Method for enhanced scheduling of network resources for reduced capability user equipment

Abstract

The present invention relates to a method of operating a base station as part of a cellular network, the base station serving a plurality of user equipments, the base station operating in at least one supported frequency band in the uplink direction and in one supported frequency band in the downlink direction, wherein the plurality of user equipments includes at least one user equipment identified as a reduced capability user equipment, wherein the base station is configured to ascertain capability information from the reduced capability user equipment indicating a capable uplink frequency bandwidth and a capable downlink frequency bandwidth, wherein, for scheduling at least one reduced capability user equipment, the method comprises the following steps for the base station: - taking into account the received capability information, transmitting at least one first downlink signal for the user equipment, the first downlink signal indicating an assignment to a scheduled uplink frequency band, - scheduling information in the scheduled downlink frequency band for transmission synchronously with a predetermined nominal interval with respect to the scheduled uplink frequency band based on the scheduled downlink frequency band and a center of the scheduled uplink frequency band.

Description

Technical Field

[0001] The present invention relates to a method for operating a base station, a base station using the method, a method for a user equipment, and a user equipment using the method. Background Art

[0002] In the field of wireless communications, it has been known to date that user equipment operates on the full bandwidth provided by the base stations of the cellular network in which they operate, or only on a reduced bandwidth. For LTE devices supporting CAT-1 or higher, the full bandwidth is covered, while in Cat-M or NB-IoT, only a subset, such as 1.4 MHz, is processed. These are so-called reduced bandwidth (BR) devices.

[0003] This design has the disadvantage that devices with reduced bandwidth cannot communicate in full duplex, meaning they are scheduled for downlink operation or for uplink operation at the same time.

[0004] However, with the development of the New Radio (NR) standard, and therefore the 5G standard, there are plans to eliminate this limitation and also allow user equipment that is not capable of operating at the full bandwidth of a base station (in 5G, the base station is called a gNodeB) to operate in full-duplex mode. These are so-called NR Light or NR-REDCAP (Reduced Capability) devices, hereinafter generally referred to as reduced-capability user equipment.

[0005] In order to do so, some modifications need to be made to the known interoperation between user equipment and base station, eg compared to existing PDCCH monitoring rules.

[0006] One of the issues to be addressed to meet this new requirement is scheduling over a reserved frequency range in both the uplink and downlink. With full-bandwidth devices, uplink and downlink transmissions are processed across the entire bandwidth, and the scheduled PRBs for the user equipment are then further processed, while the others are discarded. At least for frequency-domain (FDD) deployments, the uplink and downlink frequency ranges have a known nominal spacing defined in the standards. Thus, the uplink frequency band is defined for the user equipment, for example, by the start of the frequency band used for the downlink and this nominal spacing.

[0007] This method is not suitable for devices with reduced bandwidth. Furthermore, it is not foreseen to reserve certain frequency areas for such devices, but rather to apply a scheduling distributed over the entire bandwidth provided by the gNodeB.

[0008] Therefore, a solution is needed on how to schedule decodable frequency bands in uplink and downlink without significant signaling overhead.

[0009] It is therefore an object of the present invention to propose a solution for improved scheduling of user equipments with reduced bandwidth.

[0010] Therefore, there is a need in the art for further alternative and advantageous solutions. Summary of the Invention

[0011] To this end, according to a first aspect of the present invention, a method is provided for a base station according to claim 1. According to a second aspect of the present invention, a base station according to claim 7 is further provided. In a third aspect of the present invention, a method is provided for a user equipment according to claim 12. In a fourth aspect of the present invention, a user equipment according to claim 16 using said method is further provided.

[0012] In a first aspect of the present invention, a method of operating a base station as part of a cellular network is proposed, the base station serving a plurality of user equipments, the base station operating in at least one supported frequency band in an uplink direction and in one supported frequency band in a downlink direction, wherein the plurality of user equipments comprises at least one user equipment identified as a reduced capability user equipment, wherein the base station is configured to ascertain capability information indicating a capable uplink frequency bandwidth and a capable downlink frequency bandwidth from the reduced capability user equipment, wherein, in order to schedule the at least one reduced capability user equipment, the method comprises the following steps for the base station:

[0013] - transmitting at least one first downlink signal for the user equipment taking into account the received capability information, the first downlink signal indicating an assignment of a scheduled uplink frequency band,

[0014] - scheduling information in the scheduled downlink frequency band for transmission synchronously with a predetermined nominal interval to the scheduled uplink frequency band based on centers of the scheduled uplink frequency band and the scheduled downlink frequency band.

[0015] The method of the present invention relates to a base station of a cellular network, in particular to a base station of a cellular network implementing 3G, 4G or higher wireless technology standards. The base station can serve reduced-capability user equipment, which should register and camp on the base station.

[0016] A reduced capability user equipment is defined by the fact that it cannot handle the full frequency band deployed by the base station, in particular due to limited hardware resources. In practice, it is preferred to address only the frequency bandwidth that it is capable of using, both in uplink (UL) and downlink (DL) directions.

[0017] In this set, the following terms are distinguished:

[0018] The supported frequency band (UL and DL) describes what a base station can offer. It's essentially the maximum range of uplink or downlink communications possible. It's essentially a specific range, specifically defined by a starting frequency and length (i.e., bandwidth).

[0019] The supported frequency bands are in different ranges for uplink and downlink for FDD deployments, whereas they are the same range in TDD deployments.

[0020] The capable frequency bandwidth (in UL and DL) describes the bandwidth that the user equipment can handle. Since this defines a reduced bandwidth device, the capable frequency bandwidth is smaller than the bandwidth of the supported frequency band of at least one base station with which the user equipment wishes to operate.

