Patent Description:
To meet the demand for wireless data traffic having increased since deployment of fourth generation (<NUM>) communication systems, efforts have been made to develop an improved fifth generation (<NUM>) or pre-<NUM> communication system. Therefore, the <NUM> or pre-<NUM> communication system is also called a 'beyond <NUM> network' or a 'post long term evolution (LTE) System'. The <NUM> wireless communication system is considered to be implemented not only in lower frequency bands but also in higher frequency (mmWave) bands, e.g., <NUM> to <NUM> bands, so as to accomplish higher data rates. To mitigate propagation loss of the radio waves and increase the transmission (TX) distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, and large scale antenna techniques are being considered in the design of the <NUM> wireless communication system. In the <NUM> system, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM), frequency QAM (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the internet of things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The internet of everything (IoE), which is a combination of the IoT technology and the big data processing technology through connection with a cloud server, has emerged. As technology elements, such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "Security technology" have been demanded for IoT implementation, a sensor network, a machine-to-machine (M2M) communication, machine type communication (MTC), and so forth have been recently researched.

For example, technologies, such as a sensor network, MTC, and M2M communication may be implemented by beamforming, MIMO, and array antennas.

In the recent years several broadband wireless technologies have been developed to meet the growing number of broadband subscribers and to provide more and better applications and services. The second generation (<NUM>) wireless communication system has been developed to provide voice services while ensuring the mobility of users. Third generation (<NUM>) wireless communication system supports not only the voice service but also data service. The <NUM> wireless communication system has been developed to provide high-speed data service. However, the <NUM> wireless communication system currently suffers from lack of resources to meet the growing demand for high speed data services. Therefore, the <NUM> wireless communication system is being developed to meet the growing demand of various with diverse requirements, e.g. high speed data services, support ultra-reliability and low latency applications.

In addition, the <NUM> wireless communication system is expected to address different use cases having quite different requirements in terms of data rate, latency, reliability, mobility etc. However, it is expected that the design of the air-interface of the <NUM> wireless communication system would be flexible enough to serve the user equipments (UEs) having quite different capabilities depending on the use case and market segment the UE cater service to the end customer. Example use cases the <NUM> wireless communication system wireless system is expected to address is enhanced mobile broadband (eMBB), massive machine type communication (m-MTC), ultra-reliable low latency communication (URLL) etc. The eMBB requirements like tens of Gbps data rate, low latency, high mobility so on and so forth address the market segment representing the conventional wireless broadband subscribers needing internet connectivity everywhere, all the time and on the go. The m-MTC requirements like very high connection density, infrequent data transmission, very long battery life, low mobility address so on and so forth address the market segment representing the IoT/IoE envisioning connectivity of billions of devices. The URLL requirements like very low latency, very high reliability and variable mobility so on and so forth address the market segment representing the industrial automation application, vehicle-to-vehicle/vehicle-to-infrastructure communication foreseen as one of the enabler for autonomous cars.

In the <NUM> (also referred as next generation radio or new radio (NR)) wireless communication system, random access (RA) procedure is used to achieve uplink time synchronization. RA procedure is used during initial access, handover, radio resource control (RRC) connection re-establishment procedure, scheduling request transmission, secondary cell group (SCG) addition/modification, beam failure recovery and data or control information transmission in uplink by non-synchronized UE in RRC CONNECTED state.

<FIG> shows a contention based RA procedure which comprises of <NUM> operations according to the related art. RA preamble (or Msg1) transmission (operation <NUM>): UE selects one of the available contention based RA preambles. The contention based RA preambles can be optionally partitioned into two groups (group A and group B). If two groups are configured and if the potential Msg3 size (UL data available for transmission plus MAC header and, where required, media access control (MAC) control elements (CEs)) is greater than ra-Msg3SizeGroupA and the pathloss is less than PCMAX (of the serving cell performing the RA procedure) - preambleReceivedTargetPower - deltaPreambleMsg3 - messagePowerOffsetGroupB, UE select the RA preambles group B. Otherwise UE select the RA preambles group A. PreambleReceivedTargetPower, messagePowerOffsetGroupB and ra-Msg3 SizeGroupA are configured by network (e.g. gNB).

RA response (RAR) or Msg2 (operation <NUM>): gNB transmits the RAR on physical downlink shared channel (PDSCH) addressed to RA-radio network temporary identifier (RNTI). RA-RNTI identifies the time-frequency resource in which RA preamble was detected by gNB. RAR conveys RA preamble identifier, timing alignment information, temporary cell-RNTI (C-RNTI) and uplink (UL) grant for Msg <NUM>.

Scheduled UL transmission on UL shared channel (SCH) (or Msg3) (operation <NUM>): It is used to transmit message such as RRC connection request, RRC connection re-establishment request, RRC handover confirm, scheduling request, etc. It also includes the UE identity (i.e. C-RNTI or system architecture evolution (SAE)-temporary mobile subscriber identity (S-TMSI) or a random number). Hybrid automatic repeat request (HARQ) is used for this transmission. This is commonly referred as Msg3.

Contention resolution message (operation <NUM>): It uses HARQ and is addressed to C-RNTI (if included in Msg <NUM>) or temporary C-RNTI (UE identity included in Msg3 is included this case). On successful decoding of this message, HARQ feedback is only sent by UE which detects its own UE ID (or C-RNTI).

