SYSTEMS AND METHODS FOR BEAMFORMED UPLINK TRANSMISSIONS - Patent application

Abstract

The systems and methods described herein are provided for beamforming techniques and uplink control and data transmission techniques. The technique enables a UE to maintain at least one beam process for operation with multiple beams and / or points. The beam process may be indicated for transmission or reception on a downlink or uplink physical channel. Power, timing, and channel state information may be beam process specific. The beam process may be established as part of a random access procedure in which resources may be provisioned in a random access response message. Techniques are provided for handling beam process failure, for using beam processes for mobility, and for selecting a beam using open-loop and closed-loop selection procedures.

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a nonprovisional application claiming the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 62 / 334,754, entitled "Systems and Methods for Beamformed Uplink Transmission," filed May 11, 2016, U.S. Provisional Application No. 62 / 373,076, entitled "Systems and Methods for Beamformed Uplink Transmission," filed August 10, 2016, and U.S. Provisional Application No. 62 / 440,903, entitled "Systems and Methods for Beamformed Uplink Transmission," filed December 30, 2016. All of these applications are incorporated herein by reference in their entireties.

[0002] To meet the high data rates required for next generation cellular communication systems, the wireless industry and academia are exploring ways to take advantage of the large bandwidth available at higher frequencies, such as cmW and mmW frequencies.

[0003] These high frequencies may have unfavorable propagation characteristics for wireless communication, especially in outdoor environments. Higher frequency transmissions may experience higher free-space path loss. Precipitation and atmospheric gases (such as oxygen and foliage) may add further attenuation compared to sub-6 GHz frequencies. Furthermore, transmission and diffraction attenuation may be more severe at higher frequencies, such as at mmW frequencies.

[0004] All these propagation characteristics can result in significant non-line-of-sight (NLOS) propagation path loss. For example, at mmW frequencies, the NLOS path loss can be more than 20 dB higher than the line-of-sight (LOS) path loss, severely limiting the coverage of mmW transmissions. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Section 7.1.1 of 3GPP specification TR37.842, Radio Frequency Requirement Background for Active Antenna System Base Station, Release 13, v.1.8.0, October 2015 Summary of the Invention

[0006] To increase throughput and maintain sufficient coverage in higher frequency bands, New Radio (NR) systems use more UE antenna elements compared to legacy systems. For UEs using as many as 64 antenna elements, the overhead of transmitting up to 64 orthogonal reference signals and signaling precoders for up to 64 antenna ports makes legacy approaches to control multi-antenna transmissions infeasible. Exemplary embodiments enable a UE to determine a set of precoding weights and other parameters for uplink or sidelink transmissions.

[0007] Similarly, in the downlink direction, network equipment may be equipped with more antenna elements compared to legacy systems, making current approaches infeasible. Exemplary embodiments select precoding weights for reception (downlink or sidelink) as well as feedback to enable appropriate selection of precoding weights at the network side. Exemplary embodiments also enable other desirable design features of NR, such as not relying on continuous transmission of a common downlink reference signal, which results in low energy efficiency and limited spectral efficiency.

[0008] The use of narrow beam patterns during operation can cause the received energy to degrade rapidly during UE rotation and dynamic obstructions. Disclosed herein are methods implemented by the UE to adjust the beam and manage the beam process when the channel varies rapidly due to the UE's own rotation or dynamic obstructions during system procedures or active data transmission / reception.

[0009] Beamforming techniques and uplink control and data transmission techniques enable a UE to maintain at least one beam process for operation with multiple beams and / or points. A beam process may be indicated for transmission or reception on a downlink or uplink physical channel. Power, timing, and channel state information may be specific to a beam process. A beam process may be established as part of a random access procedure where resources may be provisioned in a random access response message. Techniques are provided for handling beam process failures, for using beam processes for mobility, for selecting beams using open-loop and closed-loop selection procedures, for simultaneous beam process power allocation, for beam process maximum power back-off (MPR) caused by, e.g., SAR, for beam reselection due to MPR, and for beam reselection and repair due to UE rotation and dynamic obstructions.

[0010] The systems and methods disclosed herein provide support for a large number of antenna elements at the UE side for use in 5G NR compared to legacy systems. The systems and methods disclosed herein further relate to efficient selection of precoding weights for UE reception and transmission. The exemplary beam-based NR systems and methods disclosed herein reduce reliance on continuous transmission of a common downlink reference signal to achieve energy and spectral efficiency.

[0011] In an exemplary embodiment, for operation with one or more beams and / or points, the UE maintains one beam process per beam and / or point. A beam process may be indicated for transmission / reception on a downlink or uplink physical channel. Power, timing, channel state information may be specific to a beam process. A beam process may be established as part of a random access procedure where resources may be provisioned in a random access response. The UE may monitor link quality specific to a beam process and may declare link failure of a beam process based on individual or aggregated beam quality. The UE may handle mobility based on the use of beam processes. The UE may perform a beam selection procedure for each beam process using (i) open loop, e.g., based on channel reciprocity, and / or (ii) closed loop, e.g., based on beam measurements. [Brief description of the drawings]

