Efficient transmission of system information

Abstract

Various methods of transmitting minimum system information from a base station in an orthogonal frequency division multiplexing (OFDM) transmission system are presented. The master information block (MIB) is multiplexed with the remaining minimum system information (RMSI) information in the form of a synchronization signal / physical broadcast channel (SS / PBCH) block, which includes a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH), and the RMSI information is transmitted within the frequency span of control resource set #0 (CORESET #0). The SS / PBCH and RMSI information occupy the same time occupancy, but can include different numbers of OFDM symbols. The OFDM system can operate in licensed and unlicensed spectrum.

Description

TECHNICAL FIELD

[0001] The disclosure below relates to transmission of system information in a wireless communication system, and more specifically to transmission of minimum system information in high frequency operation. BACKGROUND

[0002] Wireless communication systems such as the third-generation (3G) mobile telephone standards and technologies are well known, with the 3rd Generation Partnership Project (3GPP) having developed such 3G standards and technologies, and generally third generation wireless communication has been developed to support macro cell mobile telephone communication, with communication systems and networks moving towards broadband and mobile systems.

[0003] In a cellular wireless communication system, User Equipment (UE) is connected to a Radio Access Network (RAN) via a wireless link. The RAN comprises a set of base stations which provide the wireless link to UEs located in cells covered by the base stations, and includes an interface to a Core Network (CN) which has functionality to control the overall network. It will be appreciated that the RAN and CN each perform respective functions in relation to the overall network. For convenience, the term "cellular network" will be used to represent the combination of the RAN and CN, and it will be understood that the term is also used to represent each of the systems for performing the disclosed functionality.

[0004] The 3rd Generation Partnership Project has developed so-called Long Term Evolution (LTE) systems, namely the Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) for mobile access networks of one or more macro cells supported by base stations known as eNodeBs or eNBs. More recently, LTE has further evolved towards so-called 5G or new radio (NR) systems, with one or more cells of the system being supported by base stations known as gNBs. NR was introduced with an Orthogonal Frequency Division Multiplexed (OFDM) physical transmission format.

[0005] The NR protocol wants to provide an option to operate in unlicensed radio frequency bands, referred to as NR-U. When operating in unlicensed radio frequency bands, the gNB and the UE have to contend for access to the physical medium / resources with other devices. For example, Wi-Fi, NR-U and LAA can use the same physical resources.

[0006] A trend in wireless communication is to provide services with lower latency and higher reliability. For example, NR aims to support Ultra-reliable and low-latency communications (URLLC), and massive Machine-Type Communications (mMTC) aims to provide low latency and high reliability for small data packets (typically 32 bytes). Currently, a user plane latency of 1 ms has been proposed with a reliability of 99.99999%, and in terms of the physical layer, a scheme that satisfies a packet loss rate of 10 -5 or 10 -6 has been proposed.

[0007] The mMTC service aims to support a large number of devices with a high energy-efficient communication channel for a long life period. In this case, data transmission between each device is sporadic and infrequent. For example, a cell can have to support tens of thousands of devices.

[0008] In NR, a UE needs to decode minimum system information (MSI) broadcast by a base station to initiate any form of communication. The MSI is broadcast in the form of a master information block (MIB) on a physical broadcast channel (PBCH), which carries basic system information, and remaining system information (RMSI) as a system information block type 1 (SIB1). A control resource set (CORESET) configured through the MIB is referred to as CORESET #0, which is used to transmit downlink control information (DCI) indicating resources scheduled for a physical downlink shared channel (PDSCH) carrying the SIB1.

[0009] To initiate communication, the UE decodes the MIB as part of a cell search procedure, which enables the UE to obtain time and frequency synchronization with the base station and detect a physical layer cell identifier (ID). The UE receives a synchronization signal (SS) in the form of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), which are consecutive signals that together define a physical broadcast channel (PBCH) and form a SS / PBCH block. By decoding the PBCH, the UE is able to decode the MIB to complete configuration and receive and initiate downlink (DL) and uplink (UL) communication, respectively.

[0010] The following disclosure relates to various improvements to cellular wireless communication systems. SUMMARY

[0011] The invention is defined by the claims, wherein a method of transmitting minimum system information from a base station in an orthogonal frequency division multiplexing (OFDM) transmission system is provided, characterized in that the method comprises the steps of transmitting a master information block (MIB) in the form of a synchronization signal / physical broadcast channel (SS / PBCH) block and transmitting remaining minimum system information (RMSI) information on at least one other channel, wherein the step of transmitting comprises multiplexing the SS / PBCH with the RMSI information and transmitting the RMSI information within a frequency span of a control resource set #0 (CORESET #0).

