Method for beam alignment

Abstract

A method comprising: decoding, by a user equipment (UE), in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determining if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determining if the static transmission part is configured to toggle between two or more wide horizontal beams; configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measuring power level values of the first toggled transmission SSB signals using said at least one static beam; deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference

Description

METHOD FOR BEAM ALIGNMENTTECHNICAL FIELD

[0001] The present invention relates to beam alignment procedure.BACKGROUND

[0002] When a user equipment (UE) is in RRC Connected mode, it must periodically perform beam management related operations, such as tracking reference signal / channel state information reference signals (TRS / CSI-RS) measurements, synchronization signal blocks (SSB) measurements, as well as to report periodically the result of these measurements to the network.

[0003] The maximum number of Synchronization Signal Block (SSB) beams within an SSB burst for a specified carrier frequency in 5G is max 8 SSBs for frequencies below 6 GHz (FR1) and 64 SSBs frequencies above 6 GHz, but practically designed for FR2 (24.2- 52.6 GHz). The upcoming 6G standard will include new frequency ranges compared to 5G, including 4.4 - 4.8 GHz, 7.125 - 8.4 GHz and 14.8 - 15.35 GHz. These new bands above 6GHz might need more than 8 SSB beams within an SSB Burst, but not as many as 64 as currently specified.

[0004] The maximum number of SSB beams within an SSB burst will have to be redefined for 6G to include the new frequency ranges and to account for larger antenna apertures at the gNBs. Regardless of the final decision of the maximum number of SSB beams within an SSB burst for different frequency ranges, the potential increase of the allowed maximum number of SSB beams within an SSB burst for higher frequency ranges will also require the beam alignment procedure for frequency ranges to be re-configured with an increased and high number of SSBs. In addition, a higher number of SSBs will also increase the power consumption at the gNB.SUMMARY

[0005] Now, an improved method and technical equipment implementing the method has been invented, by which the above problems are alleviated. Various aspects include a method, an apparatus and a non-transitory computer readable medium comprising acomputer program, or a signal stored therein, which are characterized by what is stated in the independent claims. Various details of the embodiments are disclosed in the dependent claims and in the corresponding images and description.

[0006] The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0007] According to a first aspect, there is provided an apparatus comprising means for decoding, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; means for determining if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; means for determining if the static transmission part is configured to toggle between two or more wide horizontal beams; means for configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; means for measuring power level values of the first toggled transmission SSB signals using said at least one static beam; means for deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and means for normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0008] According to an embodiment, the apparatus comprises an analog antenna array or antenna panel.

[0009] According to an embodiment, the apparatus comprises means for determining the beam ensuring optimal power transfer for the current channel conditions; and configuring said beam for random access preamble transmission.

[0010] According to an embodiment, the apparatus comprises means for configuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, different analog beams for the rest of the received SSB signals; and means for measuring the power level value for each configured beam.

[0011] According to an embodiment, the apparatus comprises means for determining the best analog beam for communication with a network node based on the rest of the received SSB signals.

[0012] According to an embodiment, the apparatus comprises two or more antenna elements configured for digital pre-coding.

[0013] According to an embodiment, the apparatus comprises means for measuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, the power level values on each antenna element for each of the rest of the received SSB signals.

[0014] According to an embodiment, the apparatus comprises means for determining a best digital precoding for receiving the SSBs based on the rest of the received SSB signals.

[0015] An apparatus according to a second aspect comprises at least one processor and at least one memory, said at least one memory stored with computer program code thereon, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: decode, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determine if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determine if the static transmission part is configured to toggle between two or more wide horizontal beams; configure, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measure power level values of the first toggled transmission SSB signals using said at least one static beam; derive Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalize, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0016] A method according to a third aspect comprises decoding, by a user equipment (UE) in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determining if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determining if the static transmission part is configured to togglebetween two or more wide horizontal beams; configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measuring power level values of the first toggled transmission SSB signals using said at least one static beam; deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0017] Computer readable storage media according to further aspects comprise code for use by an apparatus, which when executed by a processor, causes the apparatus to perform the above methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more complete understanding of the example embodiments, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

[0019] Fig. 1 shows a schematic block diagram of an apparatus for incorporating a system information acquisition according to the embodiments;

[0020] Fig. 2 shows schematically a layout of an apparatus according to an example embodiment;

[0021] Fig. 3 shows a part of an exemplifying radio access network;

[0022] Fig. 4 shows examples of the 4-step CBRA procedure and the 2-step CBRA procedure;

[0023] Fig. 5 shows an example of a contemporary beam alignment procedure specified for 5G;

[0024] Fig. 6 shows an example of grid of beam (GoB) pattern comprising narrow beams with high additional antenna gain and a wide beam with a lower additional antenna gain;

[0025] Fig. 7 shows a flow chart for beam alignment procedure according to an embodiment;

[0026] Fig. 8 shows an example of a beam alignment procedure underlying the beam alignment procedure according to the embodiments; and

[0027] Fig. 9 shows a flow chart for beam alignment procedure according to an embodiment.DETAILED DESCRIPTON OF SOME EXAMPLE EMBODIMENTS

[0028] The following describes in further detail suitable apparatus and possible mechanisms carrying out the system information acquisition. While the following focuses on 5G networks, the embodiments as described further below are by no means limited to be implemented in said networks only, but they are applicable in any network supporting system information acquisition, especially 6G and any future generation networks.

[0029] In this regard, reference is first made to Figures 1 and 2, where Figure 1 shows a schematic block diagram of an exemplary apparatus or electronic device 50, which may incorporate the arrangement according to the embodiments. Figure 2 shows a layout of an apparatus according to an example embodiment. The elements of Figs. 1 and 2 will be explained next.

[0030] The electronic device 50 may for example be a mobile terminal or user equipment of a wireless communication system. The apparatus 50 may comprise a housing 30 for incorporating and protecting the device. The apparatus 50 further may comprise a display 32 and a keypad 34. Instead of the keypad, the user interface may be implemented as a virtual keyboard or data entry system as part of a touch-sensitive display.