[0021] In contrast, the scheduled frequency bands (in UL and DL) define what and where in the supported frequency bands the user equipment's capable frequency bandwidth should be used for UL / DL transmissions with the base station.

[0022] In order to serve the reduced capability user equipments, the base station needs to perform scheduling.

[0023] In addition, for reduced-capability user equipment, duplex operation is expected to be operable, which means scheduling, transmitting, and processing uplink and downlink data exchanges in parallel. This is consistent with the deployment of NR-Light (NR-REDCAP) in the technical standard definition of NR (New Radio) (5G).

[0024] Preferably, due to the fact that data exchange sessions can last longer with low payload exchanges, the base station will not restrict itself to defining a specific area of ​​the fully supported frequency band for this user equipment. This would prevent the base station from serving other user equipment, especially fully capable user equipment.

[0025] This is where the method of the present invention comes in. According to the method of the present invention, the solution is performed by the following method steps.

[0026] As a prerequisite, the base station first determines capability information from the corresponding user equipment with reduced capabilities. This is performed in particular during registration or in conjunction with a request to open a corresponding context for a data exchange session.

[0027] By using the capability information, the base station obtains at least an indication of the uplink frequency bandwidth and the downlink frequency bandwidth that it can use, which is usually indicated by a value in MHz.

[0028] Alternatively or additionally, multiple subcarriers, particularly in the case of variable subcarrier spacing, are provided as the indication. Regardless of the spacing applied (if uniform), the number of supported subcarriers is a measure of the parallel processing capability in the user equipment, i.e., the number of subcarriers that can be processed in parallel. For a given throughput, the larger the spacing, the smaller the symbol / frame duration, and the faster the processing time / speed in the user equipment needs to be.

[0029] The indication of capability information may only include the uplink or downlink frequency bandwidth that can be used, which is directly or indirectly applied to the bandwidth in other directions. Therefore, it may be sufficient to transmit a value for indicating the uplink frequency bandwidth that can be used and the downlink frequency bandwidth that can be used. Preferably, the user equipment provides other information related to general user equipment capabilities together with the capability information.

[0030] This exchange is performed during the registration process of the user equipment at the base station. In particular, during said registration process, the request is submitted in response to a capability request of the base station. However, the method of the present invention also includes an initial submission by the user equipment.

[0031] Preferably, at the timing of the data exchange session, the base station transmits at least one first downlink signal to the user equipment, wherein the downlink frequency band for scheduling the next upcoming data exchange session is indicated.

[0032] The scheduled downlink frequency band is determined by taking into account capability information received earlier from the user equipment. In particular, the scheduled downlink frequency band is determined by taking into account the downlink frequency bandwidth that the reduced-capability user equipment is capable of using.

[0033] This information at least means notifying the frequency band that needs to be monitored by the user equipment, as physical resource blocks (PRBs) or symbols designated for the user equipment may be transmitted.

[0034] Generally, it is known that user equipment can decode and process the entire frequency band deployed by the base station. Therefore, anywhere in the PRB or Master Information Block (MIB) can be transmitted control information indicating the location where signaling data, such as payload data, specific to the user equipment is transmitted.

[0035] For user equipments with reduced capabilities this approach is no longer possible.Thus, with the first downlink signal the user equipment is informed which frequency band window it has to monitor for the incoming data exchange session.

[0036] However, the first downlink signal needs to be transmitted in a frequency range monitored by the user equipment.

[0037] According to a preferred embodiment, it is proposed to perform the transmission of the first downlink signal as follows:

[0038] - based on a predetermined proximity around the master information block, or

[0039] - as announced by the base station in broadcast signaling, or

[0040] - in a portion of the supported downlink frequency band identified by a hopping sequence taking into account user equipment specific elements, or

[0041] - In a portion of the supported downlink frequency band identified by a frequency hopping sequence taking into account frame timing relations.

[0042] With this embodiment, it is ensured that the reduced capability user equipment is able to receive the first downlink signal.

[0043] In a preferred first option, the first downlink signal is transmitted within a predetermined range around a master information block, respectively a broadcast channel BCH.In any case, the user equipment is expected to read the BCH and / or MIB and therefore tune itself to receive this range.

[0044] Therefore, this range is preferably also used for submitting the first downlink signal.

[0045] Alternatively or additionally, the base station sends in broadcast signaling, in particular as part of system information, that the first downlink signal is transmitted in a downlink frequency band supported by the base station.

[0046] This option also takes into account that the user equipment is tuned to the MIB and will therefore notice the first downlink signal in any case.

[0047] This is advantageous because the area around the MIB is typically quite well populated. Furthermore, this allows for a smaller downlink frequency band to be used in a suitable and sufficiently large area. If the user equipment is only capable of extracting the size of the MIB, i.e., the minimum size that a reduced-capability user equipment needs to be able to receive and decode, there is no space for the first downlink signal.

[0048] As a third option, it is proposed to submit the first downlink signal in a part of the supported downlink frequency band identified by a frequency hopping sequence taking into account user equipment specific elements.

[0049] This detailed method defines a frequency hopping sequence that takes into account user equipment-specific elements such as an ID (e.g., IMEI) or any other element that determines the frequency hopping sequence. Both the user equipment and the base station can derive the frequency hopping sequence from the user equipment-specific elements in a timely manner, and therefore both have knowledge of which portion of the base station's supported downlink frequency band the user equipment needs to monitor for the first downlink signal.

[0050] As a variation of the third option, the fourth option also defines a frequency hopping sequence. However, this is identified by taking into account the frame timing relationship, i.e., the frame number or the connection timing.

[0051] The frame timing relationship may relate to the SFN (System Frame Number), which means the SFN itself or used in a calculation like modulo with a predefined value.

