CN117441396A

CN117441396A - Reliable transmission over licensed and unlicensed frequency bands

Info

Publication number: CN117441396A
Application number: CN202180099059.9A
Authority: CN
Inventors: R·巴尔博萨·阿伯; C·罗萨; 吴春丽; 陶涛
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2021-04-06
Filing date: 2021-04-06
Publication date: 2024-01-23
Also published as: WO2022213238A1

Abstract

Example embodiments of the present disclosure relate to apparatuses, methods, devices, and computer-readable storage media for reliable transmission. The method comprises the following steps: in accordance with a determination that a data transmission is to be sent to the second device, performing a transmission attempt for the data transmission on the first set of resources; transmitting a signal to the second device on a second set of resources, the signal indicating a transmission attempt performed by the first device, the second set of resources being different from the first set of resources; and sending a data transmission to the second device on a third set of resources different from the first set of resources based on the failure of the transmission attempt. Thus, unlicensed spectrum may be used to transmit URLLC data, while latency and reliability requirements are met by using licensed spectrum as a backup resource for URLLC data.

Description

Reliable transmission over licensed and unlicensed frequency bands

Technical Field

Embodiments of the present disclosure relate generally to the field of telecommunications and, in particular, relate to devices, methods, apparatuses, and computer-readable storage media for reliable transmission on both licensed and unlicensed frequency bands.

Background

The 5G New Radio (NR) system architecture is interested in supporting ultra-reliable low-latency communications (URLLC) and industrial internet of things (IIoT) over both licensed and unlicensed spectrum. In general, unlicensed spectrum is shared between various terminal devices and radio access technologies, and thus it may be difficult to efficiently coordinate their access to channels. To avoid collisions of access channels, the terminal device may perform Clear Channel Assessment (CCA) based on energy detection on the unlicensed spectrum.

URLLC has very stringent requirements in terms of reliability and delay, e.g., a 99.999% probability of success within a delay as low as 1 ms. As one of the use cases in IIoT, time Sensitive Communications (TSC) are characterized by deterministic and periodic traffic, which also has stringent requirements on time-to-live. The lifetime is defined as the time that an application using a communication service can last without an expected message. For TSC, if two or more consecutive messages are not delivered within the delay budget, i.e. the lifetime equals 2 cycles, the communication service may be regarded as unavailable. Thus, supporting mission critical services (such as URLLC/TSC) on unlicensed spectrum is challenging, because unexpected interference on the channel may prevent high priority transmissions from occurring due to failure of the CCA procedure.

Disclosure of Invention

In general, example embodiments of the present disclosure provide a solution for reliable transmission on both licensed and unlicensed bands.

In a first aspect, a first device is provided. The first device includes at least one processor; at least one memory including computer program code; the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device at least to: in accordance with a determination that a data transmission is to be sent to the second device, performing a transmission attempt for the data transmission on the first set of resources; transmitting a signal to the second device on a second set of resources, the signal indicating a transmission attempt performed by the first device, the second set of resources being different from the first set of resources; and sending a data transmission to the second device on a third set of resources different from the first set of resources based on the failure of the transmission attempt.

In a second aspect, a second device is provided. The second device includes at least one processor; at least one memory including computer program code; the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to at least: receiving a signal from the first device on the second set of resources, the signal indicating a transmission attempt performed by the first device, the transmission attempt being performed for a data transmission to be sent on the first set of resources; determining, based on the receipt of the signal, whether a data transmission is sent on the first set of resources; and in accordance with a determination that no data transmission is received on the first set of resources, receiving a data transmission from the first device on a third set of resources different from the first set of resources.

In a third aspect, a method is provided. The method comprises the following steps: in accordance with a determination that a data transmission is to be sent to a second device, performing, at a first device, a transmission attempt for the data transmission on a first set of resources; transmitting a signal to the second device on a second set of resources, the signal indicating a transmission attempt performed by the first device, the second set of resources being different from the first set of resources; and sending a data transmission to the second device on a third set of resources different from the first set of resources based on the failure of the transmission attempt.

In a fourth aspect, a method is provided. The method comprises the following steps: receiving, at the second device, a signal from the first device on the second set of resources, the signal indicating a transmission attempt performed by the first device, the transmission attempt being performed for a data transmission to be sent on the first set of resources; determining, based on the receipt of the signal, whether a data transmission is sent on the first set of resources; and in accordance with a determination that no data transmission is received on the first set of resources, receiving a data transmission from the first device on a third set of resources different from the first set of resources.

In a fifth aspect, there is provided a first apparatus comprising: means for performing, at the first device, a transmission attempt for the data transmission on the first set of resources in accordance with a determination that the data transmission is to be sent to the second device; means for transmitting a signal to the second apparatus on a second set of resources, the signal indicating a transmission attempt performed by the first apparatus, the second set of resources being different from the first set of resources; and means for sending a data transmission to the second apparatus on a third set of resources different from the first set of resources based on the failure of the transmission attempt.

In a sixth aspect, there is provided a second apparatus comprising: means for receiving, at the second apparatus, a signal from the first apparatus on the second set of resources, the signal indicating a transmission attempt performed by the first apparatus, the transmission attempt being performed for a data transmission to be sent on the first set of resources; means for determining from receipt of the signal whether a data transmission is sent on the first set of resources; and in accordance with a determination that no data transmission is received on the first set of resources and a data transmission is received from the first apparatus on a third set of resources different from the first set of resources.

In a seventh aspect, there is provided a computer readable medium having stored thereon a computer program which, when executed by at least one processor of a device, causes the device to perform the method according to the third aspect.

In an eighth aspect, there is provided a computer readable medium having stored thereon a computer program which, when executed by at least one processor of a device, causes the device to perform the method according to the fourth aspect.

Other features and advantages of embodiments of the present disclosure will be apparent from the following description of the particular embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the embodiments of the disclosure.

Drawings

Embodiments of the present disclosure are set forth in an illustrative sense, the advantages of which are explained in more detail below with reference to the drawings, in which:

FIG. 1 illustrates an example environment in which example embodiments of the present disclosure may be implemented;

fig. 2 shows a signaling diagram illustrating a reliable transport mechanism according to some example embodiments of the present disclosure;

fig. 3 illustrates a schematic diagram of a reliable transport mechanism according to some example embodiments of the present disclosure;

fig. 4 illustrates a schematic diagram of a reliable transport mechanism according to some example embodiments of the present disclosure;

fig. 5 illustrates a flowchart of an example method of reliable transmission according to some example embodiments of the present disclosure;

fig. 6 illustrates a flowchart of an example method of reliable transmission according to some example embodiments of the present disclosure;

FIG. 7 illustrates a simplified block diagram of a device suitable for implementing exemplary embodiments of the present disclosure; and

fig. 8 illustrates a block diagram of an example computer-readable medium, according to some embodiments of the disclosure.

