Method and apparatus for control resource set configuration for common control

A user equipment (UE) for receiving control information in a wireless communication system includes a transceiver configured to receive a synchronization signal/physical broadcasting channel (SS/PBCH) block of an index i from a BS, wherein SS/PBCH block comprises a PBCH carrying master information block (MIB). The UE includes a processor configured to for the SS/PBCH block of the index i, determine a slot index n0 as a sum of an offset value and └i*M┘. The offset value is determined based on a first value O determined according to the index indicated in the MIB, wherein the index configures PDCCH monitoring occasions, and a second value μ indicated in the MIB, wherein the second value μ represents a subcarrier spacing configuration, wherein M is a positive number determined according to the index indicated in the MIB, and cause the transceiver to decode a PDCCH in the slot index n0.

TECHNICAL FIELD

The present application relates to configuring control resource set for common and/or specific control information in next generation wireless communication systems.

BACKGROUND

5th generation (5G) mobile communications, initial commercialization of which is expected around 2020, is recently gathering increased momentum with all the worldwide technical activities on the various candidate technologies from industry and academia. The candidate enablers for the 5G mobile communications include massive antenna technologies, from legacy cellular frequency bands up to high frequencies, to provide beamforming gain and support increased capacity, new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services/applications with different requirements, new multiple access schemes to support massive connections, and so on. The International Telecommunication Union (ITU) has categorized the usage scenarios for international mobile telecommunications (IMT) for 2020 and beyond into 3 main groups such as enhanced mobile broadband, massive machine type communications (MTC), and ultra-reliable and low latency communications. In addition, the ITC has specified target requirements such as peak data rates of 20 gigabit per second (Gb/s), user experienced data rates of 100 megabit per second (Mb/s), a spectrum efficiency improvement of 3λ, support for up to 500 kilometer per hour (km/h) mobility, 1 millisecond (ms) latency, a connection density of 106 devices/km2, a network energy efficiency improvement of 100λ and an area traffic capacity of 10 Mb/s/m2. While all the requirements need not be met simultaneously, the design of 5G networks may provide flexibility to support various applications meeting part of the above requirements on a use case basis.

SUMMARY

The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-Generation (4G) communication system such as long term evolution (LTE). Embodiments of the present disclosure provide multiple services in advanced communication systems.

In one embodiment, a user equipment (UE) for receiving control information in a wireless communication system is provided. The UE includes a transceiver configured to receive a synchronization signal/physical broadcasting channel (SS/PBCH) block of an index i from a base station (BS), wherein SS/PBCH block comprises a PBCH carrying master information block (MIB), and a processor configured to, for the SS/PBCH block of the index i, determine a slot index n0as a sum of an offset value and └i*M┘, wherein the offset value is determined based on: a first value O determined according to an index indicated in the MIB, pdcch-ConfigSIB1, wherein the index configures physical downlink control channel (PDCCH) monitoring occasions; and a second value μ indicated in the MIB, wherein the second value μ represents a subcarrier spacing configuration, wherein M is a positive number determined according to pdcch-ConfigSIB1; and cause the transceiver to decode a PDCCH in the slot index n0.

In a second embodiment, a base station (BS) for transmitting control information in a wireless communication system is provided. The BS includes a processor configured to, for a synchronization signal/physical broadcasting channel (SS/PBCH) block of an index i, configure a slot index n0as a sum of an offset value and └i*M┘, wherein SS/PBCH block comprises a PBCH carrying master information block (MIB), wherein the offset value is determined based on: a first value O determined according to an index indicated in the MIB, pdcch-ConfigSIB1, wherein the index configures physical downlink control channel (PDCCH) monitoring occasions, and a second value μ indicated in the MIB, wherein the second value μ represents a subcarrier spacing configuration, wherein M is a positive number determined according to the pdcch-ConfigSIB1, and a transceiver configured to transmit the SS/PBCH block of the index i, and a PDCCH in the slot index n0to a user equipment (UE).

In a third embodiment, a method for receiving control information in a wireless communication system is provided. The method includes receiving a synchronization signal/physical broadcasting channel (SS/PBCH) block of an index i from a base station (BS), wherein SS/PBCH block comprises a PBCH carrying master information block (MIB), and for the SS/PBCH block of the index i, determining a slot index n0, as a sum of an offset value and └i*M┘, wherein the offset value is determined based on: a first value O determined according to an index indicated in the MIB, pdcch-ConfigSIB1, wherein the index configures physical downlink control channel (PDCCH) monitoring occasions; and a second value μ indicated in the MIB, wherein the second value μ represents a subcarrier spacing configuration, wherein M is a positive number determined according to the pdcch-ConfigSIB1; and cause a transceiver to decode a PDCCH in the slot index n0.

DETAILED DESCRIPTION

To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a “beyond 4G network” or a “post LTE system.”

The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission coverage, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques and the like are discussed in 5G communication systems.

In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul communication, moving network, cooperative communication, coordinated multi-points (CoMP) transmission and reception, interference mitigation and cancellation and the like.

In the 5G system, hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an adaptive modulation and coding (AMC) technique, and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

According to the legacy long term Evolution® (LTE®) specification, relative received signal strength (RSSI) measurement is performed on Orthogonal frequency-division multiplexing (OFDM) symbols containing CRS if no other indication is provided; and on the DL part of measurement subframes, if measurement subframes are higher-layer configured.

In SS-block based Reference Signal Received Quality (RSRQ) measurement in NR, the direct extension of the method for first case, i.e., “no indication is provided,” could be to use the OFDM symbols with SS blocks. However, the OFDM symbols with SS bocks do not provide good representative of the frequency loading condition. Hence, an alternative mechanism for the first case may be necessary.

According to the NR agreements, the UE will know the downlink (DL) part of the subframes via cell-specific RRC configuration (SIB). One possible implication is that one could attempt to design the RSSI measurement resource purely based on the cell-specific indications to keep ensured that the measurement is performed on the DL part only. However, it is noticed that this UL/DL composition information is cell-specific, not carrier specific or cell-common. As RSRQ measurements requires knowledge of neighbor cell's UL/DL composition, the information is insufficient to let UE know the UL/DL compositions of the neighbor cell's UL/DL composition; the information is insufficient for RSRQ measurements for the neighbor cells if the measurement has to be performed on the “actual” DL part only, which could to be cell-specific.

For defining RSSI measurement resource in NR, there are two alternatives—either to define the RSSI measurement resource (Alt 1) without considering whether the resource is DL or UL or both, or only (Alt 2) the DL part of the resource. Alt 1 and Alt 2 have their its own pros and cons, and it is hard to decide one over the other.

