Beam alignment

Abstract

A method includes transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna, and receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

Description

BEAM ALIGNMENTTECHNICAL FIELD

[0001] This description relates to wireless communications.BACKGROUND

[0002] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.

[0003] An example of a cellular communication system is an architecture that is being standardized by the 3rd Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. EUTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations or access points (APs), which are referred to as enhanced Node AP (eNBs), provide wireless access within a coverage area or cell. In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. Aspects of LTE are also continuing to improve.

[0004] 5G New Radio (NR) development is part of a continued mobile broadband evolution process to meet the requirements of 5G, similar to earlier evolution of 3G and 4G wireless networks. In addition, 5G is also targeted at the new emerging use cases in addition to mobile broadband. A goal of 5G is to provide significant improvement in wireless performance, which may include new levels of data rate, latency, reliability, and security. 5G NR may also scale to efficiently connect the massive Internet of Things (loT) and may offer new types of mission-critical services. For example, ultra-reliable and low-latency communications (URLLC) devices may require high reliability and very low latency. 6G and other networks are also being developed.SUMMARY

[0005] In some aspects, the techniques described herein relate to an apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: transmitting on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and receiving on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

[0006] In some aspects, the techniques described herein relate to an apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving on a first carrier from a user device, an indication ofsupport for second carrier beam alignment, wherein the indication includes information associated with an antenna; and transmitting on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.

[0007] In some aspects, the techniques described herein relate to a method including: transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

[0008] In some aspects, the techniques described herein relate to a method including: receiving, by a first network node on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and transmitting, by the first network node on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.

[0009] In some aspects, the techniques described herein relate to an apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: transmitting on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and receiving on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0010] In some aspects, the techniques described herein relate to an apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and transmitting on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0011] In some aspects, the techniques described herein relate to a method including: transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0012] In some aspects, the techniques described herein relate to a method including: receiving, by a first network node on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication includes information associated with an antenna; and transmitting, by the first network node on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0013] Other example embodiments are provided or described for each of the example methods, including: means for performing any of the example methods; a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform any of the example methods; and an apparatus including at least one processor, and at least one memory including computer program code, 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 any of the example methods.

[0014] The details of one or more examples of embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a block diagram of a wireless network.

[0016] FIG. 2 is a diagram illustrating an example FWA deployment scenario with a CPE mounted outdoor servicing multiple indoor devices.

[0017] FIG. 3 is a diagram illustrating a beam alignment procedure.

[0018] FIG. 4 is a diagram illustrating a grid of beam pattern for 32 SSBs.

[0019] FIG. 5 is a diagram illustrating an example FWA deployment scenario with different inter-site distance (ISD) for FR1 and FR2 gNBs.

[0020] FIG. 6 is diagram illustrating an example scenario with UE / CPE synchronization anchor in FR1 for configuration of FR2 beam alignment RACH.

[0021] FIG. 7 is a diagram illustrating an example LBB RACH beam alignment procedure for analog beam alignment.

[0022] FIG. 8 is a diagram illustrating an example full RACH beam alignment procedure for analog beam alignment.

[0023] FIG. 9 is a diagram illustrating a LBB RACH beam alignment procedure for digital beam alignment.

[0024] FIG. 10 is a diagram illustrating a full RACH beam alignment procedure for digital beam alignment.

[0025] FIG. 11 is a flow chart illustrating operation of an apparatus (e.g., which may be a UE or user device, or other apparatus) according to an example embodiment.

[0026] FIG. 12 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment.

[0027] FIG. 13 is a flow chart illustrating operation of an apparatus (e.g., which may be a UE or user device, or other apparatus) according to an example embodiment.

[0028] FIG. 14 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment.

[0029] FIG. 15 is a block diagram of a wireless station or node (e.g., UE, user device, AP, BS, eNB, gNB, RAN node, network node, TRP, or other node) 1300 according to an example embodiment.DETAILED DESCRIPTION

[0030] It shall be understood that although the terms "first,” "second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and / or” includes any and all combinations of one or more of the listed terms.

[0031] As used herein, unless stated explicitly, performing a step "in response to A” does not indicate that the step is performed immediately after "A” occurs and one or more intervening steps may be included.

[0032] FIG. 1 is a block diagram of a wireless network 130. In the wireless network 130 of FIG. 1, user devices 131, 132, 133 and 135, which may also be referred to as mobile stations (MSs) or user equipment (UEs), may be connected (and in communication) with a base station (BS) 134, which may also be referred to as an access point (AP), an enhanced Node B (eNB), a gNB or a network node. The terms user device and user equipment (UE) may be used interchangeably. A BS may also include or may be referred to as a RAN (radio access network) node, and may include a portion of a BS or a portion of a RAN node, such as e.g., such as a centralized unit (CU) and / or a distributed unit (DU) in the case of a split BS or split gNB. At least part of the functionalities of a BS (e.g., access point (AP), base station (BS) or (e)Node B (eNB), gNB, RAN node) may also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS (or AP) 134 provides wireless coverage within a cell 136, including to user devices (or UEs) 131, 132, 133 and 135. Although only four user devices (or UEs) are shown as being connected or attached to BS 134, any number of user devices may be provided. BS 134 is also connected to a core network 150 via a S1 interface 151 . This is merely one simple example of a wireless network, and others may be used.

[0033] A base station (e.g., such as BS 134) is an example of a radio access network (RAN) node within a wireless network. A BS (or a RAN node) may be or may include (or may alternatively be referred to as), e.g., an access point (AP), a gNB, an eNB, or portion thereof (such as a centralized unit (CU) and / or a distributed unit (DU) in the case of a split BS or split gNB), or other network node.

[0034] Some functionalities of the communication network may be carried out, at least partly, in a central / centralized unit, CU, (e.g., server, host or node) operationally coupled to distributed unit, DU, (e.g., a radio head / node). Thus, 5G networks architecture may be based on a so-called CU-DU split. The gNB-CU (central node) may control a plurality of spatially separated gNB-DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some embodiments, however, the gNB-DUs (also called DU) may comprise e.g., a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the gNB-CU (also called a CU) may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too.