[0012] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 shows a three-dimensional graph of a beam pattern. [Diagram 2] FIG. 2 is a functional block diagram of a beamforming process. [Figure 3A] FIG. 13 illustrates an exemplary beam distribution pattern when the beam center direction is the same as the beam peak direction. [Figure 3B] FIG. 13 illustrates an exemplary beam distribution pattern when the beam center direction is not the same as the beam peak direction. [Figure 4] 1 is a schematic diagram of an exemplary embodiment of beam propagation; [Diagram 5] A diagram showing beam transmission patterns to indicate beam groups and beam classes. [Figure 6] FIG. 1 is a schematic diagram illustrating one embodiment of an uplink beam reselection of an active beam process influenced by SAR. [Figure 7A] FIG. 1 illustrates an example communication system in which one or more disclosed embodiments may be implemented. [Figure 7B] FIG. 7B illustrates an example radio access network (RAN) and an example core network that may be used within the communication system of FIG. 7A. [Figure 7C] FIG. 7B illustrates a second exemplary RAN and a second exemplary core network that may be used within the communications system of FIG. 7A. [Figure 7D] FIG. 7B illustrates a third exemplary RAN and a third exemplary core network that may be used within the communications system of FIG. 7A. [Figure 7E] FIG. 7B illustrates an example wireless transmit / receive unit (WTRU) that may be used within the communications system of FIG. 7A. [Figure 7F] 7B illustrates an example network entity that may be used within the communication system of FIG. 7A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 5G Beam-Based Wireless Access Recent channel measurements performed by the wireless industry and academia have proven the feasibility of satisfactory cellular coverage with the aid of beamforming techniques. The measurement data shows that beamforming gains provide coverage and boost link capacity that can be used for cellular control signaling to achieve higher data throughput in LOS conditions.

[0014] The channel propagation characteristics and extremely high data throughput for 5G NR cellular systems may require the use of beamforming on all physical layer signals and channels, including those for broadcast and common purposes, and focusing on beam-based or beam-centered procedures. The 5G NR system design may enable beamformed access links, with beamforming for most or all physical layer signals and channels. The physical layer signals and channels may apply different beamforming techniques, including digital beamforming, analog beamforming, and hybrid beamforming, and may store their unique beamforming configurations.

[0015] Beamforming may provide additional degrees of freedom in the angular domain compared to conventional cellular systems. The system design may take into account the beamforming and beam-based features specific to each physical layer signal and channel, and incorporate corresponding control and system procedures (such as uplink transmission, cell search, random access, and control channel decoding).

[0016] Beamforming Techniques Beamforming techniques include digital beamforming, analog beamforming, and hybrid beamforming. In digital beamforming, each antenna element may have a dedicated RF chain, including RF processing and ADC / DAC. The signals processed by each antenna element may be independently controlled in phase and amplitude to optimize channel capacity. The number of RF chains may be equal to the number of antenna elements. While offering extremely high performance, digital beamforming techniques may involve high cost, implementation complexity, and high energy consumption.

[0017] Analog beamforming may apply one RF chain for several antenna elements that make up a Phase Antenna Array (PAA). Each antenna element may use a phase shifter to set a phase-only weight for beamforming and steering of the antenna pattern of the PAA. The number of RF chains applied may be significantly lower than the number of antenna elements. The number of RF chains may be the same as or lower than the number of PAAs. For example, multiple PAAs may be connected to a single RF chain, and each PAA may have an antenna pattern for a specific azimuth and elevation coverage. The RF chain may be switched to one PAA at a time to use a single RF chain with multiple PAAs to provide wide coverage by using one beam in different directions and time instances.

[0018] Hybrid beamforming may combine digital precoding and analog beamforming. Analog beamforming may be performed on antenna elements of the PAAs connected to the RF chain. Digital precoding may be applied to the baseband signal for each RF chain and its associated PAA. A hybrid beamforming configuration may include several data streams, several RF chains, several PAAs, and several antenna elements. The PAAs connected to the RF chain may be represented by antenna ports uniquely identified by beamformed reference signals, which are specific to such antenna ports.

[0019] FIG. 1 is a graph 100 of an example UE 3D transmit beam pattern using a 4×4 uniform linear array.

[0020] 2 shows an example UE block diagram of a hybrid beamforming system 200 with two transmitters 202, 204 and two phased antennas 206, 208. It starts with digital precoding 210 in the BB processing block 212. The I(214, 218) and Q(216, 220) output signals pass through ADC blocks 222, 224 and radio frequency processing blocks 226, 228 and are transmitted via the phased antenna arrays 206, 208 for analog beamforming.

[0021] High implementation costs and high energy consumption for digital beamforming techniques may lead to implementation considerations for NR system design. 5G NR beamforming techniques may be based on hybrid beamforming with a number of 5G NR transceiver nodes significantly lower than the number of antenna elements. Analog beamforming techniques may have significant impacts on L1 / L23 system procedures and lead to new procedure behaviors and sequences. Beamformed transmissions may provide a high degree of flexibility to eNBs to customize transmissions in both the time and spatial domains to reduce signal overhead and energy consumption.

