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WO2019031889A1 - Procédé de réalisation d'un processus d'accès aléatoire et appareil associé - Google Patents

Procédé de réalisation d'un processus d'accès aléatoire et appareil associé Download PDF

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Publication number
WO2019031889A1
WO2019031889A1 PCT/KR2018/009127 KR2018009127W WO2019031889A1 WO 2019031889 A1 WO2019031889 A1 WO 2019031889A1 KR 2018009127 W KR2018009127 W KR 2018009127W WO 2019031889 A1 WO2019031889 A1 WO 2019031889A1
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WIPO (PCT)
Prior art keywords
preamble
nprach
preamble format
random access
frequency
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PCT/KR2018/009127
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English (en)
Korean (ko)
Inventor
김재형
박창환
안준기
신석민
양석철
황승계
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LG Electronics Inc
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LG Electronics Inc
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Priority to KR1020207005134A priority Critical patent/KR20200029580A/ko
Priority to US16/637,645 priority patent/US11166322B2/en
Priority to EP18843479.9A priority patent/EP3668250A4/fr
Publication of WO2019031889A1 publication Critical patent/WO2019031889A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA

Definitions

  • the present invention relates to a wireless communication system, and more particularly, to a method and an apparatus for performing a random access procedure for improving an effective range.
  • Massive Machine Type Communications which provides various services by connecting many devices and objects, is one of the major issues to be considered in next generation communication.
  • a communication system design considering a service / terminal (UE) sensitive to reliability and latency is being discussed.
  • UE service / terminal
  • NR new RAT
  • a method for a UE to perform a random access procedure in a wireless communication system supporting a first preamble format and a second preamble format comprising: receiving a Narrowband Physical Random Access Channel (NPRACH) ; And transmitting a random access preamble based on a preamble format indicated by the NPRACH configuration information from among the first preamble format and the second preamble format, wherein one symbol length of the second preamble format corresponds to the first
  • the first preamble format may have a frequency grid spacing of 3.75 kHz and the second preamble format may have a frequency grid spacing of 1.25 kHz.
  • a terminal performing a random access procedure in a wireless communication system supporting a first preamble format and a second preamble format
  • the terminal comprising: a radio frequency transceiver; And a processor operatively connected to the RF transceiver, wherein the processor controls the RF transceiver to receive Narrowband Physical Random Access Channel (NPRACH) configuration information, and wherein the first preamble format and the second
  • NPRACH Narrowband Physical Random Access Channel
  • the first preamble format is configured to transmit a random access preamble based on a preamble format indicated by the NPRACH configuration information in a preamble format
  • one symbol length of the second preamble format corresponds to three times a symbol length of the first preamble format
  • the first preamble format may have a frequency grid spacing of 3.75 kHz and the second preamble format may have a frequency grid spacing of 1.25 kHz.
  • the resource configuration for the first preamble format and the resource configuration for the second preamble format may be frequency division multiplexed (FDM) in the frequency domain.
  • FDM frequency division multiplexed
  • the starting frequency position in the resource configuration for the second preamble format may be set by adding or subtracting a frequency offset from a frequency grid selectable from the resource configuration for the first preamble format to the starting frequency position.
  • said frequency offset is set equal to a minimum hopping distance for said second preamble format, said minimum hopping distance being 1.25 kHz.
  • said frequency offset can be set to cell specific.
  • the frequency offset may be set identically for terminals having the same time resources in the resource configuration for the second preamble format.
  • the frequency grid interval selectable as the starting frequency position in the resource configuration for the second preamble format may be set to a value smaller than a frequency grid interval selectable from the resource configuration for the first preamble format to the starting frequency position .
  • a RAPID (Random Access Preamble ID) for the second preamble format may be divided according to a start frequency in a resource configuration for the second preamble format.
  • the preamble boundary according to the second preamble format is set to be aligned with the preamble boundary repeated 2 ⁇ n according to the first preamble format in the time domain, n is a positive integer, and ⁇ denotes a power .
  • a random access procedure can be efficiently performed in a wireless communication system supporting both a legacy preamble and an enhanced preamble.
  • NPRACH resource configuration can be efficiently performed in a wireless communication system supporting both a legacy preamble and an enhanced preamble.
  • Figure 1 illustrates the structure of a radio frame that may be used in the present invention.
  • Figure 2 illustrates a resource grid for downlink slots that may be used in the present invention.
  • FIG. 3 illustrates a structure of a downlink subframe that can be used in the present invention.
  • FIG. 4 illustrates a structure of an uplink sub-frame that can be used in the present invention.
  • FIG. 6 illustrates an NPRACH preamble transmission method.
  • FIG. 7 illustrates an uplink-downlink timing relation.
  • FIG. 8 illustrates an enhanced preamble in accordance with the present invention.
  • Figure 11 illustrates a flowchart of a method of performing a random access procedure in accordance with the present invention.
  • FIG. 12 illustrates a base station and a terminal to which the present invention can be applied.
  • CDMA Code Division Multiple Access
  • FDMA Frequency Division Multiple Access
  • TDMA Time Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • UTRAN Universal Terrestrial Radio Access Network
  • TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE).
  • GSM Global System for Mobile communications
  • GPRS General Packet Radio Service
  • EDGE Enhanced Data Rates for GSM Evolution
  • OFDMA may be implemented with wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Evolved UTRAN (E-UTRAN).
  • the UTRAN is part of the Universal Mobile Telecommunications System (UMTS).
  • the 3GPP (3rd Generation Partnership Project) LTE system is a part of E-UMTS (Evolved UMTS) using E-UTRAN and 3GPP LTE-A (Advanced) system is an evolved version of 3GPP LTE,
  • the Pro system is an evolved version of 3GPP LTE-A.
  • the 3GPP LTE / LTE-A / LTE-A pro is mainly described, but the technical principle of the present invention is not limited thereto.
  • the specific terms used in the following description are provided to facilitate understanding of the present invention, and the use of such specific terms may be changed into other forms without departing from the technical principles of the present invention.
  • the present invention can be applied not only to a system according to the 3GPP LTE / LTE-A / LTE-A professional standard, but also to a system according to another 3GPP standard, IEEE 802.xx standard or 3GPP2 standard, RAT). ≪ / RTI >
  • a user equipment includes various devices that can be fixed or mobile and communicate with a base station (BS) to transmit and receive data and / or control information.
  • the UE may be a terminal, an MS, a mobile terminal, a UT, a subscriber station, a wireless device, a PDA (Personal Digital Assistant), a wireless modem , A handheld device, and the like.
  • the UE may be mixed with the UE.
  • a base station is generally a fixed station that communicates with a UE and / or another BS, and communicates with the UE and other BSs to exchange various data and control information.
  • the base station BS includes an Advanced Base Station (ABS), a Node-B (NB), an evolved NodeB (eNB), a next Generation NodeB, a Base Transceiver System (BTS), an Access Point Server, node, TP (Transmission Point), and the like.
  • the base station BS may be intermixed with an eNB or a gNB.
  • a terminal receives information from a base station through a downlink (DL) and transmits information to a base station through an uplink (UL).
  • the information transmitted and received between the base station and the terminal includes general data information and various control information, and there are various physical channels depending on the type / use of the information transmitted / received.
  • a mobile station When the power is turned off, the power is turned on again, or a terminal that newly enters a cell performs an initial cell search operation such as synchronizing with a base station.
  • a mobile station receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from a base station, synchronizes with the base station, and acquires information such as a cell identity.
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • the terminal can acquire system information broadcasted in the cell through the physical broadcast channel (PBCH) from the base station.
  • PBCH physical broadcast channel
  • the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.
  • DL RS downlink reference signal
  • the UE Upon completion of the initial cell search, the UE receives a physical downlink control channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH) according to physical downlink control channel information to obtain more specific system information Can be obtained.
  • a physical downlink control channel (PDCCH)
  • a Physical Downlink Shared Channel (PDSCH)
  • the terminal may perform a random access procedure to complete the connection to the base station.
  • the UE transmits a preamble through a Physical Random Access Channel (PRACH), receives a response message for a preamble through a physical downlink control channel and a corresponding physical downlink shared channel .
