Method, user equipment, and base station for establishing communication using inter-band carrier aggregation

Abstract

The present application relates to a method, a user equipment, and a base station for establishing communication using inter-band carrier aggregation. A method, performed in a user equipment UE (1), for establishing communication with a radio network (100) using inter-band carrier aggregation CA, the method comprising the steps of: sending (610) to the radio network information identifying the ability (51) of the UE to perform beam management for multiple component carriers CC; receiving (612) from a base station (110) of the radio network information (52) indicating co-location characteristics of a first CC in a first frequency band and a second CC in a second frequency band, based on the ability; and establishing (617) communication between the UE (1) and the radio network (100) using the first CC and the second CC.

Description

Technical Field

[0001] The present disclosure relates to methods and apparatuses for establishing communication with a wireless network using inter-band Carrier Aggregation. More specifically, solutions for identifying terminal capabilities to improve communication establishment are provided. Background Art

[0002] Radio communication systems operating under various iterations of the Third Generation Partnership Project (3GPP) provide high peak data rates, low latency, improved system capacity, and low operating costs resulting from a simple network architecture. These systems include, in particular, Long Term Evolution (LTE) systems and more recently the so-called 5G networks and New Radio (NR). Orthogonal Frequency Division Multiplexing (OFDM) radio technology has been incorporated to enable efficient transmission of high data bandwidths while still providing a high degree of resilience to reflections and interference. In such radio communication systems, the transmit power of each wireless terminal (also referred to as a User Equipment (UE)) needs to be maintained at a certain level and regulated by the network. The base station or access node of a 5G wireless network is referred to as a gNB. The actual transmit and receive points of the base station are referred to herein as Transmission (Transmit and Receive) Points (TRP). A TRP can be considered to include the antenna system of the base station or a network node co-located with the antenna system of the base station.

[0003] When operating a UE at mmWave frequencies (such as in NR), the function of beamforming is necessary because it (as opposed to omnidirectional transmission) allows for directional transmission to improve the signal-to-noise ratio. This has become more relevant as wireless communication enters the mmWave frequency range (e.g., Frequency Range 2 (FR2) including the frequency range from 24250 MHz to 52600 MHz), where spatial filters and antennas can be used to transmit at finer cone angles. However, at higher frequencies, this range decreases. Network vendors have expressed interest in co-located and non-co-located deployments of TRPs, especially those operating in the 28 GHz band and 39 GHz band and covering the same area. The reason is that 39 GHz and 28 GHz have different coverage characteristics, and thus, compared to 28 GHz, 39 GHz will require a denser gNB deployment.

[0004] Figure 1A and Figure 1B Illustrates possible deployment scenarios for TRP 10 to TRP 13. At the respective TRPs, the larger boxes indicate the 28 GHz TRPs, while the smaller boxes indicate the 39 GHz TRPs. For example, TRP 10 includes co-located TRP 10A at 28 GHz and TRP 10B at 39 GHz. TRP 12 and TRP 13 provide similar co-locations.Figure 1A illustrates the coverage from the respective TRP at 39 GHz, while Figure 1B illustrates the coverage from the respective TRP at 28 GHz. Due to the poorer coverage at higher frequencies, for 39 GHz, an additional base station at TRP 11 is required to cover the intermediate area.

[0005] However, such a deployment also results in more complex beam management for inter-band carrier aggregation (CA) operations, especially when the frequency band separation is as large as 11 GHz. Therefore, improvements are needed in the field of inter-band CA, especially when the TRPs in different frequency bands can be co-located or not co-located. SUMMARY OF THE INVENTION

[0006] Solutions to meet the aforementioned improvement needs are provided in the independent claims, while advantageous embodiments are set forth in the dependent claims.

[0007] According to one aspect, a method for establishing communication with a wireless network using inter-band CA and executed in a UE is provided. The method includes the following steps:

[0008] Sending information to the wireless network identifying the UE's ability to perform beam management for multi-CC;

[0009] Receiving, according to the ability, information from a base station of the wireless network indicating the co-location characteristic of a first CC in a first frequency band and a second CC in a second frequency band;

[0010] Establishing communication between the UE 1 and the wireless network using the first CC and the second CC.