[0022] LTE / LTE-A Uplink Multi-Antenna Technique LTE and LTE-A allow multi-antenna techniques. In transmit antenna selection, open-loop antenna selection masks scrambling on uplink grant CRC bits. Closed-loop transmit antenna selection is configured by higher layers based on optional UE capability reporting. The Spatial Orthogonal Resource Transmit Diversity (SORTD) method is the same as UCI on different UE antennas using different orthogonal resources. In PUCCH, it uses dual antennas. In MU-MIMO, up to eight UEs on the same set of RBs each use single antenna transmission. Also, a 3-bit PUSCH cyclic shift and OCC for PUSCH DMRS provide orthogonality. The MU-MIMO method is transparent to the UE. In SU-MIMO, there is a precoder with CM preserving constraint (e.g., one layer per antenna). Also, the eNB selects the precoder based on the non-precoded SRS and signals the number of layers and PMI using DCI 4. The SU-MIMO method uses an SRS for each antenna port.

[0023] Control of uplink transmissions Wireless systems employ mechanisms to control transmissions from UEs (such as uplink or sidelink) to ensure proper link adaptation while preventing excessive interference to other UEs. Such mechanisms include transmit power control, timing alignment, and transmit parameter indicators, such as modulation, coding, and frequency allocation. In LTE, UEs equipped with multiple antenna elements may also be indicated by precoding weights to be applied for transmission. This mechanism may use the UE transmitting reference signals for every antenna element to determine the precoder that maximizes the quality at the receiver side. The use of such precoders may allow for a reduction in transmit power for a given transmission, and therefore, of course, reduce interference to the system. In LTE, the maximum number of reference signals (or antenna ports) for uplink transmission is four.

[0024] UE autonomous rotation and obstruction detection It is not uncommon for a UE to be equipped with a variety of motion sensors including an accelerometer, a gravity sensor, a gyroscope, a rotation vector sensor, etc. The accelerometer and gyroscope are hardware-based, and other software-based sensors can derive further motion data based on inputs received from the two hardware-based sensors.

[0025] The sensor data provides the UE with detailed detection information regarding the UE rotational movement. The rotational movement may be a reflection of direct user input, such as tilting, shaking, rolling or rocking the UE during video game play. The detected rotational data allows the UE to calculate the angular change in the orientation of its own antenna array. The orientation change may be indicated using the rate of rotation about the X / Y / Z axes and the respective vector components along each axis.

[0026] A motion sensor in the UE can collect data resulting from relative movement. The relative movement can provide a reflection of the physical environment in which the UE is located. For example, in some embodiments, the motion sensor can detect the approach of a stationary obstacle due to the movement of the UE, or the movement of a moving obstacle toward a stationary UE. In such embodiments, the motion sensor data enables the UE to detect an upcoming obstruction and estimate the translational motion vector of the obstruction, including its speed and direction relative to the UE.

[0027] In an exemplary embodiment, the advanced motion sensor may operate to distinguish between a human body and inert material. In such an embodiment, the UE is thus able to not only detect an approaching obstruction, but also to distinguish whether the obstruction is a human body or not. This feature may be used by the UE to comply with Specific Absorption Rate (SAR) regulations for handset devices.

[0028] beam The term "beam" may be used herein in several different contexts. A beam may be used to mean a set of precoding or cophasing weights applied to antenna elements in a user equipment (UE) or network equipment (e.g., a transmitting point or a receiving point) for transmission or reception. The term beam may also refer to an antenna pattern or radiation pattern resulting from the application of such precoding weights, or to at least one reference signal transmitted while applying a set of precoding weights to the antenna elements, at least one sequence used for the generation of at least one reference signal. There are other references to a set of properties associated with this antenna pattern, such as gain, directivity, beamwidth, beam direction (relative to a reference plane) in azimuth and elevation, peak to side lobe ratio, or to at least one antenna port associated with such antenna pattern. Additionally, the term beam may refer to an associated number and / or configuration of antenna elements (e.g., a uniform linear array, a uniform rectangular array, or other uniform array).

[0029] Beam Processing A beam class refers to beams that share at least one characteristic, such as beam width or beam solid angle. A higher beam class refers to a higher level of directivity and a lower beam class refers to a lower level of directivity. A beam family consists of all beams of the same beam class. A beam group is a set of beams that are associated with beams of a lower beam class. A beam may be associated with a beam of a lower beam class based on, for example, the beam with the closest central direction or the beam with the greatest overlap or correlation.

[0030] 3A and 3B are two graphs 300, 350 of beam amplitude versus direction 308, 316 showing the distinction between the beam center direction 304, 314 and the beam peak direction 306, 312. The beam direction is the direction of the beam which may be defined as the beam center direction 304, 314 or as the beam peak direction 306, 312. FIGS. 3A and 3B also show the EIRP peaks 302, 310 with black dots. A beam space is the area or solid angle covered by a set of beams, which may have any weight vector. A beam space may be bounded or defined by a set of parameters, such as a set of angles, or by the beams themselves.

[0031] In some exemplary embodiments, the UE may set precoding weights and other parameters for transmission and / or reception of signals, control and data according to at least one beam process. The UE may calculate or modify values ​​for such parameters and use these values ​​in subsequent transmissions or receptions that reference the beam process using, for example, beam process identification information. Such an exemplary process significantly reduces the overhead associated with determining precoding weights because it does not rely on continuous transmission of a reference signal and does not necessarily involve signaling of precoding for every transmission. Such an exemplary process also reduces implementation complexity for advanced transmission schemes, such as spatial multiplexing, beam diversity, or multipoint coordination through the use of two or more beam processes. A beam process may also be referred to as a beam pair link (BPL).

