0169] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, and the second apparatus is an loT reader.

[0170] FIG. 10 shows a flowchart of an example method 1000 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0171] At block 1010, the second apparatus 120 receives, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0172] At block 1050, the second apparatus 120 receives, based on the first message, the frame with the first frame format from the first apparatus.

[0173] In some example embodiments, the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0174] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

[0175] In some example embodiments, the frame with the first frame format is generated based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0176] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration. [0177] In some example embodiments, the frame with the first frame format is generated by incorporating a first midamble associated with the first frame format into a frame.

[0178] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with a second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0179] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0180] In some example embodiments, the method 1000 further comprises: generating a second message indicating the first frame format; and transmitting the second message to a third apparatus serving the first and second apparatuses.

[0181] In some example embodiments, the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

[0182] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0183] FIG. 11 shows a flowchart of an example method 1100 implemented at a third apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of the third apparatus 130 in FIG. 1.

[0184] At block 1110, the third apparatus 130 receives, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

[0185] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

Example Apparatus, Device and Medium

[0186] In some example embodiments, a first apparatus capable of performing any of the method 600 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1 .

[0187] In some example embodiments, the first apparatus comprises means for receiving, from a third apparatus, first configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for transmitting, based on the first configuration information, the frame with the first frame format to the second apparatus.

[0188] In some example embodiments, the first configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0189] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first configuration information comprises a respective format identity of the first frame format.

[0190] In some example embodiments, the first apparatus further comprises: means for generating the frame with the first frame format based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0191] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0192] In some example embodiments, the first apparatus further comprises: means for generating the frame with the first frame format by incorporating a first midamble associated with the first frame format into a frame.

[0193] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with the second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0194] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0195] In some example embodiments, the first configuration information is transmitted via a physical reader to device channel (PRDCH) and the frame is a device to reader (D2R) frame.

[0196] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0197] In some example embodiments, a second apparatus capable of performing any of the method 700 (for example, the second apparatus 120 in FIG. 1 ) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0198] In some example embodiments, the second apparatus comprises means for receiving, from a third apparatus, second configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for receiving, based on the second configuration information, the frame with the first frame format from the first apparatus.

[0199] In some example embodiments, the second configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0200] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the second configuration information comprises a respective format identity of the first frame format.

[0201] In some example embodiments, the frame with the first frame format is generated based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0202] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0203] In some example embodiments, the frame with the first frame format is generated by incorporating a first midamble associated with the first frame format into a frame.

[0204] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with a second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0205] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0206] In some example embodiments, the second configuration information is transmitted via a physical downlink shared channel (PDSCH), a PC5 interface or an X2/Xn interface, and the frame is a device to reader (D2R) frame.

[0207] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0208] In some example embodiments, a third apparatus capable of performing any of the method 800 (for example, the third apparatus 130 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The third apparatus may be implemented as or included in the third apparatus 130 in FIG. 1 .

[0209] In some example embodiments, the third apparatus comprises means for transmitting, to a first apparatus, first configuration information indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to a second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for transmitting, to the second apparatus, second configuration information indicating the first frame format. [0210] In some example embodiments, the first and/or the second configuration information comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0211] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first and/or the second configuration information comprises a respective format identity of the first frame format.

[0212] In some example embodiments, the first configuration information is transmitted via a physical reader to device channel (PRDCH), the second configuration information is transmitted via a physical downlink shared channel (PDSCH), a PC5 interface or an X2/Xn interface, and the frame is a device to reader (D2R) frame.

[0213] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0214] In some example embodiments, a first apparatus capable of performing any of the method 900 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1 .

[0215] In some example embodiments, the first apparatus comprises means for transmitting, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for transmitting, based on the first message, the frame with the first frame format to the second apparatus.

[0216] In some example embodiments, the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0217] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format. [0218] In some example embodiments, the first apparatus further comprises: means for generating the frame with the first frame format based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0219] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0220] In some example embodiments, the first apparatus further comprises: means for generating the frame with the first frame format by incorporating a first midamble associated with the first frame format into a frame.

[0221] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with the second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0222] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0223] In some example embodiments, the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

[0224] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, and the second apparatus is an loT reader.

[0225] In some example embodiments, a second apparatus capable of performing any of the method 1000 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0226] In some example embodiments, the second apparatus comprises means for receiving, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and means for receiving, based on the first message, the frame with the first frame format from the first apparatus.

[0227] In some example embodiments, the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

[0228] In some example embodiments, the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

[0229] In some example embodiments, the frame with the first frame format is generated based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

[0230] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

[0231] In some example embodiments, the frame with the first frame format is generated by incorporating a first midamble associated with the first frame format into a frame.

[0232] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with a second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated. [0233] In some example embodiments, a first number of symbols comprised in the frame with the first frame format is a multiple of a pre-defined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

[0234] In some example embodiments, the second apparatus further comprises: means for generating a second message indicating the first frame format; and means for transmitting the second message to a third apparatus serving the first and second apparatuses.

[0235] In some example embodiments, the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

[0236] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0237] In some example embodiments, a third apparatus capable of performing any of the method 1100 (for example, the third apparatus 130 in FIG. 1) may comprise means for performing the respective operations of the method 1100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The third apparatus may be implemented as or included in the third apparatus 130 in FIG. 1.

