KR20170115933A - Method for performing random access considering coverage level, subcarrier spacing and/or multi-tone transmission - Google Patents

Abstract

A random access method in a terminal for uplink data transmission in a random access procedure between a cellular-based object communication terminal and a base station is disclosed. The method includes performing a random access procedure between the object communication terminal and the base station, wherein the random access procedure includes selecting a PRACH (Physical Random Access Channel) resource considering a coverage level and multi-tone transmission support . When the object communication device or the object communication device operating in the cellular based IoT system performs random access, the terminal can perform an efficient random access procedure corresponding to the coverage level, the subcarrier spacing setting, the multi-tone setting, It is possible to reduce the operation time of the UE that occurs due to the increase of the number of repetition and the PRACH resources corresponding to the coverage level when the coverage level is changed, thereby reducing energy consumption and improving the delay time performance .

Description

[0001] The present invention relates to a method and apparatus for random access considering coverage level and subcarrier spacing setting and / or multi-

[0001] The present invention relates to a method for performing random access in an object communication terminal or an object communication device, and more particularly, to a method for performing random access in a object communication terminal or an object communication device, And a method for selecting an efficient preamble in case of failure and performing random access.

In the cellular-based IoT system for realizing the Internet environment of objects, it is necessary to provide a reliable connection based on a wide coverage in the license band for providing services of a large number of terminals, for example, a communication terminal or a communication device We are aiming.

As an example of a cellular-based IoT system, in the case of NB-IoT (Narrow Band-IoT), a reduced bandwidth than the 1.4 MHz bandwidth of MTC (Machine Type Communication), i.e., a reduced bandwidth over both the uplink and downlink, Using 180 kHz-, we provide IoT service suitable for sensor-oriented applications at low data rates.

In the NB-IoT, OFDMA is used for the downlink, and very small subcarrier spacing, for example, 15kHz subcarrier spacing, can be used.

In the NB-IoT uplink, SC-FDMA can be used. In the NB-IoT uplink, 3.75 kHz or 15kHz subcarrier spacing can be used.

The random access is a kind of data transmission procedure for the terminal to connect to the base station and transmit the data to the base station at a certain time for data transmission, and serves as a start of communication initiated at all terminals. In particular, in order to reflect the characteristics of the NB-IoT service requiring a wide coverage area, the base station can successfully receive a signal of a random access procedure transmitted from a very distant terminal with an expanded coverage of 20 dB or more, And a method for successfully transmitting to a long distance terminal is required.

In order to perform the LTE random access procedure due to the reduced bandwidth of NB-IoT in the uplink design based on SC-FDMA of NB-IoT, it is necessary to modify the PRACH (Physical Random Access Channel) It can affect some of the access procedures.

LTE random access is used for various purposes such as initial access when setting up a radio link, scheduling request, and the main purpose of random access is to achieve uplink synchronization and prepare for data transmission. Random access may be contention-based random access or contention-free random access.

In a cellular-based IoT system, for example, a Narrowband-Internet of Thing (NB-IoT) system, services are divided into a plurality of coverage classes (CC) or coverage levels . The coverage class (CC) or the coverage level (CL) is generally defined as the normal coverage (CC1 or CL1), robust coverage (CC2 or CL2), extreme coverage (CC3 or CL3) And the BS differentiates the parameters such as the location of the resource used by the UE, the number of repetition times, the Modulation and Coding Scheme (MCS) according to the coverage class (CC) or the coverage level (CL) CC) or the coverage level (CL) can receive an optimized service according to the channel state.

In addition, in the NB-IoT, the UE can define and support three configurations depending on whether the UE supports subcarrier spacing and / or multi-tone transmission used in uplink transmission . Table 1 shows the performance characteristics of each subcarrier spacing setting and / or multi-tone setting in the uplink transmission.

3.75kHz, single-tone Poor channel condition, low transmission rate, 15kHz, single-tone Channel state, intermediate rate, a terminal located within a radius of about 10 km from the cell center 15kHz, multi-tone Channel state is good, high data rate, terminal located at cell center

In the previously discussed NB-IoT system, when a random access procedure of a UE fails and a UE performs random access at a selected coverage class (CC) or coverage level (CL), RAR (Random (Contention Resolution, Message 4) which is a response to the connection request (Connection Request, Message 3) is not received, the random access procedure is re-executed and the preamble transmission is performed again from the preamble transmission . At this time, when continuous preamble retransmission occurs for a predetermined number of times or more, the UE changes its coverage level (CC) or coverage level (CL) to a low-level channel state and performs random access again to prepare for data transmission . However, the procedure of performing the random access re-execution after changing the coverage class (CC) or the coverage level (CL) is a method in which when the UE performs random access at the changed coverage class (CC) or the coverage level Since the random access procedure must be performed again from the beginning in the corresponding PRACH, there is a problem that the operation time and the delay time of the UE greatly increase.

Therefore, in the present invention, in a cell-based IoT system (for example, NB-IoT-), when a UE performs a random access, A method of using sequential preamble resources in a random access procedure considering the step-by-step performance of subcarrier spacing and / or multi-tone setting. Specifically, when the UE selects a resource for preamble transmission in the course of re-random access in the case of failure in transmission of a connection request message Message 3 for uplink data transmission in the random access procedure, the UE selects a coverage class (CC) or a coverage level Or the multi-tone setting that is provided within the coverage class (CC) or the coverage level (CL) after attempting to retransmit by changing the sub-carrier spacing and / or multi- (CC) or a coverage level (CL) when the random access procedure fails until the random access procedure fails.

In accordance with embodiments of the present invention, it is possible to provide an efficient (e.g., uplink) transmission scheme considering coverage class (CC) or coverage level (CL) and uplink subcarrier spacing and / or multi-tone settings in a cellular based IoT system, e.g. NB- And provides a random access method.

A method for random access in a terminal for uplink data transmission in a random access procedure between a cellular-based object communication terminal and a base station according to an aspect of the present invention includes the steps of performing a random access procedure between the object communication terminal and the base station Wherein the random access procedure includes selecting a physical random access channel (PRACH) resource in consideration of coverage level and multi-tone transmission support.

The step of selecting a random access resource in consideration of the coverage level and the support of multi-tone transmission includes a message (Message3) for requesting connection for uplink data transmission in the object communication terminal, If the transmission is not yet performed, the random access resource can be selected considering the selected coverage level and multi-tone transmission support.

When the message communication request message (Message3) for the uplink data transmission is not yet transmitted from the object communication terminal, the step of selecting the random access resource in consideration of the selected coverage level and the multi-tone transmission support state, If a transmission failure or a contention failure of a message (Msg3) requesting a connection for uplink data transmission occurs consecutively and the number of times of preamble transmission exceeds the maximum number of times of preamble transmission, It is possible to select random access resources using subcarrier spacing and / or multi-tone settings used within the same coverage level.

The step of selecting a random access resource in consideration of the coverage level and the support of multi-tone transmission includes a message (Message3) for requesting connection for uplink data transmission in the object communication terminal, And selecting a random access resource corresponding to the selected coverage level and corresponding to the multi-tone transmission support if transmission is not yet performed.

When the message communication request message (Message3) for the uplink data transmission is not yet transmitted from the object communication terminal, the step of selecting the random access resource in consideration of the selected coverage level and the multi-tone transmission support state, , A message requesting a connection for uplink data transmission (Message3) can not be transmitted yet, it is possible to select a random access resource using a multi-tone setting used within the same coverage level as the selected coverage level.

When the message communication request message (Message3) for the uplink data transmission is not yet transmitted from the object communication terminal, the step of selecting the random access resource in consideration of the selected coverage level and the multi-tone transmission support state, And performing a random access by changing the multi-tone setting at the same coverage level as the selected coverage level when transmission of a message (Message 3) requesting connection for uplink data transmission is not yet performed.

When the message communication request message (Message3) for the uplink data transmission is not yet transmitted from the object communication terminal, the step of selecting the random access resource in consideration of the selected coverage level and the multi-tone transmission support state, Sets a random access resource in consideration of the coverage level, subcarrier spacing, and / or multi-tone transmission support, if the message (Message3) requesting connection for uplink data transmission has not yet been transmitted, The random access resource can be selected by the object communication terminal step by step when the random access is performed.

When the message communication (Message3) requesting connection for uplink data transmission has not yet been transmitted, the object communication terminal changes the subcarrier spacing and / or multi-tone setting at the same coverage level as the selected coverage level to perform random access And performing the random access by changing the selected coverage level in the event of failure to the last stage of the subcarrier spacing and / or multi-tone setting combination provided within the selected coverage level after attempting the random access . ≪ / RTI >

The coverage level may include normal coverage, robust coverage, extreme coverage.