In NR the size of Msg3 for RRC connection request is <NUM> bits (structure of message: 3bits; UE identity: <NUM> bits; Establishment Cause: <NUM> bits; MAC header: <NUM> bytes). The size of Msg3 is <NUM> byte more than LTE and hence leads to reduced UL coverage. Similarly the size of Msg3 for RRC establishment request also requires <NUM> bits in NR and should be reduced to <NUM> bits. The size of Msg3 for RRC connection resume requires <NUM> bits and should be reduced to <NUM> bits. 3GPP contribution R1-<NUM> discloses details of RACH procedure.

It is known to those skilled in the art that blocks of a flowchart (or sequence diagram) and a combination of flowcharts may be represented and executed by computer program instructions. These computer program instructions may be loaded on a processor of a general purpose computer, special purpose computer, or programmable data processing equipment. When the loaded program instructions are executed by the processor, they create a means for carrying out functions described in the flowchart. Because the computer program instructions may be stored in a computer readable memory that is usable in a specialized computer or a programmable data processing equipment, it is also possible to create articles of manufacture that carry out functions described in the flowchart. Because the computer program instructions may be loaded on a computer or a programmable data processing equipment, when executed as processes, they may carry out operations of functions described in the flowchart.

A block of a flowchart may correspond to a module, a segment, or a code containing one or more executable instructions implementing one or more logical functions, or may correspond to a part thereof. In some cases, functions described by blocks may be executed in an order different from the listed order. For example, two blocks listed in sequence may be executed at the same time or executed in reverse order.

In this description, the words "unit", "module" or the like may refer to a software component or hardware component, such as, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC) capable of carrying out a function or an operation. However, a "unit", or the like, is not limited to hardware or software. A unit, or the like, may be configured so as to reside in an addressable storage medium or to drive one or more processors. Units, or the like, may refer to software components, object-oriented software components, class components, task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays or variables. A function provided by a component and unit may be a combination of smaller components and units, and may be combined with others to compose larger components and units. Components and units may be configured to drive a device or one or more processors in a secure multimedia card.

Prior to the detailed description, terms or definitions necessary to understand the disclosure are described. However, these terms should be construed in a non-limiting way.

The "base station (BS)" is an entity communicating with a user equipment (UE) and may be referred to as BS, base transceiver station (BTS), node B (NB), evolved NB (eNB), access point (AP), fifth generation (<NUM>) NB (5GNB), or next generation NB (gNB).

The "UE" is an entity communicating with a BS and may be referred to as UE, device, mobile station (MS), mobile equipment (ME), or terminal.

In new radio (NR), a <NUM> byte or <NUM> byte media access control (MAC) subheader is added before each MAC service data unit (SDU). The MAC subheader comprises of R, F, logical channel ID (LCID) and L fields.

In one embodiment of the disclosure <NUM> byte MAC subheader is used for MAC SDU if the MAC SDU is a common control channel (CCCH) SDU. Otherwise <NUM> byte or <NUM> byte MAC subheader is used for a MAC SDU. The CCCH SDU can be of multiple sizes (expressed in bits) and <NUM> byte MAC subheader is used for CCCH SDU irrespective of size of CCCH SDU. In one embodiment there can be two sizes (size X and size Y) of CCCH SDU. CCCH SDU of size X and size Y can also be referred as CCCH and CCCH1 SDU respectively. In the description term CCCH is commonly used for both CCCH and CCCH1.

<FIG> shows the operations according to an embodiment of the disclosure.

<FIG> illustrates 2byte R/F/LCID/L MAC subheader according to an embodiment of the disclosure.

<FIG> illustrates 3byte R/F/LCID/L MAC subheader according to an embodiment of the disclosure.

<FIG> illustrates 1byte R/LCID MAC subheader according to an embodiment of the disclosure.

<FIG> shows the UE operations according to an embodiment of the disclosure.

Referring to <FIG>, UE selects one <NUM> byte MAC subheader at operation <NUM>.

Referring to <FIG>, the <NUM> byte MAC subheader may include two <NUM> bit R field and <NUM> bits LCID field. The UE sets R fields in the MAC subheader to zeros at operation <NUM>. In this embodiment, the UE sets the LCID field in the MAC header based on the size of CCCH SDU. Specifically, the UE identifies whether the size of CCCH SDU is M bits at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits, at operation <NUM>. Otherwise, the UE identifies whether the size of CCCH SDU is N bits at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is N bits, at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID Z, if the size of CCCH SDU is other than M and N bits, at operation <NUM>. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits.

In an embodiment, a UE determines whether a MAC SDU is associated with a CCCH or a DCCH. If the MAC SDU corresponds to a CCCH SDU, the UE identifies the size of the MAC SDU to determine a LCID field of MAC subheader. The UE generates a MAC PDU including the MAC subheader and the MAC SDU, and transmits a Msg <NUM> associated with the generated MAC PDU to the gNB.

<FIG> shows the gNB operations according to an embodiment of the disclosure.

