Cell search procedure and initial bwp configuration for reduced capability ue devices

Abstract

A cell search procedure and initial BWP configuration for reduced capability UE devices is disclosed. A system and method for accommodating reduced capability user equipment in a mobile network. The method can include monitoring, by a bandwidth limited user equipment (UE), a subset of control resource sets (CORESETs), use of specific synchronization signals for bandwidth limited UEs, or use of bandwidth part (BWP) switching.

Description

[0001] This application claims priority and benefit to the following applications: (i) U.S. Provisional Application No. 63 / 013,391, filed April 21, 2020, entitled “Initial Access Procedure and Initial BWP Configuration for a Bandwidth-Limited NR Apparatus”, and (ii) U.S. Provisional Application No. 63 / 037,531, filed June 10, 2020, entitled “Initial Access Procedure and Initial BWP Configuration for a Bandwidth-Limited NR Apparatus”; the two applications identified in this paragraph are incorporated herein by reference. Technical Field

[0002] One or more aspects of embodiments of this disclosure relate to mobile communications, and more specifically to a system and method for accommodating degraded user equipment in a mobile communication network. Background Technology

[0003] In mobile communication networks, small, low-cost, or low-power user equipment (UE) may have useful applications. Such UEs can be more easily manufactured by reducing their capabilities compared to other UEs. However, unless such reduced capabilities are accommodated, in some cases, the reduction in capabilities may prevent the establishment of a connection between the network and the UE.

[0004] Therefore, a system and method are needed to accommodate degraded user equipment in mobile networks. Summary of the Invention

[0005] According to embodiments of this disclosure, a method is provided, comprising: acquiring a synchronization signal block including a Master Information Block (MIB) by a bandwidth-limited user equipment (UE) with bandwidth capability; identifying an Initial Control Resource Set (CORESET) based on an identifier bit set from the MIB; monitoring a portion of the Initial CORESET by the bandwidth-limited UE; and acquiring downlink control information (DCI).

[0006] In some embodiments: the initial CORESET occupies bandwidth greater than the bandwidth capacity of the bandwidth-limited UE; and the portion of the initial CORESET is a setting portion of the bandwidth occupied by the initial CORESET within the bandwidth capacity of the bandwidth-limited UE.

[0007] In some embodiments: the initial CORESET occupies bandwidth greater than the bandwidth capacity of the bandwidth-limited UE; a portion of the initial CORESET occupies bandwidth within the bandwidth capacity of the bandwidth-limited UE; and the portion of the initial CORESET is specified by reserved bits of the MIB.

[0008] In some embodiments, DCI includes a cyclic redundancy code (CRC) scrambled with bandwidth-limited SI-RNTI.

[0009] In some embodiments, the method further includes: acquiring bandwidth-limited system information block #1 (SIB1) via a scheduled physical downlink shared channel (PDSCH).

[0010] According to embodiments of this disclosure, a method is provided, comprising: acquiring a bandwidth-limited synchronization signal by a bandwidth-limited UE; acquiring an extended MIB (e-MIB) containing a first identifier bit set by the bandwidth-limited UE; identifying an initial control resource set (CORESET) based on the first identifier bit set; and monitoring the initial CORESET by the bandwidth-limited UE.

[0011] In some embodiments, the bandwidth-limited synchronization signal is a bandwidth-limited auxiliary synchronization signal.

[0012] In some embodiments, the step of monitoring the initial CORESET includes: the bandwidth-limited UE monitoring the initial CORESET for a DCI including a cyclic redundancy code (CRC) scrambled with a bandwidth-limited system information radio network temporary identifier (SI-RNTI).

[0013] In some embodiments, the method further includes: acquiring bandwidth-limited system information block #1 (SIB1) via a scheduled physical downlink shared channel (PDSCH).

[0014] In some embodiments, the bandwidth-limited synchronization signal is a bandwidth-limited master synchronization signal.

[0015] In some embodiments, the step of monitoring the initial CORESET includes: the bandwidth-limited UE monitoring the initial CORESET for a DCI including a cyclic redundancy code (CRC) scrambled with a bandwidth-limited system information radio network temporary identifier (SI-RNTI).

[0016] According to embodiments of this disclosure, a method is provided, comprising: acquiring a system information block #1 (SIB1) from a signal from a network by a bandwidth-limited user equipment (UE) with bandwidth capability, wherein SIB1 defines a conventional initial BWP; sending a first message to the network by the bandwidth-limited UE; receiving a second message from the network by the bandwidth-limited UE; sending a third message to the network by the bandwidth-limited UE; and receiving a fourth message from the network by the bandwidth-limited UE; wherein the step of sending the third message includes sending the third message in a first initial BWP different from the conventional initial BWP; or the step of receiving the fourth message includes receiving the fourth message in a second initial BWP different from the conventional initial BWP.