[0035] According to an illustrative example, a BS node (e.g., BS, eNB, gNB, CU / DU, ...) or a radio access network (RAN) may be part of a mobile telecommunication system. A RAN (radio access network) may include one or more BSs or RAN nodes that implement a radio access technology, e.g., to allow one or more UEs to have access to a network or core network (CN). Thus, for example, the RAN (RAN nodes, such as BSs or gNBs) may reside between one or more user devices or UEs and a core network. According to an example embodiment, each RAN node (e.g., BS, eNB, gNB, CU / DU, ...) or BS may provide one or more wireless communication services for one or more UEs or user devices, e.g., to allow the UEs to have wireless access to a network, via the RAN node. Each RAN node or BS may perform or provide wireless communication services, e.g., such as allowing UEs or user devices to establish a wireless connection to the RAN node, and sending data to and / or receiving data from one or more of the UEs. For example, after establishing a connection to a UE, a RAN node or network node (e.g., BS, eNB, gNB, CU / DU, ...) may forward data to the UE that is received from a network or the core network, and / or forward data received from the UE to the network or core network. RAN nodes or network nodes (e.g., BS, eNB, gNB, CU / DU, ...) may perform a wide variety of other wireless functions or services, e.g., such as broadcasting control information (e.g., such as system information or on-demand system information) to UEs, paging UEs when there is data to be delivered to the UE, assisting in handover of a UE between cells, scheduling of resources for uplink data transmission from the UE(s) and downlink data transmission to UE(s), sending control information to configure one or more UEs, and the like. These are a few examples of one or more functions that a RAN node or BS may perform.

[0036] A user device or user node (user terminal, user equipment (UE), mobile terminal, handheld wireless device, etc.) may refer to a portable computing device that includes wireless mobile communication devices operating either with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (MS), a mobile phone, a cell phone, a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or measurement device, etc.), a laptop and / or touch screen computer, a tablet, a phablet, a game console, a notebook, a vehicle, a sensor, and a multimedia device, as examples, or any other wireless device. It should be appreciated that a user device may also be (or may include) a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. Also, a user node may include a user equipment (UE), a user device, a user terminal, a mobile terminal, a mobilestation, a mobile node, a subscriber device, a subscriber node, a subscriber terminal, or other user node. For example, a user node may be used for wireless communications with one or more network nodes (e.g., g N B, eNB, BS, AP, CU, DU, CU / DU) and / or with one or more other user nodes, regardless of the technology or radio access technology (RAT). In LTE (as an illustrative example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility / handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks. Other types of wireless networks, such as 5G (which may be referred to as New Radio (NR)) may also include a core network.

[0037] In addition, the techniques described herein may be applied to various types of user devices or data service types, or may apply to user devices that may have multiple applications running thereon that may be of different data service types. New Radio (5G) development may support a number of different applications or a number of different data service types, such as for example: machine type communications (MTC), enhanced machine type communication (eMTC), Internet of Things (loT), and / or narrowband loT user devices, enhanced mobile broadband (eMBB), and ultra-reliable and low-latency communications (URLLC). Many of these new 5G (NR) - related applications may require generally higher performance than previous wireless networks.

[0038] loT may refer to an ever-growing group of objects that may have Internet or network connectivity, so that these objects may send information to and receive information from other network devices. For example, many sensor type applications or devices may monitor a physical condition or a status and may send a report to a server or other network device, e.g., when an event occurs. Machine Type Communications (MTC, or Machine to Machine communications) may, for example, be characterized by fully automatic data generation, exchange, processing and actuation among intelligent machines, with or without intervention of humans. Enhanced mobile broadband (eMBB) may support much higher data rates than currently available in LTE.

[0039] Ultra-reliable and low-latency communications (URLLC) is a new data service type, or new usage scenario, which may be supported for New Radio (5G) systems. This enables emerging new applications and services, such as industrial automations, autonomous driving, vehicular safety, e-health services, and so on. 3GPP targets in providing connectivity with reliability corresponding to block error rate (BLER) of 10-5 and up to 1 ms U-Plane (user / data plane) latency, by way of illustrative example. Thus, for example, URLLC user devices / UEs may require a significantly lower block error rate than other types of user devices / UEs as well as low latency (with or without requirement for simultaneous high reliability). Thus, for example, a URLLC UE (or URLLC application on a UE) may require much shorter latency, as compared to an eMBB UE (or an eMBB application running on a UE).

[0040] The techniques described herein may be applied to a wide variety of wireless technologies or wireless networks, such as 5G (New Radio (NR)), cmWave, and / or mmWave band networks, loT, MTC, eMTC, eMBB, URLLC, 6G, etc., or any other wireless network or wireless technology. These example networks, technologies or data service types are provided only as illustrative examples.

[0041] A user device (or UE) may measure various signals and may transmit one or more measurement reports to the network. For example, a UE may measure reference signals received from one or more network nodes (e.g., gNBs or DUs), including channel state information-reference signals (CSI- RSs) and / or synchronization signal block (SSB) reference signals, demodulation references signals, and / or other reference signals. Based on received reference signals, the UE may measure various signal parameters, e.g., such as reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), received signal strength indicator (RSSI), or other signal parameter.

[0042] The PHY (physical) layer may refer to layer 1 (L1) and MAC (media access control) may refer to layer 2 (L2). RSRP, RSRQ, SINR and RSSI are signal quantities measured at layer 1 (L1). The UE may send L1 measurement reports (e.g., CSI-RS reports, which include measurements of one or more signal parameters for one or more cells) to a gNB, source DU or serving cell. These L1 measurement reports may be sent periodically, for example, or aperiodically. L1 / L2 measurement reports may include no averaging or filtering of measurement values or may include less averaging or filtering than what is performed for L3 measurement reports. L1 (or L1 / L2) measurement reports may be transmitted by a UE to a serving network node or source DU and may cause the network node to trigger or initiate a L1 / L2 triggered mobility (LTM) handover of the UE to another cell. L1 measurements (e.g., RSRP RSRQ, RSSI) may be provided or reported periodically to the DU (MAC / PHY).

[0043] In an example, sounding reference signal (SRS) transmissions and non-zero power (NZP)- CSI-RS measurements may be used for assessing the channel quality, performing measurements related to beam management and mobility, and / or the like. For example, the CSI components may include at least one of the following: channel quality information (CQI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), synchronization signal SS / PBCH resource block indicator (SSBRI), layer indicator (LI), rank indicator (Rl), L1-RSRP, and / or the like.

[0044] A configured NZP-CSI-RS resource may correspond to up to 32 NZP-CSI-RS antenna ports in NR. For example, there may be up to 32 different antenna ports multiplexed in time and frequency within the overall CSI-RS resource.

[0045] In wireless communications, an antenna port may represent a unique logical interface through which signals may be transmitted or received by a physical antenna or a group of antennas. For 5G NR, the use of different antenna ports may enable various transmission and reception scenarios, allowing for advanced functionalities like beamforming, MIMO (Multiple Input Multiple Output), and more.

[0046] In an example, the UE may use antenna ports associated with the reference signal resource(s) for channel estimation for downlink transmissions and for determining related channel state information (CSI). In other words, each individual downlink transmission of reference signal or channel may be carried out by using a specific antenna port, the identity of which is known to the UE.