[0011] A corresponding solution for a base station of a wireless network to establish communication with a UE using inter-band CA is provided, which includes:

[0012] Obtaining information identifying the UE's ability to perform beam management for multi-component carrier CC;

[0013] Sending, according to the ability, information to the UE, where the information indicates the co-location characteristic of a first CC in a first frequency band and a second CC in a second frequency band;

[0014] Establishing communication on the first CC and the second CC.

[0015] The proposed method provides reduced signaling overhead, especially in the sense that the network is configured to provide relevant data for inter-band CA to the UE based on its ability level in this regard. The proposed solution also provides for the network to provide an appropriate allocation of TRPs based on the UE's implementation, as reflected in the CA capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A and Figure 1B schematically illustrates the deployment of a TRP for coverage on different mmWave frequency bands of a wireless network.

[0017] Figure 1C schematically illustrates beams that can be used for communication between a UE and various TRPs of a wireless network.

[0018] Figure 2 schematically illustrates a wireless network according to various embodiments and communication between a UE and respective base stations using CA.

[0019] Figure 3 schematically illustrates a UE configured to operate according to various embodiments.

[0020] Figure 4 schematically illustrates a base station configured to operate according to various embodiments.

[0021] Figure 5 schematically illustrates a signaling diagram for establishing communication between a wireless network and a UE using inter-band CA according to various embodiments.

[0022] Figure 6 schematically illustrates a flowchart of a method for establishing communication using inter-band CA, which is executed in a UE according to various embodiments.

[0023] Figure 7 schematically illustrates a flowchart of a method for establishing communication using inter-band CA, which is executed in a base station according to various embodiments. Detailed Embodiments

[0024] In the following description, for purposes of explanation and not limitation, details related to various embodiments are set forth. However, those skilled in the art will appreciate that the present invention may be practiced in other embodiments without these specific details. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. The functions of various components including functional modules can be provided by hardware such as circuit hardware and / or hardware capable of executing software in the form of encoded instructions stored on a computer-readable medium, the functional modules including but not limited to those labeled or described as "computer", "processor", or "controller". Accordingly, these functions and the illustrated functional modules are to be understood as being implemented by hardware and / or implemented by a computer and thus implemented by a machine. As for hardware implementation, the functional modules may include or encompass but are not limited to, digital signal processor (DSP) hardware, reduced instruction set processors, hardware (e.g., digital or analog) circuits including but not limited to application specific integrated circuits [ASIC], and (where appropriate) state machines capable of performing such functions. As for computer implementation, a computer is generally understood to include one or more processors or one or more controllers, and the terms computer and processor and controller may be used interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by multiple separate computers or processors or controllers, some of which may be shared or distributed. Moreover, the use of the term "processor" or "controller" should also be construed to refer to other hardware capable of performing such functions and executing software, such as the example hardware set forth above.

[0025] The drawings are to be regarded as being schematic representations and elements illustrated in the drawings need not be shown to scale. Instead, the various elements are represented such that their function and general purpose will be apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. The couplings between components may also be established through wireless connections. The functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0026] As shown, beam management is a complex process in inter-band CA because UE capabilities and network deployments must be very flexible for inter-band CA to function. UEs capable of inter-band CA can benefit from, for example, Figure 1A and Figure 1BThe illustrated deployments. However, whether a particular UE can receive and / or transmit data simultaneously over two frequency bands will depend on the UE's RF architecture, which is up to the UE manufacturer. Depending on the level of UE support, different scenarios for inter-band carrier aggregation can be foreseen. Some scenarios are discussed in the Rel.17 time frame, and others are likely to be proposed in future releases. This is shown in Table 1 below, which indicates the capabilities of inter-band CA with co-located and non-co-located TRP deployments, based on the beam management (BM) support of the UE RF architecture. Combinations marked with (*) are more likely to be considered. In this table, "partially capable" means supported (partially) by the relevant UE RF architecture.

[0027]

[0028] Table 1

[0029] Here, independent BM means that the UE can use any beam or spatial filtering on each CC to transmit and / or receive simultaneously over multiple component carriers (CCs). This capability requires the UE to have at least two independent sets of phase shifters, which results in better beam management flexibility but also higher power consumption.