[0017] In some embodiments, the method further includes: receiving a first BWP identifier identifying the first initial BWP in a second message by a bandwidth-limited UE, wherein the step of sending a third message includes sending a third message in the first initial BWP.

[0018] In some embodiments, the step of receiving a fourth message includes: receiving a fourth message in a second initial BWP.

[0019] In some embodiments, the second initial BWP is different from the first initial BWP.

[0020] In some embodiments, the method further includes: receiving a second BWP identifier identifying the second initial BWP by a bandwidth-limited UE in a second message.

[0021] In some embodiments, the method further includes: receiving a second BWP identifier identifying the second initial BWP by a bandwidth-limited UE in SIB1 or an extended SIB1 (eSIB1).

[0022] In some embodiments, the method further includes: receiving, by a bandwidth-limited UE, a list of available initial BWPs including a first initial BWP in SIB1 or an extended SIB1 (eSIB1), wherein the step of sending a first message includes sending a first message in the first initial BWP.

[0023] In some embodiments, the method further includes: selecting a first initial BWP from a list of available initial BWPs by a bandwidth-limited UE.

[0024] In some embodiments, the method further includes: the bandwidth-limited UE notifying the network of its selection of a first initial BWP in a first message. Attached Figure Description

[0025] These and other features and advantages of this disclosure will be appreciated and understood by referring to the specification, claims and drawings, wherein:

[0026] Figure 1 This is a diagram illustrating the initial access process according to an embodiment of the present disclosure;

[0027] Figure 2 This is a diagram illustrating the sequence of bandwidth portions according to an embodiment of the present disclosure;

[0028] Figure 3A This is a table of bandwidth configurations according to embodiments of this disclosure;

[0029] Figure 3B It is a table of resource blocks and slot symbols according to embodiments of this disclosure;

[0030] Figure 4This is a diagram illustrating the initial access process according to an embodiment of the present disclosure;

[0031] Figure 5A This is a diagram illustrating the primary synchronization signal, secondary synchronization signal, and physical broadcast channel structure according to embodiments of the present disclosure;

[0032] Figure 5B This is a resource element allocation diagram according to an embodiment of the present disclosure;

[0033] Figure 5C This is a flowchart of a portion of the initial access process according to embodiments of the present disclosure;

[0034] Figure 6A This is a bandwidth portion diagram according to an embodiment of the present disclosure;

[0035] Figure 6B This is a diagram illustrating the initial access process according to an embodiment of the present disclosure;

[0036] Figure 6C This is a resource element allocation diagram according to an embodiment of the present disclosure;

[0037] Figure 6D This is a diagram illustrating the initial access process according to an embodiment of the present disclosure;

[0038] Figure 6E This is a resource element allocation diagram according to embodiments of the present disclosure; and

[0039] Figure 6F This is a flowchart of a portion of the initial access process according to an embodiment of the present disclosure. Detailed Implementation

[0040] The detailed description set forth below with reference to the accompanying drawings is intended as a description of exemplary embodiments of systems and methods for accommodating degraded user equipment in a mobile network according to the present disclosure, and is not intended to represent the only form in which the present disclosure may be constructed or utilized. This description illustrates features of the present disclosure in conjunction with the illustrated embodiments. However, it will be understood that the same or equivalent functions and structures may be implemented through different embodiments that are also intended to be included within the scope of this disclosure. As indicated elsewhere herein, the same element numbers are intended to indicate the same elements or features.

[0041] In Release 17 (Rel-17) of the 3rd Generation Partnership Project (3GPP), the standard for fifth-generation mobile networks (5G), one of the objectives of the Study on Reduced Capability NR Devices (SID) is to identify and study potential UE complexity reduction features, such as reduced user equipment (UE) bandwidth. With the introduction of bandwidth-limited (BL) UEs, there may be specification impacts on the UE initial access procedure (or "initial access processing") because BL UEs may be unable to perform traditional initial access procedures, where BL UEs have lower bandwidth capabilities than those required for traditional UEs.