Referring to <FIG>, gNB reads the LCID in MAC subheader at operation <NUM>. The gNB identifies whether the LCID is one of the LCIDs (X, Y, Z) reserved for CCCH SDU at operation <NUM>. Based on the value of LCID in the MAC subheader of MAC subPDU, the gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC SDU is not for CCCH, the gNB reads the Length field in the MAC subheader to determine the MAC SDU size at operation <NUM>. If the MAC subPDU is for CCCH, the gNB can know the length of MAC SDU based on LCID value. Specifically, the gNB identifies whether the LCID is equals to X at operation <NUM>. If the LCID is equals to X, the gNB determines that the CCCH SDU size is M bits at operation <NUM>. If the LCID is not equals to X, the gNB identifies whether the LCID is equals to Y at operation <NUM>. If the LCID is equals to Y, the gNB determines that the CCCH SDU size is N bits at operation <NUM>. If the LCID is not equals to X and Y, the gNB determines that the CCCH SDU size is other than M and N bits at operation <NUM>.

In an embodiment, the gNB receives a Msg3 associated with a MAC PDU including a MAC subheader and a MAC SDU from a UE. The LCID in MAC subheader may indicate that the MAC SDU is associated with a CCCH. If the received MAC SDU is a CCCH SDU, the gNB identifies the size of the MAC SDU based on a LCID field of the MAC subheader.

<FIG> shows the UE operations according to an embodiment of the disclosure.

Referring to <FIG>, UE includes one <NUM> byte MAC subheader at operation <NUM>. As shown in <FIG>, the <NUM> byte MAC subheader may include two <NUM> bit R field and <NUM> bits LCID field. The UE sets R fields in the MAC subheader to zeros at operation <NUM>. In this embodiment, the UE sets the LCID field in the MAC header based on the size of CCCH SDU. Specifically, the UE identifies whether the size of CCCH SDU is M bits at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits, at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is N bits, at operation <NUM>. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits. CCCH SDU of size M bits and size N bits can also be referred as CCCH SDU and CCCH1 SDU respectively.

<FIG> shows the gNB operations according to another embodiment of the disclosure.

Referring to <FIG>, gNB reads the LCID in MAC subheader at operation <NUM>. The gNB identifies whether the LCID is one of the LCIDs (X, Y) reserved for CCCH SDU at operation <NUM>. Based on the value of LCID in the MAC subheader of MAC subPDU, the gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC SDU is not for CCCH LCID corresponds to dedicated control or traffic channel, the MAC subheader is a 2B or 3B MAC subheader and the gNB reads the Length field in the MAC subheader to determine the MAC SDU size at operation <NUM>. If the MAC subPDU is for CCCH the gNB can know the length of MAC SDU based on LCID value. Specifically, the gNB identifies whether the LCID is equals to X at operation <NUM>. If the LCID is equals to X, the gNB determines that the CCCH SDU size is M bits at operation <NUM>. If the LCID is not equals to X, i.e., the LCID is equals to Y, the gNB determines that the CCCH SDU size is N bits at operation <NUM>.

<FIG>, UE sets the LCID field in the MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits, at operation <NUM>. UE sets the LCID field in the MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is other than M bits, at operation <NUM>. The value of M is pre-defined in the system. In an example, M can be <NUM> bits. Based on the value of LCID in MAC subheader of MAC subPDU, gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC subPDU is for CCCH it can know the length of MAC SDU based on LCID value.

<FIG> shows the UE operations according to an embodiment of the disclosure.

Referring to <FIG>, UE includes one <NUM> byte MAC subheader at operation <NUM>. As shown in <FIG>, the <NUM> byte MAC subheader may include two <NUM> bit R field and <NUM> bits LCID field. The UE sets first R, i.e. R1 field in the MAC subheader to zeros at operation <NUM>. In this embodiment, the UE sets the LCID field in the MAC header based on the size of CCCH SDU. The UE sets the LCID field in the MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M or N bits. Specifically, the UE identifies whether the size of CCCH SDU is M bits at operation <NUM>. If the size of CCCH SDU is M bits, the UE sets the LCID field in the MAC subheader to a pre-defined LCID X at operation <NUM>, and the UE sets second R field to <NUM> at operation <NUM>. The UE identifies whether the size of CCCH SDU is N bits at operation <NUM>. If the size of CCCH SDU is N bits, the UE sets the LCID field in the MAC subheader to a pre-defined LCID X at operation <NUM>, and the UE sets second R field to <NUM> at operation <NUM>. The UE sets the LCID field in the MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is neither M nor N bits, at operation <NUM>. If the size of CCCH SDU is neither M nor N bits, second R field is set to zero at operation <NUM>. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits.

Referring to <FIG>, gNB reads the LCID in MAC subheader at operation <NUM>. The gNB identifies whether the LCID is one of the LCIDs (X, Y) reserved for CCCH SDU at operation <NUM>. Based on the value of LCID in the MAC subheader of MAC subPDU, the gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC SDU is not for CCCH, and LCID corresponds to dedicated control or traffic channel, the MAC subheader is a 2B or 3B MAC subheader and the gNB reads the Length field in MAC subheader to determine the MAC SDU size at operation <NUM>. If the MAC SDU is for CCCH, the gNB identifies whether the LCID is equals to X at operation <NUM>. If the LCID is not equals to X, the gNB determines that CCCH SDU size is other than M and N bits at operation <NUM>. If the LCID is equals to X, the gNB identifies whether R2 field in MAC subheader is set to <NUM> at operation <NUM>. If the R2 field in the MAC subheader is set to <NUM>, the gNB determines that CCCH SDU size is M bits at operation <NUM>. If the R2 filed in the MAC subheader is not set to <NUM>, the gNB determines that CCCH SDU size is N bits at operation <NUM>.

