RU2790972C2 - Communication devices and communication methods for random access - Google Patents

Abstract

FIELD: communications.

SUBSTANCE: apparatus comprises a terminal containing a circuit which, during operation, generates a first random access preamble; and a transmitter that, during operation, transmits the first random access preamble to the base station in the first event (RO) of the physical random access channel (PRACH) among the plurality of candidate ROs, the plurality of candidate ROs being determined based on the PRACH configuration information received from the base station. The first RO is assigned in the first frequency section, where the first frequency section is equal to the first sub-band in which the listen procedure is performed before transmitting (LBT) at the terminal.

EFFECT: technical result consists in increasing the reliability of establishing a random access procedure.

22 cl, 16 dwg

Description

FIELD OF TECHNOLOGY

[1] The present invention relates to random access devices and methods for 5G communications, and more particularly to communication devices and methods for establishing a Random Access Channel (RACH) procedure in a New Radio (New Radio, NR) operating in unlicensed bands.

BACKGROUND OF THE INVENTION

[2] In 5G standardization, the 3rd Generation Partnership Project (3GPP) consortium discussed NR access technology, which is not necessarily backward compatible with Long Term Evolution (LTE)/LTE-Advanced. In NR, as in LTE with access using licensed bands (LTE License-Assisted Access, LTE-LAA), operations are expected in unlicensed bands (for example, NR-U).

[3] In unlicensed bands, channel access requires a Listen Before Ttalk (LBT) procedure depending on country, frequency and conditions. However, communication devices and communication methods for establishing a RACH procedure in the unlicensed bands in which LBT is provided have not been sufficiently discussed.

[4] Therefore, there is a need for communication devices and methods that can overcome the aforementioned shortcomings in order to provide efficient and reliable communication for establishing a RACH procedure in NR operating in unlicensed bands. In addition, other desirable features and characteristics will become apparent from the following detailed description and the appended claims in conjunction with the accompanying drawings.

DISCLOSURE OF THE INVENTION

[5] One non-limiting implementation example facilitates the efficient and reliable establishment of a random access procedure (RACH).

[6] In accordance with one aspect, the methods disclosed herein provide a communication device. The communication device is a terminal. The terminal contains a circuit that, during operation, generates the first random access preamble; and a transmitter that, during operation, transmits the first random access preamble to the base station in the first Physical Random Access Channel (PRACH) occasion (RO) event among the plurality of potential ROs. A set of potential ROs are determined based on the PRACH configuration information received from the base station. In accordance with an aspect, a first RO is assigned in a first frequency span, the first frequency span being equal to the first subband in which the listen-before-transmit (LBT) procedure is performed at the terminal.

[7] In accordance with yet another aspect, the methods disclosed herein provide a communications device. The communication device is a base station. The base station contains a circuit that determines the PRACH configuration during operation, and the PRACH configuration contains a plurality of potential ROs; and a receiver that, during operation, receives from the terminal the first random access preamble on the first RO among the plurality of potential ROs. In accordance with this aspect, the first RO is assigned to the first frequency section, and the first frequency section is equal to the first subband in which the LBT procedure is performed at the terminal.

[8] In accordance with yet another aspect, the methods disclosed herein provide a communication method. The communication method includes generating a first random access preamble at the terminal; and transmitting, from the terminal, the first random access preamble to the base station in the first RO among the plurality of candidate ROs, the plurality of candidate ROs being determined based on the PRACH configuration information received from the base station, the first RO being assigned in the first frequency section, where the first the frequency span is equal to the first subband in which the LBT procedure is performed at the terminal.

[9] In accordance with yet another aspect, the methods disclosed herein provide another method of communication. The communication method includes determining a PRACH configuration at a base station, wherein the PRACH configuration contains a plurality of potential ROs; and receiving at the base station the first random access preamble in the first RO among the plurality of potential ROs, wherein the first RO is assigned in the first frequency section, where the first frequency section is equal to the first subband in which the LBT procedure is performed at the terminal.

[10] It should be noted that general or specific implementations may be implemented as a system, method, integrated circuit, computer program, storage medium, or any selective combination thereof.

[11] Additional benefits and advantages of the disclosed embodiments will become apparent from the description of the invention and the drawings. Benefits and/or advantages may be achieved individually through various embodiments and features in the description and drawings, and it is not necessary to have all of them in order to obtain one or more of such benefits and/or advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

[12] Embodiments of the present invention will be easier to understand and more obvious to a person skilled in the art after the following written description, given by way of example only, and in conjunction with the drawings, in which:

[13] FIG. 1 shows signal flow in accordance with an exemplary method 100 involving a four-way random access channel (RACH) procedure between a base station and a terminal.

[14] FIG. 2a shows an example of Physical Random Access Channel (PRACH) events (RO) defined in the time and frequency domains and used to transmit MSG1 in a 4-round RACH procedure on an unlicensed carrier having more than one frequency slot. In this example, the ROs are distributed over more than one frequency section and are used to establish one RACH procedure (interchangeably referred to as a single RACH procedure).

[15] FIG. 2b shows another example of ROs defined in the time and frequency domains and used to transmit MSG1 in a 4-round RACH procedure on an unlicensed carrier having more than one frequency slot. In this example, the ROs are distributed over more than one frequency section and are used to establish multiple RACH procedures (interchangeably referred to as a multiple RACH procedure).

[16] FIG. 3a shows an example of a PRACH configuration on a licensed carrier in accordance with NR technology. As shown in this example, PRACH is configured for each carrier.

[17] FIG. 3b shows a scenario in which the ROs are underutilized when the PRACH configuration according to the NR technology shown in FIG. 3a is used on an unlicensed carrier.

[18] FIG. 4a shows a schematic example of a base station for establishing a RACH procedure according to embodiments. In this example, the base station may be referred to interchangeably as ngNodeB (gNB).

[19] FIG. 4b shows a schematic example of a terminal for establishing a RACH procedure according to embodiments. In this example, a terminal may be referred to interchangeably as a user equipment.

[20] FIG. 5 shows an example of a PRACH configuration to maximize RO availability within an unlicensed carrier RACH procedure in accordance with various embodiments of the present invention. As shown in this example, PRACH is configured for each frequency section on a carrier.

[21] FIG. 6 depicts an implementation of the PRACH configuration shown in FIG. 5. In this PRACH configuration embodiment, Synchronization Signal Block (SSB) to RO mapping (which is interchangeably referred to as SSB to RO mapping or SSB to RO mapping) is performed respectively for each of the frequency spans that are configured with PRACH.

[22] FIG. 7a shows another implementation of the PRACH configuration shown in FIG. 5. In this embodiment of the PRACH configuration, the mapping of SSB to RO is performed on a plurality of frequency sections that are configured with PRACH.

[23] FIG. 7b shows an alternative PRACH configuration shown in FIG. 7a, in which SSB to RO mapping is performed on a plurality of frequency sections according to an alternative SSB to RO mapping rule.

[24] FIG. 7c shows an alternate implementation of the PRACH configuration shown in FIG. 7a and 7b, in which SSB to RO mapping is performed on a plurality of frequency sections according to an alternative SSB to RO mapping rule.

[25] FIG. 7d shows an alternative implementation of the PRACH configuration shown in FIG. 7a, 7b and 7c, in which the SSB to RO mapping is performed on a plurality of frequency sections according to an alternative SSB to RO mapping rule.

[26] FIG. 7e shows another implementation of the PRACH configuration shown in FIG. 7a, 7b, 7c, and 7d, in which the SSB to RO mapping is performed on a plurality of frequency sections according to yet another SSB to RO mapping rule.

[27] FIG. 8 shows another schematic example of a base station that may be implemented to establish a RACH procedure on an unlicensed carrier in accordance with the various implementations shown in FIG. 5-7e.

[28] FIG. 9 shows another schematic example of a terminal that may be implemented to establish a RACH procedure on an unlicensed carrier in accordance with the various implementations shown in FIG. 5-7e.

[29] Those skilled in the art will appreciate that elements in the figures are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in illustrations, block diagrams, or block diagrams may be exaggerated relative to other elements to help better understand the present embodiments.

IMPLEMENTATION OF THE INVENTION

[30] The following will describe some embodiments of the present invention, by way of example only, with reference to the drawings. In the drawings, like reference numerals and symbols refer to like elements or equivalents.