The random access procedure between the object communication terminal and the base station can be applied to cellular based narrowband object communication.

The object communication terminal may include a Narrowband-Internet of Thing (NB-IoT) terminal capable of accessing a radio access network using a channel bandwidth of 180 kHz.

Whether or not the multi-tone transmission is supported may be whether multi-tone Message 3 transmission is supported or not. The random access procedure may further comprise selecting the coverage level at the object communication terminal.

If the transmission of the message (Message3) requesting the connection for the uplink data transmission is not yet performed, it may be the case that the object communication terminal performs the first random access preamble transmission.

Wherein the random access procedure between the object communication terminal and the base station comprises: transmitting a random access preamble to the base station in the object communication terminal; receiving a RAR (Random Access Response) message from the base station in the object communication terminal; The method includes: transmitting a message (Message 3) requesting connection for uplink data transmission from the object communication terminal to the base station; and transmitting, to the object communication terminal, a message 3 indicating that the message 3 transmitted by the object communication terminal has been received And receiving the Contention Resolution. The random access procedure may be performed when a random access preamble to be used is not explicitly signaled from the base station.

According to another aspect of the present invention, there is provided a device communication terminal for performing a random access procedure for uplink data transmission with a base station for cellular-based object communication, comprising: a transceiver for transmitting or receiving a radio signal with a base station via an antenna; Wherein the random access procedure comprises a step of performing a random access procedure between the object communication terminal and the base station, the random access procedure comprising: And selecting a random access resource in consideration of transmission support.

According to another aspect of the present invention, there is provided a device for performing a random access procedure for uplink data transmission to a base station for cellular-based object communication, the device comprising: a transceiver for transmitting or receiving a radio signal with a base station via an antenna; And a processor for controlling a transceiver to determine when to transmit the wireless signal, the processor performing a random access procedure between the object communication device and the base station, the random access procedure comprising: And selecting a random access resource in consideration of whether or not to support tone transmission.

According to another aspect of the present invention, there is provided a random access method between a cellular-based object communication terminal and a base station, the method including: receiving a random access preamble from the object communication terminal in the base station; Receiving a message (Message 3) requesting a connection for uplink data transmission from the object communication terminal in the base station, and transmitting the message (Message 3) from the base station to the object communication terminal And transmitting a Contention Resolution (CR) indicating that a Message 3 has been received to the base station, wherein the random access procedure selects a random access resource considering a coverage level and multi-tone transmission support.

According to another aspect of the present invention, a base station for performing a random access procedure for uplink data transmission with a cellular-based object communication terminal includes a transceiver for transmitting or receiving a radio signal with the object communication terminal through an antenna, A random access preamble is transmitted from the object communication terminal, and a Random Access Response (RAR) message is transmitted to the object communication terminal Receiving a message (Message 3) requesting connection for uplink data transmission from the object communication terminal, receiving a message (Message 3) requesting connection from the object communication terminal to the object communication terminal, And a step of transmitting a contention resolution (Contention Resolution) 'S coverage level process and a multi-access resource is randomly selected in consideration of whether or not the tone transfer support.

In the present invention, in response to a coverage class or a coverage level and a subcarrier spacing setting and / or a multi-tone setting, when the object communication device or the object communication device operating in the cellular based IoT system performs random access, To the user.

In the object communication device or the object communication device, when the connection request message Message 3 for performing uplink data transmission in the random access procedure is not yet transmitted, the coverage class (CC) or the subcarrier spacing setting and / By selecting the PRACH resource and the preamble in consideration of whether or not to support the tone transmission, it is possible to further subdivide the coverage class (CC) or the coverage level introduced to support a wide coverage service so that the object communication device or the object communication device To be transmitted. It is also possible to minimize the change of coverage class (CC) or coverage level and to wait for the increase of repetition frequency and the PRACH resource corresponding to the coverage class (CC) or coverage level when changing the coverage class (CC) It is possible to reduce the operation time of the terminal, reduce the energy consumption, and improve the delay time performance.

The object communication terminal or the object communication device through the method of performing random access for uplink data transmission in the object communication device or the object communication device operating in the cellular based IoT system of the present invention is capable of performing subcarrier spacing and / / RTI > and / or < / RTI > multi-tone configuration, thereby minimizing coverage class or coverage level changes, thereby reducing the operating time of the object communication device or the object communication device And the increase of the delay time can be mitigated to improve the energy consumption and the delay time performance.

It is possible to efficiently utilize the subcarrier spacing and / or multi-tone transmission setting of the object communication device or the object communication device to simplify the random access performance for the uplink data retransmission, thereby improving the delay time and energy consumption Can be reduced.

1 is a conceptual diagram illustrating a configuration of a PRACH resource in a time-frequency domain in a conventional LTE environment.
FIG. 2 is a conceptual diagram for explaining uplink single-tone transmission when 3.75 kHz subcarrier spacing is used in NB-IoT (Narrow Band-Internet of Thing).
FIG. 3 is a conceptual diagram for explaining uplink single-tone transmission or multi-tone transmission when 15kHz subcarrier spacing is used in NB-IoT (Narrow Band-Internet of Thing).
4 is a conceptual diagram illustrating a PRACH resource configuration including a single-tone preamble and a multi-tone preamble.
FIG. 5 is a flowchart for explaining a random access procedure between an object communication terminal and a base station in a cellular-based narrowband object communication according to an embodiment of the present invention.
6 is a flowchart for explaining Message 3 collision by the same preamble selection of a UE during a random access operation.
FIG. 7 is a flowchart for explaining an operation in the case where Message 3 transmission is not yet performed in FIG.
FIG. 8 is a conceptual diagram illustrating the current state and order of PRACH resources according to BS environment and coverage level according to an embodiment of the present invention.
FIG. 9 is a diagram showing an example of a PRACH preamble resource configuration according to the coverage level in FIG.
10 is a flowchart illustrating a method of performing random access for uplink data transmission considering a coverage level.
11 is a flowchart illustrating a method of performing random access for uplink data transmission in a mobile station considering a coverage level and subcarrier spacing and / or multi-tone settings according to an embodiment of the present invention.
FIG. 12 is a flowchart illustrating a method of performing random access for uplink data transmission in a terminal considering a coverage level and subcarrier spacing and / or multi-tone settings according to another embodiment of the present invention.
13 is a conceptual diagram illustrating an example of resource allocation for performing random access for uplink data transmission in a UE considering a coverage level and a subcarrier spacing setting according to another embodiment of the present invention.
FIG. 14 is a conceptual diagram illustrating an example of resource allocation for performing random access for uplink data transmission in a terminal considering a coverage level and multi-tone setting according to another embodiment of the present invention.
15 is a schematic block diagram of an NB-IoT terminal according to an embodiment of the present invention.
16 is a schematic block diagram of an NB-IoT communication system according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

The terminal may be a mobile station (MS), a user equipment (UE), a user terminal (UT), a wireless terminal, an access terminal (AT), a terminal, a fixed or mobile subscriber unit, A cellular phone, a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU), a mobile node, a mobile, a mobile station, a personal digital assistant ), A smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a consumer electronics (CE) or other terminology.

Various embodiments of the terminal may be used in various applications such as cellular telephones, smart phones with wireless communication capabilities, personal digital assistants (PDAs) with wireless communication capabilities, wireless modems, portable computers with wireless communication capabilities, Device, a wearable device having a wireless communication function, a gaming device having a wireless communication function, a music storage and playback appliance having a wireless communication function, an Internet appliance capable of wireless Internet access and browsing, as well as a combination of such functions But are not limited to, portable units or terminals. A base station generally refers to a fixed point in communication with a terminal and includes a base station, a Node-B, an eNode-B, an advanced base station (ABS) But is not limited to, an HR-BS, a site controller, a base transceiver system (BTS), an access point (AP), or any other type of interfacing device capable of operating in a wireless environment.

The base station may be a RAN that may also include other base stations and / or network elements (not shown) such as a base station controller (BSC), a radio network controller (RNC), relay nodes, It can be a part. The base station may be configured to transmit and / or receive wireless signals within a particular geographic area, which may be referred to as a cell (not shown).

A cell may also be divided into cell sectors. For example, a cell associated with a base station may be divided into three sectors. Thus, in one embodiment, the base station may include three transceivers, one transceiver for each sector of the cell. In another embodiment, the base station may utilize multiple-input multiple output (MIMO) techniques and therefore utilize multiple transceivers for each sector of the cell.