[0052] The predefined value may be the frequency bandwidth supported by the base station divided by the frequency bandwidth capable of being used by the user equipment, rounded to a smaller integer.

[0053] In addition, the SFN mode may use the IMEI of the user equipment or a derived value thereof.

[0054] This variant can also take into account the CFN, which is the Connection Frame Number. This describes when the connection was established, starts at 0, and counts system frames thereafter.

[0055] A third and / or fourth option consists in considering said resulting number, for example, as the number of positions for the scheduled frequency band.Thus, a specific order of frequency hopping can be determined, which specific order is an individual frequency hopping sequence for said user equipment.

[0056] As part of the present invention, other options or combinations of the mentioned options are also possible to ensure that the user equipment receives the first downlink signal.

[0057] The first downlink signal indicates an assignment of a scheduled uplink frequency band, in short, an uplink assignment.

[0058] Preferably, such indication is sent together with the first downlink signal, or at least sent within the frequency band of the first downlink signal.

[0059] Alternatively or additionally, such indication is performed indirectly using the first downlink signal.

[0060] According to the method, the step of transmitting at least one first downlink signal comprises indicating a scheduled downlink frequency band, and transmitting the assignment of the scheduled uplink frequency band within the scheduled downlink frequency band.

[0061] With this method, a first downlink signal indicates a scheduled downlink frequency band. Within the scheduled uplink frequency band, the user equipment monitors another transmission dedicated to the user equipment. Such transmission may include downlink payload data for the user equipment.

[0062] A signal including the uplink assignment is submitted to a scheduled uplink frequency band within the scheduled downlink frequency band.

[0063] With this uplink assignment, the user equipment can derive in which uplink frequency band it can perform uplink transmissions.

[0064] However, due to the fact that duplex data transmission is foreseen, additional downlink data transmission may be performed simultaneously with the uplink transmission, and therefore the user equipment needs to monitor the additional downlink data transmission. In practice, there is no guarantee that this will remain within the scheduled downlink frequency band as indicated by the first downlink signal. The base station may schedule this in a completely different area of ​​the downlink frequency band supported by the user equipment.

[0065] Therefore, scheduling is performed in such a way that, according to the scheduled uplink frequency band, the synchronously scheduled downlink frequency band is available in a predetermined nominal interval.

[0066] The predetermined nominal interval is preferably a constant value known to the user equipment and the base station, and is in particular predefined in a standard definition.

[0067] The predetermined nominal spacing is applied from the center of the scheduled uplink frequency band and thus results in the center of the resulting scheduled downlink frequency band.

[0068] This is advantageous since the scheduled uplink and downlink frequency bands will most likely differ in size.Thus, the nominal spacing applied to the centre of the respective frequency ranges ensures that the frequency bands will be well distributed.

[0069] In particular, the so-called duplex gap defined as a fixed value in 3GPP TS 36.101 can be applied here. This is particularly applicable to frequency division duplex operation.

[0070] According to a preferred embodiment, in case of operation of the base station in time domain duplexing (TDD), the nominal spacing is zero.

[0071] This means that for TDD operation, the scheduled uplink frequency band and the scheduled downlink frequency band are the same, with uplink and downlink transmissions separated by time rather than frequency.

[0072] By utilizing this aspect of the method of the present invention, it is ensured that parallel uplink and downlink scheduling can be continuously applied without additional signaling of the parallel uplink and downlink scheduling, and the reduced capability user equipment can safely monitor the scheduled downlink data.

[0073] In a further preferred embodiment, a step of determining whether the scheduled downlink frequency band protrudes from the supported downlink frequency band is proposed and, if so, modifying the scheduling by shifting the scheduled downlink frequency band to the edge of the supported downlink frequency band.

[0074] This embodiment covers the situation that may arise when the scheduled downlink frequency band is larger in size than the scheduled uplink frequency band.

[0075] In this case, deployment of a scheduled uplink band close to the edge of the fully supported uplink band of a base station will result in a situation where parallel downlink bands (deployed at predetermined nominal intervals) will protrude from the edge of the supported downlink band.

[0076] This is a first disadvantage, as it will reduce the total available size of the scheduled downlink frequency band. Second, it should be ensured that the entire supported uplink frequency band of the base station should be available for scheduling reduced-capability user equipment. Third, it is advantageous to deploy at the edge of the supported downlink frequency band, as this ensures that the scheduling region does not overlap with the MIB.

[0077] In this embodiment, this situation is covered by first detecting it. This is easily done by calculating the scheduled downlink frequency band from the scheduled uplink frequency band, in particular by considering the user equipment's capable frequency bandwidth as the maximum (and default) bandwidth to be monitored.

[0078] If such a situation is detected, the downlink scheduling is modified to address the situation by shifting the scheduled downlink frequency band to the edge of the base station's supported downlink frequency band for downlink transmissions.

[0079] In this sense, the predetermined nominal interval no longer applies, but rather for a safe and robust operation mode for both user equipment and base station it is ensured that the entire scheduled frequency band can be used.

[0080] According to another preferred embodiment, it is proposed that after performing uplink transmission taking into account the scheduled uplink frequency band, a second scheduled downlink frequency band is determined taking into account at least one of the following:

[0081] - said predetermined proximity around a Master Information Block (MIB),

[0082] - the broadcast signaling,

[0083] - said portion of the supported downlink frequency band identified by said frequency hopping sequence,

[0084] - The previously used scheduled downlink frequency band.

[0085] The present embodiment relates to a case when a user equipment performing uplink data transmission completes the uplink data transmission and thus does not request an additional scheduled uplink frequency band.

[0086] Therefore, there may be no uplink assignments where, with the nominal spacing, the scheduled downlink frequency band can be derived.