[0032] For transmission from the UE, the beam process may determine at least one set of precoding or cophasing weights to be applied to antenna elements. Such determinations may form a beam, where each such set may correspond to an antenna port. The transmit beam process may determine a timing advance for a downlink timing reference signal, or a transmit power level. For reception from the UE, the beam process may determine at least one set of precoding weights to be applied to antenna elements for reception. Again, such determinations may form a beam, where each such set may correspond to an antenna port. The beam process may also determine settings for an automatic gain controller (AGC).

[0033] In some exemplary embodiments, a bidirectional beam process may control both transmission and reception and may determine separate sets of precoding weights or beams for transmission and reception. Alternatively, the beam process may control only transmission (transmit, or UL, beam process) or only reception (receive, or DL, beam process).

[0034] The UE may determine that the beams used in reception and transmission should have the same or similar patterns in the receive beam process and the transmit beam process, respectively, or in the bidirectional beam process. Such a determination may be based on higher layer signaling, or the determination may be based implicitly on the frequency band or another property of the system to which the UE is accessing or to which the UE is connected. In such a case, the UE may derive the precoding weights used in transmission based on the precoding weights determined for reception, or vice versa. In the case of a transmit beam process and a receive beam process, such processes may then be referred to as being related by reciprocity. In the case of a bidirectional beam process, the processes may be referred to as being reciprocal.

[0035] In some embodiments, a default beam process may be defined. Such a default beam process may be applied for downlink or uplink transmissions in the absence of a specific configuration, or the default beam process may be determined from higher layer signaling. Such a default beam process may be predefined such that the maximum beam gain or directivity obtained is minimized, or the pattern is nearly omnidirectional.

[0036] Also, the use of the default beam process may be frequency band dependent, for example according to a pre-determined rule or higher layer signaling. For example, whether the PRACH transmission should use the default beam process may be indicated as part of the RACH configuration, which may be provided by the system information. Such signaling may be beneficial if the network uses synchronized transmissions from multiple TRPs for the transmission of signals used by the UE for system timing and path loss estimation.

[0037] The UE may maintain one beam for each beam process. Such a beam may be initially selected and updated as part of a beam selection procedure that determines the beam that results in the best propagation channel (e.g., by maximizing the received signal power for a given transmit power) for a given beam or antenna applied to another UE (e.g., a network node).

[0038] FIG. 4 illustrates an example embodiment of beam propagation in a system 400. At any given time, a UE 402 may be configured with multiple beam processes to support spatial diversity or multiplexing, multipoint operation, and mobility. This is illustrated in FIG. 4, where process 1 and process 2 correspond to the direct path 404 and the reflected path 406 to TRP1 (410), and process 3 corresponds to the path 408 to TRP2 (414). The reflected path 406 reflects off a building 412, and the direct paths 404, 408 are line of sight. Each configured beam process may be considered to correspond to a transmit or receive instance with a particular antenna pattern that maximizes the beamforming gain along the channel path. Multiple beam processes may also be used to support different levels of beamforming depending on the type of information being transmitted and the associated reliability requirements, or depending on whether the transmission is unicast or multicast.

[0039] The current beam refers to the latest result of the beam selection procedure. In a bidirectional process, the current beam may be applied to both transmit and receive. Alternatively, a separate current beam may be applied for transmit and receive. Similarly, the beam selection procedure may select a separate beam for each antenna port, resulting in a current beam for each antenna port.

[0040] In some exemplary embodiments, when a beam process is applied to transmit or receive, the applied beam corresponds to the current beam. In some exemplary embodiments, the UE 402 may maintain the beam selected in a previous beam selection procedure. For example, the UE 402 may maintain the most recently selected beam of a beam class only if such beam class (or beam gain) is lower than the beam class (or beam gain) of the current beam. When maintaining multiple beams for a beam process, each beam may be associated with a beam identification that may correspond to a beam class.

[0041] Some beam selection procedures may be based on performing a series of measurements taken from a downlink reference signal. Such a reference signal is referred to herein as a beam selection reference signal. In some embodiments, the UE 402 may adjust the AGC settings based on such a beam selection reference signal. A beam process may be provisioned with resources for at least one such beam selection reference signal. The resources for provisioning the beam process reference signal may include at least one identity parameter and an indication of time and frequency resources used to generate the sequence. In some exemplary embodiments, the identity parameter may be specific to the beam process.

[0042] Some exemplary beam selection procedures may be based on performing at least one transmission of an uplink (or sounding) reference signal, referred to as a beam sounding reference signal. A beam process may be provisioned with resources for at least one such beam sounding reference signal. The resources for provisioning the beam sounding reference signal may include at least one identity parameter used to generate the sequence as well as an indication of time and frequency resources. In some exemplary embodiments, the identity parameter may be specific to the beam process. Also, the identity parameter for the uplink may be the same as the identity parameter used to generate the beam selection reference signal.