The following terminal includes a sensor communication terminal and an object communication terminal for implementing object communication. For example, the object communication terminal may include an MTC (Machine Type Communication) terminal or a NB-IoT (Narrowband Internet of Thing) terminal.

The NB-IoT (Narrowband-IoT) terminal is a terminal capable of accessing the radio access network of the 180-kHz channel bandwidth of NB-IoT, a cellular narrowband technology for realizing a low-power IoT network providing extended coverage in the licensed band. The narrow bandwidth can be operated in the in-band, which uses a part of resources in the existing LTE network, a guard-band that utilizes the protection frequency band, and a stand-alone mode that uses a part of the GSM band.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

In case of NB-IoT, 1 PRB is divided into 12 subcarriers in order to support IoT service within the 200kHz band of existing GSM. Instead of reducing the existing bandwidth by 6 times, the time domain is increased by 6 times (6: 1 time stretch) can be used. In the case of NB-IoT, it may have multiple coverage levels or coverage classes, which may include, for example, basic coverage (144 dB MCL), robust coverage , 154dB MCL), and extreme coverage (164dB MCL).

The NB-PRACH uplink transmission can be performed in frequency hopping with a single-tone transmission that can guarantee performance in an extreme coverage environment and can provide low power and low complexity of the UE.

The NB-PRACH uses 3.75 kHz subcarrier spacing for the single-tone transmission, which provides improved performance in more preamble and extreme coverage environments than 15 kHz, .

In addition, the NB-PRACH may be provided with two CP (Cyclic Prefix) lengths to support different cell sizes.

NB-PRACH repetition transmission is a method of constructing NB-PRACH resources to support NB-IoT terminals belonging to different coverage classes. The UEs can operate by selecting the NB-PRACH with the appropriate repetitive transmission according to the coverage class.

The NB-PRACH repetition transmission may be provided a predetermined number of times in a predetermined set {1, 2, 4, 8, 16, 32, 64, 128}, and the eNB may allocate the predetermined set It is possible to perform up to three kinds of repetitive NB-PRACH transmissions.

In the power ramping of the NB-PRACH, if more than one repetition level is configured in the cell, the UE transmits at the maximum power in the NB-PRACH except for the lowest repetition level with the highest coverage level. Otherwise, Can be used to transmit NB-PRACH to achieve low-power operation.

The NB-IoT terminal may fail to receive the Msg4 after receiving the RAR and transmitting the Msg3 in the random access procedure. At this time, if the MS repeatedly retransmits Msg3 and fails to receive consecutive Msg4 for a predetermined number of times, the MS determines that the coverage class is inconsistent and changes the coverage class. The number of retransmissions until the coverage class is changed can be indicated in the DCI (Downlink Control Information) in the NB-PDCCH.

Hereinafter, NPRACH is used with the same meaning as NB-PRACH.

3.75 kHz, 15 kHz subcarrier spacing in NB-IoT can be used for uplink (UL) transmission.

With respect to the UL grant, the UL subcarrier spacing may have 3.75 kHz or 15 kHz, and 3.75 kHz or 15 kHz may be displayed as 1-bit information, and the UL grant may be used in the UL grant in the RAR message. That is, it can be indicated by using 1 bit in the UL grant (uplink allocation) in the RAR message transmitted by the base station to determine which subcarrier spacing to use in 3.75 kHz or 15 kHz in NB-IoT.

In NB-IoT, two subcarrier spacing of 3.75 kHz or 15 kHz can be specifically used in a random access procedure through a RAR message.

The frequency location in the subcarrier offset with respect to the NB-PRACH subcarrier locations may have seven values, for example, 0, 12, 24, 36, 2, 18, , And 3 bits.

The number of subcarriers may have, for example, four values of 12, 24, 36 and 48, and may be represented by 2 bits.

The NB-PRACH repetition can be accomplished using contiguous subframes within one period. Specifically, the NB-PRACH repetitions may be transmitted back-to-back in successive subframes within one period for the NB-PRACH.

The frequency location in subcarrier offsets associated with NB-PRACH subcarrier locations may vary depending on the number of subcarriers (e.g., 12, 24, 36, 48). Specifically, a frequency location in a subcarrier offset may be 0, 12, 24, 36, 2, 18 (for example, 12, 24, 36, 48) according to the number of subcarriers , And 34, and the number of subcarriers and the frequency position within the subcarrier offset can be defined and used in a predetermined table.

With respect to the NB-PRACH, the adjustment of the uplink transmission timing is performed for at least a predetermined time (e.g., 12 ms) after the end of the corresponding timing advance command transmission, -PUSCH Can be applied from the beginning of transmission. Here, the timing advance command can be included in the RAR and transmitted.

With respect to the NB-PRACH configuration in the NB-IoT, up to three NB-PRACH resource configurations can be configured in one cell.

Practically, PRACH resources can be divided and used for single-tone, multi-tone transmission. In particular, the PRACH subcarrier can be divided and used for single-tone, multi-tone transmission in the PRACH configuration according to the coverage level shown in FIG.

When a UE performs an RACH procedure for Msg3 transmission over a single-tone or multi-tone, it can use divided subcarrier resources to be used in the PRACH according to a single-tone transmission or a multi-tone transmission. Specifically, a subcarrier for a single-tone transmission can be guaranteed (can not be 0) in a specific PRACH resource. For example, the ratio of the number of subcarriers to be used for the single tone MSG3 transmission can not be zero in at least one resource other than at least 32, 64, 128 NB-PRACH repetition times. Or the ratio of the number of subcarriers to be used for the single tone MSG3 transmission can not be 0 at least in a resource having NB-PRACH repetition times of 32, 64, and 128. [

Multitone MSG3 transmission may not be supported when the number of NB-PRACH repetitions is 32, 64, 128.

The range of subcarrier resources used for multi-tone transmission can be represented using 2 bits. For example, a starting subcarrier index reserved for a UE supporting multi-tone Msg3 transmission may be represented by, for example, 2 bits ({0, 1/3, 2/3, 1 } x N_sc ^ NB-PRACH). Here, N_sc ^ NB-PRACH denotes the total number of subcarriers, and 1/3 x N_sc ^ NB-PRACH denotes 1/3 of total subcarriers.

It is also possible to use subcarriers for single-tone Msg 3 transmission in the absence of subcarrier resources for multi-tone Msg3 transmission. If the UE selects a reserved resource for a single tone MSG3 message, the MSG3 message may be assigned a singleton. This means that if all the PRACH resources do not have a reserved subcarrier range to be used by the UE supporting the multi-tone MSG3 transmission, then the UE should use the reserved NB-PRACH resources for the single tone MSG3 transmission.

In the NB-PRACH resource, other subcarriers (subcarriers other than subcarriers to be used for multi-tone transmission) may be utilized as a range for single tone MSG3 transmission.

The Msg3 message subcarrier allocation may be the same as the UL grant allocation on the NB-PDCCH.

The Msg3 repetition number may be the same as the NB-PUSCH repetition number.

From the technical point of view, the 3.75 kHz, 15 kHz subcarrier spacing can operate robustly even in poor channel conditions due to the relatively good PSD (Power Spectral Density) performance of 3.75 kHz subcarrier spacing, In the case of subcarrier spacing, the uplink data rate of the UE can be improved through a relatively wide bandwidth, but it is required to use the subcarrier spacing in a good channel condition. Therefore, performance improvement can be expected by providing two subcarrier spacing of 3.75 kHz and 15 kHz according to the channel state of the UE. The multi-tone transmission has the effect of using multiple subcarriers to improve the transmission rate compared to the single-tone transmission.

The following formula used in RAN1 can be reused for power ramping in NB-PRACH. However, it is possible to add the (-10 * log10 (numRepetitionPerPreambleAttempt) term and to correct the repetitive transmission effect through the added term.

-REAMBLE_RECEIVED_TARGET_POWER is defined as preambleInitialReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_TRANSMISSION_COUNTER - 1) * powerRampingStep - 10 * log10 (numRepetitionPerPreambleAttempt), where DELTA_PREAMBLE is zero.

With respect to colliding transmissions, for standalone operations and guard band operations, the NB-IoT channels and signals, except for the NB-PBCH, are "LTE CRS (Cell REs (Resource Elements) corresponding to " -specific reference signals ". There is no NB-IoT signaling of LTE CSI-RS (Channel State Information - Reference Signals) or PRS (Positioning Reference Signals). NB-PDCCH and NB-PDSCH can be rate-matched around LTE cell-specific reference signals (CRS) for in-band operation.