[0031] The apparatus may comprise a microphone 36 or any suitable audio input which may be a digital or analogue signal input. The apparatus 50 may further comprise an audio output device, such as anyone of: an earpiece 38, speaker, or an analogue audio or digital audio output connection. The apparatus 50 may also comprise a battery 40 (or the device may be powered by any suitable mobile energy device such as solar cell, fuel cell or clockwork generator). The apparatus may further comprise a camera 42 capable of recording or capturing images and / or video. The apparatus 50 may further comprise an infrared port 41 for short range line of sight communication to other devices. In other embodiments the apparatus 50 may further comprise any suitable short-range communication solution such as for example a Bluetooth wireless connection or a USB / firewire wired connection.

[0032] The apparatus 50 may comprise a controller 56 or processor for controlling the apparatus 50. The controller 56 may be connected to memory 58 which may store both user data and instructions for implementation on the controller 56. The memory may be random access memory (RAM) and / or read only memory (ROM). The memory may store computer-readable, computer-executable software including instructions that, when executed, cause the controller / processor to perform various functions described herein. In some cases, the software may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The controller 56 may further be connected to codec circuitry 54 suitable for carrying out coding and decoding of audio and / or video data or assisting in coding and decoding carried out by the controller.

[0033] The apparatus 50 may comprise radio interface circuitry 52 connected to the controller and suitable for generating wireless communication signals for example for communication with a cellular communications network, a wireless communications system or a wireless local area network. The apparatus 50 may further comprise an antenna 44 connected to the radio interface circuitry 52 for transmitting radio frequency signals generated at the radio interface circuitry 52 to other apparatus(es) and for receiving radio frequency signals from other apparatus(es).

[0034] In the following, different exemplifying embodiments will be described using, as an example of an access architecture to which the embodiments may be applied, a radio access architecture based on Long Term Evolution Advanced (LTE Advanced, LTE-A) or new radio (NR, 5G), without restricting the embodiments to such an architecture, however. A person skilled in the art appreciates that the embodiments may also be applied to other kinds of communications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems are the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, the same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, sensornetworks, mobile ad-hoc networks (MANETs) and Internet protocol multimedia subsystems (IMS) or any combination thereof.

[0035] Figure 3 depicts examples of simplified system architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in Figure 3 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in Figure 3. The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

[0036] The example of Figure 3 shows a part of an exemplifying radio access network.

[0037] Figure 3 shows user devices 300 and 302 configured to be in a wireless connection on one or more communication channels in a cell with an access node (such as (e / g)NodeB) 304 providing the cell. The physical link from a user device to a (e / g)NodeB is called uplink or reverse link and the physical link from the (e / g)NodeB to the user device is called downlink or forward link. It should be appreciated that (e / g)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

[0038] A communication system typically comprises more than one (e / g)NodeB in which case the (e / g)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signaling purposes. The (e / g)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The (e / g)NodeB includes or is coupled to transceivers. From the transceivers of the (e / g)NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (e / g)NodeB is further connected to core network 310 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providingconnectivity of user devices (UEs) to external packet data networks, or mobile management entity (MME), etc. The CN may comprise network entities or nodes that may be referred to management entities. Examples of the network entities comprise at least an Access and Mobility Management Function (AMF).

[0039] The user device (also called a user equipment (UE), a user terminal, a terminal device, a wireless device, a mobile station (MS) etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a user device may be implemented with a corresponding network apparatus, such as a relay node, an eNB, and an gNB. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station.

[0040] The user device typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and / or touch screen computer, tablet, game console, notebook, and multimedia device. It should be appreciated that a user device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A user device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.Accordingly, the user device may be an loT-device. The user device may also utilize cloud. In some applications, a user device may comprise a small portable device with radio parts (such as a watch, earphones or eyeglasses) and the computation is carried out in the cloud. The user device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities. The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal or user equipment (UE) just to mention but a few names or apparatuses.

[0041] Various techniques described herein may also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts ofinterconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyberphysical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals.

[0042] Additionally, although the apparatuses have been depicted as single entities, different units, processors and / or memory units (not all shown in Fig. 1) may be implemented.

[0043] 5G enables using multiple input - multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and / or spectrum available. The access nodes of the radio network form transmission / reception (TX / Rx) points (TRPs), and the UEs are expected to access networks of at least partly overlapping multi-TRPs, such as macro-cells, small cells, pico-cells, femto-cells, remote radio heads, relay nodes, etc. The access nodes may be provided with Massive MIMO antennas, i.e. very large antenna array consisting of e.g. hundreds of antenna elements, implemented in a single antenna panel or in a plurality of antenna panels, capable of using a plurality of simultaneous radio beams for communication with the UE. The UEs may be provided with MIMO antennas having an antenna array consisting of e.g. dozens of antenna elements, implemented in a single antenna panel or in a plurality of antenna panels. Thus, the UE may access one TRP using one beam, one TRP using a plurality of beams, a plurality of TRPs using one (common) beam or a plurality of TRPs using a plurality of beams.

[0044] The 4G / LTE networks support some multi-TRP schemes, but in 5G NR the multi-TRP features are enhanced e.g. via transmission of multiple control signals via multi- TRPs, which enables to improve link diversity gain. Moreover, high carrier frequencies (e.g., mmWaves) together with the Massive MIMO antennas require new beam management procedures for multi-TRP technology.

[0045] 5G mobile communications supports a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications (such as (massive) machine-typecommunications (mMTC), including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and also capable of being integrated with existing legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, at least in the early phase, as a system, where macro coverage is provided by the LTE and 5G radio interface access comes from small cells by aggregation to the LTE. In other words, 5G is planned to support both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz - cmWave, below 6GHz - cmWave - mmWave). One of the concepts considered to be used in 5G networks is network slicing in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0046] Frequency bands for 5G NR are separated into two frequency ranges: Frequency Range 1 (FR1) including sub-6 GHz frequency bands, i.e. bands traditionally used by previous standards, but also new bands extended to cover potential new spectrum offerings from 410 MHz to 7125 MHz, and Frequency Range 2 (FR2) including frequency bands from 24.25 GHz to 52.6 GHz. Thus, FR2 includes the bands in the mmWave range, which due to their shorter range and higher available bandwidth require somewhat different approach in radio resource management compared to bands in the FR1.

[0047] The architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G require to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud / fog computing and grid / mesh computing, dew computing, mobile edge computing,cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

[0048] The communication system is also able to communicate with other networks, such as a public switched telephone network or the Internet 312, or utilize services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in Fig. 3 by “cloud” 314). The communication system may also comprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

[0049] Edge cloud may be brought into radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at the RAN side (in a distributed unit, DU) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 308).