[31] In the following paragraphs, some exemplary embodiments are explained with reference to a base station and a terminal for establishing a RACH procedure in a 5G NR communication system. The 5G NR communication system may be a standalone NR system. A standalone NR system may operate on a licensed carrier, an unlicensed carrier, or both a licensed carrier and an unlicensed carrier. The RACH procedure is triggered by events such as an initial access procedure from a user equipment (interchangeably referred to as a UE or a terminal) in a state in which the terminal is powered on but does not have a Radio Resource Control (RRC) connection established (i.e., RRC_IDLE ), RRC reconnection procedure, handover procedure, beam loss recovery, etc. The RACH procedure is either contention-based or contention-free. is essentially a two-step procedure.

[32] FIG. 1 depicts signal flow in accordance with an exemplary method 100 involving a four-way RACH procedure between base station 102 and terminal 104.

[33] In the exemplary method 100 of FIG. 1 base station 102 is a ngNodeB (gNB). It will be appreciated by those skilled in the art that base station 102 may also be an ng-eNB, which is a node providing Evolved Universal Mobile Telecommunications user plane and control plane protocol outputs (Terrestrial Radio Access, E-UTRA). System, UMTS) towards the terminal, and connected via the NG interface to the 5GC.

[34] As shown in FIG. 1, at step 106, the base station 102 periodically transmits synchronization signal blocks (SSBs) and the remaining minimum system information (Remaining Minimum System Information, RMSI) to the terminal 104. The RMSI contains PRACH configuration information (interchangeably referred to as PRACH configuration information), which is determined base station 102. The PRACH configuration contains time and frequency resources that define respective ROs in the frequency and time domains for terminals that are configured to communicate with base station 102, including terminal 104, to establish appropriate RACH procedures with base station 102. Each of the SSBs transmitted from base station 102 to terminal 104 is associated with one or more ROs. Accordingly, at step 106, terminal 104 receives these SSBs and RMSIs from base station 102.

[35] In step 108, the terminal 104 transmits the random access preamble (interchangeably referred to as the PRACH preamble, shown as MSG1) in the RO to the base station 102. The RO is associated with an SSB that is selected/detected due to good quality by the terminal 104 among the SSBs transmitted in step 106. In an embodiment, another terminal may randomly transmit the same PRACH preamble in this RO or another RO associated with the same SSB as this RO (shown in step 108). Accordingly, in step 108, base station 102 receives MSG1 in RO from terminal 104. Base station 102 may also receive the same MSG1 in this RO or another RO associated with the same SSB with an RO from another terminal.

[36] At step 110, the base station 102 is configured to transmit a random access response (shown as MSG2) during a random access response (Random Access Response, RAR) window in response to receiving the PRACH preamble(s) from the terminal 104 and/ or another terminal. The RAR window configuration is determined by the base station and included in the system information. MSG2 contains the index of the PRACH preamble received by base station 102, an advance command, and an uplink grant for scheduled transmission (shown as MSG3). Accordingly, at step 110, terminal 104 is also configured to receive MSG2 during the RAR window in response to transmitting MSG1 to base station 102.

[37] In step 112, if the index of the PRACH preamble transmitted by the terminal 104 in step 108 matches the index of the PRACH preamble received by the base station 102 in MSG2, the terminal 104 is also configured to transmit MSG3, when granting uplink, to the base station 102 in response to receiving MSG2 from base station 102. Otherwise, terminal 104 determines the RACH procedure between terminal 104 and base station 102 as unsuccessful and may restart another RACH procedure. MSG3 contains the identifier of terminal 104. In an embodiment, another terminal with a transmitted PRACH preamble index that matches the PRACH preamble index in MSG2 may also transmit MSG3, in an uplink grant, to base station 102. Accordingly, in step 112, base station 102 configured to receive one or more MSG3s, in an uplink grant, from terminal 104 and/or another terminal in response to a transmission of MSG2.

[38] At step 114, base station 102 is configured to transmit contention resolution (shown as MSG4) in response to receiving one or more MSG3 from terminal 104 and/or another terminal. MSG4 contains the ID of the terminal that won the competition. Accordingly, at step 114, terminal 104 is configured to receive MSG4 from base station 102 in response to transmitting MSG3 to base station 102. If the identifier of terminal 104 matches the identifier of the winning terminal in MSG4, terminal 104 determines a RACH procedure between terminal 104 and base station 102 as successful. Otherwise, the terminal 104 determines the RACH procedure between the terminal 104 and the base station 102 as unsuccessful and may restart another RACH procedure.

[39] Steps 108, 110, 112, and 114 of exemplary method 100 described above form a 4-step RACH procedure. As shown in FIG. 1, before the 4-step RACH procedure, the base station 102 determines the ROs and notifies them to the terminal 104 in the PRACH configuration information transmitted in the RMSI in step 106.

[40] According to the present invention, when the 5G NR communication system operates on an unlicensed carrier, the carrier may have a bandwidth that is a multiple of 20 MHz. The carrier frequency band may be divided into one or more frequency bands. Each frequency section is equal to a frequency sub-band in which the LBT procedure (interchangeably referred to as the LBT sub-band) is performed. The LBT frequency slice or subband may be 20 MHz.

[41] In the 4-step RACH procedure shown in FIG. 1, before transmitting an MSG1 or MSG3 message, terminal 104 may need to perform an LBT procedure to determine if the subband in which MSG1 or MSG3 will be transmitted is idle. If the subband is considered pending (ie, LBT successful), terminal 104 transmits MSG1 or MSG3. If the subband is considered busy (ie, LBT fails), terminal 104 does not transmit MSG1 or MSG3. Similarly, base station 102 may also need to perform an LBT procedure before transmitting MSG2 or MSG4. Reducing the transmission opportunities of MSG1, MSG2, MSG3 and MSG4 due to LBT failures at terminal 104 or base station 102 will degrade the performance of the 4-way RACH procedure. Therefore, mechanisms need to be developed to increase the transmission capacity of MSG1, MSG2, MSG3, and MSG4 in the face of LBT failures in the 4-stage RACH procedure. For example, to improve the transmission capabilities of MSG1 in the case of a carrier containing more than one frequency slice, more than one RO in more than one frequency slice can be allocated to transmit the PRACH preamble at a given time. At this point in time, terminal 104 may simultaneously perform multiple LBT procedures on multiple subbands. Even if one of the plurality of LBT procedures fails, another of the plurality of LBT procedures may succeed. Thus, the opportunities for MSG1 transmission in the face of LBT failures are multiplied.

[42] More than one RO allocated to more than one frequency slot may be used to transmit a PRACH preamble to establish a single RACH procedure, or alternatively may be used to transmit other PRACH preambles to establish a multiple RACH procedure on a carrier. .

[43] In FIG. 2a shows an example of ROs defined in the time and frequency domains and used to transmit MSG1 in a 4-round RACH procedure on an unlicensed carrier having more than one frequency slot, as shown in FIG. 1. In this example, the ROs are spread over more than one frequency section and are used to establish a single RACH procedure.

[44] As shown in FIG. 2a, the carrier frequency band is divided into two frequency sections: a first frequency section and a second frequency section. It is understood that the number of frequency segments per carrier depends on the carrier bandwidth and the size of the LBT subband. For example, if the carrier has a bandwidth of 80 MHz and the LBT subband has a size of 20 MHz, then there are four frequency sections on the carrier. If the carrier has a bandwidth of 80 MHz and the LBT subband has a size of 40 MHz, then there are two frequency sections on the carrier.

[45] In the example shown in FIG. 2a, two ROs are currently available to perform PRACH preamble transmission by the terminal. For example, at time t1, two ROs, such as RO1 and RO2, are available for the terminal to transmit the PRACH preamble to the base station, which are respectively located in the first frequency section and the second frequency section.

[46] In the single RACH procedure, only one PRACH preamble is transmitted. In this regard, the terminal selects RO1 and RO2 located in the first frequency section and the second frequency section, which are both available for PRACH preamble transmission at time t1, and performs the LBT procedure in each frequency section/subband. If the LBT procedure is successful in both frequency segments, the terminal may randomly select one RO from RO1 and RO2 and transmit the PRACH preamble in that RO. In the example in FIG. 2a, the LBT procedure in the first frequency region is successful, while the LBT procedure in the second frequency region fails. Therefore, the terminal transmits the PRACH preamble (ie, MSG1) to the base station at RO1.

[47] After receiving the PRACH preamble from the terminal, the base station returns a random access response (i.e., MSG2 shown in FIG. 1) during the RAR window in one of the two frequency intervals with successful LBT (e.g., in the second frequency interval, as shown in Fig. 2a). The RAR window configuration is determined by the base station and indicated in the system information so that the terminal is aware of a possible RAR window and is ready to receive a random access response. MSG2 may contain more than one scheduled transmission uplink grant (ie, MSG3) in the first frequency section or the second frequency section or both. In the example in FIG. 2a MSG2 comprises an uplink grant to UG1 in a first frequency span and an uplink grant to UG2 in a second frequency span.

