Enhanced link budget procedure for initial access

Abstract

Embodiments of the present disclosure relate to an enhanced link budget procedure for initial access. According to embodiments of the present disclosure, a network device transmits a configuration of a random access channel, and a terminal device determines coverage enhancement and power boosting based on the configuration and a measured power. Therefore, collisions among terminal devices are reduced.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to communication technology, and more particularly, to methods, devices and computer readable media for enhanced link budget procedure for initial access. BACKGROUND

[0002] As the communication systems evolve, new technologies have been proposed. For example, technologies for improving coverage have been proposed. Terminal devices typically have limited power. Therefore, it is desirable to further improve the coverage of terminal devices. SUMMARY

[0003] Generally, embodiments of the present disclosure relate to a method for enhanced link budget procedure and a corresponding device.

[0004] In a first aspect, a first device is provided. The first device comprises at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the first device to receive, at the first device, a configuration of a random access channel from a second device. The configuration indicates at least resources allocated to a plurality of coverage enhancement levels. The first device is further caused to determine, from the plurality of coverage enhancement levels, a target coverage enhancement level based on a measured power of a first signal received from the second device. The first device is further caused to determine a transmission power level based on the measured power. The first device is further caused to select, based on the configuration and the transmission power level, a subset of resources from a set of resources allocated to the target coverage enhancement level. The first device is further caused to transmit, using the subset of resources, a preamble for an uplink transmission at the transmission power level.

[0005] In a second aspect, a second device is provided. The second device comprises at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the second device to generate a configuration of a random access channel. The configuration indicates at least resources allocated to a plurality of coverage enhancement levels. The second device is further caused to transmit, to a first device, the configuration. The second device is further caused to receive, from the first device, a preamble for an uplink transmission at a transmission power level using a subset of resources, the subset of resources being determined based on the configuration.

[0006] In a third aspect, a method is provided. The method includes receiving, at a first device from a second device, a configuration of a random access channel, the configuration indicating resources allocated to a plurality of coverage enhancement levels. The method also includes determining a target coverage enhancement level from the plurality of coverage enhancement levels based on a measured power of a first signal received from the second device. The method also includes determining a transmission power level based on the measured power. The method also includes selecting a subset of resources from a set of resources allocated to the target coverage enhancement level based on the configuration and the transmission power level. The method also includes transmitting a preamble for an uplink transmission using the subset of resources at the transmission power level.

[0007] In a fourth aspect, a method is provided. The method includes generating, at a second device, a configuration of a random access channel. The configuration indicates resources allocated to a plurality of coverage enhancement levels. The method also includes transmitting the configuration to a first device. The method also includes receiving a preamble for an uplink transmission from the first device using a subset of resources at a transmission power level, the subset of resources being determined based on the configuration.

[0008] In a fifth aspect, an apparatus is provided. The apparatus includes means for receiving, at a first device from a second device, a configuration of a random access channel, the configuration indicating resources allocated to a plurality of coverage enhancement levels; means for determining a target coverage enhancement level from the plurality of coverage enhancement levels based on a measured power of a first signal received from the second device; means for determining a transmission power level based on the measured power; means for selecting a subset of resources from a set of resources allocated to the target coverage enhancement level based on the configuration and the transmission power level; and means for transmitting a preamble for an uplink transmission using the subset of resources at the transmission power level.

[0009] In a sixth aspect, an apparatus is provided. The apparatus includes means for generating, at a second device, a configuration of a random access channel, the configuration indicating resources allocated to a plurality of coverage enhancement levels; means for transmitting the configuration to a first device; and means for receiving a preamble for an uplink transmission from the first device using a subset of resources at a transmission power level, the subset of resources being determined based on the configuration.

[0010] In a seventh aspect, a computer readable medium is provided, the computer readable medium comprising program instructions for causing an apparatus to perform at least a method according to the third or fourth aspect above.

[0011] It is to be understood that the Summary is not intended to identify key or essential features of embodiments of the disclosure, nor is it intended to limit the scope of the disclosure. Other aspects of the disclosure will become readily apparent to those skilled in the art by review of the following description. BRIEF DESCRIPTION OF DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0013] Figure 1 A schematic diagram of a communication system is shown in accordance with embodiments of the disclosure;

[0014] Figure 2 A schematic diagram of interactions between devices is shown in accordance with embodiments of the disclosure;

[0015] Figure 3 A schematic diagram of gap configuration is shown in accordance with embodiments of the disclosure;

[0016] Figure 4 A flow diagram of a method is shown in accordance with embodiments of the disclosure;

[0017] Figure 5 A flow diagram of a method is shown in accordance with embodiments of the disclosure;

[0018] Figure 6 A simplified block diagram of an apparatus suitable for implementing embodiments of the disclosure is shown; and

[0019] Figure 7 A block diagram of an example computer readable medium in accordance with some example embodiments of the disclosure is shown.

[0020] Throughout the drawings, identical or similar reference numerals can represent same or similar elements. DETAILED DESCRIPTION

[0021] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that the embodiments are described for illustrative purposes only and do not represent any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various other ways than described below.

[0022] In the following description and claims, unless otherwise defined, 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.