[0042] As used herein, “traditional” refers to a system lacking specific provisions for accommodating bandwidth-limited UEs, or to elements of such a system (e.g., a traditional CORESET#0 or a traditional physical broadcast channel (PBCH)). As used herein, specific phrases (such as “user equipment” and “downlink control information”) are used as countable nouns, even if the nouns they contain (e.g., “equipment” and “information”) may be uncountable in general English. As used herein, a “bandwidth-limited UE” is a UE with bandwidth capabilities insufficient to meet the traditional bandwidth requirements on a UE. When applied to terms other than UE, the qualifier “bandwidth-limited” implies association with a bandwidth-limited UE. It may or may not mean that the qualifier itself has (e.g., occupies) limited bandwidth. For example, a “bandwidth-limited initial CORESET” may have limited bandwidth, but a “bandwidth-limited SI-RNTI” (or SI-BL-RNTI discussed below) does not need to occupy limited bandwidth.

[0043] As an example of this specification impact, in 3GPP Release 15 (Rel-15), the legacy initial control resource set (CORESET#0) can have a maximum bandwidth of 17 MHz (assuming a 15 kHz subcarrier spacing (SCS) and 96 physical resource blocks (PRBs) (each PRB comprising 12 subcarriers)). This 17 MHz maximum bandwidth can be greater than the maximum bandwidth for lower-layer bandwidth-limited UEs (e.g., 5 MHz or 10 MHz). In this case, the bandwidth-limited UE may not be able to obtain legacy system information block #1 (SIB1) information via legacy CORESET#0, and therefore may not be able to perform the initial access procedure. Furthermore, due to the lower bandwidth capability of the bandwidth-limited UE, the uplink initial bandwidth portion (BWP) of the bandwidth-limited UE may differ from the legacy uplink initial BWP. Therefore, providing mechanisms in the network and for the bandwidth-limited UE to enable uplink transmissions using a reduced uplink initial BWP may be advantageous.

[0044] Figure 1The diagram illustrates the traditional initial access procedure in NR. For example... Figure 1 As shown, the process may include the following steps (e.g., consisting of the following steps): At 110, the network base station (gNB) periodically transmits synchronization signal (SS) blocks (SSBs) carrying synchronization signals (including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) and a physical broadcast channel (PBCH) using beam scanning. An SS block contains one PSS symbol, one SSS symbol, and two PBCH symbols. A synchronization signal burst may carry one or more SS blocks. The combination of PSS and SSS helps identify approximately 1008 physical cell identifiers. Each UE performs beam measurement and determines the optimal beam during synchronization.

[0045] Subsequently, at 120, the gNB transmits 5G New Radio (NR) system information, and the UE receives and decodes the 5G New Radio (NR) system information, i.e., the Master Information Block (MIB) and System Information Block (SIB) on that beam. The minimum SI (System Information) is carried on the Physical Broadcast Channel. The remaining minimum System Information (RMSI) and the remainder of SIB1 are carried on the Physical Downlink Shared Channel (PDSCH). The parameter set used for RMSI is indicated in the PBCH payload. CORESET#0 is dedicated to RMSI scheduling. CORESET#0 is not limited to the PBCH bandwidth. There is an RMSI Physical Downlink Control Channel (PDCCH) monitoring window associated with the SS / PBCH block, where the SS / PBCH block recurs periodically. Other System Information (OSI) includes on-demand system information delivery. The OSI is carried on the PDSCH using the same parameter set as that used for RMSI. At 130, the UE uses the same beam and attempts random access by sending a Random Access Channel (RACH) preamble (i.e., message 1 or "message #1") on the configured RACH resources. The gNB responds with a Random Access Response RAR ("RA Response") message, which is message 2 or "message #2". Then, at 150, the UE sends message 3 or "message #3" (i.e., Radio Resource Control (RRC) Connection Request) on the Physical Uplink Shared Channel (PUSCH) (e.g., NR-PUSCH). Then, at 160, the gNB responds with message 4 or "message #4" (i.e., RRC Connection Establishment), which is a contention resolution message and completes the initial access process.

[0046] Figure 2This shows the different initial BWP types available for UEs in different RRC states. In some use cases, the idle mode BWP may be smaller than the connected mode BWP. Three types of BWPs are available: initial BWP, active BWP (UE-specific), and default BWP (UE-specific). The initial BWP is used to perform the initial access procedure. The initial BWP includes parameters such as RMSI (Minimum System Information Requested), CORESET#0 and RMSI frequency location, bandwidth, and SCS. The initial BWP can be between 24 and 96 PRBs with different settings and can be relaxed to a wider BWP after RMSI decoding. The active BWP is defined as UE-specific. The active BWP is the first BWP in which the UE begins data transmission after RRC configuration or reconfiguration. The first active BWP may differ from the default BWP.

[0047] Figure 3A The diagram illustrates the BWP configuration at different stages of the initial access process, considering both uplink and downlink BWPs. BWP configuration is divided into uplink and downlink parameters, as well as common and private parameters. Common parameters (in the uplink and downlink common BWPs) can be "cell-specific," and the network ensures necessary alignment with the corresponding parameters of other UEs. Common parameters for the initial BWP of the PCell are also provided via system information. For all other serving cells, common parameters are provided by the network via private signaling.