[0012] The RMSI information comprises at least a system information block 1 (SIB1) RMSI PDCCH and / or PDSCH channel.

[0013] The SS / PBCH block is transmitted on n at least one OFDM symbol and the RMSI information is transmitted on m at least one OFDM symbol, wherein n is a multiple of m.

[0014] The SS / PBCH block is transmitted on n at least one OFDM symbol and the RMSI information is transmitted on m at least one OFDM symbol, wherein n is equal to m.

[0015] The step of multiplexing comprises multiplexing in time.

[0016] The OFDM system operates in licensed and unlicensed spectrum.

[0017] A subcarrier spacing (SCS) of a channel carrying the SS / PBCH block is a multiple of a SCS of a channel carrying the RMSI information, such that the SS / PBCH block and the RMSI information occupy the same time period.

[0018] the start of the SS / PBCH block and the start of the RMSI information are aligned.

[0019] the SS / PBCH block and the RMSI information are equal in time and terminate at the same time.

[0020] a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) are transmitted in series or in parallel.

[0021] A base station configured to perform the methods described herein is also provided.

[0022] A UE configured to decode an MIB transmitted according to the methods described herein is also provided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Further details, aspects and embodiments of the application are described by way of example only, and with reference to the drawings of which:-

[0024] Figure 1 Selected elements in a cellular wireless communication network are illustrated. DETAILED DESCRIPTION

[0025] Those skilled in the art will realize that the specific details, aspects and embodiments described herein are merely illustrative and that the teachings set forth herein are applicable to a wide variety of alternative configurations.

[0026] Figure 1 A schematic diagram showing three base stations (e.g. eNBs or gNBs, depending on the particular cellular network standard and terminology) forming a cellular network is shown. Typically, each base station will be deployed by a cellular network operator to provide geographical coverage for UEs in that area. The base stations form a Radio Area Network (RAN). Each base station provides wireless signal coverage for UEs in its area or cell. The base stations are interconnected by an X2 interface and connected to a core network by an S1 interface. As will be appreciated, only some basic details are shown here to facilitate an explanatory illustration of key features of a cellular network. A PC5 interface is provided between UEs to enable SideLink (SL) communication. As will be appreciated, the interface and component names shown are merely examples and different naming conventions can be used for different systems operating according to the same principles. Figure 1

[0027] ​Each base station includes hardware and software for implementing RAN functionality, including functionality for communicating with the core network and other base stations, carrying control and data signals between the core network and UEs, and maintaining or otherwise facilitating wireless communication with UEs associated with each base station. The core network includes hardware and software for implementing network functionality, such as management and control of the overall network, and routing of calls and data.

[0028] The standard (Section 7.4.3.1 of 3GPP Technical Standard 38.211) defines the time-frequency structure of the SS / PBCH block. In the time domain, one SS / PBCH block consists of 4 OFDM symbols, which are numbered in increasing order from 0 to 3 within the SS / PBCH block.

[0029] In the frequency domain, one SS / PBCH block consists of 240 consecutive subcarriers (20 resource blocks, each of which includes 12 subcarriers), which are numbered in increasing order from 0 to 239 within the SS / PBCH block.

[0030] The MIB carries the system frame number (SFN), the common subcarrier spacing (SCS) (the common SCS is the SCS used for decoding SIB1), the demodulation reference symbol (DMRS), and information necessary for the UE to decode SIB1. It also provides information on whether the current cell is barred.

[0031] The base station transmits the physical downlink control channel (PDCCH) on a preconfigured region of the time-frequency grid, referred to as a control resource set (CORESET). The search space provides a configuration associated with a given CORESET and specifies the symbols and physical resource blocks (PRBs) that the UE uses to attempt PDCCH decoding. 5G NR defines common and UE-specific search spaces.

[0032] The Type 0 common search space is used for PDCCH transmissions that allocate resources for SIB1. This search space is indicated using the MIB, which is carried on the PBCH, and can also be indicated using the PDCCH-ConfigCommon structure. The Type 0 common search space maps to the CORESET identified as 0 (CORESET #0). The PDCCH used for SIB1 resource allocation is transmitted using cyclic redundancy check (CRC) encoded with the system information (SI) radio network temporary identifier (RNTI), which is a fixed parameter known to all devices. This PDCCH is transmitted using DCI format 1_0.