One solution is to pre-configure or configure RSSI measurement resource (RMR), and ensure that the RMR is always downlink. To ensure this, the network is not allowed to overwrite the transmission direction to UL. If the network indicates that the transmission direction is uplink (UL) for the RMR, the RMR configuration is prioritized (or supersedes) or the network configuration of transmission direction is overridden by the RMR configuration. UE shall assume that the RMR portion of slot/frame is DL, despite the transmission direction configuration is UL.

Furthermore, the RMR may be explicitly configured in a frequency carrier specific information element carried in SIBx.

When RMR configuration supersedes the transmission direction configuration, and the RMR configuration is carrier specific, the RSSI measurement can be performed only in the DL part.

The RMR can be configured in terms of periodicity, offset and duration similarly to SMTC.

Alternatively, the RMR can be configured as only a time offset, to the starting point of each SMTC duration.

Alternatively, the RMR can be configured as time offset (relative to the starting point of each SMTC duration) and periodicity (e.g., in terms of a multiple of the SMTC periodicity like 1×, 2×, 4×, [½×, ¼×], etc.). The advantage of this alternative is that the channel direction overriding due to RMR can be configured to happen less frequently, which may increase network flexibility of UL/DL configuration.

It may be beneficial if the network has freedom to choose whether to use this overriding behavior or not. Hence, another proposal is:

UE can be indicated whether to over-ride the channel direction configuration with the RMR configuration or not.

If the over-riding is indicated or pre-configured, the user equipment (UE) will assume that RMR is always DL despite the channel direction configuration; UE will not expect to receive UL grant or configuration to transmit PUSCH/PUCCH in RMR, and/or UE shall rate match around the RMR portion if the UE receives a UL grant or configuration whose physical uplink shared channel (PUSCH)/physical uplink control channel (PUCCH) resource allocation includes the RMR. This is referred to “UE behavior 1.”

If the over-riding is turned off, the UE will assume that the RMR can also be UL; and hence the UE shall transmit PUSCH/PUCCH in the RMR. When the UE is indicated to transmit PUSCH/PUCCH in a part of RMR duration, the UE cannot use them to measure RSSI. This is referred to “UE behavior 2.”

If this overriding configuration is introduced, a default UE behavior will be necessary. The default behavior could be either, given that there are different pros and cons of these two UE behaviors.

This UL behavior on UL transmissions and RSSI measurements may also need to consider SS burst set composition indication which could be given by either RRC or RMSI (i.e., SIB1).

The UL/DL configuration may indicate that time-frequency resource corresponding to an SS block is UL. If the SS block is turned off in both the radio resource control (RRC) and RMSI indicated SS burst set composition, there is not contradicting information. However, it could happen that the SS block is turned on in RRC, RMSI or a separate indication for mobility measurement, but the UL/DL configuration indicates that the resource for the SS block is UL.

During the SMTC window duration in which UE performs measurement on SS blocks based on one of the SSB composition indications, the UL transmissions should be overridden to ensure that the UE performs measurement (i.e., the UL transmissions need to be dropped or rate matched around on the indicated SSB OFDM symbols). On the other hand, outside the SMTC window duration in which UE receives UL/DL data, it could be allowed so that the UE transmits PUSCH/PUCCH on an SS block which is turned on by the indication (i.e., the SMTC configuration is overridden and transmission direction configuration is prioritized).

Alternatively, to ensure that the SS blocks are received without UL interference to all the UEs in the cell, UE always prioritize the SSB composition indication over the UL/DL composition indication. If there is any collision between UL transmission and SSB reception according to the SSB composition indication, the UE shall drop the UL transmissions, or rate match around the UL transmissions around the whole SSB OFDM symbols according to the union of the SSB sets (corresponding to two SSB set composition indications by RMSI, RRC; and maybe another indication for mobility measurement purpose).

Alternatively, the UE behavior of transmitting UL signals on turned-on SSBs may further be controlled based on the type of SSB composition indication. For example, outside the SMTC window duration, the UE transmits UL signals on a “turned-on” SSB OFDM symbols based on RMSI indication or mobility measurement purpose indication of the SSB set composition, but the UE is not allowed to transmit UL signals on any of the “turned-on” SSB OFDM symbols based on RRC indication of the SSB set composition.

As shown inFIG. 1, the wireless network includes an eNB101, an eNB102, and an eNB103. The eNB101communicates with the eNB102and the eNB103. The eNB101also communicates with at least one network130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

The eNB102provides wireless broadband access to the network130for a first plurality of UEs within a coverage area120of the eNB102. The first plurality of UEs includes a UE111, which may be located in a small business (SB); a UE112, which may be located in an enterprise (E); a UE113, which may be located in a WiFi hotspot (HS); a UE114, which may be located in a first residence (R); a UE115, which may be located in a second residence (R); and a UE116, which may be a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB103provides wireless broadband access to the network130for a second plurality of UEs within a coverage area125of the eNB103. The second plurality of UEs includes the UE115and the UE116. In some embodiments, one or more of the eNBs101-103may communicate with each other and with the UEs111-116using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques.

Dotted lines show the approximate extents of the coverage areas120and125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with eNBs, such as the coverage areas120and125, may have other shapes, including irregular shapes, depending upon the configuration of the eNBs and variations in the radio environment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs111-116include circuitry, programing, or a combination thereof, for system information delivery in an advanced wireless communication system. In certain embodiments, and one or more of the eNBs101-103includes circuitry, programing, or a combination thereof, for efficient system information delivery in an advanced wireless communication system.

AlthoughFIG. 1illustrates one example of a wireless network, various changes may be made toFIG. 1. For example, the wireless network could include any number of eNBs and any number of UEs in any suitable arrangement. Also, the eNB101could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network130. Similarly, each eNB102-103could communicate directly with the network130and provide UEs with direct wireless broadband access to the network130. Further, the eNBs101,102, and/or103could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

FIG. 2illustrates an example eNB102according to embodiments of the present disclosure. The embodiment of the eNB102illustrated inFIG. 2is for illustration only, and the eNBs101and103ofFIG. 1could have the same or similar configuration. However, eNBs come in a wide variety of configurations, andFIG. 2does not limit the scope of this disclosure to any particular implementation of an eNB.

AlthoughFIG. 2illustrates one example of eNB102, various changes may be made toFIG. 2. For example, the eNB102could include any number of each component shown inFIG. 2. As a particular example, an access point could include a number of interfaces235, and the controller/processor225could support routing functions to route data between different network addresses. As another particular example, while shown as including a single instance of TX processing circuitry215and a single instance of RX processing circuitry220, the eNB102could include multiple instances of each (such as one per RF transceiver). Also, various components inFIG. 2could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

The processor340is also capable of executing other processes and programs resident in the memory360, such as processes for system information delivery in an advanced wireless communication system. The processor340can move data into or out of the memory360as required by an executing process. In some embodiments, the processor340is configured to execute the applications362based on the OS361or in response to signals received from eNBs or an operator. The processor340is also coupled to the I/O interface345, which provides the UE116with the ability to connect to other devices, such as laptop computers and handheld computers. The I/O interface345is the communication path between these accessories and the processor340.