The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements.

Detailed Description

Principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described merely for the purpose of illustrating and helping those skilled in the art understand and practice the present disclosure and are not meant to limit the scope of the present disclosure in any way. The disclosure described herein may be implemented in various other ways besides those described below.

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 skill in the art to which this disclosure belongs.

In this disclosure, references to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It will be understood that, although the terms "first" and "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish between functions of the various elements. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

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," "includes," "including," "has," "including," "includes" and/or "including …" when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof.

As used in this application, the term "circuitry" may refer to one or more or all of the following:

(a) Pure hardware circuit implementations (such as implementations using only analog and/or digital circuitry), and

(b) A combination of hardware circuitry and software, such as (as applicable):

(i) Combination of analog and/or digital hardware circuit(s) and software/firmware, and

(ii) Any portion of the hardware processor(s) with software, including the digital signal processor(s), software, and memory(s), working together to cause a device, such as a mobile phone or server, to perform various functions, and

(c) Hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), that require software (e.g., firmware)

The operation is performed, but software may not exist when the operation is not required.

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

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as a fifth generation (5G) system, long Term Evolution (LTE), LTE-advanced (LTE-a), wideband Code Division Multiple Access (WCDMA), high Speed Packet Access (HSPA), narrowband internet of things (NB-IoT), and so forth. Furthermore, the communication between the terminal device and the network device in the communication network may be performed according to any suitable generation communication protocol, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) New Radio (NR) communication protocols, and/or any other protocol currently known or to be developed in the future. Embodiments of the present disclosure may be applied to various communication systems. In view of the rapid development of communications, there are, of course, future types of communication techniques and systems that can embody the present disclosure. The scope of the present disclosure should not be limited to only the above-described systems.

As used herein, the term "network device" refers to a node in a communication network via which a terminal device is able to access the network and receive services therefrom. A network device may refer to a Base Station (BS) or an Access Point (AP), e.g., a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR next generation NodeB (gNB), a Remote Radio Unit (RRU), a Radio Header (RH), a Remote Radio Head (RRH), a relay, a low power node (such as femto, pico), etc., depending on the terminology and technology applied. The network device is allowed to be defined as part of the gNB, e.g. in CU/DU splitting, in which case the network device is defined as gNB-CU or gNB-DU.

The term "terminal device" refers to any terminal device capable of wireless communication. By way of example, and not limitation, a terminal device may also be referred to as a communication device, user Equipment (UE), subscriber Station (SS), portable subscriber station, mobile Station (MS), or Access Terminal (AT). The terminal devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal Digital Assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, notebook computer embedded devices (LEEs), notebook computer mounted devices (LMEs), USB dongles, smart devices, wireless Customer Premises Equipment (CPE), internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automation processing chain context), consumer electronic devices, devices operating on a commercial and/or industrial wireless network, and the like. The terminal device may also correspond to a Mobile Terminal (MT) part of an Integrated Access and Backhaul (IAB) node (also referred to as a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user device" and "UE" may be used interchangeably.

Although in various example embodiments, the functions described herein may be performed in fixed and/or wireless network nodes, in other example embodiments, the functions may be implemented in a user equipment device (such as a cell phone or tablet or laptop or desktop or mobile IoT device or fixed IoT device). For example, the user equipment device may be suitably equipped with corresponding capabilities as described in connection with the fixed and/or wireless network node(s). The user equipment device may be a user equipment and/or a control device (such as a chipset or processor) configured to control the user equipment when installed in the user equipment. Examples of such functions include a bootstrapping server function and/or a home subscriber server, which may be implemented in a user equipment device by providing the user equipment device with software configured to cause the user equipment device to perform from the perspective of these functions/nodes.

Current high reliability low latency communications (such as IIOT and URLLC) are suitable for implementation in controlled environments where failure of LBT is not expected to occur, or only infrequently. However, unlicensed spectrum is shared between various devices and Radio Access Technologies (RATs), and thus there may be interference from other RATs present in an uncontrolled environment. When high reliability low delay communications are implemented over unlicensed spectrum, there are two problems to be solved, 1) it is difficult to efficiently coordinate access from multiple terminal devices to an operating channel by simply utilizing a conventional CCA procedure; and 2) sporadic interference can severely impact the ability of a communication system, such as an NR unauthorized (NR-U) system, in terms of low latency and high reliability. In particular, in the event of LBT failure, it may prevent the terminal device from transmitting data on the operating channel for tens of milliseconds (and in some cases even hundreds of milliseconds).

Taking the example of URLLC, URLLC is characterized by sporadic traffic that needs to be successfully transmitted with very short delay when arriving at the terminal device. For Uplink (UL) transmissions, grant (CG) resources (i.e., periodic resources pre-allocated for UL transmissions) are configured to avoid easily delayed scheduling procedures. However, on unlicensed bands and in the case of sporadic URLLC traffic, once LBT fails, the terminal device will not be able to transmit in CG resources and the network device (e.g., the gNB) is unaware that the terminal device has high priority data to transmit. For dynamically scheduled transmissions, and for periodic deterministic transmissions of TSCs, the network device may expect the terminal device to transmit on a set of authorized resources scheduled or preconfigured by the network device. If LBT fails, the terminal device cannot send data until new grants are available, which in addition to detrimental jitter, especially for TSCs, results in a potentially high hybrid automatic repeat request (HARQ) delay.

In order to address the drawbacks of unlicensed bands, several solutions have been proposed and tried. For example, a Packet Data Convergence Protocol (PDCP) duplication scheme has relatively low implementation complexity, however, it has very high cost in terms of spectrum efficiency because the load in the network is effectively doubled when duplication is implemented.

By scheduling transmissions simultaneously on multiple carriers or sub-bands, the probability of data being successfully transmitted may be increased. However, such a scheme has high implementation complexity on the terminal side. Since the terminal device does not know which transmission will succeed on LBT, it must prepare multiple Transport Blocks (TBs) at the same time. Furthermore, the MAC layer currently does not support replicating the same TB over multiple grants.

Another proposed solution is autonomous retransmission based on CG retransmission timers. This scheme has a high delay because the terminal device must wait for the CG retransmission timer to expire until the next attempt to transmit data. Therefore, CG retransmission is still prone to LBT failure on unlicensed bands.