[0048] The CORESET#0 configuration is predefined in the set of tables, and the indexes of the tables to be used are included in the MIB message. Figure 3B The representation shows an example of the set of resource blocks and time slot symbols configured for CORESET#0 when the [SS / PBCH block, PDCCH]SCS is [15, 15] kHz (i.e., the SCS of the SS / PBCH block and PDCCH are 15 kHz and 15 kHz, respectively) for frequency bands with minimum channel bandwidths of 5 MHz and 10 MHz. The initial CORESET can be a CORESET for SIB1 / PDCCHType0. As used herein, "initial CORESET" means CORESET#0.

[0049] In some embodiments, accommodating bandwidth-limited UEs during initial access processing can be achieved through various methods identified herein as Embodiments 1, 2, and 3, where various options are possible for Embodiments 1 and 3. For ease of explanation, these embodiments are explained herein in the context of full-bandwidth UEs and bandwidth-limited UEs, where both full-bandwidth UEs and bandwidth-limited UEs perform initial access processing. In operation, numerous full-bandwidth UEs and numerous bandwidth-limited UEs can interact with the gNB at any time.

[0050] In one embodiment, referred to herein as Embodiment 1, such as Figure 4 As shown, the "RRC BL-SIB1" message is used by a bandwidth-constrained UE for initial access processing. (Reference) Figure 4 Both the legacy UE or "full bandwidth UE" and the bandwidth-limited UE acquire the Signal Synchronization Block (SSB) at 405 and decode the MIB. Both the legacy UE and the bandwidth-limited UE read the CORESET#0 configuration from the MIB.

[0051] A conventional UE monitors CORESET#0 for a DCI with a CRC scrambled by SI-RNTI, while a bandwidth-limited UE monitors CORESET#0 for a DCI with a CRC scrambled by SI-BL-RNTI. If CORESET#0 is configured with a bandwidth greater than the bandwidth capacity of the bandwidth-limited UE, the bandwidth-limited UE monitors a subset of CORESET#0 412. The subset of CORESET#0, or the rule used to determine the subset of CORESET#0, can be pre-configured for the bandwidth-limited UE. The bandwidth-limited UE then acquires BL-SIB1 at 435 via the scheduled Physical Downlink Shared Channel (PDSCH). The presence of BL-SIB1 in the RRC message indicates to the bandwidth-limited UE that the cell (e.g., the network node (gNB)) supports the bandwidth-limited UE. If the bandwidth-limited UE does not detect BL-SIB1, it stops initial access to that cell. Then, the bandwidth-limited UE can select BL-BWP#0 (within its bandwidth capacity) based on BL-SIB1 at 440, and receive and decode RRC signaling at 445 to configure a dedicated BWP for the specific bandwidth-limited UE.

[0052] For example, if CORESET#0 is configured with a bandwidth greater than the bandwidth capacity of the bandwidth-limited UE, the bandwidth-limited UE can determine which subset of CORESET#0 to monitor in one of the following two ways (referred to as Option 1 and Option 2).

[0053] In Option 1, when CORESET#0 is configured with a bandwidth greater than the bandwidth capacity of the bandwidth-limited UE, the DCI for the bandwidth-limited UE is always transmitted on a specific set of Control Channel Elements (CCEs) within CORESET#0. This specific set of Control Channel Elements (CCEs) within CORESET#0 may be referred to as the “initial CORESET setup portion”; as used herein, the “setup portion” is the portion defined before the start of initial access processing. The bandwidth-limited UE can be pre-configured to monitor the DCI for the bandwidth-limited UE using the specific set of CCEs within CORESET#0, or the bandwidth-limited UE can be pre-configured to monitor the DCI for the bandwidth-limited UE using rules for determining the specific set of CCEs within CORESET#0.

[0054] In Option 2, when CORESET#0 is configured with a bandwidth greater than the bandwidth capacity of the bandwidth-limited UE, additional reserved bits in the MIB (e.g., 1 bit or 2 bits) can be used to indicate which part of CORESET#0 the bandwidth-limited UE should monitor for DCI.

[0055] A full-bandwidth UE can receive and decode SIB1 via the scheduled Physical Downlink Shared Channel (PDSCH) based on DCI at 415, and obtain the initial BWP configuration (BWP#0) for both uplink and downlink from SIB1. Then, at 420, the full-bandwidth UE can select BWP#0 based on SIB1, and at 425, it can receive and decode RRC signaling to configure a dedicated BWP for a specific full-bandwidth UE.