[0047] In an example, a structure in the antenna port numbering may be used such that antenna ports for different purposes have numbers in different ranges. For example, downlink antenna ports starting with 1000 may be used for PDSCH. Different transmission layers for PDSCH can use antenna ports in this series, for example 1000 and 1001 for a two-layer PDSCH transmission. In an example, downlink antenna ports in the 3000 series may be used for the CSI-RS.

[0048] In an example, a UE may have more physical antennas than antenna ports for FR1. In an example, a UE may have more physical antenna arrays than antenna ports, where each array may have a high number of configurable analog beams (4 to 7) for mmWave antenna arrays that may support 2 antenna ports in downlink and 1 antenna port in uplink.

[0049] In an example, antenna configuration may include information of how many antennas / antenna arrays / analog beams can be configured for the radio frequency (RF) Front-End.

[0050] In an example, a fixed wireless access (FWA) may be employed to reduce cost, reduce power consumption and to enhance capacity and coverage by exploiting its lack of (reduced) mobility.

[0051] FIG. 2 is a diagram illustrating an example FWA deployment scenario with a customer premise equipment (CPE) mounted outdoor servicing multiple indoor devices. In an example, FWA may be beneficial due to some enhancements and advantages such as: high throughput (e.g., due to large bandwidth available at mmWave frequencies, modulation schemes (e.g., 4096QAM DL, 1024QAM UL), MIMO, beamforming, and / or the like), low latency, CPE simplification, energy efficiency, and / or the like. FWA spectrum may include 2.6 GHz and 3.5 GHz bands with 100+ MHz bandwidths in addition to upper midband (7-15 GHz) and upper 6 GHz band. In an example, for line of sight (LOS) connections it is also possible to take advantage of frequency range 2 (FR2) spectrum by exploiting the large bandwidths (e.g., 800 MHz aggregated) of millimetre wave (mmWave) by using a high antenna gain customer premise equipment (CPE), device, UE, and / or the like. In an example, the FR2 range may be 24.25 GHz to 52.6 GHz. FR2 may also be referred to as the mmWave spectrum.

[0052] FIG. 3 is a diagram illustrating a beam alignment procedure. In an example, the gNB may use 32 beams for the SSB burst configured on a 16 x 16 element antenna array. In an example, the UE may be a FWA CPE. 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). At Synchronization phase, the gNB may sweep 32 SSB beams in each SSB burst in a 1-15-16 grid of beam (GoB) pattern.

[0053] FIG. 4 is a diagram illustrating a grid of beam pattern for 32 SSBs. As shown in the figure, where the solid lines represent a high additional antenna gain (+12 dB) and the dotted line represents a low additional antenna gain (+ 0 dB). In an example, a grid of beam pattern azimuth is a two-dimensional representation of an antenna's azimuth beam pattern. The azimuth beam pattern may be calculated by cutting a spherical surface with a specified elevation angle.

[0054] In an example, a UE / CPE may typically need to average 2 to 6 measurements of the SSB beams to countereffect fast fading of the channel, which means the UE / CPE will have to wait for 2 to 6 full SSB bursts before it can determine the best SSB beam for transmitting the preamble (msg1) at the specified RACH occasion (RO). For example, the default periodicity for SSB bursts in 5G may be 20 ms.

[0055] As shown in FIG. 3, phase#1 may include a random access channel (RACH) procedure. At phase#1, the UE / CPE may send a preamble (Msg1) as defined by the master information block (MIB) and / or the system information block (SIB) for the chosen best SSB beam. In an example, at phase#1 the UE may receive a random access response (RAR) or Msg2. The UE may transmit a radio resource control (RRC) request e.g., a Msg3. In an example, at phase#1, the UE may receive a RRC setup message e.g., a msg4 (based on a 4-step RACH).

[0056] At phase#2 of FIG. 3, a CSI Refinement procedure may be performed. The UE may receive s channel state information reference signal (CSI-RS) from the gNB.

[0057] At phase#3 of FIG. 3, a UE / CPE beam alignment may be performed. In an example, the gNB may be configured with CSI-RS with repetition set to "ON” e.g., repetition enabled. In an example, enabling repetition of the CSI-RS may be required for enabling the UE to perform beam alignment and the number of CSI-RSs for this phase may depend on the antenna array implementation at the UE / CPE. The UE / CPE may transmit data to the gNB based on the aligned beam.

[0058] The current maximum number of allowed SSB beams for a specified carrier frequency is specified as shown in Table 1.Table 1 : Maximum number of SSBs within an SSB burst for different frequency carriers as specified for 5G.

[0059] A high number of SSB beams within an SSB burst is only seen in 5G for the commercialized FR2 frequency bands from 24.2 GHz to 52.6 GHz (also referred to as mmWave) and are typically implemented with large antenna arrays at the gNB (typically up to 16x16 for 5G and expected to increase for 6G to 32x32 or 64+64) and small antenna arrays at the UEs / CPEs (1 x4, 2x2 or 1 x5 for handheld devices and 8x8 for CPEs), to improve the communication link by increasing the antenna gain at both the gNB and the UE / CPE.

[0060] The 6G standard may include new frequency ranges compared to 5G. These new potential frequency ranges may be as follows:4400 MHz -+ 4800 MHz7125 MHz ^ 8400 MHz14800 MHz -^ 15350 MHz

[0061] This may include new bands above 6 GHz that might need more than 8 SSB beams within an SSB burst. In addition, larger antenna apertures at the 6G gNBs may be employed to increase coverage and SINR for both downlink (DL) and uplink (UL) communication. Increasing the antenna aperture may result in beams with higher antenna gain, but at the same time smaller radiation beamwidth and may increase the need for a higher number SSB beams within an SSB burst to successfully cover the full sector with increased antenna gain.

[0062] 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.

[0063] Taking the above into account, (a 6G version of) the maximum number of SSB beams within an SSB burst may be as shown in Table 2.Table 2: Envisioned maximum number of SSBs within an SSB burst for different frequency carriers for 6G.

[0064] As a result, the potential increase of the allowed maximum number of SSB beams within an SSB burst, may cause challenges for the beam alignment procedure.

[0065] FIG. 5 is a diagram illustrating an example FWA deployment scenario with different inter-site distance (ISD) for FR1 and FR2 gNBs. A FWA deployment as shown in the figure may be for a network with both lower frequency (LrF) and higher frequency (HrF) support, e.g., FR1 and FR2. As shown in the figure, some gNBs may support FR1 and FR2, some gNBs may only support FR1 and some gNBs may only support FR2. The inter site distance (ISD) for obtaining full FR2 coverage may be smaller than that for full FR1 coverage and thus it is a likely scenario that network planning involves non-co-located FR1 and FR2 gNBs.

[0066] In an example, deploying a FWA network at FR2 mmWave beam alignment may need to be established once between CPE / UE and best FR2 gNB and as long as static conditions remain valid, the CPE / UE beam configuration may be maintained for each re-establishment of RRC connection after either RRC-inactive state / mode, RRC-idle state / mode, or power-off state / mode.