[0087] It would be disadvantageous to provide unsolicited uplink assignments, only to derive the scheduled downlink frequency band from them. This would waste the base station's resources.

[0088] Therefore, it is proposed to derive the scheduled downlink frequency band from other metrics for further monitoring of downlink transmissions to user equipments.

[0089] Firstly, the same options as for the first downlink signal apply here.

[0090] Instead, the previously scheduled downlink frequency band is maintained. While assigning a fixed region to a user equipment for a longer duration is disadvantageous, maintaining it is advantageous to ensure, for example, that the HARQ process completes. Since the HARQ process requires potentially repeated data transmissions, it is advantageous to ensure that this is performed on the same scheduled downlink frequency band and can therefore be easily and securely received by the user equipment.

[0091] After the HARQ process is completed (either successfully terminated or after a timeout failure), it is beneficial to ensure that downlink scheduling for the user equipment can also occur in another frequency band.

[0092] Therefore, combinations of the mentioned options are also proposed as part of this embodiment.

[0093] According to a second aspect of the present invention, a base station as part of a cellular network is provided, the base station being configured to serve a plurality of user equipments, the base station operating in at least one supported frequency band in an uplink direction and in one supported frequency band in a downlink direction, wherein the plurality of user equipments comprises at least one user equipment identified as a reduced capability user equipment, wherein the base station is configured to ascertain capability information indicating a capable uplink frequency bandwidth and a capable downlink frequency bandwidth from the reduced capability user equipment, wherein, in order to schedule the at least one reduced capability user equipment, the base station is configured to:

[0094] - transmitting at least one first downlink signal for said user equipment taking into account the received capability information indicating the assignment of the scheduled uplink frequency band,

[0095] - Based on the centers of the scheduled uplink frequency band and the scheduled downlink frequency band, scheduling information in the scheduled downlink frequency band for synchronous transmission to the scheduled uplink frequency band at predetermined nominal intervals.

[0096] This aspect of the invention relates to a base station for serving a plurality of user equipments.

[0097] A base station is part of a cellular network, which preferably includes multiple base stations. This typically implements one or more of the 2G, 3G, 4G, 5G, or higher cellular wireless communication technology standards. Depending on the technology standard implemented, a base station is designated as a gNodeB, eNodeB, NodeB, or base station.

[0098] A base station is a cellular network device used to communicate directly with user equipment operating in a cellular network over the air interface. Preferably, a base station is also connected to other cellular network components, particularly as part of a core network or a corresponding radio access network. Indirectly, each base station is connected to every other base station via such cellular network components.

[0099] A base station includes transmit and receive circuitry in combination with at least one antenna for wireless communications over an air interface.

[0100] It also includes processing circuitry for controlling the transmit and receive circuitry according to the communication protocol of the implemented technical standard(s).

[0101] Furthermore, the base station is preferably equipped with at least one memory unit, preferably a volatile and / or permanent memory, for storing operating system software, configuration data, for caching and logging, and the like.

[0102] The base station is configured to fill at least one frequency bandwidth, which is referred to as a supported frequency band in the following. Depending on whether the base station implements the time division duplex (TDD) or frequency division duplex (FDD) variant of the corresponding standard, there are either common (TDD) or separate supported frequency bands for uplink and downlink directions.

[0103] In particular, the individually supported frequency bands for uplink and downlink are deployed at a predefined frequency distance, referred to as a nominal spacing, which is in particular a value predefined in the corresponding technical standards.

[0104] The base station is capable of serving user equipments of reduced capabilities. These are those that are not capable of handling the full supported frequency band of the base station in at least one of the uplink or downlink directions.

[0105] To do so, the base station is configured to ascertain capability information from the served reduced-capability user equipment, in particular, indicating a capable uplink frequency bandwidth and / or a capable downlink frequency bandwidth. This may be the same value for both directions, or alternatively different.

[0106] Based on this, the base station is configured to perform scheduling for the corresponding user equipment and provide information on where the scheduling for the user equipment will be provided in the supported frequency band. Such a range can have a maximum size of the uplink and downlink frequency bands that can be used.

[0107] The second aspect shares the advantages of the first aspect of the invention.

[0108] According to a third aspect of the present invention, a method is proposed for a user equipment capable of operating with one of a plurality of base stations of a cellular network (hereinafter referred to as a serving base station), the user equipment being identified as a reduced-capability user equipment, the user equipment maintaining a capable uplink frequency bandwidth and a capable downlink frequency bandwidth, the method comprising the following steps:

[0109] - submitting capability information to the serving base station,

[0110] - receiving at least one first downlink signal from the serving base station,

[0111] - deriving an assignment of a scheduled uplink frequency band from said first downlink signal,

[0112] - determining the scheduled downlink frequency band by taking into account a predetermined nominal spacing of the centers of the scheduled uplink frequency band and the scheduled downlink frequency band,

[0113] - synchronously monitoring a scheduled downlink frequency band for signals from the base station, and transmitting at least one signal to the base station using a scheduled uplink frequency band.

[0114] This aspect of the invention relates to a method for a user equipment which is intended to operate with a base station according to the second aspect of the invention.

[0115] The user equipment is designated as a reduced-capability user equipment, meaning it is not capable of handling the full range of frequency bands supported by the base station. Therefore, to ensure continued service, it needs to operate differently with the support of the base station. This also includes full-duplex operation.

[0116] The user equipment maintains a capable uplink and downlink frequency bandwidth, which is the range of frequencies that the user equipment can handle, particularly due to the physical equipment and transceivers having the processing power.

[0117] Thus, according to the method, the user equipment makes capability information about the uplink and downlink frequencies that it is capable of using available to the serving base station, which is the base station on which the user equipment is currently camped.