The UE transmits the generated MAC PDU to the gNB at operation <NUM>.

In an embodiment, UE (i.e. transmitter) determines whether the RRC message to be transmitted is a CCCH message or not. If the RRC message to be transmitted is a CCCH message, the UE includes a MAC subPDU in MAC PDU wherein the MAC subPDU comprises of <NUM> byte R/R/LCID MAC subheader and CCCH message. If the RRC message to be transmitted is a DCCH message, the UE includes a MAC subPDU in MAC PDU wherein the MAC subPDU comprises of 2byte or 3byte R/F/LCID/L MAC subheader and DCCH message.

In an embodiment, gNB (i.e. receiver) determines whether the MAC SDU is a CCCH SDU or not in the received MAC subPDU. If the MAC SDU is a CCCH SDU, MAC subheader in MAC subPDU is a <NUM> byte R/R/LCID MAC subheader. If the MAC SDU is not a CCCH SDU, MAC subheader in MAC subPDU is a <NUM> byte or <NUM> byte R/F/LCID/L MAC subheader.

In an embodiment of the disclosure if size of CCCH SDU is M bits, UE selects one byte MAC subheader for CCCH and sets LCID in MAC subheader to a pre-defined LCID X. If size of CCCH SDU is other than M bits, UE sets LCID in MAC subheader to a pre-defined LCID Y. If CCCH SDU is other than M bits, UE selects <NUM> byte MAC subheader if UL grant size is N bits. If CCCH SDU is other than M bits, UE selects <NUM> byte MAC subheader if UL grant size is greater than N bits. M and N are pre-defined.

In NR, a <NUM> byte or <NUM> byte MAC subheader is added before each MAC SDU. The MAC subheader comprise of R, F, LCID and L fields.

In one embodiment of the disclosure <NUM> byte MAC subheader is used for MAC SDU if the MAC SDU is a CCCH SDU. Otherwise <NUM> byte or <NUM> byte MAC subheader is used for a MAC SDU. The CCCH SDU can be of multiple sizes (expressed in bits) and <NUM> byte MAC subheader is used for CCCH SDU irrespective of size of CCCH SDU. In one embodiment there can be two sizes (size X and size Y) of CCCH SDU. CCCH SDU of size X and size Y can also be referred as CCCH and CCCH1 SDU respectively. In the description term CCCH is commonly used for both CCCH and CCCH1.

<FIG> shows the operations according to Embodiment <NUM> of the disclosure.

In an embodiment of the disclosure (as shown in <FIG>), UE sets the LCID in MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits. UE sets the LCID in MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is N bits. UE sets the LCID in MAC subheader to a pre-defined LCID Z, if the size of CCCH SDU is other than M and N bits. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits. Based on the value of LCID in MAC subheader of MAC subPDU, gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC subPDU is for CCCH the gNB can know the length of MAC SDU based on LCID value. In an embodiment if the size of CCCH SDU is other than M and N bits and if there can be several CCCH SDU sizes other than M and N bits, UE can add <NUM> byte MAC subheader which includes the length field. GNB operations in an embodiment are shown in <FIG>.

In an embodiment of the disclosure (as shown in <FIG>), UE sets the LCID in MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits. UE sets the LCID in MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is N bits. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits. Based on the value of LCID in MAC subheader of MAC subPDU, gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC subPDU is for CCCH, the gNB can know the length of MAC SDU based on LCID value. GNB operations in an embodiment are shown in <FIG>.

In an embodiment of the disclosure (as shown in <FIG>), UE sets the LCID in MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M bits. UE sets the LCID in MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is other than M bits. The value of M is pre-defined in the system. In an example, M can be <NUM> bits. Based on the value of LCID in MAC subheader of MAC subPDU, gNB can know that MAC SDU in MAC subPDU is for CCCH or not. If the MAC subPDU is for CCCH, the gNB can know the length of MAC SDU based on LCID value. GNB operations in an embodiment are shown in <FIG>.

In an embodiment of the disclosure (as shown in <FIG>), UE sets the LCID in MAC subheader to a pre-defined LCID X, if the size of CCCH SDU is M or N bits. If the size of CCCH SDU is M bits, second R field is set to <NUM>. If the size of CCCH SDU is N bits, second R field is set to <NUM>. UE sets the LCID in MAC subheader to a pre-defined LCID Y, if the size of CCCH SDU is neither M nor N bits. If the size of CCCH SDU is neither M nor N bits, second R field is set to zero. The values of M and N are pre-defined in the system. In an example, M can be <NUM> bits and N can be <NUM> bits. GNB operations in an embodiment are shown in Figure <FIG>.

In an embodiment, UE (i.e. transmitter) determines whether the MAC SDU to be transmitted is a CCCH SDU or not. If the MAC SDU to be transmitted is a CCCH SDU, the UE includes a MAC subPDU in MAC PDU wherein the MAC subPDU comprises of <NUM> byte R/R/LCID MAC subheader and MAC SDU. If the MAC SDU to be transmitted is not a CCCH SDU, the UE includes a MAC subPDU in MAC PDU wherein the MAC subPDU comprises of 2byte or 3byte R/F/LCID/L MAC subheader and MAC SDU.