[48] When receiving MSG2 at the terminal, the terminal may perform an LBT procedure at time t2 on each frequency slice/subband containing uplink grants for transmitting MSG3. In the example in FIG. 2a, the LBT procedure in the second frequency region is successful, while the LBT procedure in the first frequency region fails. Therefore, the terminal transmits MSG3 to the base station on the uplink grant UG2.

[49] In response to MSG3, the base station sends a contention resolution (i.e., MSG4) on the downlink assignment in one of the two frequency spans with successful LBT (eg, in the first frequency span, as shown in FIG. 2a) to the terminal 104 to complete the 4-step RACH procedure. The downlink assignment is set by the base station and indicated in the Downlink Control Information (DCI) so that the terminal is aware of the possible downlink assignments and is ready to receive contention resolution.

[50] FIG. 2b shows another example of ROs defined in the time and frequency domains and used to transmit MSG1 in a 4-round RACH procedure on an unlicensed carrier having more than one frequency slot. In the example shown in FIG. 2b, ROs are distributed over more than one frequency section and are used to establish a multiple RACH procedure.

[51] Similarly, FIG. 2a, the frequency range of the carrier in FIG. 2b is divided into two frequency regions: a first frequency region and a second frequency region. It is understood that the number of frequency segments per carrier depends on the carrier bandwidth and the size of the LBT subband. For example, if the carrier has a bandwidth of 80 MHz and the LBT subband has a size of 20 MHz, then there are four frequency sections on the carrier.

[52] In the example shown in FIG. 2b, two ROs are currently available to perform PRACH preamble transmission by the terminal. For example, at time t1, RO1 and RO2, which are respectively located in the first frequency section and the second frequency section, are available for the terminal to transmit other PRACH preambles to the base station to establish a plurality of RACH procedures in parallel. It is understood that if the carrier has more frequency spans, the terminal may be able to transmit more PRACH preambles at a time.

[53] In the multiple RACH procedure in FIG. 2b, at time t1, the terminal selects RO1 and RO2 located in the first frequency section and the second frequency section, which are both available for PRACH preamble transmission, and performs the LBT procedure in each frequency section.

[54] In the example of FIG. 2b LBT procedures in both frequency sections are both successful. Therefore, the terminal may send different PRACH preambles (ie, MSG1a and MSG1b) to the base station in RO1 and RO2, respectively, to establish two parallel RACH procedures.

[55] It is understood that the multiple RACH procedure may still occur even if the LBT procedure may not be successful in all frequency regions. For example, if the carrier has more than two frequency segments (e.g., three frequency segments) and the LBT procedure is successful in some (i.e., two) frequency segments, the terminal may send different PRACH preambles in the RO in the frequency segments with successful LBT to establish multiple RACH procedures.

[56] After receiving different PRACH preambles at RO1 and RO2 from the terminal, the base station returns two random access responses (i.e., MSG2a and MSG2b) during the RAR window in the first LBT successful frequency region or in the second LBT successful frequency region. . Alternatively, if LBT is successful in both frequency segments, as shown in FIG. 2b, the base station returns MSG2a and MSG2b, respectively, during the RAR window in each of both frequency regions. The RAR window configuration is determined by the base station and indicated in the system information so that the terminal is aware of the possible RAR windows and is ready to receive random access responses. MSG2a in response to MSG1a contains one or more uplink grants for the scheduled transmission of MSG3a in the first frequency section or the second frequency section or both. MSG2b in response to MSG1b contains one or more uplink grants for the scheduled transmission of MSG3b in the first frequency section or the second frequency section or both. In the example in FIG. 2b, MSG2a comprises an uplink grant to UG1 to transmit MSG3a in the first frequency span, while MSG2b comprises an uplink grant to UG2 to transmit MSG3b in the second frequency span.

[57] When receiving MSG2a and MSG2b at the terminal, the terminal may perform an LBT procedure at time t2 on each frequency slice/subband containing uplink grants for the transmissions of MSG3a and MSG3b. In the example in FIG. 2b LBT procedures in both frequency sections are both successful. Therefore, the terminal transmits MSG3a and MSG3b to the base station on UG1 and UG2, respectively.

[58] After receiving MSG3a and MSG3b from the terminal, the base station returns two resolutions (i.e., MSG4a and MSG4b) when assigning a downlink in the first LBT successful frequency region or in the second LBT successful frequency region. Alternatively, if LBT succeeds on both frequency sections, the base station returns MSG4a and MSG4b, respectively, when assigning a downlink on each of both frequency sections. The downlink assignments are determined by the base station and indicated in the DCI so that the terminal is aware of the possible downlink assignments and is ready to receive contention resolutions. In the example in FIG. 2b, the base station transmits MSG4a when assigning a downlink in the first frequency section and MSG4b when assigning a downlink in the second frequency section.

[59] By dividing the frequency band of the carrier into multiple frequency sections, the ROs are distributed to different frequency sections on the carrier, which in turn significantly improves the transmission capabilities of MSG1 against LBT failures in the single RACH procedure or in the multiple RACH procedure.

[60] As described above, ROs are determined by the base station in terms of time and frequency resources in the PRACH configuration for terminals to establish appropriate RACH procedures with the base station. As shown in FIG. 1, in step 102, PRACH configuration information (interchangeably referred to as PRACH configuration information) is transmitted in the RMSI from the base station to the terminal.

[61] In FIG. 3a shows an example of a PRACH configuration on a licensed carrier according to NR technology, in which the PRACH is configured for each carrier.

), длительность каждого RO и т. д. В примере на Фиг. 3a,

равно 2, а временные позиции слотов PRACH соответственно указывают четыре слота PRACH в конфигурации PRACH, т. е. слот 0 PRACH, слот 1 PRACH, слот 2 PRACH и слот 3 PRACH. [62] Temporary resources for ROs are interchangeably referred to as PRACH temporary resources. In RMSI, temporary PRACH resources are indicated by a parameter in accordance with higher layer protocols. For example, the parameter could be prach-ConfigurationIndex , which specifies the preamble format, PRACH slot time positions, number of time division multiplexed ROs in a PRACH slot (i.e.,

), the duration of each RO, etc. In the example of FIG. 3a,

is 2, and the PRACH slot time positions respectively indicate the four PRACH slots in the PRACH configuration, i.e., PRACH slot 0, PRACH slot 1, PRACH slot 2, and PRACH slot 3.

, частотного ресурса, где

и

равны параметру msg1-FDM в соответствии с протоколами более высокого уровня. Начальную позицию RO в частотной области указывают с помощью параметра msg1-FrequencyStart в соответствии с протоколами более высокого уровня. Мультиплексированные с частотным разделением RO в одном моменте времени нумеруют в порядке возрастания в активной части ширины полосы восходящей линии связи, начиная с самой низкой частоты. [63] Frequency resources for ROs are interchangeably referred to as PRACH frequency resources. The PRACH frequency resources are indicated by a plurality of parameters. Each of the frequency division multiplexed ROs at one point in time has an index

, frequency resource, where

And

are equal to the msg1-FDM parameter according to higher layer protocols. The starting position of the RO in the frequency domain is indicated by the msg1-FrequencyStart parameter in accordance with the higher layer protocols. The frequency division multiplexed ROs at one point in time are numbered in ascending order in the active portion of the uplink bandwidth, starting from the lowest frequency.

[64] The mapping of SSB to RO is shown in the PRACH configuration in FIG. 3a. SSB to RO mapping may be interchangeably referred to as SSB to RO mapping or SSB to RO mapping. The SSB to RO mapping has a period that depends on the PRACH configuration period and the number of SSBs actually transmitted on the carrier.

[65] If the SSB-perRACH-Occasion parameter according to higher layer protocols has a value that is less than one, one SSB is mapped to 1/ SSB-perRACH-Occasion consecutive ROs. For example, as shown in FIG. 3a, the SSB-perRACH-Occasion parameter is set to 1/4. Accordingly, in the example of FIG. 3a one SSB is mapped to 4 consecutive ROs.

[66] In accordance with the mapping of SSB to RO shown in FIG. 3a, the SSB indices are mapped to the RO in the following order:

(1) in ascending order of frequency resource indices for frequency division multiplexed ROs;

(2) in ascending order of the time resource indices for the time division multiplexed ROs in the PRACH slot; And

(3) in ascending order of PRACH slot indices.