FIG. 4Ais a high-level diagram of transmit path circuitry. For example, the transmit path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication.FIG. 4Bis a high-level diagram of receive path circuitry. For example, the receive path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication. InFIGS. 4A and 4B, for downlink communication, the transmit path circuitry may be implemented in a base station (eNB)102or a relay station, and the receive path circuitry may be implemented in a user equipment (e.g. user equipment116ofFIG. 1). In other examples, for uplink communication, the receive path circuitry450may be implemented in a base station (e.g. eNB102ofFIG. 1) or a relay station, and the transmit path circuitry may be implemented in a user equipment (e.g. user equipment116ofFIG. 1).

In transmit path circuitry400, channel coding and modulation block405receives a set of information bits, applies coding (e.g., LDPC coding) and modulates (e.g., quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) the input bits to produce a sequence of frequency-domain modulation symbols. Serial-to-parallel block410converts (i.e., de-multiplexes) the serial modulated symbols to parallel data to produce N parallel symbol streams where N is the IFFT/FFT size used in the BS102and the UE116. Size N IFFT block415then performs an IFFT operation on the N parallel symbol streams to produce time-domain output signals. Parallel-to-serial block420converts (i.e., multiplexes) the parallel time-domain output symbols from Size N IFFT block415to produce a serial time-domain signal. Add cyclic prefix block425then inserts a cyclic prefix to the time-domain signal. Finally, up-converter430modulates (i.e., up-converts) the output of add cyclic prefix block425to RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before conversion to RF frequency.

Each of eNBs101-103may implement a transmit path that is analogous to transmitting in the downlink to user equipment111-116and may implement a receive path that is analogous to receiving in the uplink from user equipment111-116. Similarly, each one of user equipment111-116may implement a transmit path corresponding to the architecture for transmitting in the uplink to eNBs101-103and may implement a receive path corresponding to the architecture for receiving in the downlink from eNBs101-103.

5G communication system use cases have been identified and described. Those use cases can be roughly categorized into three different groups. In one example, enhanced mobile broadband (eMBB) is determined to do with high bits/sec requirement, with less stringent latency and reliability requirements. In another example, ultra reliable and low latency (URLL) is determined with less stringent bits/sec requirement. In yet another example, massive machine type communication (mMTC) is determined that a number of devices can be as many as 100,000 to 1 million per km2, but the reliability/throughput/latency requirement could be less stringent. This scenario may also involve power efficiency requirement as well, in that the battery consumption may be minimized as possible.

FIG. 5illustrates a network slicing500according to embodiments of the present disclosure. An embodiment of the network slicing500shown inFIG. 5is for illustration only. One or more of the components illustrated inFIG. 5can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. Other embodiments are used without departing from the scope of the present disclosure.

As shown inFIG. 5, the network slicing500comprises an operator's network510, a plurality of RANS520, a plurality of eNBs530a,530b, a plurality of small cell base stations535a,535b, a URLL slice540a, a smart watch545a, a car545b, a, truck545c, a smart glasses545d, a power555a, a temperature555b, an mMTC slice550a, an eMBB slice560a, a smart phone (e.g., cell phones)565a, a laptop565b, and a tablet565c(e.g., tablet PCs).

The operator's network510includes a number of radio access network(s)520—RAN(s)—that are associated with network devices, e.g., eNBs530aand530b, small cell base stations (femto/pico eNBs or Wi-Fi access points)535aand535b, etc. The operator's network510can support various services relying on the slice concept. In one example, four slices,540a,550a,550band560a, are supported by the network. The URLL slice540ato serve UEs requiring URLL services, e.g., cars545b, trucks545c, smart watches545a, smart glasses545d, etc. Two mMTC slices550aand550bserve UEs requiring mMTC services such as power meters and temperature control (e.g.,555b), and one eMBB slice560arequiring eMBB serves such as cells phones565a, laptops565b, tablets565c.

In short, network slicing is a scheme to cope with various different qualities of services (QoS) in the network level. For supporting these various QoS efficiently, slice-specific PHY optimization may also be necessary. Devices545a/b/c/d,555a/bare565a/b/cexamples of user equipment (UE) of different types. The different types of user equipment (UE) shown inFIG. 5are not necessarily associated with particular types of slices. For example, the cell phone565a, the laptop565band the tablet565care associated with the eMBB slice560a, but this is just for illustration and these devices can be associated with any types of slices.

One device is configured with more than one slice. In one embodiment, the UE, (e.g.,565a/b/c) is associated with two slices, the URLL slice540aand the eMBB slice560a. This can be useful for supporting online gaming application, in which graphical information are transmitted through the eMBB slice560a, and user interaction related information are exchanged through the URLL slice540a.

In the current LTE standard, no slice-level PHY is available, and most of the PHY functions are utilized slice-agnostic. A UE is typically configured with a single set of PHY parameters (including transmit time interval (TTI) length, OFDM symbol length, subcarrier spacing, etc.), which is likely to prevent the network from (1) fast adapting to dynamically changing QoS; and (2) supporting various QoS simultaneously.

It is noted that “slice” is a terminology introduced just for convenience to refer to a logical entity that is associated with common features, for example, numerology, an upper-layer (including medium access control/radio resource control (MAC/RRC)), and shared UL/DL time-frequency resources. Alternative names for “slice” include virtual cells, hyper cells, cells, etc.

FIG. 6illustrates a number of exemplary digital chains600according to embodiments of the present disclosure. An embodiment of the number of digital chains600shown inFIG. 6is for illustration only. One or more of the components illustrated inFIG. 6can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. Other embodiments are used without departing from the scope of the present disclosure.

For mmWave bands, the number of antenna elements can be large for a given form factor. However, the number of digitally chain to be limited due to hardware constraints (such as the feasibility to install a large number of ADCs/DACs at mmWave frequencies) as illustrated inFIG. 6. In this case, one digital chain is mapped onto a large number of antenna elements which can be controlled by a bank of analog phase shifters. One digital chain can then correspond to one sub-array which produces a narrow analog beam through analog beamforming. This analog beam can be configured to sweep across a wider range of angles by varying the phase shifter bank across symbols or subframes.

Several embodiments to transmit the minimum system information transmission in an advanced communication are provided in the present disclosure.