[0030] Figure 1C Illustrated both UE 1 and UE 2 in a wireless network deployment such as Figure 1A and Figure 1B The UE RF architecture can enable approximately the same transmit / receive directions to be obtained over multiple CCs, and the spherical coverage of the CCs mainly overlaps. This is illustrated by UE 2 in Figure 1C Generally, such a UE architecture is very suitable for deployment with co-located TRPs such as TRP 12A and TRP12B, where the signals propagate in similar directions. The performance of non-co-located TRPs depends on other factors such as the density of TRP deployment and the spherical coverage percentage. Alternatively, the UE RF architecture can greatly reduce the set of overlapping directions, and the spherical coverage of the CCs is mainly non-overlapping, as shown by UE 1 in Figure 1C Normally, such a UE architecture works well in non-co-located TRP deployments where the signals propagate in very different directions, but it works poorly for co-located TRPs.

[0031] A non - stand - alone BM means that the UE has only one set of fully controllable phase shifters across the entire frequency range of CA. Therefore, it can only transmit and / or receive via multiple CCs using beams pointing in similar directions (aligned non - stand - alone BM) or beams pointing in different directions that are fixed relative to each other (unaligned non - stand - alone BM). In other words, once the UE beam direction in one frequency band is selected, the beam direction in the other frequency band will be fixed relative to the first frequency band. This configuration is the traditional configuration of current commercial phones in FR2. Since there is only one degree of freedom to control the direction of the beams on multiple CCs, such a UE architecture can be expected to work well only when the beams on multiple CCs are aligned and the TRPs are co - located.

[0032] In previous versions of the standard that outline the technical specifications of CA, the UE was able to signal to the network in the concerned frequency band whether it has the ability of inter - band CA. At registration, this information can be conveyed as the UE radio capabilities sent from the UE to the network or as an ID representing such UE radio capabilities as described above. This may lead to a situation where the network attempts to establish a connection using inter - band CA that may not actually work for the UE. Given the actual deployment with co - located or non - co - located TRPs, the lack of prior knowledge about whether inter - band CA will work for a particular UE may thus result in signaling overhead.

[0033] For these reasons, the solution proposed in this paper is used to improve the establishment of communication using inter - band CA. This involves the concept of conveying from the UE to the radio network such information that identifies the UE's ability to perform beam management for multiple CCs, thus informing the network of the level of inter - band CA it can support.

[0034] Figure 2A wireless communication system is schematically illustrated that includes a wireless network 100 and a UE (or terminal) 1 configured to communicate wirelessly with the wireless network 100. The wireless network can be a radio communication network operating under general and specific provisions and restrictions published by 3GPP, such as a new radio (NR) network that can operate under FR 2 in different mmWave frequency bands. The wireless network 100 can include a core network 101 that is connected to other networks 120, such as the Internet. The wireless network 100 also includes an access network 102 that includes a plurality of base stations or access nodes 110, 111. A base station is an entity that performs a wireless connection with the UE. Thus, each of the base stations 110, 111 includes or is connected to a transmission point TRP 10, TRP 11, which includes an antenna arrangement for transmitting and receiving radio signals. The base stations 110, 111 can be gNBs and are configured for beamforming as introduced for 5G. The figure further illustrates a network node 103 that can incorporate functions for managing communication and cooperation with the base stations 110, 111, such as user plane functions. In various embodiments, a logical communication interface can be provided between the base stations 110, 111.

[0035] UE 1 can be any device operable to communicate wirelessly with the network 100 via the base stations 110, 111, such as a mobile phone, computer, tablet, M2M device, or other device. UE 1 is configured to communicate with more than one beam, which are preferably orthogonal in terms of code division and / or frequency division and / or time division. The beam configuration in UE 1 can be achieved by using such an antenna array, i.e., the communication quality is configured to provide an anisotropic sensitivity distribution map for transmitting radio signals along a specific transmission direction.

[0036] Figure 3 An embodiment of UE 1 is schematically illustrated for use in the wireless network 100 as presented herein and for performing the outlined method steps.