[0056] Using Example 1 may (i) consume additional PDSCH resources for transmitting BL-SIB1, (ii) consume additional PDCCH resources for scheduling BL-SIB1, (iii) result in the duplication of multiple SIB1 Information Elements (IEs) in BL-SIB1, and (iv) consume reserved bits in the MIB if Option 2 is used. However, using Example 1 may have the advantage of supporting all CORESET#0 configurations of Rel-15 legacy UEs.

[0057] In another embodiment, referred to herein as Embodiment 2, SSB resource mapping may be used. For example, the presence of a bandwidth-limited secondary synchronization signal (BL-SSS) can be used to indicate support for a bandwidth-limited UE and to indicate the presence of an extended physical broadcast channel (ePBCH) for the bandwidth-limited UE. Figure 5A As shown, the primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH) structures can be reused. Figure 5BThis is a diagram showing the relative positions of (i) a traditional SS / PBCH block 510 (including PBCH, SSS, PSS) and (ii) an additional block 515 (including BL-SSS and ePBCH) that can be added to support bandwidth-limited UEs.

[0058] The initial access process according to Embodiment 2 may include the following steps. First, both the conventional UE and the bandwidth-limited UE can acquire the PSS. Then, the bandwidth-limited UE can acquire the BL-SSS, wherein the presence of the BL-SSS indicates support for the bandwidth-limited UE. Instead of the BL-SSS (or other than the BL-SSS), the bandwidth-limited PSS (BL-PSS) can be used for the same purpose. Then, the bandwidth-limited UE acquires the eMIB from the ePBCH and reads the BL-CORESET#0 configuration from the eMIB. Then, the bandwidth-limited UE monitors CORESET#0 for DCI with a CRC scrambled by SI-BL-RNTI. Then, the bandwidth-limited UE acquires BL-SIB1 via the scheduled PDSCH.

[0059] The use of Embodiment 2 may (i) consume additional PDCCH and PDSCH resources for scheduling and transmitting BL-SIB1, (ii) consume additional resources for ePBCH and BL-SSS, and (iii) result in the duplication of multiple SIB1 Information Elements (IEs) in BL-SIB1. However, the use of Embodiment 2 may have the advantages of allowing all CORESET#0 configurations and providing complete flexibility in configuring BL-CORESET#0. Figure 5C This is a flowchart of a portion of the initial access process according to Embodiment 2. Figure 5C In the flowchart, the bandwidth-limited UE performs the following steps: at 535, acquires a bandwidth-limited synchronization signal; at 540, acquires an extended MIB (e-MIB) containing a first identifier bit set; at 545, identifies an initial control resource set (CORESET) based on the first identifier bit set; and at 550, configures the bandwidth-limited UE using the initial CORESET.

[0060] In another embodiment, referred to herein as Embodiment 3, an Initial Bandwidth Part (BWP) handover is used in the initial access process. Reduced-capability UEs may have a reduced number of receive (RX) antennas, resulting in a greater demand for resources used for PDCCH and PDSCH. To compensate for the potential coverage reduction caused by the reduced number of receive antennas, more downlink resources can be used to serve the same number of reduced-capability UEs in a given coverage area. Supporting a similar number of UEs for enhanced mobile broadband (eMBB) can be challenging unless the initial BWP configured for a reduced-capability UE is allowed to be greater than the RF bandwidth of the reduced-capability UE. In Rel-15, all downlink common signals and channels prior to the establishment of a Radio Resource Control (RRC) connection (such as paging and messages for the Random Access Channel (RACH) in addition to all scheduled DCIs) are transmitted in the initial BWP. Therefore, if only the initial BWP is used for all reduced-capability UEs, congestion may occur in the initial access of reduced-capability UEs for both downlink and uplink.

[0061] Another issue might be that, for message 1 transmission, when the 8 RACH opportunities (ROs) are frequency-division multiplexed with a 30kHz subcarrier spacing (SCS), the total bandwidth used for initial access exceeds 20MHz. If the reduced-capacity UE supports a maximum bandwidth of 20MHz (i.e., a maximum uplink initial BWP size of 20MHz), then ROs outside the uplink initial BWP cannot be used, and therefore the UE may not be able to transmit the Physical Random Access Channel (PRACH) corresponding to the optimal SSB.