[0067] Using the existing techniques of beam alignment procedures, the CPE / UE may measure the SSB beams in the SSB bursts from the FR2 gNBs and these SSB bursts may be transmitted every 20 ms (by default). In other words, as shown in FIG. 3, a first-time full sweep RACH procedure may involve 32 SSB transmissions and 6 CSI-RS transmissions for CPE / UE beam refinement and beam alignment in addition to RRC signaling such as re-establishments of the RRC connection. In an example, a reduction may be achieved by using a technique based on last best beam (LBB) RACH. In the LBB, the signaling may include 32 SSB transmissions and 1 CSI-RS transmission, e.g., a reduction of 5 CSI-RS transmissions. However, higher frequency ranges (e.g., mmWave frequencies) may pose challenges due to potential signaling overhead of the beam alignment procedures that may further degrade the performance of a communication system. It is therefore beneficial to reduce / minimize the number of required gNB transmissions for CPE / UE beam alignment and RACH at mmWave frequencies or the higher FR1 frequency ranges. As a result, the gNB operation may be optimized by improvement of gNB power efficiency and speed (reduced delay) of FWA connection / link re-establishment.

[0068] FIG. 6 is diagram illustrating an example scenario with UE / CPE synchronization anchor in FR1 for configuration of FR2 beam alignment RACH. In an example, the network and UE / CPEs may support both LrF (FR1) and HrF (FR2) with full coverage in at least the FR1 frequency range. To obtain full coverage, the ISD at FR2 may be smaller than the ISD in FR1 . Therefore, FRIand FR2 gNBs are not all co-located. In an example, the network is assumed to know the physical coordinates and antenna panels / sector orientations for all FR1 / FR2 gNBs.

[0069] Example embodiments are directed to enabling the UE / CPE to maintain network synchronization on a first carrier such as FR1 and / or via FR1 Uu interface (e.g., the interface between theg N B and the UE). In an example, the FR1 Uu interface may be between the UE / CPE and a first network node or a first gNB. In an example, the CPE / UE may use a second carrier e.g., via a FR2 Uu interface as high throughput data pipe when needed. In an example, the FR2 Uu interface may be between the UE and a second network node (or a second gNB). In other words, data communication on the second carrier or over FR2 Uu interface may be enabled by FR1 signaling (e.g., on the first carrier with a first network node or gNB) without any beamformed periodic SSB burst transmissions in FR2. Thus, as initial state (or starting point), the UE / CPE may be camped and synchronized to the network in FR1 over Uu interface. In an example, based on FIG. 6, the first network node may be a FR1 gNB e.g., gNB2, and the second network node may be a FR2 gNB e.g., gNB4 as depicted in FIG. 6.

[0070] Therefore, when example embodiments are implemented, signaling is reduced due to reduction and / or elimination of periodic SSB transmissions in FR2. For example, the number of FR2 transmissions required for FR2 synchronization, RACH and beam alignment is significantly reduced. In other words, example embodiments are advantageous due to removal of periodic FR2 SSB transmissions. Elimination of periodic FR2 SSB transmissions may results in reducing resource overhead, lower power consumption, lower connection or link re-establishment latency, and / or the like. Furthermore, a significant reduction of FR2 CSI-RS transmissions for connection / link re-establishment in static deployment scenarios like FWA may further enhance the performance of the system when FWA is deployed.

[0071] In other words, example embodiments are directed to enhancement of LBB beam alignment procedure by utilizing a FR1 gNB for signaling, control, synchronization, and / or the like while utilizing a FR2 gNB for high throughput data communication. In an example embodiment, a UE may transmit on a first carrier (e.g., FR1) to a first network node, an indication of support for second carrier beam alignment. In an example, the indication may include information associated with an antenna. In an example, the UE may receive from the first network node on the first carrier, synchronization information for performing a random access on a second carrier with a second network node.

[0072] In an example, the indication of support for second carrier beam alignment may include indication of support for the FR2 beam alignment procedure, wherein the beam alignment procedure may be performed with the second network node such as FR2 gNB4 of FIG. 6.

[0073] In an example embodiment, a network node (e.g., the first network node and / or the second network node) may include a gNB-DU, a cell of a gNB, a cell of a master cell group of a gNB, a cell of a secondary cell group of a gNB, a first carrier of a gNB, a second carrier of the gNB, and / or the like.

[0074] In an example embodiment, the information associated with the antenna may include at least one of a configuration related to the antenna, a number of antennas configured for RF front-end, a number of random access preambles required on the second carrier, a number of antennas supporting a frequency range of the second carrier, a number of antenna arrays supporting the frequency range of the secondcarrier, a number of configurable analog beams for the frequency range of the second carrier, a number of antenna ports supporting the frequency range of the second carrier, and / or the like.

[0075] In an example embodiment, the information associated with the antenna may include the number of antennas and / or antenna arrays supporting the second carrier e.g., a second frequency range or FR2. In an example, the information of the number antennas may be indicative of the number of preambles being transmitted by the UE. For example, the number of antennas / antenna arrays may be employed by the UE to send a preamble for maximum coverage.

[0076] In an example, the synchronization information may include at least one of: a master information block (MIB), system information (SI); a system information block (SIB), a type of random access channel (RACH) (wherein the type comprises a last best beam (LBB) RACH), information of timing advance (TA), or information of synchronization signal block (SSB), and / or the like.

[0077] In an example, the UE may transmit a random access request. In an example, the random access request may be transmitted on an antenna to the second network node. In an example, the UE may receive from the second network node, a random access response (RAR). In an example, the UE may transmit a radio resource control (RRC) request message to the second network node. In an example, the UE may receive a RRC setup message from the second network node. In an example, the antenna may be an antenna on which a signal was last received, e.g., last best FR2 antenna / sector and / or last best beam configuration.

[0078] In an example, the first carrier may be on a first frequency range (e.g., FR1), and the second carrier may be on a second frequency range (e.g., FR2).

[0079] In an example, the second network node may be a second network node from which a reference signal was last received, e.g., a last used FR2 gNB which may be the gNB in proximity of the UE / CPE. The gNB in proximity of the UE / CPE may be the gNB with strongest signal, best RSRP, and / or the like.

[0080] In an example, embodiment, the UE may receive from the second network node, at least one channel state information reference signal (CSI-RS).