[0033] More precisely, the PBCH embedded in the SS / PBCH block carries the following information elements (3GPP Technical Standard 38.331 and 3GPP Technical Standard 38.213):

[0034] • subCarrierSpacingCommon

[0035] • PDCCH-ConfigSIB1-controlResourceSetZero

[0036] • PDCCH-ConfigSIB1-searchSpaceZero

[0037] subCarrierSpacingCommon provides the SCS used for transmission of the PDCCH carrying the SIB1 allocation, which can be different from the SCS used for transmission of the SS / PBCH block. The controlResourceSetZero information element provides an index of a row in a CORESET configuration table using a 4-bit indication. There is a different CORESET configuration table for each combination of (SCS SS / PBCH, SCS PDCCH). Once the UE has decoded the SS / PBCH block and found subCarrierSpacingCommon, it can use the index to point to the relevant CORESET configuration table to find the SCS combination used for the SS / PBCH block and for the PDCCH of the SIB1. For each constituent row, the CORESET configuration table provides the number of PRBs, the number of symbols, the resource block offset relative to the SS / PBCH block, and the multiplexing pattern of the SS / PBCH block and the CORESET. 3GPP Technical Standard 38.213 contains more detailed information.

[0038] searchSpaceZero provides an index (4-bit indication) pointing to a specific row in a search space configuration table. There are multiple search space configuration tables defined in 5G NR, each table being applicable for a given frequency range and a given multiplexing pattern of the SS / PBCH block and the CORESET. The search space configuration table provides the location of the search space in terms of frames, slots, and the number of search space sets per slot so that the UE can determine the correct search space for PDCCH decoding attempts. 3GPP Technical Standard 38.213 contains more detailed information.

[0039] The PDCCH scheduling SIB1 uses DCI format 1 0 which provides resource allocation and other parameters needed for decoding the PDSCH carrying SIB1. DCI format 1 0 carries one field, the time domain resource assignment (TDRA). The TDRA indication from the PDCCH and the dmrs-TypeA-Position indication from the MIB help to select the appropriate row from the TDRA table. Each row in this table provides information on the time resources using a slot offset, a starting symbol and the length of the scheduled resources for the PDSCH that will carry the SIB1 information.

[0040] SIB1 provides base station selection information, system information scheduling information, serving base station configuration and other emergency services related information elements. The serving base station configuration includes downlink configuration common information, uplink configuration common information. The DL configuration common information provides information on the DL frequency, DL bandwidth part (BWP) and configuration of paging and broadcast control channels in turn. The BWP configuration includes common configuration of PDCCH and PDSCH. The UL configuration common information provides UL frequency information, initial UL BWP. The BWP UL provides information on RACH, PUCCH and PUSCH configuration.

[0041] For example, standards such as 3GPP specify two frequency ranges, frequency range FR1 and FR2. FR1 was originally up to 6 GHz, but was later extended to 7.125 GHz. FR2 was originally specified from 24.25 GHz to 52.6 GHz. The 15th and 16th editions of 5G New Radio (NR) were developed for operation in these frequency ranges. The 17th edition focuses on extending FR2 operation up to 71 GHz. These extensions can go up to 100 GHz or even higher, as the wide availability of spectrum at such high carrier frequencies and antenna / RF advances can allow efficient communication at these frequencies, which was previously considered very difficult. Systems operating at such high carrier frequencies need to resort to beam-based transmission. These systems need to transmit SS / PBCH blocks in a broadcast manner in each beam direction with a given periodicity, as well as the remaining minimum system information SIB1 or RMSI (scheduling command in PDCCH and information in PDSCH). For FR2, a base station can use up to 64 beams. This results in a considerable overhead and imposes certain scheduling limitations due to the mandatory use of beam sweeping.

[0042] For beam-based operation, the base station transmits the SS / PBCH block, the PDCCH in CORESET 0, and the related PDSCH carrying SIB1 in each beam direction. Due to the large number of active beams, the user density can be unevenly distributed, and thus the transmission of the SS / PBCH block and the PDCCH and PDSCH of SIB1 needs to activate each beam in the shortest duration that allows such transmissions, resulting in a waste of time-frequency resources, leading to very low system efficiency. This problem will become more severe for the new combinations of SCS for the SS / PBCH block and the PDCCH scheduling SIB1. This problem is more severe in the case of unlicensed spectrum due to channel uncertainty (loss of channel ownership in the gap of these transmissions or due to the need to perform a channel access procedure between these transmissions).