[0118] This preferably occurs when starting camping on the base station or when registering.Alternatively or additionally, the information may be received by the base station from another base station, in particular a base station at which the user equipment was previously camped.

[0119] To perform a data exchange session, the user equipment needs to monitor the supported frequency bands of the user equipment, particularly in the downlink. However, since the user equipment does not have the ability to monitor the entire supported frequency band, it requires a scheduling indication that describes the range of the supported frequency bands of the base station, which is information required for the scheduling intended for the user equipment.

[0120] This is achieved by receiving a first downlink signal from the serving base station.This is submitted in a preferred predefined area that the user equipment monitors by default.

[0121] In the first downlink signal, the user equipment also extracts the assignment of the scheduled uplink frequency band. This is the frequency range over which the user equipment can transmit its data transmissions to the base station.

[0122] Alternatively, a first downlink signal is utilized which indicates a scheduled downlink frequency region, and within said scheduled downlink frequency region, an assignment to a scheduled uplink frequency band is transmitted.

[0123] In particular, the assignment is made to the center of the scheduled uplink frequency band.

[0124] The user equipment additionally needs to indicate the downlink communications that are expected to occur in parallel with potential uplink data transmissions, where such additional downlink scheduling is assumed to occur. There is no option to constantly remain in the scheduled frequency band for the first downlink signal.

[0125] However, signaling both the assignment of the scheduled uplink frequency band and the assignment of the scheduled downlink frequency band in parallel is also disadvantageous because it will increase the signaling for the base station to the relatively low priority user equipment.

[0126] Therefore, the method foresees that the user equipment derives the parallel scheduled downlink frequency band from the scheduled uplink frequency band indication at a predetermined nominal interval.

[0127] This nominal spacing is known to the user equipment and the base station. It is specifically assigned to the center of the scheduled uplink frequency band and delineates the center of the scheduled downlink frequency band.

[0128] Thus, the method of the present invention advantageously enables a reliable way for a base station to schedule a user equipment with reduced capabilities for duplex communication. This is achieved with low impact on the signaling of the cellular network and the power consumption of the user equipment.

[0129] Other embodiments are envisioned.

[0130] According to a fourth aspect of the present invention, a user equipment capable of operating with one of a plurality of base stations of a cellular network (hereinafter referred to as a serving base station) is provided, wherein the user equipment is identified as a reduced-capability user equipment, the user equipment maintains an uplink frequency bandwidth capable of use and a downlink frequency bandwidth capable of use, and the user equipment is configured to:

[0131] - submitting capability information to the serving base station,

[0132] - receiving at least one first downlink signal from the serving base station,

[0133] - deriving an assignment of a center of a scheduled uplink frequency band from said first downlink signal,

[0134] - determining the scheduled downlink frequency band by taking into account a predetermined nominal spacing of the scheduled uplink frequency band and the scheduled downlink frequency band,

[0135] - synchronously monitoring the scheduled downlink frequency band for signals from the base station, and transmitting at least one signal to the base station using the scheduled uplink frequency band.

[0136] This aspect of the invention relates to a user equipment.

[0137] The user equipment is capable of operating with a base station according to the second aspect of the invention. It is a reduced capability user equipment.

[0138] The user equipment comprises transmitting and receiving circuits in combination with at least one antenna for wireless communication with at least one base station, in particular a serving base station, over an air interface.

[0139] Preferably, the transmit and receive circuitry in the user equipment is incorporated into the transceiver. Furthermore, it is advantageous to equip the user equipment with a wireless modem that contains the transmit and receive circuitry, respectively, the transceiver, as well as all other hardware and software components necessary for wireless communication with the base station. The wireless modem is preferably also equipped with a call interface, at which the application part of the user equipment can control communications.

[0140] The user equipment further comprises at least one processing circuit, preferably a central processing unit (CPU) and / or a baseband processor. The at least one processing circuit is configured to control the transceiver to perform wireless communication. In addition, it is preferably configured to execute application logic, which may include, depending on the type of user equipment, handling of a user interface, collection and processing of measurement values ​​for submission to a remote server, handling of information or instructions received via a wireless communication connection, etc.

[0141] The user equipment further comprises a memory unit for volatile or permanent storage of operating software, communication protocol software, configuration data, application data, etc.

[0142] The fourth aspect shares the advantages of the third aspect of the invention.

[0143] As shown, the present invention advantageously solves the described problems and proposes a reliable method for full-duplex communication of reduced capability user equipment with a base station without significant drawbacks or additional signaling effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0144] The following description and drawings set forth certain illustrative aspects in detail and are indicative of only some of the various ways in which the principles of the embodiments may be employed. The features and advantages of the present invention will become apparent upon reading the following description and drawings of advantageous embodiments given as illustrative, non-limiting examples.

[0145] Figure 1 A first exemplary scheduling of uplink and downlink communications between a base station and a user equipment showing the type to which the present invention applies as an embodiment;

[0146] Figure 2 a second exemplary schedule of uplink and downlink communications representing the type to which the present invention applies as an embodiment;

[0147] Figure 3 A sequence diagram according to an exemplary embodiment of the present invention is shown.

[0148] Figure 1 Schematically illustrated is a user equipment UE operating with a base station BS being part of a cellular network CN. The base station BS is in particular configured to comply with 2G, 3G, 4G, 5G and / or above cellular wireless communication standards.

[0149] The user equipment (UE) resides on the base station. It is a reduced-capability user equipment, meaning it is not capable of handling the fully supported downlink frequency band SDFB and / or supported uplink frequency band SUFB of the base station BS. In the context of 5G, and correspondingly NR, such reduced-capability devices are referred to as NR light or NR-REDCAP. This means that regardless of the reduced-capability qualification, reduced-capability user equipment can be expected to operate in full duplex. This makes this deployment different from, for example, NB-IoT, where duplex signaling is not possible.