[0062] The two issues mentioned above can be mitigated using the following two options (referred to as Option 1 and Option 2). In each of these options, the decommissioned UE can operate using a different uplink initial BWP and downlink initial BWP than the traditional uplink initial BWP and traditional downlink initial BWP (where each of the "traditional initial BWPs" is an initial BWP (e.g., an uplink initial BWP or a downlink initial BWP) identified by the network in SIB1 as to be used by a traditional UE). In Option 1, the DCI-based initial BWP handover on message 2 of the initial access processing is used to transfer both downlink signaling load and uplink signaling load across a set of different downlink initial BWPs or uplink initial BWPs used for the decommissioned UE, instead of using only one uplink initial BWP or downlink initial BWP configured in SIB1. The gNB configures a specific new uplink initial BWP and downlink initial BWP for each decommissioned UE using the same RO and preamble. A new set of Returning Objects (ROs) can be defined for UEs with reduced bandwidth capabilities, as well as a new mapping between the SSB index for beam pairing and the new ROs. The new ROs can not overlap, partially overlap, or completely overlap with the traditional ROs.

[0063] For the downlink initial BWP of a UE with reduced capabilities, such as Figure 6A As shown, the network can transfer UEs with different reduced capabilities to different initial BWPs. Figure 6A The network demonstrates that it can transfer a degraded UE to one or more different uplink initial BWPs (each uplink initial BWP is different from the traditional uplink initial BWP) and one or more different downlink initial BWPs (each downlink initial BWP is different from the traditional downlink initial BWP). Specifically, upon receiving message 1, the network determines that each degraded UE performs a downlink initial BWP handover via the DCI in message 2 (e.g., Figure 6B As shown in the diagram, each UE with reduced capability within the same RO is assigned a specific initial BWP. For the uplink initial BWP, the network supporting the reduced capability may have an additional mapping between the SSB index of the bandwidth-constrained UE with reduced capability and the new RO. In SIB1, the UE with reduced capability is notified of (i) this new mapping, and (ii) the new RO. For example, as shown in the diagram... Figure 6CAs shown, the frequency or time resources (or both) of the new RO may not overlap, partially overlap, or completely overlap with the frequency or time resources (or both) of the traditional RO. If the new RO overlaps with the traditional RO, the network may determine whether to apply the traditional SSB index mapping rule or the new mapping rule based on the specific preamble used by the de-capable UE in Message 1. When Message 1 is transmitted using the new RO and the new mapping by a de-capable UE, the network knows (i) the set of de-capable UEs in the cell and (ii) beam pairing information. The network then selects and configures a specific uplink initial BWP for each de-capable UE, such that de-capable UEs are distributed across different new uplink initial BWPs for Message 3 transmission. For example, de-capable UEs may be randomly distributed across different uplink initial BWPs. As another example, de-capable UEs may be distributed across different uplink initial BWPs, where the probability is inversely proportional to the number of UEs in that uplink initial BWP. The network may also (in Message 2) select and configure a specific downlink initial BWP for each de-capable UE. For a given UE with reduced capability, the uplink initial BWP and downlink initial BWP may each be different from the initial BWP used to transmit SSB, and the uplink initial BWP and downlink initial BWP may be different from each other.

[0064] When a degraded UE is in the RRC_connected state, a downlink initial BWP handover for the degraded UE can also occur. For example, the current downlink initial BWP of the degraded UE may not contain an SSB. When the degraded UE performs Radio Resource Management (RRM) measurements or performs initial access, the degraded UE can perform a downlink initial BWP handover to a downlink initial BWP that includes an SSB. As another example, a degraded UE can perform initial BWP hopping across different downlink initial BWPs throughout the entire carrier bandwidth to gain frequency diversity gain.

[0065] In option 2 (in) Figure 6D As shown in the diagram, the network can allocate a set of possible initial BWPs for de-capacitated UEs in SIB1 or in a separate extended SIB1 (eSIB1) sent by the network. Each de-capacitated UE can then autonomously select an initial BWP for PRACH to balance the load across different initial BWPs (instead of all de-capacitated UEs sharing a single initial BWP). Each de-capacitated UE can then notify the network of its initial BWP selection in message 1. As in option 1, the network can (in message 2) select and configure a specific downlink initial BWP for each de-capacitated UE.

[0066] The network pre-configures a set of uplink initial BWPs and configures a new RO in each configured uplink initial BWP. The network also configures a set of downlink initial BWPs so that de-capable UEs do not need to share a single downlink initial BWP. The network also pre-configures new SSB index-to-RO mapping rules in the new ROs for de-capable UEs; that is, the network pre-configures a new mapping between SSB indices in each uplink initial BWP and the new RO. The network notifies the de-capable UEs of all the above configurations in an SIB1 message. Then, each de-capable UE autonomously selects an uplink initial BWP and a downlink initial BWP for PRACH to balance the load across different initial BWPs (instead of all de-capable UEs sharing a single initial BWP). Each de-capable UE may notify the network of its selection of the downlink initial BWP and uplink initial BWP in message 1, for example, via a specific preamble or a combination of a specific preamble and a new RO. For example, if the new RO overlaps with the traditional RO, the selected uplink initial BWP and downlink initial BWP are indicated by a specific preamble for the UE used to reduce capabilities, or by a combination of a specific preamble and the new RO.