  • PRACH Physical Random Access Channel
  • a contention resolution procedure such as transmission of an additional physical random access channel and reception of a physical downlink control channel and corresponding physical downlink shared channel can be performed .
  • the MS having performed the procedure described above transmits a physical downlink control channel / physical downlink shared channel reception and a Physical Uplink Shared Channel (PUSCH) / physical uplink as a general uplink / downlink signal transmission procedure.
  • a physical uplink control channel (PUCCH) transmission can be performed.
  • the control information transmitted from the UE to the Node B is collectively referred to as Uplink Control Information (UCI).
  • UCI Uplink Control Information
  • the UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and Request Acknowledgment / Negative ACK), SR (Scheduling Request), CSI (Channel State Information)
  • the CSI includes a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indication (RI), and the like.
  • the UCI is generally transmitted through the PUCCH, but may be transmitted via the PUSCH when the control information and the traffic data are to be simultaneously transmitted. In addition, UCI can be transmitted non-periodically through the PUSCH according to the request / instruction of the network.
  • Figure 1 illustrates the structure of a radio frame that may be used in the present invention.
  • OFDM Orthogonal Frequency Division Multiplexing
  • SF subframe
  • a subframe is defined as a predetermined time interval including a plurality of OFDM symbols .
  • the LTE (-A) system supports a Type 1 radio frame structure applicable to Frequency Division Duplex (FDD) and a Type 2 radio frame structure applicable to TDD (Time Division Duplex).
  • FDD Frequency Division Duplex
  • TDD Time Division Duplex
  • Figure 1 illustrates the structure of a Type 1 radio frame.
  • a downlink radio frame is composed of 10 subframes, and one subframe is composed of two slots in a time domain.
  • the time taken for one subframe to be transmitted is called a transmission time interval (TTI).
  • TTI may refer to the time it takes for one slot to be transmitted.
  • the length of one subframe may be 1 ms and the length of one slot may be 0.5 ms.
  • One slot includes a plurality of OFDM symbols in a time domain and a plurality of resource blocks (RBs) in a frequency domain.
  • RBs resource blocks
  • an OFDM symbol represents one symbol interval.
  • An OFDM symbol may also be referred to as an SC-FDMA symbol or a symbol interval.
  • a resource block (RB) as a resource allocation unit may include a plurality of consecutive subcarriers in one slot.
  • the number of OFDM symbols included in one slot may vary according to the configuration of a cyclic prefix (CP).
  • CP cyclic prefix
  • a CP has an extended CP and a normal CP.
  • the number of OFDM symbols included in one slot may be seven.
  • the OFDM symbol is configured by the extended CP, since the length of one OFDM symbol is increased, the number of OFDM symbols included in one slot is smaller than that of the normal CP.
  • the number of OFDM symbols included in one slot may be six. If the channel state is unstable, such as when the UE moves at a high speed, an extended CP may be used to further reduce inter-symbol interference.
  • the Type 2 radio frame is composed of two half frames, each half frame is composed of five subframes and includes a downlink interval (e.g., DwPTS (Downlink Pilot Time Slot)), a guard interval (GP , And an uplink interval (e.g., uplink pilot time slot (UpPTS)).
  • a downlink interval e.g., DwPTS (Downlink Pilot Time Slot)
  • GP guard interval
  • UpPTS uplink interval
  • One subframe consists of two slots.
  • the downlink interval e.g., DwPTS
  • the uplink interval e.g., UpPTS
  • UpPTS uplink pilot time slot
  • a SRS Sounding Reference Signal
  • PRACH Random access preamble Physical Random Access Channel
  • the guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.
  • the structure of the radio frame described above is merely an example, and the number of subframes included in a radio frame, the number of slots included in a subframe, and the number of symbols included in a slot can be variously changed.
  • Figure 2 illustrates a resource grid for downlink slots that may be used in the present invention.
  • the downlink slot includes a plurality of OFDM symbols in the time domain.
  • one downlink slot includes seven OFDM symbols, and one resource block (RB) is illustrated as including 12 subcarriers in the frequency domain.
  • Each element on the resource grid is referred to as a Resource Element (RE).
  • One RB includes 12 x 7 REs.
  • the number N DL of RBs included in the downlink slot depends on the downlink transmission band.
  • the structure of the uplink slot may be the same as the structure of the downlink slot.
  • the resource grid of the slot described above is merely an example, and the number of symbols, resource elements, and RBs included in the slot may be variously changed.
  • FIG. 3 illustrates a structure of a downlink subframe that can be used in the present invention.
  • a maximum of 3 (or 4) OFDM symbols located in front of a first slot in a subframe corresponds to a control region for control channel allocation.
  • the remaining OFDM symbols correspond to a data area to which PDSCH (Physical Downlink Shared Channel) is allocated, and the basic resource unit of the data area is RB.
  • PDSCH Physical Downlink Shared Channel
  • Examples of the downlink control channel used in the LTE (-A) system include a Physical Control Format Indicator Channel (PCFICH), a Physical Downlink Control Channel (PDCCH), and a Physical Hybrid ARQ Indicator Channel (PHICH).
  • PCFICH Physical Control Format Indicator Channel
  • PDCCH Physical Downlink Control Channel
  • PHICH Physical Hybrid ARQ Indicator Channel
  • the PCFICH carries information about the number of OFDM symbols transmitted in the first OFDM symbol of the subframe and used for transmission of the control channel in the subframe.
  • the PCFICH is composed of four Resource Element Groups (REG), and each REG is evenly distributed in the control area based on the cell ID.
  • REG Resource Element Group
  • One REG can be composed of four resource elements.
  • the PCFICH indicates a value of 1 to 3 (or 2 to 4) and is modulated by Quadrature Phase Shift Keying (QPSK).
  • QPSK Quadrature Phase Shift Keying
  • the PHICH carries an HARQ ACK / NACK signal in response to the uplink transmission.
  • the PHICH is allocated on the remaining REG except CRS and PCFICH (first OFDM symbol) in one or more OFDM symbols set by the PHICH duration.
  • the PHICH is allocated to three REGs that are distributed as much as possible on the frequency domain. PHICH will be described in more detail below.
  • n OFDM symbols hereinafter referred to as a control region
  • n is an integer of 1 or more and is indicated by the PCFICH.
  • the control information transmitted through the PDCCH is called DCI (Downlink Control Information).
  • PDCCH includes a transmission format and resource allocation information of a downlink shared channel (DL-SCH), a transmission format and resource allocation information of an uplink shared channel (UL-SCH), a paging channel, Tx power control instruction set for individual terminals in the terminal group, Tx power control command, Tx power control command for each terminal in the terminal group, paging information on the P-SCH, system information on the DL-SCH, random access response transmitted on the PDSCH, And information for activating VoIP (Voice over IP).
  • DL-SCH downlink shared channel
  • UL-SCH uplink shared channel
  • paging channel Tx power control instruction set for individual terminals in the terminal group
  • Tx power control command Tx power control command for each terminal in the terminal group
  • paging information on the P-SCH system information on the DL-SCH, random access response transmitted on the PDSCH
  • VoIP Voice over IP
  • the DCI format may include a hopping flag, an RB allocation, a Modulation Coding Scheme (MCS), a Redundancy Version (RV), a New Data Indicator (NDI), a Transmit Power Control (DM-RS), a channel quality information (CQI) request, an HARQ process number, a TPMS (Transmitted Precoding Matrix Indicator), and a PMI (Precoding Matrix Indicator) confirmation.
  • MCS Modulation Coding Scheme
  • RV Redundancy Version
  • NDI New Data Indicator
  • DM-RS Transmit Power Control
  • CQI channel quality information
  • TPMS Transmission Precoding Matrix Indicator
  • PMI Precoding Matrix Indicator
  • the base station determines the PDCCH format according to the DCI to be transmitted to the UE, and adds a CRC (cyclic redundancy check) to the control information.
  • the CRC is masked with an identifier (e.g., radio network temporary identifier (RNTI)) according to the owner of the PDCCH or the purpose of use. For example, if the PDCCH is for a particular terminal, the identifier of the terminal (e.g., cell-RNTI (C-RNTI)) may be masked to the CRC. If the PDCCH is for a paging message, the paging identifier (e.g., paging-RNTI (P-RNTI)) may be masked to the CRC.