With respect to the scheduling collision, the NB-IoT UE that has received the grant from the NB-PDCCH receives the grant from the corresponding NB-PDSCH or NB-PUSCH transmission start and the end of the NB- During the time interval it is not necessary to additionally monitor any DL grant or NB-PDCCH for UL grant.

With respect to collision handling for NB-IoT, UEs in lower coverage are not allowed to collide with NB-PRACH opportunities collisions with higher coverage level (s) ) Can be treated as one. UEs may use only valid NB-PRACH opportunities for Msg1 transmission.

In the LTE (Long Term Evolution), a UE may start a random access procedure when a link establishment or a re-establishment is required with respect to a base station eNB (eNodeB) for data transmission. The random access may operate in a contention-free manner or a contention-based manner depending on the purpose.

In a non-contention-based random access procedure, it is used only for a special purpose such as handover. In general, a UE sets up a connection with an eNB through a contention-based random access and transmits data.

1 is a conceptual diagram illustrating a configuration of a PRACH resource in a time-frequency domain in a conventional LTE environment.

Referring to FIG. 1, a random access resource comprises a continuous time-frequency random access resource 12 called a random access (SLA) slot, and the UE transmits a preamble in an RA slot You can start the request.

A resource to which a preamble is transmitted is called a Physical Random Access Channel (PRACH) and is allocated to a certain portion of a Physical Uplink Shared Channel (PUSCH) channel. As shown in FIG. 1, the PRACH resource in the frequency domain has a bandwidth corresponding to six resource blocks (RBs).

Each cell provides 64 preambles, some of which are reserved to support non-contention-based random access, and the remaining preamble resources are again divided into resources of Group A and Group B. Group A is used to transmit a small packet, and Group B is used to transmit a large packet. In addition, the random access parameters such as the periodicity of the RA slot, the number of preambles used in the contention-based random access, and the maximum allowable message size in the group A are transmitted to the UE through the SIB 2 (System Information Block 2) message.

In the case of NB-IoT (Narrow Band-Internet of Thing) uplink and random access transmission, a reduced 180 kHz band can be allocated and used. A single-tone transmission using a single subcarrier, And multi-tone transmission to be used.

FIG. 2 is a conceptual diagram for explaining uplink single-tone transmission when 3.75 kHz subcarrier spacing is used in an NB-IoT (Narrow Band-Internet of Thing) 1 is a conceptual diagram for explaining an uplink single-tone transmission or a multi-tone transmission when 15 kHz subcarrier spacing is used in the Internet of Thing.

For a single-tone transmission, a single-tone transmission 20 using 3.75 kHz subcarrier spacing as in FIG. 2 or a single-tone transmission 30 using 15 kHz subcarrier spacing as in FIG. 3 is possible. In single-tone transmission, the data rate is low due to the use of a narrow frequency band. However, since the power is concentrated in the frequency band, the coverage efficiency is high even in a poor channel condition and the device cost and device complexity are reduced .

For multi-tone transmission, the terminal is capable of multi-tone transmission 35 using 15 kHz subcarrier spacing as in Fig. Multi-tone transmission guarantees a high data rate by using a plurality of subcarriers. However, since a relatively wide bandwidth is used, the channel condition must be good, the device cost due to increased signal processing may increase, and the device complexity may increase .

4 is a conceptual diagram illustrating a PRACH resource configuration including a preamble for performing a single-tone and multi-tone Msg3 transmission in an NB-IoT system.

-1)으로 넘버링된 싱글-톤 프리엠블(40) 및 (

), …, (

-1)으로 넘버링된 멀티-톤 프리엠블(50)으로 구성될 수 있다. Referring to FIG. 4, a PRACH resource includes 0, 1, ... , (

-1) and a single-tone preamble 40

), ... , (

-1) numbered multi-tone preamble 50.

In addition, the PRACH resource may be defined by the following parameters transmitted from the BS to the MS.

: NPRACH 자원 주기(resource periodicity)

: NPRACH resource periodicity

: 할당된 NPRACH 의 첫 번째 subcarrier의 주파수 위치 (frequency location of the first sub-carrier allocated to NPRACH)

: The frequency location of the first subcarrier of the allocated NPRACH (the first subcarrier allocated to the NPRACH)

: NPRACH에 할당된 서브캐리어 개수(number of sub-carriers allocated to NPRACH)

: Number of sub-carriers allocated to NPRACH (number of sub-carriers allocated to NPRACH)

: 각 시도별 NPRACH 반복 개수(number of NPRACH repetition per attempt)

: Number of NPRACH repetition per attempt for each trial

: NPRACH 시작 시간(starting time)

: NPRACH start time

: 멀티-톤 msg3 전송을 지원하는 UE를 위해 예약된 NPRACH 서브캐리어의 범위의 시작 서브캐리어 인덱스를 계산하기 위한 비율 값(fraction for calculating starting subcarrier index for the range of NPRACH subcarriers reserved for indication of UE support for multi-tone msg3 transmission)

: A ratio value for calculating a starting subcarrier index of a range of NPRACH subcarriers reserved for a UE supporting multi-tone msg3 transmission (fraction for generating subcarrier index for the UE support for multi-tone msg3 transmission)

Hereinafter, a competition-based random access procedure will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is a flowchart for explaining a random access procedure between an object communication terminal and a base station in a cellular based narrowband object communication according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating a random access procedure for selecting a same preamble ≪ / RTI > FIG.

1. Message 1 transmission [Preamble transmission]

Referring to FIG. 5, the NB-IoT terminal starts a random access and transmits a preamble to a base station (step 501). At this time, the UE randomly selects one preamble in the resource corresponding to the coverage level and transmits it to the base station. The different preambles transmitted to the base station by the orthogonality between the preambles can be received by the base station.

6, even if two or more UEs 550 (UE2 560) transmit the same preamble at the same time, the BS can receive the preamble (steps 601 and 603) . However, when two or more UEs select the same preamble, a collision may occur in the subsequent Message 3 transmission process of the UE.

2. Message 2 transmission [Random Access Response transmission]

For the successfully received preamble request, the base station transmits a RAR (Random Access Response) message including resource information for TA (Timing Alignment) and Message 3 transmission, for example, a PUSCH (Physical Uplink Shared Channel) Shared Channel) (Step 503). The UE can determine whether the preamble received by the UE itself has been successfully received by receiving the RAR message. If it is determined that the preamble transmission has failed, the UE performs preamble transmission for re-performing the random access procedure in the new RA slot after the random backoff time. If the preamble transmission fails more than a predetermined number of times, the UE informs the upper layer of the problem of the random access procedure.

3. Message 3 [Send Connection Request]

After receiving RAR (Random Access Response), the UE transmits Message3, which is a Connection Request, from the reserved resource in the PUSCH (Physical Uplink Shared Channel) (505). Message 3 transmission is performed by the HARQ scheme. Referring to FIG. 6, when a plurality of mobile stations transmit the same preamble (steps 601 and 603) and transmit a random access response (RAR) (steps 605 and 607) A message 3 is transmitted from the same PUSCH resource (steps 611 and 613), and a collision occurs.

Here, Message 3 (Msg3) is a message for the MS to make a connection request to the BS for uplink data transmission. After receiving the response message Contention Resolution from the base station after transmitting Message3, the UE can perform uplink transmission in the allocated resources.

When the UE transmits the preamble for the first time, it is determined that Msg3 has not yet been transmitted (added), and the preamble is selected and transmitted from the PRACH resource corresponding to the determined coverage level. Or if the UE performs the preamble transmission for the second time or more due to the Msg3 transmission failure, it is determined to be in the Msg3 retransmission process, and the random access is attempted by randomly selecting the preamble again from the resource selected as the first preamble. When the number of preamble transmissions exceeds the maximum number of preamble transmissions, the coverage level is changed, and the number of preamble transmissions is initialized to 1 again.

4. Message 4 [Contention Resolution Transfer]

The base station receiving the message 3 of the MS responds with a contention resolution (CR) in the Physical Uplink Shared Channel (PDSCH) to approve the connection request to the MS (step 507). In FIG. 6, a message 3 collision of two terminals is shown (step 611 or 613). In this case, a contention resolution (CR) is not received from the base station, and the UE performs a new preamble transmission in a new RA slot after a random backoff time. If the preamble transmission fails for a predetermined number of times or more, the terminal determines that the network can not be used.

FIG. 7 is a flowchart for explaining a random access operation in the case where Message 3 transmission is not yet performed in FIG.