[0023] References in the disclosure to “one embodiment”, “an embodiment”, “example embodiments”, etc. do not necessarily all refer to the same embodiment, although they can. Furthermore, such phrases do not necessarily refer to the same embodiment, although they can. Furthermore, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the purview of one of ordinary skill in the art to effect such feature, structure, or characteristic in connection with other

[0024] It should be understood that, although the terms “first” and “second” and the like can 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. 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 associated listed terms.

[0025] 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” 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.

[0026] As used in this application, the term “circuitry” can refer to one or more or all of the following:

[0027] (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and

[0028] (b) combinations of hardware circuits and software, such as (as applicable):

[0029] (i) combinations of analog and / or digital hardware circuit(s) with software / firmware and

[0030] (ii) any portions of hardware processor(s) with software (including digital signal processors); software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and

[0031] (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 software not

[0032] required for operation, but software can not be present

[0033] The 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 that is at least partially functional and / or that is programmed. For example, if a particular element is implemented in software by a processor, the function or program code of that element is specifically intended to be included within the scope of the definition of circuitry. As another example, if an element is implemented as a combination of hardware and software, any program code or software to perform the software aspects of that element is to be included within the scope of the definition of circuitry. As yet another example, if an element is implemented as only hardware, any hardware components that realize that element are to be considered within the scope of the definition of circuitry. As a further example, if an element is implemented using processors or other integrated circuits, then (in addition to being covered by the foregoing example), implementation of that element using one or more hardware components specifically (and typically preferentially) for the function or functions enabled by that element is to be included within the scope of the definition of circuitry. For example, if a particular element is implemented in software by a processor, the function or program code of that element is specifically intended to be included within the scope of the definition of circuitry. As another example, if an element is implemented as a combination of hardware and software, any program code or software to perform the software aspects of that element is to be included within the scope of the definition of circuitry. As yet another example, if an element is implemented as only hardware, any hardware components that realize that element are to be considered within the scope of the definition of circuitry. As a further example, if an element is implemented using processors or other integrated circuits, then (in addition to being covered by the foregoing example), implementation of that element using one or more hardware components specifically (and typically preferentially) for the function or functions enabled by that element is to be included within the scope of the definition of circuitry.

[0034] As used herein, the term “communication network” refers to a network that follows any suitable communication standard, such as 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-IoT), New Radio (NR), etc. Further, communication between terminal devices and network devices in a communication network can be performed according to any suitable generation of communication protocols, 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) communication protocols, and / or any other protocols that are currently known or developed in the future. Embodiments of the present disclosure can be applied in various communication systems. In view of the rapid development in communications, it will of course be understood that future types of communication technologies and systems can be embodied in the present disclosure. The above-described systems should not be considered as limiting the scope of the present disclosure.

[0035] 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 can refer to a base station (BS) or an access point (AP), such as a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also known as gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low-power node (such as a femto, pico), etc., depending on the terminology used and the technology applied.

[0036] The term "terminal device" refers to any terminal device capable of wireless communication. By way of example, and without limitation, a terminal device can also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). A terminal device can include, but is not limited to, a mobile telephone, a cellular telephone, a smart phone, a voice over Internet Protocol (VoIP) telephone, a wireless local loop (WLL) telephone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device, such as a digital camera, a gaming terminal device, a music storage and playback appliance, a vehicular wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded equipment (LEE), a laptop mounted equipment (LME), a USB dongle, a smart device, a wireless customer-premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) such as a pair of glasses or other eyewear, a vehicle, a drone, a medical device and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or

[0037] As previously mentioned, how to improve the coverage of terminal devices remains to be further studied. A key to providing better link budget for fifth generation (5G) new radio (NR) by increasing the transmission power of terminal devices is to use uplink multiple-input multiple-output (MIMO) capabilities for both transmission power increase and uplink diversity enhancement. The transmission signal to be transmitted is the same data for all transmission paths. Each transmission path can use MIMO precoding to enable independent reception at the network device. Each transmission path can transmit at a rate up to 24 dBm, resulting in a total radiated power of 27 dBm for two transmission paths and 30 dBm for four transmission paths. To compensate for the increased transmission power and, thus, the increased link budget, the transmissions use a lower duty cycle to minimize the total transmission power. This means that, in practice, the transmission power (and link budget) can be better for a short period of time and zero power for other periods of time.

[0038] Generally, terminal devices are limited to a transmission power of 24 dBm due to specific absorption rate (SAR) regulatory specifications. Network devices are not subject to SAR limitations and generally use a higher transmission power in the downlink. Thus, uplink connections are generally the limited link due to the uplink power limitation.

[0039] Internet of Things (IoT) use cases are typically uplink centric and require a large link budget to enable low power wide area connectivity. In order for 5G NR to be able to support the same use cases and be competitive compared to NB-IoT, better link budget is needed.

[0040] Other use cases supported by 5G NR can also benefit from enhanced link budget, e.g. voice services. The problem is that critical voice services can be limited by the 5G NR link budget and not be able to provide sufficient coverage. Enabling link budget enhancements for IoT, voice and other low data rate services can provide a more competitive solution for 5G NR.

[0041] In particular, the link budget of a terminal device during initial access can be limited at the cell edge.