To address the above and other potential problems, embodiments of the present disclosure provide a reliable transmission scheme for dynamic scheduling or both deterministic and CG transmissions. Typically, in this scheme, the terminal device informs the network device of data transmission attempts or LBT failures on the original frequency band (e.g., unlicensed frequency band) in a flexible and timely manner. Upon failure of LBT on the unlicensed band, the terminal device may send a data transmission using the backup resources allocated from the other band. Furthermore, in the event that the data transmission was successfully sent on the original frequency band, the network device may reallocate the backup resources for other transmissions. In this way, transmissions requiring low latency and high reliability can be sent on both licensed and unlicensed bands, and spectral efficiency is improved.

FIG. 1 illustrates an example environment 100 in which example embodiments of the present disclosure may be implemented. As shown in fig. 1, the network system 100 includes a first device 110, a second device 120, and a third device 130.

The first device 110 (hereinafter also referred to as terminal device 110 or UE 110) is located within radio coverage of the second device 120 and may communicate with the second device 120. The third device 130 is also located within the radio coverage area and may communicate with the second device 120. The link from the first device 110 or the third device 130 to the second device 120 is referred to as an Uplink (UL), and the link from the second device 120 to the first device 110 or the third device 130 is referred to as a Downlink (DL).

The first device 110 and the third device 130 (hereinafter collectively referred to as terminal devices) may transmit data on a plurality of carriers or sub-bands (including licensed bands and unlicensed bands, also referred to as channels). The data transmissions of the first device 110 and the third device 130 may be transmitted in an uplink configuration grant manner, a dynamic scheduling manner, or a deterministic manner, which will be discussed in detail below.

Sometimes, the first device 110 and the third device 130 may transmit data on the same channel at the same time and thereby interfere with each other. To avoid interference and collision of access channels, a terminal device may perform a transmission attempt, such as CCA (e.g., LBT), prior to data transmission. During the CCA procedure, the terminal device performs energy detection on the channel to determine whether the channel is busy. If the result of the CCA indicates that the channel is busy, in other words, LBT fails, data cannot be transmitted on the channel.

The second device 120 may be a network device, e.g. a base station providing radio coverage for a terminal device. The second device 120 may send various transmission configurations to the first device 110 and the third device 130, respectively, via a plurality of messages. For example, in the case where the data transmission of the first device 110 is an uplink configuration grant transmission, the second device 120 may transmit a transmission configuration indicating resource allocation, priority of data transmission, or the like via an RRC message. In the case where the data transmission of the first device 110 is a dynamically scheduled transmission or a deterministic configured transmission, the second device 120 may send a transmission configuration indicating resource allocation, priority of data transmission, etc., via Downlink Control Information (DCI).

The resource allocation may include a first set of resources, e.g., a first Transmission Time Interval (TTI), corresponding to the original transmission occasion. The first set of resources may be allocated by the second device 120 from an unlicensed frequency band. In some example embodiments, the second device 120 may also transmit a transmission configuration indicating a third set of resources for data transmission. The third set of resources may be allocated by the second device 120 from an unlicensed frequency band or a licensed frequency band. The third set of resources is different from the first set of resources and corresponds to a backup transmission occasion that is later than the original occasion, e.g., the second TTI. In case the first set of resources and the third set of resources are allocated from two unlicensed bands, respectively, the unlicensed band of the third set of resources may be more reliable than the unlicensed band of the first set of resources, e.g. in a less congested channel.

According to the transmission configuration, if the terminal device determines that the data transmission is to be transmitted, it may perform a transmission attempt on the first set of resources. If the transmission attempt is successful, the terminal device may send a data transmission at the original transmission occasion. Otherwise, if transmission data is not allowed to be transmitted due to a transmission attempt failure, the first device 110 may transmit data transmission at a backup transmission occasion by using the third set of resources.

The transmission configuration indicating the third set of resources may be transmitted together with the transmission configuration indicating the first set of resources or separately. In the latter case, the third set of resources may be pre-allocated by the second device 120 and at least the transmission configuration indicating the third set of resources may be sent prior to the transmission attempt. Alternatively, the third set of resources may be allocated by the second device 120 upon determining that the transmission attempt failed.

In some example embodiments, the second device 120 may also allocate a second set of resources for signals indicative of transmission attempts performed by the first device 110. The second set of resources may be allocated from unlicensed spectrum or licensed spectrum and different from the first set of resources. A signal may be transmitted by the terminal device to indicate an intent to send a data transmission on the first set of resources at an original transmission occasion.

Alternatively, a further signal may be used to indicate the failure of the transmission attempt. In this case, upon receiving the signal, the second device 120 may determine that there is no data transmission to be sent on the first set of resources, as will be discussed in detail below.

The second device 120 may send a configuration of a signal indicating at least the second set of resources in an RRC message (e.g., a configurable grantconfigug Information Element (IE), logicalChannelConfig IE, etc.).

The signal includes, but is not limited to, a reference signal, a preamble signal, a Scheduling Request (SR) signal, or Uplink Control Information (UCI). UCI may be transmitted on a Physical Uplink Control Channel (PUCCH) configured on a licensed band, for example, by the second device 120. As one of implementation, the signal may be configured like an SR signal to have a period that matches the period of CG resources (i.e., the first set of resources) associated in the unlicensed band.

In case the data transmission is a CG transmission, the signal may also indicate that the HARQ process for the third set of resources is associated with the HARQ process for the first set of resources, as will be discussed in detail below.

In some cases, the signal for the transmission attempt may be optional. For example, where the data transmission is a dynamically scheduled transmission or a deterministic transmission, and the first set of resources is allocated from an unlicensed spectrum, the second device 120 knows, without any signal from the first device 110, that the data transmission will occur at the original transmission occasion. In this case, if the second device 120 does not receive a data transmission on the first set of resources as expected, a third set of resources for the backup resource will be used.

It should be understood that the number of terminal devices and network devices shown in fig. 1 is given for illustrative purposes and is not meant to be limiting. Network system 100 may include any suitable number of terminal devices, network devices, and additional devices suitable for implementing implementations of the present disclosure. Although the first device 110 and the third device 130 are shown as mobile phones and the second device 120 is shown as a base station, they may be other devices than mobile phones, base stations, or parts thereof.

Depending on the communication technology, network architecture 200 may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency Division Multiple Access (OFDMA) network, a single carrier frequency division multiple access (SC-FDMA) network, or any other network. The communications discussed in network 100 may conform to any suitable standard including, but not limited to, new radio access (NR), long Term Evolution (LTE), LTE evolution, LTE-advanced (LTE-a), wideband Code Division Multiple Access (WCDMA), code Division Multiple Access (CDMA), CDMA2000, global system for mobile communications (GSM), and the like. Furthermore, the communication may be performed according to any generation communication protocol currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols. The techniques described herein may be used for the wireless networks and radio technologies described above as well as other wireless networks and radio technologies. For clarity, certain aspects of these techniques are described below for LTE, and LTE terminology is used in much of the description below.