In NR there is an association between synchronization signal (SS) blocks (SSBs) and PRACH preambles/PRACH occasions. This enables gNB to identify the TX beam for transmitting Msg2. This also enables gNB to receive Msg1 using specific RX beam(s) in specific PRACH occasion. So, the RA resource for each SI request needs to be signaled per SSB.

si-Request-Resources can be signaled in SIB1 wherein si-Request-Resources is a list of SI-Request-Resources. si-Request-Resources indicates RA resources for a SI request. Each entry in the list si-Request-Resources contains RA resources corresponding to a SI request. If there is only one entry in the list, the RA resources in this entry are used for all SI messages which are provided on demand. Otherwise RA resources in 1st entry in the list corresponds to first on demand SI message in schedulingInfoList, RA resources in 2nd entry in the list corresponds to second on demand SI message in schedulingInfoList and so on.

There are several options to signal RA resources for a SI request, i.e. to define SI-Request-Resources.

For each SI request, ra-PreambleIndex can be signaled for each SSB explicitly as shown below. See Table <NUM> below. Network (i.e. gNB) signals the same in system information, i.e. SIB1; ra-PreambleIndexList is signaled for each SI request wherein the ra-PreambleIndexList includes SSB index and ra-PreambleIndex. ra-ssb-OccasionMaskIndex is also signaled for each SI request; ra-ssb-OccasionMaskIndex is the index to a pre-defined PRACH mask index table wherein each entry in the table indicates the random access channel (RACH) occasions(s) to be used. Note that ra-ssb-OccasionMaskIndex is not signaled for each SSB. The signaled value of ra-ssb-OccasionMaskIndex is applicable to all SSBs. UE selects a suitable SSB (above a threshold configured by network in system information). UE then selects a preamble corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. UE also selects a RACH occasion (indicated by ra-ssb-OccasionMaskIndex or rach occasion index) corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. If ra-ssb-OccasionMaskIndex is not signaled, UE can select next available RACH occasion from the RACH occasions corresponding to this SSB.

This approach may lead to significant overhead (up to <NUM> + (<NUM>+<NUM>)*<NUM> = <NUM> bits for one SI request configuration, where ra-ssb-OccasionMaskIndex is <NUM> bits, ra-PreambleIndex is <NUM> bits, SSB-Index is <NUM> bits and number of SSBs is <NUM>) because of large number of SSBs (up to <NUM>).

Alternate approach to embodiment <NUM> is to signal a list (ra-PreambleIndexList) of ra-PreambleIndexes for each SI request wherein the SSB Index associated with a ra-PreambleIndex is not signaled; ra-PreambleIndexList is included in SI-Request-Resources. See Table <NUM> below. Network (i.e. gNB) signals the same in system information, i.e. SIB1. If multiple SSBs are mapped to same PRACH occasion, different dedicated PRACH preambles are needed to distinguish these SSBs. If only one SSB is mapped to one PRACH occasion or to multiple PRACH occasions, only one dedicated preamble is needed. So, if the number of SSBs per PRACH occasion is less than or equal to <NUM>, the size of this list is <NUM>. If the number of SSBs per PRACH occasion is less than one, preamble with preamble index = ra-PreambleStartIndex is used for SI request and corresponds to all SSBs. If the number of SSBs per PRACH occasion is larger than or equal to <NUM>, the size of this list is equal to number of SSBs per PRACH occasion and the 'ith' preamble in this list (ra-PreambleIndexList) corresponds to ith SSB among the SSBs associated with a PRACH Occasion. The maximum overhead for one SI request configuration is <NUM>+<NUM>*<NUM> = 100bits where ra-ssb-OccasionMaskIndex is <NUM> bits, RAPreambleIndex is <NUM> bits, maximum number of SSBs per PRACH Occasion is <NUM>.

<FIG> is an example illustration of mapping preambles in ra-PreambleIndexList to SSBs.

In the example <NUM> SSBs are mapped per PRACH occasion and there are <NUM> SSBs. In this case ra-PreambleIndexList incudes four preamble indexes (e.g. P1, P2, P3 and P4). The 'ith' preamble in this list corresponds to ith SSB among the SSBs associated with a PRACH Occasion.

UE selects a suitable SSB (above a threshold configured by network in system information). UE then selects a preamble corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. UE also selects a RACH occasion (indicated by ra-ssb-OccasionMaskIndex or rach occasion index) corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. UE then transmits Msg1 using selected preamble and RACH occasion.

Embodiment <NUM> in an embodiment, instead of signaling a list of ra-PreambleIndexes as explained in embodiment <NUM>, ra-PreambleStartIndex indicating a start index of at least one RA preamble for each SI request can be signaled as shown below. ra-PreambleStartIndex is included in SI-Request-Resources. See Table <NUM> below. Network (i.e. gNB) signals the same in system information, i.e. SIB1. UE can determine the list of ra-PreambleIndexes based on ra-PreambleStartIndex and number of SSBs per RACH Occasion. The number of SSBs per RACH Occasion is also signaled in system information, i.e. SIB1.