[0150] The base station BS knows the frequency bandwidth CBW that the user equipment UE is capable of using, which CBW is preferably exchanged as part of the capability information during the initial procedure of camping on the base station.

[0151] The horizontal axis depicts the frequencies at which the deployment of the frequency bands SDFB and SUFB supported by the base station BS is shown.Here a Frequency Division Duplex (FDD) deployment is shown, which means that the supported uplink and downlink frequency bands are separated.

[0152] This separation is not arbitrary, but rather lies within a predetermined fixed distance, which represents a nominal spacing NMS. This fixed nominal spacing NMS is preferably derived from the correspondingly implemented technical standard, for example 3GPP TS 36.101 for LTE.

[0153] In order to serve a reduced capability user equipment UE, the base station BS performs the following steps, shown in vertical sequence, indicating time. This means that they are assumed to occur more or less in parallel, at the same height.

[0154] First, in step S1, the base station BS considers that at least one resident reduced-capability UE (thus complying with the UE's capable frequency bandwidth CBW) will monitor signals dedicated to said UE within a specific range that said UE can decode.

[0155] Preferably, this is deployed, at least for LTE deployments, very close to the Master Information Block (MIB), which anyway needs to be read by any resident user equipment, at least to always receive the latest system information and any other broadcast information.

[0156] Within the scope of this scheduling, the base station BS sends a first downlink signal for the user equipment UE for an upcoming data transmission session, the first downlink signal indicating an uplink assignment UA for the scheduled uplink frequency band SUB. This is an indication that the user equipment UE can perform data transmission in the uplink frequency band SUFB supported by the base station BS.

[0157] Such data transmission is expected to occur in parallel with downlink data transmission from the base station BS that the user equipment UE is expected to monitor.

[0158] To do this, it needs to make the scheduled downlink frequency band SDB available for the next time period since this does not remain constant.

[0159] This is achieved from the base station BS by deploying the scheduled downlink frequency band SDB at a constant distance according to a nominal spacing NMS from the scheduled uplink frequency band SUB.

[0160] Therefore, in step S2, both scheduling frequency bands in uplink and downlink directions are deployed and are assumed to be monitored by user equipment in the downlink and used for data transmission in the uplink.

[0161] As shown in step S3, at least one indication is transmitted by the base station. Here, a further uplink assignment UA is signaled to the user equipment UE within the scheduled downlink frequency band SDB.

[0162] This is followed by a new schedule for the next time period, where the deployment for the user equipment UE may change.

[0163] As shown for uplink transmission, the uplink assignment UA of step S4 shows a scheduled uplink frequency band SUB in a completely different region of supported uplink frequency bands SUFB.

[0164] Therefore, the scheduled downlink frequency band SDB is also moved considering the nominal spacing NMS.

[0165] By way of example, a regular scheduling by the base station BS is shown so that the user equipment can always ensure that a limited range of the frequency bandwidth CBW that the user equipment is capable of using is used for scheduling purposes.

[0166] exist Figure 2 In FIG. 1 , a second example of the invention applied in a similar manner to the previous one is shown.

[0167] Steps S11-S14 more or less correspond to Figure 1 Steps S1-S4.

[0168] However, in S13 a scheduled uplink frequency band SUB is indicated with the uplink assignment UA which is quite close to the edge of the uplink frequency band supported by the base station. Due to the total size of the frequency bandwidth, it fits completely into the supported uplink frequency band.

[0169] However, the corresponding parallel scheduled downlink frequency band SDB is larger in size than the scheduled uplink frequency band SUB. Due to the fixed distance of the nominal spacing NMS, this results in, as shown in step S14, parts of the scheduled downlink frequency band SDB protruding beyond the edge of the supported downlink frequency band SDFB.

[0170] In this case, in step S15, the scheduled downlink frequency band SDB is shifted to the edge of the supported downlink frequency band SDFB. This ensures that the entire scheduled downlink frequency band can be used in this step to ensure the possible data throughput, if necessary.

[0171] This effect is particularly noticeable for the next deployed scheduled uplink frequency band SUB in step S16. According to the uplink assignment UA, this is deployed right at the edge of the supported uplink frequency band SUFB. Furthermore, it is significantly smaller, likely due to the low amount of resources requested by the user equipment UE for uplink transmission.

[0172] This leads to the effect that by applying the nominal spacing NMS half of the actually obtained scheduled downlink frequency band SDB lies outside the supported downlink frequency band SDFB.

[0173] In step S17 this is mitigated by again shifting the resulting scheduled downlink frequency band SDB to the edge of the supported downlink frequency band SDFB.

[0174] This exemplary embodiment shows that scheduling in uplink and downlink direction is reliably ensured to be fully available for the user equipment UE.

[0175] Figure 3 Shown is a sequence diagram indicating signaling messages between a user equipment UE and a base station BS in an exemplary embodiment of the present invention.

[0176] The sequence starts with a message M1 , in particular in the course of a procedure performed for camping on a base station, wherein the user equipment sends capability information to the base station.

[0177] Specifically, during the registration process of a user equipment (UE), the base station sends a UE capability request to the user equipment. If the user equipment capabilities have not been forwarded by the previous serving base station, the capability request is issued by the cellular network. In the case of an initial attachment, the user equipment sends its capabilities to the base station as part of the network registration process.

[0178] In LTE, the user equipment's capabilities are typically maintained in the MME, i.e., as part of the NAS procedure TS 23.401, and performed, for example, via the RRC procedure TS 36.331. If the user equipment has changed its E-UTRAN radio access capabilities, it will request higher layers to initiate the necessary NAS procedures (see TS 23.401), which will result in the use of a new RRC connection to update the user equipment's radio access capabilities. There are also NR methods involving TS 38.331, TS.23.401, and communication is done through the AMF (Access and Mobility Management Function).