[0043] In some exemplary embodiments, resources for beam selection reference signals and beam sounding reference signals may be dynamically allocated. Furthermore, these reference signals may be allocated on a subset of available time and frequency resources. Such allocation may be done to avoid continuous broadcasting of signals and to reduce high overhead costs. For example, downlink control information (such as random access response or signaling that triggers beam selection procedures), or a combination of downlink control information and higher layer signaling, may indicate resource allocation.

[0044] The beam selection reference signal may be associated with a set of parameters used for spreading or scrambling, which may include, for example, a spreading factor, a spreading sequence, such as an OVSF code and a Walsh code index, and a scrambling sequence index.

[0045] As described below, various resources may be associated with a beam process for data transmission / reception.

[0046] A beam process for data transmission / reception may be associated with time domain resources, including, for example, time units, symbols, subframes, slots, and blocks of frames. A beam process may also be associated with a set of frequency domain resources, including, for example, subcarriers, blocks of subcarriers, resource blocks, sets of resource blocks, and wideband carriers. A beam process may be associated with code domain resources, including, for example, the type of spreading and / or scrambling code (OVSF / Walsh / ZC code), the spreading / scrambling length, and the index of the spreading / scrambling sequence.

[0047] The time / frequency / code resources associated with a beam process may be static and pre-configured for a certain type of beam process. For example, resources associated with a beam process used for a cell-specific common control channel in some embodiments may be fixed and broadcast in a system information broadcast transmission. In other embodiments, such beam processes may have fixed and pre-defined resource allocations. Beam processes for both data transmission and data reception may also be associated with resources that dynamically use downlink control information in physical layer control signaling. In another embodiment, resource association information per beam process may be carried in higher layer signaling, such as RRC signaling.

[0048] The association of beam processes with resource allocation may enable flexible configuration and reduced signaling overhead for beam processes connected to multiple TRPs or used for hierarchical control channels for downlink / uplink / sidelink.

[0049] The UE 402 may be configured to maintain two or more beam processes (such as bidirectional or unidirectional processes) (see FIG. 4). Each such beam process may correspond to reception or transmission for a particular antenna pattern, such that the patterns of the different beam processes maximize antenna gain in different directions. Thus, for each beam process, the UE 402 may maintain precoding weights, Tx power, and timing. Each beam process may be associated with a different network transmission point, e.g., a TRP. Connection with multiple TRPs may enable support for multipoint operation, diversity, seamless mobility, and fallback operation. Maintenance of two or more such beam processes may enable transmission and / or reception to and / or from multiple points, or to a single point using different beams.

[0050] A beam process may be configured with a beam process identification for referencing purposes. A particular beam process may be designated as a primary beam process or a master beam process. If the UE 402 maintains only one beam process, such a beam process may be designated as a primary (or master) beam process. If the UE 402 maintains more than one beam process, the UE 402 may receive signaling to designate a primary beam process.

[0051] Control Channel Monitoring In some exemplary embodiments, the UE 402 may determine at least one beam process for decoding a downlink control channel, such as a physical downlink control channel or a physical broadcast channel. When attempting to decode the downlink control channel, the UE 402 may use the precoding weights determined by the beam process for reception.

[0052] In one embodiment, the beaming process is associated with at least one control channel configuration from which the UE 402 determines resources on which it should attempt to decode downlink control information. The configuration may include at least one of the following: - At least one control resource set, control subband, or control time symbol within a scheduling unit such as a slot, minislot, or subframe. - at least one parameter used to derive at least one search space (or set of candidates) for an instance of a control channel within at least one control resource set. o At least one search space may be defined with respect to at least a subset of control channel elements, resource element groups, sets of time symbols and / or physical resource blocks within a control resource set. At least one beam process may be associated with a common search space. At least one parameter used to determine a subset of possible scheduling units (e.g., slots) in which downlink control information transmitted using the beaming process may reside, such as a duration and offset in units of slots (or minislots). In some embodiments, there may be two or more configured such subsets that may be selected based on an activity state or priority associated with the beaming process. - at least one parameter used to determine at least one property of a reference signal, such as a sequence, used for the purposes of decoding at least the control channel;

[0053] The configuration may be obtained from RRC signaling, such as dedicated signaling and / or system information from at least a physical broadcast channel.

[0054] Independent configurations and example usage scenarios Each beam process may be configured with or associated with an independent control channel configuration for maximum flexibility. For example, control subbands or resource sets may be configured differently between different beam processes, which may be useful in scenarios where they are associated with geographically separated TRPs that use different resources for the control channel to better coordinate interference.

[0055] In another example, the time symbols within a slot may be configured differently, which may be useful in scenarios where uplink and downlink data transmissions involve different TRPs (e.g., hetnet scenarios with low and high transmit power TRPs). In such scenarios, a downlink assignment may be received from a first TRP using a first beam process, and an uplink grant may be received from a second TRP using a second beam process.

[0056] In some embodiments, to reduce signaling overhead, at least one parameter of the control channel configuration may be common to all beam processes.