[0050] It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be nonexistent. Some other technology advancements probably to be used are Big Data and all-IP, which may change the way networks are being constructed and managed. 5G (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be applied in 4G networks as well. The gNB is a next generation Node B (or, new Node B) supporting the 5G network (i.e., the NR).

[0051] 5G may also utilize non-terrestrial nodes 306, e.g. access nodes, to enhance or complement the coverage of 5G service, for example by providing backhauling, wireless access to wireless devices, service continuity for machine-to-machine (M2M) communication, service continuity for Internet of Things (loT) devices, service continuityfor passengers on board of vehicles, ensuring service availability for critical communications and / or ensuring service availability for future railway / maritime / aeronautical communications. The non-terrestrial nodes may have fixed positions with respect to the Earth surface or the non-terrestrial nodes may be mobile nonterrestrial nodes that may move with respect to the Earth surface. The non-terrestrial nodes may comprise satellites and / or HAPSs. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay node 304 or by a gNB located on-ground or in a satellite.

[0052] A person skilled in the art appreciates that the depicted system is only an example of a part of a radio access system and in practice, the system may comprise a plurality of (e / g)NodeBs, the user device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (e / g)NodeBs or may be a Home(e / g)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e / g)NodeBs of Fig. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. Typically, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e / g)NodeBs are required to provide such a network structure.

[0053] For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” (e / g)NodeBs has been introduced. Typically, a network which is able to use “plug-and-play” (e / g)Node Bs, includes, in addition to Home (e / g)NodeBs (H(e / g)nodeBs), a home node B gateway, or HNB-GW (not shown in Fig. 1). A HNB Gateway (HNB-GW), which is typically installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network.

[0054] The Radio Resource Control (RRC) protocol is used in various wireless communication systems for defining the air interface between the UE and a base station, such as eNB / gNB. This protocol is specified by 3GPP in in TS 36.331 for LTE and in TS 38.331 for 5G. In terms of the RRC, the UE may operate in LTE and in 5G in an idle mode or in a connected mode, wherein the radio resources available for the UE are dependent on the mode where the UE at present resides. In 5G, the UE may also operate in inactive mode. In the RRC idle mode, the UE has no connection for communication, but the UE is able to listen to page messages. In the RRC connected mode, the UE may operate in different states, such as CELL DCH (Dedicated Channel), CELL FACH (Forward Access Channel), CELL PCH (Cell Paging Channel) and URA PCH (URA Paging Channel). The UE may communicate with the eNB / gNB via various logical channels like Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Dedicated Control Channel (DCCH), Dedicated Traffic Channel (DTCH).

[0055] The transitions between the states is controlled by a state machine of the RRC. When the UE is powered up, it is in a disconnected mode / idle mode. The UE may transit to RRC connected mode with an initial attach or with a connection establishment. If there is no activity from the UE for a short time, eNB / gNB may suspend its session by moving to RRC Inactive and can resume its session by moving to RRC connected mode. The UE can move to the RRC idle mode from the RRC connected mode or from the RRC inactive mode.

[0056] The actual user and control data from network to the UEs is transmitted via downlink physical channels, which in 5G include Physical downlink control channel (PDCCH) which carries the necessary downlink control information (DCI), Physical Downlink Shared Channel (PDSCH), which carries the user data and system information for user, and Physical broadcast channel (PBCH), which carries the necessary system information to enable a UE to access the 5G network.

[0057] The user and control data from UE to the network is transmitted via uplink physical channels, which in 5G include Physical Uplink Control Channel (PUCCH), which is used for uplink control information including HARQ feedback acknowledgments, scheduling request, and downlink channel-state information for link adaptation, Physical Uplink Shared Channel (PUSCH), which is used for uplink data transmission, and PhysicalRandom Access Channel (PRACH), which is used by the UE to request connection setup referred to as random access.

[0058] The classical random access (RA) procedure is composed of multiple steps between UE and gNB for the UE to acquire uplink (UL) synchronization and obtain resources for the following up communication. The random access procedure has multiple purposes, but the main purposes would be to either (a) make the gNB aware that the UE is in need of establishing connection, or (b) provide a signal from the UE to the gNB that allows the gNB to adjust / correct the UE’s transmit timing.

[0059] The random access (RA) procedure may be carried out as network configured contention-free random access (CFRA) or contention-based random access (CBRA). The legacy CBRA procedure adopted from 4G / LTE to the 5G is called a 4-step RA procedure comprising four messages (Msgl, Msg2, Msg3 and Msg4).

[0060] In 4-step RA type CBRA, shown in Figure 4, the UE randomly selects an RA preamble from a pool of preambles shared with other UEs in the cell and transmits the RA preamble to an access node, such as to gNB, as Msgl. The gNB provides a random-access response (RAR) known as Msg2, wherein the RAR comprises the uplink (UL) time / frequency resources the UE should use for its UL transmission. If multiple UEs transmit preambles in the same frequency and time resource selecting the same preamble sequence, all those UEs decode the same RA response content and transmit PUSCH on the same UL time / frequency resources, knowns as Msg3. The network resolves the contention and the contention resolution sent by the gNB is known as Msg4.

[0061] In CFRA, the UE uses a dedicated preamble provided by the network specifically to said UE via RRC signaling or PDCCH order (e.g. MsgO). The RA preamble transmission from the UE to an access node, such as to gNB, is known as Msgl. The gNB then provides the random-access response (RAR) known as Msg2, whose reception completes the procedure. Thus, even though 4-step RA type CFRA procedure does not necessarily comprise fours steps, both CFRA and CBRA procedures are considered the same RA type (i.e. 4-step RA type).

[0062] For reducing the latency involved in 4-step RA procedure, a 2-step CBRA procedure has been introduced, shown in Figure 4. Therein, the RA preamble transmission on the PRACH (MsgA preamble corresponding to Msgl) and PUSCH (MsgA PUSCHcorresponding to Msg3) are transmitted together, and this is called MsgA. It is noted that while the Msg A preamble and Msg A PUSCH are indicated in separate steps in Figure 4, they can be transmitted in one step as well. As a response, UE may receive in so called MsgB an RAR acknowledging only the reception of the preamble (fallback to 4-step procedure) or containing also UE identity for contention resolution.

