CN111357376B - Machine type communication physical downlink control channel commands - Google Patents

Abstract

Various communication systems may benefit from improved random access related communications. For example, certain embodiments may benefit from improved physical downlink control channel commands in enhanced machine type communications. In some embodiments, a method may include: an instruction to initiate random access is received at a user equipment from a network entity. The method may further comprise: after receiving the instruction, determining, at the user equipment, a timing for transmitting the random access preamble based on the repetition value of the physical downlink control channel. The repetition value may be used by the user equipment and another repetition value is used for the instruction to start random access. Additionally, the method may include: the random access preamble is transmitted from the user equipment to the network entity on the physical random access channel using the determined timing.

Description

Machine Type Communications Physical Downlink Control Channel Commands

background

field

Various communication systems can benefit from improved random access related communications. For example, certain embodiments may benefit from improved physical downlink control channel order in enhanced machine type communications.

Description of related technologies

In 3rd Generation Partnership Project (3GPP) technologies such as Long Term Evolution (LTE) and Long Term Evolution-Advanced (LTE-A), the random access procedure is typically used to perform random access via the Physical Random Access Channel (PRACH) or narrowband physical random access. The access channel (NPRACH) connects user equipment to the network. Although the random access procedure is usually triggered or initiated by the user equipment, in some cases, the random access procedure may be triggered or initiated by the network. The random access procedure is initiated at the network when the user equipment is out of sync with the network and when there is downlink data transmission that the network needs to send to the user equipment.

The PDCCH command is a process used by the network to initiate a random access procedure at the user equipment, thereby synchronizing the user equipment's uplink and/or downlink transmissions with network entities located within the network. The initiated random access procedure may be a non-contention random access procedure. The user equipment that receives the PDCCH order may send a random access preamble to the network entity using the preamble index included in the PDCCH order. The network entity then responds to the random access preamble with a random access response message including the new timing advance value used by the user equipment to synchronize uplink and/or downlink transmissions.

Enhanced machine type communication is communication between user devices that requires little human intervention. The machine type communications device is capable of receiving PDCCH commands from the network entity through the MTC Physical Downlink Control Channel (MPDCCH) or the Narrowband Physical Downlink Control Channel (NPDCCH). Specifically, a machine type communications device may use PDCCH commands to synchronize its uplink transmissions with the network.

Contents of the invention

According to certain embodiments, an apparatus may include at least one memory including computer program code and at least one processor. The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to receive at least an instruction from a network entity to initiate a random access. The at least one memory and computer program code may also be configured to, together with the at least one processor, cause the apparatus to determine, at least after receiving the instruction, a random access preamble for transmission based on a repeat value of a physical downlink control channel. Timing. This repeated value may be used by the user equipment, while the other repeated value is used for the instruction to start random access. Additionally, the at least one memory and computer program code may also be configured to, together with the at least one processor, cause the apparatus to transmit at least the random access preamble from the user equipment to the network on the physical random access channel using the determined timing. entity.

In some embodiments, a method may include receiving, at a user equipment, an instruction from a network entity to initiate random access. The method may further include: after receiving the instruction, determining, at the user equipment, timing for transmitting the random access preamble based on a repetition value of the physical downlink control channel. This repeated value may be used by the user equipment, while the other repeated value is used for the instruction to start random access. Additionally, the method may include transmitting a random access preamble from the user equipment to the network entity on a physical random access channel using the determined timing.

In some embodiments, an apparatus may include means for receiving, at a user equipment, an instruction from a network entity to initiate a random access. The apparatus may further include: a component for determining, at the user equipment, the timing of transmitting the random access preamble based on the repetition value of the physical downlink control channel after receiving the instruction. This repeated value may be used by the user equipment, while the other repeated value is used for the instruction to start random access. Additionally, the apparatus may comprise means for transmitting a random access preamble from the user equipment to the network entity on a physical random access channel using the determined timing.

According to certain embodiments, a non-transitory computer-readable medium encodes instructions that, when executed in hardware, perform a process. The process may include receiving, at the user equipment, an instruction from the network entity to start random access. The process may further include: after receiving the instruction, determining, at the user equipment, a timing for transmitting the random access preamble based on a repeated value of the physical downlink control channel. This repeated value may be used by the user equipment, while the other repeated value is used for the instruction to start random access. Additionally, the process may include transmitting a random access preamble from the user equipment to the network entity on a physical random access channel using the determined timing.