Mapping of preambles to SSBs based on ra-PreambleStartIndex (option <NUM>): If the number of SSBs per PRACH occasion is less than one, the preamble with preamble index = ra-PreambleStartIndex is used for SI request. This preamble is used for any SSB selected by UE. If the number of SSBs per PRACH occasion is larger than or equal to <NUM>, PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + number of SSBs per RACH Occasion -<NUM>' are used for this SI request. The 'ith' preamble in this list corresponds to ith SSB among the SSBs associated with a RACH Occasion. In other words, if N SSBs are associated with a RACH occasion, where N > = <NUM>, for the ith SSB (i=<NUM>,. N-<NUM>) mapped to a RACH occasion, preamble with preamble index = ra-PreambleStartIndex + i is used for SI request; For N < <NUM>, the preamble with preamble index = ra-PreambleStartIndex is used for this SI request.

Referring to <FIG>, <FIG> SSBs are mapped per PRACH occasion and there are <NUM> SSBs. Network signals ra-PreambleStartIndex for SI request in SI-Request-Resources. PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + <NUM>' are used for this SI request.

Mapping of preambles to SSBs based on ra-PreambleStartIndex (option <NUM>): If N SSBs are associated with a RACH occasion, where N > = <NUM>, for the ith SSB (i=<NUM>,. N-<NUM>) mapped to a RACH occasion, preamble with preamble index = ra-PreambleStartIndex + i*(<NUM>/N) is used for SI request; For N < <NUM>, the preamble with preamble index = ra-PreambleStartIndex is used for this SI request. In the example of <FIG>, <FIG> SSBs are mapped per PRACH occasion and there are <NUM> SSBs. Network signals ra-PreambleStartIndex for SI request in SI-Request-Resources.

SSB0 to SSB <NUM> are mapped to RO#<NUM>. So P1 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB0, P2 (indicated by ra-PreambleStartIndex+(<NUM>/<NUM>)) corresponds to SSB1, P3 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB2, and P4 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB3.

SSB4 to SSB <NUM> are mapped to RO#<NUM>. So P1 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB4, P2 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB5, P3 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB6, and P4 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB7.

SSB8 to SSB <NUM> are mapped to RO#<NUM>. So P1 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB8, P2 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB9, P3 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB10, and P4 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB11.

SSB12 to SSB <NUM> are mapped to RO#<NUM>. So P1 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB <NUM>, P2 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB <NUM>, P3 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB14, and P4 (indicated by ra-PreambleStartIndex+<NUM>*(<NUM>/<NUM>)) corresponds to SSB15.

UE receives at least one SSB from gNB, and UE selects a suitable SSB (above a threshold configured by network in system information) among the at least one SSB. If none of SSB is suitable, UE may select any SSB. UE then selects a preamble corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. UE also selects a RACH occasion (indicated by ra-ssb-OccasionMaskIndex or rach occasion index) corresponding to this SSB from SI-Request-Resources corresponding to SI message which UE wants to request. If ra-ssb-OccasionMaskIndex is not signaled, UE can select next available RACH occasion from the RACH occasions corresponding to selected SSB. UE then transmits Msg1 using selected preamble and RACH occasion.

In embodiment <NUM>, instead of signaling ra-PreambleStartIndex for each SI request as explained in embodiment <NUM>, ra-PreambleStartIndex can be indicated for on demand SI. UE can determine the list of ra-PreambleIndexes based on ra-PreambleStartIndex, number of SSBs per RACH Occasion and configuration type.

If configuration type is common, this means there is a common configuration for all on Demand SI messages. This can be indicated by signaling configuration type set to 'common'. Alternately, if dedicatedConfig is not included then configuration type is common. In this case Msg1 (i.e. SI request) transmitted by UE does not indicate request for a specific SI message and upon reception of Msg1 network transmits all On-Demand SI messages. In this case if the number of SSBs per PRACH occasion is larger than or equal to <NUM>, PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + number of SSBs per RACH Occasion -<NUM>' are used for SI request. The 'ith' preamble in this list corresponds to ith SSB among the SSBs associated with a RACH Occasion. In the example of <FIG>, <FIG> SSBs are mapped per PRACH occasion and there are <NUM> SSBs. Network signals ra-PreambleStartIndex for SI request in SI-Request-Resources. PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + <NUM>' are used for this SI request. If the number of SSBs per PRACH occasion is less than <NUM>, preamble index = ra-PreambleStartIndex is used for SI request for any SSB.

If configuration type is dedicated, this means there is a dedicated configuration for each on Demand SI message. This can be indicated by signaling configuration type set to 'dedicated. ' Alternately, if dedicatedConfig is included then configuration type is dedicated. In this case, if the number of SSBs per PRACH occasion is larger than or equal to <NUM>.

If the number of SSBs per PRACH occasion is less than or equal to <NUM>, preamble index = ra-PreambleStartIndex + n-<NUM> are used for nth On-Demand SI message for any SSB.

UE selects a suitable SSB (above a threshold configured by network in system information). UE then selects a preamble corresponding to this SSB from the preambles corresponding to SI message which UE wants to request. UE also selects a RACH occasion corresponding to this SSB. UE then transmits Msg1 using selected preamble and RACH occasion.