[0081] FIG. 7 is a diagram illustrating an example LBB RACH beam alignment procedure for analog beam alignment. The procedure may be performed at every re-establishment of a RRC connection on the FR2 for transmission and / or reception of data. At initial step 730, synchronization on FR1 may be performed by the UE with a first network node on FR1 . The UE / CPE may use the best FR1 antenna and the first network node may use the best FR1 antenna beam. The UE may transmit on a first carrier (e.g., FR1) to a first network node, an indication of support for second carrier beam alignment. In an example, the indication may include information of (or associated with) an antenna. In an example embodiment, the information associated with the antenna may include at least one of a configuration related to the antenna, a number of antennas configured for RF front-end, a number of random accesspreambles required on the second carrier, a number of antennas supporting a frequency range of the second carrier, a number of antenna arrays supporting the frequency range of the second carrier, a number of configurable analog beams for the frequency range of the second carrier, a number of antenna ports supporting the frequency range of the second carrier, and / or the like. In other words, the UE may provide capability report to the first network node indicating support for the FR2 beam alignment procedure with support for x antennas (e.g., 4 antennas in this example). In an example, the UE may receive from the first network node on the first carrier (FR1), synchronization information for performing a random access on a second carrier with a second network node. For example, the network may trigger FR2 link re-establishment and beam alignment via an FR1 Uu that may include required FR2 synchronization information such as Ml Bs / SIBs and type of RACH (e.g., LBB RACH).

[0082] At phase#1 740 of FIG. 7, a relevant gNB with a proximity of the UE / CPE may be selected by the network. The relevant gNB may be the last used FR2 gNB. For example, the FR2 gNB may be configured by the network to listen for UE / CPE random access request or msg1 with last best FR2 antenna sector and beam configuration. In an example, the UE / CPE may transmit msg1 once on the last used FR2 antenna and beam configuration. For example, the UE may transmit one random access request (or msg1). In an example, the UE may receive a RAR from the second network node on FR2. In an example, the UE may transmit on FR2, a RRC request message to the second network node. The UE may receive on FR2 from the second network node a RRC setup message.

[0083] At phase#2 750 of FIG. 7, the UE may receive on the FR2 carrier (from the second network node) at least one CSI-RS for channel estimation. For example, the number of CSI-RSs may be one CSI- RS. At 760, the UE may transmit data to the second network node using the last best beam on FR2.

[0084] As a result, in the example of FIG. 7, the total number of messages is reduced to 0 SSB + 1 CSI-RS + 1 msg1.

[0085] Example embodiments are also directed to enhancement of full RACH beam alignment procedure by utilizing a FR1 gNB for signaling, control, synchronization, and / or the like while utilizing a FR2 gNB for high throughput data communication. In an example embodiment, the UE may transmit on a first carrier (FR1) to a first network node, an indication of support for second carrier beam alignment. In an example, the indication may include information associated with a plurality of antennas. In an example embodiment, the information associated with the plurality of antennas may include at least one of a configuration related to the plurality of antennas, a number of antennas or plurality of antennas configured for RF front-end, a number of random access preambles required on the second carrier, a number of antennas or plurality of antennas supporting a frequency range of the second carrier, a number of antenna arrays supporting the frequency range of the second carrier, a number of configurable analog beams for the frequency range of the second carrier, a number of antenna ports or a plurality of antenna ports supporting the frequency range of the second carrier, and / or the like. In an example, the UE may receiveon the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0086] In an example, the information associated with the plurality of antennas may include information of the number of random access preambles required on the second carrier, the plurality of antennas for simultaneous reception of signals, and / or the like. In an example, the information of the plurality of antennas may indicate a number of supported simultaneous downlink carriers. The information of the number of random access preambles may be employed by the network for allocation of preambles, and a number of RARs.

[0087] In an example embodiment, the information of the plurality of antennas may include information of the plurality antennas that cover a frequency range of the second carrier.

[0088] In an example embodiment, the information of the plurality of antennas may include the number of antennas and / or antenna arrays supporting the second carrier, e.g., a second frequency range or FR2. In an example, the information the antenna may be indicative of the number of preambles being transmitted by the UE. For example, the number of antennas / antenna arrays may be employed by the UE to send a preamble for maximum coverage.

[0089] In an example embodiment, the synchronization information may include at least one of a master information block (Ml B), system information (SI), a system information block (SIB) a type of random access channel (RACH) such as a full RACH, an allocation of one or more random access channel (RACH) preambles, information of timing advance (TA), information of synchronization signal block (SSB), and / or the like.

[0090] In an example, one or more corresponding second network nodes of the plurality of second network nodes may listen for preambles. In an example embodiment, the UE may transmit a random access request that may be received by a corresponding second network node of the plurality of second network nodes. For example, the UE may transmit a plurality of random access requests that may be received by a plurality of second networks nodes such that each random access request of the plurality of random access requests may be received by a corresponding second network node of the plurality of second network nodes. In an example, the UE may send the random access request on at least one antenna of the plurality of antennas that may be received by a corresponding second network node of the plurality of second network nodes. In an example, the UE may receive from the corresponding second network node of the plurality of second network nodes, one or more random access responses (RARs). In an example, the UE may receive the one or more RARs on the at least one antenna of the plurality of antennas. In other words, each second network node of the plurality of second network nodes may send a RAR. In an example, the UE may transmit a radio resource control (RRC) request message to the corresponding second network node. In an example, the UE may receive one or more RRC setup message from the corresponding second network node.

[0091] In an example embodiment, the first carrier may be on a first frequency range such as FR1 , and the second carrier may be on a second frequency range such as FR2.

[0092] In an example, the UE may receive from the plurality of second network nodes, at least one channel state information reference signal (CSI-RS).

[0093] FIG. 8 is a diagram illustrating an example full RACH beam alignment procedure for analog beam alignment. At initial step 830, synchronization on FR1 may be performed by the UE with a first network node on FR1. In an example, the UE / CPE may transmit on a first carrier (FR1) to a gNB e.g., a first network node, an indication of support for second carrier (FR2) beam alignment. In an example, the indication may include information associated with a plurality of antennas. In an example embodiment, the information associated with the plurality of antennas may include at least one of a configuration related to the plurality of antennas, a number of antennas or the plurality of antennas configured for RF front-end, a number of random access preambles required on the second carrier, a number of antennas or plurality of antennas supporting a frequency range of the second carrier, a number of antenna arrays supporting the frequency range of the second carrier, a number of configurable analog beams for the frequency range of the second carrier, a number of antenna ports or plurality of antenna ports supporting the frequency range of the second carrier, and / or the like. In an example, the indication may include information of a plurality of antenna ports. In other words, the UE / CPE may use the best FR1 antenna, and the FR1 gNB may use the best FR1 antenna beam. In an example, the UE / CPE may provide / transmit capability report to the first network node (FR1 gNB) indicating support for the FR2 beam alignment procedure. The capability indication may also indicate support for x antennas, or antennas panels (e.g., 4 antennas in this example). The indication may further be indicative of a number of antennas / panels that can be active for reception at the same time, e.g., simultaneous reception. In an example, the indication may further be indicative of a number of required preambles. In an example, based on the indicated number of required preambles, the network may allocate the required number of preambles. In an example, the UE may receive from the gNB (first network node) on the first carrier (FR1), synchronization information for performing a random access on the second carrier (FR2). In an example, the first network node may trigger FR2 link establishment and beam alignment via an FR1 Uu request that may include required FR2 synchronization information including MIBs / SIBs and type of RACH (e.g., Full RACH), the allocation of one or more preambles, and / or the like.