[0063] In 2-step CFRA procedure too, MsgA includes a preamble transmission on PRACH and a payload transmission on PUSCH. The UE then monitors for a response from the network within a configured window. Upon receiving the network response (RAR) known as MsgB, the UE ends the RA procedure or falls back to 4-step procedure depending on the content of MsgB. If the RA procedure with 2-step RA type is not completed after a number of MsgA transmissions, the UE can be configured to switch to CBRA with 4-step RA type.

[0064] In 3 GPP, the 4-step RA procedure is referred to as 4-step RA type or Type-1 RA procedure and the 2-step RA procedure as 2-step RA type or Type-2 RA procedure.

[0065] According to the present 5G NR specifications, the network configures random access resources in a semi-statically manner through a broadcast via system information block (SIB) or using UE-dedicated RRC configuration.

[0066] The transitions between the states are controlled by a state machine of the RRC. When the UE is powered up, it is in a Disconnected mode / Idle mode. The UE may transit to RRC Connected mode with an initial attach or with a connection establishment. If there is no activity from the UE for a short time, eNB / gNB may suspend its session by moving to RRC Inactive mode and can resume its session by moving to RRC Connected mode.The UE can move to the RRC Idle mode from the RRC Connected mode or from the RRC Inactive mode.

[0067] When the UE is in RRC Connected mode, it must periodically perform beam management related operations, such as tracking reference signal / channel state information reference signals (TRS / CSI-RS) measurements, synchronization signal blocks (SSB) measurements, as well as to report periodically the result of these measurements to the network.

[0068] When the UE is in RRC Idle / Inactive mode and it is controlled to transfer to RRC Connected mode, it must acquire System Information (SI) to access the network. TheSystem information (SI) for UEs comprises the Master Information Block (MIB) and a set of System Information Blocks (SIBs). The MIB comprises the basic system information and it is broadcast on PBCH periodically. The SIBs, in turn, comprise various scheduling and cell access information broadcast on PDSCH.

[0069] The beam alignment procedure, as specified for 5G (3GPP TR 38.802 section 6.1.6 and in TS 38.214 section 5.2), is illustrated in Fig. 5 for an example scenario, where the gNB is using 32 beams (506) for the SSB burst configured on a 16 x 16 element antenna array. The gNB may support a higher number of configured antenna elements for data communication, depending on the total size of the antenna array and the configured beams used in the channel state information (CSI) refinement phase (phase#2) (530). A higher number of used SSB beams within a SSB burst is also possible.

[0070] In the example of Fig. 5, beam alignment at the UE is depicted for both digital and analog implementation. Digital beam alignment represents the typical sub6GHz UE antenna implementation, where each single antenna may be connected to an RF branch and may receive simultaneously on all antennas supporting a specific frequency band. Some UE may also be capable of transmitting simultaneously on all antennas, while others may only transmit simultaneously on a reduced set of available antennas. Analog beam alignment represents the typical antenna array implementation for FR2 frequencies at the UE. Each antenna array may support two orthogonal polarizations connected to separate RF branches that may receive an independent signal on each polarization at the same time, or transmit a common signal combined on both polarizations. However, the UE may only configure two similar beams for receiving, or one beam for transmitting at any given time, and may have to configure multiple different beams to cover the angular domain of the antenna array.

[0071] The digital beam alignment at the UE represents FR1 frequencies where the UE in the RACH phase is expected to select the best antenna out of all possible antennas (no Phase#3) (532). Digital beam alignment is used for FR1 frequencies for multiple input multiple output (MiMo) by sending the same digital pre-code data on more than one antenna.

[0072] The analog beam alignment phase is for FR2 frequencies where the UE is expected to perform its analog beam alignment (540) after the RACH procedure (512).

[0073] During synchronization, the gNB may sweep 32 SSB beams in each SSB burst (506, 508) in a 1-15-16 grid of beam (GoB) pattern as shown in Fig. 6, where the narrow beams 1-31 (610) comprise high additional antenna gain (+24 dB), and the wide beam 32 (620) comprises a lower additional antenna gain (+ 9 dB).

[0074] In analog beam alignment, at 504 the UE may use a static Rx beam to monitor for the SSB beams transmitted by the gNB. In digital beam alignment, at 502 the UE may use up to four simultaneous Rx beams to monitor for the SSB beams transmitted by the gNB. In analog beam alignment and digital beam alignment, the UE may determine a best beam based on the monitoring. A UE will typically need to average 2 to 6 measurements of the SSB beams to counter effect fast fading in the channel, which means the UE will have to wait for 2 to 6 full SSB bursts before it can determine the best SSB beam for transmitting the preamble (msgl) (514) at the specified RACH occasion (RO). The default periodicity for SSB bursts in 5 G is 20 ms, which will result in a time consuming averaging processing time, especially for initial access or when the UE has utilized power save functions and have to reestablish an RRC connection.

[0075] In the example of Fig. 5, during Phase#l of the random access channel (RACH) procedure, the UE may send a preamble (Msgl) (514), as defined by master information block (MIB) and / or system information block (SIB) information, for the chosen best SSB beam, whereafter it may receive a Msg2 (516), transmit a Msg3 (518) and finally receive a msg4 (220) (4-step RACH). In digital beam alignment, the UE (510) may use a single static Tx / Rx beam during RACH. In analog beam alignment, the UE (512) may use a static Tx / Rx beam during RACH. In the example of Fig. 5, the gNB (522) may use a 32 x RO sweeps to monitor for Msgl (514), and may use a static Tx / Rx beam to monitor for Msg3 (518).

[0076] During Phase#2, CSI refinement may or may not be needed, depending on the gNB implementation, but CSI-RS (528) may still be needed for channel characterization. In digital beam alignment, the UE (524) may use a single static Tx / Rx beam to monitor for CSI-RS from the gNB. In analog beam alignment, the UE (526) may use a static Rx beam to monitor for CSI-RS from the gNB. The gNB may use a static Tx beam (530) to transmit the CSI-RS.

[0077] During Phase #3 or UE beam alignment, CSI-RS with repetition set to “ON” may be required for enabling the UE to perform beam alignment, and the number of CSI- RSs (536) for this phase may depend on the antenna array implementation at the UE. In analog beam alignment, the UE may use Rx sweeps (534) to monitor for the CSI-RS. The gNB may use a single Tx beam (538) to transmit the CSI-RS.

[0078] Once the UE beam (540) and the gNB beam (544) are aligned, data may be transmitted (542) from the UE to the gNB.