[0042] Coverage enhancement or link budget enhancement has been studied and included in Long Term Evolution (LTE) for Narrow Band (NB) IoT solutions. NB-IoT mainly uses narrow band transmission and repetition to enhance the uplink budget. 2G solutions allow for transmission power up to 33 dBm. The NB-IoT solution with repetition or enhanced coding requires significant transmission delay and is not suitable for voice or delay sensitive services.

[0043] GSM solutions with high transmission power (33 dBm) and duty cycle transmission are not interesting solutions as terminal device power amplification (PA) is very expensive and power consuming. Standard PA in 5G NR devices is 24 dBm and from a device implementation point of view, any output power above 24 dBm is not supported at the moment.

[0044] According to embodiments of the disclosure, a network device transmits a configuration of a random access channel and a terminal device determines coverage enhancement and power boosting based on the configuration and a measured received power. Thus, collisions between terminal devices are reduced.

[0045] Figure 1 A schematic diagram of a communication system in which embodiments of the disclosure can be implemented is shown. The communication system 100 comprises devices 110-1, 110-2,..., 110-N (which can be referred to collectively as "devices 110") as part of a communication network. The communication system 100 also comprises a device 120. One or more devices are associated with and covered by a cell. It will be appreciated that Figure 1The number of devices and cells shown is given for illustrative purposes and is not meant to be limiting. The communication system 100 can include any suitable number of devices and cells. In the communication system 100, the devices 110 and 120 can communicate data and control information with each other. In the case where the device 110 is a terminal device and the device 120 is a network device, the link from the device 120 to the device 110 is called downlink (DL) and the link from the device 110 to the device 120 is called uplink (UL). Figure 1 The number of devices shown is given for illustrative purposes and is not meant to be limiting.

[0046] Communication in the communication system 100 can be implemented according to any suitable communication protocol(s), including but not limited to: first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), fifth generation (5G), and the like cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocol that is currently known or developed in the future. Moreover, communication can utilize any suitable wireless communication techniques, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplexing (FDD), time division duplexing (TDD), multi-input multi-output (MIMO), orthogonal frequency division multiple access (OFDMA), and / or any other techniques that are currently known or developed in the future.

[0047] Figure 2 A diagram illustrating interactions 200 between devices according to embodiments of the present disclosure is shown. The interactions 200 can be implemented at any suitable device. For illustrative purposes only, the interactions 200 are described as being implemented at the terminal device 110-1 and the network device 120.

[0048] The network device 120 generates 2005 a configuration of a random access channel (RACH). The configuration indicates resources allocated to different coverage enhancement levels (CEIs). For example, the resources can be frequency domain resources. The resources can also be time domain resources. Alternatively or additionally, the resources can comprise one or more preamble indices. The term "coverage enhancement" as used herein refers to an enhanced coverage functionality that can be used by a terminal device that meets certain criteria (e.g., received power is below a threshold) to access a cell. This is a radio access network (RAN) feature based on repetition of messages or transmissions between the terminal device and the network device. A single transmission block is transmitted over multiple subframes, providing higher transmission energy per information bit for a given transmission power. The coverage enhancement requirement can be a function of or can be associated with the radio link conditions of a particular device. A wireless system can implement CE techniques to improve the likelihood of successful communication with a wireless device. In some cases, a wireless system can support different CE levels (also referred to as coverage range extensions), each of which can provide a different amount of CE.

[0049] There can be one or more transmission power levels in a CEI. The transmission power levels can include power levels for normal transmissions. The transmission power can also include power levels for power boosted transmissions (e.g., power levels that exceed the normal maximum output power). The configuration can indicate different subsets of resources allocated to different transmission power levels. The network device 120 can reserve a subset of resources in the set of resources for power boosted transmissions. For example, the network device 120 can reserve a first subset of resources (e.g., time frequency or preamble resources) for normal transmissions, a second subset of resources for 0-2 dB power boosting, and a third subset of resources for 2-4 dB power boosting.

[0050] The network device 120 transmits 2010 the configuration to the terminal device 110-1. The configuration can be transmitted in system information. The configuration can also include information about the number of antennas used for power boosted initial access. Alternatively or additionally, the configuration can include information about selection of a power boosting offset.

[0051] The terminal device 110-1 can measure 2015 the power of a signal received from the network device 120. For example, the terminal device 110-1 can measure a reference signal received power (RSRP). The terminal device 110-1 determines 2020 a CEI based on the measured power. The terminal device 110-1 determines 2025 a transmission power level based on the measured power. For example, if the measured power indicates that no power boosting is needed, the terminal device 110-1 can determine a power level for normal transmissions. Alternatively or additionally, the terminal device 110-1 can determine a power level for power boosting.

[0052] Terminal device 110-1 selects 2030 a subset of resources based on the transmission power level and the configuration. For example, if the transmission power level is for power boosting, terminal device 110-1 can select resources within the set of resources that are allocated for power boosted transmissions. For example, if the transmission power level is for normal transmissions, terminal device 110-1 can select a first subset of resources for normal transmissions. If the transmission power level is for 0-2 dB of power boosting, terminal device 110-1 can select a second subset of resources. If the transmission power level is for 2-4 dB of power boosting, terminal device 110-1 can select a third subset of resources. In this way, an appropriate transmission power can be selected.