According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include receiving, at the user equipment, an instruction from the network entity to start random access. The process may further include: after receiving the instruction, determining, at the user equipment, a timing for sending the random access preamble based on a repetition value of the physical downlink control channel. This repeated value may be used by the user equipment, while the other repeated value is used for the instruction to start random access. Additionally, the process may include transmitting a random access preamble from the user equipment to the network entity on a physical random access channel using the determined timing.

According to certain embodiments, an apparatus may include at least one memory including computer program code and at least one processor. The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to transmit instructions to the user equipment to initiate random access using at least another number of repetitions different from the repetition value. The at least one memory and computer program code may be further configured to, together with the at least one processor, cause the apparatus to receive data from a user via a physical random access channel in accordance with at least a timing for transmitting a repeat value-based random access preamble. The device's random access preamble.

In some embodiments, a method may include sending an instruction to start random access from the network entity to the user equipment using another repetition number different from the repetition value. The method may further comprise receiving a random access preamble from the user equipment via a physical random access channel at the network entity according to the timing for transmitting the repetition value based random access preamble.

In some embodiments, an apparatus may include means for sending an instruction to start random access from the network entity to the user equipment using another number of repetitions different from the repetition value. The apparatus may further comprise means for receiving a random access preamble from the user equipment via a physical random access channel at the network entity according to the timing for transmitting the repetition value based random access preamble.

According to some embodiments, a non-transitory computer-readable medium encodes instructions that, when executed in hardware, perform a process. The process may include sending an instruction to start random access from the network entity to the user equipment using another repetition number different from the repetition value. The process may further include receiving, at the network entity, a random access preamble from the user equipment via a physical random access channel according to the timing used to transmit the repetition value based random access preamble.

According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include sending an instruction to start random access from the network entity to the user equipment using another repetition number different from the repetition value. The process may further include receiving, at the network entity, a random access preamble from the user equipment via a physical random access channel according to the timing used to transmit the repetition value based random access preamble.

Description of the drawings

For a proper understanding of the invention, reference should be made to the accompanying drawings, in which:

Figure 1 shows an example of the timing relationship between PDCCH orders and PRACH according to certain embodiments.

Figure 2 illustrates an example of a flowchart in accordance with certain embodiments.

Figure 3 illustrates an example of a flowchart in accordance with certain embodiments.

Figure 4 illustrates an example of a system in accordance with certain embodiments.

Detailed ways

Certain embodiments may involve the relationship between instructions to start random access, such as MPDCCH/NPDCCH/PDCCH orders, and timing for transmitting random access preambles, such as PRACH/NPRACH transmission. MPDCCH, NPDCCH and/or PDCCH may generally be referred to as PDCCH below, and NPRACH and/or PRACH may generally be referred to as PRACH below. Although some embodiments refer to MPDCCH, NPDCCH, PDCCH, NPRACH and PRACH, certain other embodiments may use any other type of channel provided by 3GPP or any other standards setting body. Additionally, while some embodiments described below relate to 3GPP LTE and LTE-A, other embodiments may be applied to 3GPP fifth generation (5G) or new radio (NR) technologies.

Section 6.1.1 of 3GPP TS 36.213 describes that when the random access procedure is initiated by the PDCCH command in subframe n and/or the reception of the PDCCH command in subframe n ends, the UE in the first subframe n+k ₂ (k ₂ ≥ 6), the random access preamble is sent, in which PRACH resources are available. In other words, 3GPP TS 36.213 describes that PRACH resources are available 6 or more subframes after subframe n. A UE described in 3GPP TS 36.213 is a non-bandwidth limited (BL) or non-coverage enhanced (CE) user equipment (UE). BL/CE UE may be a machine type communication device. Section 16.3.2 of 3GPP TS 36.213 describes a similar process for Narrowband Internet of Things (NB-IoT). 3GPP TS 36.213 is incorporated by reference in its entirety.