[0079] One disadvantage of this beam alignment procedure is that it is based on Tx sweeping, which is power consuming and requires feedback from the UE (msgl or UCI), for the gNB to select its best beam. In addition, due to the Tx sweeping it’s very difficult for the UE to use the different SSB beams for reliable UE beam alignment, and a specific phase#3 for UE beam alignment is added after the gNB beam alignment. This means that potential antenna gain at the UE is not utilized in the synchronization and RACH phases of the beam alignment procedure.

[0080] The maximum number of SSB beams within an SSB burst for a specified carrier frequency in 5G is maximum of 8 SSBs for frequencies below 6 GHz (FR1) and maximum of 64 SSBs frequencies above 6 GHz, but practically designed for FR2 (24.2- 52.6 GHz). The upcoming 6G standard will include new frequency ranges compared to 5G, including 4.4 - 4.8 GHz, 7.125 - 8.4 GHz and 14.8 - 15.35 GHz. These new bands above 6GHz might need more than 8 SSB beams within an SSB Burst, but not as many as 64 as currently specified.

[0081] Therefore, the maximum number of SSB beams within an SSB burst will have to be redefined for 6G to include the new frequency ranges and to account for larger antenna apertures at the gNBs. Regardless of what the maximum number of SSB beams within an SSB burst for different frequency ranges will be, the potential increase of the allowed maximum number of SSB beams within an SSB burst for higher frequency ranges will also require the beam alignment procedure for frequency ranges to be re-configured with an increased and high number of SSBs. In addition, a higher number of SSBs will also increase the power consumption at the gNB.

[0082] In the following, an enhanced method for beam alignment will be described in more detail, in accordance with various embodiments.

[0083] The method, which is disclosed in flow chart of Figure 7 as reflecting the operation of a terminal apparatus, such as a user equipment (UE), wherein the method comprises decoding (700), by a user equipment (UE), in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determining (702) if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determining (704) if the static transmission part is configured to toggle between two or more wide horizontal beams; configuring (706), in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measuring (708) power level values of the first toggled transmission SSB signals using said at least one static beam; deriving (710) Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalizing (712), upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0084] Thus, a new beam alignment procedure for frequency bands requiring a high number of SSBs is used in connection with RACH procedure. Therein, the SSB burst interval is divided into a static Tx part (with no beam sweeping) and a dynamic Rx part (with beam sweeping), where the Rx part will act as the random access occasion (RO) part as defined in the current 5GRACH procedure. The specific Tx / Rx split of the SSB burst may be embedded into the MIB message or a SIB message. For the static Tx part of the SSB burst, the gNB is configured with static wide horizontal aligned beam(s), where it can toggle between two or more wide horizontal beams (in azimuth), wherein a second beam is configured with a broader angular coverage in elevation overlapping the narrower angular coverage in elevation of a first beam.

[0085] The UE examines whether the Tx / Rx split of the SSB burst is used. If yes, the UE examines whether the toggle between two or more wide horizontal beams is used in the static Tx part. If yes, the UE configures at least one static beam for the first toggled Tx SSB signals, and measures power level values of the first SSB signals using said static beam. In other words, the UE does not change the beam. The UE derives AGtog (i.e. the gNB EIRP difference between the toggled Tx beams). Upon UE beam alignment procedurefor the rest of the Tx SSB bursts, the measured power level values of the SSBs are normalized using AGtog.

[0086] According to an embodiment, the user equipment comprises an analog antenna array or antenna panel.

[0087] Thus, the UE may comprise antenna arrays / panels that depend on analog beam steering, wherein upon starting the RACH procedure, the UE listens for SSB signals with a wide beam pattern using antenna array / panel, or even a single antenna element in an array. If no SSB signal is detected, the UE changes to use another antenna array / panel, based on the beam steering implementation.

[0088] According to an embodiment, the method comprises determining the beam ensuring optimal power transfer for the current channel conditions; and configuring said beam for random access preamble transmission.

[0089] Thus, after the normalization, the UE determines the best analog beam (i.e. the beam ensuring optimal power transfer considering the current channel condition between the gNB and the UEs) for the received SSB signals and configures it for preamble (Msg#l) transmissions as indicated by the Tx / Rx split of the SSB burst and the total length of the SSB burst Using this configuration, the UE transmits N number of preamble signals in Msgl and remains waiting for Msg2 to continue the RACH procedure.

[0090] According to an embodiment, the beam alignment procedure for the rest of the transmission SSB bursts comprises configuring different analog beams for the rest of the received SSB signals; and measuring the power level value for each configured beam.

[0091] Thus, prior to the normalization, the UE uses the rest of the Tx SSB bursts for its own beam alignment procedure. In the case of analog antenna arrays / panels, the UE uses analog beam steering, whereupon only one angular beam can be configured at a time. The UE determines analog beams for the remaining received SSB signals and measures the reference signals received power (RSRP) value for each configured beam. This enables the normalization to be carried out over all configured beams.

[0092] According to an embodiment, the method comprises determining the best analog beam for communication with a network node based on the rest of the received SSB signals.

[0093] Thus, after configuring all analog beams and carrying out the normalization, the UE may determine the best analog beam for the received SSB signals. The best beam is then configured for preamble (Msg#l) transmissions as indicated by the Tx / Rx split of the SSB burst and the total length of the SSB burst.

[0094] According to an embodiment, the user equipment comprises two or more antenna elements configured for digital pre-coding.

[0095] Thus, the UE antenna implementation may comprise a plurality of individual antenna elements, which rely on digital combining, where digital pre-coding is utilized. Consequently, upon starting the RACH procedure, the UE configures one or more antenna elements and listens for SSB signals on all receiver chains without pre-coding.

[0096] According to an embodiment, the beam alignment procedure for the rest of the transmission SSB bursts comprises measuring the power level values on each antenna element for each of the rest of the received SSB signals.

[0097] Again, prior to the normalization and in the case of individual antenna elements utilizing digital pre-coding, the UE measures the reference signals received power (RSRP) value for all receiver chains of the supported individual antenna elements. The UE may then average the received RSRP values for each receiver chain. This enables the normalization to be carried out over all RSRP values for each receiver chain.

[0098] According to an embodiment, the method comprises determining a best digital precoding for receiving the SSBs based on the rest of the received SSB signals.

[0099] Thus, after configuring all the remaining received SSBs signals and carrying out the normalization, the UE may determine the best digital precoding for receiving the SSBs. In addition, if the UE is Rx-to-Tx calibrated and supports multi-layer UL, it may use the same digital pre-coding values for the preamble in Msgl.