[0037] The terminal UE 1 can include a radio transceiver 313 for communicating with other entities of the radio communication network 100 (such as the base stations 110, 111) in different mmWave frequency bands. The transceiver 313 can thus include a radio receiver and a transmitter for communicating via at least one air interface.

[0038] UE 1 further includes a logic 310 configured to transmit data to the wireless communication network 100 via the radio transceiver over a wireless channel and possibly directly to another terminal UE1 via device-to-device (D2D) communication.

[0039] Logic 310 may include a processing device 311, which includes one or more processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. The processing device 311 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an application-specific integrated circuit (ASIC), etc.). The processing device 311 may be configured to perform one or more operations based on an operating system and / or various applications or programs.

[0040] Logic 310 may further include a memory storage device 312, which may include one or more memories and / or one or more other types of storage media. For example, the memory storage device 312 may include: random access memory (RAM), dynamic random access memory (DRAM), cache memory, read-only memory (ROM), programmable read-only memory (PROM), flash memory, and / or some other type of memory. The memory storage device 312 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optical disk, a solid-state disk, etc.).

[0041] The memory storage device 312 is configured to store computer program code that can be executed by the processing device 311, wherein the logic 310 is configured to control the UE 1 to execute any method steps provided herein. The software defined by the computer program code may include an application or program that provides functions and / or processing. The software may include: device firmware, an operating system (OS), or various applications that can be executed in the logic 310.

[0042] The terminal UE 1 may further include an antenna 314, which may include an antenna array. The logic 310 may also be configured to control a radio transceiver to adopt the anisotropic sensitivity distribution map of the antenna array to transmit radio signals in a specific transmission direction. In various embodiments, this may involve applying a transmit spatial filter 315A to adapt the spatial sensitivity of the antenna 314, especially in UL transmission; and applying a receive spatial filter 315B to adapt the spatial sensitivity of the antenna 314, especially in DL reception. Depending on the implementation, the spatial filters 315A, 315B may include multiple sets of phase shifters, which may be independent, thereby allowing any beam on each CC to be used for simultaneous transmission and / or reception over multiple CCs during CA.

[0043] Obviously, the terminal may include other features and elements other than those shown in the drawings or described herein, such as a power supply, a housing, a user interface, one or more sensors (such as a proximity sensor, an accelerometer, a magnetometer, etc.) configured to sense and detect the orientation or proximity of another object (such as the user of the UE 1), etc.

[0044] Figure 4 Schematically illustrated is base station 110, which is for use in radio communication network 100 as presented herein and is configured to perform the method steps as outlined. It should be noted that Figure 4 the embodiments of... can equally be used for second base station 111.

[0045] Base station 110 comprises or operates as a base station (such as a gNB) of radio communication network 100, which is configured to operate in different mmWave frequency bands. Base station 110 may include a radio transceiver 413 for communicating with other entities (such as UE 1) of radio communication network 100. Transceiver 413 may thus include a radio receiver and a transmitter for communicating via at least one air interface.

[0046] Base station 110 further includes logic 410, which is configured to transmit data to UE 1 via the radio transceiver over a radio channel. Logic 410 may include processing means 411, comprising: one or more processors, microprocessors, data processors, co-processors, and / or some other type of component for interpreting and / or executing instructions and / or data. Processing means 411 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an application-specific integrated circuit (ASIC), etc.). Processing means 411 may be configured to perform one or more operations based on an operating system and / or various applications or programs.

[0047] Logic 410 may further include a memory storage device 412, which may include one or more memories and / or one or more other types of storage media. For example, memory storage device 412 may include: random access memory (RAM), dynamic random access memory (DRAM), cache memory, read-only memory (ROM), programmable read-only memory (PROM), flash memory, and / or some other type of memory. Memory storage device 412 may include: a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optical disk, a solid-state disk, etc.).

[0048] Memory storage device 412 is configured to store computer program code executable by processing means 411, wherein logic 410 is configured to control base station 110 to perform any of the method steps provided herein. The software defined by the computer program code may include applications or programs providing functions and / or processing. The software may include: device firmware, an operating system (OS), or various applications executable in logic 410.