[0043] The transmission of minimum system information describes the method of multiplexing between the SS / PBCH block and CORESET 0. In addition, to optimize the transmission of the SS / PBCH block and SIB1 and the resource allocation to the PDSCH, the system overhead needed to transmit such control information can be reduced when combined with the described multiplexing pattern. The gap minimization schemes described here provide protection against loss of channel ownership. This makes these schemes more attractive for operation in shared carriers. In addition, the described schemes circumvent the requirement to ensure channel access after the transmission gap. Therefore, the methods described herein are suitable for unlicensed spectrum.

[0044] The CORESET configuration and PDSCH resource scheduling options ensure that the transmission of the PDCCH in CORESET 0 and the scheduled PDSCH are confined within the same time period as the SS / PBCH block. This achieves the minimum activation time requirement in each single beam and minimizes the beam switching that would result in delay and transition. This uses a relatively large frequency resource span, as the different pieces of minimum system information are multiplexed in frequency. This can be perfectly acceptable at higher carrier frequencies where large bandwidths are typically available. This is suitable for operation in unlicensed shared carriers, as it reduces the requirement to perform channel sensing in different beams and also reduces the likelihood of loss of channel ownership to some other device during the SS / PBCH block and RMSI transmission. The individual pieces of system information are transmitted in one indivisible cluster.

[0045] The system transmits the minimum system information of the master information block (MIB) and the remaining minimum system information (RMSI), also known as SIB1, in the SS / PBCH block in the shortest possible time occupancy. The SS / PBCH block uses a fixed structure consisting of 4 OFDM symbols and transmits the RMSI (scheduling PDCCH and PDSCH) in a way that is completely overlapping in time with the SS / PBCH block, although they employ different subcarrier spacings (SCS). This approach uses a combination of SCS where the SCS of the SS / PBCH block can be equal to the SCS of the PDCCH scheduling the RMSI or 2 or 4 times the SCS of the PDCCH scheduling the RMSI. For these SCS combinations, precise CORESET0, search space type 0 layout (carrying the PDCCH scheduling the RMSI) and default data allocation items of the PDSCH are configured. These proposed configurations enable the multiplexing of the SS / PBCH block with the RMSI (PDCCH plus PDSCH) in frequency, thus using the minimum time occupancy for the transmission of the minimum system information without any restrictions on the SCS used. This results in a significant reduction in the overhead of the system information transmission. The three transmission units (SS / PBCH block, PDCCH and PDSCH of the RMSI) are always transmitted in a single cluster, minimizing the impact of channel uncertainty.

[0046] The RMSI is multiplexed into the same time occupancy as the SS / PBCH block to avoid the RMSI extending outside the SS / PBCH block. This in turn reduces the overhead per beam direction and creates a decoding advantage due to the increased amount of RMSI data transmitted in the PDSCH.

[0047] Each base station transmits one SS / PBCH block, allowing each UE to synchronize, and then transmits SIB1 (RMSI) scheduled through search space set 0 on CORESET#0. This provides the UE with the minimum system information needed to decode downlink (DL) data or initial uplink (UL) data transmissions. This forces the base station to transmit the SS / PBCH block, the PDCCH transmitted on the CORESET#0 scheduling the SIB1, and the SIB1 in all beam directions as part of the basic cell coverage, enabling the UE to contact the base station based on this minimum system information.

[0048] In order to minimize the overhead of the MIB / SIB1 transmission and avoid channel uncertainty on shared carriers, the SS / PBCH block, the PDCCH and the SIB1 (RMSI) need to be multiplexed in the least number of symbols. The SS / PBCH block is a set of fixed signaling that is transmitted on 4 OFDM symbols (OS) at the subcarrier spacing (SCS) of the SS / PBCH block.

[0049] Since SS / PBCH block and SIB1 (RMSI) use different subcarrier spacing (SCS), a given multiplexing pattern can not necessarily apply to all combinations of SCS for SS / PBCH block and PDCCH scheduling RMSI.

[0050] This method enables transmission and multiplexing of SIB1 when the SCS used by SS / PBCH block is 4 times larger than the SCS of PDCCH scheduling PDSCH carrying SIB1. The 4 symbols carrying SS / PBCH block is equivalent to using only one symbol in the numerology set for PDCCH of SIB1. This setup applies to {SS / PBCH block, PDCCH} SCS including {240, 60}, {480, 120}, {960, 240}, {1920, 480} KHz and other potential SCS combinations with similar ratios. The proposal for multiplexing of CORESET 0 with SS / PBCH block and related PDSCH carrying SIB1 (RMSI) is shown below. SS / PBCH block is transmitted on 4 OFDM symbols n, n+1, n+2 and n+3. This is equivalent to one OFDM symbol "m" in the numerology set used by PDCCH in CORESET 0 and SIB1 PDSCH.