[67] FIG. 3b shows a scenario in which the ROs are underutilized when the PRACH configuration according to the NR technology shown in FIG. 3a is used on an unlicensed carrier.

[68] As described above, an unlicensed carrier may contain one or more frequency sections depending on the bandwidth of the carrier and the size of the LBT subband. If a carrier has more than one frequency slice, some ROs may be allocated at the junction of two adjacent carrier frequency slices. If the LBT fails in one of the two adjacent frequency segments at a time, then the RO that corresponds to that time and is allocated at the junction of the two adjacent frequency segments cannot be used to transmit the PRACH preamble.

[69] In the example of FIG. 3b, the carrier has two frequency regions, ie a first frequency region and a second frequency region. ROs circled in dotted lines in FIG. 3b are highlighted at the junction of the first frequency region and the second frequency region. If the LBT fails in the first frequency segment or the second frequency segment at time t1, then the RO shaded with lines cannot be used.

[70] In view of the above, it can be seen that when using the PRACH configuration in accordance with NR technology on an unlicensed carrier, technical problems may arise.

[71] The present invention provides the communication devices and methods shown in the embodiments of FIG. 4a, 4b, 5, 6, 7a-7e, 8 and 9, which are aimed at improving the transmission capabilities of MSG1 against LBT failures in RACH procedures on an unlicensed carrier, as shown in FIG. 2a, 2b and 3b.

[72] In FIG. 4a shows a schematic partial sectional view of a base station 400 that may be used to establish a RACH procedure with a terminal in accordance with the present invention. Similarly, in FIG. 4b shows a schematic partial sectional view of a terminal 450 that may be used to establish a RACH procedure with the base station shown in FIG. 4a according to the present invention.

[73] The various functions and operations of base station 400 and terminal 450 are organized into layers according to a hierarchical model. In this model, lower layers report to and receive instructions from upper layers in accordance with 3GPP 5G NR specifications. For simplicity, the details of the hierarchical model are not discussed in the present description.

[74] As shown in FIG. 4a, base station 400 is typically provided with at least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, at least one antenna 412, and at least one controller 410 to perform, by means of software and hardware, the tasks it is capable of performing, including controlling access to terminals such as terminal 450 shown in FIG. 4b and communicate with them. Data processing, storage, and other related controls may be provided on an appropriate printed circuit board and/or in chipsets. In various implementations, at least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, and at least one antenna 412 may be controlled during operation by at least at least one controller 410.

[75] Similarly, as shown in FIG. 4b, terminal 450 is typically provided with at least one radio receiver 454, at least one radio transmitter 452, at least one transmit signal generator 456, at least one receive signal processor 458, at least one antenna 462, and at least one controller. 460 to perform, by software and hardware, the tasks it is capable of performing, including controlling access to base stations, such as base station 400 shown in FIG. 4A and exchanging data through them. Data processing, storage, and other related controls may be provided on an appropriate printed circuit board and/or in chipsets. In various embodiments, at least one radio transmitter 452, at least one radio receiver 454, at least one transmit signal generator 456, at least one receive signal processor 458, and at least one antenna 462 may be controlled during operation by at least at least one 460 controller.

[76] At least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, and at least one controller 410 of base station 400, and at least one radio transmitter 452, at least one radio receiver 454, at least one transmit signal generator 456, at least one receive signal processor 458, and at least one controller 460 of terminal 450 during operation provide the functions required to establish a RACH procedure between terminal 450 and base station 400 in accordance with embodiments of the present invention.

[77] As described above with reference to FIG. 1, before the 4-way RACH procedure, at least one radio receiver 402 of base station 400 transmits an SSB with an RMSI containing a PRACH configuration to at least one radio receiver 454 of terminal 450. Each of the SSBs is associated with a plurality of ROs.

[78] In the single RACH procedure, after receiving the SSB with RMSI from the base station, the controller 456 of the terminal 450 selects one good quality SSB among SSBs and transmits a PRACH preamble in the form of MSG1 in the RO associated with the selected/detected SSB to at least one radio receiver 404 base station 400.

[79] In the multiple RACH procedure, after receiving the SSB with RMSI from the base station, the controller 456 of the terminal 450 selects one good quality SSB among the SSBs and transmits different PRACH preambles as MSG1 in the plurality of ROs associated with the selected/detected SSB to at least one radio receiver 404 of base station 400.

[80] Based on the PRACH configuration information included in the RMSI received from the base station 400, the controller 456 of the terminal 450 can determine the set of ROs associated with the selected/detected SSB. The set of ROs associated with the selected/discovered SSB is considered as the set of potential ROs.

[81] In the single RACH procedure, the terminal 450 performs an LBT procedure in each frequency section containing a plurality of candidate ROs, and selects an RO in the LBT successful frequency region among the plurality of candidate ROs to establish a single RACH procedure.

[82] Similarly, in the multiple RACH procedure, the terminal 450 performs an LBT procedure in each frequency slot containing a plurality of candidate ROs, and selects a plurality of ROs in one or more successful LBT frequency segments among the plurality of candidate ROs to establish a multiple RACH procedure.

[83] As described above, a carrier frequency band may be divided into more than one frequency portion depending on the carrier bandwidth and LBT subband size. Accordingly, many potential ROs may be distributed over more than one frequency region.

[84] As described above, not all LBT procedures will be successful. Therefore, ROs in the LBT failure portion cannot be used to transmit the PRACH preamble. However, ROs in the other frequency segment with successful LBT in a set of potential ROs remain available for selection by terminal 450 for transmitting the PRACH preamble. As a result, the possibility of transmitting MSG1 within the RACH procedure is increased.

[85] In order to achieve a more efficient RACH procedure, the present invention proposes technical solutions for maximizing RO availability in the event of LBT failure in any frequency region. The technical solutions are shown as examples in FIG. 5, 6, 7a, 7b, 7c, 7d and 7e.

[86] FIG. 5 shows an example of a PRACH configuration to maximize RO availability within an unlicensed carrier RACH procedure in accordance with various embodiments of the present invention.

[87] As shown in the example, the frequency range of the carrier is divided into more than one frequency section. There are two frequency sections on the carrier: a first frequency section and a second frequency section, shown in FIG. 5.

[88] In this example, each of more than one frequency segment is equal to an LBT subband. For example, each of the first frequency section and the second frequency section shown in FIG. 5 are 20 MHz in size if the LBT subband is 20 MHz.

[89] To maximize RO availability, PRACH is configured for each frequency section on a carrier rather than per carrier. That is, each frequency domain configured with PRACH contains ROs that correspond to all SSBs transmitted from base station 400. The advantage is that in this way, even if terminal 450 encounters an LBT failure in the frequency section, resulting in uselessness of ROs corresponding to the selected/detected SSB in that frequency section, terminal 450 can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency sections to transmit the PRACH preamble(s).

[90] In addition, in this example, the selected/detected SSB may be transmitted from the base station 400 to the terminal 450 in only one frequency section of one or more frequency sections. In an alternative implementation, the selected/detected SSB may be transmitted from base station 400 to terminal 450 on more than one frequency slice from one or more frequency slices. To maximize the availability of ROs in either of these two scenarios, a set of potential ROs associated with a selected/discovered SSB is distributed over a set of one or more frequency slots such that the set of one or more frequency slots contains ROs that match the selected/detected SSB. discovered SSB.

[91] The advantage is that by configuring the PRACH to maximize RO availability as shown in FIG. 5 (and also in FIGS. 6, 7a, 7b, 7c, 7d, and 7e), MSG1 transmission opportunities in the face of LBT failure are increased and RACH procedures can be more efficient.

[92] In the example shown in FIG. 5, the PRACH configuration for each frequency section that is configured with PRACH may contain parameters according to higher layer protocols such as prach-ConfigurationIndex , msg1-FrequencyStart , msg1-FDM , etc.

[93] In some examples, one or more parameters in the PRACH configuration may be different in one or more frequency sections. That is, one or more parameters in the PRACH configuration may have a different value for each of the one or more frequency sections. For example, as shown in FIG. 5, the parameter msg1-FrequencyStart , which defines the start position of the RO in the frequency domain, may have a different value, such as msg1-FrequencyStart1 and msg1-FrequencyStart2 , for different frequency sections, for example, the first frequency section and the second frequency section.