[0053] Terminal device 110-1 transmits 2035 a preamble of an uplink transmission using the subset of resources at the transmission power level. For example, terminal device 110-1 can transmit a message 1 in a four-step RACH procedure. In other embodiments, the terminal device can transmit a message A in a two-step RACH procedure. If the transmission power level is for normal transmissions, terminal device 110-1 can transmit a normal preamble. If power boosting is required, terminal device 110-1 can transmit a preamble for power boosting.

[0054] Network device 120 can determine 2037 the transmission power level based on the preamble. For example, if the preamble is for power boosting, network device 120 can determine that the transmission power level is a power boosted level.

[0055] Network device 120 can determine 2040 a gap between a set of transmission repetitions on an uplink shared channel. Depending on the network configuration, the gap can be between every N / 2 repetitions or every N / 4 repetitions. In some embodiments, network device 120 can determine a gap for power boosted transmissions to ensure that a duty cycle limit (i.e., a proportion of time that a device is allowed to transmit at a particular power level) is maintained during random access. In this case, multiple starting transmission points can be defined to minimize collisions between terminal devices for power boosted transmissions. As shown, network device 120 can determine gaps 3010-1, 3010-2, and 3010-3 and gaps 3030-1, 3030-2, and 3030-3. In this way, overall power requirements can be maintained. If a preamble transmission requires multiple repetitions, for power boosted transmissions, the repetitions need to be scheduled with some gaps to maintain the duty cycle limit required to keep the overall average transmission power within the limit for the duration. This requires gaps between power boosted transmissions. These gaps, as well as the starting offset of different power boosted (PB) preamble transmissions, can be configured. The starting offset configuration allows multiplexing of different PB transmissions with reduced collisions. Figure 3

[0056] ​The network device 120 can determine 2045 a number of repetitions based on the received preamble. In some embodiments, the network device 120 can adjust repetitions of a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) associated with a transmission based on the received CEL. For example, if the network device 120 receives a preamble for power boosting, the downlink repetitions need to be higher than the number of repetitions used by the network device 120 for normal coverage.

[0057] In some embodiments, in the case of a four-step RACH procedure, the network device 120 can decide to apply power boosting for a message 3 transmission. In this case, the message 3 transmission should start a particular set of subframes from the RACH transmission to maintain the duty cycle limit. The network device 120 can determine 2047 a duty cycle offset. As shown, the network device 120 can determine an offset 3050 for the terminal device 110-1 and a zero offset for the terminal device 110-2. In this way, collisions between terminal devices can be reduced. Figure 3

[0058] The network device 120 can send 2050 a response to the terminal device 110-1. In some embodiments, the response can indicate whether power boosting applies to the uplink transmission. The response can include one or more of a starting offset for transmissions on an uplink shared channel, a target transmission power level on the uplink shared channel, or a duty cycle offset for transmissions on the uplink shared channel. The response (e.g., message 2) can indicate via a single bit in a scheduling grant whether power boosting is to be applied for the uplink grant of message 3 and whether the terminal device 110-1 should apply a duty cycle offset. If the random access response (RAR) is scheduled after a sufficient delay after the preamble for power boosting is received, no additional duty cycle limit is needed for message 3. The network device 120 can include this additional indication. In the case of a two-step RACH procedure, the response can be message B.

[0059] ​In some embodiments, if the terminal device 110-1 selects normal power transmission and if the RACH access fails after multiple times, the terminal device 110-1 can first try power boosting transmission within the same CEL, and then try RACH access from the next CEL, which can require increased repetition number corresponding to the next CEL. For example, if the terminal device 110-1 fails to receive a response for a preamble, the terminal device 110-1 can determine 2055 another transmission power level higher than the transmission power level. The terminal device 110-1 can send 2060 another preamble at the other transmission power level. If the terminal device 110-1 still fails to receive another response for the other preamble, the terminal device 110-1 can determine 2065 another CEL for sending a preamble.

[0060] Figure 4 A flowchart of a method 400 according to embodiments of the disclosure is shown. The method 400 can be implemented at any suitable device. For example, the method can be implemented at the terminal device 110.

[0061] At block 410, the terminal device 110-1 receives a configuration of a random access channel. The configuration indicates resources allocated to different coverage enhancement levels (CELs). For example, the resources can be frequency domain resources. The resources can also be time domain resources. Alternatively or additionally, the resources can include one or more preamble indices. The configuration can indicate different subsets of resources allocated to different transmission power levels.

[0062] The configuration can be transmitted in system information. The configuration can also include information about a number of antennas for power boosting initial access. Alternatively or additionally, the configuration can include information about selection of a power boosting offset.

[0063] At block 420, the terminal device 110-1 determines a CEL based on a measured power. The terminal device 110-1 can measure 2015 a power of a signal received from the network device 120. For example, the terminal device 110-1 can measure a reference signal received power (RSRP).

[0064] At block 430, the terminal device 110-1 determines a transmission power level based on the measured power. For example, if the measured power indicates that no power boosting is needed, the terminal device 110-1 can determine a power level for normal transmission. Alternatively or additionally, the terminal device 110-1 can determine a power level for power boosting.