In some embodiments, RMSI is transmitted via other channels at least partially indicated by NR-PBCH. In one example, the NR-PBCH carries a part of minimum system information including information necessary for the UE to receive channel carrying RMSI. In another example, the NR-PBCH carries information necessary for the UE to perform initial UL transmission (not limited to NR-PRACH, e.g. PRACH msg. 1) and possibly information necessary to receive the response to initial UL transmission (e.g., PRACH msg. 2) in addition to information in the aforementioned example.

In some embodiments, RMSI is transmitted via other channels not indicated in the NR-PBCH. In one example, the NR-PBCH carries information necessary for the UE to perform initial UL transmission (not limited to NR-PRACH, e.g. PRACH msg. 1) and information necessary to receive the response to initial UL transmission (e.g. PRACH msg. 2). In such example, information necessary to receive RMSI is provided after initial UL transmission.

In some embodiments, the NR-PBCH carries all of minimum system information.

In the LTE specifications, an MIB is periodically broadcast with 40 msec periodicity, SIB-1 is periodically broadcast with 80 msec periodicity, and SIB-2 is also periodically broadcast, whose periodicity is configured by SIB-1.

The MIB uses a fixed schedule with a periodicity of 40 ms and repetitions made within 40 ms. The first transmission of the MIB is scheduled in subframe #0 of radio frames for which the SFN mod 4=0, and repetitions are scheduled in subframe #0 of all other radio frames. For time division duplex/frequency division duple (TDD/FDD) system with a bandwidth larger than 1.4 MHz that supports BL UEs or UEs in CE, MIB transmission may be repeated in subframe #9 of the previous radio frame for FDD and subframe #5 of the same radio frame for TDD.

This disclosure provides configuration/indication of CORESETs for receiving common control channels, such as RMSI, OSI, system information block x (SIBx), random access response (RAR), etc. CORESET configuration is provided via PBCH (or MIB) for at least RMSI scheduling, and another CORESET configuration is provided via RMSI (or SIB1) for at least RAR scheduling. In this disclosure, RMSI refers to SystemInformationBlock1 (SIB1).

A CORESET (control resource set) may be characterized by a slot timing, OFDM symbol numbers in each slot, and frequency resources. These CORESET properties are indicated or pre-configured for each CORESET. For RMSI/SIB scheduling, the CORESET properties are provided in the PBCH. For RAR scheduling, the CORESET properties are provided in the RMSI.

Among these CORESET properties configured by PBCH/RMSI, the OFDM symbol numbers and frequency resources are commonly applicable to all the common channels (e.g., SIBx/RAR, etc.), but the slot timing is specifically determined/indicated for different SIBx/RAR.

In some embodiments, PBCH indicates the following information for the CORESET: #1) frequency resources; #2) OFDM symbol numbers in each slot; and #3) RMSI slot timing e.g., in terms of slot offset and periodicity. Information #1 and #2 can be reused for type 0 CSS, i.e., at least for SIBx transmissions for x>1. Information #3 provided in the PBCH is used only for RMSI transmissions; the slot timing for other SIBx (x>1) is separately indicated. If the LTE principle is reused, the SIB2 slot timing is configured by RMSI, and the rest of the SIBx slot timings are indicated in SIB2.

The type 0 CSS CORESETs characterized by information #1) and #2) can be used for paging and/or RAR as well, along with separately optimizing the slot timing, for reducing specification efforts.

In one embodiment, PBCH indicates the following information for CORESET(s): 1) frequency resources, 2) OFDM symbol numbers in each slot, and 3) slot timing (e.g., in terms of slot offset and periodicity). Information 1) and 2) are commonly used for OSI and/or paging and/or RAR transmissions, while information 3) is applicable only for RMSI. For OSI (SIBx, x>1), paging, RAR, information 3) is individually determined or indicated.

To configure the multiple CORESETs efficiently with small signaling payload in PBCH, one possible approach is to configure as many common parameters for all the CORESETs as possible. Among the three information elements discussed in an embodiment of this disclosure, information #1) frequency resources can be made common for all the CORESETs (and the common information is indicated in PBCHs of all the SSBs of a cell). On the other hand, it may be necessary to allow for different slot & OFDM symbol timings (i.e., information #2 and #3) for multiplexing the CORESETs in a TDM manner; in this case different information for #2 and #3 may be indicated in PBCHs of different SSBs.

For indicating the timing information, two alternatives can be provided. In a first alternative, each PBCH in an SS burst set contains only common information to configure the multiple CORESETs. The timing of the CORESET to be monitored upon detecting an SSB may be derived with the commonly signaled information and the SSB index. In a second alternative, a PBCH of an SSB in an SSB set contains both common and specific information to configure a CORESET that is QCL'ed with the SSB containing the PBCH. The specific information can be used to further adjust the CORESET timing corresponding to the SSB, thereby more network flexibility can be achieved than the first alternative.

The first alternative may provide more robustness, and allows easier beam switching during the initial cell selection and IDLE mode. If there are PBCHs with the same contents within/across SSBs, UE may be able to soft combine the PBCHs to achieve more reliability. When the UE switches to select another SSB beam due to intra-cell mobility, the UE can figure out an updated CORESET location just relying on the previously decoded MIB, i.e., the UE does not need to decode another MIB in the newly selected SSB again.

The second approach provides more flexibility to the network, but for IDLE mode intra-cell mobility, UE may need to acquire the “specific” information to find the CORESET corresponding to a newly selected SSB than the initially detected SSB. It would not be desirable if UE has to decode a PBCH in the newly selected SSB to acquire the specific information. A better alternative could be the specific information for all the SSBs of a cell is provided cell-specifically in SIBx, so that the UE can identify all the CORESET timing locations of a cell without having to decode individual PBCH. In some embodiments, the specific information is referred to “information about SSB-specific offset”, or Δss.

In one embodiment, the timing information can be configured according to one of the following two alternatives. In the first alternative, A PBCH in an SSB contains full information to configure all the CSS CORESETs in the cell. The timing of the CORESET corresponding to the selected SSB may be derived with the signaled information and the SSB index. In a second alternative, a PBCH in an SSB contains common information to be used for all the CSS CORESETs in the cell; and also specific information to be used for identifying the location of a CORESET that corresponds to (or is QCL'ed with) the SS block containing the PBCH. The specific information can be used to further adjust the CORESET timing corresponding to the SSB, thereby more network flexibility can be achieved than the first alternative.