In an embodiment, ra-PreambleStartIndex is equal to totalNumberOfRA-Preambles wherein totalNumberOfRA-Preambles is signaled in system information (e.g. SIB1). The totalNumberOfRA-Preambles indicates the number of RA preambles used for normal random access procedure other than SI request. UE can determine the list of ra-PreambleIndexes based on ra-PreambleStartIndex, number of SSBs per RACH Occasion and configuration type.

If configuration type is common, this means there is a common configuration for all on Demand SI messages. This can be indicated by signaling configuration type set to 'common'. Alternately, if dedicatedConfig is not included then configuration type is common. In this case Msg1 (i.e. SI request) transmitted by UE does not indicate request for a specific SI message and upon reception of Msg1 network transmits all On-Demand SI messages. In this case PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + number of SSBs per RACH Occasion -<NUM>' are used for SI request. The 'ith' preamble in this list corresponds to ith SSB amongst the SSBs associated with a RACH Occasion. In the example of <FIG>, <FIG> SSBs are mapped per PRACH occasion and there are <NUM> SSBs. Network signals ra-PreambleStartIndex for SI request in SI-Request-Resources. PRACH preambles from ra-PreambleStartIndex to 'ra-PreambleStartIndex + <NUM>' are used for this SI request.

If configuration type is dedicated, this means there a dedicated configuration for each on Demand SI message. This can be indicated by signaling configuration type set to 'dedicated'. Alternately, if dedicatedConfig is included then configuration type is dedicated. In this case, if the number of SSBs per PRACH occasion is larger than or equal to <NUM>,.

In the existing system UE determines the DRX cycle (T) for calculating its paging occasion (PO) as follows:.

In NR this may not work as T2 is multiple of remaining minimum system information (RMSI) PDCCH monitoring occasions interval. It is multiple of <NUM> or multiple of SS burst period (i.e. <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). Since T1 is configured by upper layer and is agnostic to RMSI PDCCH monitoring occasions intervals.

<FIG> illustrates determining the DRX cycle of UE where RMSI is frequency division multiplexed (FDMed) with SSB according to an embodiment of the disclosure.

<FIG> illustrates determining the DRX cycle of UE where RMSI is not FDMed with SSB according to an embodiment of the disclosure.

In an embodiment, UE determines the DRX cycle (T) for calculating its PO as follows:.

CA aspects are not considered yet for BWP switching upon initiation of RA procedure.

For RA procedure initiated on secondary cell (SCell) (e.g. SCell X), RAR is received on special cell (SpCell). The term SpCell refers to the primary cell (PCell) of the master cell group (MCG) or the primary secondary cell (PSCell) of the secondary cell group (SCG). A SCell provides additional radio resources on top of SpCell.

It is proposed that if RA procedure is initiated on SCell and if CSS is not configured in active DL BWP of SpCell, UE switch to initial DL BWP of SpCell. If RA resources are not configured in active UL BWP, switching to initial DL BWP is applied for RA procedure initiated on SpCell. If RA resources are configured in active UL BWP, switching to DL BWP linked to UL BWP is applied for RA procedure initiated on SpCell.

Upon initiation of the RA procedure on a Serving Cell, the MAC entity shall for this Serving Cell:.

In an embodiment, upon initiation of RA procedure on a serving cell, a UE identifies whether PRACH occasions are configured for an active UL BWP of a serving cell. If PRACH occasions are configured for the active UL BWP, and the Serving Cell is a SpCell, and the active DL BWP does not have the same bwp-Id, i.e., BWP identifier as the active UL BWP, the UE switches the active DL BWP to the DL BWP with the same bwp-Id, i.e., BWP identifier as the active UL BWP.

If PRACH occasions are not configured for the active UL BWP, the UE switches the active UL BWP to an initial UL BWP configuration for the serving cell. The initial UL BWP configuration may be indicated by initialUplinkBWP in system information. If PRACH occasions are not configured for the active UL BWP and the Serving Cell is a SpCell, the UE also switches the active DL BWP to an initial DL BWP configuration of the SpCell. The initial DL BWP configuration may be indicated by initialDownlinkBWP in system information.

The UE performs the RA procedure on the active DL BWP of the SpCell and the active UL BWP of the serving cell.

During the Random Access procedure on a Serving Cell, the MAC entity shall for this Serving Cell:.

Upon initiation of the contention-based Random Access procedure on a Serving Cell, the MAC entity shall for this Serving Cell:.

<FIG> is a block diagram of a terminal according to an embodiment of the disclosure.

Referring to <FIG>, a terminal includes a transceiver <NUM>, a controller <NUM> and a memory <NUM>. The controller <NUM> may refer to a circuitry, an ASIC, or at least one processor. The transceiver <NUM>, the controller <NUM>, and the memory <NUM> are configured to perform the operations of the UE illustrated in the drawings, e.g., <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, or described above. Although the transceiver <NUM>, the controller <NUM>, and the memory <NUM> are shown as separate entities, they may be realized as a single entity like a single chip. Alternatively, the transceiver <NUM>, the controller <NUM>, and the memory <NUM> may be electrically connected to or coupled with each other.

The transceiver <NUM> may transmit and receive signals to and from other network entities, e.g., a base station.

The controller <NUM> may control the UE to perform functions according to one of the embodiments described above.