[0065] At block 440, the terminal device 110-1 selects a subset of resources based on the transmission power level and the configuration. For example, if the transmission power level is for power boosting, the terminal device 110-1 can select resources within the set of resources that are allocated for power boosted transmissions. For example, if the transmission power level is for normal transmissions, the terminal device 110-1 can select a first subset of resources for normal transmissions. If the transmission power level is for 0-2 dB of power boosting, the terminal device 110-1 can select a second subset of resources. If the transmission power level is for 2-4 dB of power boosting, the terminal device 110-1 can select a third subset of resources.

[0066] At block 450, the terminal device 110-1 transmits a preamble of an uplink transmission using the subset of resources at the transmission power level. The preamble can be a message 1 or a message A. For example, the terminal device 110-1 can transmit a message 1 in a four-step RACH procedure. In other embodiments, the terminal device 110-1 can transmit a message A in a two-step RACH procedure. If the transmission power level is for normal transmissions, the terminal device 110-1 can transmit a normal preamble. If power boosting is needed, the terminal device 110-1 can transmit a preamble for power boosting.

[0067] In some embodiments, the terminal device 110-1 can compare the transmission power level to a threshold level. If the transmission power level exceeds the threshold level, the terminal device 110-1 can select a preamble reserved for the transmission power level based on the configuration and transmit the preamble.

[0068] If the terminal device 110-1 detects a failure of reception of a response to the preamble from the second device, the terminal device 110-1 can determine another transmission power level that is higher than the transmission power level. The terminal device 110-1 can transmit another preamble at the other transmission power level. If the terminal device 110-1 still cannot receive another response to the other preamble, the terminal device 110-1 can determine another CEL for transmitting the preamble.

[0069] In some embodiments, the terminal device 110-1 can receive information indicating a gap between a set of repeated transmissions on an uplink shared channel. The terminal device 110-1 can perform the repeated transmissions on a random access channel based on the gap.

[0070] The terminal device 110-1 can receive a response for the preamble from the network device 120 and perform another transmission on the uplink shared channel based on the response. In some embodiments, the response can indicate whether the uplink transmission can be transmitted with a higher transmission power. If the response indicates that the uplink transmission can be transmitted with a higher transmission power, the response can also include a gap for the uplink transmission and an offset for starting the uplink transmission. In some embodiments, the response includes at least one of: a starting offset for the transmission on the uplink shared channel, a target transmission power level on the uplink shared channel, a duty cycle offset for the transmission on the uplink shared channel, and / or a gap between a set of repeated transmissions on the uplink shared channel.

[0071] Figure 5 A flowchart of the method 500 is shown. The method 500 can be implemented at any suitable device. For example, the method can be implemented at the network device 120.

[0072] At block 510, the network device 120 generates a configuration of a random access channel (RACH). The configuration indicates resources allocated to different coverage enhancement levels (CELs). For example, the resources can be frequency domain resources. The resources can also be time domain resources. Alternatively or additionally, the resources can include preambles.

[0073] There can be one or more transmission power levels in one CEL. The transmission power levels can include power levels for normal transmissions. The transmission power can also include power levels for power boosting transmissions. The configuration can indicate different subsets of resources allocated to different transmission power levels. The network device 120 can reserve a subset of resources in the set of resources for power boosting transmissions. For example, the network device 120 can reserve a first subset of resources for normal transmissions, a second subset of resources for 0-2 dB power boosting, and a third subset of resources for 2-4 dB power boosting.

[0074] At block 520, the network device 120 transmits the configuration to the terminal device 110-1. The configuration can be transmitted in system information. The configuration can also include information about the number of antennas for power boosting initial access. Alternatively or additionally, the configuration can include information about the selection of power boosting offsets.

[0075] At block 530, the network device 120 receives a preamble of an uplink transmission using a subset of resources at a transmission power level. The network device 120 can determine the transmission power level based on the preamble. For example, if the preamble is for power boosting, the network device 120 can determine that the transmission power level is a power boosting level.

[0076] In some embodiments, network device 120 can determine a gap between a set of repeated transmissions on the uplink shared channel. In some embodiments, network device 120 can determine a gap for power boosting transmissions to ensure that the duty cycle limit is maintained during random access. In this case, multiple starting transmission points can be defined to minimize collisions between terminal devices for power boosting transmissions.

[0077] Network device 120 can determine the number of repetitions based on the received preamble. In some embodiments, network device 120 can adjust the repetitions of the physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) associated with the transmission based on the received CEL. For example, if network device 120 receives a preamble for power boosting, the downlink repetitions need to be higher than the number of repetitions network device 120 uses for the CEL.