To minimize fragmentation of the resources, it is desirable to confine these signals to be transmitted with the MIB configured numerology, i.e., MIB configured CORESET, RMSI, RMSI configured CORESET, msg 2/4 for initial access, broadcast OSI, etc., in a localized time-frequency resource. In particular, for the frequency domain, the BW to transmit these signals could comprise a single BW whose BW size is less than the UE minimum BW. Now the remaining issue is whether to additionally support configuration of the single BW separately from the UE minimum BW which encompassing the SS block BW, i.e., whether NR supports FDM between SS block and CORESET/PDSCH. The main arguments to support FDM from an operator was that the OFDM symbols used for SS blocks may not be so useful for any other purposes, if the TRP of a cell has a single TXRU and analog BF constraints are in place; and it may be useful to allow the FDM so that the broadcast information of RMSI can be FDM'ed with the SS blocks in those OFDM symbols. This seems to be a valid argument, and it would be good to address this operator's concern if there is a simple way to support the FDM.

The FDM can be supported by allowing to configure the frequency location for the single BW in terms of frequency offset to the SS block BW. If the candidate frequency offset values to be indicated in the MIB includes ‘0’ and other values corresponding to BWPs non-overlapping with the SS block BW, then both TDM and FDM of the SS block and the single BW will naturally be supported.

Regarding the FDM in addition to TDM of RMSI and SS block, the FDM may require UE to re-tune the RF to receive the RMSI, especially when the aggregated BW of the RMSI and SS block exceeds “UE minimum BW.”

FIG. 7Aillustrates an exemplary initial access process for eMBB UE, andFIG. 7Billustrates an exemplary initial access procedure for a minimum capability UE, according to embodiments of the present disclosure. The embodiments shown inFIGS. 7A and 7Bare for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Different UEs can support different BWs as a UE capability, and there can be UEs to support only the minimum channel BW for a specific band, e.g., 5 MHz, such as eMTC UEs in LTE. However, it is expected that eMBB UEs are likely to be able to support larger than UE minimum BW. If the combined BW of RMSI and SS block is within 50 PRBs, eMBB UEs are likely to be able to support reception of both RMSI and SS block using a single RF, and correspondingly the frequent RF re-tuning is not likely to be necessary. The minimum capability UEs, however, may have to perform RF retuning to receive SS block and other signals in different BWs. This RF re-tuning operation has been supported for LTE eMTC, and it hence does not seem to be an issue to mandate the RF re-tuning for minimum capability UEs.

For facilitating minimum capability UE's reception of SSBs and other initial access signals, it could be considered such that the intra-frequency SMTC configuration (i.e., periodicity, offset and duration) is provided in the early stage of initial access, e.g., RMSI or SIBx. For the minimum capability UEs, the intra-frequency SMTC duration may be regarded as measurement gap, similarly to the legacy inter-frequency case.

It is noted that BWP is a UE specific concept. Effectively, a UE with minimum capability will see initial active BWP of 25 PRBs corresponding to the BW carrying RMSI, RAR and Open System Interconnection (OSI), and an eMBB UE will see initial active BWP of 50 PRBs, corresponding to the aggregated BW of SSB BW and RMSI/RAR/OSI BW.

When the combined BW size of SSB and RMSI is about 50 PRBs: UEs supporting more than 50-PRB maximum channel bandwidth do not need to perform RF retuning; and UEs supporting only minimum channel BW needs to perform RF retuning for TDM reception of SS blocks and other signals. To facilitate UE's TDM reception of SS blocks, SMTC configuration may be provided early, e.g., in RMSI. The SMTC duration may be regarded as measurement gap.

In one embodiment, an initial-active BW is configured in MIB by means of a frequency offset. The initial-active BW is to transmit these signals according to the MIB configured numerology, i.e., MIB configured CORESET, RMSI, RMSI configured CORESET, msg 2/4 for initial access, broadcast OSI, and the like. The candidate values to indicate the frequency offset include at least {0, +25, −25} PRBs, so that the combined BW of SS block and the initial-active BW is minimized. The number of bits for the frequency offset is limited to 2 bits.

Configuration of CORESET Burst Set Parameters for CSS

Values of some parameters for configuring CORESETs for CSS are fixed, and values of some other parameters are indicated in the MIB.

Frequency information parameters may include number of PRBs (e.g., BW) for CORESETs for CSS and the frequency location in a minimum carrier BW. Note that it is desirable to confine and configure CORESETs for CSS within a minimum carrier BW to avoid too many retuning by the UE. This configuration is likely to be common across all the SS blocks, and includes the following information contents. The number of PRBs (e.g., BW): Given that the minimum carrier BWs are 5 MHz (for below 6 GHz) and 50 MHz (for below 6 GHz), the candidate PRB allocation for the CORESET would be limited or even further fixed to the minimum carrier BW. To save signalling overhead, it is proposed to use a fixed BW of 25 PRBs. Frequency location: a 2-bit information is used to indicate a PRB offset for the CORESET/RMSI and other signals with respect to the SS block frequency.

Timing information parameters may include periodicity, slot location, OFDM symbol numbers. The information contents are summarized below.

Periodicity: For the CSS, the periodicity does not need to be explicitly configured in PBCH. It is noted that for individual SIBx, this periodicity and SSB-common slot offset can be signalled or predefined in the spec.

Slot location: The CSS CORESETs may come as a burst set similarly to SSB set, and each CSS CORESET slot location corresponding to SSB isscan be determined as ns=ocommon+ƒ(nss, iss, Δss). Here, the notation ƒ(nss, iss, Δss) implies that the resulting value of ƒ(nss, iss, Δss) is at least partly dependent upon at least one of nss, iss, Δss. ocommon: a common offset for all the CSS CORESETs (i.e., starting slot number of the CSS CORESET burst set), may be configured in RMSI/OSI, which could be frame, half-frame starting boundary or a slot starting boundary. Note that ocommonfor RMSI CORESETs (i.e., oRMSI) needs to be provided in PBCH or predefined in the spec. iss: SSB index, i.e., 0, 1, . . . , L−1, where L is determined band specifically. nss: Slot number to map SSB iss, where the slot number is defined according to the SSB numerology. Δss: information about SSB-specific offset provided in the PBCH. The value of this parameter may be SSB specific, i.e., different values may be indicated in different SSBs.

OFDM symbol indices: OFDM symbols in a slot for a CORESET that should be monitored when UE detects an SSB iss. The symbol indices need to be indicated in MIB. The OFDM symbol indices may be determined depending at least partly on number of CORESETs per slot and the SSB & RMSI numerology/SCS. The number of CORESETs to be mapped per slot can be one or two [or four), which could be signaled in the PBCH. The decision of the number of CORESETs per slot is network implementation issue, and the NW will determine the number with considering the support of FDM and TDM of RMSI and SS blocks, and the support of slot-based and non-slot based transmissions.