[0051]

[0052] Table 1

[0053] CORESET 0 is configured on one OFDM symbol which spans the same time period as the 4 OFDM symbols of SS / PBCH block. Furthermore, the PDCCH transmitted in CORESET 0 schedules PDSCH carrying SIB1 (RMSI) in a time period of 1 OFDM symbol which is also aligned with CORESET 0 and SS / PBCH block.

[0054] The CORESET 0 configuration, search space type 0 configuration, and the default PDSCH allocation table, i.e., the so-called time domain resource assignment (TDRA) table, need to be updated so that the CORESET 0 configuration can support a single-symbol configuration with a sufficient number of PRBs. To this end, it can be allowed that the CORESET #0 configuration occupies 192 or more PRBs. The related search space configuration table should be increased with a few entries so that the index value of the first symbol is aligned with the first OFDM symbol of the SS / PBCH block. The default TDRA table for PDSCH resource allocation supports the scheduling of PDSCH so that the starting OFDM symbol (denoted as S in the TDRA table) is aligned with the starting position of CORESET 0, and the length of the allocated resource (denoted as L in the TDRA table) can be configured to be 1 OFDM symbol. Since the PDSCH is transmitted in the same slot as the PDCCH in CORESET 0, the slot offset for this entry should be set to zero.

[0055] The default active DL bandwidth part (BWP) is confined within the frequency span of CORESET 0. This means that the UE should not be scheduled outside the frequency resource span indicated for CORESET 0. The base station can then update the active DL BWP through SIB1 signaling and require the base station to update the active DL BWP to be larger than the frequency span of CORESET 0. To overcome this limitation, the system is configured with a CORESET 0 on one frequency span and uses a portion of the configured CORESET 0 PRBs to transmit the PDCCH. This allows the scheduling of PDSCH carrying RMSI on another portion of the frequency resource span indicated for CORESET 0 by transmitting the RMSI data on the PDSCH scheduled in the resources configured for CORESET 0. By way of example only, Table 1 uses a PDCCH transmitted in CORESET 0 that utilizes 50% of the resource frequency span of the available CORESET 0, with the remaining 50% of the resource frequency span of the available CORESET 0 used for the RMSI PDSCH. One allowed solution is that the entire frequency span of CORESET 0 can be indicated in the PDCCH as the resource for PDSCH, and the UE rate-matches it using the decoded PDCCH. Another solution is to use the frequency allocation field in the PDCCH to precisely allocate the frequency location of the PDSCH within CORESET 0.

[0056] The above examples show the SS / PBCH block, CORESET 0 and RMSI PDSCH without any frequency gap. But this is just an example, and it should be understood that the actual configuration / scheduling can include frequency gaps (PRBs) between the blocks. Although the SCS is different, these blocks span the same time period, enabling the minimization of the duration for transmission of SS / PBCH block and RMSI. Similarly, the actual frequency resource span of CORESET 0, RMSI PDSCH can be larger or smaller than the SS / PBCH block, or split around the SS / PBCH block. This can be easily configured by the resource block offset indication as part of the CORESET 0 configuration.

[0057] Furthermore, as another alternative, Table 2 below shows an example where the SCS used for SS / PBCH block RMSI transmission is twice the SCS used for PDCCH scheduling the PDSCH carrying SIB1 (RMSI). The 4 OFDM symbols carrying the SS / PBCH block is equivalent to two OFDM symbols in the numerology of the PDCCH of SIB1. This setup applies to {SS / PBCH block, PDCCH} SCS combinations including {120, 60}, {240, 120}, {480, 240}, {960, 480}, {1920, 960} KHz and other potential SCS combinations with this ratio.

[0058] The two OFDM symbols in the PDCCH numerology (in CORESET 0) are used for both CORESET 0 configuration and scheduling of RMSI PDSCH in a frequency multiplexed manner with the SS / PBCH block. This multiplexing is shown in Table 2. The table shows the SS / PBCH block spanning 4 OFDM symbols n, n+1, n+2 and n+3. The two equivalent OFDM symbols m and m+1 in the PDCCH numerology are used to configure CORESET 0 and allocate resources for RMSI PDSCH, which is scheduled by the PDCCH transmitted in CORESET 0.

[0059]

[0060] Table 2

[0061] This can be achieved by a CORESET 0 configuration supporting 2 OFDM symbols, a search space type 0 configuration allowing it to be aligned with the first symbol of the SS / PBCH block, and a PDSCH time domain resource allocation of 2 OFDM symbols having the same starting symbol as the CORESET 0, which is aligned with the first OFDM symbol of the SS / PBCH block.