  • RNTI radio network temporary identifier
  • the system information RNTI (SI-RNTI) may be masked to the CRC. If the PDCCH is for a random access response, a random access-RNTI (RA-RNTI) may be masked in the CRC.
  • TPC-RNTI may be used when the PDCCH is for uplink power control, and the TPC-RNTI may be a TPC-PUCCH-RNTI for PUCCH power control and a TPC-PUSCH- RNTI. ≪ / RTI > When the PDCCH is for a multicast control channel (MCCH), a Multimedia Broadcast Multicast Service-RNTI (M-RNTI) may be used.
  • M-RNTI Multimedia Broadcast Multicast Service-RNTI
  • DCI Downlink Control Information
  • DCI formats 0 and 4 (hereinafter referred to as UL grant) are defined for uplink scheduling and DCI formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, and 2C DL grant) is defined.
  • the DCI format is divided into a hopping flag, RB allocation, Modulation Coding Scheme (MCS), Redundancy Version (RV), New Data Indicator (NDI), Transmit Power Control (TPC) (PMQ), a HARQ process number, a TPMI (Transmitted Precoding Matrix Indicator), and a PMI (Precoding Matrix Indicator) confirmation.
  • MCS Modulation Coding Scheme
  • RV Redundancy Version
  • NDI New Data Indicator
  • TPC Transmit Power Control
  • PMQ HARQ process number
  • TPMI Transmitted Precoding Matrix Indicator
  • PMI Precoding Matrix Indicator
  • a limited set of CCE locations where PDCCHs can be located for each terminal is defined.
  • a limited set of CCE locations where a terminal can locate its PDCCH may be referred to as a Search Space (SS).
  • the search space has a different size according to each PDCCH format.
  • UE-specific and common search spaces are separately defined. Since the BS does not provide the UE with information on where the PDCCH is located in the search space, the UE monitors the set of PDCCH candidates in the search space and searches for its PDCCH. Here, the monitoring means that the UE attempts to decode the received PDCCH candidates according to each DCI format. Finding the PDCCH in the search space is called blind detection or blind detection. Through blind detection, the UE simultaneously performs identification of the PDCCH transmitted thereto and decoding of the control information transmitted through the corresponding PDCCH.
  • FIG. 4 illustrates a structure of an uplink sub-frame that can be used in the present invention.
  • the uplink subframe includes a plurality of (e.g., two) slots.
  • the slot may include a different number of SC-FDMA symbols depending on the CP length. For example, in case of a normal CP, the slot may include 7 SC-FDMA symbols.
  • the UL subframe is divided into a data region and a control region in the frequency domain.
  • the data area includes a PUSCH and is used for transmitting a data signal such as voice.
  • the control area contains the PUCCH and is used to transmit control information.
  • the random access procedure is used to transmit the data in the uplink (short length). For example, the random access procedure is performed at the initial access in the RRC_IDLE state, the initial access after the radio link failure, the handover requesting the random access procedure, and the uplink / downlink data generation requiring the random access procedure during the RRC_CONNECTED state .
  • Some RRC messages such as a RRC Connection Request Message, a Cell Update Message, and a URA Update Message are also transmitted using a random access procedure.
  • Logical channels Common Control Channel (CCCH), Dedicated Control Channel (DCCH), and Dedicated Traffic Channel (DTCH) may be mapped to the transport channel RACH.
  • the transport channel RACH is mapped to a physical channel RACH (Physical Random Access Channel).
  • the physical layer When the MAC layer of the MS instructs the physical layer to transmit the PRACH, the physical layer first selects one access slot and one signature and transmits the PRACH preamble on the uplink.
  • the random access process is divided into a contention based process and a non-contention based process.
  • the terminal receives and stores information on random access from the base station through system information. Thereafter, if random access is required, the terminal transmits a random access preamble (also referred to as message 1 or Msg1) to the base station (S510).
  • a random access preamble also referred to as message 1 or Msg1
  • the BS transmits a random access response (message 2 or Msg2) to the MS in step S520.
  • the downlink scheduling information for the random access response message may be CRC-masked with a random access-RNTI (RA-RNTI) and transmitted on an L1 / L2 control channel (PDCCH).
  • RA-RNTI random access-RNTI
  • PDCCH L1 / L2 control channel
  • the UE receiving the downlink scheduling signal masked with the RA-RNTI can receive and decode the random access response message from the Physical Downlink Shared Channel (PDSCH). Thereafter, the terminal checks whether the random access response information indicated by the random access response message exists in the random access response message. Whether or not there is random access response information indicated to the user can be confirmed by whether or not there is a RAID (Random Access Preamble ID) for the preamble transmitted by the UE.
  • the random access response information includes a timing advance (TA) indicating timing offset information for synchronization, a radio resource allocation information used in uplink, a temporary identifier (e.g., Temporary C-RNTI) do.
  • TA timing advance
  • the UE Upon receiving the random access response information, the UE transmits uplink transmission (also referred to as message 3 or Msg3) including an RRC connection request message on the uplink shared channel (SCH) according to the radio resource allocation information included in the response information (S530).
  • the base station After receiving the uplink transmission from the terminal, the base station transmits a message for contention resolution (also referred to as message 4 or Msg4) to the terminal in operation S540.
  • the message for contention resolution may be referred to as a contention resolution message and may include an RRC connection establishment message.
  • the mobile station After receiving the contention resolution message from the base station, the mobile station transmits a connection establishment completion message (also referred to as message 5 or Msg 5) to the base station after completing connection setup in operation S550.
  • the base station can allocate a non-contention random access preamble to the UE before the UE transmits the random access preamble (S510).
  • a non-contention random access preamble may be allocated through a handover command or dedicated signaling such as a PDCCH. If the UE is allocated a non-contention random access preamble, the UE can transmit the allocated non-contention random access preamble to the Node B similarly to step S510.
  • the BS receives the non-contention random access preamble from the MS, the BS may transmit the random access response to the MS similar to step S520.
  • HARQ is not applied to the random access response (S520), but HARQ may be applied to a message for uplink transmission or contention resolution for a random access response. Therefore, the UE does not need to transmit ACK / NACK for the random access response.
  • a low-end / low-end terminal mainly focusing on data communication such as meter reading, water level measurement, utilization of surveillance cameras, and inventory report of vending machines.
  • These terminals seek to provide adequate throughput between connected devices despite their low device complexity and low power consumption and can be referred to as MTC (Machine Type Communication) or IoT (Internet of Things) terminals for convenience. And is briefly referred to as a UE in this specification.
  • the next generation system can perform communication using narrowband (or NB-IoT communication) in utilizing a cellular network or a third network.
  • the narrowband may be 180 kHz.
  • the UE (or the NB-IoT UE) or the eNB within the corresponding area may multiplex and transmit a single or a plurality of physical channels.
  • the NB-IoT UE may perform communication in an area where the channel environment is poor, such as under the bridge, seabed, and sea. In order to compensate for this, it is necessary to perform repetition of a specific channel (for example, ) And / or performing power boosting may be considered.
  • An example of the power amplification may be a form in which the frequency resources to be transmitted within a specific band are further reduced to drive the power per hour to a specific resource.
  • a specific channel is transmitted through an RB (resource block) composed of 12 REs
  • a specific RE is selected and allocated instead of an RE allocation for each RB, .
  • a method of performing communication by concentrating data and power in one RE in the RB can be referred to as a single-tone transmission scheme.
  • NB-IoT can be mixed with cellular IoT (or cIoT).
  • the NPRACH preamble refers to the PRACH preamble for NB-IoT supported by the LTE-A pro system, and may be referred to as a PRACH preamble.
  • the random access symbol group of FIG. 6 may be referred to as a (N) PRACH symbol group and is referred to simply as a symbol group.
  • the NPRACH preamble consists of four symbol groups (symbol group 0 to symbol group 3), and each symbol group can be composed of a CP (Cyclic Prefix) and a sequence part as illustrated in FIG.
  • the sequence portion may be composed of five subblocks, each subblock including the same symbol. For example, the same symbol may have a fixed symbol value of one.
  • the NPRACH preamble is transmitted using the designated time / frequency resource, and the time / frequency resource for the NPRACH preamble transmission can be set through the NPRACH configuration information.