[0078] In some embodiments, in the case of a four-step RACH procedure, network device 120 can decide to apply power boosting for the message 3 transmission. In this case, the message 3 transmission should start a particular set of subframes from the RACH transmission to maintain the duty cycle limit. Network device 120 can determine a 2047 duty cycle offset. As shown, network device 120 can determine an offset 3050 for terminal device 110-1 and a zero offset for terminal device 110-2. In this way, collisions between terminal devices can be reduced. Figure 3

[0079] Network device 120 can send a response to terminal device 110-1. The response can include one or more of the following: a starting offset for transmissions on the uplink shared channel, a target transmission power level on the uplink shared channel, or a duty cycle offset for transmissions on the uplink shared channel. In the case of a four-step RACH procedure, the response (e.g., message 2) can indicate via a single bit in the scheduling grant whether power boosting is to be applied for the uplink grant for message 3 and whether terminal device 110-1 should apply a duty cycle offset. If the RAR is scheduled after a sufficient delay after receiving the preamble for power boosting, no additional duty cycle limit is needed for message 3. Network device 120 can include this additional indication. In the case of a two-step RACH procedure, the response can be message B.

[0080] In some embodiments, an apparatus (e.g., terminal device 110) for performing method 400 can include respective means for performing the corresponding steps of method 400. These means can be implemented in any suitable manner. For example, it can be implemented by circuitry or software modules.

[0081] ​In some embodiments, the apparatus includes means for receiving, from the second device, a configuration of a random access channel, the configuration indicating resources allocated to a plurality of coverage enhancement levels; means for determining, from the plurality of coverage enhancement levels, a target coverage enhancement level based on a measured power of a first signal received from the second device; means for determining a transmission power level based on the measured power; means for selecting, based on the configuration and the transmission power level, a subset of resources from a set of resources allocated to the target coverage enhancement level; and means for transmitting, using the subset of resources, a preamble of an uplink transmission at the transmission power level.

[0082] In some embodiments, the means for transmitting the preamble includes means for comparing the transmission power level to a threshold level; means for selecting, based on the configuration, a preamble reserved for the transmission power level if it is determined that the transmission power level exceeds the threshold level; and means for transmitting the preamble.

[0083] In some embodiments, the apparatus includes means for selecting, in response to detecting a failure of reception of a response to the preamble from the second device, another transmission power level that is higher than the transmission power level; means for selecting another subset of resources based on the other transmission power level and the configuration; and means for transmitting, with the other subset of resources, another preamble at the other transmission power level.

[0084] In some embodiments, the apparatus includes means for selecting, in response to detecting a failure of reception of another response to the other preamble from the second device, another enhancement level from the plurality of coverage enhancement levels.

[0085] In some embodiments, the apparatus includes means for receiving, from the second device, information indicating a gap between a set of repeated transmissions on an uplink shared channel; and means for performing the repeated transmissions on the uplink shared channel based on the gap.

[0086] In some embodiments, the apparatus includes means for receiving, from the second device, a response to the preamble, the response indicating whether a power boost applies to the uplink transmission; and means for transmitting, based on the response, a second signal on an uplink shared channel.

[0087] In some embodiments, if the power boost applies to the uplink transmission, the response includes at least one of a starting offset for transmissions on the uplink shared channel access channel, a target transmission power level on the uplink shared channel, a duty cycle offset for transmissions on the uplink shared channel, and / or a gap between a set of repeated transmissions on the uplink shared channel.

[0088] In some embodiments, the resources include at least one of a time domain resource, a frequency domain resource, and / or a preamble index.

[0089] In some embodiments, the first device comprises a terminal device and the second device comprises a network device.

[0090] In embodiments, an apparatus (e.g., network device 120) for performing method 500 can include respective means for performing the corresponding steps in the method 500. These means can be implemented in any suitable manner. For example, it can be implemented by circuitry or software modules.

[0091] In some embodiments, the apparatus comprises means for generating, at the second device, a configuration of a random access channel, the configuration indicating resources allocated to a plurality of coverage enhancement levels; means for transmitting the configuration to the first device; and means for receiving a preamble for an uplink transmission from the first device using a subset of resources, the subset of resources determined based on the configuration, at a transmission power level.

[0092] In some embodiments, the means for receiving the preamble comprises means for determining that the transmission power level exceeds a threshold level if it is determined that the preamble is reserved for the transmission power level.

[0093] In some embodiments, the apparatus comprises means for generating information indicating a gap between a set of repeated transmissions on an uplink shared channel; and means for transmitting the information to the first device.

[0094] In some embodiments, the apparatus comprises means for generating a response to the preamble based on the transmission power level, the response indicating whether a power boost is applicable to the uplink transmission; and means for transmitting the response to the first device.

[0095] In some embodiments, if the power boost is applicable to the uplink transmission, the response comprises at least one of: a starting offset for a transmission on an uplink shared channel access channel, a target transmission power level on the uplink shared channel, a duty cycle offset for a transmission on the uplink shared channel, and / or a gap between a set of repeated transmissions on the uplink shared channel.

[0096] In some embodiments, the resources comprise at least one of: time domain resources, frequency domain resources, and / or a preamble index.

[0097] In some embodiments, the first device comprises a terminal device and the second device comprises a network device.

[0098] Figure 6 is a simplified block diagram of a device 600 suitable for implementing embodiments of the present disclosure. The device 600 can be provided to implement a communication device, for example as Figure 1The terminal device 110 or the network device 120 is shown. As shown, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processors 610, and one or more communication modules 640 coupled to the processors 610.

[0099] The communication module 640 is for bidirectional communication. The communication module 640 has at least one antenna to facilitate communication. The communication interface can represent any interface necessary to communicate with other network elements.