[0062] For operation of the initial active DL BWP restricted to the frequency resource span of the CORESET 0 configuration, the RMSI PDSCH must be restricted in this resource. Once the base station updates the active DL BWP, the RMSI PDSCH can be allocated within this DL BWP, which does not have to be restricted within the frequency resource span of the CORESET 0 configuration. If the initial active DL BWP is restricted to the frequency resource span of the CORESET 0 configuration, the PDCCH scheduling the RMSI PDSCH can be transmitted on a portion of the CORESET 0 configured resources, while the remaining portion of the active DL BWP can be used to schedule the RMSI PDSCH, as shown in Table 2.

[0063] In this example, the scheduling command (PDCCH) and data carrying the MSI (PDSCH) are frequency multiplexed with the SS / PBCH block, while being time multiplexed with each other. The 4 OFDM symbols of the SS / PBCH block correspond to two OFDM symbols in the PDCCH numerology. The two OFDM symbols in the PDCCH numerology (in CORESET 0) are equally divided in time, with 1 OFDM symbol allocated for the CORESET 0 configuration and the second OFDM symbol scheduled for the RMSI PDSCH. Thus, this method has the CORESET 0 configuration and the RMSI PDSCH scheduling in TDMA fashion with each other. The CORESET 0 and SIB1 (RMSI) PDSCH are collectively frequency multiplexed with the SS / PBCH block.

[0064]

[0065] Table 3

[0066] Table 3 shows CORESET 0 configuration and RMSI PDSCH scheduling. The SS / PBCH block indicates a CORESET 0 configuration of 1 OFDM symbol, and the PDCCH transmitted within the CORESET 0 schedules a PDSCH (carrying RMSI) with a starting symbol aligned to the last 2 OFDM symbols of the SS / PBCH block and a length of 1 OFDM symbol. The SCS of {SS / PBCH block, PDCCH} is x, x / 2} kHz, the CORESET configuration supports a CORESET 0 configuration of 1 OFDM symbol, and search space type 0 needs to define a configuration with one entry that is aligned to the first OFDM symbol of the SS / PBCH block, and the default TDRA table has one entry with a PDSCH length of 1 OFDM symbol starting from symbol m+1, which is aligned to the last 2 OFDM symbols of the SS / PBCH block. Thus, the CORESET 0 and PDSCH are time multiplexed, and the frequency resource span for PDSCH scheduling can be limited within the frequency resource span of the CORESET 0 configuration and located within the initial active DL BWP.

[0067] CORESET 0 can be configured on a single OFDM symbol aligned to the first two OFDM symbols of the SS / PBCH block, where the SIB1 (RMSI) PDSCH is allocated to time resources spanning two OFDM symbols aligned to the 4 OFDM symbols of the SS / PBCH block, as shown in Table 4. Thus, the CORESET 0 and PDSCH can be frequency multiplexed in the first OFDM symbol. This can be used in cases where a single symbol PDSCH is considered insufficient to carry SIB1 data. In this case, additional resources can be allocated for the PDSCH to provide better protection. In this example, the PDCCH and PDSCH for RMSI are frequency multiplexed with the SS / PBCH block but are time and frequency multiplexed with each other.

[0068] For operation of the initial active DL BWP limited within the frequency resource span of the CORESET 0 configuration, the RMSI PDSCH must be limited in this same resource. The PDCCH is transmitted on a portion of the frequency span resource of the CORESET 0 configuration, and the remaining portion of the frequency resource span of the CORESET 0 configuration can be used to transmit the SIB1 PDSCH.

[0069]

[0070] Table 4

[0071] Table 5 shows SS / PBCH block and PDCCH on CORESET 0, which schedules PDSCH carrying RMSI with the same SCS. The four OFDM symbols in the PDCCH numerology set (in CORESET 0) are split such that 1 OFDM symbol is used for CORESET 0 configuration and 3 OFDM symbols are allocated to RMSI PDSCH. SIB1 can contain proportionally more information than carried in the PDCCH transmitted in CORESET 0, which proportionally provides more RMSI PDSCH resources. To employ this multiplexing pattern, the default time domain resource allocation in the TDRA table needs to be augmented with new entries to allow scheduling PDSCH on the length of 3 OFDM symbols, which starts at the 2nd OFDM symbol n+1 of the SS / PBCH block.

[0072]

[0073] Table 5

[0074] In the case of time multiplexing of CORESET 0 and PDSCH, the frequency resource span scheduled for PDSCH can be limited within the frequency resource span of CORESET 0 configuration and located within the initial active DL BWP. This can be used in the case that the active DL BWP is limited within the frequency resource range of CORESET 0.