мультиплексированных с временным разделением RO в слоте PRACH, может быть одним и тем же, например, имеющим значение 2, на разных участках частот, например на первом участке частот и втором участке частот. Преимуществом является то, что один или более параметров, которые являются общими на одном или более участках частот, облегчают процедуру с одинарным RACH или процедуру с множественным RACH на нескольких участках частот. [94] In some examples, one or more parameters in the PRACH configuration may be common in one or more frequency sections. That is, one or more parameters in a PRACH configuration may have the same value for each of the one or more frequency sections. For example, as shown in FIG. 5, the parameter msg1-FDM , which indicates the number of ROs frequency division multiplexed at one point in time, may be the same, for example, having a value of M equal to 2, in different frequency sections, for example, in the first frequency section and the second frequency section. frequencies. In addition, the prach-ConfigurationIndex parameter, which contains an indication of the number

time division multiplexed RO in a PRACH slot may be the same, eg, having a value of 2, in different frequency sections, eg, the first frequency section and the second frequency section. It is advantageous that one or more parameters that are common in one or more frequency sections facilitate a single RACH procedure or a multiple RACH procedure over multiple frequency regions.

[95] In the example shown in FIG. 5, each frequency span on a carrier (ie, the first frequency span and the second frequency span) is configured with a PRACH. However, those skilled in the art will appreciate that, in some alternative examples, the PRACH may not be configured on every frequency span on a carrier. In other words, it is possible that some of all frequency sections are configured with PRACH.

[96] In these alternative examples, a parameter according to higher layer protocols can be used to indicate and identify those frequency sections that are configured with PRACH among all frequency sections on the carrier. If only one frequency section is configured with the PRACH, this means that the single RACH procedure or the multiple RACH procedure on multiple frequency sections is prohibited.

[97] FIG. 6 depicts an implementation of the PRACH configuration shown in FIG. 5. In this PRACH configuration embodiment, synchronization signal block (SSB) to RO association (which is interchangeably referred to as SSB to RO mapping or SSB to RO mapping) is performed respectively for each of one or more frequency spans that are configured with PRACH.

Таким образом, каждый SSB сопоставляют множеству RO, например, 4 RO, как показано в качестве примера на Фиг 6. [98] As shown in FIG. 6, to maximize RO availability, the value of SSB-perRACH-Occasion is set to less than one, for example

Thus, each SSB is mapped to a set of ROs, for example 4 ROs, as shown by way of example in FIG. 6.

[99] In the embodiment of FIG. 6, the mapping of SSB to RO is performed independently for each of the one or more frequency sections that are configured with PRACH. In each of the one or more frequency spans, ROs associated with the same SSB are at least time multiplexed in a PRACH slot and/or distributed across PRACH slots.

[100] Due to this mapping of SSB to RO, it is possible to perform a single RACH procedure or a multiple RACH procedure with multiple LBT procedures in the time or frequency domain. Thus, even if terminal 450 encounters an LBT failure in a frequency segment, resulting in the uselessness of ROs corresponding to the selected/detected SSB in that frequency segment, terminal 450 can still find ROs corresponding to the same selected/detected SSB with success ( th) LBT on other frequency sections, to transmit the PRACH preamble(s).

[101] For example, terminal 450 may select multiple ROs associated with the detected SSB for transmitting a PRACH preamble in a single RACH procedure or for transmitting multiple PRACH preambles in a multiple RACH procedure.

[102] In a single RACH or multiple RACH procedure, terminal 450 may select a plurality of ROs based on the following options:

Option 1 : Selection of multiple ROs in the same frequency span to provide a single RACH procedure or multiple RACH with multiple LBT procedures in the time domain.

Option 2 : Selection of multiple ROs corresponding to the same time point in different frequency domains to provide a single RACH or multiple RACH procedure with multiple LBT procedures in the frequency domain.

Option 3 : Selection of multiple ROs corresponding to different times in different frequency domains to provide single RACH or multiple RACH procedure with multiple LBT procedures in both time domain and frequency domain.

[103] In the single RACH procedure, in the event of LBT success in one or more frequency spans containing more than one RO, terminal 450 will randomly select an RO from more than one RO and transmit a PRACH preamble in that RO to base station 400 to establish a single RO procedure. RACH. In other words, in the single RACH procedure, one PRACH preamble is transmitted.

[104] In the multiple RACH procedure, in the event of LBT success on one or more frequency spans containing more than one RO, terminal 450 will randomly select at least two ROs from more than one RO and transmit different PRACH preambles in at least two ROs. , which correspond to different RACH procedures in the multiple RACH procedure.

[105] In each of FIGS. 7a, 7b, 7c, 7d and 7e show an implementation of the PRACH configuration shown in FIG. 5. Each of these implementations correspond to SSB to RO mapping/SSB to RO mapping/SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH.

Таким образом, каждый SSB сопоставляют множеству RO, например, 4 RO, как показано в качестве примера на Фиг. 7a, 7b, 7c, 7d и 7e.[106] Similarly, FIG. 6 to maximize RO availability, in the embodiments of FIG. 7a, 7b, 7c, 7d and 7e set the value of SSB-perRACH-Occasion to less than one, for example

Thus, each SSB is mapped to a set of ROs, eg 4 ROs, as shown by way of example in FIG. 7a, 7b, 7c, 7d and 7e.

[107] In the above embodiments , the SSB-perRACH-Occasion parameter may be defined for each carrier. In this scenario, the number of ROs associated with SSB per frequency region is the reciprocal of SSB-per-RACH-Occasion divided by the number of frequency segments configured with PRACH on the carrier.

[108] In an alternative implementation , the SSB-perRACH-Occasion parameter may be determined for each frequency section. In this scenario, the number of ROs associated with SSB per carrier is inverse to the value of SSB-per-RACH-Occasion multiplied by the number of frequency slots configured with PRACH on the carrier.

[109] In the examples shown in FIG. 7a, 7b, 7c, 7d, and 7e, the assignment of SSB to RO is performed on a plurality of frequency sections that are configured with PRACH, such that ROs associated with the same SSB are allocated to at least a plurality of frequency sections that are configured with PRACH, and by time points. In order to allocate ROs associated with the same SSB over time points, the ROs may be time division multiplexed in each PRACH slot. Additionally or alternatively, ROs may be allocated to PRACH slots.

[110] Due to the SSB to RO mappings shown in the PRACH configuration implementation examples in FIG. 7a, 7b, 7c, 7d, and 7e, it is possible to perform a single RACH procedure or a multiple RACH procedure with multiple LBT procedures in the time or frequency domain. Advantageously, even if terminal 450 encounters an LBT failure in a frequency segment resulting in the uselessness of ROs corresponding to the selected/detected SSB in that frequency segment, terminal 450 can still find ROs corresponding to the same selected/detected SSB with successful LBT(s) on other frequency sections, to transmit the PRACH preamble(s).

[111] In FIG. 7a shows a first implementation of SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH. In the example shown in FIG. 7a, one SSB is associated with multiple ROs, eg 4 ROs, as described above. In this example, the SSB indices can be mapped to ROs in the following order:

1) in ascending order of indices of frequency sections;

2) in ascending order of time resource indices for time division multiplexed ROs in the PRACH slot;

3) in ascending order of frequency resource indices for frequency division multiplexed ROs and

4) in ascending order of PRACH slot indices.

[112] In this example, the order of the frequency segment indices and the time resource indices may be interchanged.

[113] Due to the first mapping of SSB to RO, even if the terminal 450 encounters an LBT failure in the frequency section (e.g., in the first frequency section), resulting in the uselessness of the RO corresponding to the selected/detected SSB in that frequency section, the terminal 450 still can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency segments (eg, second frequency segment) to transmit the PRACH preamble(s).

[114] In FIG. 7b shows a second implementation of SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH. In the example shown in FIG. 7b, one SSB is associated with multiple ROs, eg 4 ROs, as described above. In this example, the SSB indices can be mapped to ROs in the following order:

1) in ascending order of indices of frequency sections;

2) in ascending order of time resource indices for time division multiplexed ROs in the PRACH slot;

3) in ascending order of PRACH slot indices; And

4) in ascending order of frequency resource indices for frequency division multiplexed ROs.

[115] In this example, the order of the frequency segment indices and the time resource indices may be interchanged.

[116] Due to the second mapping of SSB to RO, even if the terminal 450 encounters an LBT failure in a frequency section (e.g., in the first frequency section), resulting in the uselessness of the RO corresponding to the selected/detected SSB in that frequency section, the terminal 450 still can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency segments (eg, second frequency segment) to transmit the PRACH preamble(s).