The principles and implementations of the present disclosure will be described in detail below with reference to fig. 2 through 6. Fig. 2 shows a signaling diagram illustrating a reliable transport mechanism according to some example embodiments of the present disclosure. For discussion purposes, the process 200 will be described with reference to fig. 1. Process 200 may involve first device 110 and second device 120.

As shown in fig. 2, the second device 120 sends 205 a transmission configuration for data transmission to the first device 110. In some example embodiments, the transmission configuration may be sent in an RRC message configured to configure a first set of resources corresponding to an original transmission occasion, e.g., a first TTI. Alternatively, the transmission configuration may be sent in DCI for indicating the first set of resources. In some example embodiments, the first set of resources may be allocated from an unlicensed frequency band.

In some example embodiments, the second device 120 may also send a transmission configuration for the third set of resources to the first device 110. The third set of resources may correspond to a backup transmission occasion that is later than the original transmission occasion, e.g., a second TTI. The third set of resources may be different from the first set of resources and may be allocated from an unlicensed frequency band or a licensed frequency band. In the case where the first set of resources and the third set of resources are allocated from two unlicensed bands, respectively, the unlicensed band for the third set of resources may be more reliable than the unlicensed band for the first set of resources, e.g., in a less congested channel, to ensure that when a data transmission fails to be sent on the first set of resources, it may be successfully sent on the third set of resources.

In the case where the data transmission is a UL CG transmission, the first set of resources may be indicated in a UL grant for the data transmission from the second device 120, and the third set of resources is pre-allocated by the second device 120. In the case that the data transmission is a dynamically scheduled transmission or a deterministic transmission, the second device 120 may send to the first device 110 at least a first DCI indicating a third set of resources. In some embodiments, the first DCI may further indicate the first set of resources. In some other embodiments, the second device 120 may send additional DCI, e.g., a second DCI, to the first device 110 indicating the third set of resources.

After receiving the transmission configuration, the first device 110 determines 210 that the data transmission is to be sent to the second device 120. The second device 120 knows the data transmission to be sent at the original transmission occasion. In some cases, the second device 120 may know that the data transmission is to be sent or is not to be sent based on the signal sent from the first device 110.

The first device 110 performs 215 a transmission attempt for a data transmission on the first set of resources. The transmission attempt may include a CCA procedure. In these cases, the first device 110 may transmit 220 a signal indicating the transmission attempt performed by the first device 110. In these cases, the second device 120 may also allocate a second set of resources for the signal from the unlicensed spectrum or licensed spectrum for transmission attempts for data transmission. The second set of resources may be different from the first set of resources.

The signal may be sent prior to or substantially simultaneously with the transmission attempt. In these embodiments, the second device 120 may transmit a first configuration of signals indicating at least a second set of resources, which may correspond to a first transmission opportunity preceding the original transmission opportunity.

In some example embodiments, the signal may be associated with a plurality of data transmissions on consecutive resources including the first set of resources. In these embodiments, the second device 120 may determine, upon receipt of the signal, whether a first one of the consecutive resources is detected.

Additionally or alternatively, a further signal may be used by the terminal device to indicate that no data transmission is to be sent on the first set of resources at the original transmission occasion due to a transmission attempt failure. In other words, the further signal may be sent only when a transmission attempt failure occurs. To this end, the terminal device may send a further signal after the transmission attempt. In these embodiments, the second device 120 may transmit a second configuration of the further signal, the second configuration indicating at least resources for the further signal, the resources may correspond to a second transmission occasion after the transmission attempt is performed.

In some example embodiments, the signal for the transmission attempt may be a simple flag or a 1-bit indicator to inform only the transmission attempt on the first set of resources. The signal may also indicate HARQ related information. In some other example embodiments, the signal may be a multi-bit indicator sent in the PUCCH UCI, which is also used to indicate information about the data transmission, such as HARQ process number (e.g., HARQ ID) or other HARQ related information. In this way, switching from the first set of resources to the third set of resources does not result in HARQ round trip delay.

In some example embodiments, the signal may indicate a first HARQ Process Number (HPN) for data transmission on the first set of resources. In some other example embodiments, the signal may indicate a second HPN for data transfer on the third set of resources, and the second HPN is different from the first HPN.

In other example embodiments, multiple indicators that may be distinguished by time, frequency, space, or code domain may be associated with a data transmission. In these embodiments, the first device 110 may select a transmission indicator that indicates additional information about the data transmission. For example, if a transfer configuration is available for HPN 1 and HPN 2, the first device 110 may select a first indicator if a data transfer is attempted for HPN 1 and a second indicator if a data transfer is attempted for HPN 2.

In other cases, the signal is optional for data transmission. For example, where the data transmission is a dynamically scheduled transmission or a deterministic transmission, and the first set of resources is allocated from an unlicensed spectrum, the second device 120 knows the data transmission that will occur at the original transmission occasion without any signal or indicator from the first device 110. If the second device 120 does not receive a data transmission on the first set of resources as expected, a third set of resources for the backup resource is expected to be used.

Referring to fig. 3, fig. 3 illustrates a schematic diagram of a reliable transport mechanism according to some example embodiments of the present disclosure. As shown in fig. 3, a first set of resources 312 allocated from frequency band 310 corresponds to original transmission opportunity 302, and a third set of resources 324 and 322 allocated from frequency band 320 correspond to backup transmission opportunity 304 and first transmission opportunity 301, respectively.

Upon determining that the data transmission is to be sent at the original transmission opportunity 302, the first device 110 may send a signal comprising a transmission indicator on the second set of resources 322 at the first transmission opportunity 301. The first device 110 then performs CCA on the first set of resources. For example, the first device 110 may perform LBT on the channel to determine whether the first set of resources is available for data transmission.

If the result of the CCA indicates that the channel is busy, the first device 110 determines 225 that the first set of resources 312 is not available for data transmission. Since the second device 120 expects data transmission at the original transmission opportunity based on the signal received at the first transmission opportunity 301, however no data transmission is received on the first set of resources 312, the second device 120 can determine that the data transmission will be sent on the third set of resources 324 at the backup transmission opportunity 304. In this case, the second device 120 may schedule retransmission of the HARQ process identified in the signal on the third set of resources 324.

The first device 110 sends 230 a data transmission to the second device on the third set of resources 324 at the backup transmission opportunity 304. As described above, the third set of resources 324 may be pre-allocated by the second device 120. In embodiments where the third set of resources 324 is not pre-allocated by the second device 120, the first device 110 may begin monitoring the PDCCH on a particular time/frequency resource to clarify the allocation of the third set of resources 324 when transmitting a signal.