[0049] The base station 110 may also include or be connected to an antenna 414, which is connected to a radio transceiver 413, and the antenna may include an antenna array. The logic 410 may also be configured to control the radio transceiver to use the anisotropic sensitivity distribution map of the antenna array to transmit and / or receive radio signals in a specific transmission direction. In various embodiments, this may involve applying a transmit spatial filter 415A to adapt the spatial sensitivity of the antenna 414 especially in DL transmission; and applying a receive spatial filter 415B to adapt the spatial sensitivity of the antenna 414 especially in UL reception. The base station 110 or alternatively only the antenna 414 may form the transmission point TRP of the base station 110.

[0050] The base station 110 may also include a communication interface 416, which is operable to enable the base station to communicate with other nodes of the wireless network 100 (such as a higher network node 103) or with another base station 111.

[0051] In various embodiments, the base station 110 is configured to perform the method steps described for execution in a base station or for controlling a TRP, as outlined herein.

[0052] Now, various embodiments will be described with reference to Figures 5 to 7 to. Figure 6 and Figure 7 illustrates a process flow diagram, while Figure 5 shows a signaling diagram of at least some embodiments among the embodiments within the scope of the general method shown in Figure 6 and Figure 7 .

[0053] Referring to Figure 6 , according to one aspect, a method for establishing communication with the wireless network 100 using inter-band CA in the UE 1 is provided. The method includes the following steps:

[0054] Transmit 610 information indicating the ability 51 of the UE to perform beam management for multiple CCs to the wireless network;

[0055] Receive 612 from the base station 110 of the wireless network information 52 indicating the co-location characteristics of a first CC in a first band and a second CC in a second band according to the ability;

[0056] Establish 617 communication between the UE 1 and the wireless network 100 using the first CC and the second CC.

[0057] Referring to Figure 7 , according to another aspect, a method for establishing communication with the UE 1 using inter-band CA in the base station 110 of the wireless network 100 is provided, and the method includes the following steps:

[0058] Obtain information indicating the ability of the UE with identifier 710 to perform beam management for a multi-component carrier (CC);

[0059] According to the ability, send information 52 of 712 to the UE, where the information indicates the co-location characteristics of a first CC in a first frequency band and a second CC in a second frequency band;

[0060] Establish communication 718 on the first CC and the second CC.

[0061] In the sense of configuring network 100 to provide relevant data for inter-band CA to UE 1 based on its ability level in this regard, the proposed method provides reduced signaling overhead. The proposed solution also provides for an appropriate allocation of the TRP by network 100 based on the implementation of UE 1, as reflected in the CA capabilities. Examples of implementations and embodiments will be provided in the following sections.

[0062] The information indicating the ability 51 can be included in the UE radio capabilities, such as provided by UE 1 to network 100 when registering with the network. Alternatively, UE 1 can send an ability ID as the information, which identifies the associated UE radio capabilities that can be obtained from a database in or connected to network 100. Such an ability ID can be, for example, manufacturer-specific and defined by the UE manufacturer or vendor, or PLMN-specific and defined by the operator of network 100. Various forms of defining and transmitting the ability ID can be performed, as provided under the 3GPP concept of RACS (Radio Access Capability Signaling).

[0063] In various embodiments, the ability 51 can identify the communication ability to use CA and can directly or indirectly specify in which frequency bands and / or which frequency band combinations different CCs can be supported during CA. In some embodiments, the ability 51 can identify the ability to perform independent beam management within a common spherical region. This can be provided in the capabilities regarding frequency band combinations (such as on a first frequency band and a second frequency band).

[0064] Based on the inter-band CA capability 51, the base station 110 can be configured to send information 52 to the UE 1, which indicates the co-location characteristic. In this regard, the information 52 can depend on the inter-band CA capability 51, such that different information 52 is sent according to what inter-band CA capabilities the UE 1 has. In some embodiments, the information 52 is sent only in response to the capability 51 indicating a positive capability regarding inter-band CA, for example, one of the following positive capabilities: the positive capability to communicate using inter-band CA on a first frequency band and a second frequency band, the positive capability to perform independent beam management on a first frequency band and a second frequency band, or the positive capability to perform independent beam management within a common spherical region on a first frequency band and a second frequency band, or the positive capability to perform aligned non-independent beam management on a first frequency band and a second frequency band. For any UE implementation having one of these capabilities, the establishment of inter-band CA communication can benefit from the network 100 obtaining this information of the capability 51.