Referring to FIG. 7, the object communication terminal determines whether Message 3 (Msg3) has not yet been transmitted in the random access procedure (step 710). At this time, the state in which the Msg3 transmission is not yet performed means the case where the first preamble transmission is performed.

If it is determined that the message 3 (Msg3) is not yet transmitted, the PRACH resource is selected considering the coverage level and multi-tone transmission support (step 720). Alternatively, if it is determined that the message 3 (Msg3) is not yet transmitted, the PRACH resource can be selected considering the coverage level, subcarrier spacing, and / or multi-tone transmission support. Specifically, when the message 3 (Msg3) is not yet transmitted, it means a case where a random access process is started and the first preamble transmission is performed. The PRACH resource Can be selected. Specifically, when the message 3 (Msg3) is not yet transmitted, the object communication terminal initializes the preamble transmission number exceeding the maximum number of preamble transmission times, and if the first preamble transmission is performed under different conditions or when the maximum number of preamble transmission times is not exceeded The first random access preamble transmission is performed.

8 is a conceptual diagram illustrating a PRACH resource usage status according to a BS environment and a coverage level according to an embodiment of the present invention.

The present invention provides a method of performing random access considering a Coverage Level (CL) and subcarrier spacing and / or multi-tone settings in a cellular-based IoT system, for example, an NB-IoT system.

8, in an embodiment of the present invention, the base station 880 provides three coverage levels (CL), and the PRACH resources utilized by each coverage level (CL) are divided into subcarrier spacing and / or multi- Configure the resources so that they can be used according to the setting. However, this is only one embodiment of the resource configuration in the present invention depending on the performance characteristics of subcarrier spacing and / or multi-tone setting, and combinations of specific settings may be omitted or added. In the present invention, an example of the invention will be described in a direction that can maximize the sequential performance according to subcarrier spacing and / or multi-tone setting.

Referring to FIG. 8 and Table 1, a UE may be configured to select one of 15) 1) 15kHz, multi-tone, 2) 15kHz, a single- Tone, 3) 3.75 kHz, single-tone subcarriers, and / or a combination of three tones.

,

등 에 따라 범위가 결정될 수 있으며, 해당 정보는 기존과 마찬가지로 PRACH 자원을 구성하는 정보를 나타내는 메시지에 포함되어 기지국으로부터 단말로 전달 될 수 있다. CL1은 가장 좋은 채널상태를 가지므로 위 3가지 모두의 서브캐리어 및/또는 멀티-톤 설정을 사용하며, CC2는 상대적으로 좋은 채널상태를 가지므로 2) 15kHz, 싱글-톤(single-tone), 3) 3.75kHz, 싱글-톤(single-tone)의 2가지 서브캐리어 및/또는 멀티-톤 설정을 사용하며, CC3는 극한의 채널 상태를 가지므로 3.75kHz, 싱글-톤(single-tone)의 1가지 서브캐리어 및/또는 멀티-톤 설정만을 사용하는 것으로 가정한다.In response to this, the base station can also divide the preamble resources according to the set values specifically supported for each coverage level. At this time, the preamble resource has a ratio value

,

Etc., and the information may be included in a message indicating information constituting the PRACH resource and transmitted from the BS to the MS as in the conventional case. Since CL1 has the best channel state, it uses all three subcarrier and / or multi-tone settings, and CC2 has a relatively good channel state. 2) 15kHz, single-tone, 3) uses 3.75 kHz, single-tone, two subcarrier and / or multi-tone settings, and CC3 has an extreme channel state, so 3.75 kHz, single-tone It is assumed that only one subcarrier and / or multi-tone setting is used.

,

비율값을 사용하여 분할하였으며, CL 2의 프리엠블 자원을 각각 (15kHz, 싱글-톤), (3.75kHz, 싱글-톤) 자원으로 분할하기 위해

비율값을 사용하였다.In one embodiment of FIG. 8, to divide the preamble resources of CL 1 into resources (15 kHz, multi-tone), (15 kHz, single-tone) and (3.75 kHz, single-

,

To divide the preamble resources of CL 2 into (15 kHz, single-tone), (3.75 kHz, single-tone) resources, respectively

Ratio values were used.

The terminal performs synchronization with the base station for uplink data transmission and receives system information from the base station in a synchronized state with the base station. In this process, the terminal receives CL, subcarrier spacing and / or multi- Determine the setting. Then, in order to perform random access in the corresponding CL, the UE receives the PRACH resource information from the base station. In the random access procedure, the UE selects a preamble in consideration of the selected CL, subcarrier spacing, and / or multi-tone setting, and transmits the preamble to the base station. After receiving RAR (Random Access Response) from the base station, the UE receives resource information for Msg3 transmission requesting connection for uplink transmission. If the RAR is not received, the UE performs preamble transmission again, and selects and transmits a preamble in the same PRACH resource as the first selected setting. When the maximum number of preamble retransmissions is exceeded, after changing the coverage level, a preamble is selected from a PRACH resource corresponding to a possible subcarrier spacing and / or multi-tone setting within the coverage level, and then transmitted.

The Msg3 transmission performs HARQ transmission in a resource allocated by the UE. If the HARQ transmission fails due to a change in the channel state or if the MS does not receive the Msg4 even after the Msg3 transmission, the MS performs the preamble transmission again , The preamble is selected and transmitted in the same PRACH resource as the first selected setting. When the maximum number of preamble retransmissions is exceeded, a preamble is selected in the corresponding PRACH resource after changing the coverage level, subcarrier spacing and / or multi-tone setting, and then transmitted.

In all cases, if there is no selectable subcarrier spacing and / or multi-tone setting for the corresponding CL, then a CL supporting a lower channel state is selected and the corresponding subcarrier and / or multi-tone setting And selects a preamble resource to be transmitted in the corresponding PRACH resource.

FIG. 10 is a flowchart illustrating a method of performing random access of a UE for uplink data transmission considering an existing coverage level. FIG. 11 is a flowchart illustrating a method of performing random access in a UE according to an exemplary embodiment of the present invention, FIG. 2 is a conceptual diagram illustrating a method of performing a random access of a UE for uplink data transmission.

Referring to FIG. 10, in a method of performing random access in a terminal considering an existing coverage level, a terminal selects a coverage level and selects and transmits a corresponding preamble resource. Then, if the RAR is received from the base station and the Msg3 is transmitted in the HARQ manner, the random access procedure can be completed by receiving the Contention Resolution as a response from the base station. At this time, if the RAR is not received or the Msg3 HARQ transmission failure or the Contention Resolution not received occurs, the UE performs the preamble transmission process again in the same PRACH resource to retry the random access. If the number of times of preamble transmission exceeds the maximum number of preamble transmission times determined by the base station, the UE determines that the selected coverage level is not suitable for the current channel condition, changes the coverage level to a level that supports the lower channel condition And then performs a random access procedure by selecting a preamble again from the PRACH resource.

However, the procedure for performing random access re-execution after changing the coverage level (CL) includes a process for waiting for a PRACH (Physical RACH) resource for performing random access at a changed coverage level (CL) The operation time and the delay time of the terminal greatly increase because the process has to be performed again from the beginning.

Hereinafter, a method of performing random access of a terminal considering a coverage level and subcarrier spacing and / or multi-tone setting according to an embodiment of the present invention will be described.

In the case of the contention-based random access procedure, the random access preamble is explicitly signaled from the base station (the random access preamble resource to be used is explicitly indicated).

In the case of the contention-based random access procedure, the random access preamble is not explicitly signaled from the base station (the random access preamble resource to be used is not explicitly indicated).

Hereinafter, the random access procedure of FIGS. 11 and 12 can be performed when a random access preamble to be used is not explicitly signaled from the base station.

Referring to FIG. 11, according to a method for performing random access in a terminal for uplink data transmission according to an embodiment of the present invention, in a RACH process, a mobile station receives an RAR (Random Access Response) And receives resource information (step 1101).

In the allocated uplink resources, the UE transmits a message (Msg3) requesting connection for uplink data transmission to the BS (step 1103), and the UE checks whether the Msg3 transmission fails due to a change in the channel state or the like (Step 1105). If the Msg3 transmission fails, it is checked that the uplink transmission is successful (step 1107).

If the Msg3 transmission fails, the UE determines whether the Msg3 transmission failure count is less than the maximum retransmission count (step 1109). Here, the maximum number of retransmissions may be included in the DCI (Downlink Control Information).

If the Msg3 transmission failure count is smaller than the maximum retransmission count, the process returns to step 1101 to perform the RACH procedure again to receive RAR (Random Access Response), receive uplink resource information from the BS, and retry the Msg3 transmission .