CCE-to-REG mapping: fixed to ‘interleaved’ only (i.e., no configuration is needed).

REG bundling size: Fixed to be 6.

DMRS BW: Fixed to be WB-RS, i.e., according to option ii) as follows. For a CORESET, precoder granularity in frequency domain is Configurable between option i) equal to the REG bundle size in the frequency domain; or option ii) equal to the number of contiguous RBs in the frequency domain within the CORESET. For option ii), DMRS is mapped over all REGs within the CORESET.

Quasi-CoLocation (QCL): a CORESET corresponding to an SS block is QCL'ed to the SS block. The correspondence is indicated in the PBCH by means of the RMSI CORESET signaling.

PDSCH resource mapping type (slot vs. non-slot): implicitly configured by the number of configured CORESETs per slot. If one, slot-based transmission; if two or more, non-slot based transmissions. The number of configured CORESETs per slot can be implicitly/explicitly indicated in the PBCH.

Configuration of CORESET Burst Set Parameters for RMSI

Frequency information is same as CORESETs for CSS. No additional configuration is necessary.

Timing information includes a periodicity and number of repetitions within RMSI TTI, slot location and OFDM symbol indices.

A periodicity and number of repetitions within RMSI TTI (Timing information): a mini-slot or a full-slot can be used for RMSI PDSCH transmissions. This results in more than 2× coding rate variations on PDSCH used for RMSI, and hence it is necessary to allow variable number of repetitions to support worst case coverage.

FIGS. 8A and 8Billustrates exemplary methods of signaling of variable number of repetitions to fulfil a desired coverage according to embodiments of the present disclosure. The embodiments shown inFIGS. 8A and 8Bare for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

In the method1as illustrated inFIG. 8A, variable numbers of CORESET burst sets (e.g., 4 or 8 repetitions or burst sets) are mapped in a fixed RMSI TTI duration (e.g., 80 msec). The resulting RMSI duty cycles will be 10 and 20 msec, respectively for 8 and 4 repetitions.

In the method2as illustrated inFIG. 8B, RMSI TTI duration scales with the number of repetitions (e.g., 4 or 8 repetitions), while the RMSI duty cycle is kept the same (e.g., 20 msec). The resulting RMSI TTI durations will be 80 and 160 msec respectively for 4 and 8 repetitions.

Slot location (Timing information) can be determined as ns=oRMSI+ƒ(nss, iss, Δss). oRMSI∈{0, o1, o2, . . . }, for example, where o1could corresponds to the number of slots in a half frame according to the configured RMSI numerology. Note that here ocommonfor CSS corresponds to oRMSI. When oRMSI=0, the RMSI and SS blocks are mapped in FDM manner; or when FDM is signalled, UE shall assume oRMSI=0. Depending on how many CORESETs are mapped per slot, different function ƒ(nss, iss, Δss) may be used. It is expected that either one or two CORESETs can be mapped per slot, considering the support of FDM and TDM of RMSI and SS blocks, and also the support of slot-based and non-slot based transmissions. The intention to introduce SSB specific Δssis to allow possibility of assigning a same CORESET for differently indexed SSBs. For example, SSB 0 and 1 points to the same CORESET by utilizing the delta offset. This provides a mechanism to allow number of CORESETs in the CORESET burst set to be smaller than the number of SSBs in the SSB set.

OFDM symbol indices (Timing information): can be determined as a function of at least one of numerology, number of CORESETs per slot, iss, and Δss. The number of OFDM symbols can be jointly determined with the RMSI CORESET BW, to be able to configure 48 or 96 REGs. The starting OFDM symbol may be determined as a function of at least one of the RMSI numerology, the SSB numerology, number of CORESETs per slot, and iss. In particular FDM/TDM of RMSI PDSCH and SSB clearly affects the CORESET time domain mapping.

In some embodiments, the RMSI scheduling configuration is indicated according to TABLE 1.

FIG. 9illustrates an exemplary time domain mapping of the SSBs in a time unit according to one embodiment of the present disclosure. The embodiment shown inFIG. 9is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Whether the system utilizes the Frequency Division Multiplex (FDM) or Time Division Multiplex (TDM) may be indicated by means of oRMSIbeing 0 (FDM) or the number of slots corresponding to non-zero value (TDM) in the RMSI numerology.

If FDM, the time-domain mapping of RMSI PDSCH is aligned with the SS blocks, and a distinct CORESET will be assigned to an SS block, where the CORESET is QCL'ed with the SS block in a set of large scale parameters, including the spatial parameters.

If TDM, the timing-domain mapping of RMSI PDSCH/CORESETs can be more flexibly designed. As illustrated inFIG. 3, the length of time unit is 1 msec, for 15 and 30 kHz SCS, and the length of time unit is 0.25 msec, for 120 and 240 kHz. The SSB location in time domain is dependent upon the subcarrier spacing value. The shaded areas correspond to the SSB locations. For example, for 15 kHz SCS, OFDM symbols {2,3,4,5} and {8,9,10,11} are used for SSB mapping in a 14-symbol slot.

FIG. 10illustrates another exemplary time domain mapping of the SSBs in a time unit according to one embodiment of the present disclosure. The embodiment shown inFIG. 10is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Two or four time units are consecutively placed in time domain to map the full SSB set for a given carrier frequency and subcarrier spacing. The time unit mapping is illustrated inFIG. 4.

When the full SSBs are mapped (according to the value of L), up to 5 msec duration is occupied. Hence, a common offset value, oRMSI, that can always be used for TDM mapping is the slot number corresponding to 5 msec. If mapping of both SSBs and RMSIs in a same half-frame is desired, the slot number corresponding to 2 or 3 msec in the RMSI numerology can also be considered to be signaled. This second number may be necessary for 5 msec SSB periodicity and TDM is desired by the network. Similarly, the slot number corresponding to 7 or 8 msec in the RMSI numerology can also be considered.

Candidate values for oRMSI=0, (the slot number corresponding to 5 msec in the RMSI numerology), (the slot number corresponding to 2 or 3 msec in the RMSI numerology), (the slot number corresponding to 7 or 8 msec in the RMSI numerology).

In case of FDM mapping, one out of two candidate oRMSIvalues may be configured, one value is the value corresponding to o1=2 or 3 msec, and the other value is o2=5 msec. The candidate values for oRMSImay be specified in a numerology specific manner. One example is shown in Table 2.

An alternative table specifying the candidate values for oRMSIis shown in Table 3.

In some embodiments, at least one of (the number of CORESETs per slot), (slot number for the RMSI CORESET), oRMSI, and (OFDM symbol indices in the slot) are indicated jointly by a bit field conveyed in the PBCH as part of RMSI scheduling information. In some embodiments, the bit field is referred to as pdcch-ConfigSIB1. One example construction is shown in TABLE 4.