[0065] In one example, the UE 1 is configured to signal to the network 100 information about its capability 51, which reflects the ability to perform independent beam management on the same coverage area (e.g., within the same spherical sector). Thus, the network 100 can be configured to allocate co-located TRPs, for example, for better inter-band CA performance and reduced signaling overhead.

[0066] In another example, the UE 1 is configured to signal to the network 100 information about its capability 51, which reflects the ability to perform independent beam management on different coverage areas (e.g., in diametrically opposite spherical sectors). Thus, the network 100 can be configured to allocate non-co-located TRPs for better inter-band CA performance and reduced signaling overhead.

[0067] In yet another example, the UE 1 is configured to signal to the network 100 information about its capability 51, which reflects the ability to perform aligned non-independent beam management for inter-band CA on multiple CCs. Thus, the network 100 can be configured to allocate co-located TRPs for better inter-band CA performance and reduced signaling overhead.

[0068] In some embodiments, the information 52 indicating the co-location characteristic indicates the co-location of a first TRP for a first CC and a second TRP for a second CC (such as TRP 12A and TRP 12B). In various embodiments, this information can be conveyed in the DL signaling as a single bit indicating whether co-located or a combination of bits indicating more information.

[0069] In some embodiments, receiving 612 information 52 indicating co-location characteristics includes receiving such information from the network, where the information identifies the frequency bands of the first CC and the second CC that are destined to be used for CA.

[0070] In some embodiments, receiving 612 information 52 indicating co-location characteristics of a first CC in a first frequency band and a second CC in a second frequency band includes: obtaining 613 an instruction to use a common DL transmission configuration indicator (TCI) state for all CCs for which CA communication is to be established.

[0071] In various versions of such embodiments, the step of obtaining the instruction includes:

[0072] Sending 614 a request to the base station to use a common DL TCI state for all CCs for reception 714 in network 100; and

[0073] Receiving 616 an instruction sent 716 from network 100 that identifies approval to use the common DL TCI state. In such an embodiment, the instruction may be an ACK of the request to use a common DL TCI state for all CCs.

[0074] In some embodiments, the received information 52 indicates that the DL TCI state of the CCs for which CA communication is to be established is quasi-co-located (QCL). In a variant of this embodiment, if the QCL indication is rank 1 or rank 2, then information 52 may be provided. In a line-of-sight (LOS) mmWave link, rank 2 is typically used to transmit two streams based on polarization MIMO. By including rank information in the QCL indication, the UE can be informed whether the aggregated QCL beams carry one polarization or two polarizations.

[0075] In various embodiments, thus, the UE 1 can be configured to obtain a first CC and a second CC having the same DL TCI state.

[0076] In various embodiments, establishing 617 may include:

[0077] Determining 618 a first beam in a first frequency band by performing a beam search; and

[0078] Determining 620 a second beam in a second frequency band based on the beam search and the information.

[0079] For example, if information 52 indicates that the first CC and the second CC are co-located, then knowing the determination of the first beam indicates in what direction the second beam should be determined.

[0080] Returning to the basis of the proposed solution and referring to the accompanying drawings and the disclosure of the general solution and implementations outlined herein, the deployment of the base station and the TRP can be co-located and non-co-located for inter-band CA. Thus, in various implementations, the working assumption is that independent beam management will be achieved for inter-band CA operation as a baseline.

[0081] In an exemplary implementation based on this assumption, the base station 110 (e.g., gNB) signals (i.e., transmits 712) to the UE 1 information 52 as to whether the TRPs 10A and 10B / 11 for the multiple CCs (e.g., 28 GHz and 39 GHz) of the inter-band CA are co-located. The purpose of the signaling is in particular to simplify beam management for inter-band CA in co-located scenarios. Additionally or alternatively, the base station 110 signals 716 to the UE 1 that the DL TCI state common to all CCs in the CA will be used. This latter signaling can also be initiated 614 by the UE 1 when it learns that the TRPs for the multiple CCs of the inter-band CA are co-located and wishes to simplify DL TCI state management.

