KR20170103300A - Methods for performing narrow band machine type communication, apparatuses and systems for performing the same - Google Patents

Abstract

Provided is narrowband object communication. The narrowband object communication comprises a step of allocating a DC subcarrier for narrowband object communication.

Description

A narrowband object communication method, apparatus and system for performing the narrowband object communication method,

The present invention relates to a narrowband object communication method, and an apparatus and system for performing the narrowband object communication method.

The number of object communication terminals is arranged in a very large number and lowering the price of object communication terminals such as MTC (Machine Type Communication) terminals is a key element in implementing IoT (Internet of Things).

MTC terminals can be used in various applications, require low power consumption, and are expected to communicate for infrequent small burst transmissions.

In case of MTC object communication, high-speed data communication based on LTE is possible using 1.4MHz high-speed data rate. However, when applied to sensor-based IoT application, high-speed data rate communication is unnecessary.

Therefore, a narrowband object communication technology using a low data rate suitable for sensor-based IoT applications is required.

That is, a technology for performing narrowband object communication at a low data rate of 200 kHz or less, which is lower than the 1.4 MHz high data rate of conventional MTC object communication, is required for use in sensor-based IoT applications.

According to an aspect of the present invention, there is provided a narrowband object communication method including allocating a DC subcarrier for a narrowband object communication, the NB-IoT 1 When mapping to PRB, DC subcarriers are allocated in the middle of 12 subcarriers and 1 PRB is allocated so as not to overlap with DC subcarriers.

Although the features and elements are specifically described above in combination, those skilled in the art will recognize that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented as a computer program, software, firmware, or hardware included in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks But are not limited to, optical media such as magnetic media, such as magneto-optical media, CD-ROM disks, and digital versatile disks (DVDs). A processor associated with the software may be utilized to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC or any host computer. The processor may be a digital signal processor (DSP), a microprocessor, one or more microprocessors associated with a DSP core, a controller, a microcontroller, application specific integrated circuits (ASICs) field programmable gate array (FPGA) circuits, an integrated circuit (IC), or a state machine.

According to the narrowband object communication method and the apparatus and system for performing the above-described narrowband object communication, both the uplink and the downlink use a reduced bandwidth - for example, 180 kHz - than the 1.4 Mhz bandwidth of MTC, It is possible to provide an IoT service suitable for an application.

1 shows a downlink frame structure of NB-IoT.
2 shows an uplink frame structure of NB-IoT.
3 is a conceptual diagram for explaining uplink subcarrier spacing in the NB-IoT.
4 is a conceptual diagram illustrating a DC subcarrier in an NB-IoT according to an embodiment of the present invention.
5 is a conceptual diagram illustrating PCFICH transmission in an NB-IoT according to an embodiment of the present invention.
6 is a conceptual diagram for explaining scheduling in an NB-IoT downlink according to an embodiment of the present invention.
7 is a flowchart illustrating a contention-based random access procedure.
8 is a conceptual diagram illustrating multiplexing of uplink physical channels.
FIG. 9 is a diagram exemplifying the NB-IoT uplink physical channel PRACH format.
10 is a conceptual diagram for explaining NB-IoT TDD frame transmission and reception.

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 object communication terminal includes a terminal for implementing object communication by incorporating a sensor and a communication function. For example, the object communication terminal may include a machine type communication (MTC) terminal, a Narrow band LTE terminal, a narrow band IoT terminal, and a CIoT (Cellular IoT) terminal .

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.

MTC (Machine Type Communication) is a technology applied to cellular based object communication, especially LTE based object communication. It can provide IoT service at a data rate of 1.4 MHz (6 RB) IoT service can be provided based on the network.

On the other hand, in CIoT (Cellular IoT), 1 RB is divided into 12 again to provide IoT service within GSM 200 KHz (1 RB) data rate, and low speed data rate, that is, Provides IoT service that is suitable for rate-oriented (no high-speed communication) sensor-oriented application.

For Narrow Band-IoT (NB-IoT), we use a bandwidth that is less than the 1.4Mhz bandwidth of MTC.

In the NB-IoT (Narrow Band-IoT), both the uplink and the downlink use IoT service suitable for sensor-based applications at a low data rate using a reduced bandwidth - for example, 180 kHz - than the 1.4 MHz bandwidth.