Fig. 4 illustrates a schematic diagram of a reliable transport mechanism according to some example embodiments of the present disclosure. The first set of resources 412 allocated from the frequency band 410 corresponds to the original transmission occasion 402 and the third set of resources 424 and 422 allocated from the frequency band 420 correspond to the backup transmission occasion 304 and the first transmission occasion 401, respectively.

As shown in fig. 4, if the result of the CCA indicates that the channel is clear, the first device 110 determines that the first set of resources 412 is available for data transmission. The first device 110 may then send a data transmission on the first set of resources 412 at the original transmission opportunity 402. Since the second device 120 receives the data transmission on the first set of resources 412 as expected, the second device 120 may reallocate 235 the third set of resources 424 for additional transmission.

As shown in fig. 3 and 4, in the time domain, there are time offsets 303 and 403 between the first set of resources 312, 412 and the third set of resources 324, 424. It may be beneficial to provide such a time offset between the first set of resources and the third set of resources. In some example embodiments, the time offset may be associated with the ability of the first device 110 to switch data transmission from the first set of resources to the third set of resources, a reaction time of the second device 120 to allocate the third set of resources to the first device, a packet delay budget, and so forth.

According to embodiments of the present disclosure, a solution is provided for reliable transmission on both licensed and unlicensed bands, which facilitates low-latency high-reliability communications. In such a reliable transmission scheme, the terminal device can inform the network device of an attempt or LBT failure of data transmission on the original frequency band (e.g., unlicensed frequency band) in a flexible and timely manner. Upon failure of LBT on an unlicensed band, the terminal device may send a data transmission using backup resources allocated from less congested bands. Furthermore, if the data transmission is successfully sent on the original frequency band, the network device may reallocate the backup resources for additional transmissions. In this way, communication services requiring low latency and high reliability can be delivered on both licensed and unlicensed bands, and spectral efficiency can be significantly improved.

Fig. 5 illustrates a flowchart of an example method 500 of reliable transmission according to some example embodiments of the present disclosure. The method 500 may be implemented at a terminal device (e.g., the first device 110 described with reference to fig. 1).

At 510, the first device 110 determines whether a data transmission is to be sent to the second device 120. The data transmission may be a UL CG transmission, a dynamically scheduled transmission, or a deterministic transmission. In some example embodiments, the data transmission may be one of a plurality of consecutive transmissions.

If the data transmission is determined to be sent, at 520, the first device 110 performs a transmission attempt for the data transmission on the first set of resources. For example, the first device 110 performs CCA on a first set of resources, which may correspond to an original transmission opportunity. For example, the first device 110 may perform LBT based on energy detection on a channel between the first device 110 and the second device 120. In the case where the data transmission is a UL CG transmission, the first set of resources may be configured in a UL grant for the data transmission from the second device 120.

The second device knows the data transmission to be sent on the first set of resources at the original transmission occasion. After determining that the data transmission is to be sent, the first device 110 sends a signal to the second device 120 on the second set of resources at 530. The signal may indicate a transmission attempt performed by the first device 110. In some example embodiments, the signal may include, but is not limited to, a reference signal, a preamble signal, an SR signal, or UCI.

The second set of resources may be preconfigured by the second device 120. In some example embodiments, the first device 110 may also receive a first configuration of signals from the second device 120. The first configuration may indicate at least a second set of resources for the signal. The second set of resources may correspond to a first transmission occasion that is different from an original transmission occasion for the first set of resources. The second set of resources may be allocated from unlicensed spectrum or licensed spectrum.

In some example embodiments, the first configuration may indicate that the signal is associated with a first channel having a predetermined priority. In some example embodiments, the signal is associated with a plurality of data transmissions on consecutive resources comprising the first set of resources.

In embodiments where the data transmission is a dynamically scheduled transmission or a deterministic transmission, the second device 120 knows the data transmission that will occur at the original transmission opportunity without any explicit signal or indicator from the first device 110.

At 540, the first device 110 determines whether the transmission attempt failed. Failure of the transmission attempt may indicate that the channel is busy or that the first set of resources is not available for data transmission.

If the first device 110 determines that the transmission attempt failed, the first device 110 sends a data transmission to the second device 120 on the third set of resources at 550. In this case, the first device 110 may switch the data transmission from the first set of resources to a third set of resources allocated by the second device 120 as backup resources for the data transmission. The third set of resources may correspond to a backup transmission occasion that is later than the original occasion.

In embodiments where the data transmission is a UL CG transmission, the first device 110 may receive a first RRC message from the second device 120 to configure the third set of resources. In some example embodiments, the first RRC message may also configure the first set of resources.

Alternatively, the first set of resources and the third set of resources may be configured in separate RRC messages. In this case, the first RRC message is different from the second RRC message received from the second device 120 to configure the first set of resources.

In the case where the data transmission is a dynamically scheduled transmission or a deterministic transmission, after determining 540 that the transmission attempt failed, the first device 110 may begin monitoring the PDCCH on the particular time/frequency resource for allocation of a third set of resources for the data transmission. In this case, the first device 110 may also receive a transmission configuration indicating at least a third set of resources for data transmission.

The transmission configuration for the third set of resources may be transmitted together with the transmission configuration for the first set of resources or separately therefrom. In some example embodiments, both the first resource and the third resource set are indicated in the first DCI from the second device 120. In some other example embodiments, the third set of resources may be indicated in a first DCI, and the first set of resources may be located in a second DCI different from the first DCI.

In some example embodiments, the second set of resources and the third set of resources may be allocated from the same frequency band (e.g., licensed frequency band).

In some example embodiments, after determining that the transmission attempt failed, the first device 110 may send a further signal to the second device 120 indicating that the transmission attempt failed. In these embodiments, the first device 110 may also receive a second configuration of the further signal from the second device 120.

The second configuration may indicate at least a resource for the further signal, which resource may correspond to a second transmission occasion preceding the original transmission occasion. As with the third set of resources, resources for additional signals may be allocated from unlicensed spectrum or licensed spectrum. The additional signals may include, but are not limited to, a reference signal, a preamble signal, an SR signal, or UCI.

In some example embodiments, the signal may further indicate a first HARQ process number for data transmission on the first set of resources. Alternatively, the signal may also indicate a second HARQ process number for data transmission on the second set of resources, and the second HARQ process number is different from the first HARQ process number.