[0082] If the TRPs are co-located (such as 10A, 10B), and the UE 1 can support independent beam management for the overlapping regions, the UE 1 does not need to perform beam search for all CCs. It can instead be configured to perform beam search on one CC and then subsequently use beams with similar spatial characteristics on the other CCs.

[0083] If the TRPs 10A, 10B are co-located, the management of the DL TCI state can be simplified by noting that they are QCL in the information 52. In this case, the signaling overhead can be reduced.

[0084] If the UE 1 cannot perform independent beam management for each CC, the base station 110 can establish communication with the UE through the primary CC and can configure the UE 1 to transmit an uplink pilot through the secondary CC. The base station can be configured to select the corresponding beam for the secondary CC based on the received uplink pilot.

[0085] Referring to Figure 5 , an exemplary signaling diagram is shown that illustrates one use case of the overall solution provided herein. Note that this example is provided in a simplified manner, where only one base station 110 is shown. As will be understood by those skilled in the art, in some aspects, the base station 110 represents the network 100 or the access network 102, i.e., at least two base stations 110 and 111.

[0086] UE 1 notifies 501 the network 100 of its capabilities 51. This can be performed using any base station of the network 100 that receives 502 and is prepared to store the capabilities 51 in the network 100. The capabilities indicate that UE 1 is capable of independent beam management for inter-band CA. The base station 110 (e.g., gNB) can use this capabilities notification to decide whether to schedule UE 1 for inter-band CA based on the actual deployment of the TRP in the relevant frequency bands.

[0087] At a certain point in time, the serving base station 110 initiates the scheduling 503 of inter-band CA using at least a first CC and a second CC. The configuration of the scheduling is performed according to the obtained CA capabilities of UE 1.

[0088] Therefore, the base station 110 notifies UE 1 that the TRP10A and TRP 10B in the relevant frequency bands are co-located by sending 504 the information 52 indicating the co-location characteristics.

[0089] Based on the received 505 information 52, UE 1 is configured to reduce the signaling overhead by deciding 506 to use a common DL TCI state for the frequency bands of the CCs.

[0090] For this purpose, UE 1 sends 507 a request 53 in order to be received 508 by the base station 110.

[0091] The base station 110 grants the request 53, for example, by sending an acknowledgement 54 to UE 1.

[0092] After receiving 510 the acknowledgement, UE 1 can obtain the CCs to establish inter-band CA with a common DL TCI state.

[0093] Various embodiments have been outlined previously, and it should be noted that, unless they are self-contradictory, those embodiments can be combined with each other in any constellation, including those outlined in the appended claims.

Claims

1. A method for establishing communication with a radio network (100) using inter-band carrier aggregation (CA) in a user equipment (UE) (1), the method comprising the steps of: Sending (610) to the radio network information identifying the UE's ability (51) to perform beam management for multiple component carriers (CCs); Receiving (612) from a base station (110) of the radio network information (52) indicating the co-location characteristics of a first CC in a first frequency band and a second CC in a second frequency band, based on the ability; Establishing (617) communication between the UE (1) and the radio network (100) using the first CC and the second CC.

2. The method according to claim 1, wherein, The information indicating the co-location characteristics is received based on an ability that indicates an affirmative ability to perform independent beam management on the first and second frequency bands.

3. The method according to claim 2, wherein, The information indicating the co-location characteristics is received based on an ability that indicates an affirmative ability to perform independent beam management within a common spherical region on the first and second frequency bands.

4. The method according to claim 1, wherein, The information indicating the co-location characteristics is received based on an ability that indicates an affirmative ability to perform aligned non-independent beam management on the first and second frequency bands.

5. The method according to any one of claims 1 to 4, wherein The received information indicates that the first CC and the second CC are co-located.

6. The method according to any one of claims 1 to 4, wherein The step of establishing (617) includes: Determining (618) a first beam in the first frequency band by performing a beam search; Determining (620) a second beam in the second frequency band based on the beam search and the information.