For example, the controller <NUM> is configured to identify whether PRACH occasions are configured for the active UL BWP. If the PRACH occasions are not configured for the active UL BWP and the serving cell is a SpCell, the controller <NUM> is configured to switch the active DL BWP to an initial DL BWP configuration indicated by initialDonlinkBWP in system information. In addition, the controller <NUM> may be further configured to switch the active UL BWP to an initial UL BWP configuration for the serving cell indicated by initialUplinkBWP in system information if the PRACH occasions are not configured for the active UL BWP. In addition, the controller <NUM> may be further configured to switch the active DL BWP to a DL BWP with the same bwp-Id as the active UL BWP if the PRACH occasions are configured for the active UL BWP and the serving cell is the SpCell and the active DL BWP does not have a same bwp-Id as the active UL BWP. The controller <NUM> is configured to perform the RA procedure on the active DL BWP of the SpCell and the active UL BWP of the serving cell.

For example, the controller <NUM> is configured to determine whether a MAC SDU is associated with a CCCH or DCCH. If the MAC SDU corresponds to a CCCH SDU, the controller <NUM> is configured to identify the size of the MAC SDU to determine a LCID field of MAC subheader. The controller <NUM> is configured to generate a MAC PDU including the MAC subheader and the MAC SDU, and to control the transceiver <NUM> to transmit a Msg <NUM> associated with the generated MAC PDU to the gNB. The size of the MAC SDU may be either <NUM> or <NUM> bits. If the size of the MAC SDU is <NUM> bits, the controller is configured to set the LCID field to a first predetermined value. Otherwise, the controller is configured to set the LCID field to a second predetermined value different from the first predetermined value.

For example, the controller <NUM> is configured to control the transceiver <NUM> to receive information on resources for SI request (i.e., SI-Request-Resources) from the base station. The information on resources for SI request may include information on a start index of at least one RA preamble for SI request (i.e., ra-PreambleStartIndex). The controller <NUM> is configured to control the transceiver to receive the information on resources for the SI request in SIB1. The controller <NUM> may be configured to control the transceiver <NUM> to receive information on a number of SSBs per a PRACH occasion in the SIB1. The controller <NUM> is configured to receive at least one SSB from the base station, and select an SSB among the at least one SSB. The controller <NUM> may be configured to select an SSB above a threshold among the at least one SSB. The controller <NUM> may be configured to select any SSB if none of the at least one SSB is above the threshold. The controller <NUM> may be configured to determine a list of preambles for the SI request based on the information on the start index and the information on the number of SSBs per the PRACH occasion. The controller <NUM> is configured to determine a preamble for the SI request corresponding to the selected SSB based on the information on the start index. The controller <NUM> is configured to control the transceiver <NUM> to transmit the determined preamble based on a PRACH occasion corresponding to the selected SSB.

In an embodiment, the operations of the terminal may be implemented using the memory <NUM> storing corresponding program codes. Specifically, the terminal may be equipped with the memory <NUM> to store program codes implementing desired operations. To perform the desired operations, the controller <NUM> may read and execute the program codes stored in the memory <NUM> by using a processor or a central processing unit (CPU).

<FIG> is a block diagram of a base station according to an embodiment of the disclosure.

Referring to <FIG>, a base station (BS) includes a transceiver <NUM>, a controller <NUM> and a memory <NUM>. The controller <NUM> may refer to a circuitry, an ASIC, or at least one processor. The transceiver <NUM>, the controller <NUM> and the memory <NUM> are configured to perform the operations of the network (e.g., gNB) illustrated in the drawings, e.g., <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, or described above. Although the transceiver <NUM>, the controller <NUM>, and the memory <NUM> are shown as separate entities, they may be realized as a single entity like a single chip. Alternatively, the transceiver <NUM>, the controller <NUM>, and the memory <NUM> may be electrically connected to or coupled with each other.

The transceiver <NUM> may transmit and receive signals to and from other network entities, e.g., a terminal.

The controller <NUM> may control the BS to perform functions according to one of the embodiments described above.

For example, the controller <NUM> is configured to control the transceiver <NUM> to receive a Msg3 associated with a MAC PDU from a terminal. If the received MAC SDU is a CCCH SDU, the controller is configured to identify the size of the MAC SDU based on a LCID field of the MAC subheader.

Claim 1:
A method performed by a terminal in a wireless communication system, the method comprising:
receiving, from a base station, a system information block <NUM>, SIB1, including information on a list of system information, SI, request resources, and information on a number N of synchronization signal blocks, SSBs per one random access channel, RACH, occasion, wherein an entry included in the list corresponds to an SI message and includes a random access, RA, preamble start index for an SI request;
in case that a random access procedure is initiated to request the SI message, identifying an SSB;
identifying a random access preamble among at least one random access preamble for the SI message, wherein the random access preamble corresponds to the SSB;
identifying a physical random access channel, PRACH, occasion corresponding to the SSB; and
transmitting, to the base station, the random access preamble in the PRACH occasion for the SI message,
wherein, in case that the N is larger than or equal to <NUM>, an index of i-th random access preamble among the at least one random access preamble corresponds to i-th SSB among the N of the SSBs and is determined as the RA preamble start index plus the i, and
wherein the i is indexed from <NUM> to N - <NUM>.