[0100] In the above method and the related embodiments, an enhanced beam alignment procedure is utilized as an underlying procedure. This enhanced beam alignment procedure supports the higher granularity of configurable (narrower) beams expected for upcoming 6G gNBs due to the introduction of new higher frequency ranges and larger gNB antenna arrays.

[0101] In the enhanced beam alignment procedure, the SSB burst interval is divided into a static Tx part (no beam sweeping) and a dynamic Rx part (beam sweeping), wherethe Rx part will act as the RO part in the current 5G RACH procedure. The specific Tx / Rx split of the SSB burst will have to be embedded into the MIB message or a SIB message.

[0102] The gNB is configured with static wide horizontal aligned beam(s) in the Tx portion of the SSB burst, where it can toggle between two or more wide horizontal beams (in azimuth), wherein a second beam is configured with a broader angular coverage in elevation overlapping the narrower angular coverage in elevation of a first beam. The specific number of toggled beams will have to be embedded into the Master Block Information (MIB) message or a System Block Information (SIB) message.

[0103] The enhanced beam alignment procedure may be illustrated by an example shown in Figure 8, where the beam alignment at the UE is depicted for both digital and analog implementations.

[0104] In 6G, UE antenna implementation for frequencies below 10 GHz is expected to be single antennas, as described for the digital beam alignment, whereas antenna implementation for FR2 is expected to be antenna arrays as described for the analog beam alignment. However, antenna implementation for the new frequency band at 15 GHz may be either or both, as both concepts are viable implementations for a 6G UE. The embodiments of the present disclosure may be applicable to digital beam alignment and / or to analog beam alignment.

[0105] In the synchronization phase, the gNB may be configured to transmit 8 SSB signals (in this example) (806) with common wide horizontal beams and a narrow vertical beam (808). One or more addition wide horizontal beams may be included in this phase, for example for increased synchronization coverage in elevation if needed. In the case of a plurality of horizontal beams and a wider vertical beam, the gNB may toggle between these beams. The gNB may only need one wide horizontal beam to cover the full cell for synchronization. The wide horizontal beam, which is static, may be used instead of beam sweeping.

[0106] A single wide horizontal beam may cover most of the cell in the azimuth dimension, except the higher elevation beams. However, spreading the energy of one beam across the full horizontal / azimuth angle domain (120°) may reduce the antenna gain of that single beam by approximately 12 dB (e.g. for a 16x16 antenna array). This may be a 12 dB increase compared to using a single wide beam in both azimuth and elevation. Assuch, this approach may offer a good gain compromise for an increases gNB power efficiency during the SSB phase. In addition, this antenna gain loss may be acceptable for some of these new high frequency ranges, as they are intended to be used for high throughput data communication, which will require high SINK levels (up to 30 dB for the highest modulation and coding scheme (MCS), and maybe even higher SINK for potential new modulation formats defined for 6G).

[0107] In the example of Fig. 8, in the synchronization phase of analog beam alignment (804), the UE may use two wide beams and / or 6 analog sweeps to monitor for the SSB signals transmitted by the gNB. In the synchronization phase of digital beam alignment (802), the UE may use a plurality of sequential single Rx beam sweeps (antennas) to monitor for the SSB signals transmitted by the gNB, or use all Rx beams (antennas) simultaneously to obtain up to 6 dB Rx combining gain.

[0108] Since the UE may use the synchronization phase for beam alignment, it may utilize antenna gain for the RACH procedure and transmit msgl (814) and msg3 (818) with added gain. A UE implemented with digital beam alignment (810) and fully calibrated (e.g. reciprocal RF front end for Tx and Rx) may use UL None-Codebook-Based precoding based on the received SSB signals in the synchronization phase, as those signals were sent with static beams (no beam sweeping).

[0109] The second Rx portion of the SSB burst may be configured for RO where the UE may transmit one preamble (msgl) per allocated SSB burst (8 in this example) (814). The preamble may be transmitted, during the Rx portion of the SSB burst, a number of times that is equal to or less than the number of SSB signals allocated for the Rx portion of the SSB burst. The preamble may be selected based on the best beam detected by the UE during the synchronization phase. It may be noted that while the number of preambles transmitted by the UE increases in this example embodiment as compared to Fig. 4, the UE does not transmit preambles very often; accordingly the resulting increase in resource use and UE energy consumption is not very high. The gNB may sweep between 8 vertical beams (810), as illustrated in Fig. 8, to determine an initial angular direction of the UE. These vertical beams may have full coverage in both the azimuth dimension (collectively) and the elevation dimension (individual), but with a 6 dB reduced antenna gain (+18dB vs. 24 dB) at the gNB compared to the currently used gNB beams during the RO procedure for5G. However, as the UE may have already aligned its beam in the synchronization phase, that 7 dB gain may be added here, increasing the total antenna gain by 1 dB for the RACH phase compared to 5G.

[0110] In the example of Fig. 8, in the RACH phase of digital beam alignment (810), the UE may use static pre-coded TX beam. In the RACH phase of analog beam alignment (812), the UE may use a best Rx beam. In the RACH phase, the UE may transmit Msgl (814) to the gNB. The gNB may receive the Msgl using, in this example, eight Rx SSB vertical beam sweeps (822). The gNB may transmit Msg2 (816) to the UE. The UE may transmit Msg3 (818) to the gNB. The gNB may receive Msg3 using, in this example, a static Tx / Rx SSB vertical beam (822). The gNB may transmit Msg4 (820) to the UE.

[0111] In an example embodiment, a standard CSI beam refinement phase may be included. During the CSI beam refinement phase, the gNB may select the best narrow beam for data after the UE is RRC connected, which may be performed based, at least partially, on the best vertical beam found during the Rx (RO) beam sweeping phase, shown in Fig. 8 at 822.