  • the NPARCH configuration information may be transmitted to the terminal via an upper layer signal (e.g., RRC layer signal) or system information (e.g., SIB2).
  • the NPRACH configuration information may include the following information.
  • NPRACH start time eg, Or nprach-StartTime
  • the frequency domain for the NPRACH preamble transmission may be a subcarrier offset set via an upper layer signal (e.g., RRC layer signal) or system information (e.g., SIB2) ) And the number of subcarriers (e.g., ). ≪ / RTI > Each symbol group constituting the NPRACH preamble is transmitted without a gap, and frequency hopping is performed for each symbol group within the designated frequency domain.
  • Equation (1) Denotes the starting subcarrier index of the NPRACH preamble and is determined by Equation (2).
  • Equation (1) Represents the subcarrier offset and is determined by Equation (3).
  • Equation 2 Lt; / RTI >
  • Equation 3 Represents the subcarrier offset for symbol group 0 of the NPRACH preamble and is determined by equation (4).
  • I is determined by Expression (5), and Expression silver (E.g., the MAC layer).
  • Equation (5) ego Lt; / RTI >
  • the NPRACH preamble may be repeatedly transmitted a certain number of times (e.g., N in FIG. 6) for coverage enhancement or coverage extension.
  • the specific number of iterations can be set via an upper layer signal (e.g., RRC layer signal) or system information (e.g., SIB2).
  • RRC layer signal e.g., RRC layer signal
  • SIB2 system information
  • Four symbol groups (symbol group 0 to symbol group 3) constituting the NPRACH preamble are hopped for each symbol group to frequency positions determined using Equations 1 to 5, and after transmitting the NPRACH preamble for the first time, Th < / RTI > NPRACH preamble can also be frequency-hopped and transmitted based on equations (1) to (5).
  • the NPRACH preamble can be repeatedly transmitted a predetermined number of times (e.g., N) by applying the same method.
  • the frequency position of the first symbol group (i.e., symbol group 0) of each repeatedly transmitted NPRACH preamble can be randomly determined.
  • the guard time is not applied to the NPRACH preamble. Therefore, in the case of the NPRACH preamble illustrated in FIG. 6, the supported cell radius can be determined by considering the CP length instead of the guard time.
  • Cell radius (luminous flux) * (CP length / 2)
  • Table 1 shows approximate values of CP length and cell radius according to the NPRACH preamble format.
  • the NPRACH preamble format may have format 0, 1, and each NPRACH preamble format may have the same sequence length and different CP lengths.
  • the CP length may be set through an upper layer signal (e.g., RRC layer signal) or system information (e.g., SIB2), and the corresponding NPRACH preamble format may be determined according to the CP length.
  • RRC layer signal e.g., RRC layer signal
  • SIB2 system information
  • us represents microseconds and km represents kilometers.
  • a guard time can be given considering round trip delay (RTD) according to the cell radius.
  • RTD round trip delay
  • the BS can receive the PRACH preamble of each UE in the corresponding TTI
  • a protection time can be given.
  • Table 2 shows approximate values of CP length, GT length, and cell radius according to the preamble format of the existing LTE / LTE-A system.
  • the preamble format value is indicated by the PRACH configuration index.
  • Preamble format 1 may be transmitted in one TTI (e.g., 1 ms)
  • preamble formats 1 and 2 may be transmitted in two TTIs (e.g., 2 ms)
  • preamble format 3 may be transmitted in three TTIs Lt; / RTI > and ms represents milliseconds.
  • us represents microseconds and km represents kilometers.
  • the maximum cell radius supported by the current LTE system is 100.2 km. Therefore, in order for the UE for NB-IoT to perform an in-band operation using the LTE network, it is necessary to support at least the same level of cell radius.
  • FIG. 7 illustrates an uplink-downlink timing relation.
  • the base station may have to individually manage or adjust the uplink transmission timing of each terminal.
  • the management or adjustment of the transmission timing performed by the base station may be referred to as timing advance or time alignment.
  • the timing advance or timing alignment may be performed through a random access procedure as described above.
  • the base station can receive the random access preamble from the terminal and calculate the timing advance value using the received random access preamble.
  • the calculated timing advance value is transmitted to the terminal through the random access response, and the terminal can update the signal transmission timing based on the received timing advance value.
  • the base station may calculate a timing advance by receiving an uplink reference signal (e.g., SRS (Sounding Reference Signal)) periodically or randomly transmitted from the terminal, and the terminal may calculate a timing advance based on the calculated timing advance value Can be updated.
  • an uplink reference signal e.g., SRS (Sounding Reference Signal)
  • the base station can measure the timing advance of the UE through the random access preamble or the uplink reference signal and can inform the terminal of an adjustment value for timing alignment.
  • the adjustment value for timing alignment may be referred to as a timing advance command (TAC) or a timing advance value (TA value).
  • the transmission of the uplink radio frame i from the UE may start before the start of the corresponding downlink radio frame (N TA + N TAoffset ) ⁇ T s seconds.
  • N TA N TA + N TAoffset
  • T s T s
  • N TA N TA can be indicated by a timing advance command.
  • T s represents the sampling time.
  • the uplink transmission timing can be adjusted in multiples of 16T s .
  • the TAC may be given as 11 bits in the random access response and may indicate a value from 0 to 1282. [ N TA can be given as TA * 16.
  • the TAC is 6 bits and can indicate a value from 0 to 63.
  • N TA can be given as N TA, old + (TA-31) * 16.
  • the timing advance command received in subframe n may be applied from subframe n + 6.
  • the existing NB-IoT system is designed based on a GERAN (GSM EDGE Radio Access Network) network supporting a cell radius of 35 km
  • the cyclic prefix (CP) of the random access preamble is about 40 km It is designed to support only the cell radius.
  • CP cyclic prefix
  • LTE Long Term Evolution
  • the preamble CP can be extended to extend the maximum allowable cell radius of the random access preamble (NPRACH).
  • NPRACH random access preamble
  • the minimum length of the CP to support a cell radius of 100 km may be calculated according to Equation (8) based on Equation (6).
  • an extended CP In order to support the extended cell radius, an extended CP is referred to as an extended CP (E-CP).
  • E-CP extended CP
  • the length of the E-CP can be designed to have a slight margin in consideration of the delay spread.
  • a time gap of the same length (for example, 666.7 us) as that of the E-CP may be required to avoid overlapping the random access preamble received immediately after the base station from the neighboring sub-frame immediately after the base station, This time interval is referred to as a guard time (GT).
  • GT guard time
  • Both cyclic prefix and guard time are added to avoid interference between symbols.
  • the cyclic prefix and guard time are classified as overhead in terms of system throughput because they are signals added incidentally in terms of performance. Therefore, for more efficient preamble transmission, it is possible to reduce the percentage overhead of this cyclic permutation or guard time and to increase the portion (e.g., symbol or symbol group portion) corresponding to the preamble information excluding the cyclic prefix and guard time Can be considered.
  • timing advance TA
  • the initial timing advance is performed through a random access procedure.
  • the base station estimates an uplink transmission delay from the received preamble and transmits the random access response (RAR) message to the UE in the form of a timing advance command.
  • the terminal adjusts the transmission timing using the TA command received through the RAR message.
  • the random access preamble (or NPRACH preamble) for the NB-IoT is transmitted in a single carrier frequency hopping scheme and is used for both the timing estimation acquisition range and the accuracy .
  • the subcarrier spacing of the conventional random access preamble (or NPRACH preamble) is designed to allow timing estimation without ambiguity up to a radius of 40 km at 3.75 kHz.
  • the cell radius that can be supported without ambiguity can be calculated as follows.
  • the phase difference between signals transmitted on two subcarriers can be represented by 2 * pi * delta_f, and delta_f represents the subcarrier interval in units of Hz (Hertz).
  • the phase difference of signals transmitted on two subcarriers considering round trip delay can be expressed as 2 * pi * delta_f * tau_RTT, and tau_RTT indicates round trip delay.
  • tau_RTT indicates round trip delay.
  • the subcarrier interval should be reduced to 1.5 kHz or less in order to support the cell radius of 100 km since the cell radius of the conventional random access preamble (or NPRACH preamble) is 40 km, which enables timing estimation without ambiguity at 3.75 kHz subcarrier spacing. Or the interval between subcarriers is maintained at 3.75 kHz as in the case of the legacy preamble.