[0075] Table 6 illustrates a method where the four OFDM symbols in the PDCCH numerology set (in CORESET 0) are split such that 1 OFDM symbol is used for CORESET 0 configuration and all 4 OFDM symbols aligned with the SS / PBCH block are allocated to RMSI PDSCH. This provides more resource allocation for SIB1 (RMSI) PDSCH compared to the example above and can enable faster transmission of minimum system information. Table 5 shows the proposed design including CORESET 0 configuration of 1 OFDM symbol and scheduling of 4 OFDM symbols for RMSI PDSCH.

[0076]

[0077] Table 6

[0078] For the case of active DL BWP limited to CORESET 0 configuration, PDCCH is transmitted on a portion of the CORESET 0 frequency resource span in the first OFDM symbol, the remaining frequency resource span on the first symbol and the next 3 symbols are used for transmission of SIB1 (RMSI) PDSCH.

[0079] Although not shown in detail, any device or apparatus forming part of the network can comprise at least a processor unit, a storage unit and a communication interface, wherein the processor unit, the storage unit and the communication interface are configured to perform the method of any aspect of the application. Further options and choices are described below.

[0080] The signal processing functionality of embodiments of the application can be implemented using computing systems or architectures known to those of skill in the relevant art in view of the teachings provided herein. The computing system can include a server, a client or both server and client. The server and client can be remote from each other and communicate via a network, for example, the Internet. The computing system can be a dedicated server, a server farm, a distributed system, a peer-to-peer system, or any combination thereof. The computing system can also include a desktop computer, a laptop computer, a handheld computer, a notebook computer, a tablet computer, a server computer, a handheld device, a personal digital assistant (PDA), a cellular telephone, a smartphone, a network router, a network switch, a network bridge, or any combination thereof. The computing system can include a plurality of computing devices, servers, or clients.

[0081] The computing system can also include a main memory, such as random access memory (RAM) or other dynamic storage devices, for storing information and instructions to be executed by the processor. Such main memory also can be for storing temporary variables or other intermediate information during execution of instructions by the processor. The computing system can likewise include a read only memory (ROM) or other static storage device for storing static instructions converted to signals an electrically or otherwise processed by the processing unit. The static storage can also be used for storing data or other computer files.

[0082] The computing system can also include an information storage system, which can include, for example, a media drive and a removable storage interface. The media drive can include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a compact disk (CD) or digital video drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. Storage media can include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by the media drive. The storage media can include a computer-readable storage medium for storing particular computer software or data.

[0083] In alternative embodiments, the information storage system can include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components can include, for example, a removable storage unit and an interface, such as a program cartridge and cartridge interface, a removable memory (for example, a flash memory or other removable memory module) and memory slot, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

[0084] The computing system can also include a communications interface. Such a communications interface can be used to allow software and data to be transferred between the computing system and external devices. Examples of communications interfaces can include a modem, a network interface (such as an Ethernet or other NIC card), a communications port (such as, for example, a universal serial bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via the communications interface are in the form of signals which can be electronic, electromagnetic, and optical or other signals capable of being received by a communications interface.

[0085] In this document, the terms "computer program product," "computer-readable medium," and the like can be used generally to refer to media such as, for example, memory, storage device, or storage unit. These and other forms of computer-readable media can store one or more instructions for use by a processor comprising a computer system to cause the processor to perform a specified operation. Such instructions, generally referred to as "computer program code" (which can be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform the functions of embodiments of the present application. Note that the code can directly cause a processor to perform specified operations, be compiled to do so, and / or be combined with other software, hardware, and / or firmware elements (e.g., libraries for performing standard functions) to do so.

[0086] The non-transitory computer-readable medium can include at least one of the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, and a flash memory. In embodiments where elements are implemented using software, the software can be stored in a computer-readable medium and loaded into the computing system using, for example, removable storage drive. The control module (in this example, software instructions or executable computer program code) when executed by a processor in the computer system causes the processor to perform the functions of the present application as described herein.

[0087] Furthermore, the inventive concept can be applied to any circuitry for performing signal processing functions within a network element. It is further envisioned that, for example, semiconductor manufacturers can utilize the inventive concept when designing stand-alone devices such as microcontrollers, such as application specific integrated circuits (ASICs) or digital signal processors (DSPs), and / or any other sub-system elements.