[0067] In the case of 2-step RACH, in order to support UEs with reduced capabilities, such as Figure 6E As shown, the network predefines separate SSB-to-RO and SSB-to-PUSCH timing (PO) mappings, which are customized to support the limited bandwidth of UEs with reduced capabilities. Specifically, new mapping rules between SSBs, ROs, and POs, as well as between new ROs and new POs, are defined according to the initial BWP for UEs with reduced capabilities and are sent to the UEs with reduced capabilities in SIB1. The new PO for UEs with reduced capabilities may partially or completely overlap with the traditional RO. UEs with reduced capabilities can be configured using the set of downlink initial BWPs and uplink initial BWPs in SIB1, and each UE can autonomously select one downlink initial BWP and one uplink initial BWP and notify the network.

[0068] Figure 6F This is a flowchart of a portion of the initial access process according to Embodiment 3. Figure 6F In the flowchart, the bandwidth-limited UE performs the following steps: at 635, it acquires a synchronization signal block (SSB) in a first initial bandwidth portion (BWP) from a signal from the network; at 640, it sends a first message to the network; at 645, it receives a second message from the network; and at 650, it sends a third message to the network in a second initial BWP that is different from the first initial BWP.

[0069] In some embodiments, the methods described herein may be performed by the processing circuitry of the UE or by the processing circuitry of the network, or both. For example, the processing circuitry of the UE may send messages 1 and 3 of the initial access processing to the network (via a wireless device in the UE). The term "processing circuitry" is used herein to refer to any combination of hardware, firmware, and software employed to process data or digital signals. Processing circuitry hardware may include, for example, application-specific integrated circuits (ASICs), general-purpose or special-purpose central processing units (CPUs), digital signal processors (DSPs), graphics processing units (GPUs), and programmable logic devices such as field-programmable gate arrays (FPGAs). In processing circuitry, as used herein, each function may be performed by hardware configured (i.e., hardwired) to perform that function, or by more general-purpose hardware (such as a CPU) configured to execute instructions stored in a non-transitory storage medium. Processing circuitry may be fabricated on a single printed circuit board (PCB) or distributed across several interconnected PCBs. Processing circuitry may include other processing circuitry; for example, processing circuitry may include two processing circuits, an FPGA and a CPU, interconnected on a PCB.

[0070] As used herein, a “part” of something means “at least some” of that thing, and therefore can mean less than all of that thing or mean all of that thing. Thus, as a special case, a “part” of something includes the whole thing, i.e., the whole thing is an example of a part of something. As used herein, when the second number is “within Y%” of the first number, it means that the second number is at least (1-Y / 100) times the first number, and at most (1+Y / 100) times the first number. As used herein, the term “or” should be interpreted as “and / or”, such that, for example, “A or B” means any one of “A” or “B” or “A and B”.

[0071] As used herein, when a method (e.g., regulation) or a first quantity (e.g., a first variable) is referred to as “based on” a second quantity (e.g., a second variable), it means that the second quantity is an input to the method or affects the first quantity. For example, the second quantity may be an input to a function that computes the first quantity (e.g., a unique input or one of several inputs), or the first quantity may be equal to the second quantity, or the first quantity may be the same as the second quantity (e.g., stored in one or more locations in memory that are the same as the second quantity).

[0072] It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or portion from another. Therefore, without departing from the spirit and scope of the inventive concept, the first element, component, region, layer, or portion discussed herein may be referred to as the second element, component, region, layer, or portion.

[0073] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept. As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than as terms of degree, and are intended to take into account the inherent biases of measurements or calculations that will be recognized by one of ordinary skill in the art.

[0074] As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will also be understood that, when used in this specification, the term “comprising” specifies the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups thereof, or the addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of…” modify the entire list of elements when following a list of elements, without modifying any individual element of the entire list. Furthermore, the use of “may” when describing embodiments of the inventive concept refers to “one or more embodiments of this disclosure.” Additionally, the term “exemplary” is intended to refer to an example or illustration. As used herein, the term “use” may be considered synonymous with the term “utilize.”

[0075] Any numerical range described herein is intended to include all subranges containing the same numerical precision within the range. For example, the range “1.0 to 10.0” or “between 1.0 and 10.0” is intended to include all subranges between (and including) the minimum value 1.0 and the maximum value 10.0, i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein.