In some embodiments, the PDCCH may be an enhanced machine type communications (eMTC) PDCCH (MPDCCH) or NPDCCH. Hereinafter, the MPDCCH may be simply referred to as PDCCH. Because PRACH/NPRACH transmission is triggered by a PDCCH command, the timing of MPDCCH/NPDCCH reception determines when PRACH/NPRACH transmission may occur. As discussed above, the PDCCH order ends in subframe n, which means that the timing of the PRACH transmission can be determined based on the time the PDCCH order ends. However, since the number of MPDCCH repetitions is not known by the UE, but only by the network, the UE does not know when the PDCCH command ends and when the PRACH transmission starts.

PDCCH commands can be transmitted to the UE in various different formats. For example, one such format may be Downlink Control Information (DCI) format 6-1A. Another example could be DCI format 6-1B or N1, where N1 could be the NB-IoT DCI format. The DCI corresponding to the PDCCH order may be carried by the MPDCCH. As described in section 5.3.3.1.12 of 3GPP TS36.212, Format 6-1A is valid only if the Format 6-1A cyclic redundancy check (CRC) is scrambled by the Cell Radio Network Temporary Identity (C-RNTI). It can be used for the random access process initiated by the PDCCH command. 3GPP TS 36.212 is incorporated by reference in its entirety. The remaining fields in the 6-1A format may include resource block assignments determined by the following equation: bits, where/> Represents the downlink bandwidth configuration, expressed in the number of resource blocks. In addition, the 6-1A format may include a 6-bit preamble index, a 4-bit PRACH mask index, and 2 bits for starting the coverage enhancement level. All remaining bits in DCI format 6-1A assigned by compact scheduling for the physical downlink shared channel may be set to zero.

Section 5.7.1 of 3GPP TS 36.211 further describes that for BL/CE UEs such as MTC devices, only a subset of subframes are allowed for preamble transmission and are also allowed to be used as Repeated start subframe. /> It may be a subframe in which the UE may start sending data via the PRACH. 3GPP TS 36.211 is incorporated by reference in its entirety.

Therefore, in some embodiments, the start subframe of the PRACH transmission may be determined by the end of the repetition of the PDCCH command and the start subframe periodicity of the PRACH. However, neither DCI formats 6-1A nor 6-1B include a DCI subframe repetition number field. This means that the UE may not be informed of the ending subframe of the PDCCH order and therefore may not know the starting subframe of the PRACH transmission. This lack of understanding by the UE may lead to incorrect and conflicting operations by both the UE and the network entity sending the PDCCH order.

Certain embodiments described below may be used in any communication system in which the number of DCI subframe repetitions or the number of PDCCH command repetitions is unknown. Embodiments help ensure correct operation for eMTC PDCCH commands because it is unclear when the UE should send a PRACH in response to receipt of the command. This can help achieve common knowledge of PRACH transmission timing between the UE and the network entity.

Figure 1 shows an example of the timing relationship between PDCCH orders and PRACH transmissions in accordance with certain embodiments. In particular, Figure 1 illustrates an example of PDCCH command reception and corresponding PRACH transmission. In the example shown in Figure 1, a network entity such as an enhanced NodeB (eNB) may configure the MPDCCH 110 to have 256 repetitions of the PDCCH order. The UE may assume that the PDCCH command is capable of 256 repetitions. If the UE's decoding of the PRACH order does not reveal that the PDCCH order is capable of 256 repetitions, the UE may not transmit on the PRACH.

The eNB may expect the UE to transmit PRACH between subframe numbers 128 to 255 of the second search space. Despite the eNB's expectations, the UE may be able to correctly decode the MPDCCH in the first MPDCCH candidate with 64 repetitions. When the UE correctly decodes the MPDCCH in the first MPDCCH with 64 repetitions, the UE may transmit the PRACH between subframe numbers 128 to 255 of the first MPDCCH search space. In another example, the UE may transmit the PRACH from subframe numbers 0 to 127 of the second MPDCCH search space and/or from subframe numbers 128 to 255 of the second MPDCCH search space. In other words, the user equipment may have two different options for transmitting on the PRACH which may not be desired by the eNB.