In NB-IoT, OFDMA is used for downlink, and very small subcarrier spacing can be used. In the downlink, for example, 15 kHz subcarrier spacing or 3.75 kHz subcarrier spacing may be used.

In the NB-IoT uplink, FDMA or SC-FDMA using GMSK modulation can be used. In the NB-IoT uplink, 2.5kHz subcarrier spacing can be used. In the case of downlink, interference due to CRS is always present, but there is always no interference in the uplink, so that uplink can use subcarrier spacing smaller than downlink in terms of interference.

The Narrow Band-IoT (NB-IoT) may include three different modes of operation: a stand-alone operation, a guard band operation, and an in-band operation .

In a stand-alone operation, the spectrum currently used by the GERAN system replaces one or more GSM carriers.

In the guard band operation, unused resource blocks existing in the LTE carrier guard-band are used.

In-band operation uses resource blocks in the normal LTE carrier.

In NB-IoT, a single synchronization is performed for a plurality of operation modes such as a stand-alone operation, a guard band operation, and an in-band operation. As shown in FIG.

PDSCH, M-PDSCH, and M-EPDCCH to which "M" is added to EPDCCH represent the corresponding physical channels and signals used in the NB-IoT.

NB-IoT downlink

1 shows a downlink frame structure of NB-IoT. Referring to FIG. 1, the NB-IoT downlink has a subframe duration of 1 ms, and one subframe is composed of two slots each having a length of 0.5 ms. An OFDM symbol consists of a cyclic prefix (CP) and a signal. The OFDM symbol interval, the slot interval, and the subframe interval may be set to be compatible with the existing LTE.

In case of NB-IoT downlink, the same 15kHz subcarrier spacing as LTE can be used to be compatible with existing LTE.

In the case of NB-IoT, since it is mainly used to transmit very short or very small amount of packets such as sensing data, in case of NB-IoT downlink, resource allocation or scheduling is performed using 12 subcarriers for user terminal .

For the NB-IoT downlink, downlink physical channels such as PBCH, PDSCH, and EPDSCH can be used. The PBCH can be used to broadcast important system information, the PDSCH can be used to send downlink UE data and control information, and the EPDCCH can be used to send downlink control information (e.g., scheduling information) .

In case of NB-IoT, the function of PDCCH is performed in EPDCCH, so that PDCCH of existing LTE can not be used.

Alternatively, in the case of NB-IoT, the PDCCH may be implemented to transmit only the SIB (System Information Block), and may be implemented to perform all the remaining functions of the existing PDCCH in the EPDCCH.

In case of NB-IoT, PSS and SSS can be used for cell search as a synchronization signal, and PSS and SSS can provide cell identification information. NB-IoT and existing LTE can share the same cell ID.

4 is a conceptual diagram illustrating a DC subcarrier in an NB-IoT according to an embodiment of the present invention. Referring to FIG. 4, when mapping from a 1.4 MHz 6PRB to an NB-IoT 1PRB in a conventional MTC, DC subcarriers are allocated among 12 subcarriers, and 1 PRB is allocated to the DC subcarriers so as not to overlap with DC subcarriers. ). That is, if the 1 PRB allocation position includes a DC subcarrier, the DC subcarrier does not transmit.

The PCFICH transmitted on the 6PRB in the existing LTE-based MTC downlink subframe corresponds to a narrowband-6 PRB of 180khz (6 x 30Khz), which is about 1/6 of that of the existing LTE in NB-IoT. Instead of being transmitted in a reduced size, it is included in a sub-frame of 6 ms which is increased by 6 times in the time domain,

The PCFICH carries information on the number of OFDM symbols used for allocation of the PDCCH in the subframe. Information on the number of OFDM symbols to which the PDCCH is allocated is referred to as a control format indicator (CFI). All UEs in the cell must search for a region to which the PDCCH is allocated, and thus the CFI can be set to a cell-specific value. In general, the control region to which the PDCCH is allocated is allocated to the most preceding OFDM symbols of the downlink subframe, and the PDCCH can be allocated to a maximum of three OFDM symbols.

For example, the CIF is set to 3, so that the PDCCH is allocated in the preceding three OFDM symbols in the subframe. The UE detects its PDCCH in the control domain and can detect its PDSCH through the PDCCH detected in the corresponding control domain.

When the PCFICH is transmitted in one subframe in the NB-IoT downlink, the CFI can be fixed to a specific value, thereby using the fixed OFDM symbols to which the PDCCH is allocated.