[0088] It will be appreciated that, for clarity, the above description has described embodiments of the application with reference to a single processing logic. However, the inventive concept can equally be implemented by means of a plurality of distinct functional units and / or processors to provide the functionality of the signal processing. Hence, the references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical, physical or time organization of such functions.

[0089] Aspects of the application can be implemented in any suitable form including hardware, software, firmware or any combination of these. The application can optionally be implemented at least partly as computer software running on one or more data processors and / or digital signal processors, and / or as appropriately programmed components of a FPGA device.

[0090] The elements and components of an embodiment of the application can therefore be physically, functionally and logically implemented in any suitable way. Indeed, the functionality can be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the application should not be limited to the specific embodiments set out herein, but should be given the broadest possible interpretation consistent with the description as set out above. Furthermore, the described features, techniques, compositions etc. can, in any appropriate combination, be used in the application. In the claims, the term comprising does not exclude the presence of other elements or steps than those listed in a claim. Furthermore, although individually listed, a plurality of means, elements or method steps can be implemented by use of one and the same item (e.g. a single processor or processor system can fulfil the functions of two or more listed means). The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. The application is not restricted to the details of the foregoing

[0091] embodiments, which can be varied in a number of ways. This applies also to the foregoing description as well as the accompanying drawings. In the claims, the term comprising does not exclude the presence of other elements or steps than those listed in a claim. Furthermore, although individually listed, a plurality of means, elements or method steps can be implemented by use of one and the same item (e.g. a single processor or processor system can fulfil the functions of two or more listed means). The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. The scope of the application is defined by the appended claims.

[0092] Furthermore, the order of features in the claims does not imply any specific order of performing the features and particularly, the order of individual steps in an method claim does not imply that the steps must be performed in that order. Rather, the steps can be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus references to "a", "an", "the", or "first" or "second" item in the claims are not to be construed as excluding a plurality or first and second items respectively. The terms "comprising", "comprise" and "when comprising" when used in this document specify the presence of stated features but do not preclude the presence or addition of one or more other features.

[0093] Although the application has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present application is limited only by the claims. Furthermore, although certain features of the application have been described with respect to particular embodiments thereof, it is to be understood that features of the application described herein can be combined with features of the other described embodiments where such combination is technically feasible and where the features are not mutually inconsistent. In the claims, the term "comprising" does not exclude the presence of other elements or steps than those listed in a claim.

Claims

1. A method of transmitting minimum system information from a base station in an orthogonal frequency division multiplexing (OFDM) transmission system, characterized by, The method comprises the steps of transmitting a master information block (MIB) in the form of a synchronization signal / physical broadcast channel (SS / PBCH) block and transmitting remaining minimum system information (RMSI) information on at least one other channel, wherein the transmitting step comprises multiplexing the SS / PBCH with the RMSI information such that the SS / PBCH and the RMSI information occupy the same time period and transmitting the RMSI information within a frequency span of a control resource set #0 (CORESET #0).

2. The method of claim 1, wherein, The RMSI information comprises at least a system information block 1 (SIB1) RMSI PDCCH and / or PDSCH channel.

3. The method of claim 1, wherein, The SS / PBCH block is transmitted over n number of OFDM symbols and the RMSI information is transmitted over m number of OFDM symbols, wherein n is a multiple of m.

4. The method of claim 1, wherein, The SS / PBCH block is transmitted over n number of OFDM symbols and the RMSI information is transmitted over m number of OFDM symbols, wherein n is equal to m.

5. The method of any one of claims 1 to 4, wherein, The multiplexing step comprises multiplexing in time.

6. The method of claim 5, wherein, The OFDM system operates in licensed and unlicensed spectrum.

7. The method of claim 1, wherein, A subcarrier spacing (SCS) of a channel carrying the SS / PBCH block is a multiple of a SCS of a channel carrying the RMSI information such that the SS / PBCH block and the RMSI information occupy the same time period.

8. The method of any one of claims 1 to 4, wherein, A start of the SS / PBCH block and a start of the RMSI information are aligned.

9. The method of claim 8, wherein the SS / PBCH block and the RMSI information are equal in time and terminate simultaneously.

10. The method of claim 2, wherein, A physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) are transmitted serially.

11. The method of claim 2, wherein, The PDCCH and the PDSCH are transmitted in parallel.

12. A base station, characterized by The base station comprises one or more processors, a storage unit and a communication interface, the one or more processors configured to perform the method of any one of claims 1 to 11.

13. A user equipment (UE), comprising: The UE comprises one or more processors, a storage unit and a communication interface, the one or more processors configured to decode the MIB transmitted as claimed in any one of claims 1 to 11.

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