[117] In FIG. 7c shows a third implementation of SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH. In the example shown in FIG. 7c, one SSB is associated with multiple ROs, eg 4 ROs, as described above. In this example, the SSB indices can be mapped to ROs in the following order:

1) in ascending order of indices of frequency sections;

2) in ascending order of PRACH slot indices;

3) in ascending order of frequency resource indices for frequency division multiplexed ROs and

4) in ascending order of time resource indices for time division multiplexed ROs.

[118] In this example, the order of the section indices and the PRACH slot indices may be reversed.

[119] Due to the third mapping of SSB to RO, even if the terminal 450 encounters an LBT failure in the frequency section (e.g., in the first frequency section), resulting in the uselessness of the RO corresponding to the selected/detected SSB in that frequency section, the terminal 450 still can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency segments (eg, second frequency segment) to transmit the PRACH preamble(s).

[120] In addition, due to the third SSB to RO mapping, even if terminal 450 encounters an LBT failure in a PRACH slot, it may be more likely to find ROs corresponding to SSBs that are mapped to a PRACH slot in other PRACH slots.

[121] In FIG. 7d shows a fourth implementation of SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH. In the example shown in FIG. 7d, one SSB is associated with multiple ROs, eg 4 ROs, as described above. In this example, the SSB indices can be mapped to ROs in the following order:

1) in ascending order of indices of frequency sections;

2) in ascending order of PRACH slot indices.

3) in ascending order of time resource indices for time division multiplexed ROs;

4) in ascending order of frequency resource indices for frequency division multiplexed ROs;

[122] In this example, the order of the section indices and the PRACH slot indices may be interchanged.

[123] Due to the fourth SSB to RO mapping, even if the terminal 450 encounters an LBT failure in the frequency section (e.g., in the first frequency section), resulting in the uselessness of the RO corresponding to the selected/detected SSB in that frequency section, the terminal 450 still can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency segments (eg, second frequency segment) to transmit the PRACH preamble(s).

[124] In addition, due to the fourth SSB to RO mapping, even if terminal 450 encounters an LBT failure in a PRACH slot, it may have a better chance of finding ROs corresponding to SSBs that are mapped to a PRACH slot in other PRACH slots.

[125] In FIG. 7e shows a fifth implementation of SSB to RO mapping performed on a plurality of frequency sections that are configured with PRACH. In the example shown in FIG. 7e, one SSB is associated with multiple ROs, such as 4 ROs as described above, and with PRACH slot indices over the first through fourth SSB to RO mappings shown in FIG. 7a-7d, an interleaving operation has been applied.

[126] Due to the fifth association of SSB to RO, even if the terminal 450 encounters an LBT failure in the frequency section (e.g., in the first frequency section), resulting in the uselessness of the RO corresponding to the selected/detected SSB in that frequency section, the terminal 450 still can still find ROs corresponding to the same selected/detected SSB with successful LBT in other frequency segments (eg, second frequency segment) to transmit the PRACH preamble(s).

[127] In addition, due to the fifth SSB to RO mapping, even if terminal 450 encounters LBT failure in two or more consecutive PRACH slots, terminal 450 may be more likely to find ROs corresponding to SSBs that are mapped to two or more consecutive PRACH slots. consecutive PRACH slots, in other PRACH slots.

[128] The third, fourth, or fifth SSB to RO mappings are advantageous in cases where an autonomous NR system operating in unlicensed bands (e.g., unlicensed 5 GHz or 6 GHz bands) coexists with a Wi-Fi network in which the data block duration Physical Layer Protocol Data Unit (PPDU) protocol may have more than one or more PRACH slots.

[129] In view of the above five SSB to RO mappings, more than one SSB and RO mapping among these five SSB to RO mappings may be used in the process of establishing a single RACH procedure or a multiple RACH procedure between the base station 400 and the terminal 450 according to various options. implementation of the present invention.

[130] Examples of the above single RACH procedure and multiple RACH procedure according to the PRACH configuration described in FIG. 5, 6, 7a, 7b, 7c, 7d and 7e can be described with reference to FIGS. 4a and 4b.

[131] In some implementations, at least one transmit signal generator 456 of terminal 450 generates a first PRACH preamble during operation. At least one radio transmitter 452 of terminal 450 during operation transmits a first PRACH preamble to base station 400 in a first RO among a plurality of potential ROs. A plurality of potential ROs may be determined by at least one controller 460 of terminal 450 based on the PRACH configuration information received from base station 400. The first RO is assigned in a first frequency span that is equal to the first subband in which the LBT procedure is performed at terminal 450. In other words, the first frequency section has a size that is equal to the size of the first LBT subband. For example, the first frequency slice has a size of 20 MHz if the first LNT subband is 20 MHz.

[132] As described above, in the single RACH procedure, terminal 450 may select a set of ROs among a set of potential ROs for transmitting a PRACH preamble. Similarly, in the multiple RACH procedure, terminal 450 may select a plurality of ROs among a plurality of potential ROs for transmissions of the plurality of PRACH preambles. A plurality of potential ROs are associated with SSBs selected/discovered by terminal 450 among the SSBs received from base station 400.

[133] Therefore, in some examples, terminal 450 needs to select a set of ROs from a set of potential ROs for a single RACH procedure or a multiple RACH procedure.

[134] In these examples, at least one transmit signal generator 456 of terminal 450 may also generate a second PRACH preamble during operation. In these embodiments, at least one radio transmitter 452 of terminal 450 during operation transmits a second PRACH preamble to the base station in a second RO among a plurality of potential ROs. The second RO is assigned in the second frequency section, which is equal to the second subband in which the LBT procedure is performed at the terminal 450. In other words, the second frequency section has a size that is equal to the size of the second LBT subband. For example, the second frequency slice has a size of 20 MHz if the second LNT subband is 20 MHz.

[135] Those skilled in the art will appreciate that, depending on practical needs and network configurations, the at least one transmit signal generator 456 of terminal 450 during operation may also generate more PRACH preambles to be transmitted by at least one radio transmitter 452 of terminal 450 in additional RO. Additional ROs may be assigned in other frequency sections or in the first and/or second frequency sections.

[136] As described above, in the single RACH procedure, in the event of LBT success in one or more frequency bands containing more than one RO, at least one controller 456 of terminal 450 may randomly select an RO from more than one RO and transmit a PRACH preamble in this RO to the base station 400. In other words, in the single RACH procedure, one PRACH preamble is transmitted.

[137] Similarly, in the multiple RACH procedure, in the event of LBT success in one or more frequency spans containing more than one RO, at least one controller 456 of terminal 450 may randomly select at least two ROs from more than one RO and transmit different PRACH preambles in at least two ROs to base station 400 in other RACH procedures of the multiple RACH procedure. Terminal 450 may generate the first PRACH preamble and the second PRACH preamble based on the same sequence or different sequences. When the same sequence is used to generate the first PRACH preamble and the second PRACH preamble, different cyclic shifts are applied to the same sequence.

[138] In some implementations, the PRACH configuration information received by at least one radio receiver 454 of terminal 450 from base station 400 may include a parameter identifying frequency portions that are configured with PRACH. In some examples, the parameter identifies the first frequency span and the second frequency span that are configured for the PRACH. However, it is possible that not every frequency span on a carrier is configured with a PRACH. Therefore, in some alternative examples, the parameter may identify some of the frequency regions of all frequency regions on the carrier as configured with PRACH. For example, the parameter may be a bitmap whose size is equal to the number of frequency slices on the carrier. Each bit of the bitmap indicates whether the corresponding frequency section is configured with PRACH.

[139] In some implementations, the PRACH configuration information received by at least one radio receiver 454 of terminal 450 from base station 400 may include one or more parameters that are common in the first frequency region and the second frequency region. That is, one or more parameters in the PRACH configuration may have the same value for each of the first frequency span and the second frequency span. For example, one or more parameters indicate the number of ROs that are frequency division multiplexed at one time in the first frequency section and the second frequency section, as described with reference to FIG. 5.

[140] In some embodiments, the PRACH configuration information received by at least one radio receiver 454 of terminal 450 from base station 400 may include one or more parameters in the PRACH configuration that differ in the first frequency region and the second frequency region. That is, one or more parameters in the PRACH configuration may have a different value for each of the first frequency span and the second frequency span. For example, one or more parameters indicate the initial position of the RO in the frequency domain in the first frequency region and the second frequency region, as described with reference to FIG. 5.