[0179] As a response to or in lieu of the initial registration, the user equipment submits its capabilities to the base station using a UE capabilities message M1. The UE capabilities message M1 includes all information related to the UE capabilities. This specifically relates to all frequency bands that the user equipment is capable of using, in both uplink and downlink directions.

[0180] Immediately after this message M1, or after some waiting time, in particular when the data transmission session expires, the base station BS sends a first downlink signal to the user equipment using a message M2. The user equipment knows which frequency range to monitor for this downlink signal message from the base station based on previously determined or defined information, for example in the Master Information Block MIB.

[0181] Part of the downlink signal M2 is the uplink assignment UA. Based on the uplink assignment UA the user equipment knows where in the supported uplink frequency range of the base station BS it can perform uplink transmissions.

[0182] In this embodiment, no uplink transmission is due, so no signal / message is sent from the user equipment to the base station.

[0183] However, the base station needs to perform parallel downlink transmissions to the user equipment. These need to be scheduled, and the user equipment UE needs to know where these downlink transmissions are scheduled.

[0184] This is achieved indirectly by the uplink assignment UA submitted with the message M2. By applying a constant nominal spacing at the center of the uplink assignment UA, the user equipment UE can easily derive the center of the scheduled downlink frequency band SDB. To this end, the user equipment UE uses the entire frequency bandwidth CBW that it is capable of using. However, due to other distribution rules, only a part of the scheduled downlink frequency bandwidth SDB can be used for scheduling instructions of the base station BS, and therefore the user equipment UE only listens to this part of the frequency band CBW that it is capable of using. For example, such a measure is known in LTE, in which all resident user equipment UE are distributed over the supported frequency ranges that they are capable of using, so that each user equipment listens to each frequency range equally frequently, and each frequency range is used equally frequently for scheduling of all user equipment UE.

[0185] If the scheduled downlink frequency band SDB is completely within the supported downlink frequency band SDFB of the base station BS, the user equipment UE is ready to monitor the data transmission of the base station BS within the scheduled downlink frequency band SDB with a message M3 until the data dedicated to the user equipment is submitted.

[0186] With message step M4 the user equipment UE performs said monitoring and decodes the signals or data packets dedicated to the user equipment UE.

[0187] In the above detailed description, reference is made to the accompanying drawings, which illustrate specific embodiments in which the present invention may be implemented. These embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention. It should be understood that the various embodiments of the present invention, although different, are not necessarily mutually exclusive. For example, a specific feature, structure or characteristic described herein in conjunction with one embodiment may be implemented in other embodiments without departing from the scope of the present invention. In addition, it should be understood that the position or arrangement of the individual elements within each disclosed embodiment may be modified without departing from the scope of the present invention. Therefore, the above detailed description should not be considered restrictive, and the scope of the present invention is limited only by the appended claims, properly interpreted, and the full range of equivalents to which the claims are entitled.

Claims

1. A method of operating a base station (BS) as part of a cellular network (CN), the base station serving a plurality of user equipments (UEs), the base station (BS) operating in at least one supported frequency band in the uplink direction and one supported frequency band in the downlink direction (SUFB, SDFB), wherein: The plurality of user equipments include at least one user equipment identified as a reduced-capability user equipment, wherein the base station (BS) is configured to ascertain capability information indicating a capable uplink frequency bandwidth and a capable downlink frequency bandwidth (CBW) from the reduced-capability user equipment, In order to schedule at least one reduced-capability user equipment (UE), the method comprises the following steps for a base station (BS): - transmitting, for said user equipment (UE), at least one first downlink signal indicating an assignment (UA) of a scheduled uplink frequency band (SUB), taking into account the received capability information, - Based on the centers of the scheduled downlink frequency band (SDB) and the scheduled uplink frequency band (SUB), scheduling information in the scheduled downlink frequency band (SDB) for transmission in synchronization with a predetermined nominal time interval (NMS) of the scheduled uplink frequency band (SUB).

2. The method according to claim 1, in, The step of transmitting at least one first downlink signal comprises indicating a scheduled downlink frequency band (SDB) and transmitting the assignment (UA) to a scheduled uplink frequency band (SUB) within the scheduled downlink frequency band.

3. The method according to any one of claims 1 or 2, in, Performing the step of transmitting the first downlink signal: - based on a predetermined proximity around a Master Information Block (MIB), or - as announced by the base station (BS) in broadcast signalling, or - in a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence taking into account user equipment specific elements, or - In a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence taking into account frame timing relations.

4. The method according to any one of claims 1 to 2, further comprising the step of determining whether the scheduled downlink frequency band (SDB) exceeds the supported downlink frequency band (SDFB), If yes, the scheduling is modified by shifting the scheduled downlink frequency band (SDB) to the edge of the supported downlink frequency band (SDFB).

5. The method according to any one of claims 1 to 2, in, In case the base station (BS) operates in time domain duplexing, the nominal spacing (NMS) is zero.

6. The method according to any one of claims 1 to 2, The method further includes determining a second scheduled downlink frequency band (SDB) after performing uplink transmission considering the scheduled uplink frequency band (SUB), considering at least one of the following: - a predetermined proximity around a Master Information Block (MIB), - Broadcast signaling, - a portion of said supported downlink frequency band (SDB) identified by a frequency hopping sequence, - The previously used scheduled downlink band (SDB).