Alternatively, when the PCFICH is transmitted in one subframe in the NB-IoT downlink, the CFI can be transmitted to the MIB. In this case, the OFDM symbols to which the PDCCH is allocated can be varied.

6 is a conceptual diagram for explaining scheduling in an NB-IoT downlink according to an embodiment of the present invention. Referring to FIG. 6, when resource allocation is performed in a 1.4 MHz bandwidth in the case of the existing LTE-based MTC downlink, resources are all allocated to one symbol and resources are allocated to other symbols (610) However, in the NB-IoT downlink, resource allocation (620) is performed according to the order of the PRBs to be transmitted, so that the user terminal can perform decoding in units of 1 PRB. In the case of the existing LTE-based MTC downlink, a transmission / reception buffer is required in proportion to the number of allocated PRBs at the time of resource allocation. Since buffering is required for a maximum of 6 PRBs, latency increases in resource allocation, There is a problem. Since the NB-IoT downlink resource allocation scheme of the present invention performs resource allocation 620 in order of PRBs to be transmitted, the terminal can perform decoding in units of 1 PRB, so that the latency decreases during resource allocation and the decoding time Is also effective.

NB-IoT uplink

For the NB-IoT uplink, SC-FDMA may be used, which may allow for flexible UE bandwidth allocation including single tone transmission as a special case of SC-FDMA.

In the case of uplink SC-FDMA, the co-scheduled UEs are time-aligned so that the arrival time difference in the base station eNB is within the CP (cyclic prefix).

15kHz sub-carrier spacing may be used for the NB-IoT uplink and considering the time accuracy that can be achieved when detecting PRACH from UEs in very poor coverage conditions , The CP duration (CP duration) should be increased. To achieve this, the subcarrier spacing may be increased about 6 times as compared to the MTC. That is, 2.5kHz subcarrier spacing can be used for the NB-IoT M-PUSCH. In addition, SC-FDMA can be used in multiple tones transmission with additional PARR reduction techniques to support high data rates.

For the NB-IoT uplink, the subcarrier is tight packed to achieve high capacity while improving coverage and reducing device complexity and cost.

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).

In the time domain, a 6: 1 time stretch as well as a 4: 1 time stretch can be used, or a different time stretch value can be used and the subcarrier space is adjusted according to the time stretch value. For example, when the time stretch value is 6, the subcarrier space is 15 kHz / 6 = 2.5 kHz, and when the time stretch value is 4, the subcarrier space is 15 kHz / 4 = 3.75 kHz.

3A is a conceptual diagram for explaining uplink sub-carrier spacing in the NB-IoT. Referring to FIG. 3A, instead of reducing the conventional LTE bandwidth to -6 x 180 kHz, 6 PRB - to 1/6 the narrowband -6 PRB of 180 kHz (6 x 30 kHz), the existing 1 ms sub- The frame interval is increased by 6 times in the time domain to use a sub-frame of 6 ms (M-subframe).

That is, in the uplink subcarrier spacing in the NB-IoT, one PRB is composed of 12 subcarriers and one PRB corresponds to a bandwidth of 30 kHz, so that one subcarrier has subcarrier spacing of 2.5 kHz (30 kHz / 12) .

In case of the NB-IoT uplink, it is possible to use two uplink physical channels of M-PRACH and M-PUSCH or three uplink physical channels of M-PRACH, M-PUCCH and M-PUSCH. The function of transmitting the uplink control information of the dedicated PUCCH may be implemented by the M-PRACH and the M-PUSCH. In this case, the M-PUCCH may not be used. Due to the data package size of the IoT application, the uplink control information (ACK / NACK for M-PDSCH) can be multiplexed with the data package of the general application in the M-PUSCH.

2 shows an uplink frame structure of NB-IoT. Referring to FIG. 2, in the case of the NB-IoT uplink, an M-subframe has a subframe duration of 6ms, and one M-subframe has two slots each having a length of 3ms. In the case of the NB-IoT uplink, subcarrier spacing of 2.5 kHz can be used as described above.

RACH (Random Access Channel) is a kind of data request signal transmitted by a terminal to a base station at an arbitrary time for connection and data transmission of a base station, and serves as a start of communication starting from all terminals. It is necessary to provide a method for successfully receiving a RACH signal transmitted from a very distant mobile station and successfully transmitting a response signal to the long distance mobile station.