[141] As described above, a plurality of potential ROs are associated with the SSB selected/discovered by terminal 450 among the SSBs received from base station 400. In some embodiments, the selected/discovered SSB may be transmitted from base station 400 to terminal 450 in one section. frequencies from the first frequency section and the second frequency section. In an alternative implementation, the selected/detected SSB may be transmitted from base station 400 to terminal 450 in both the first frequency span and the second frequency span. To maximize the availability of ROs in either of these two scenarios, the set of potential ROs associated with the selected/discovered SSB is allocated to each of the first frequency region and the second frequency region such that the first frequency region and the second frequency region each contain an RO, that match the selected/discovered SSB.

[142] In some examples, a set of potential ROs is determined based on the mapping of SSB to RO for the first frequency region or the second frequency region, as described with reference to FIG. 6.

[143] In some examples, a set of potential ROs is determined based on the mapping of SSB to RO for the first frequency region and the second frequency region, as described with reference to FIG. 7a, 7b, 7c, 7d and 7e. In these examples, the set of potential ROs associated with SSB are allocated to the first frequency section and the second frequency section and distributed over time points.

[144] In FIG. 8 shows another schematic example of a base station that may be implemented to establish a RACH procedure on an unlicensed carrier in accordance with the various implementations shown in FIG. 5-7e.

[145] In the schematic example of FIG. 8, at least one base station controller 830 may include at least a PRACH configuration determiner 832, a scheduler 834, a message parser 836, and an LBT circuit 838. The PRACH pattern determiner 832 is configured to determine the PRACH pattern on the carrier during operation. The scheduler 834 is configured during operation to schedule transmissions of higher layer messages (eg, MSG2, MSG4) and system information such as RMSI, etc. to the terminals. The scheduler 834 is also configured during operation to generate uplink grants for higher layer message transmissions (eg, MSG3) for terminals. The runtime message parser 836 is configured to parse the received PRACH preamble and higher level messages (eg, MSG3) from the terminals. The LBT circuit 838 is configured to perform LBT procedures during operation, for example, on each frequency section/subband on the carrier.

[146] In the schematic example of FIG. 8, at least one transmit signal generator 810 may include at least a system information generator 812, a message generator 814, an encoder, and a modulator 816. At least one receive signal processor 820 may include at least a demodulator and a decoder or detector 822.

[147] The system information generator 812 during operation is configured to generate system information such as RMSI based on the results from the PRACH configuration determiner 832 and the scheduler 834.

[148] Based on the LBT results provided by the LBT circuit 838, the message generator 814 during operation is configured to generate higher layer messages, such as random access response (MSG2) messages, in response to receiving a PRACH preamble from the terminal, or messages contention resolution (MSG4) in response to receiving scheduled transmission messages (MSG3) from the terminal.

[149] The encoder and modulator 816 during operation is configured to encode and modulate the generated system information received from the system information generator 812, or higher level messages received from the message generator 814.

[150] The demodulator and decoder or detector 822, during operation, is configured to detect PRACH preambles (MSG1) received from terminals, or demodulate and decode higher layer messages (e.g., MSG3) received from terminals, or identify LBT subbands on a carrier. .

[151] In FIG. 9 shows another schematic example of a terminal that may be implemented to establish a RACH procedure on an unlicensed carrier in accordance with the various implementations shown in FIG. 5-7e.

[152] In the schematic example of FIG. 9, at least one terminal controller 930 may include at least a PRACH configuration determiner 932, a beam determiner 934, an RO determiner 936, a message parser 938, and an LBT circuit 940. The PRACH configuration determiner 932 is operationally configured to determine the PRACH configuration information based on the system information received from the base station. The beam finder 934 is operationally configured to determine the best beam/SSB or beam/SSB of good enough quality from the SSBs transmitted from the base station. The RO determiner 936 is operationally configured to determine/select, based on the LBT results provided by the LBT circuit 940, one or more ROs among the set of potential ROs corresponding to the SSB selected by the beam determiner 934. The runtime message parser 938 is configured to parse higher level received messages (eg, MSG2, MSG4) received from the base station. The LBT circuit 940 is configured to perform LBT procedures during operation, for example, on each frequency section/subband with the configured PRACH on the carrier.

[153] In the schematic example in FIG. 9, a transmit signal generator 910 may include at least a PRACH transmit signal generator 912, a message generator 914, an encoder, and a modulator 916, and a receive signal processor 920 may include at least a demodulator and a decoder 922.

[154] The demodulator and decoder 922 is operatively configured to demodulate and decode the received signal (eg, system information or higher level messages) from the base station or identify the LBT subbands on the carrier via at least one radio receiver 904 of the terminal. The decoded system information or higher layer messages are provided to the PRACH configuration determiner 932, beam determiner 934, RO determiner 936, and message parser 938 to perform their respective functions.

[155] The PRACH transmit signal generator 912 is configured during operation to generate a PRACH preamble signal in one or more ROs determined/selected by the RO determiner 936 in the controller 930.

[156] The generator 914 messages during operation is configured to generate messages of a higher level (eg, MSG3).

[157] The encoder and modulator 916 is operationally configured to encode and modulate higher layer generated messages (eg, MSG3) received from the message generator 914 for transmission to the base station via at least one terminal radio transmitter 902.

[158] As described above, embodiments of the present invention provide improved communication systems, communication methods, and communication devices that enable a more efficient RACH procedure with improved MSG1 transmission capabilities against LBT failures on an unlicensed carrier.

[159] The present invention may be implemented in software, hardware, or software in conjunction with hardware. Each functional block used in the description of each embodiment set forth above may be partially or wholly implemented by an LSI such as an integrated circuit, and each process described in each embodiment may be controlled in part or wholly by the same LSI or combination. BIS. The LSI may be formed separately as chips, or a single chip may be formed to contain some or all of the functional blocks. The LSI may have a data input and output connected to it. In this document, the LSI may be referred to as IC (IC), system LSI, super-LSI or ultra-LSI, depending on the differences in the degree of integration. However, the implementation method of the integrated circuit is not limited to LSIs, and may be implemented using a dedicated circuit, a general purpose processor, or a special purpose processor. In addition, an FPGA (Field Programmable Gate Array) can be used, which can be programmed after the LSI is manufactured or reconfigurable processor, in which the connection configuration and settings of the circuit cells located inside the LSI can be changed. The present invention may be implemented as digital processing or analog processing. If future integrated circuit technology replaces LSIs as a result of the development of semiconductor technology or other derivative technology, functional blocks can be integrated using future integrated circuit technology. Biotechnology may also be applied.

[160] The present invention can be implemented by any kind of device, device or system having a communication function, which are called communication devices.

[161] Non-limiting examples of such a communication device include a telephone (e.g., cellular phone, smartphone), tablet, personal computer (PC) (e.g., laptop, desktop computer, netbook), camera (e.g., digital camera/ camcorder), digital player (digital audio/video player), wearable device (e.g. wearable camera, smart watch, tracking device), game console, digital e-book reader, healthcare/medical teleservice device (remote services in healthcare and medical) and a vehicle that provides communication functionality (e.g. car, airplane, ship) and various combinations thereof.

[162] The communication device is not limited to portable or mobile devices, and may also include any kind of device, device, or system that is non-portable or stationary, such as a smart home device (e.g., household appliance, lighting, smart meter, control panel), a vending machine and any other “things” in the Internet of Things (IoT) network.

[163] Communication may include data exchange, for example, via a cellular system, a wireless LAN system, a satellite system, and so on. and their various combinations.

[164] The communication device may include a device, such as a controller or sensor, that is connected to a communication device that performs the communication function described in the present invention. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication device to perform the communication function of the communication device.

[165] Communication devices may also include an infrastructure facility such as a base station, access point, and any other device, device, or system that communicates with or controls devices, such as the devices in the non-limiting examples above.

[166] The person skilled in the art will appreciate that numerous changes and/or modifications may be made to the present invention, as shown in specific embodiments, without departing from the spirit and scope of the present invention, which is described in a broad sense. Therefore, the present embodiments are to be considered in all respects as illustrative and not restrictive.

[167] In accordance with the present invention, various features are provided, such as:

1. Terminal containing:

a circuit that, during operation, generates a first random access preamble; And

a transmitter that, during operation, transmits the first random access preamble to the base station in the first event (RO) of a Physical Random Access Channel (PRACH) among a plurality of candidate ROs, the plurality of candidate ROs being determined based on the PRACH configuration information received from the base station ,

wherein the first RO is assigned to the first frequency section, the first frequency section being equal to the first subband in which the listen-before-transmit (LBT) procedure is performed at the terminal.

2. Terminal in accordance with statement 1, in which

the circuit generates a second random access preamble during operation; A

the transmitter during operation transmits the second random access preamble to the base station in the second RO among the set of potential ROs,

wherein the second RO is assigned in the second frequency section, the second frequency section being equal to the second subband in which the LBT procedure is performed at the terminal.