In embodiments supporting multiple candidate indicators associated with data transmission by differentiating in the time, frequency, spatial, or code domain. In these embodiments, the first device 110 may select an indicator from a plurality of candidate indicators that indicates additional information about the data transmission. For example, if a transfer configuration is available for HPN 1 and HPN 2, the first device 110 may select a first indicator if a data transfer is attempted for HPN 1 and a second indicator if a data transfer is attempted for HPN 2.

If the first device 110 determines that the transmission attempt was successful, the first device 110 may determine that the first set of resources is available for data transmission. In this case, the first device 110 may send a data transmission on the first set of resources 412 at the original transmission opportunity. Since the second device 120 receives data transmissions on the first set of resources as expected, the second device 120 may reallocate the third set of resources for additional transmissions.

In some example embodiments, in the time domain, there is a time offset between the first set of resources and the second set of resources. It may be beneficial to provide such a time offset between the first set of resources and the second set of resources. In some example embodiments, the time offset may be associated with the ability of the first device 110 to switch data transmission from the first set of resources to the second set of resources, a reaction time of the second device 120 to allocate the second set of resources to the first device, a packet delay budget, and so forth.

According to an embodiment of the present disclosure, a reliable transport mechanism is provided. By providing backup resources in less congested frequency bands (e.g., licensed bands), delay and reliability requirements for data transmission can be met even if LBT fails on the original frequency band.

Fig. 6 illustrates a flowchart of an example method 600 of reliable transmission according to some example embodiments of the present disclosure. The method 600 may be implemented at a network device (e.g., the second device 120 described with reference to fig. 1).

At 610, the second device 120 receives a signal from the first device 110 on the second set of resources. The signal may indicate a transmission attempt performed by the first device 110 and the transmission attempt is performed for a data transmission to be sent on the first set of resources. With this signal, the second device 120 knows that a data transmission is to be sent.

In some example embodiments, the second device 120 may allocate a first set of resources for data transmission. The first set of resources may correspond to an original transmission opportunity. The data transmission may be a UL CG transmission, a dynamically scheduled transmission, or a deterministic transmission. In some example embodiments, the data transmission may be one of a plurality of consecutive transmissions.

In embodiments where the data transmission is a UL CG transmission, the second device 120 may send a UL grant for the data transmission indicating the first set of resources. Alternatively, the second device 120 may configure the first set of resources in an RRC message.

In embodiments where the data transmission is a dynamically scheduled transmission or a deterministic transmission, the second device 120 may send downlink control information to the first device 110 indicating the first set of resources.

In some example embodiments, the second device 120 may send a first configuration of signals to the first device 110. The first configuration may indicate at least a second set of resources for the signal, and the second set of resources is allocated from unlicensed spectrum or licensed spectrum. The signal may include, but is not limited to, a reference signal, a preamble signal, an SR signal, or UCI. UCI may be transmitted on a Physical Uplink Control Channel (PUCCH) configured on the licensed band, e.g., by the second device 120.

In some example embodiments, the signal may not be present. For example, where the data transmission is a dynamically scheduled transmission or a deterministic transmission, the second device 120 knows the data transmission that will occur at the original transmission opportunity without any signal or indicator from the first device 110.

At 620, the second device 120 determines whether a data transmission is sent on the first set of resources. The second device 120 may perform reference signal detection on the first set of resources. In some example embodiments, the second device 120 may perform demodulation reference signal (DMRS) detection on the first set of resources to determine whether a data transmission is sent on the first set of resources.

For another example, the second device 120 may receive a further signal from the first device 110 indicating a failure of the transmission attempt performed by the first device 110. In this case, the second device 120 may also transmit a second configuration indicating at least the resources for the further signal. The resources may be allocated from unlicensed spectrum or licensed spectrum. After receiving the further signal, the second device 120 may determine that no data transmission is sent on the first set of resources.

In embodiments where the signal is associated with multiple data transmissions on consecutive resources including the first set of resources, the second device 120 may determine, upon receipt of the signal, whether the first one of the consecutive resources is detected.

If the second device 120 determines that no data transmission was received on the first set of resources, then at 630 the second device 120 receives a data transmission from the first device 110 on the third set of resources. The third set of resources is different from the first set of resources. In some example embodiments, the third set of resources and the second set of resources may be allocated from the same frequency band.

In some example embodiments, the second device 120 may send a first RRC message to the first device 110 to configure the third set of resources. The first RRC may also configure the first set of resources.

In some other example embodiments, the second device 120 may send a second RRC message to the first device 110 to configure the first set of resources. In this case, the first RRC is different from the second RRC.

In embodiments where the data transmission is a dynamically scheduled transmission or a deterministic transmission, the second device 120 may send the first DCI to the first device 110. The first DCI may indicate a third set of resources. In these embodiments, the first set of resources may be indicated in the same DCI or in a different DCI. For example, the first DCI may also indicate a first set of resources. Alternatively, the second device 120 may also transmit a second DCI indicating the first set of resources.

In some example embodiments, the first set of resources may be allocated from an unlicensed spectrum, while the third set of resources may be allocated from another unlicensed spectrum or licensed spectrum.

In some example embodiments, there may be a time offset in the time domain between the first set of resources and the third set of resources. The time offset may be associated with, for example, the ability of the first device to switch data transmissions from the first set of resources to the second set of resources, or the reaction time of the second device to assign the third set of resources to the first device.

In some example embodiments, the second device 120 may determine that the signal indicates a first HPN for data transfer on the first set of resources. In this case, the second device 120 may schedule retransmission of the data transmission on the second set of resources.

In some example embodiments, the second device 120 may determine that the signal indicates a second HPN for data transfer on the second set of resources. In this case, the second device 120 may schedule a retransmission of the data transmission on the third set of resources and the second HPN is different from the first HPN for the data transmission on the first set of resources.

By allocating the original resources and the backup resources respectively in different frequency bands, and by the signals for transmission attempts, data transmission can be successfully sent at low signaling cost, and delay and reliability requirements of data transmission can be satisfied.

In some example embodiments, a first apparatus (e.g., first device 110) capable of performing method 500 may include means for performing the respective steps of method 500. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The first apparatus may be implemented as the first device 110 or included in the first device 110. In some embodiments, the component may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause operation of the first apparatus.

In some example embodiments, a first apparatus includes: means for performing, at the first device, a transmission attempt for the data transmission on the first set of resources in accordance with a determination that the data transmission is to be sent to the second device; means for transmitting a signal to the second apparatus on a second set of resources, the signal indicating a transmission attempt performed by the first apparatus, the second set of resources being different from the first set of resources; and means for sending a data transmission to the second apparatus on a third set of resources different from the first set of resources in accordance with a failure of the transmission attempt.

In some example embodiments, the first apparatus further comprises: means for receiving a first radio resource control message from the second apparatus for configuring the third set of resources.