[0112] In an example embodiment, two information elements (IE), ssb-Tx / RxSplit and ssb-TxToggle, may be added into, for example, the SIB1 message (ServingCellConfigCommon or ServingCellConfigCommonSIB), assuming this format is reused for 6G. An example of these IE in ServingCellConfigCommon may be:ServingCellConfigCommon ::= SEQUENCE { ssb-PositionsInBurst CHOICE { shortBitmap BIT STRING (SIZE (4)), mediumBitmap BIT STRING (SIZE (8)), longBitmap BIT STRING (SIZE (64)) OPTIONAL, - Cond AbsFreqSSB ssb-periodicityServingCell ENUMERATED { ms5, ms 10, ms20. ms40, ms80, msl60, spare2, sparel }OPTIONAL, - Need S ssb-Tx / RxSplit BIT STRING (SIZE (2)) ssb-TxToggle BIT STRING (SIZE (l))

[0113] In an example embodiment, the interpretation of the two-BIT allocation for the ssb-Tx / RxSplit IE may be as follows. Where ssb-Tx / RxSplit = 00, the first 4 SSB signals may be used for Tx. Where ssb-Tx / RxSplit = 01, the first 8 SSB signals may be used for Tx. Where ssb-Tx / RxSplit = 10, the first 16 SSB signals may be used for Tx. Where ssb- Tx / RxSplit = 11, the first 32 SSB signals may be used for Tx. The remaining SSB allocations may be used for RO. It may be noted that ssb-Tx / RxSplit is not limited to two bits; a higher number of bits may be assigned to the ssb-Tx / RxSplit IE for higher granularity of the Tx / Rx split, or different values of SSBs for Tx than what is exemplified here.

[0114] In an example embodiment, the gNB may be configured to use multiple horizontal beams, or may be configured to use only one horizontal beam. The configuration of the gNB may, for example, be based on the environment in which the gNB operates. For example, if the geography is flat and / or there are few tall buildings, toggling between wide horizontal beams with different elevations may be unnecessary. In contrast, in a city or a mountainous area, full(er) coverage in the elevation dimension may be useful, such that the gNB may be configured to toggle between wide horizontal beams during the synchronization phase.

[0115] The interpretation of the one-BIT allocation for the ssb-TxToggle IE may be as follows. Where ssb-TxToggle = 0, only one horizontal beam may be used, and no toggling may be performed. Where ssb-TxToggle = 1, there may be two horizontal toggled beams. It may be noted that ssb-TxToggle is not limited to one bit; a higher number of bits may be assigned to the ssb-Tx / RxSplit IE for a higher number of toggled horizontal beams in the Tx phase of the SSB burst than what is exemplified here.

[0116] If both IES (i.e. ssb-Tx / RxSplit and ssb-TxToggle) are not included in the SIB1 message (e.g. neither is included) or “VOID”, it may be indicated that the gNB is using a legacy 5G beam alignment procedure.

[0117] The above method and the related embodiments are further illustrated by the flow chart of Figure 9. It is noted that the flow chart includes options for both digital and analog implementations, as described more in detail below.

[0118] The process starts by the UE initiating (900) the RACH procedure. For analog implementation, the UE configures (902a) a first antenna array / panel with a wide beam and listens for SSB signals. Herein, only a single patch element in the antenna array may be configured, as well. The configuration may be a single polarization or both orthogonal polarizations simultaneously, if supported by the UE.

[0119] Alternatively for digital implementation, the UE configures (902b) one or more individual antenna elements and listens for SSB signals.

[0120] The UE determines (904) if it has received a SSB signal. If not, the analog implementation may involve checking (906), if the timer has expired. The timer threshold may be, for example, the default SSB burst periodicity of 20 ms or its multiplication. If the timer has expired, the UE may configure (908) a second antenna array / panel with a wide beam and continues listening for SSB signals (902a). If the timer has not expired, the UE continues listening for SSB signals using the first antenna array / panel (902a).

[0121] In the digital implementation, if it is noticed (904) that the UE has not yet received a SSB signal, the UE continues to listen (902b) for SSB signals with the one or more individual antenna elements.

[0122] When the SSB signals have been detected (904), the UE decodes (910) the MIB and the SIBs embedded in the SSB signals. Based on the MIB and / or SIBs, for example SIB1 as described above, the UE determines (912) if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping. Herein, the UE may evaluate the contents of ssb-Tx / RxSplit IE as described above. If no SSB Tx / Rx split is used, the UE reverts (914) to the conventional (legacy) 5G beam alignment procedure.

[0123] If SSB Tx / Rx split is in use, the UE determines (916) if the gNB is utilizing toggled beams for the transmission of SSB signals and if it does, how many beams it toggles. Herein, the UE may evaluate the contents of ssb-TxToggle IE as described above. The UE configures a static beam, for example the beam configuration used in decoding (910) the MIB and the SIBs embedded in the SSB signals, and measures (918) the power, such as the RSRP values, of the first SSB signals using that static beam. The number of needed SSB signals is equal to the value of ssb-TxToggle. The UE then derives (920) the SSB toggling gain difference AGtog (i.e. the EIRP difference between the toggledtransmission beams) based on the power measurements (918). If no toggled beams are used by the gNB (916), the steps 918 and 920 are skipped.

[0124] In the analog implementation, the UE configures (922a) different analog beams for the remaining received SSB signals and measures the RSRP value for each configured beam.

[0125] In the digital implementation, the UE measures (922b) the RSRP values on all supported individual antenna element for each of the remaining received SSB signals.

[0126] The UE then uses the derived SSB toggling gain difference AGtog to normalize (924) the measured RSRP values. If no toggled beams are used by the gNB (916), the normalization step is not needed.

[0127] In the analog implementation, the UE then uses all the remaining received SSBs signals to determine (926a) the best analog beam for communication with the gNB. The UE may require more than one SSB burst depending on the Layerl / 3 averaging and the number of received SSB signals within a SSB burst. Nevertheless, less transmitted SSBs from the gNB are required compared to the legacy beam alignment procedure defined for 5G, since herein all transmitted SSB signals can be used for Layerl / 3 averaging.

[0128] In the digital implementation, the UE uses all the remaining received SSBs signals to determine (926b) the best digital precoding for receiving the SSBs. In addition, if the UE is Rx-to-Tx calibrated and supports multi-layer UL, it can use the same digital precoding values for the preamble (msgl).

[0129] Finally, the UE transmits (928) x number of preamble signals (Msgl), wherein the number x is indicated by ssb-Tx / RxSplit and the total length of the SSB burst. Then UE remains for waiting (930) for Msg2 to continue the RACH procedure.

[0130] The methods and the related embodiments may provide various advantages. The methods and the related embodiments enable a beam alignment procedure for frequency ranges to be re-configured with reduced number of SSBs required from gNB. Moreover, faster beam alignment is enabled as all Layerl / 3 averaging at the UE can be performed within a single SSB burst using AGtog.