3. The terminal according to Claim 2, in which the first random access preamble and the second random access preamble are formed from the same sequence.

4. The terminal according to claim 2, in which the first frequency section is the same as the second frequency section.

5. Terminal in accordance with statement 2, in which the first frequency section differs from the second frequency section.

6. The terminal according to claim 2, comprising a receiver that, during operation, receives a parameter contained in the PRACH configuration information, the parameter identifying the first frequency section and the second frequency section that are configured for the PRACH.

7. The terminal according to Claim 2, comprising a receiver that, during operation, receives one or more parameters contained in the PRACH configuration information, where one or more parameters are common in the first frequency section and the second frequency section.

8. The terminal according to statement 7, wherein one or more parameters indicate the number of ROs that are frequency division multiplexed at one time in the first frequency section and the second frequency section.

9. The terminal according to Claim 2, comprising a receiver that, during operation, receives one or more parameters contained in the PRACH configuration information, wherein one or more of the parameters for the first frequency section and the second frequency section are different.

10. The terminal according to claim 9, wherein one or more parameters indicate the initial position of the RO in the frequency domain in the first frequency region or the second frequency region.

11. A terminal according to Claim 1, wherein a plurality of potential ROs are associated with a Synchronization Signal Block (SSB) received from a base station.

12. The terminal according to claim 11, in which the set of potential ROs are determined based on the correlation of ROs with SSB for the first frequency section or the second frequency section.

13. The terminal according to Claim 11, in which the set of potential ROs are determined based on the correlation of ROs with SSB for the first frequency section and the second frequency section, and the set of potential ROs associated with SSB are distributed:

in the first frequency section and the second frequency section and

by points in time.

14. The terminal according to claim 2, in which a plurality of potential ROs are associated with the SSB transmitted on the first frequency section or the second frequency section.

15. Base station, containing:

a scheme that, during operation, defines a PRACH configuration, wherein the PRACH configuration contains a plurality of potential ROs; And

a receiver that, during operation, receives the first random access preamble in the first RO among the set of potential ROs,

wherein the first RO is assigned to the first frequency section, the first frequency section being equal to the first subband in which the LBT procedure is performed at the terminal.

16. The base station in accordance with the statement 15, in which

the receiver during operation receives from the terminal the second random access preamble in the second RO among the set of potential ROs, the second RO being assigned in the second frequency section, the second frequency section being equal to the second subband in which the LBT procedure is performed at the terminal.

17. The base station according to claim 16, in which the first random access preamble and the second random access preamble are formed from the same sequence.

18. The base station according to claim 16, in which the first frequency section is the same as the second frequency section.

19. The base station in accordance with statement 16, in which the first frequency section differs from the second frequency section.

20. The base station according to claim 16, wherein the transmitter during operation transmits a parameter contained in the PRACH configuration information, the parameter identifying the first frequency section and the second frequency section that are configured for the PRACH.

21. The base station according to claim 16, wherein the transmitter during operation transmits one or more parameters in the PRACH configuration information, wherein the one or more parameters are common in the first frequency section and the second frequency section.

22. The base station according to claim 21, wherein one or more parameters indicate the number of ROs that are frequency division multiplexed at one time in the first frequency section and the second frequency section.

23. The base station according to claim 16, wherein the transmitter during operation transmits one or more parameters in the PRACH configuration information, wherein the one or more parameters for the first frequency section and the second frequency section are different.

24. The base station according to claim 23, wherein one or more parameters indicate the initial position of the RO in the frequency domain in the first frequency region or the second frequency region.

25. The base station according to claim 15, in which a plurality of potential ROs are associated with the SSB transmitted to the terminal.

26. The base station according to claim 25, comprising a controller that, during operation, organizes a plurality of potential ROs based on the mapping of ROs to SSB for the first frequency section or the second frequency section.

27. The base station in accordance with Statement 25, comprising a controller that, during operation, organizes a set of potential ROs based on the mapping of ROs to SSB for the first frequency section and the second frequency section, and the set of potential ROs associated with SSB are distributed:

in the first frequency section and the second frequency section and

by points in time.

28. The base station according to claim 11, in which a plurality of potential ROs are associated with the SSB transmitted in the first frequency segment or the second frequency segment.

29. Communication method, including:

generating a first random access preamble at the terminal, and

transmission from the terminal of the first random access preamble to the base station in the first RO among the set of candidate ROs, and the set of candidate ROs is determined based on the PRACH configuration information received from the base station,

wherein the first RO is assigned in the first frequency section, the first frequency section being equal to the first subband in which the LBT procedure is performed at the terminal.

30. Communication method, including:

determining, at the base station, a PRACH configuration, the PRACH configuration comprising a plurality of potential ROs; And

reception at the base station of the first random access preamble in the first RO among the set of potential ROs,

wherein the first RO is assigned in the first frequency section, the first frequency section being equal to the subband in which the LBT procedure is performed at the terminal.

Claims (38)

1. A communication device, comprising: an integrated circuit that, during operation, generates the first random access preamble; And a transmitter that, during operation, transmits a first random access preamble to a base station in a first event (RO) of a physical random access channel (PRACH) among a plurality of potential ROs corresponding to a synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section. 2. The communications apparatus of claim 1, wherein the first PRACH RO and the second PRACH RO are not consecutive in the frequency domain. 3. The communication device according to claim 1, wherein each of the plurality of frequency sections is 20 MHz. 4. The communication device according to claim 1, wherein each of the plurality of frequency sections is equal to a subband in which the LBT procedure is performed at the terminal. 5. The communication apparatus of claim 1, wherein one or more of the parameters included in the PRACH configuration information are common among the plurality of frequency regions. 6. The communications apparatus of claim 1, wherein the plurality of potential ROs are determined based on the PRACH configuration information received from the base station. 7. The communication apparatus of claim 1, wherein the second random access preamble is transmitted to the base station in a second RO among another set of potential ROs corresponding to a different SSB index. 8. The communications apparatus of claim 1, wherein the SSB indices including the SSB index refer to the set of ROs in the order of frequency resource indices, time resource indices, and PRACH slot indices. 9. Communication method performed by a communication device, including: generating a first random access preamble; and transmitting the first random access preamble to the base station in the first event (RO) of the physical random access channel (PRACH) among the plurality of potential ROs corresponding to the synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section. 10. Base station, comprising: a transmitter that, during operation, transmits a block (SSB) of synchronization signals; And a receiver that, during operation, receives a first random access preamble from a communication device in a first event (RO) of a physical random access channel (PRACH) among a plurality of potential ROs corresponding to an SSB synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section. 11. The base station of claim 10, wherein the first PRACH RO and the second PRACH RO are not consecutive in the frequency domain. 12. The base station of claim 10, wherein each of the plurality of frequency sections is 20 MHz. 13. The base station of claim 10, wherein each of the plurality of frequency sections is equal to a subband in which the LBT procedure is performed at the terminal. 14. The base station of claim 10, wherein one or more of the parameters included in the PRACH configuration information are common among the plurality of frequency sections. 15. The base station of claim 10, wherein the set of potential ROs are determined based on the PRACH configuration information received from the base station. 16. The base station of claim 10, wherein the second random access preamble is transmitted to the base station in a second RO among another set of potential ROs corresponding to a different SSB index. 17. The base station of claim 10, wherein the SSB indices including the SSB index refer to the RO set in the order of frequency resource indices, time resource indices, and PRACH slot indices. 18. The communication method performed by the base station, including: transmission block (SSB) synchronization signals; and receiving a first random access preamble from the communication device in a first event (RO) of a physical random access channel (PRACH) among a plurality of potential ROs corresponding to an SSB synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section. 19. An integrated circuit that, during operation, controls: the formation of the first random access preamble; and transmitting the first random access preamble to the base station in the first event (RO) of the physical random access channel (PRACH) among the plurality of potential ROs corresponding to the synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section. 20. An integrated circuit that, during operation, controls: the transmission block (SSB) of synchronization signals; and receiving a first random access preamble from the communication device in a first event (RO) of a physical random access channel (PRACH) among a plurality of potential ROs corresponding to an SSB synchronization signal block (SSB) index; wherein each of the plurality of potential ROs is assigned to any frequency portion of the plurality of frequency portions, wherein the first PRACH RO corresponding to the SSB index is assigned to the first frequency section of the plurality of frequency sections, and the second PRACH RO corresponding to the SSB index is assigned to the second frequency section of the plurality of frequency sections which is different from the first frequency section.

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