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

The contention-based random access procedure may be performed in four steps as shown in FIG. 7 is a flowchart illustrating a contention-based random access procedure. Referring to FIG. 7, a random access preamble is transmitted from a terminal to a base station (step 701), a base station transmits a random access response in response thereto (step 703), and a scheduled transmission from a terminal (step 705) And performing contention Resolution (step 707) at the base station. In the case of the contention-free random access, the UE reserves the random access preamble allocated by the base station. In FIG. 7, the contention resolution (step 707) is not necessary and only two steps 701 and 703 are performed.

In order to perform the LTE random access procedure due to the reduced bandwidth of the NB-IoT in the uplink design based on the SC-FDMA of the NB-IoT, a modification to the PRACH design is required. Lt; / RTI >

In the SC-FDMA based uplink design of NB-IoT, the multiplexing of uplink physical channels can be designed according to a plurality of coverage classes. The coverage class can be divided into three types, for example, basic coverage (144dB MCL), robust coverage (154dB MCL), and extreme coverage (164dB MCL).

8 is a conceptual diagram illustrating multiplexing of uplink physical channels. Referring to FIG. 8, different PRACH preamble formats may be applied to terminals having different coverage classes when multiplexing PRACH and PUSCH.

Depending on the PRACH time-frequency resource configuration, cell coverage classes may be differently applied.

Specifically, cell coverage classes can be applied differently depending on the length of the PRACH preamble. For example, PRACH preamble format 0 can be applied to basic coverage, and PRACH preamble format 1 can be applied to terminals belonging to robust coverage. PRACH preamble format 2 can be applied to terminals belonging to extreme coverage.

For the PRACH preamble formats 0 and 1, an 80 kHz bandwidth can be used. The large subcarrier spacing may cause the PRACH preamble transmission to be robust to carrier frequency offset and Doppler shift.

Different cyclic shifts can be applied depending on the cell size. At a given cell size (i.e., given a cyclic shift), the longer the PRACH preamble, the more orthogonal preambles can be. For example, in the case of the 80 kHz bandwidth for PRACH, there may be a tradeoff between PRACH subcarrier spacing and PRACH preamble length. For example, when using 312.5 kHz subcarrier spacing, the maximum PRACH preamble length may be 80 / 0.3125 = 256.

The PUSCH may be frequency multiplexed with the PRACH in PRACH slots. The PRACH time-frequency resource can be configured by the base station, and the PRACH time-frequency resource configuration (such as PRACH slot length and period) can be determined by factors such as random access load, cell size, and the like.

In particular, the NB-PRACH uplink transmission may be single-tone transmission with frequency hopping. Considering the above-described coverage class by the single-tone transmission as described above, it is possible to provide low power and low complexity of the UE, in particular, performance guarantee in an extreme coverage environment.

Alternatively, the NB-PRACH may use 3.75 kHz subcarrier spacing for the single-tone transmission, and using 3.75 kHz subcarrier spacing may result in more preamble (s) than using 15 kHz subcarrier spacing And can support extended coverage - up to 40 km of cell size - by providing improved performance in extreme coverage environments.

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

FIG. 9 is a diagram exemplifying the NB-IoT uplink physical channel PRACH format. Referring to FIG. 8, the NB-IoT uplink can be transmitted in a single tone, and PRACH can be transmitted in a single tone using 312.5 Hz subcarrier spacing, which is much smaller than 2.5kHz, which is the NB-IoT uplink subcarrier spacing have.

Since the NB-IoT uplink PRACH is transmitted in a single tone using very small 312.5 Hz subcarrier spacing over a very small narrow band, the NB-IoT PRACH transmit power can always be transmitted at maximum power. The NB-IoT PRACH maximum transmission power may use a predetermined value.

Or to implement low power operation, the NB-PRACH can transmit the NB-PRACH at (at) maximum power, except for the lowest repetition level (when the coverage grade is high), if more than one repetition level is configured in the cell Otherwise, the UE may transmit the NB-PRACH using power ramping.

NB-PRACH repeated transmission

It is possible to provide NB-PRACH repetition transmission when constructing NB-PRACH resources to support NB-IoT terminals belonging to the above-described different coverage classes. The NB-IoT terminals may select an appropriate NB-PRACH repeat transmission based on the coverage class.

NB-PRACH repeated transmission is provided for the number of times selected from the predetermined set {1, 2, 4, 8, 16, 32, 64, 128}.