[0094] At phase#1 840 of FIG. 8, relevant gNBs (FR2 gNBs) that are within a proximity of the UE / CPE may be identified, e.g., based on UE / CPE FR1 TA, monitoring of FR1 SSB and / or based on FR1 positioning sessions. In an example, the network may identify the relevant gNBs and may trigger or notify the FR2 gNBs to listen for random access request(s) from the UE / CPE. In other words, the identified FR2 gNB may be configured by the network to listen for UE / CPE msg1 with best FR2 antenna sector based on best FR1 beam and available UE / CPE location information. The gNB may configure a beam that cover thefull sector or the part of the sector with (based on) the estimated location of the UE / CPE. In an example, the UE may transmit a random access request (msg1) once for each supported antenna. For example, if there are x=4 antennas in this example, then the UE may send msg1 4 times once on each antenna. As a result, the gNB may send one or more msg2, e.g., RARs using the same beam as for msg1 reception. In an example, the number of RARs may be based on the number of required preambles indicated by the UE. This step may depend on the reported number of UE antennas, antennas / panels, and / or the like and the number of simultaneously receiver path at the UE / CPE. The UE / CPE may transmit msg1 once for each supported antenna (4x in this example) and then completes the RACH procedure by msg2, msg3, and msg4. For example, the UE may transmit to the FR2 gNB, e.g., the second network node, a RRC request message. The UE may receive from the second network node (FR2 gNB) a RRC setup message.

[0095] At phase#2 850 of FIG. 8, FR2 gNB beam refinement may be executed by the second network node with CSI-RS beam sweeping (e.g., 16 CSI-RS sweeps in this example). At phase#3 860, a UE / CPE beam alignment may be performed. In an example, the FR2 gNB may be configured with CSI-RS with repetition set to "ON”, e.g., repetition enabled. In an example, enabling repetition of the CSI-RS may be required for enabling the UE to perform beam alignment and the number of CSI-RSs for this phase may depend on the antenna array implementation at the UE / CPE. At 860, The UE / CPE may transmit data to the gNB based on the aligned beam.

[0096] Therefore, when example embodiments are implemented, signaling is reduced due to reduction and / or elimination of periodic SSB transmissions in FR2. As shown in the following table (Table 3), the number of FR2 transmissions required for FR2 synchronization, RACH and beam alignment is significantly reduced.Table 3: Summary of FR2 transmissions for 5G standard and 6G proposed procedure examples.

[0097] It is therefore evident from Table 3 that elimination of periodic SSB transmissions in FR2 results in a sizeable reduction of resource overhead and power consumption. For the case of a static FWA application, the CSI-RS transmissions in the LBB RACH are reduced significantly from 6 to 1.

[0098] In other words, example embodiments are advantageous due to removal of periodic FR2 SSB transmissions that results in reducing resource overhead, power consumption, connection or link reestablishment latency, and / or the like. Furthermore, a significant reduction of FR2 CSI-RS transmissions for connection / link re-establishment in static deployment scenarios like FWA may further enhance the performance of the system when FWA is deployed.

[0099] In an example, a digital beam forming and / or a digital beam alignment may be employed. The major difference between an implementation of analog beam alignment and a digital beam alignment is the absence of Phase#3 in the RACH procedures.

[0100] Example embodiments may be applicable to the LBB RACH beam alignment procedure for digital beam alignment, and the full RACH beam alignment procedure for digital beam alignment.

[0101] FIG. 9 is a diagram illustrating a LBB RACH beam alignment procedure for digital beam alignment. Steps of LBB RACH beam alignment procedure for digital beam alignment is similar to the steps or procedure of FIG. 7 with a difference wherein phase#3 is absent in the LBB RACH beam alignment procedure for digital beam alignment. Digital beam alignment may be based on pre-coding of the radio frequency (RF) signals received / transmitted from each antenna. For example, the pre-coding values may be derived by the UE (e.g., none-Codebook-Based) or may be derived by the gNB (e.g., Codebook-Based) and transmitted to the UE.

[0102] FIG. 10 is a diagram illustrating a full RACH beam alignment procedure for digital beam alignment. Steps of full RACH beam alignment procedure for digital beam alignment is similar to the steps or procedure of FIG. 8 with a difference wherein phase#3 is absent in the full RACH beam alignment procedure for digital beam alignment. Digital beam alignment may be based on pre-coding of the radio frequency (RF) signals received / transmitted from each antenna. For example, the pre-coding values may be derived by the UE (e.g., none-Codebook-Based) or may be derived by the gNB (e.g., Codebook-Based) and transmitted to the UE.

[0103] Some examples will now be described, based on the description and figures provided herein.

[0104] Example 1 . An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: transmitting on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and receiving on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

[0105] Example 2. The apparatus of Example 1, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0106] Example 3. The apparatus of Example 1 or 2, wherein the apparatus is further caused to perform transmitting a random access request on an antenna to the second network node.

[0107] Example 4. The apparatus of any of Examples 1 to 3, wherein the apparatus is further caused to perform: receiving from the second network node, a random access response on an antenna; transmitting a radio resource control (RRC) request message to the second network node on the antenna; and receiving a RRC setup message from the second network node on the antenna.

[0108] Example 5. The apparatus of Example 4, wherein the antenna comprises an antenna on which a signal was last received.

[0109] Example 6. The apparatus of any of Examples 1 to 5, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0110] Example 7. The apparatus of any of Examples 1 to 6, wherein the second network node is a second network node from which a reference signal is last received.

[0111] Example 8. The apparatus of any of Examples 1 to 7, wherein the apparatus is further caused to perform receiving from the second network node, at least one channel state information reference signal (CSI-RS).

[0112] Example 9. The apparatus of any of Examples 1 to 8, wherein the synchronization information comprises at least one of: a master information block (Ml B); system information (SI); a system information block (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

[0113] Example 10. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and transmitting on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.

[0114] Example 11 . The apparatus of Example 10, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting thefrequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0115] Example 12. The apparatus of Example 10 or 11 , wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0116] Example 13. The apparatus of any of Examples 10 to 12, wherein the second network node is a second network node from which a reference signal is last received by the user device.

[0117] Example 14. The apparatus of any of Examples 10 to 13, wherein the synchronization information comprises at least one of: a master information block (MIB); system information (SI); a system information block (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

[0118] Example 15. The apparatus of any of Examples 10 to 14, wherein the apparatus is further caused to perform selecting the second network node based on proximity between the user device and the second network node.