  • the problem of timing estimation ambiguity can be solved by applying fractional frequency hopping.
  • the cyclic prefix of the random access preamble should be extended to at least 666.7 us.
  • the subcarrier interval of the random access preamble should be reduced to 1.5 kHz or less, It is necessary to apply decimal frequency hopping while maintaining the kHz subcarrier interval to solve the timing estimation ambiguity.
  • the present invention is intended to enable the use of an NB-IoT system in a network supporting a maximum cell radius of an LTE network or an LTE system, and more particularly, to a network supporting a maximum cell radius of an LTE network or an LTE system,
  • This paper proposes a resource allocation and frequency hopping method.
  • a random access preamble supporting the extended cell radius (for example, 100 km) proposed in the present invention is defined as an 'enhanced' preamble, and in contrast, a conventional random access preamble is defined as' quot; legacy " preamble.
  • a legacy preamble may be referred to as a first preamble format
  • an enhanced preamble may be referred to as a second preamble format.
  • a random access preamble or (N) PRACH preamble or (N) PRACH signal or (N) PRACH can be mixed and can be briefly referred to as a preamble.
  • the (N) PRACH symbol group or the random access symbol group may be mixed and may be referred to simply as a symbol group.
  • a UE supporting a conventional NB-IoT (or a legacy preamble) may be referred to as a legacy UE, and a UE supporting an enhanced preamble (or both a legacy preamble and an enhanced preamble) quot; enhanced UE ").
  • the present invention is described based on a terminal / base station / system supporting NB-IoT, but the present invention is not limited thereto.
  • the present invention can be similarly applied to a terminal / base station / system that does not support NB-IoT communication.
  • the present invention can be applied to a terminal / base station / system supporting massive machine type communication (mMTC) as well as a general terminal / base station / system (e.g., LTE / LTE-A / / 5G system and a terminal / base station operable in the system).
  • mMTC massive machine type communication
  • a general terminal / base station / system e.g., LTE / LTE-A / / 5G system and a terminal / base station operable in the system.
  • a terminal / base station / system may be referred to as a terminal / base station / system supporting NB-IoT and a general terminal / base station / system not supporting
  • the enhanced preamble may be configured to increase the CP length to correspond to a plurality of symbols compared to the conventional preamble or to reduce the subcarrier interval by 3.75 / NkHz (N> 1) Contrast refers to a preamble designed to support a larger cell radius.
  • the enhanced preamble may be a new type of PRACH format added to the existing legacy preamble.
  • an improved preamble the number of symbols used in a CP in a symbol group constituting a random access preamble (or NPRACH preamble) for a conventional NB-IoT (e.g., see FIG. 6 and related description) can be increased.
  • a CP corresponding to a plurality of symbols in a symbol group is referred to as an E-CP (enhanced CP).
  • E-CP enhanced CP
  • the first three symbols of the six symbols of the legacy preamble may be used as CPs and five symbols may be used as sequence portions (e.g., see FIG. 8).
  • the UE transmits a random access preamble in a format including a CP portion corresponding to 3 symbol length and a sequence portion corresponding to 5 symbol length, and the base station transmits the first 3 symbols to an enhanced CP ) And performs preamble detection and timing estimation using the remaining 5 symbols except for the first 3 symbols.
  • the random access preamble format of FIG. 8 is only an example, and the present invention is not limited to the random access preamble format of FIG.
  • the subcarrier interval of the random access preamble can be reduced to 1.5 kHz or less to support a cell radius of 100 km without any ambiguity in timing estimation.
  • the subcarrier spacing of the enhanced preamble can be 3.75 / N kHz (N> 1 integer) considering additional delay spread and FDM time interference, and more specifically to a cell radius of 120 km
  • the method 1-1 of the present invention is a method of sharing a legacy NPRACH resource configuration.
  • the enhanced UE interprets the NPRACH resource configuration equally with the legacy UE and transmits the enhanced preamble therein. More specifically, the enhanced UE assumes a legacy NPRACH resource configuration, and iterates all the legacy NPRACH resources and continues to allocate the remaining repetitions of the improved preamble to the legacy NPRACH resources allocated in the next period. Fill one or more legacy NPRACH resource configurations in succession in the same manner until all the iterations of the enhanced preamble are all allocated.
  • FIG. 9 illustrates a method of constructing NPRACH resources according to method 1-1 of the present invention.
  • the NPRACH transmission position in the time domain can be indicated through the NPRACH configuration information.
  • the NPRACH preamble transmission is performed in radio frames 0, 4, 8, 3 < / RTI > Therefore, the NPRACH can be repeatedly transmitted by the repetition times indicated through the NPRACH configuration information at the indicated starting position through the NPRACH configuration information.
  • the improved UE can improve the NPRACH resource configuration After all the repetitive transmissions of the preamble are allocated to the current NPRACH transmission period, the remaining repetitive transmissions can be allocated to the next NPRACH transmission period.
  • the NPRACH transmission period includes information indicating the period of the NPRACH resource (e.g., Or NPRACH-Periodicity), and the NPRACH start position may be indicated by information indicating the NPRACH start time (e.g., Or nprach-StartTime).
  • the legacy NPRACH resources where the last iterative transmission of the enhanced preamble is performed can all be filled or partially filled, and can be filled from the beginning of the next legacy NPRACH resource the same as the legacy preamble if all are filled.
  • the following two methods can be considered as a method of transmitting an enhanced preamble to be transmitted next in case of partial filling.
  • Method 1-1-1 Same NPRACH How to transfer continuously within a resource configuration
  • the advanced preamble to be transmitted next can be transmitted immediately after the gap in the same period or immediately after the predetermined interval.
  • the gap of a predetermined interval may be used for a guard time, an uplink synchronization, or a channel sounding.
  • the enhanced UE should be instructed to start the enhanced preamble.
  • the information indicating the starting point of the enhanced preamble may have a value corresponding to a subframe index in the legacy NPRACH resource (or a value corresponding to a time offset from the beginning of the radio frame), or a start point in the legacy NPRACH resource to reduce the signaling overhead Limitations can only be given to limited locations.
  • the indication information may be transmitted (via PDCCH) in the form of higher layer signaling or DCI (Downlink Control Information).
  • the frequency domain for the next enhanced preamble to be transmitted may be set equal to the frequency domain for the previously transmitted advanced preamble.
  • FIG. 10 illustrates an improved preamble transmission method according to the method 1-1-1 of the present invention.
  • the transmission of the next enhanced preamble can be started continuously immediately within the same period as the transmission end position of the already transmitted advanced preamble.
  • the transmission of the next enhanced preamble may start with a gap of a predetermined interval within the same period as the transmission end position of the already transmitted advanced preamble.
  • Method 1-1-2 Improved Preamble The starting point of the iteration NPRACH How to Restrict to Resource Configuration Entry Point
  • This method is a method for restricting the starting point of the improved preamble to the starting point of the legacy NPRACH resource configuration in the same manner as the legacy preamble.
  • the method 1-1 of the present invention is advantageous in that it does not affect the operation of the legacy UE even if the legacy UE and the enhanced UE coexist because the method of the present invention adheres to the legacy NPRACH resource configuration method.
  • Method 1-2 of the present invention is a method for partially sharing the legacy NPRACH resource configuration. For example, it is possible to share a period and a starting point of a legacy NPRACH resource configuration, and iterations can be interpreted and applied as an improved preamble criterion.
  • the transmission period and the starting point of the enhanced preamble are information that indicates the period of the NPRACH resource according to the legacy NPRACH resource configuration (e.g., Or nprach-Periodicity) and information indicating the NPRACH start time (e.g., Or nprach-StartTime), and the number of repetitions of the enhanced preamble is determined based on information indicating the number of NPRACH repetitions included in the legacy NPRACH resource configuration (e.g., Or numRepetitionsPerPreambleAttempt).
  • the number of repetitions can be determined by adding or subtracting a specific offset to the value indicated by the value.
  • an enhanced preamble Can be determined by multiplying or dividing by a specific multiple the indicated value.
  • the period and the start point of the improved preamble are the same as those of the legacy preamble, and the end point may be different according to the repetition method of the improved preamble.