As can be seen in Figure 1, the eNB and the UE may have different understandings of the starting subframe of PRACH transmission. This may cause, for example, the network entity to try to decode the PRACH while the PDCCH order is still being transmitted. This is because the UE may not know subframe n, which is the subframe that marks the end of PDCCH order reception. Therefore, the implementation of network entities such as eNBs may become complex and depending on the UE implementation, possible errors may occur.

To prevent the above complexities and errors, some embodiments may improve the PDCCH order. Specifically, some embodiments may configure a repeat value to the UE in order to determine PRACH timing. For example, the repeat value could be the configured maximum repeat value (Rmax). In some embodiments, the MPDCCH repetition number or value may be 1, 2, 4, 8, 16, 32, 64, 128, or 256. Rmax may be the maximum number of repetitions configured for the UE-specific search space for MPDCCH.

In some embodiments, the UE may be informed of Rmax via the RRC parameter mPDCCH-NumRepetition or nPDCCH-NumRepetitions, which may be configured by a network entity such as an eNB. nPDCCH-NumRepetitions can be parameters used in NB-IoT. Using Rmax, certain embodiments may resolve or help prevent ambiguities between PRACH timing perceived by the eNB and UEs (such as eMTC UEs). Certain embodiments allow the UE to use repetition values, such as Rmax, independent of the repetition used by the network entity. In other words, the network entity may use the fraction of the repetition value for the PDCCH order, but may then determine the PRACH timing based on the repetition value (such as Rmax). Therefore, another number of repetitions for the PDCCH command may be different from the Rmax used for the PRACH timing hypothesis. The embodiments described above allow solving the current problem without having to extend the DCI.

Certain other embodiments may improve the PDCCH command format. Specifically, some embodiments may introduce a field to indicate the number of repetitions in the downlink control information. This field may be a DCI subframe repetition number field, and may be included in DCI format 6-1A, 6-1B, or N1. By adding this DCI subframe repetition number field, the ambiguity between PRACH or NPRACH timing perceived by the eNB and UE can be resolved.

Figure 2 illustrates an example of a flowchart in accordance with certain embodiments. In particular, Figure 2 shows a method or process performed by a UE, such as an eMTC or NB-IoT UE or enhanced coverage user equipment. In step 210, the UE may receive an instruction to start random access from the network entity. For example, the instruction to start random access may be in the form of a PDCCH command. In some embodiments, the UE may decode the PDCCH to determine an instruction to start random access, as shown in step 220. When decoding the PDCCH to determine an instruction to start random access, such as a PDCCH command, the UE may use the repeated value as a reference timing for random access. For example, repeated values may define a UE-specific search space for PDCCH. In some embodiments, the repeat value may be the configured maximum repeat value. PDCCH commands can be formatted according to DCI format 6-1A, 6-1B or N1. In some embodiments, the actual repetition value may be indicated in the downlink control information (DCI) subframe repetition number field included in the format 6-1A, 6-1B or N1 downlink control information.

In some embodiments, the repetition value assumed or used by the UE may be different from another repetition number used by the network entity to determine the repetition of an instruction to initiate random access, such as a PDCCH order. For example, the number of network uses may be the fraction of duplicate values assumed or used by the UE. In other words, the UE and the network entity may use a different number of repetitions or another repetition value for the instruction to start random access (such as the PDCCH order) than the repetition value used by the UE to determine the timing to send the random access preamble (such as the PRACH timing). repeat times.

In some embodiments, the UE may determine duplicate values. For example, the duplicate value may be determined based on messages received at the UE from a network entity such as an eNB. In another example, duplicate values may be determined based on standards set by a network operator or standards setting body. Both the UE and the network entity may be configured with or have access to duplicate values. In some embodiments, the score of duplicate values may be used by the network entity. For example, in an embodiment where the repetition value is Rmax, another repetition value used by the network entity may be Rmax/8, Rmax/4, Rmax/2 or Rmax, and the UE may use Rmax. For example, if Rmax is 256 repetitions, the repetition value used by the network entity can be 128, 64, or 32.