[0119] FIG. 11 is a flow chart illustrating operation of an apparatus (e.g., which may be a UE or user device, or other apparatus) according to an example embodiment. The flowchart of FIG. 11 illustrates operation of the apparatus as described in Example 16.

[0120] Example 16. FIG. 11 is a flow chart illustrating operation of an apparatus (e.g., which may be a UE or user device, or other apparatus) according to an example embodiment. At step 1110, the method may include: transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna. At step 1120, the method may include receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

[0121] Example 17. The method of Example 16, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0122] Example 18. The method of Example 16 or 17, further comprising transmitting a random access request on an antenna to the second network node.

[0123] Example 19. The method of any of Examples 16 to 18, further comprising: receiving from the second network node, a random access response on an antenna; transmitting a radio resource control (RRC) request message to the second network node on the antenna; and receiving a RRC setup message from the second network node on the antenna.

[0124] Example 20. The method of Example 19, wherein the antenna comprises an antenna on which a signal was last received.

[0125] Example 21 . The method of any of Examples 16 to 20, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0126] Example 22. The method of any of Examples 16 to 21, wherein the second network node is a second network node from which a reference signal is last received.

[0127] Example 23. The method of any of Examples 16 to 22, further comprising receiving from the second network node, at least one channel state information reference signal (CSI-RS).

[0128] Example 24. The method of any of Examples 16 to 23, wherein the synchronization information comprises at least one of: a master information block (Ml B); system information (SI); a system information block (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

[0129] FIG. 12 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. The flowchart of FIG. 12 illustrates operation of the apparatus as described in Example 25.

[0130] Example 25. FIG. 12 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. At step 1210, the method may include receiving, by a first network node on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna. At step 1220, the method may include transmitting, by the first network node on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.

[0131] Example 26. The method of Example 25, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0132] Example 27. The method of Example 25 or 26, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0133] Example 28. The method of any of Examples 25 to 27, wherein the second network node is a second network node from which a reference signal is last received by the user device.

[0134] Example 29. The method of any of Examples 25 to 28, wherein the synchronization information comprises at least one of: a master information block (MIB); system information (SI); a system informationblock (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

[0135] Example 30. The method of any of Examples 25 to 29, further comprising: selecting the second network node based on proximity between the user device and the second network node.

[0136] Example 31 . An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: transmitting on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and receiving on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0137] Example 32. The apparatus of Example 31 , wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0138] Example 33. The apparatus of Example 31 or 32, wherein the apparatus is further caused to perform: transmitting one or more random access requests on one or more antennas to one or more corresponding second network node of the plurality of second network nodes.

[0139] Example 34. The apparatus of Example 33, wherein the apparatus is further caused to perform: receiving from the one or more corresponding second network node of the plurality of second network nodes, one or more random access responses on one antenna ; transmitting a radio resource control (RRC) request message to the one or more corresponding second network node, on the one antenna; and receiving one or more RRC setup message from the one or more corresponding second network node, on the one antenna.

[0140] Example 35. The apparatus of any of Examples 31 to 33, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0141] Example 36. The apparatus of any of Examples 31 to 35, wherein the apparatus is further caused to perform receiving from the plurality of second network nodes, at least one channel state information reference signal (CSI-RS).

[0142] Example 37. The apparatus of any of Examples 31 to 36, wherein the synchronization information comprise at least one of: a master information block (MIB); system information (SI); a system information block (SIB); an allocation of one or more random access channel (RACH) preambles; a type of random access channel (RACH), wherein the type comprises a full RACH; information of timing advance; or information of synchronization signal block (SSB).

[0143] Example 38. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and transmitting on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0144] Example 39. The apparatus of Example 38, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0145] Example 40. The apparatus of Example 38 or 39, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0146] Example 41 . The apparatus of any of Examples 38 to 40, wherein the synchronization information comprise at least one of: a master information block (MIB); system information (SI); a system information block (SIB); an allocation of one or more random access channel (RACH) preambles; a type of random access channel (RACH), wherein the type comprises a full RACH; information of timing advance; or information of synchronization signal block (SSB).

[0147] Example 42. The apparatus of any of Examples 38-41 , wherein the apparatus is further caused to perform: selecting the plurality of second network nodes based on at least one of: timing advance of the user device on the first carrier, SSB monitoring of the user device on the first carrier, or positioning session of the user device on the first carrier.

[0148] FIG. 13 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. The flowchart of FIG. 13 illustrates operation of the apparatus as described in Example 43.

[0149] Example 43. FIG. 13 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. At step 1310, the method may include transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna. At step 1320, the method may include receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0150] Example 44. The method of Example 43, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RFfront-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0151] Example 45. The method of Example 43 or 44, further comprising: transmitting one or more random access requests on one or more antennas to one or more corresponding second network node of the plurality of second network nodes.

[0152] Example 46. The method of Example 45, further comprising: receiving from the one or more corresponding second network node of the plurality of second network nodes, one or more random access responses on one antenna; transmitting a radio resource control (RRC) request message to the one or more corresponding second network node, on the one antenna; and receiving one or more RRC setup message from the one or more corresponding second network node, on the one antenna.

[0153] Example 47. The method of any of Examples 43 to 45, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0154] Example 48. The method of any of Examples 43 to 47, further comprising receiving from the plurality of second network nodes, at least one channel state information reference signal (CSI-RS).

[0155] Example 49. The method of any of Examples 43 to 48, wherein the synchronization information comprise at least one of: a master information block (MIB); system information (SI); a system information block (SIB); an allocation of one or more random access channel (RACH) preambles; a type of random access channel (RACH), wherein the type comprises a full RACH; information of timing advance; or information of synchronization signal block (SSB).

[0156] FIG. 14 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. The flowchart of FIG. 14 illustrates operation of the apparatus as described in Example 50.

[0157] Example 50. FIG. 14 is a flow chart illustrating operation of an apparatus (e.g., which may be a gNB or network node, or other apparatus) according to an example embodiment. At step 1410, the method may include receiving, by a first network node on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna. At step 1420, the method may include transmitting, by the first network node on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a plurality of second network nodes.

[0158] Example 51 . The method of Example 50, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequencyrange of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

[0159] Example 52. The method of Example 50 or 51, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

[0160] Example 53. The method of any of Examples 50 to 52, wherein the synchronization information comprise at least one of: a master information block (MIB); system information (SI); a system information block (SIB); an allocation of one or more random access channel (RACH) preambles; a type of random access channel (RACH), wherein the type comprises a full RACH; information of timing advance; or information of synchronization signal block (SSB).

[0161] Example 54. The method of any of Examples 50-53, further comprising: selecting the plurality of second network nodes based on at least one of: timing advance of the user device on the first carrier, SSB monitoring of the user device on the first carrier, or positioning session of the user device on the first carrier.