  • the end point of the enhanced preamble is faster than the legacy preamble, there is no conflict with the uplink / downlink transmission subframe of the legacy UE, which is not a problem in terms of backward compatibility.
  • the end point of the enhanced preamble is larger than the legacy preamble in terms of time, collision may occur with the uplink / downlink transmission subframe of the legacy UE. In such a situation, it can not be expected that the legacy UE will know the end point of the enhanced preamble.
  • the base station can be solved using a method of scheduling to avoid collision with the enhanced preamble using the existing scheduling method of the legacy UE .
  • Method 1-2 can have the following advantages over Method 1-1.
  • some common requirements may be required for the form of time / frequency resource occupation of the enhanced preamble for efficient operation.
  • the requirement may be that the repeat unit of the legacy preamble and the enhanced preamble should be the same in time.
  • the enhanced preamble is smaller than the subcarrier spacing of the legacy preamble, or if the decimal frequency hopping is applied, a plurality of symbols can operate as one unit on the basis of symbols in the legacy preamble. In this case, The constraint can be followed.
  • the constraint may be a preamble boundary alignment or the like, which means that the legacy preamble and the enhanced preamble have the same temporal length and match the starting point equally.
  • the number of symbol groups in the preamble can be adjusted, the number of symbols in the symbol group can be adjusted, or both the number of symbols and the number of symbols can be adjusted.
  • Method 1-1 can be applied to such a constraint, while Method 1-2 can be applied without restriction to such an improved preamble structure.
  • the method 1-3 of the present invention is a method for setting up an improved NPRACH resource configuration independent of the legacy NPRACH resource configuration.
  • the improved NPRACH resource configuration sets the cycle, the starting point, the number of iterations, etc., independently of the legacy resource configuration.
  • the indication method such as period, start point, repetition number, etc. can be used by using the legacy NPRACH resource configuration as it is and with different interpretation, or by defining an independent indication method.
  • they may be allocated independently, but all or some of them may belong to legacy NPRACH resources. Or to avoid conflict with the legacy preamble to avoid legacy NPRACH resources.
  • the UE receives the legacy NPRACH configuration information and the values indicated by the legacy NPRACH configuration information (e.g., , , ),
  • the enhanced NPRACH resource configuration may be set by differently interpreting the indicated values.
  • the enhanced NPRACH resource configuration can be set to a value obtained by adding or subtracting a specific offset to the period, start point, and repetition frequency set by the legacy NPRACH resource configuration.
  • the enhanced NPRACH resource configuration may be set to a value multiplied or divided by a specific value for the period, starting point, and number of iterations set by the legacy NPRACH resource.
  • the base station does not send the enhanced NPRACH configuration information to the UE, and the UE does not receive the enhanced NPRACH configuration information.
  • the UE can receive the enhanced NPRACH configuration information together with the legacy NPRACH configuration information.
  • the UE determines the values indicated by the legacy NPRACH configuration information (e.g., , , ) And sets the legacy NPRACH resource configuration based on the values indicated by the enhanced NPRACH configuration information (e.g., , , ),
  • the legacy NPRACH resource configuration can be set.
  • the resource configuration can be set so as to avoid collision between the legacy preamble and the enhanced preamble.
  • the NPRACH resource configuration of the enhanced preamble can be transmitted by FDM with the legacy NPRACH resource configuration.
  • the base station allocates some frequency regions of 180 kHz (or 1 RB) as NPRACH resources for transmitting the legacy preamble, and allocates some of the remaining or remaining portions as NPRACH resources for the enhanced preamble transmission Can be assigned.
  • the legacy UE since the legacy UE is allocated a certain frequency region in the same NPRACH resource configuration scheme as the existing UE, the legacy UE can operate without being affected by the FDM with the enhanced preamble.
  • the enhanced preamble may perform repetition and / or frequency hopping in all or a portion of the allocated NPRACH resources in the same manner as the legacy preamble.
  • Method 2-1 Improved Preamble Or enhanced NPRACH How to set frequency resource
  • the interval of frequency grids that can be selected as the starting frequency (or tone) position within the NPRACH resource of the enhanced preamble or the enhanced preamble is the frequency resource interval of the legacy NPRACH or the NPRACH resource of the legacy preamble (E.g., 3.75 kHz) that can be selected as the start frequency (or tone) position in the frequency domain.
  • the frequency grid spacing that can be selected as the starting frequency (or tone) position in the frequency resource of the enhanced preamble or the NPRACH resource of the enhanced preamble is the sub-carrier spacing or minimum hop distance of the enhanced preamble (e.g., 1.25 kHz ). ≪ / RTI >
  • the enhanced UE When the enhanced UE (or a UE supporting an enhanced preamble) is configured to transmit or transmit an enhanced preamble in a legacy NPRACH contention-based region, it can avoid collisions with the legacy preamble or minimize interference (Or tone) location within the NPRACH resource of the enhanced NPRACH frequency resource or the enhanced preamble is selected as the starting frequency (or tone) position within the NPRACH resource of the legacy NPRACH or the legacy NPRACH, It can be set to the same interval as the possible frequency grid (eg, 3.75 kHz).
  • the possible frequency grid eg, 3.75 kHz
  • a frequency grid that can be selected as the starting frequency (or tone) position within the NPRACH resource of the enhanced NPRACH frequency resource or the enhanced preamble is selected as the starting frequency (or tone) position within the NPRACH resource of the legacy NPRACH or the NPRACH resource of the legacy preamble (E.g., + delta kHz or -delta) from a frequency grid (selectable from the frequency grid of the legacy NPRACH or NPRACH resource of the legacy preamble to the starting frequency (or tone) position) kHz frequency offset).
  • the magnitude (e.g., delta value) of a particular frequency offset value may be set equal to the sub-carrier spacing or minimum hop distance of the enhanced preamble (e.g., 1.25 kHz).
  • the selectable frequency grid spacing in the NPRACH resource of the enhanced NPRACH resource or the enhanced preamble in the NPRACH resource of the enhanced preamble is greater than the selectable frequency grid spacing in the start frequency (or tone) position within the NPRACH resource of the legacy NPRACH resource or legacy preamble Can be set to a small value.
  • the selectable frequency grid interval to the start frequency (or tone) position within the NPRACH resource of the enhanced NPRACH resource or the enhanced preamble is set equal to the subcarrier interval or minimum hopping distance of the enhanced preamble (e.g., 1.25 kHz) .
  • a frequency grid that can be selected as the starting frequency (or tone) position within the NPRACH resource of the enhanced preamble or the enhanced preamble includes a start frequency (or tone) within the NPRACH resource of the legacy (or enhanced) preamble or the legacy (E.g., a frequency offset of + delta kHz or -delta kHz) from a frequency grid (e.g., 3.75 kHz) that is selectable by a position (or tone) position.
  • the magnitude of the frequency offset value (e.g., delta value) may be set equal to the sub-carrier spacing or minimum hopping distance of the enhanced preamble (e.g., 1.25 kHz).
  • the frequency offset of the enhanced preamble or the enhanced NPRACH may be set to be cell-specific such that all UEs in the same cell have the same frequency offset.
  • all UEs having the same transmission time point or the same NPRACH time resource set in association with the transmission start time of the enhanced preamble or the enhanced NPRACH time resource may be set to have the same frequency offset.
  • it must have the same value if it satisfies either of the above two conditions (for example, it should be in the same cell, the same transmission time, or the same NPRACH time resource) It can be set to have an offset value. For example, in the latter case, it may be possible to set the same frequency offset value for all UEs sharing the improved NPRACH time resources or the starting point of the improved preamble in the same cell.
  • the RAPID of the enhanced preamble or NPRACH may be a sub-carrier interval or a minimum hop distance of the preamble (continuously) for the entire NB-IoT system bandwidth or for a specific frequency region (where preamble transmission or NPRACH frequency resource setting is possible) (Eg RAPID setting method 2-3-1) by assigning the index in ascending or descending order of the frequency value at intervals of (for example, 1.25 kHz).