[0131] An apparatus, such as a UE, according to an aspect comprises means for decoding, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; means for determining if the SSB burstinterval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; means for determining if the static transmission part is configured to toggle between two or more wide horizontal beams; means for configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; means for measuring power level values of the first toggled transmission SSB signals using said at least one static beam; means for deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and means for normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0132] According to an embodiment, the apparatus comprises an analog antenna array or antenna panel.

[0133] According to an embodiment, the apparatus comprises means for determining the beam ensuring optimal power transfer for the current channel conditions; and configuring said beam for random access preamble transmission.

[0134] According to an embodiment, the apparatus comprises means for configuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, different analog beams for the rest of the received SSB signals; and means for measuring the power level value for each configured beam.

[0135] According to an embodiment, the apparatus comprises means for determining the best analog beam for communication with a network node based on the rest of the received SSB signals.

[0136] According to an embodiment, the apparatus comprises two or more antenna elements configured for digital pre-coding.

[0137] According to an embodiment, the apparatus comprises means for measuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, the power level values on each antenna element for each of the rest of the received SSB signals.

[0138] According to an embodiment, the apparatus comprises means for determining a best digital precoding for receiving the SSBs based on the rest of the received SSB signals.

[0139] An apparatus according to a further aspect comprises at least one processor and at least one memory, said at least one memory stored with computer program code thereon, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: decode, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determine if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determine if the static transmission part is configured to toggle between two or more wide horizontal beams; configure, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measure power level values of the first toggled transmission SSB signals using said at least one static beam; derive Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalize, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0140] According to an embodiment, the apparatus comprises an analog antenna array or antenna panel.

[0141] According to an embodiment, the apparatus comprises code configured to cause the apparatus to determine the beam ensuring optimal power transfer for the current channel conditions; and configure said beam for random access preamble transmission.

[0142] According to an embodiment, the apparatus comprises code configured to cause the apparatus to configure, upon the beam alignment procedure for the rest of the transmission SSB bursts, different analog beams for the rest of the received SSB signals; and measure the power level value for each configured beam.

[0143] According to an embodiment, the apparatus comprises code configured to cause the apparatus to determine the best analog beam for communication with a network node based on the rest of the received SSB signals.

[0144] According to an embodiment, the apparatus comprises two or more antenna elements configured for digital pre-coding.

[0145] According to an embodiment, the apparatus comprises code configured to cause the apparatus to measure, upon the beam alignment procedure for the rest of thetransmission SSB bursts, the power level values on each antenna element for each of the rest of the received SSB signals.

[0146] According to an embodiment, the apparatus comprises code configured to cause the apparatus to determine a best digital precoding for receiving the SSBs based on the rest of the received SSB signals.

[0147] A further aspect relates to a computer program product, stored on a non- transitory memory medium, comprising computer program code, which when executed by at least one processor, causes an apparatus at least to perform: decode, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determine if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determine if the static transmission part is configured to toggle between two or more wide horizontal beams; configure, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measure power level values of the first toggled transmission SSB signals using said at least one static beam; derive Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalize, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

[0148] Such apparatuses may comprise e.g. the functional units disclosed in any of the Figures 1- 3 for implementing the embodiments.

[0149] In general, the various embodiments of the invention may be implemented in hardware or special purpose circuits or any combination thereof. While various aspects of the invention may be illustrated and described as block diagrams or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0150] Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting alogic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0151] Programs, such as those provided by Synopsys, Inc. of Mountain View, California and Cadence Design, of San Jose, California automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or "fab" for fabrication.

[0152] The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended examples. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention.

Claims

CLAIMS1. An apparatus comprising: means for decoding, in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; means for determining if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; means for determining if the static transmission part is configured to toggle between two or more wide horizontal beams; means for configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; means for measuring power level values of the first toggled transmission SSB signals using said at least one static beam; means for deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and means for normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

2. The apparatus according to claim 1, comprising an analog antenna array or antenna panel.

3. The apparatus according to claim 2, comprising means for determining the beam ensuring optimal power transfer for the current channel conditions; and configuring said beam for random access preamble transmission.

4. The apparatus according to claim 2 or 3, comprising32means for configuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, different analog beams for the rest of the received SSB signals; and means for measuring the power level value for each configured beam.

5. The apparatus according to any of claims 2 - 4, comprising means for determining the best analog beam for communication with a network node based on the rest of the received SSB signals.

6. The apparatus according to claim 1, comprising two or more antenna elements configured for digital pre-coding.

7. The apparatus according to claim 6, comprising means for measuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, the power level values on each antenna element for each of the rest of the received SSB signals.

8. The apparatus according to claim 6 or 7, comprising means for determining a best digital precoding for receiving the SSBs based on the rest of the received SSB signals.

9. A method comprising: decoding, by a user equipment (UE), in connection with a random access (RACH) procedure, a configuration for the synchronization signal block (SSB) burst interval; determining if the SSB burst interval is divided into a static transmission part with no beam sweeping and a dynamic receiving part including beam sweeping, wherein the receiving part is used as random access occasion in the RACH procedure; determining if the static transmission part is configured to toggle between two or more wide horizontal beams;configuring, in response to the toggle being configured, at least one static beam for first toggled transmission SSB signals; measuring power level values of the first toggled transmission SSB signals using said at least one static beam; deriving Equivalent Isotropic Radiated Power (EIRP) difference between the toggled transmission beams; and normalizing, upon beam alignment procedure for the rest of the transmission SSB bursts, the measured power level values of the SSBs by the EIRP difference.

10. The method according to claim 1, wherein the user equipment (UE) comprises an analog antenna array or antenna panel, and the method comprises determining the beam ensuring optimal power transfer for the current channel conditions; and configuring said beam for random access preamble transmission.

11. The method according to claim 10, comprising configuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, different analog beams for the rest of the received SSB signals; and measuring the power level value for each configured beam.

12. The method according to claim 10 or 11, comprising determining the best analog beam for communication with a network node based on the rest of the received SSB signals.

13. The method according to claim 9, wherein the user equipment (UE) comprises two or more antenna elements configured for digital pre-coding, and the method comprises measuring, upon the beam alignment procedure for the rest of the transmission SSB bursts, the power level values on each antenna element for each of the rest of the received SSB signals.

14. The method according to claim 13, comprisingdetermining a best digital preceding for receiving the SSBs based on the rest of the received SSB signals.

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