In some example embodiments, the first radio resource control message further configures a first set of resources.

In some example embodiments, the first radio resource control message is different from a second radio resource control message received from the second apparatus for configuring the first set of resources.

In some example embodiments, the first apparatus further comprises: means for receiving first downlink control information indicating a third set of resources from a second apparatus.

In some example embodiments, the first downlink control information further indicates a first set of resources.

In some example embodiments, the first downlink control information is different from second downlink control information received from the second apparatus indicating the first set of resources.

In some example embodiments, the first apparatus further comprises: the apparatus includes means for receiving a first configuration of signals from a second apparatus, the first configuration indicating at least a second set of resources for the signals, the second set of resources being allocated from unlicensed spectrum or licensed spectrum.

In some example embodiments, the first configuration indication signal is associated with a first channel having a predetermined priority.

In some example embodiments, the signal is associated with a plurality of data transmissions on consecutive resources comprising the first set of resources.

In some example embodiments, the signal comprises one of: a reference signal, a preamble signal, a scheduling request signal, or uplink control information.

In some example embodiments, the signal further comprises: a transmission indicator indicating at least one of: a first hybrid automatic repeat request, HARQ, process number for data transmission on the first set of resources, or a second HARQ process number for data transmission on the third set of resources, the second HARQ process number being different from the first HARQ process number.

In some example embodiments, the first apparatus further comprises: means for selecting a transmission indicator indicating a corresponding one of a first HARQ process number and a second HARQ process number for data transmission from a plurality of candidate indicators; and means for sending a signal comprising the transmission indicator to the second apparatus.

In some example embodiments, the first set of resources is allocated from an unlicensed spectrum and the third set of resources is allocated from one of another unlicensed spectrum or licensed spectrum.

In some example embodiments, there is a time offset in the time domain between the first set of resources and the third set of resources, and the time offset is associated with at least one of: the ability of the first device to switch data transmission from the first set of resources to the third set of resources, or the reaction time of the second device to allocate the third set of resources to the first device.

In some example embodiments, the first apparatus comprises a terminal device and the second apparatus comprises a network device.

In some example embodiments, a second apparatus (e.g., second device 120) capable of performing method 600 may include means for performing the respective steps of method 600. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The second apparatus may be implemented as the second device 120 or included in the second device 120. In some embodiments, the component may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause operation of the second apparatus.

In some example embodiments, the second apparatus includes: means for receiving, at the second apparatus, a signal from the first apparatus on the second set of resources, the signal indicating a transmission attempt performed by the first apparatus, the transmission attempt being performed for a data transmission to be sent on the first set of resources; means for determining from receipt of the signal whether a data transmission is sent on the first set of resources; and in accordance with a determination that no data transmission is received on the first set of resources and a data transmission is received from the first apparatus on a third set of resources different from the first set of resources.

In some example embodiments, the second apparatus further comprises: means for transmitting a first radio resource control message to the first apparatus for configuring the third set of resources.

In some example embodiments, the second apparatus further comprises: means for transmitting a second radio resource control message to the first apparatus for configuring the first set of resources, the second radio resource control message being different from the first radio resource control message.

In some example embodiments, the second apparatus further comprises: means for transmitting first downlink control information indicating the third set of resources to the first apparatus.

In some example embodiments, the second apparatus further comprises: means for transmitting second downlink control information indicating the first set of resources to the first apparatus, the second downlink control information being different from the first downlink control information.

In some example embodiments, the second apparatus further comprises: the apparatus includes means for transmitting, to a first apparatus, a first configuration of signals, the first configuration indicating at least a second set of resources for the signals, the second set of resources being allocated from unlicensed spectrum or licensed spectrum.

In some example embodiments, the signal further comprises a transmission indicator indicating at least one of: a first hybrid automatic repeat request, HARQ, process number for data transmission on the first set of resources, and a second HARQ process number for data transmission on the third set of resources, the second HARQ process number being different from the first HARQ process number.

In some example embodiments, the second apparatus further comprises: means for scheduling retransmission of data transmissions on the third set of resources based on a corresponding one of the first HARQ process number and the second HARQ process number.

In some example embodiments, the second apparatus further comprises: means for performing reference signal detection on the first set of resources.

Fig. 7 is a simplified block diagram of an apparatus 700 suitable for implementing embodiments of the present disclosure. Device 700 may be provided to implement a communication device, such as, for example, first device 110 or a second device as shown in fig. 1. As shown, device 700 includes one or more processors 710, one or more memories 720 coupled to processors 710, and one or more transmitters and receivers (TX/RX) 740 coupled to processors 710.

TX/RX 740 is used for two-way communication. TX/RX 740 has at least one antenna to facilitate communication. The communication interface may represent any interface necessary for communication with other network elements.

Processor 710 may be of any type suitable to the local technology network and may include, by way of non-limiting example, one or more of the following: general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), and processors based on a multi-core processor architecture. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock that is synchronized to the master processor.

Memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact Disks (CD), digital Video Disks (DVD), and other magnetic and/or optical storage devices. Examples of volatile memory include, but are not limited to, random Access Memory (RAM) 722 and other volatile memory that does not persist during power outages.

The computer program 730 includes computer-executable instructions that are executed by an associated processor 710. Program 730 may be stored in ROM 720. Processor 710 may perform any suitable actions and processes by loading program 730 into RAM 720.

Embodiments of the present disclosure may be implemented by the program 730 such that the device 700 may perform any of the processes of the present disclosure discussed with reference to fig. 2 and 5-6. Embodiments of the present disclosure may also be implemented in hardware or by a combination of software and hardware.

In some embodiments, program 730 may be tangibly embodied in a computer-readable medium that may be included in device 700 (such as in memory 720) or other storage device accessible to device 700. The device 700 may load the program 730 from a computer readable medium into the RAM 722 for execution. The computer readable medium may include any type of tangible, non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Fig. 8 shows an example of a computer readable medium 800 in the form of a CD or DVD. The computer readable medium has stored thereon the program 730.

In general, the various embodiments of the disclosure may be implemented using hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that blocks, apparatus, systems, techniques or methods 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.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product comprises computer executable instructions, such as instructions included in program modules, that are executed in a device on a target real or virtual processor to perform the method 500 and method 600 described above with reference to fig. 5-6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as desired. Machine-executable instructions of program modules may be executed within local or distributed devices. In a distributed device, program modules may be located in both local and remote memory storage media.

Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These 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, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the 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.

In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable an apparatus, device or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is 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 a 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.