  • the index can be set only within a system bandwidth, or in a frequency region where preamble transmission or NPRACH frequency resource setting is possible, by assigning an index only at a frequency position actually used for preamble transmission or NPRACH frequency resource setting (RAPID setting method 2-3 -2). Therefore, the set of frequency positions to which the ID is assigned by the RAPID setting method 2-3-2 may be a subset or a subset of the set of frequency positions to which the ID is assigned by the RAPID setting method 2-3-1.
  • the RAPID is given priority to the frequency resources of the legacy preamble or NPRACH in ascending or descending order of the frequency values, and the improved preamble can be assigned to the increased preamble in ascending or descending order of the frequency value have.
  • 0 to M-1 may be the legacy preamble or NPRACH (Tone) of frequency resources or preamble transmissions in the NPRACH resource and is allocated in ascending or descending order of the frequency values, and for the frequency resource or preamble transmission of the preamble or NPRACH from M to N-1, (Tone) that can be selected in the ascending or descending order of the frequency value.
  • the RAPID setting method can be set differently according to the area of the NPRACH frequency resource.
  • the NPRACH frequency resource (or frequency grid) interval, the NPRACH frequency offset, and the like may vary when the enhanced preamble is transmitted to the legacy NPRACH contention-based area and the legacy NPRACH contention area, Can vary.
  • the RAPID setting method may be different depending on whether the enhanced preamble and the legacy preamble use the same RA-RNTI. For example, if the same RA-RNTI is not used, the RAPID of the enhanced preamble can be assigned to the start frequency (tone) sequentially starting from zero. On the other hand, when the same RA-RNTI is shared, it may be sequentially allocated to a starting frequency (tone) at which an enhanced preamble can be transmitted after a specific value (offset) in the corresponding RA-RNTI in order to distinguish from a legacy preamble . The particular value or offset may be the largest of all available RAPID values for any legacy preamble.
  • the RA-RNTI may be determined based on the index information of the first (or starting) radio frame that initiates repeated transmission of the random access preamble.
  • the legacy UE may determine the RA-RNTI based on Equation (9), where SFN_id represents the index information of the first (or starting) radio frame that initiates repeated transmission of the random access preamble, floor () Denotes a floor function that discards decimal places.
  • RA-RNTI 1 + floor (SFN_id / 4)
  • the enhanced UE may have a frequency offset (for the legacy preamble or an enhanced preamble of 3.75 kHz frequency grid), a frequency hopping pattern, or a hopping direction, and can be applied to an improved preamble or an improved NPRACH transmission.
  • Method 2-4 Improved Preamble Or enhanced NPRACH How to set time resources
  • one symbol group is composed of four symbols and a preamble is composed of four symbol groups
  • the enhanced UE random access procedure may use a four-step contention-based random access procedure as with legacy UEs (e.g., see FIG. 5 and related discussion).
  • the conventional contention-based random access procedure and the conventional transmission message at each stage are as follows.
  • Msg1 RA preamble transmission (e.g., refer to S510 in FIG. 5)
  • Msg2 RAR (TA command, UL grant for L2 / L3 message, etc.) (e.g., see S520 in FIG. 5)
  • Msg3 L2 / L3 message (RRC connection request, TAU, UE id, etc.) (e.g., S530 in FIG. 5)
  • Msg4 RRC connection setup (e.g., UE id, etc.) (e.g., see S540 in FIG. 5)
  • Msg5 RRC connection setup complete (e.g., see S550 in FIG. 5)
  • the base station computes TA information and RA-RNTI through the received enhanced preamble.
  • the base station transmits a message (RAR) including the TA command and the msg3 scheduling information to the UE.
  • the UE receives the RAR information corresponding to itself using the RA-RNTI in the common search space.
  • the RA-RNTI is calculated based on the preamble transmission start point and may be a value that the UE can know in advance.
  • the UE applies a timing adjustment to the msg3 according to the msg3 scheduling information and the TA command received in the step 2 of msg, and transmits the uplink through the timing adjustment.
  • Msg3 includes UE identification information (or UE id information) for contention resolution.
  • the MS successfully receives the msg3
  • the BS transmits the contention resolution message including the UE identification information (or the UE id information) in the downlink. If the UE confirms its UE identification information (or UE id information) included in the contention resolution message in step 4, it confirms that the contention is resolved.
  • the enhanced preamble shares the NPRACH resources with the legacy preamble, the enhanced preamble can be transmitted across multiple legacy NPRACH resources, where there may be ambiguity problems with the NPRACH resource location where the enhanced preamble is initiated.
  • Method 3-1 Improved Preamble send Resolve ambiguity about starting point
  • the method 3-1 of the present invention is a method for solving the ambiguity problem that may arise when an enhanced preamble is transmitted over a plurality of legacy NPRACH resource periods by setting a period in which the enhanced preamble transmission can be started among the configured NPRACH resources, To the UE.
  • the resource cycle index i can be defined as a counter value that increments by one for every NPRACH period.
  • the k value indicated from the base station may be sent in higher layer signaling (e.g., RRC signaling) with the enhanced UE's NPRACH resource configuration information, or in DCI form (via the PDCCH) to the UE.
  • Method 3-2 Improved Preamble send Resolve ambiguity about starting point
  • the starting point of the enhanced preamble may be specified in the specification by limiting the starting point of the enhanced preamble to reduce the signaling overhead.
  • mod represents a modulo function.
  • both the base station and the UE can be values that can be known by calculation.
  • the following operation can be considered when the value of the RA-RNTI corresponding to the legacy preamble and the enhanced preamble is the same and can not be distinguished.
  • Method 4-1 Legacy Preamble and Improved The preamble The same RA- RNTI How to respond when you have
  • the UE may rely on the contention resolution process of the contention-based random access procedure as a first method.
  • the UE Upon receiving the RA-RNTI of its own preamble, the UE transmits the UE identification information (or UE id) on the uplink according to the msg3 scheduling information included in the RAR message and receives its UE identification information (or UE id)
  • the competition solution can be completed.
  • the method 4-1 can not confirm the improved preamble transmission up to the step of msg 4. Considering the importance of power consumption and latency reduction in the NB-IoT, we can confirm the improved preamble transmission before msg4 as follows You can consider how you can.
  • Method 4-2 Legacy Preamble and Improved The preamble The same RA- RNTI How to respond when you have
  • the second way is to add a field to indicate whether the RAR message is an enhanced preamble or a legacy preamble.
  • a flag for distinguishing the enhanced preamble and the legacy preamble from the reserved field of the RAR message may be transmitted and distinguished.
  • the enhanced UE is a RAR corresponding to a legacy preamble, it can reduce power consumption or delay by performing retransmission or the next operation before going to step # 4.
  • Method 4-3 Legacy Preamble and Improved The preamble The same RA- RNTI How to respond when you have
  • the RA-RNTI can be classified into RA-RNTI by adding RA-RNTI distinguished from the legacy preamble to the improved preamble in the third method.
  • RA-RNTI for convenience, referred to as e-RA-RNTI
  • e-RA-RNTI for the enhanced preamble may be in the form of an offset to the legacy RA-RNTI (e.g., see Equation 9 and related description)
  • e-RA-RNTI RA-RNTI + offset
  • the offset for e-RA-RNTI classification may be a large value without confusion with the legacy RA-RNTI.
  • the offset may have a value of 512, which corresponds to half the system frame number.
  • the e-RA-RNTI can be used by inverting certain bits or bits such as the MSB (Most Significant Bit) of the legacy RA-RNTI.
  • the offset value may be a fixed value, a value semi-statically set by higher layer signaling (e.g., RRC signaling), or a value dynamically signaled (via the PDCCH) by DCI or the like.
  • the offset value may be a value considering the number of times of preamble repetition.
  • an offset value can be set so as to be based on a point other than the preamble transmission start point (e.g., a point at which transmission ends).
  • it may be specified in the specification to calculate the e-RA-RNTI value based on a point other than the starting point of the preamble transmission (for example, the point at which the preamble transmission ends).
  • Method 4-4 Legacy Preamble and Improved The preamble The same RA- RNTI How to respond when you have
  • the calculation method of the e-RA-RNTI of the method 4-3 can be applied to both the RA-RNTI for the legacy preamble and the e-RA-RNTI for the enhanced preamble.
  • the offset value may use the same value for RA-RNTI and e-RA-RNTI, or different values without confusion may be applied.
  • a RAR message may be sent and received after the NPRACH resource of the last period.