In step 230, the UE may determine the timing for transmitting the random access preamble, such as PRACH timing, based on the repetition value of the PDCCH. This repeated value is used by the user equipment, while the other repeated value is used for the instruction to start random access. In other words, the UE may use the assumed repetition value to determine the timing of the random access preamble, while the network may use a separate or different another repetition value for the instruction to start random access. Another repetition value for the instruction to start random access may be a fraction of the repetition value used for the timing of transmitting the random access preamble. In step 240, the UE may transmit the random access preamble from the UE to the network entity on the PRACH using the determined timing, such as PRACH timing. The transmission of the preamble from the UE to the network entity using PRACH timing can be used to synchronize the uplink transmission between the UE and the network entity. In other words, the transmission of the preamble may be part of the random access operation.

In some embodiments, transmission of the preamble may occur on the beginning subframe of the PRACH. The start subframe may be determined based on at least one of a repetition value of the PDCCH and/or a periodicity of the start subframe. For example, in some embodiments, the starting subframe of the physical random access channel is a predefined number of subframes after the ending subframe of the user equipment-specific search space of the physical downlink control channel. For example, for eMTC, the predefined number of subframes may be 6, while for NB-IoT, the predefined number of subframes may be 8. In other words, the starting subframe of PRACH may be later than subframe Rmax+6 or Rmax+8, for example. The periodicity of the starting subframe may be configured by the network entity. However, in other embodiments, the periodicity may not be configured by the network.

Figure 3 illustrates an example of a flowchart in accordance with certain embodiments. In particular, Figure 3 shows a method or process performed by a network entity such as an eNB or fifth generation or new wireless Node B (gNB). In step 310, the network entity may transmit an instruction to start random access to the UE using another repetition number different from the repetition value. Another repetition value for the instruction to start random access may be a fraction of the repetition value for the determined timing of the random access preamble. In other words, the UE may use a repeat value to transmit the random access preamble, regardless of the fact that the network entity may use a different repeat value (such as a fraction of the repeat value) to send the instruction to start random access.

The number of repetitions may be indicated in the downlink control information subframe repetition number field, which is included in the downlink control information format 6-1A, 6-1B or N1. In step 320, the network entity may receive a random access preamble from the UE via a physical random access channel according to the timing used to transmit the random access preamble, the random access preamble being based on repeated values. In other words, the UE may assume a duplicate value regardless of another duplicate value used by the network entity to send the random access instruction. Receiving the preamble may occur on the starting subframe of the PRACH and/or the starting subframe may be determined based on the maximum repetition value of the PDCCH or the periodicity of the starting subframe.

In step 330, the network entity may decode the random access preamble sent from the UE via the PRACH with a specific number of repetitions according to the coverage enhancement level of the UE. The network entity may then transmit a random access response from the network entity to the UE based on the decoded preamble, as shown in step 340. The random access response is transmitted from the network entity to the user equipment to synchronize uplink transmission between the user equipment and the network entity.

Figure 4 illustrates an example of a system in accordance with certain embodiments. It should be understood that each block in Figures 1, 2, and 3 may be implemented by various means or combinations thereof, such as hardware, software, firmware, one or more processors, and/or circuitry. In one embodiment, the system may include multiple devices, such as, for example, network entity 420 or UE 410. The system may include more than one UE 410 and more than one network entity 420, although only one network entity is shown for illustration purposes. A network entity may be a network node, access node, base station, eNB, gNB, server, host or any other access or network node discussed herein.

Each of these devices may include at least one processor or control unit or module, designated 411 and 421 respectively. At least one memory may be provided in each device, designated 412 and 422 respectively. Memory may include computer program instructions or computer code contained therein. One or more transceivers 413 and 423 may be provided, and each device may also include an antenna, shown as 414 and 424 respectively. Although only one antenna is shown, many antennas and multiple antenna elements may be provided for each device. Higher category UEs typically include multiple antenna panels. For example, other configurations of these devices may be provided. For example, network entity 420 and UE 410 may be configured for wired communications in addition to wireless communications, and in this case, antennas 414 and 424 may represent any form of communications hardware, not just antennas.