FromFIG. 9, it can be seen that the possible locations of the OFDM symbols for the CORESET mapping corresponding to an SSB is dependent upon the numerology. If FDM is used (e.g., by means of indicating oRMSI=0) for the RMSI and SS blocks, and the same numerology is used for the SSB and RMSI, the OFDM symbol numbers are determined as in TABLE 5.

If TDM is used, indication of slot and OFDM symbol locations for the CORESET burst set can be designed in a more flexible manner. However, fully flexible solution cannot be supported in NR, because of the constraints we have in the PBCH payload. In case full-slot scheduling is used, the number of CORESETs in a slot should be fixed to be one. The number of slots necessary to support the L CORESETs corresponding to L SSBs will be L slots in this case. Alternatively, when the non-slot based scheduling is used, e.g., with allocating two CORESETs per slot, the number of slots necessary to support the L CORESETs will be L/2 slots. This method could reduce the common search space CORESET overhead. In order to further reduce the common search space CORESET overhead, non-one-to-one correspondence of SSB and CORESET mapping should be supported. One way to achieve this is to indicate the SSB specific resource offset information Δss(iss) in the PBCH of each SSB. In one example, when Δss(iss)=0, the CORESET time locations are selected according to the one-to-one mapping rule between the SSBs and CORESETs. When Δss(iss)=0, the CORESET time locations for the even numbered issare selected according to the one-to-one mapping rule, while the COREST time locations for the odd numbered isswill be selected to be the time locations corresponding to iss−1, according to the one-to-one mapping rule. This way, the same CORESET resource is indicated by two different SSBs in consecutive SSB indices.

One example of one-to-one correspondence of SSB and CORESET timing in case of mapping a single CORESET per slot is described as in the following Slot number (in RMSI numerology) can be determined as ns=oRMSI+iss; in this case, ƒ(nss, iss, Δss)=iss. OFDM symbol numbers are fixed to be {0,1}.

One example of one-to-one correspondence of SSB and CORESET timing in case of mapping two (2 CORESETs per slot to be used for TDM case (i.e., oRMSIis non-zero) is described as in the following. Slot number (in RMSI numerology) can be determined as ns=oRMSI+floor(iss/2); in this case, ƒ(nss, iss, Δss)=floor(iss/2). Similarly, if N CORESETs per slot, ns=oRMSI+floor(iss/N), where N is an integer; OFDM symbol numbers are determined to be {0,1} fixed if issis even; or {2,3} fixed or alternatively {7,8} fixed if issis odd.

FIG. 11shows the slots mapped with the CORESET burst set when RMSI SCS is 15 or 30 kHz according to embodiments of the present disclosure. The embodiments shown inFIG. 11is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

InFIG. 11, the shaded slots are the ones mapped with the CORESET. The association of SSB index issto the slots are according to the ascending order. For example, according to the mapping corresponding to 15 kHz Alt 1 with one CORESET per slot, the CORESET corresponding to SSB4 is mapped to slot #4. According to the mapping corresponding to 15 kHz Alt 2 with one CORESET per slot, the CORESET corresponding to SSB4 is mapped to slot #5. According to the mapping corresponding to 15 kHz Alt 1 with two CORESETs per slot, the CORESET corresponding to SSB4 is mapped to slot #2.

FIG. 12shows the slots mapped with the CORESET burst set when RMSI SCS is 60 or 120 kHz according to embodiments of the present disclosure. The embodiments shown inFIG. 12is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

The shaded slots are the ones mapped with the CORESET. The same pattern may repeat up to X times, according to the number of CORESETs required for the SSB mapping.

The number of CORESETs per slot may be implicitly indicated by the ratio of the RMSI SCS to the SSB SCS if ocommon=0 (or the FDM is indicated). In case of FDM, the number of PDSCH symbols scheduled by the PDCCH may also be pre-configured in the spec, based on the ratio of RMSI SCS to SSB SCS.

Otherwise (i.e., ocommon>0 or if TDM is indicated), the number of CORESETs is separately indicated; and the number of PDSCH symbols scheduled by the PDCCH may be dynamically signaled in the DCI, or separately indicated in the PBCH.

FIGS. 13A, 13B, 13C and 13Dillustrate CORESET mappings for FDM'ed CORESET PDSCH with SSBs, according to some embodiments of the present disclosure. In particular,FIG. 13Aillustrates an FDM case of the CORESET mapping option 1—48/96 total PRBs,FIG. 13Billustrates an FDM case of the CORESET mapping option 1—24 total PRBs,FIG. 13Cillustrates an FDM case of the CORESET mapping option 2—48/96 total PRBs, andFIG. 13Dillustrates a FDM case of the CORESET mapping option 2—24 total PRBs. The embodiments shown inFIGS. 13A, 13B, 13C and 13Dare for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

A CORESET for the PDSCH which is FDM'ed with an SSB, should be located either prior to or before the set of OFDM symbols with SSB.

In option 1, the OFDM symbols prior to the OFDM symbols with the SSB are configured for the CORESET, as illustrated inFIGS. 7A and 7B. This option is applicable regardless of whether the system is coverage-limited or not, and whether same/different numerologies are used for the RMSI and SSB. The CORESET mapping inFIG. 7Aallows for at least 48 total PRBs in RMSI numerology. The mapping inFIG. 7Ballows for 24 total PRBs in RMSI numerology, and hence it can be less prioritized. In case where 240 kHz SCS is applied to SSB, the option 1 mapping is challenging, as only two OFDM symbols are available prior to 4 consecutive SSBs. One possibility is to map two CORESETs in each of these two OFDM symbol as illustrated in the figure.

In option 2, the OFDM symbols on a subset of OFDM symbols with the SSB are configured for the CORESET, as illustrated inFIGS. 7C and 7D. This option may be applicable if the network is willing to operate in a smaller coverage in exchange of potentially smaller overhead, and if the network can have a wide initial active BW (although it will be limited by the UE capability). To efficiently support the Option 2, it may be required that the UE assumes that the rest of the REs other than those used for the PDCCH mapping are available for PDSCH transmissions. In other words, when FDM'ed initial active BWP is configured, for receiving the RMSI PDSCH scheduled by the PDCCH, the UE shall rate match around only the time/frequency resources (e.g., PRBs) corresponding to the PDCCH REs conveying the RMSI PDSCH scheduling information; and assumes that all the other REs (if scheduled) are available for PDSCH data reception.FIG. 13DFDM case:

An example mapping of the number of CORESETs per slot and the number of PDSCH symbols to the RMSI SCS and the SSB SCS when FDM is indicated is illustrated in the TABLE 6A, for which Option 1 is assumed.