  • the NPRACH resource period is set to be long in order to increase the data transmission throughput, the delay may become excessively long, which is also disadvantageous in terms of power consumption.
  • method 5 includes setting up a RAR window for each NPRACH resource cycle to send a RAR message.
  • the RAR information is transmitted to the UE using the RAR window in the corresponding period. If the UE confirms the RAR window at every cycle and confirms the RA-RNTI, the UE can confirm the success of the preamble transmission by checking the RAR message, and perform the next step such as msg3 transmission. If the NPRACH resource of the next cycle has completed the RA procedure before, the UE may stop the NPRACH transmission of the next cycle.
  • the RA process may be continued, or the RA process may be dropped or postpone and the NPRACH transmission of the cycle may continue. If the RA process is postpone, the RA process can be continued after completing the NPRACH transmission of the corresponding period.
  • the RA-RNTI used in the multiple RAR window may be calculated based on the initial transmission NPRACH of the enhanced preamble, or may be calculated based on the starting point of the corresponding NPRACH period.
  • each RA-RNTI of multiple RAR windows can be used separately to distinguish RA-RNTIs within multiple RAR windows.
  • the RA-RNTI of the multiple RAR window may contain information that can include or approximate the NPRACH resource period index value.
  • Figure 11 illustrates a flowchart of a method of performing a random access procedure in accordance with the present invention. Although described in the center of the UE for convenience of explanation, a corresponding operation can be performed by the base station.
  • the UE receives NPRACH configuration information.
  • the UE may configure resources for random access preamble transmission according to a preamble format indicated by the NPRACH configuration information among the first preamble format and the second preamble format.
  • the UE may receive the first NPRACH configuration information indicating the resource configuration for the legacy preamble format and the second NPRACH configuration information indicating the resource configuration for the enhanced preamble format.
  • the UE may configure a resource for a legacy preamble format according to the first NPRACH configuration information, and configure resources for an enhanced preamble format according to a second NPRACH configuration information.
  • step S1102 the UE may configure a resource for random access preamble transmission according to method 1-1 or method 1-2. Alternatively, in step S1102, the UE may configure a resource for random access preamble transmission according to the method 1-3 or the method 1-4.
  • the method 2-1 to the method 2-4 according to the present invention can be applied independently or together with the method 1-1 to the method 1-4 according to the concrete resource configuration method.
  • one symbol length for the enhanced preamble format may correspond to three times the length of one symbol for the legacy preamble format (e.g., see method 2-4), the frequency grid spacing for the legacy preamble format is 3.75 kHz and the frequency grid spacing for the enhanced preamble format may be set to 1.25 kHz (e.g., see method 2-1).
  • the present invention is not limited to this example, and methods 2-1 to 2-4 and methods 1-1 to 1-4 may be applied to the present invention in combination or independently.
  • the UE may transmit a random access preamble based on the received NPRACH configuration information. More specifically, the UE may transmit a random access preamble according to a preamble format indicated by the NPRACH configuration information among a first preamble format and a second preamble format.
  • the UE transmits a random access preamble according to the first NPRACH configuration information. If the UE supports the enhanced preamble format The random access preamble can be transmitted according to the second NPRACH configuration information.
  • the UE does not support an enhanced preamble (or if the UE is a legacy UE), it transmits a random access preamble in a legacy preamble format based on the first NPRACH configuration information, and if the UE supports an enhanced preamble
  • the random access preamble can be transmitted in an improved preamble format based on the second NPRACH configuration information.
  • the method 3-1 or the method 3-2 according to the present invention can be applied to solve the ambiguity about the transmission start point of the improved preamble when transmitting the random access preamble.
  • the UE may receive the RAR in response to the random access preamble. Specifically, the UE can detect the DCI for RAR reception using the RA-RNTI, and the methods 4-1 to 4-4 according to the present invention for detecting when the legacy preamble and the enhanced preamble have the same RA-RNTI Can be applied.
  • Method 5 according to the present invention can be applied to reduce the power and delay of the RA process.
  • FIG. 12 illustrates a base station and a terminal that can be applied to the present invention.
  • a wireless communication system includes a base station (BS) 1210 and a terminal (UE) 1220. If the wireless communication system includes a relay, the base station or the terminal may be replaced by a relay.
  • BS base station
  • UE terminal
  • the base station 1210 includes a processor 1212, a memory 1214, and a radio frequency (RF) transceiver 1216.
  • the processor 1212 may be configured to implement the procedures and / or methods suggested by the present invention.
  • Memory 1214 is coupled to processor 1212 and stores various information related to the operation of processor 1212.
  • the RF transceiver 1216 is coupled to the processor 1212 and transmits and / or receives wireless signals.
  • the terminal 1220 includes a processor 1222, a memory 1212, and a radio frequency unit 1226.
  • the processor 1222 may be configured to implement the procedures and / or methods suggested by the present invention.
  • Memory 1212 is coupled to processor 1222 and stores various information related to the operation of processor 1222.
  • the RF transceiver 1226 is coupled to the processor 1222 and transmits and / or receives radio signals.
  • the specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network including a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station.
  • Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof.
  • an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.
  • ASICs application specific integrated circuits
  • DSPs digital signal processors
  • DSPDs digital signal processing devices
  • PLDs programmable logic devices
  • the methods according to the present invention may be implemented in software code, such as modules, procedures, functions, etc., that perform the functions or operations described above.
  • the software code may be stored on a computer readable medium in the form of instructions and / or data and may be executed by the processor.
  • the computer-readable medium may be located inside or outside the processor, and may exchange data with the processor by various means already known.
  • the present invention can be used in a wireless communication apparatus such as a terminal, a base station, and the like.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé de réalisation, par un terminal, d'un processus d'accès aléatoire dans un système de communication sans fil prenant en charge des premier et second formats de préambule, et un appareil associé. En particulier, la présente invention concerne un procédé comprenant : une étape de réception d'informations de configuration d'un canal d'accès aléatoire physique à bande étroite (NPRACH) ; et une étape de transmission d'un préambule d'accès aléatoire sur la base d'un format de préambule indiqué par les informations de configuration de NPRACH des premier et second formats de préambule, la longueur d'un symbole du second format de préambule correspondant à trois fois la longueur d'un symbole du premier format de préambule et le premier format de préambule ayant un espacement de grille de fréquence de 3,75 kHz et le second format de préambule ayant un espacement de grille de fréquence de 1,25 kHz et un appareil pour celui-ci.
PCT/KR2018/009127 2017-08-09 2018-08-09 Procédé de réalisation d'un processus d'accès aléatoire et appareil associé Ceased WO2019031889A1 (fr)

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KR1020207005134A KR20200029580A (ko) 2017-08-09 2018-08-09 랜덤 접속 과정을 수행하는 방법 및 이를 위한 장치
US16/637,645 US11166322B2 (en) 2017-08-09 2018-08-09 Method for performing random access process and apparatus therefor
EP18843479.9A EP3668250A4 (fr) 2017-08-09 2018-08-09 Procédé de réalisation d'un processus d'accès aléatoire et appareil associé

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CN112769442A (zh) * 2021-01-06 2021-05-07 上海守正通信技术有限公司 一种支持多种前导码的5g prach接收机数字前端及算法
CN113170510A (zh) * 2019-04-30 2021-07-23 华为技术有限公司 一种通信方法及装置
CN114208327A (zh) * 2019-08-14 2022-03-18 株式会社Ntt都科摩 终端以及通信方法
US11962446B2 (en) 2019-10-15 2024-04-16 Beijing Xiaomi Mobile Software Co., Ltd. Method and apparatus for configuring physical random access channel

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Cited By (4)

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CN113170510A (zh) * 2019-04-30 2021-07-23 华为技术有限公司 一种通信方法及装置
CN114208327A (zh) * 2019-08-14 2022-03-18 株式会社Ntt都科摩 终端以及通信方法
US11962446B2 (en) 2019-10-15 2024-04-16 Beijing Xiaomi Mobile Software Co., Ltd. Method and apparatus for configuring physical random access channel
CN112769442A (zh) * 2021-01-06 2021-05-07 上海守正通信技术有限公司 一种支持多种前导码的5g prach接收机数字前端及算法

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