Transceivers 413 and 423 may each independently be a transmitter, a receiver, or both a transmitter and a receiver, or may be a unit or device configured for transmission and reception. In other embodiments, the network entity may have at least one separate receiver or transmitter. The transmitter and/or receiver (in terms of radio components) can also be implemented as a remote radio head, which is not located in the device itself, but is located, for example, in a pole. Operations and functionality can be performed in different entities such as nodes, hosts or servers in a flexible manner. In other words, the division of labor may vary depending on the situation. One possible use is to enable network nodes to deliver local content. One or more functionality may also be implemented as virtual application(s) in software that can run on the server.

The user device or user equipment may be a mobile station (MS) such as a mobile phone or smart phone or a multimedia device, a computer such as a tablet computer provided with wireless communication capabilities, a personal data or digital assistant (PDA) provided with wireless communication capabilities, Portable media players, digital cameras, pocket camcorders, navigation units equipped with wireless communication capabilities, or any combination thereof. In other embodiments, the UE may be a Machine Type Communication (MTC) device, an eMTC UE, or an Internet of Things device such as a sensor, instrument, or actuator that may not require human interaction.

In some embodiments, a device such as user equipment 410 or network entity 420 may include components for performing or carrying out the embodiments described above with respect to Figures 1-3. In some embodiments, a device may include at least one memory including computer program code and at least one processor. The at least one memory including computer program code may be configured to, together with the at least one processor, cause the device to perform at least any process described herein. For example, the device may be user equipment 410 or network entity 420.

Processors 411 and 421 may be embodied by any computing or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic device (PLD), field programmable gate array (FPGA), digital enhancement circuit, or similar device or a combination thereof. A processor may be implemented as a single controller, or as multiple controllers or processors.

For firmware or software, the implementation may include at least one module or unit of the chipset (eg, a process, a function, etc.). Memories 412 and 422 may independently be any suitable storage device, such as non-transitory computer-readable media. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memory may be combined with the processor on a single integrated circuit or may be separate from it. Furthermore, computer program instructions may be stored in memory and may be processed by the processor as computer program code in any suitable form, e.g., a computer program written or interpreted in any suitable programming language. The memory or data storage entity is typically internal, but may be external or a combination thereof, such as where additional storage capacity is obtained from a service provider. Storage can be fixed or removable.

Memory and computer program instructions may be configured using a processor for a particular device to cause a hardware device, such as network entity 420 or UE 410, to perform any of the processes described above (eg, see Figures 1-3). Accordingly, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer programs (such as added or updated software routines, applets, or macros), or A computer program, when executed in hardware, may perform a process, such as any of the processes described herein. In other embodiments, a computer program product may encode instructions for performing any of the processes described above, or a computer program product embodied in a non-transitory computer-readable medium may encode instructions that, when executed in hardware Perform any of the above procedures. Computer programs may be encoded in a programming language, which may be a high-level programming language such as Objective-C, C, C++, C#, Java, etc., or a low-level programming language such as machine language or assembler. Alternatively, some embodiments may be implemented entirely in hardware.

Furthermore, although FIG. 4 illustrates a system including network entity 420 and UE 410, certain embodiments may be applicable to other configurations and configurations involving additional elements, as illustrated and discussed herein. For example, there may be multiple user equipment devices and multiple network entities, or other nodes providing similar functionality, such as nodes that combine the functionality of user equipment and network entities, such as relay nodes. In addition to the communication network entity 420, the UE 410 may also be provided with various configurations for communication. For example, UE 410 may be configured for device-to-device, machine-to-machine, and/or vehicle-to-vehicle transmission.

The above embodiments may provide significant improvements to the operation of a network and/or the operation of user equipment and network entities included in the network. Specifically, certain embodiments may help prevent ambiguity between the network and the UE regarding the starting subframe of PRACH. This can help reduce the number of erroneous PRACH transmissions while simplifying PDCCH orders. This network simplification and error reduction will help reduce the number of resources used by the network, thereby significantly improving the operation of the entire network as well as the operation of the network entities included in the network and the eMTC UEs communicating with the network. Additionally, certain embodiments may help improve the uplink synchronization process between the network and the UE, which may also help reduce the amount of downtime experienced by the UE.