If the Msg3 transmission failure count is not smaller than the maximum retransmission count, the UE may perform a sub-operation with a lower transmission rate within the same coverage level (CL) according to an embodiment of the present invention, instead of changing the existing coverage level Carrier spacing and / or multi-tone setting, performs the RACH process again, and retries the data (Msg 3) transmission process again. At this time, in the previous RACH process, the UE considers the subcarrier spacing and / or the multi-tone configuration change according to the embodiment of the present invention and immediately retransmits the RACH using the PRACH resource information preliminarily allocated to RAR (Random Access Response) (Option 2), or perform a RACH process on a PRACH resource (or a preamble resource) using subcarrier spacing and / or multi-tones with a lower transmission rate within the same coverage level (CL) 1) to attempt Msg 3 transmission. If the UE experiences a continuous transmission failure in the current subcarrier spacing and / or multi-tone configuration, the UE changes its coverage level to another coverage level and receives PRACH resource information corresponding to the corresponding coverage level (CL) .

Hereinafter, a random access method for performing uplink data transmission according to exemplary embodiments of the present invention will be described.

Assuming that a particular UE performing random access according to an embodiment of the present invention is located in the CL2 region, the UE selects a preamble resource with a 15kHz single-tone setting of the initial CL2 And receives RAR (Random Access Response) as a response to the preamble transmission from the base station.

The RAR that is a response to the preamble transmission from the base station is not received and may attempt to transmit the preamble again. If the RAR is not received continuously and the number of times of preamble transmission exceeds the number of times of preamble transmission, And 3.75 kHz, which has the maximum transmission rate, and selects a preamble in the corresponding PRACH resource to perform the random access procedure again.

If the Msg 3 transmission fails more than the maximum number of preamble transmissions in the random access procedure, then the UE changes the existing coverage level CL in accordance with an embodiment of the present invention, A 3.75 kHz single-tone sub-carrier spacing and / or multi-tone setting is selected, and the RACH process is performed again to retry the Msg 3 transmission process. At this time, in the previous RACH process, the UE immediately retransmits the PRACH resource information preliminarily allocated to the RAR (Random Access Response) considering the subcarrier spacing and / or multi-tone setting change according to an embodiment of the present invention (Option 2), and attempt to transmit data (Msg 3) by performing the RACH process again (Option 1) in the PRACH resource for 3.75 kHz single-tone transmission of CL2. If the UE fails to transmit Msg3 consecutively more than the maximum number of preamble transmissions in the random access process even in the 3.75 kHz single-tone setting, the UE changes the coverage level to CL3 and transmits the PRACH corresponding to the corresponding coverage level (CL) After receiving the resource information, the RACH process is performed.

FIG. 12 is a flowchart illustrating a method of performing random access for uplink data transmission in a terminal considering a coverage level and subcarrier spacing and / or multi-tone settings according to another embodiment of the present invention.

Referring to FIG. 12, according to another embodiment of the present invention, in order to perform a random access procedure for a UE, a UE selects a coverage level (step 1201) The resource is selected and transmitted (step 1203). Then, uplink resources for Msg3 transmission are acquired together with the RAR which is a response from the base station. The MS can perform Msg3 transmission in the HARQ scheme. If the Msg3 is received in the BS, the MS can finally receive the Contention Resolution message from the BS to complete the random access procedure.

A failure of the random access procedure may occur because the UE does not receive the RAR, fails to transmit the Msg3, or fails to receive the contention resolution. In each case, the UE retries transmission of the preamble again to perform the random access procedure.

If the RAR is not received, that is, if the preamble transmission fails, random access is re-executed and it is determined whether the number of times of preamble transmission exceeds the maximum number of preamble transmissions (step 12130). If the number of times of transmission of the maximum preamble is exceeded, It immediately changes to a coverage level that supports the channel state (step 1201). This is because the random access preamble transmission is performed using the 3.75 kHz, single-tone setting, so that the UE can know that the random access preamble can not be transmitted even at the lowest setting at the coverage level.

The MS attempts to transmit Msg3 using the HARQ scheme (step 1207), determines whether the transmission is successful in the HARQ scheme of Msg3 (step 1209), and determines whether Contention Resolution is received if the Msg3 transmission of the HARQ scheme is successful 12110).

If it is determined that the Msg3 transmission failure (Msg3 transmission failure to the HARQ scheme) or the Contention Resolution reception failure, the UE determines that the number of times of preamble transmission exceeds the maximum number of times of preamble transmission in the random access re- The random access procedure may be re-performed (steps 1217, 1219, 1203, 1201) through a method utilizing sub-carrier spacing and / or multi-tone settings in accordance with embodiments of the invention. Specifically, the terminal determines whether there is a subcarrier spacing and / or multi-tone setting of a lower rate that is changeable within the current coverage level (step 1217), and if so, (Step 1219), and selects and transmits a preamble in the corresponding PRACH resource (step 1203) to re-execute the random access procedure. At this time, the UE restarts the random access procedure from the preamble transmission (Option 1) according to the embodiments of the present invention, or the base station changes the subcarrier spacing and / or multi-tone setting change It is possible to directly perform HARQ scheme transmission (Option 2) of Msg3 by using the uplink resource information allocated in advance to the RAR. If a continuous Msg3 transmission failure or a Contention Resolution reception failure occurs even in the setting of the lowest transmission rate that can be selected within the coverage level of the UE, the UE changes the coverage level to a lower level, Performs random access on the resource.

Hereinafter, a random access method for performing uplink data transmission according to another embodiment of the present invention will be described.

Assuming that a particular UE performing a random access procedure for uplink data transmission according to an embodiment of the present invention is located in the CL2 region, the UE may use a single-tone (15 kHz) Preamble resource is selected and transmitted by setting. The RAR that is a response to the preamble transmission from the base station is not received and can attempt to transmit the preamble again. If the number of times of preamble transmission exceeds the maximum number of times of preamble transmission due to the continuous occurrence of RAR not received, A 3.75 kHz, single-tone setting with a maximum transmission rate of CL3 supporting the channel state can be selected, and a random access procedure can be performed again by selecting a preamble in the corresponding PRACH resource.

If consecutive Msg3 transmission fails after the RAR (Random Access Response) is received, or if the Contention Resolution receiving process fails, a random access can be performed by selecting a preamble in the same PRACH resource as the first selected setting. If the number of times of preamble transmission exceeds the maximum number of preamble transmissions, the UE may perform an operation to change the coverage level CL in the same coverage level CL2 Selects a subcarrier spacing with a low transmission rate and / or a multi-tone setting of 3.75 kHz, a single-tone, selects a preamble in a corresponding PRACH resource, and performs a random access procedure again. At this time, in the previous random access procedure, the UE considers the subcarrier spacing and / or the multi-tone setting change according to an embodiment of the present invention and directly transmits uplink resource information allocated to the RAR (Random Access Response) (Option 2), and perform a random access procedure again (Option 1) in the PRACH resource for 3.75 kHz, single-tone transmission of CL2. If the UE fails to transmit Msg3 continuously or does not receive Contention Resolution even in 3.75 kHz single-tone configuration, the UE changes the coverage level to CL3 and waits for the PRACH resource corresponding to the corresponding coverage level (CL) And then performs a random access procedure.

Assuming that a specific terminal to be subjected to the random access method for uplink data transmission is located outside the CL1 area according to another embodiment of the present invention, the terminal sets the initial CL1 to 15 kHz, multi-tone setting The random access procedure is started by selecting a preamble resource.

At this time, if the number of times of preamble transmission exceeds the maximum number of times of preamble transmission due to a failure of random access due to continuous RAR non-reception, the UE changes its CL2 to a coverage level supporting a lower channel state, , And selects a single-tone setting of 15 kHz to support random access with the corresponding PRACH resource (preamble resource).

Alternatively, if the number of times of preamble transmission due to Msg3 HARQ transmission failure or Contention Resolution failure after the RAR reception exceeds the maximum number of preamble transmission times, the mobile station changes the existing coverage level (CL) A PRACH resource (or preamble resource) using a sub-carrier spacing and / or a multi-tone setting of 15 kHz, single-tone setting with a lower transmission rate within the same coverage level CL is selected Random access can be retried again. At this time, in the previous random access procedure, the UE determines, based on the subcarrier spacing and / or multi-tone configuration change according to another embodiment of the present invention, PRACH resource information preliminarily allocated to RAR (Random Access Response) Message 3 retransmission may be performed immediately (Option 2), or the random access procedure may be performed again (Option 1) in the PRACH resource for 15 kHz single-tone transmission of CL1 as described above. If the terminal experiences a continuous Msg3 transmission failure or no contention resolution even in a 15kHz single-tone configuration, change it to a 3.75kHz single-tone configuration and retry with Option 1 or Option 2 I can do it. If the message 3 transmission fails even in the 3.75 kHz single-tone setting, the terminal determines that all the settings provided by the CL 1 can not be communicated, changes to CL 2, and then transmits the 15 kHz single- -tone), it is possible to re-execute the random access process or the Message 3 transmission process.