[0238] In some example embodiments, the third apparatus comprises means for receiving, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats. The first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus. The plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble. [0239] In some example embodiments, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

[0240] FIG. 12 is a simplified block diagram of a device 1200 that is suitable for implementing example embodiments of the present disclosure. The device 1200 may be provided to implement a communication device, for example, the first apparatus 110, the second apparatus 120 or the third apparatus 130 as shown in FIG. 1 . As shown, the device 1200 includes one or more processors 1210, one or more memories 1220 coupled to the processor 1210, and one or more communication modules 1240 coupled to the processor 1210.

[0241]The communication module 1240 is for bidirectional communications. The communication module 1240 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1240 may include at least one antenna.

[0242] The processor 1210 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1200 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0243]The memory 1220 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1224, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1222 and other volatile memories that will not last in the power-down duration.

[0244] A computer program 1230 includes computer executable instructions that are executed by the associated processor 1210. The instructions of the program 1230 may include instructions for performing operations/acts of some example embodiments of the present disclosure. The program 1230 may be stored in the memory, e.g., the ROM 1224. The processor 1210 may perform any suitable actions and processing by loading the program 1230 into the RAM 1222.

[0245]The example embodiments of the present disclosure may be implemented by means of the program 1230 so that the device 1200 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 11. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0246] In some example embodiments, the program 1230 may be tangibly contained in a computer readable medium which may be included in the device 1200 (such as in the memory 1220) or other storage devices that are accessible by the device 1200. The device 1200 may load the program 1230 from the computer readable medium to the RAM 1222 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e. , tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0247] FIG. 13 shows an example of the computer readable medium 1300 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1300 has the program 1230 stored thereon.

[0248] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0249] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machineexecutable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0250] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0251] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0252]The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. [0253] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable subcombination.

[0254] Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

I/We Claim:

1 . A first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmit, based on the first message, the frame with the first frame format to the second apparatus.

2. The first apparatus of claim 1 , wherein the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

3. The first apparatus of claim 1 , wherein the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

4. The first apparatus of any of claims 1 to 3, wherein the first apparatus is caused to: generate the frame with the first frame format based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

5. The first apparatus of claim 4, wherein, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

6. The first apparatus of any of claims 1 to 3, wherein the first apparatus is caused to: generate the frame with the first frame format by incorporating a first midamble associated with the first frame format into a frame.

7. The first apparatus of claim 6, wherein, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with the second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated.

8. The first apparatus of claims 6 or 7, wherein, a first number of symbols comprised in the frame with the first frame format is a multiple of a predefined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

9. The first apparatus of any of claims 1 to 8, wherein the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

10. The first apparatus of any of claims 1-9, wherein the first apparatus is an ambient internet of things (A-loT) device, and the second apparatus is an loT reader.

11 . A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and receive, based on the first message, the frame with the first frame format from the first apparatus.

12. The second apparatus of claim 11 , wherein the first message comprises at least one of the following: an indication of a number of symbols comprised in a midamble of the frame with the first frame format, an indication of a symbol sequence of the midamble, or an indication of a modulation scheme of the midamble.

13. The second apparatus of claim 11 , wherein the plurality frame formats are identified by a plurality of respective format identities, and the first message comprises a respective format identity of the first frame format.

14. The second apparatus of any of claims 11 to 13, wherein the frame with the first frame format is generated based on a pre-defined number of symbols comprised in a frame and/or a pre-defined duration of a frame.

15. The second apparatus of claim 14, wherein, a first number of symbols comprised in the frame with the first frame format is the same as a second number of symbols comprised in a frame with a second frame format which is generated based on a second midamble associated with the second frame format and the pre-defined number, or a first duration the frame with the first frame format is the same as a second duration of the frame with the second frame format which is generated based on the second midamble and the pre-defined duration.

16. The second apparatus of any of claims 11 to 13, wherein the frame with the first frame format is generated by incorporating a first midamble associated with the first frame format into a frame.

17. The second apparatus of claim 16, wherein, a first number of symbols comprised in the frame with the first frame format is different from a second number of symbols comprised in the frame with a second frame format which is generated based on a second midamble associated with the second frame format, or a first duration the frame with the first frame format is different from a second duration of the frame with the second frame format which is generated based on the second midamble associated.

18. The second apparatus of claims 16 or 17, wherein, a first number of symbols comprised in the frame with the first frame format is a multiple of a predefined minimum number of symbols comprised in a frame, or a first duration of the frame with the first frame format is a multiple of a pre-defined minimum duration of a frame.

19. The second apparatus of any of claims 11 to 18, wherein the second apparatus is further caused to: generate a second message indicating the first frame format; and transmit the second message to a third apparatus serving the first and second apparatuses.

20. The second apparatus of any of claims 11 to 19, wherein the first message is transmitted via a physical device to reader channel (PDRCH) and the frame is a device to reader (D2R) frame.

21. The second apparatus of any of claims 11 to 20, wherein, the first apparatus is an ambient internet of things (A-loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

22. A third apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, from a second apparatus, a second message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from a first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble.

23. The third apparatus of claim 22, wherein the first apparatus is an ambient internet of things (A- loT) device, the second apparatus is an loT reader, and the third apparatus is a network device or a terminal device.

24. A method comprising: transmitting, to a second apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and transmitting, based on the first message, the frame with the first frame format to the second apparatus.

25. A method comprising: receiving, from a first apparatus, a first message indicating a first frame format of a plurality of frame formats, wherein the first frame format is to be applied to a frame to be transmitted from the first apparatus to the second apparatus, wherein the plurality of frame formats comprise the first frame format and a second frame format different from the first frame format in terms of at least one of the following: a number of symbols comprised in a midamble, a symbol sequence of a midamble, or a modulation scheme of a midamble; and receiving, based on the first message, the frame with the first frame format from the first apparatus.