Further, while operations are described in a particular order, this should not be construed 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 some cases, multitasking and parallel processing may be advantageous. Also, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the 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

1. A first device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device at least to:

in accordance with a determination that a data transmission is to be sent to a second device, performing a transmission attempt for the data transmission on a first set of resources;

transmitting a signal to the second device on a second set of resources, the signal indicating the transmission attempt performed by the first device, the second set of resources being different from the first set of resources; and

and sending the data transmission to the second device on a third set of resources different from the first set of resources based on the failure of the transmission attempt.

2. The first device of claim 1, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first device to:

A first radio resource control message is received from the second device for configuring the third set of resources.

3. The first device of claim 2, wherein the first radio resource control message further configures the first set of resources.

4. The first device of claim 2, wherein the first radio resource control message is different from a second radio resource control message received from the second device for configuring the first set of resources.

5. The first device of claim 1, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first device to:

first downlink control information indicating the third set of resources is received from the second device.

6. The first device of claim 5, wherein the first downlink control information further indicates the first set of resources.

7. The first device of claim 5, wherein the first downlink control information is different from second downlink control information received from the second device for indicating the first set of resources.

8. The first device of claim 1, wherein the first device is further caused to:

a first configuration of the signal is received from the second device, the first configuration indicating at least the second set of resources for the signal, the second set of resources being allocated from unlicensed spectrum or licensed spectrum.

9. The first apparatus of claim 8, wherein the first configuration indicates that the signal is associated with a first channel having a predetermined priority.

10. The first device of claim 1, wherein the signal is associated with a plurality of data transmissions on consecutive resources comprising the first set of resources.

11. The first device of claim 1, wherein the signal comprises one of: a reference signal, a preamble signal, a scheduling request signal, or uplink control information.

12. The first device of claim 1, wherein the signal further comprises: a transmission indicator indicating at least one of: a first hybrid automatic repeat request, HARQ, process number for the data transmission on the first set of resources or a second HARQ process number for the data transmission on the third set of resources, the second HARQ process number being different from the first HARQ process number.

13. A first device as claimed in claim 12, wherein the first device is caused to transmit the signal by:

selecting the transmission indicator from a plurality of candidate indicators, the transmission indicator indicating a corresponding one of the first HARQ process number and the second HARQ process number for the data transmission; and

the signal comprising the transmission indicator is sent to the second device.

14. The first device of claim 1, wherein the first set of resources is allocated from an unlicensed spectrum and the third set of resources is allocated from one of another unlicensed spectrum or a licensed spectrum.

15. The first device of claim 1, wherein there is a time offset between the first set of resources and the third set of resources in the time domain, and the time offset is associated with at least one of: the ability of the first device to switch the data transmission from the first set of resources to the third set of resources, or the reaction time of the second device to allocate the third set of resources to the first device.

16. The first device of claim 1, wherein the first device comprises a terminal device and the second device comprises a network device.

17. A second device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to at least:

receiving a signal from a first device on a second set of resources, the signal indicating a transmission attempt performed by the first device, the transmission attempt being performed for a data transmission to be transmitted on the first set of resources;

determining, based on the receiving of the signal, whether the data transmission is sent on the first set of resources; and

in accordance with a determination that no data transmission is received on the first set of resources, the data transmission is received from the first device on a third set of resources different from the first set of resources.

18. The second device of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

a first radio resource control message is sent to the first device for configuring the third set of resources.

19. The second device of claim 18, wherein the first radio resource control message further configures the first set of resources.

20. The second device of claim 18, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

a second radio resource control message is sent to the first device for configuring the first set of resources, the second radio resource control message being different from the first radio resource control message.

21. The second device of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

first downlink control information indicating the third set of resources is sent to the first device.

22. The second device of claim 21, wherein the first downlink control information further indicates the first set of resources.

23. The second device of claim 21, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

Transmitting, to the first device, second downlink control information indicating the first set of resources, the second downlink control information being different from the first downlink control information.

24. The second device of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

a first configuration of the signal is transmitted to the first device, the first configuration indicating at least the second set of resources for the signal, the second set of resources being allocated from unlicensed spectrum or licensed spectrum.

25. The second device of claim 17, wherein the signal is associated with a plurality of data transmissions on consecutive resources comprising the first set of resources.

26. The second device of claim 17, wherein the signal further comprises: a transmission indicator indicating at least one of: a first hybrid automatic repeat request, HARQ, process number for the data transmission on the first set of resources, and a second HARQ process number for the data transmission on the third set of resources, the second HARQ process number being different from the first HARQ process number.

27. The second device of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the second device to:

and scheduling retransmission of the data transmission on the third set of resources based on a corresponding one of the first HARQ process number and the second HARQ process number.

28. The second device of claim 17, wherein the signal comprises one of: a reference signal, a preamble signal, a scheduling request signal, or uplink control information.

29. The second device of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to determine whether the data transmission was received on the first set of resources by:

reference signal detection is performed on the first set of resources.

30. The second device of claim 17, wherein the first set of resources is allocated from an unlicensed spectrum and the third set of resources is allocated from one of another unlicensed spectrum or a licensed spectrum.

31. The second device of claim 17, wherein there is a time offset between the first set of resources and the third set of resources in the time domain, and the time offset is associated with at least one of: the ability of the first device to switch the data transmission from the first set of resources to the third set of resources, or the reaction time of the second device to allocate the third set of resources to the first device.

32. The second device of claim 17, wherein the first device comprises a terminal device and the second device comprises a network device.

33. A method, comprising:

in accordance with a determination that a data transmission is to be sent to a second device, performing, at a first device, a transmission attempt for the data transmission on a first set of resources;

34. A method, comprising:

at the second device, receiving a signal from the first device on the second set of resources, the signal indicating a transmission attempt performed by the first device, the transmission attempt being performed for a data transmission to be sent on the first set of resources;

35. A first apparatus, comprising:

means for performing, at the first device, a transmission attempt for the data transmission on the first set of resources in accordance with a determination that the data transmission is to be sent to the second device;

means for transmitting a signal to the second apparatus on a second set of resources, the signal indicating the transmission attempt performed by the first apparatus, the second set of resources being different from the first set of resources; and

means for sending the data transmission to the second apparatus on a third set of resources different from the first set of resources in accordance with a failure of the transmission attempt.

36. A second apparatus, comprising:

means for receiving, at a second apparatus, a signal from a first apparatus on a second set of resources, the signal indicating a transmission attempt performed by the first apparatus, the transmission attempt being performed for a data transmission to be sent on the first set of resources;

means for determining from the reception of the signal whether the data transmission is sent on the first set of resources; and

in accordance with a determination that no data transmission is received on the first set of resources, the data transmission is received from the first apparatus on a third set of resources different from the first set of resources.

37. A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 33.

38. A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 34.