7. The method according to any one of claims 1 to 4, wherein The received information (52) indicates the co-location of a first transmission point (TRP) of the first CC and a second TRP of the second CC.

8. The method according to claim 1, the method comprising the steps of: Obtaining (616) an instruction to use a common downlink transmission configuration indicator state for all CCs.

9. The method according to claim 8, wherein The instruction is provided in the received information (52).

10. The method according to claim 9, wherein, The received information indicates that the common downlink transmission configuration indicator state is quasi-co-location (QCL).

11. The method according to claim 8, wherein, The step of obtaining the instruction includes: Sending (614) to the base station a request to use a common downlink transmission configuration indicator state for all CCs; and Receiving (616) the instruction that identifies approval to use the common downlink transmission configuration indicator state.

12. The method according to any one of claims 8 to 11, wherein, The first CC and the second CC are obtained with the same common downlink transmission configuration indicator state.

13. A method for establishing communication with a user equipment (UE) (1) using inter-band carrier aggregation (CA) in a base station (110) of a radio network (100), the method comprising the steps of: Obtaining (710) information identifying the UE's ability to perform beam management for multiple component carriers (CCs); Sending (712) to the UE information (52) based on the ability, wherein the information indicates the co-location characteristics of a first CC in a first frequency band and a second CC in a second frequency band; Establishing (718) communication on the first CC and the second CC.

14. The method according to claim 13, wherein, The information indicating the co-location characteristic is sent based on the ability that identifies the affirmative ability to perform independent beam management on the first frequency band and the second frequency band.

15. The method according to claim 14, wherein, The information indicating the co-location characteristic is sent based on the ability that indicates the affirmative ability to perform independent beam management within a common spherical region on the first frequency band and the second frequency band.

16. The method according to claim 13, wherein, The information indicating the co-location characteristic is sent based on the ability that indicates the affirmative ability to perform aligned non-independent beam management on the first frequency band and the second frequency band.

17. The method according to any one of claims 13 to 16, wherein, The sent information indicates the co-location of the first transmission point TRP of the first CC and the second TRP of the second CC.

18. The method according to any one of claims 13 to 16, the method comprising the steps of: Providing (713) an instruction to the UE to use a common downlink transmission configuration indicator state for all CCs.

19. The method according to claim 18, wherein, The instruction is provided in the sent information (52).

20. The method according to claim 19, wherein, The sent information indicates that the common downlink transmission configuration indicator state is quasi-co-location QCL.

21. The method according to claim 18, wherein The step of providing the instruction includes: Receiving (714) from the UE a request to use a common downlink transmission configuration indicator state for all CCs; and Sending (716) the instruction that identifies approval to use the common downlink transmission configuration indicator state.

22. A user equipment UE (1), the UE being configured to establish communication with a wireless network (100) using inter-band carrier aggregation CA, the user equipment UE comprising: Logic (310), the logic being configured to control the UE to perform the following operations: Sending (610) to the wireless network information (51) that identifies the ability of the UE to perform beam management of multi-component carriers CC; Receiving (612) from a base station (110) of the wireless network information (52) indicating the co-location characteristic of a first CC in a first frequency band and a second CC in a second frequency band according to the sent ability; Establishing (617) communication between the UE (1) and the wireless network (100) using the first CC and the second CC.

23. The UE according to claim 22, wherein, The logic is configured to control the UE to perform the steps in the method according to any one of claims 2 to 12.

24. A base station (110) of a wireless network (100), the base station being configured to establish communication with a user equipment UE (1) using inter-band carrier aggregation CA, the base station comprising: Logic (410), the logic being configured to control the base station to perform the following operations: Obtaining (710) information that identifies the ability of the UE to perform beam management of multi-component carriers CC; Sending (712) to the UE information (52) according to the ability, wherein the information indicates the co-location characteristic of a first CC in a first frequency band and a second CC in a second frequency band; Establishing (718) communication on the first CC and the second CC.

25. The base station according to claim 24, wherein, The logic is configured to control the base station to perform the steps in the method according to any one of claims 14 to 21.

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