The base station can set up to perform up to three kinds of NB-PRACH repeated transmissions based on the above-mentioned coverage class from the predetermined set.

The DCI (Downlink Control Information) in the NB-PDCCH can indicate the number of repetitive transmissions of the NB-IoT RAR / Retransmission of Msg3 / msg4. In this case, the NB-IoT UE repeatedly retransmits Msg3, and if it fails to receive the Msg4 continuously for a predetermined number of times, the NB-IoT UE repeatedly transmits the Msg4 after receiving the RAR, You can determine that the ratings are inconsistent and change the coverage rating. In this case, the number of Msg3 retransmissions before changing the coverage class may be indicated in the DCI (Downlink Control Information) in the NB-PDCCH.

In the object communication method according to an embodiment of the present invention, there is a dual mode that supports both MTC object communication using a bandwidth of 1.4 MHz - 6 PRB and NB-IOT object communication using a 180 kHz bandwidth .

Which of these can be supported can be sent with high layer signaling. For example, it can be included in the information of the MIB or SIB and transmitted. Also, when the NB-IoT terminal uses 1-PRB, one 1-PRB can be allocated and used within the system bandwidth of the existing LTE system.

The TDD frame configuration of the NB-IoT can be adaptively operated according to the coverage expansion level.

10 is a conceptual diagram for explaining NB-IoT TDD frame transmission and reception. Referring to FIG. 10, a guard time exists between a frame transmission interval and a frame reception interval. If the cell coverage is large, the TDD frame configuration can be set so as to increase the guard time.

In case of NB-IoT uplink single tone transmission, cyclic prefix (CP) may not be used.

The NB-IoT uplink single tone or multi tone transmission can support distributed transmission within one PRB as disclosed in FIG.

Scrambling is performed using M-subframe index instead of slot index. Here, the M-subframe means a unit of time required for transmitting all 1.4MHz 6PRBs divided by 1PRB.

Alternatively, the subframe index may be used for initialization so that the subframe index is counted from 0 to 59 instead of 0 to 9 without using the M-subframe.

Previously, there are 10 subframes within a 10 msec frame, so only counts from 0 to 9. If 6: 1 time stretch is applied, 60 msec can be a frame. In this case, counts from 0 to 59 can be implemented.

The NB-IoT PSS / SSS signal is not punctured by the LTE CRS signal or transmitted to the resource where the LTE CRS exists in order not to affect the existing LTE system. In order to avoid collision with the PDCCH, the PDCCH is not allocated to the first 3 OFDM symbols of the subframe to which the PDCCH is allocated. To minimize the complexity of PSS detection, PSS allows all base stations to transmit the same signal regardless of cell ID, unlike conventional LTE. In order to support both Extended CP and Normal CP, the time domain signal of the PSS having the length L should be arranged to be terminated at the end of the subframe, and the cyclic prefix of the PSS signal should be PSS The rear part of the entire signal is transposed in front. For example, if the time domain PSS length is 740 and the length of one OFDM symbol is FFT size 128 + CP length 9, then 740 is not an integer multiple of (128 + 9). The minimum value that is larger than 740 and becomes an integer multiple of (128 + 9) is 822, which is 82 larger than 740. In this case, the PSS signal is placed at the end of the subframe and the last 82 signals of the PSS signal are transmitted in front. Finally, to reduce the complexity of the initial synchronization process, PSS is sent by differential encoding.

In case of NB-IoT UL, Tail biting convolutional code and turbo code according to the size of data to be transmitted to the PUSCH can be selectively used. For example, in the case of an NB-IoT system that transmits very small data such as a sensor, the NB-IoT system may transmit the minimum transport block size specified in the current LTE. In this case, use tail biting convolutional code rather than turbo.

The PBCH of the NB-IoT transmits using all OFDM symbols in one or more subframes. If the OFDM symbol in the subframe is partially transmitted, the PDSCH for transmitting the SIB is filled in the remaining OFDM symbols without transmitting PDCCH or PCFICH. However, CRS resource allocation is avoided.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (1)

Allocating a DC subcarrier for narrowband object communication,
When mapping from MTC 1.4MHz 6PRB to NB-IoT 1 PRB, DC subcarriers are allocated in the middle of 12 subcarriers and 1 PRB is allocated so as not to overlap with DC subcarriers. Communication method.

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