[0057] Prioritization between beam processes In some situations, there may be overlap between resources used by different beam processes, such that reception using at least one such beam process is not feasible. For example, this may occur when the UE 402 is only capable of receiving using at most N beam processes at a given time (where N may correspond, for example, to the number of RF chains in the UE receiver implementation), and there is an overlap in the time domain between the control channel candidates of more than N beam processes in a given slot. In another example, the control channel candidates for a first beam process may overlap with the scheduled transmissions for a second beam process. When such a situation occurs, the UE 402 may apply prioritization rules between the beam processes based on at least one of the following criteria: - A configured priority associated with each beam process. For example, the UE 402 may prioritize reception of the control channel for a primary beam process or based on an index associated with the beam process (e.g., a lower index has a higher priority). - An activity state associated with each beam process. For example, a beam process in an "active" state may be prioritized over a beam process in an "inactive" state, or a beam process in an "inactive" state may be prioritized to provide a fallback mechanism if the quality for a beam process in an active state is degraded. - The periodicity for a subset of scheduling units when the control channel is monitored for a beam process. For example, priority may be given to the beam process with the greatest periodicity. - The latest reported channel condition indication for each beam process. For example, priority may be given to the beam process with the highest channel quality indication. - The type of transmission associated with the beam process. For example, a scheduled transmission for a first beam process may have priority over a control channel candidate for a second beam process. In another example, such a scheduled transmission may have been scheduled in a previous slot and may overlap with the control resource set of the current slot.

[0058] To handle instances where one rule does not allow for granularity, multiple rules may be used. For example, the UE 402 may first prioritize based on activity state, and if two or more processes have the same activity state, a rule based on the configured priority may be used. Alternatively, other conditional ordering of rules may be utilized.

[0059] Relationship with antenna port In some exemplary embodiments, a fixed or semi-static association between a beam process and an antenna port or set of antenna ports may be established. Whenever the UE 402 is configured to transmit or receive on an antenna port, it applies a precoding weight of the corresponding beam process. The set of antenna port(s) associated with a beam process may be quasi-colocated in space with each other. For example, if an association is defined between an antenna port on which a demodulation reference is transmitted and an antenna port on which a reference signal used for beam selection (such as CSI-RS or beam selection RS) is transmitted for a beam process, the association may indicate that such antenna port is quasi-colocated in space. Thus, an implicit or explicit indication of a beam process for reception using an antenna port may be equivalent to an indication that this antenna port is quasi-colocated in space with a beam process or a reference signal (e.g., CSI-RS) of a beam pair link. Alternatively, in some exemplary embodiments, the association between a beam process and an antenna port may be dynamically modified. The UE 402 may determine an applicable beam process for transmitting or receiving on an antenna port.

[0060] In one exemplary embodiment, the applicable beam process may be determined from an explicit indication received from physical layer signaling or higher layer signaling. For example, the UE 402 may receive downlink control information (DCI) indicating an uplink (or sidelink) transmission (grant) on an uplink (or sidelink) physical channel, where such grant may include an indication of an applicable beam process for transmission on each antenna port. Such beam process may be different from the beam process used to receive the DCI. In another exemplary embodiment, the UE 402 may receive downlink control information indicating a downlink assignment for reception from a downlink physical channel, where such assignment may include an indication of an applicable beam process for reception on each antenna port. In yet another exemplary embodiment, the UE 402 may receive a MAC control element or an RRC message indicating an applicable beam process for transmission or reception on each antenna port for subsequent transmission or reception on an uplink physical channel, a sidelink physical channel, or a downlink physical channel.

[0061] In another exemplary embodiment, the applicable beam process may be implicitly determined based on the beam process used to decode the associated transmission. For example, the applicable beam process for a downlink transmission may correspond to the beam process used to decode the DCI indicative of this downlink transmission from a downlink physical control channel. In some cases, the downlink transmission may be a downlink physical data channel, a second downlink physical control channel, or a downlink signal such as DM-RS or CSI-RS. In another example, the applicable beam process for an uplink transmission (e.g., an uplink physical channel or signal) may correspond to the beam process used to decode the DCI indicative of or triggering this uplink transmission. In particular, the applicable beam process for an uplink control channel containing HARQ-ACK feedback associated with a downlink data transmission may correspond to the beam process used to decode the DCI indicative of this downlink data transmission, and / or the applicable beam process for an uplink control (or data) channel containing a CSI report may correspond to the beam process used to decode the DCI indicative of the transmission of the reference signal(s) from which the report is derived, e.g., CSI-RS. In another example, the applicable beam process for the uplink control channel containing the HARQ-ACK for the downlink transmission may correspond to the beam process used to decode the downlink transmission. In another example, the applicable beam process for the random access response may correspond to the beam process used to transmit the random access preamble.

[0062] In the above examples, the correspondence between the beam processes can be that both processes are equivalent (e.g., for a bidirectional beam process) or that both beam processes are related by reciprocity.

[0063] Alternatively, in some embodiments, the correspondence may be configured by physical layer signaling or higher layer signaling. For example, the applicable beam process for UL data transmission when a certain beam process is used to decode the DCI indicating this transmission may be configured by RRC signaling. Such an embodiment may enable transmission and reception from different network TRPs, which may be advantageous in heterogeneous deployments where the best node for downlink transmission may be a high power TRP and the best node for uplink transmission may be a (closer) low power TRP. In another example, the applicable beam process for the random access response may be configured to correspond to a default beam process (e.g., an omni-directional beam is so configured as part of the RACH configuration). Such a configuration may enable synchronized transmission of random access responses from multiple TRPs.