Features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, use of the phrase "certain embodiments," "some embodiments," "other embodiments," or other similar language throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may is included in at least one embodiment of the invention. Thus, throughout this specification, appearances of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language are not necessarily referring to the same group of embodiments, and the described The features, structures or characteristics of may be combined in any suitable manner in one or more embodiments.

One of ordinary skill in the art will readily appreciate that the invention as described above may be practiced using a different sequence of steps and/or hardware elements in different configurations than those disclosed. Therefore, while the invention has been described based on these preferred embodiments, it will be apparent to those skilled in the art that certain modifications, variations and alternative constructions will be apparent without departing from the spirit and scope of the invention. Although many of the embodiments described above are directed to 3GPP LTE, LTE-A and eMTC technologies, other embodiments may be applied to any other 3GPP technology, such as 5G or NR technologies, fourth generation (4G), third generation (3G) and /or IoT.

partial glossary

3GPP Third Generation Partnership Program

LTE Long Term Evolution

eMTC Enhanced Machine Type Communications

NB-IoT Narrowband Internet of Things

NPDCCH narrowband physical downlink control channel

eNB Enhanced Node B

UE user equipment

PUSCH physical uplink shared channel

DCI downlink control information

MPDCCHMTC physical downlink control channel

PRACH physical random access channel

Claims (14)

1. A device for communication, comprising: means for receiving at the user equipment an instruction from a network entity to start a random access, wherein a first repetition value is used for the instruction to start the random access; means for determining, at the user equipment, a timing for transmitting a random access preamble based on a second repetition value, the second repetition value being a physical downlink control channel Repeating values, wherein the first repeating value is a fraction of the second repeating value or equal to the second repeating value; and Means for transmitting the random access preamble from the user equipment to the network entity on a physical random access channel using the determined timing. 2. The apparatus of claim 1, wherein the second repetition value is a configured maximum repetition value. 3. The apparatus of claim 1, wherein the instruction to initiate the random access is a physical downlink control channel command. 4. The apparatus of claim 1, wherein the timing for the random access preamble is physical random access channel timing. 5. The apparatus of claim 1, wherein the physical downlink control channel is a machine type communications physical downlink control channel or a narrowband physical downlink control channel. 6. The apparatus of claim 1, wherein transmission of the preamble occurs on a starting subframe of the physical random access channel. 7. The apparatus of claim 6, wherein the starting subframe is determined based on at least one of: the second repetition value of the physical downlink control channel, and a physical random access channel The number of repetitions or the period of the starting subframe. 8. The apparatus of any one of claims 1-7, wherein the second repetition value defines a search space for the physical downlink control channel specific to the user equipment. 9. The apparatus according to any one of claims 1-6, wherein the second repetition value is indicated in a downlink control information subframe repetition number field, the downlink control information subframe repetition number field The field is included in the downlink control information format 6-1A, 6-1B or N1. 10. The apparatus according to any one of claims 1-7, wherein the user equipment is enhanced machine type communication user equipment or enhanced coverage user equipment, or narrowband Internet of Things user equipment. 11. A device for communication, comprising: means for transmitting from the network entity to the user equipment an instruction to initiate random access using the first repeated value; means for receiving at the network entity the random access preamble from the user equipment via a physical random access channel according to the timing for transmitting the random access preamble based on the second repetition value, Wherein the first repetition value is a fraction of the second repetition value or equal to the second repetition value, and the second repetition value is a repetition value of a physical downlink control channel. 12. The apparatus of claim 11, wherein the second repetition value is a configured maximum repetition value. 13. The apparatus according to any one of claims 11-12, wherein the second repetition value is indicated in a downlink control information subframe repetition number field, the downlink control information subframe repetition number field The field is included in the downlink control information format 6-1A, 6-1B or N1. 14. A communication method, comprising: receiving at the user equipment an instruction to start random access from the network entity, wherein a first repetition value is used for the instruction to start the random access; After receiving the instruction, determining at the user equipment a timing for transmitting a random access preamble based on a second repetition value, the second repetition value being a repetition value of a physical downlink control channel, wherein the first repeat value is a fraction of the second repeat value or equal to the second repeat value; and Using the determined timing, the random access preamble is transmitted from the user equipment to the network entity on a physical random access channel.