[0100] The processor 610 can be of any type suitable to the local technical network and can include, by way of non-limiting example, one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multi-core processor architectures, as non-limiting examples. The device 600 can have multiple processors such as a dedicated integrated circuit chip that is time-slaved to a clock that is synchronized with a master processor.

[0101] The memory 620 can include one or more non-transitory memories and one or more transitory memories. Examples of non-transitory memories include, but are not limited to, read-only memory (ROM) 624, electrically programmable read only memory (EPROM), flash memory, a hard disk, a compact disc (CD), a digital video disc (DVD), and other magnetic and / or optical storage. Examples of transitory memories include, but are not limited to, random access memory (RAM) 622 and other volatile memories that do not persist in the absence of power.

[0102] The computer program 630 includes computer-executable instructions executed by the associated processor 610. The program 630 can be stored in the ROM 624. The processor 610 can perform any suitable action and processing by loading the program 630 into the RAM 622.

[0103] Embodiments of the present disclosure can be implemented by means of the program 1530, such that the device 1500 can perform any process of the present disclosure as discussed with reference to Figure 2 and Figure 5 Embodiments of the present disclosure can also be implemented by means of hardware or a combination of software and hardware.

[0104] In some example embodiments, the program 630 can be tangibly embodied in a computer readable medium, which can be included in the device 600, such as in the memory 620, or in another storage device accessible by the device 600. The device 600 can load the program 630 from the computer readable medium into the RAM 622 for execution. The computer readable medium can include any type of tangible non-transitory memory, such as ROM, EPROM, flash memory, a hard disk, a CD, a DVD, and the like. Figure 7An example of a computer readable medium 700 in the form of a CD or DVD is shown. The computer readable medium has stored thereon the program 630.

[0105] It should be appreciated that future networks can utilize network function virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into entities that can be operated and interconnected as needed to provide services. A virtualized network function (VNF) can comprise one or more virtual machines that use standard or general type servers rather than customized hardware to execute computer program codes. Cloud computing or data storage can also be used. In radio communications, this can mean that node operations are at least partly executed in a central / centralized unit CU (e.g. server, host or node) that is operably coupled to a distributed unit DU (e.g. radio head / node). The node operations can also be distributed between a plurality of servers, nodes or hosts. It should also be understood that the allocation of duties between the core network operations and the base station operations can differ depending on implementation.

[0106] In one embodiment, the server can generate a virtual network through which the server communicates with the distributed unit. Generally, a virtual network can involve a process of combining hardware and software network resources and network functions into a single software-based managed entity (virtual network). Such a virtual network can provide flexible distribution of operations between the server and the radio head / node. In practice, any digital signal processing tasks can be performed in the CU or the DU, and the border of duty shift between the CU and the DU can be chosen according to implementation.

[0107] Thus, in one embodiment, a CU-DU architecture is implemented. In this case, the device 600 can be comprised in a central unit (e.g. control unit, edge cloud server, server) that is operably coupled (e.g. via a wireless or wired network) to a distributed unit (e.g. remote radio head / node). That is, the central unit (e.g. edge cloud server) and the distributed unit can be separate apparatuses that communicate with each other via a radio path or via a wired connection. Alternatively, they can be in the same entity that communicates via a wired connection or the like. The edge cloud or edge cloud server can serve multiple distributed units or radio access networks. In one embodiment, at least some of the described procedures can be performed by the central unit. In another embodiment, the device 600 can instead be comprised in the distributed unit, and at least some of the described procedures can be performed by the distributed unit.

[0108] In one embodiment, execution of at least some of the functionality of the device 600 can be shared between two physically separate devices forming one operational entity (a CU and a DU). Thus, the apparatus can be seen as depicting an operational entity comprising one or more physically separate devices for performing at least some of the described processes. In one embodiment, such a CU-DU architecture can provide a flexible operational distribution between the CU and the DU. In practice, any digital signal processing task can be performed in the CU or the DU, and the border of responsibility shift between the CU and the DU can be chosen according to implementation. In one embodiment, the device 600 controls the execution of the processes regardless of the location of the apparatus and regardless of where the processes / functions are executed.

[0109] In general, the various embodiments of the present disclosure can be implemented using hardware or special-purpose circuits, software, logic or any combination thereof. Some aspects can be implemented using hardware, while other aspects can be implemented using software or firmware that is executed by a controller, microprocessor or other computing device. Although the various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein can be implemented using hardware, software, firmware, special-purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0110] The present disclosure also provides at least one computer program product having a tangible computer-readable storage medium having stored thereon instructions that, when executed by a processor of a device, operate to perform at least one of the methods 400-600 described above with reference to Figures 3-6 The program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that implement particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules can be combined or split between program modules as desired. Machine executable instructions for a program module can be executed within a local or distributed device. In a distributed device, program modules can be located in both local and remote storage media.

[0111] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, causes the machine to perform the described functions / operations specified in the flowcharts and / or block diagrams. The program code can be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0112] In the context of the present disclosure, computer program code or related data can be carried by any suitable carrier to enable a device, apparatus, or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, and the like.

[0113] The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable medium can include, but is not limited to, 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 one or more of 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.