[0064] In another example, the correspondence may be obtained more dynamically, such as by MAC signaling or physical layer signaling. Such an embodiment may enable the use of different beam processes (e.g., with beams in different directions) for control or data reception on the one hand and data transmission on the other hand. This may be beneficial if the configured maximum transmit power for one beam process is lower than that for another beam process, such that the best beam process for downlink reception is not the beam that allows the best performance for uplink transmission. Such a situation may arise, for example, due to SAR requirements that affect some beam processes more than others. In such a case, for example, the UE 402 may inform the network of the different configured maximum transmit powers by transmission of a power headroom report(s) triggered by a change in the power management maximum power reduction (P-MPR) for at least one beam process.

[0065] In another embodiment, the applicable beam process may be implicitly determined based on the time and / or frequency resources occupied by the transmission. The correspondence between resources and beam processes may be provided by higher layer signaling.

[0066] In another exemplary embodiment, the applicable beam process may be determined based on the physical channel or signal type over which transmission or reception is taking place.

[0067] In another example embodiment, the applicable beam process may be determined based on the type and / or content of the transmission, such as whether the transmission consists of control information (e.g., uplink or sidelink) or higher layer data, or whether the transmission is multicast or unicast (e.g., for sidelink transmissions). For example, a transmission of a scheduling request may be performed using a particular beam process, such as a primary beam process.

[0068] When maintaining multiple beams for a beam process, embodiments similar to those described above may be used to determine which beam identity applies to a particular transmission. In some embodiments, the sequence used for generation of the demodulation reference signal may be specific to the beam process. Such a sequence may be generated using identity parameters that match identity parameters used for generation of sequences for the beam selection reference signal or the beam sounding reference signal.

[0069] Beam compatibility decision In some embodiments, the UE 402 may determine, for at least one pair of transmit and receive beams, a correspondence between a beam used for transmission (transmit beam or uplink beam) and a beam used for reception (receive beam or downlink beam). If such correspondence is determined, the UE 402 may determine that a transmit beam used for a first transmission from the UE 402 is a transmit beam that corresponds to a receive beam used to receive a second transmission. Such a receive beam may correspond to a receive beam that maximizes signal strength or quality when used to receive a second transmission. The following paragraphs describe such embodiments.

[0070] Predetermined or static beam support In one embodiment, beam correspondence may be pre-determined for at least a subset of all transmit and receive beams according to a mapping stored in a memory. The mapping may be performed as part of a calibration or test procedure. The mapping may be such that the difference in the radiation pattern (or its properties, such as the direction in which the gain is maximized) between a transmit beam and its corresponding receive beam is minimized. The mapping may also be such that the precoding weights used for the transmit and receive beams have equivalent or approximately the same values.

[0071] Dynamic beam support state In some embodiments, beam correspondence between transmit and receive beams may not exist consistently due to implementation conditions (e.g., differences between TX and RX RF paths) and / or operating conditions (e.g., temperature changes, reference clock phase drift) such that the determination of beam correspondence is dynamic.

[0072] The dynamic beam capability state may be indicated in-state and out-of-state. The beam capability state may be specific to an individual beam, beam type, beam class, beam group, or antenna panel, or to a set of beams, beam types, beam classes, beam groups, or antenna panels. The UE 402 may be configured with a beam capability update period and may evaluate and update the beam capability periodically according to the update configuration. The UE 402 may perform a beam capability state update in response to receiving L1 control signaling or higher layer (MAC, RRC) signaling from the network. In another embodiment, the UE 402 may trigger a beam capability update upon a predefined event, which may include one or more of the following procedures: - Add a new beam, beam type, beam class, beam group, or reconfigure the antenna panel; during or at the end of the RACH procedure, for example by incorporating an update procedure step in the Msg1 and / or Msg3 transmissions, or - Configuration of UL beam management procedures. The network may determine whether UL beam management may be configured depending on the beam capability state. The network may not configure any such procedures, e.g., U1, U2, or U3, if the beam capability state is in state.

[0073] In one embodiment, the UE 402 may update the beam correspondence state by evaluating the transmit beam radiation pattern and the corresponding receive beam radiation pattern and comparing / correlating the pattern parameters such as peak lobe direction, 3 dB main lobe width, side lobe direction, side lobe width, side lobe suppression ratio, etc. The comparison and evaluation criteria may be predefined.

[0074] In another embodiment, the UE 402 may update the beam support using a beam support update procedure. In one embodiment, the UE 402 may perform the following acts: - transmitting a beam-specific reference signal, e.g., SRS, using uplink beam sweeping based on a set of uplink transmit beams; - monitoring downlink control information in all receive beams corresponding to an uplink transmit beam, where the downlink control information may include a best uplink transmit beam identification, e.g., a beam index or an SRS resource indication (SRI); - receiving downlink control information in one or more receiving beams (e.g., when the UE 402 is located in the middle of two downlink beams) and verifying whether the best receiving beam may correspond to the uplink transmission beam identification information received in the downlink control information; - if the verification result is a match, determining to be in the beam-compatible state, and if the verification result is not a match, determining to be out of the beam-compatible state; - Reporting beam-capable status using uplink control signaling.