An example mapping of the number of CORESETs per slot and the number of PDSCH symbols to the RMSI SCS and the SSB SCS when FDM is indicated is illustrated in the TABLE 6B, for which Option 2 is assumed.

An example mapping of the number of CORESETs per slot to the number of PDSCH symbols when TDM is indicated is illustrated in the TABLE 6.

In some embodiments, the number of RMSI repetitions are determined as a function of the number of OFDM symbols for the PDSCH. It is noted that the number of OFDM symbols for the PDSCH may be determined according to the embodiments related to TABLE 5 or TABLE 6. One such example is illustrated in TABLE 7.

FIG. 14illustrates an exemplary SIBx CORESET transmission timing according to one embodiment of the present disclosure. The embodiment shown inFIG. 14is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

The CORESETs that are QCL'ed with different SSBs are TDM'ed. The UE who detects SSB i should be able to find the timing for CORESET i, which is QCL'ed with the SSB. UE can find the timing with jointly considering SSB index i and the commonly signalled PBCH contents.

An example construction of indication #5 is shown in TABLE 8C.

FIGS. 15A, 15BA and 15BBillustrate alternative SIBx CORESET transmission timings according to embodiments of the present disclosure. The embodiments shown in FIGS.15A,15BA and15BB are for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Given the very limited payload available in the PBCH to configure RMSI CORESETs and RMSI timing, some parameters need to be fixed in the specification, i.e., only essential information that are necessary to be informed for the UE to receive RMSI PDCCH/PDSCH needs to be included.

In order to deal with FDM and TDM mapping of RMSI and SSBs, it is necessary to make frequency domain mapping information (i.e., PRBs and frequency position) configurable. In addition, to cope with both mini-slot and non-mini slot mapping, and also to provide sufficient PDCCH coverage, it is also necessary to make the set of OFDM symbol indices for a CORESET configurable. In consideration of the multi-beam RMSI and mini-slot mapping, the CORESET OFDM symbols should be determined by using the common PBCH contents and SSB index jointly.

The RMSI timing configuration needs to be known at the UE when trying to decode RMSI. The timing configuration can be either fixed in the spec, or at least partially configured by the network, for network resource utilization flexibility/efficiency. As both mini-slots and full slots are agreed to be used for RMSI transmissions, hard-coded timing can be ruled out. The multi-beam RMSI mapping in time domain should take at least the mini-slot or full-slot mapping of RMSI; and the beam-specific RMSI timing needs to be conveyed via the SSB index. The OSI timing configuration should be done similar to RMSI timing configuration, i.e., some information conveyed via PBCH and SSB index should be jointly used.

Then, the rest of information does not seem to be essential to be made configurable, although this may imply that some system-operation flexibility might be lost. It is already challenging to indicate only those above information in the PBCH, given the maximum payload of [8] bits excluding the numerology indication.

FIG. 16is an exemplary diagram illustrating how RMSI CORESET parameters are configured according to one embodiment of the present disclosure. The embodiment shown inFIG. 16is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Frequency domain parameters are indicated via the common MIB contents.

The OFDM symbols and RMSI PDCCH monitoring windows are CORESET specific, and determined by the SSB index conveyed in the SSB and the common PBCH contents.

OSI (SIBx, x>1) PDCCH monitoring windows are determined CORESET specifically, by the SSB index conveyed in the SSB, the common PBCH contents and the RMSI contents.

The PDCCH DMRS of the CORESET i (for which some of those parameters are determined according to SSB index i) can be assumed to be QCL'ed with SSB i.

Time domain parameters include a set of OFDM symbol indices in a slot corresponding to a CORESET, and RMSI timing configuration (i.e., PDCCH monitoring occasions for RMSI).

SSBs are QCL'ed with CORESETs rather than search spaces. A CORESET can potentially be used for multiple sets of search spaces, e.g., for common and UE specific sets of search spaces. According to the decision, the CORESET timing does not need to be separately indicated, and the CORESET timing is determined as a union of the timing instances for the configured search spaces for the CORESET. It would be sufficient if PBCH can provide RMSI monitoring timing.

FIG. 17is another exemplary diagram illustrating how RMSI CORESET parameters are configured according to one embodiment of the present disclosure. The embodiment shown inFIG. 17is for illustration only. Other embodiments are used without departing from the scope of the present disclosure.

Frequency domain parameters, the number of CORESET OFDM symbols and a set of aggregation levels are indicated via the common MIB contents.

In the set of aggregation levels, 4, 8, [16] CCE aggregation levels should be supported (for ensuring the PDCCH coverage), and/or 48 and 96 total number of REGs should be supported (depending on FDM vs. TDM and available operator BW), where the number is determined implicitly by the indication of CORESET BW and number of OFDM symbols.

A starting position of the CORESET OFDM symbols, and RMSI PDCCH monitoring windows are CORESET specific, and determined by the SSB index conveyed in the SSB and the common PBCH contents.

OSI (SIBx, x>1) PDCCH monitoring windows are determined CORESET specifically, by the SSB index conveyed in the SSB, the common PBCH contents and the RMSI contents.

The PDCCH DMRS of the CORESET i (for which some of those parameters are determined according to SSB index i) can be assumed to be QCL'ed with SSB i.

FIG. 18illustrates an exemplary flow chart of a method1800for receiving control information in a wireless communication system, as may be performed by a UE, according to one embodiment of the present disclosure. The embodiment of the method1800shown inFIG. 18is for illustration only. One or more of the components illustrated inFIG. 18can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. Other embodiments are used without departing from the scope of the present disclosure.

As shown inFIG. 18, the method1800begins at step1810. In step1810, the UE receives a synchronization signal/physical broadcasting channel (SS/PBCH) block of an index i from a base station (BS). The SS/PBCH block comprises a PBCH carrying master information block (MIB).

In step1820, for the SS/PBCH block of the index i, the UE determines a slot index n0, as a sum of an offset value and └i*M┘. The offset value is determined based on a first value O and a second value μ. The first value O can be determined according to an index indicated in the MIB, pdcch-ConfigSIB1, in which the index configures physical downlink control channel (PDCCH) monitoring occasions. The second value μ can be indicated in the MIB, wherein the second value μ represents a subcarrier spacing configuration. Here, M is a positive number determined according to the pdcch-ConfigSIB1.

Subsequently, the UE in step1830performs PDCCH monitoring and decodes a PDCCH in the slot index n0.

None of the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined only by the claims. Moreover, none of the claims are intended to invoke 35 U.S.C. § 112(f) unless the exact words “means for” are followed by a participle.