That is, when the Msg3 transmission failure during the random access procedure or the number of times of preamble transmission due to the absence of Contention Resolution exceeds the maximum number of preamble transmission times, the UE generates a random access with a subcarrier spacing and / If the last step of the subcarrier spacing and / or multi-tone setting to provide and re-perform is failed, the current coverage level may be changed finally and the random access procedure for uplink data transmission may be performed step by step. However, if the number of times of preamble transmission due to random access failure due to RAR non-reception exceeds the maximum number of times of preamble transmission, the UE may change the coverage level to a level that supports the channel state that is one level lower and perform the random access procedure again .

Referring to FIG. 8, when random access is performed in the UE for uplink data transmission according to an embodiment of the present invention, sub-carrier spacing and / or multi- - An example of selecting a PRACH resource (or a preamble resource) sequentially in the direction of the arrow so that it has step performance according to tone setting.

Assuming that a specific terminal performing random access of a terminal for uplink data transmission is located outside the CL1 area according to another embodiment of the present invention, A random access procedure can be performed.

13, if a terminal performs random access by selecting a 15-kHz, single-tone setting of the initial CL1 and consecutive Msg3 transmission fails or Contention Resolution not received, the same coverage level CL1 In the single-tone setting of 15 kHz, 3.75 kHz, the single-tone setting, and then the random access procedure is attempted. After that, if the random access fails, the coverage level can be changed to CL2 and then a random access can be attempted with a single-tone setting of 15 kHz using a single-tone setting and again with a random access failure of 3.75 kHz. If the random access fails again, the last coverage level can be changed to CL3 and random access can be attempted with a 3.75kHz, single-tone setting. At this time, if the random access fails, the UE performs a random access and the number of preamble retransmissions exceeds the maximum number of transmissions due to Msg3 HARQ transmission failure or contention resolution message incompletion, .

Assuming that a particular terminal performing random access of the terminal for uplink data transmission is located outside the CL1 area according to another embodiment of the present invention, the terminal uses the multi- Level to perform a random access procedure.

14, when a terminal performs a random access by selecting a 15-kHz multi-tone setting of the initial CL1 and then consecutively fails to transmit Msg3 or does not receive a contention resolution, the same coverage level In the CL1's 15kHz, multi-tone setting, it tries to change the subcarrier setting to the 15kHz, single-tone setting. After that, if the random access fails, the coverage level may be changed to CL2 and then a 15kHz, multi-tone setting may be used, and if the random access fails again, a random access may be attempted with a single tone setting of 15kHz. Finally, if the random access fails again, random access can be attempted with CL3's 3.75kHz, single-tone setting. At this time, if the random access fails, the UE performs a random access and the number of preamble retransmissions exceeds the maximum number of transmissions due to Msg3 HARQ transmission failure or contention resolution message incompletion, .

FIG. 15 is a schematic block diagram of an NB-IoT terminal according to an embodiment of the present invention, and FIG. 16 is a schematic block diagram of an NB-IoT communication system according to an embodiment of the present invention.

15 and 16, the NB-IoT terminal 100 includes a transceiver 120, a processor 110, and an antenna 130. The NB-IoT terminal 100 includes a base station 120 and the above- , A random access method considering a coverage level for uplink data transmission and subcarrier spacing and / or multi-tone setting.

The transceiver 120 transmits or receives a radio frequency signal to or from a base station 120 through an antenna 130 and transmits data or data to the base station 120 through a downlink 152 from a base station 120 through an antenna 130. [ And a control signal, and transmits data and control signals to the base station 120 through an uplink (154).

The processor 110 may control the transceiver 100 to determine when to transmit the control signal. The processor 110 performs a random access procedure according to embodiments of the present invention, a random access method considering a subcarrier spacing and / or multi-tone setting for uplink data transmission.

The object communication terminal, for example, the NB-IoT terminal, the MTC (Machine Type Communication) terminal, and the terminal in the enhanced coverage, includes: a transceiver for transmitting or receiving a radio signal with a base station via an antenna; And a processor for determining when to transmit the data. The processor processes the step of performing a random access procedure between the object communication terminal and the base station, and the random access procedure selects a physical random access channel (PRACH) resource considering a coverage level and multi-tone transmission support Step < / RTI > Specifically, the random access procedure may include selecting a physical random access channel (PRACH) resource considering a coverage level, subcarrier spacing, and / or multi-tone transmission support.

The object communication device may include a transceiver for transmitting or receiving a radio signal with a base station via an antenna, and a processor for controlling the transceiver to determine when to transmit the radio signal. The processor processes the random access procedure between the object communication device and the base station, and the random access procedure selects a PRACH (Physical Random Access Channel) resource considering a coverage level and multi-tone transmission support Step < / RTI > Specifically, the random access procedure may include selecting a physical random access channel (PRACH) resource considering a coverage level, subcarrier spacing, and / or multi-tone transmission support.

The processor 110 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a microprocessor, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, specific integrated circuits (ASICs), field programmable gate array (FPGA) circuits, integrated circuits (IC), state machines, and the like. The processor 110 may perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the terminal to operate in a wireless environment. The processor 110 may be coupled to the transceiver 120.

Although processor 110 and transceiver 120 are shown as separate components in Fig. 14, processor 110 and transceiver 120 may be integrated together in an electronic package or chip.

For example, in one embodiment, the antenna 130 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the antenna 130 may be a radiator / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the antenna 130 may be configured to transmit and receive both RF and optical signals. The antenna 130 may be configured to transmit and / or receive any combination of wireless signals. The transceiver 120 may be configured to modulate the signals to be transmitted by the antenna 130 and to demodulate the signals received by the antenna 130.

A base station that performs a random access procedure for uplink data transmission with a cellular-based object communication terminal is composed of a transceiver, a processor, and an antenna. The base station includes a NB-IoT terminal and a random access procedure according to embodiments of the present invention, It is possible to perform a random access method considering a coverage level for uplink data transmission and subcarrier spacing and / or multi-tone setting.

A base station for performing a random access procedure for uplink data transmission with a cellular-based object communication terminal includes a transceiver for transmitting or receiving a radio signal with the object communication terminal through an antenna, And a processor that determines the processor. The method comprising: receiving a random access preamble from the object communication terminal; transmitting a random access response (RAR) message to the object communication terminal; requesting a connection for uplink data transmission from the object communication terminal (Contention Resolution) indicating that the Message 3 transmitted by the object communication terminal has been received to the object communication terminal is transmitted to the object communication terminal, The access procedure may be implemented to configure Physical Random Access Channel (PRACH) resources in consideration of the coverage level and the multi-tone setting. In particular, the random access procedure may be implemented to configure Physical Random Access Channel (PRACH) resources in consideration of the coverage level, subcarrier spacing, and / or multi-tone setting.

A base station may communicate with one or more (e.g., one or more) stations via an air interface, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet And can communicate with the terminal.

The NB-IoT communication system may be a multiple access system and may employ channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, a base station and an NB-IoT terminal of a RAN may be a Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA) system capable of establishing an air interface using a wideband CDMA (WCDMA) Can be implemented. WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA +). The HSPA may include High Speed Downlink Packet Access (HSDPA) and / or High Speed Uplink Packet Access (HSUPA). In another embodiment, the base station and the MTC terminals may use Evolved UTRA (Evolved UTRA), which may establish a public interface using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A). E-UTRA). ≪ / RTI >

In other embodiments, the base station and the NB-IoT terminal may be configured to use IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access), CDMA2000, CDMA2000 1X, CDMA 2000 Evolution-Data Optimized (EV- (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution Such as Enhanced Data Rates for GSM Evolution (EDGE), GSM / EDGE RAN (GERAN), and the like.

The base station of FIG. 16 may be, for example, a wireless router, HNB, HeNB, or AP and may utilize any suitable RAT that facilitates wireless connection in a localized area, such as a location in a business, home, vehicle, campus, . In one embodiment, the base station and NB-IoT terminals may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station and terminals may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In another embodiment, base station and NB-IoT terminals may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to set up a picocell or femtocell. The base station can directly access the Internet. Thus, the base station may not be required to access the Internet through the core network.