[0162] FIG. 15 is a block diagram of a wireless station or node (e.g., UE, user device, AP, BS, eNB, gNB, RAN node, network node, TRP, or other node) 1300 according to an example embodiment. The wireless station 1300 may include, for example, one or more (e.g., two as shown in FIG. 15) RF (radio frequency) or wireless transceivers 1302A, 1302B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit / entity (controller) 1304 to execute instructions or software and control transmission and receptions of signals, and a memory 1306 to store data and / or instructions.

[0163] Processor 1304 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 1304, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 1302 (1302A or 1302B). Processor 1304 may control transmission of signals or messages over a wireless network, and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down- converted by wireless transceiver 1302, for example). Processor 1304 may be programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 1304 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and / or any combination of these. Using other terminology, processor 1304 and transceiver 1302 together may be considered as a wireless transmitter / receiver system, for example.

[0164] In addition, referring to FIG. 15, a controller (or processor) 1308 may execute software and instructions, and may provide overall control for the station 1300, and may provide control for other systems not shown in FIG. 15, such as controlling input / output devices (e.g., display, keypad), and / or may execute software for one or more applications that may be provided on wireless station 1300, such as, for example, an email program, audio / video applications, a word processor, a Voice over IP application, or other application or software.

[0165] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 1304, or other controller or processor, performing one or more of the functions or tasks described above.

[0166] According to another example embodiment, RF or wireless transceiver(s) 1302A / 1302B may receive signals or data and / or transmit or send signals or data. Processor 1304 (and possibly transceivers 1302A / 1302B) may control the RF or wireless transceiver 1302A or 1302B to receive, send, broadcast or transmit signals or data.

[0167] Example embodiments are provided or described for each of the example methods, including: An apparatus (e.g., 1300, FIG. 15) including means (e.g., processor 1304, RF transceivers 1302A and / or 1302B, and / or memory 1306, in FIG. 15) for carrying out any of the methods; a non-transitory computer-readable storage medium (e.g., memory 1306, FIG. 15) comprising instructions stored thereon that, when executed by at least one processor (processor 1304, FIG. 15), are configured to cause a computing system (e.g., 1300, FIG. 15) to perform any of the example methods; and an apparatus (e.g., 1300, FIG. 15) including at least one processor (e.g., processor 1304, FIG. 15), and at least one memory (e.g., memory 1306, FIG. 15) including computer program code, the at least one memory (1306) and the computer program code configured to, with the at least one processor (1304), cause the apparatus (e.g., 1300) at least to perform any of the example methods.

[0168] Embodiments of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Embodiments may be implemented as a computer program product, i.e. , a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Embodiments may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Embodiments of the various techniques may also include embodiments provided via transitory signals or media, and / or programs and / or software embodiments that are downloadable via the Internet or other network(s), either wired networks and / or wireless networks. In addition, embodiments may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

[0169] As used in this application, the term "circuitry” or "circuit” refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of circuits and soft-ware (and / or firmware), such as (as applicable): (I) a combination of processor(s) or (ii) portions of processor(s) / software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of "circuitry” applies to all uses of this term in this application. As a further example, as used in this application, the term "circuitry” would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and / or firmware. The term "circuitry” would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

[0170] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and / or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer, or it may be distributed amongst a number of computers.

[0171] Furthermore, embodiments of the various techniques described herein may use a cyberphysical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the embodiment and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, ...) 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 cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber-physical systems. Therefore, various embodiments of techniques described herein may be provided via one or more of these technologies.

[0172] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0173] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0174] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magnetooptical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0175] To provide for interaction with a user, embodiments may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0176] Embodiments may be implemented in a computing system that includes a backend component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a frontend component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an embodiment, or any combination of such backend, middleware, or frontend components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[0177] While certain features of the described embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.

Claims

CLAIMSWHAT IS CLAIMED IS:1 . An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: transmitting on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and receiving on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

2. The apparatus of claim 1 , wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

3. The apparatus of claim 1 or 2, wherein the apparatus is further caused to perform transmitting a random access request on an antenna to the second network node.

4. The apparatus of any of claims 1 to 3, wherein the apparatus is further caused to perform: receiving from the second network node, a random access response on an antenna; transmitting a radio resource control (RRC) request message to the second network node on the antenna; and receiving a RRC setup message from the second network node on the antenna.

5. The apparatus of claim 4, wherein the antenna comprises an antenna on which a signal was last received.

6. The apparatus of any of claims 1 to 5, wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

7. The apparatus of any of claims 1 to 6, wherein the second network node is a second network node from which a reference signal is last received.

8. The apparatus of any of claims 1 to 7, wherein the apparatus is further caused to perform receiving from the second network node, at least one channel state information reference signal (CSI-RS).

9. The apparatus of any of claims 1 to 8, wherein the synchronization information comprises at least one of: a master information block (MIB); system information (SI); a system information block (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

10. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and transmitting on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.11 . The apparatus of claim 10, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna; a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier;a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

12. The apparatus of claim 10 or 11 , wherein the first carrier is on a first frequency range, and the second carrier is on a second frequency range.

13. The apparatus of any of claims 10 to 12, wherein the second network node is a second network node from which a reference signal is last received by the user device.

14. The apparatus of any of claims 10 to 13, wherein the synchronization information comprises at least one of: a master information block (MIB); system information (SI); a system information block (SIB); a type of random access channel (RACH), wherein the type comprises a last best beam (LBB) RACH; information of timing advance; or information of synchronization signal block (SSB).

15. The apparatus of any of claims 10 to 14, wherein the apparatus is further caused to perform selecting the second network node based on proximity between the user device and the second network node.

16. A method comprising: transmitting, by a user device on a first carrier to a first network node, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and receiving, by the user device on the first carrier from the first network node, synchronization information for performing a random access on a second carrier with a second network node.

17. The method of claim 16, wherein the information associated with the antenna comprises at least one of: a configuration related to the antenna;a number of antennas configured for RF front-end; a number of random access preambles required on the second carrier; a number of antennas supporting a frequency range of the second carrier; a number of antenna arrays supporting the frequency range of the second carrier; a number of configurable analog beams for the frequency range of the second carrier; or a number of antenna ports supporting the frequency range of the second carrier.

18. The method of claim 16 or 17, further comprising transmitting a random access request on an antenna to the second network node.

19. The method of any of claims 16 to 18, further comprising: receiving from the second network node, a random access response on an antenna; transmitting a radio resource control (RRC) request message to the second network node on the antenna; and receiving a RRC setup message from the second network node on the antenna.

20. A method comprising: receiving, by a first network node on a first carrier from a user device, an indication of support for second carrier beam alignment, wherein the indication comprises information associated with an antenna; and transmitting, by the first network node on the first carrier to the user device, synchronization information for performing a random access on a second carrier with a second network node.

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