[0114] Moreover, while operations can be described as following a specific sequence, this should not be understood as requiring such a specific sequence rather, activities associated with the operations could be performed in any order, unless otherwise specifically noted. In some cases, activities can be performed in parallel. Also, while the above discussion has included specific implementation details, these should not be construed as limiting the scope of the disclosure, but rather as describing features that can be specific to certain 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 sub-combination.

[0115] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject of the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claims.

Claims

1. A first device, comprising: at least one processor; as well as 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 to: receiving a configuration of a random access channel from a second device, the configuration indicating resources allocated to a plurality of coverage enhancement levels; determining a target coverage enhancement level from the plurality of coverage enhancement levels based on a measured power of the first signal received from the second device; determining a transmission power level based on the measured power; selecting a subset of resources from a set of resources allocated to the target coverage enhancement level based on the configuration and the transmit power level; transmitting a preamble for an uplink transmission at the transmit power level using the subset of resources; receiving, from the second device, information indicating a gap between a set of repeated transmissions on an uplink shared channel, the gap being configured to be located between every N / 2 repetitions or every N / 4 repetitions, the indication also including a gap for power boost transmissions to ensure that duty cycle limits are maintained during random access; performing the repeated transmission on the uplink shared channel based on the gap; receiving, from the second device, a starting offset for transmission on the uplink shared channel, the starting offset being a specific subframe set selected from a plurality of starting transmission points to maintain duty cycle constraints and minimize collisions between terminal devices; Performing uplink transmission based on the starting offset; selecting another transmission power level higher than the transmission power level in response to detecting a failure in reception of a response to the preamble from the second device; selecting another subset of resources based on the another transmit power level and the configuration; and Another preamble is sent at the another transmission power level using the another subset of resources.

2. The first device according to claim 1, wherein the first device is further configured to: In response to detecting a failure of receipt of another response to the further preamble from the second device, another enhancement level is selected from the plurality of coverage enhancement levels.

3. The first device according to claim 1, wherein the first device is further configured to: receiving a response to the preamble from the second device, the response indicating whether a power boost is applicable for the uplink transmission; and A second signal is sent on an uplink shared channel based on the response.

4. The first device of claim 3 , wherein if the power boost is applicable to the uplink transmission, the response comprises at least one of: a starting offset for transmission on said uplink shared channel, a target transmission power level on the uplink shared channel, a duty cycle offset for transmissions on the uplink shared channel, and / or A gap between a set of repeated transmissions on the uplink shared channel. The first device according to claim 1 , wherein the resource comprises at least one of the following: a time domain resource, a frequency domain resource and / or a preamble index. The first device according to claim 1 , wherein the first device comprises a terminal device, and the second device comprises a network device.

7. A method for communication, comprising: receiving, at a first device, a configuration of a random access channel from a second device, the configuration indicating resources allocated to a plurality of coverage enhancement levels; determining a target coverage enhancement level from the plurality of coverage enhancement levels based on a measured power of the first signal received from the second device; determining a transmission power level based on the measured power; selecting a subset of resources from a set of resources allocated to the target coverage enhancement level based on the configuration and the transmit power level; transmitting a preamble for an uplink transmission at the transmit power level using the subset of resources; receiving, from the second device, information indicating a gap between a set of repeated transmissions on an uplink shared channel, the gap being configured to be located between every N / 2 repetitions or every N / 4 repetitions, the indication also including a gap for power boost transmissions to ensure that duty cycle limits are maintained during random access; performing the repeated transmission on the uplink shared channel based on the gap; receiving, from the second device, a starting offset for transmission on the uplink shared channel, the starting offset being a specific subframe set selected from a plurality of starting transmission points to maintain duty cycle constraints and minimize collisions between terminal devices; Performing uplink transmission based on the starting offset; selecting another transmission power level higher than the transmission power level in response to detecting a failure in reception of a response to the preamble from the second device; selecting another subset of resources based on the another transmit power level and the configuration; and Another preamble is sent at the another transmission power level using the another subset of resources.

8. The method according to claim 7, further comprising: In response to detecting a failure to receive another response to the another preamble from the second device, another enhancement level is selected from the plurality of coverage enhancement levels.

9. The method according to claim 7, further comprising: receiving a response to the preamble from the second device, the response indicating whether a power boost is applicable for the uplink transmission; as well as A second signal is sent on an uplink shared channel based on the response.

10. The method of claim 9, wherein if the power boost is applicable to the uplink transmission, the response comprises at least one of: a starting offset for transmission on said uplink shared channel, a target transmission power level on the uplink shared channel, a duty cycle offset for transmissions on the uplink shared channel, and / or A gap between a set of repeated transmissions on the uplink shared channel. The method according to claim 7 , wherein the resource comprises at least one of the following: a time domain resource, a frequency domain resource and / or a preamble index.

12. The method of claim 7, wherein the first device comprises a terminal device, and the second device comprises a network device.

13. A computer-readable storage medium comprising program instructions stored thereon, which, when executed by a device, cause the device to perform the method according to any one of claims 7 to 12.

14. An apparatus comprising means for performing the method according to any one of claims 7 to 12.

15. An apparatus comprising circuitry configured to cause the apparatus to perform a process according to any one of claims 7 to 12.

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