Claims (26)

A random access method in a terminal for uplink data transmission in a random access procedure between a cellular-based object communication terminal and a base station,
And performing a random access procedure between the object communication terminal and the base station,
Selecting a random access resource in consideration of coverage level and multi-tone transmission support. 2. The method of claim 1, wherein selecting a random access resource based on the coverage level and multi-tone transmission support
And selecting a random access resource considering the selected coverage level and multi-tone transmission support, if the message communication (Message3) requesting connection for uplink data transmission has not yet been transmitted from the object communication terminal Based random access method between a cellular-based object communication terminal and a base station. 3. The method as claimed in claim 2, wherein, when the message communication (Message3) requesting connection for uplink data transmission has not yet been transmitted, the object communication terminal selects a random access resource considering the selected coverage level and multi- The step
When the HARQ transmission failure or contention resolution of the message (Msg3) requesting connection for uplink data transmission is consecutively generated in the object communication terminal and the number of preamble transmission exceeds the preamble maximum transmission number Selecting a random access resource using different subcarrier spacing and / or multi-tone settings to be used within the same coverage level as the selected coverage level. 2. The method of claim 1, wherein selecting a random access resource based on the coverage level and multi-tone transmission support
Selecting a random access resource corresponding to the selected coverage level and corresponding to the selected multi-tone transmission support if a message (Message3) requesting connection for uplink data transmission is not yet transmitted from the object communication terminal Wherein the random access method is a random access method between a cellular-based object communication terminal and a base station. 5. The method of claim 4, wherein if the message (Message3) requesting connection for uplink data transmission is not yet transmitted from the object communication terminal, the random access resource is selected considering the selected coverage level and multi-tone transmission support The step
Selecting a random access resource using a multi-tone setting to be used within a coverage level equal to a selected coverage level when transmission of a message (Message3) requesting connection for uplink data transmission is not yet performed in the object communication terminal A method for random access between a cellular terminal and a base station. 5. The method of claim 4, wherein if the message (Message3) requesting connection for uplink data transmission is not yet transmitted from the object communication terminal, the random access resource is selected considering the selected coverage level and multi-tone transmission support The step
And performing a random access by changing the multi-tone setting at the same coverage level as the selected coverage level when transmission of a message (Message3) requesting connection for uplink data transmission is not yet performed in the object communication terminal A method for random access between a cellular terminal and a base station. 7. The method of claim 6, further comprising: if the message communication request message (Message3) is not yet transmitted for uplink data transmission, the random access resource is selected in consideration of the selected coverage level and multi-tone transmission support The step
The base station sets up a random access resource in consideration of the coverage level, subcarrier spacing, and / or multi-tone setting, and the terminal transmits a message (Message3) requesting connection for uplink data transmission from the object communication terminal, Wherein when the random access is not yet performed, the object communication terminal selects the random access resource step by step upon performing the random access. 5. The method of claim 4, wherein if the message (Message3) requesting connection for uplink data transmission is not yet transmitted from the object communication terminal, subcarrier spacing and / or multi-tone setting is performed at the same coverage level as the selected coverage level The step of changing and performing the random access
And performing the random access by changing the selected coverage level when the last step of the subcarrier spacing and / or multi-tone setting combination provided within the selected coverage level fails after attempting the random access Wherein the random access method is a random access method between a cellular-based object communication terminal and a base station. 2. The method of claim 1, wherein the coverage level comprises normal coverage, robust coverage, and extreme coverage. 2. The method of claim 1, wherein the random access procedure between the object communication terminal and the base station is applied to cellular based narrowband object communication. 2. The method of claim 1, wherein the object communication terminal comprises a Narrowband-Internet of Thing (NB-IoT) terminal capable of accessing a radio access network using a channel bandwidth of 180 kHz. Access method. The method of claim 1, wherein the multi-tone transmission support is a multi-tone Message 3 transmission support. The method of claim 1, wherein the random access procedure comprises:
Further comprising selecting the coverage level at the object communication terminal. ≪ RTI ID = 0.0 > 11. < / RTI > 2. The method of claim 1, further comprising: transmitting a message (Message3) If the transmission has not yet been completed, the object communication terminal initializes the number of times of preamble transmission exceeding the maximum number of times of transmission of the preamble and then transmits the first random access preamble without exceeding the maximum number of times of transmission of the maximum preamble, Based object communication terminal and the base station. The method of claim 1, wherein the random access procedure between the object communication terminal and the base station
Transmitting a random access preamble from the object communication terminal to a base station;
Receiving a RAR (Random Access Response) message from the base station in the object communication terminal;
Transmitting a message (Message 3) requesting a connection for uplink data transmission from the object communication terminal to the base station; And
Receiving a contention resolution indicating that Message 3 transmitted from the object communication terminal is received at the base station from the object communication terminal
Based object communication terminal and a base station. The random access method according to claim 1, wherein the random access procedure is performed when a random access preamble to be used is not explicitly signaled from the base station. A object communication terminal for performing a random access procedure for uplink data transmission with a base station for cellular-based object communication, the object communication terminal comprising:
A transceiver for transmitting or receiving a radio signal with a base station via an antenna;
And a processor for controlling the transceiver to determine when to transmit the radio signal, wherein the processor
The method comprising: performing a random access procedure between the object communication terminal and the base station,
Selecting a random access resource in consideration of a coverage level and whether multi-tone transmission is supported; and performing random access with a base station for cellular-based object communication. A object communication device for performing a random access procedure for uplink data transmission with a base station for cellular-based object communication, the object communication device comprising:
A transceiver for transmitting or receiving a radio signal with a base station via an antenna;
And a processor for controlling the transceiver to determine when to transmit the radio signal, wherein the processor
The method comprising: performing a random access procedure between the object communication device and the base station,
Selecting a random access resource in consideration of a coverage level and multi-tone transmission support; and performing random access with a base station for cellular-based object communication. A random access method between a cellular-based object communication terminal and a base station,
Receiving a random access preamble from the object communication terminal at the base station;
Transmitting a Random Access Response (RAR) message to the object communication terminal;
Receiving, from the base station, a message (Message 3) requesting connection for uplink data transmission from the object communication terminal; And
And transmitting, by the base station, a contention resolution (CR) indicating that the message 3 transmitted from the object communication terminal to the object communication terminal has been received by the object communication terminal, the random access process including a coverage level and a multi- Wherein the random access resource is selected in consideration of whether or not the mobile terminal supports the random access resource. 20. The method of claim 19, wherein configuring Random Access resources in consideration of the coverage level and multi-tone transmission support
A message (Message3) requesting connection for uplink data transmission from the object communication terminal, Wherein the random access resource corresponding to the selected coverage level and corresponding to the multi-tone transmission support is selected when transmission is not yet performed. 21. The method of claim 20, wherein the multi-tone transmission support is a multi-tone Message 3 transmission support. 21. The method of claim 20,
Further comprising selecting the coverage level at the object communication terminal. ≪ RTI ID = 0.0 > 11. < / RTI > 1. A base station for performing a random access procedure for uplink data transmission with a cellular-based object communication terminal,
A transceiver for transmitting or receiving a radio signal with the object communication terminal through an antenna;
And a processor for controlling the transceiver to determine when to transmit the radio signal, wherein the processor
Receiving a random access preamble from the object communication terminal;
Transmitting a Random Access Response (RAR) message to the object communication terminal;
Receiving a message (Message 3) requesting connection for uplink data transmission from the object communication terminal; And
The method comprising the steps of: transmitting, to the object communication terminal, a contention resolution indicating that Message 3 transmitted by the object communication terminal has been received to the base station,
Wherein a random access resource is selected in consideration of a coverage level and whether multi-tone transmission is supported, and a base station performing a random access procedure for uplink data transmission with a cellular based object communication terminal. 24. The method of claim 23, wherein selecting a random access resource in consideration of the coverage level and multi-tone transmission support
A message (Message3) requesting connection for uplink data transmission from the object communication terminal, And a random access resource corresponding to the selected coverage level and corresponding to the multi-tone transmission support is selected when the transmission is not yet performed, and a random access resource corresponding to the selected coverage level is selected, . 24. The base station as claimed in claim 23, wherein whether the multi-tone transmission is supported is whether the multi-tone Message 3 transmission is supported or not. 24. The base station as claimed in claim 23, wherein the coverage level is selected by the object communication terminal, and the base station performs a random access procedure for uplink data transmission.

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