7. A base station (BS), the base station (BS) being part of a cellular network, the base station (BS) being configured to serve a plurality of user equipments, the base station (BS) operating in at least one supported frequency band in an uplink direction and in one supported frequency band in a downlink direction, wherein The plurality of user equipments include at least one user equipment identified as a reduced-capability user equipment, wherein the base station (BS) is configured to ascertain capability information indicating a capable uplink frequency bandwidth and a capable downlink frequency bandwidth (CBW) from the reduced-capability user equipment (UE), In order to schedule at least one user equipment (UE) with reduced capability, the base station (BS) is configured to: - transmitting at least one first downlink signal for said user equipment (UE) taking into account the received capability information indicating an assignment (UA) to a scheduled uplink frequency band (SUB), - Based on the centers of the scheduled downlink frequency band (SDB) and the scheduled uplink frequency band (SUB), scheduling information in the scheduled downlink frequency band (SDB) for transmission in synchronization with a predetermined nominal time interval (NMS) with the scheduled uplink frequency band (SUB).

8. The base station (BS) according to claim 7, in, Said transmission of at least one first downlink signal comprises indicating a scheduled downlink frequency band (SDB), and transmitting said assignment (UA) to a scheduled uplink frequency band (SUB) within said scheduled downlink frequency band (SDB).

9. The base station (BS) according to any one of claims 7 or 8, in, Said transmission of the first downlink signal is performed as follows: - based on a predetermined proximity around a Master Information Block (MIB), or - as announced by the base station (BS) in broadcast signalling, or - in a portion of the supported downlink frequency band (SDFB) identified by a hopping sequence taking into account a user equipment (UE) specific element, or - In a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence taking into account frame timing relations.

10. The base station (BS) according to any one of claims 7 to 8, is further configured to determine whether the scheduled downlink frequency band (SDB) exceeds the supported downlink frequency band (SDFB), If yes, the scheduling is modified by shifting the scheduled downlink frequency (SDB) band to the edge of the supported downlink frequency band (SDFB).

11. The base station (BS) according to any one of claims 7 to 8, The method is further configured to determine, after performing uplink transmission taking into account the scheduled uplink frequency band (SUB), a second scheduled downlink frequency band (SDB) taking into account at least one of the following: - a predetermined proximity around a Master Information Block (MIB), - Broadcast signaling, - a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence, - The previously used scheduled downlink band (SDB).

12. A method for a user equipment (UE) capable of operating with one of a plurality of base stations (BS) of a cellular network (CN), the one base station being hereinafter referred to as a serving base station, the user equipment (UE) being identified as a reduced-capability user equipment, the user equipment (UE) maintaining a capable uplink frequency bandwidth and a capable downlink frequency bandwidth (CBW), The method comprises the following steps: - Submit capability information to the serving base station (BS), - receiving at least one first downlink signal from a serving base station (BS), - deriving an assignment (UA) of a scheduled uplink frequency band (SUB) from the first downlink signal, - determining the scheduled downlink frequency band (SDB) by taking into account a predetermined nominal spacing (NMS) of the centers of the scheduled uplink frequency band (SUB) and the scheduled downlink frequency band (SDB), - synchronously monitoring a scheduled downlink frequency band (SDB) for a signal from a base station (BS), and transmitting at least one signal to the base station (BS) using a scheduled uplink frequency band (SUB).

13. The method according to claim 12, in, The step of receiving the at least one first downlink signal is performed as follows: - based on a predetermined proximity around a Master Information Block (MIB), or - as announced by the base station (BS) in broadcast signalling, or - In a portion of a supported downlink band (SDB) identified by a hopping sequence taking into account user equipment (UE) specific elements.

14. The method according to any one of claims 12 or 13, further comprising the step of determining whether the scheduled downlink frequency band (SDB) exceeds the supported downlink frequency band (SDFB), If yes, the scheduled downlink frequency band (SDB) is shifted to the edge of the supported downlink frequency band (SDFB).

15. The method according to any one of claims 12 or 13, The method further includes determining a second scheduled downlink frequency band (SDB) by considering at least one of the following after performing uplink transmission considering the scheduled uplink frequency band (SUB): - a predetermined proximity around a Master Information Block (MIB), - Broadcast signaling, - a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence, - The previously used scheduled downlink band (SDB).

16. A user equipment (UE) capable of operating with one of a plurality of base stations (BS) of a cellular network (CN), the one base station being hereinafter referred to as a serving base station (BS), the user equipment (UE) being designated as a reduced-capability user equipment, the user equipment (UE) maintaining a capable uplink frequency bandwidth and a capable downlink frequency bandwidth (CBW), The user equipment (UE) is configured to: - Submit capability information to the serving base station (BS), - receiving at least one first downlink signal from a serving base station (BS), - deriving an assignment (UA) of a scheduled uplink frequency band (SUB) from the first downlink signal, - determining the scheduled downlink frequency band (SDB) by taking into account a predetermined nominal spacing (NMS) of the centers of the scheduled uplink frequency band (SUB) and the scheduled downlink frequency band (SDB), - synchronously monitoring a scheduled downlink frequency band (SDB) for a signal from a base station (BS), and transmitting at least one signal to the base station (BS) using a scheduled uplink frequency band (SUB).

17. The user equipment (UE) according to claim 16, in, Said receiving of at least one first downlink signal is performed as follows: - based on a predetermined proximity around a Master Information Block (MIB), or - as announced by the base station (BS) in broadcast signalling, or - In a portion of the supported downlink frequency band (SDFB) identified by a frequency hopping sequence taking into account user equipment (UE) specific elements.

18. The user equipment (UE) according to any one of claims 16 or 17, is further configured to determine whether the scheduled downlink frequency band (SDB) exceeds the supported downlink frequency band (SDFB), If yes, the scheduled downlink frequency band (SDB) is shifted to the edge of the supported downlink frequency band (SDFB).

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