[0076] While exemplary embodiments of systems and methods for accommodating degraded user equipment in a mobile network have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Therefore, it will be understood that systems and methods for accommodating degraded user equipment in a mobile network, constructed in accordance with the principles of this disclosure, can be implemented in ways other than those specifically described herein. The invention is also defined in the appended claims and their equivalents.

Claims

1. A method for accommodating a degraded user equipment (UE) in a mobile network, comprising: A bandwidth-limited UE with bandwidth capability acquires a synchronization signal block, including the main information block (MIB). The initial control resource set CORESET is identified based on the identifier bit set from the MIB; A portion of the initial CORESET is monitored by the bandwidth-constrained UE; and Obtain downlink control information (DCI).

2. The method of claim 1, wherein: The initial CORESET occupies more bandwidth than the bandwidth-limited UE can handle; and The aforementioned part of the initial CORESET is the bandwidth setting part within the bandwidth capacity of the bandwidth-limited UE of the initial CORESET.

3. The method of claim 1, wherein: The initial CORESET occupies more bandwidth than the bandwidth-limited UE can handle; The initial portion of the CORESET occupies bandwidth limited to the UE's bandwidth capacity; and The aforementioned portion of the initial CORESET is specified by reserved bits in the MIB.

4. The method of claim 1, wherein, The DCI includes a cyclic redundancy code (CRC) scrambled with the bandwidth-limited System Information Radio Network Temporary Identifier (SI-RNTI).

5. The method of claim 4, further comprising: The bandwidth-limited system information block #1 SIB1 is obtained through the scheduled physical downlink shared channel PDSCH.

6. A method for accommodating a degraded user equipment (UE) in a mobile network, comprising: Bandwidth-limited UE obtains bandwidth-limited synchronization signal; The bandwidth-constrained UE obtains an extended MIB containing the first identifier bit set; The initial control resource set (CORESET) is identified based on the first identifier bit set. and Initial CORESET is monitored by a bandwidth-limited UE.

7. The method of claim 6, wherein, The bandwidth-limited synchronization signal is a bandwidth-limited auxiliary synchronization signal.

8. The method of claim 7, further comprising: The bandwidth-limited system information block #1 SIB1 is obtained through the scheduled physical downlink shared channel PDSCH.

9. The method of claim 6, wherein, The bandwidth-limited synchronization signal is the bandwidth-limited master synchronization signal.

10. The method of claim 7 or 9, wherein, The steps for monitoring the initial CORESET include: monitoring the initial CORESET by a bandwidth-limited UE against a DCI including a cyclic redundancy code (CRC) scrambled with a bandwidth-limited system information radio network temporary identifier (SI-RNTI).

11. A method for accommodating a degraded user equipment (UE) in a mobile network, comprising: A bandwidth-limited UE with bandwidth capability acquires system information block #1 SIB1 from signals from the network, where SIB1 defines the traditional initial bandwidth portion (BWP). The bandwidth-limited UE sends the first message to the network; The second message is received from the network by a bandwidth-limited UE; A third message is sent from a bandwidth-limited UE to the network; and The fourth message is received from the network by a bandwidth-limited UE; in: The steps for sending a third message include: sending a third message in a first initial BWP that is different from the traditional initial BWP; or The steps for receiving the fourth message include: receiving the fourth message in a second initial BWP that is different from the conventional initial BWP.

12. The method of claim 11, further comprising: The bandwidth-limited UE receives the first BWP identifier, which identifies the first initial BWP, in the second message. The step of sending the third message includes: sending the third message in the first initial BWP.

13. The method of claim 11, wherein, The steps for receiving the fourth message include: receiving the fourth message in the second initial BWP.

14. The method of claim 13, wherein, The second initial BWP is different from the first initial BWP.

15. The method of claim 13, further comprising: The second BWP identifier, which identifies the second initial BWP, is received by the bandwidth-limited UE in the second message.

16. The method of claim 13, further comprising: The second BWP identifier, which identifies the second initial BWP, is received by the bandwidth-limited UE in SIB1 or an extended SIB1.

17. The method of claim 11, further comprising: The bandwidth-limited UE receives a list of available initial BWPs, including the first initial BWP, in SIB1 or extended SIB1. The step of sending the first message includes: sending the first message in the first initial BWP.

18. The method of claim 17, further comprising: The bandwidth-limited UE selects the first initial BWP from the list of available initial BWPs.

19. The method of claim 18, further comprising: In the first message, the bandwidth-limited UE notifies the network of its selection of the first initial BWP.

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