[0075] In another embodiment, the UE 402 may perform the following actions: - Using a beam-specific reference signal, e.g., transmitting in a first transmission via an SRS in an uplink beam corresponding to a best downlink beam (e.g., based on an SS block), where the SRS resource / sequence may carry an indication of the best SS block; - transmitting the second transmission using uplink beam sweeping based on a set of uplink transmit beams with beam-specific reference signals, e.g., SRS, including those used in the first transmission; - Receiving a beam-capable in-state or out-of-state indication in downlink L1 control signaling by the network.

[0076] In this embodiment, the network may determine the beam compatibility status by verifying whether the first SRS is the same as the best SRS received in the second transmission. Note that the network may use the receive beam corresponding to the indicated best SS block in both the first and second UE transmissions.

[0077] The UE 402 may be configured to perform UL beam management procedures (U1 / U2 / U3) when the UE beam capability state is out of state. In this embodiment, the UE 402 may be configured with an explicit association between uplink and downlink beams.

[0078] The UE 402 may receive an instruction in L1 control signaling or higher layer dedicated signaling to select an uplink beam based on a downlink beam without a UL beam management procedure when the UE beam capable state is in the state. In this embodiment, the UE 402 may maintain an implicit uplink and downlink beam association.

[0079] In another embodiment, the UE 402 may determine the beam correspondence based on an indication from the network. Such an embodiment may be applicable, for example, when the beam correspondence already exists on the network side. The UE 402 may first transmit a sequence of beam-specific reference signals (e.g., SRS) for at least one beam (e.g., beam sweep). Such transmission may be triggered by signaling from the network at the physical layer or higher layer. The UE 402 may then receive an indication of the transmit beam, for example, using an SRS indicator, together with an indication of the CSI-RS (or CSI-RS indicator) corresponding to a certain downlink transmit beam. Such an indication may be included in the same instance of physical layer signaling (downlink control information), MAC signaling (MAC control element), or RRC message. The indication may be combined with an indication that the CSI-RS is transmitted at a certain time. Upon receiving the indicated CSI-RS, the UE 402 may determine the receive beam that maximizes the signal quality. The UE 402 may determine that there is a beam correspondence between this receive beam and the transmit beam used for transmitting the SRS indicated by the network.

[0080] Power Control - Open Loop Components In some exemplary embodiments, the transmit power may depend on the beam process applicable to the transmission.

[0081] The transmit power may be a function of a path loss measurement taken on a downlink reference signal. Such a downlink reference signal may be referred to as a beam path loss reference signal. Resources for such a beam path loss reference signal may be allocated independently for each beam process. In some exemplary embodiments, the beam path loss reference signal may coincide with the beam selection reference signal. The path loss measurement PL may be a function of the reference transmit power P ref and the received signal power P r It may be defined as the difference (in dB) between

[0082] The beam used for the measurement may be at least a receive beam for a reciprocal bidirectional beam process or may correspond to a receive beam process related by reciprocity to a transmit beam process. Alternatively, the beam used for the measurement may be a predefined beam, such as an omnidirectional beam or a default beam. Alternatively, the UE may select a receive beam or beam process that minimizes an estimated path loss or maximizes a received signal.

[0083] Alternatively, the receive beam used for path loss measurement may be determined from signaling. For example, the receive beam or whether the UE 402 should use a default beam process or select a beam process may be signaled from system information. Such an embodiment may be used, for example, to determine a path loss estimate and transmit power for a PRACH transmission.

[0084] In some exemplary embodiments, the path loss measurement is based on the gain or directivity G of the beam used to take the measurement. b As expressed as a formula, the path loss measurement PL may be calculated as follows: PL=P ref -P r +G b , In the above formula, P ref and P r can be in dBm, and PL and G b may be in dB. This adjustment may allow for appropriate compensation of differences in gain (or directivity) between the beam used to take the path loss measurement and the beam used in the subsequent transmission. In this latter case, the gain G b The transmit power for the beam with ' is (PL-G b '), where PL and G b In some embodiments, the path loss measurement PL may not be adjusted, and (P ref -P r ), but the transmit power can be equal to PL+Gb -G r can be set as a function of

[0085] Power Control - Closed Loop Components The UE 402 may receive signaling (transmit power control (TPC) commands) to perform adjustments of the power applied to some transmissions. Such adjustments may be cumulative (applied to all subsequent transmissions to which a particular beam process is applied) per beam process. The beam process may be explicitly identified with the TPC command or may be implicitly based on the beam process corresponding to the transmission to which the TPC command is applied. Also, adjustment step values ​​may be independently configured for each beam process.

[0086] Power Control - Configured Maximum Power (P cmax ) In some embodiments, the UE 402 determines a configured maximum power (e.g., P-MPR) for each beam process based on at least a maximum power reduction parameter (e.g., MPR, A-MPR, or P-MPR). cmax ) may be applied, where P cmax and maximum power reduction parameters may differ between beam processes. For example, this may result from beam-specific power management MPR (P-MPR) values ​​from the Specific Absorption Rate (SAR).

[0087] Maximum configured gain or maximum configured EIRP In some embodiments, the UE 402 may operate to limit the gain of a beam to a maximum possible gain given the antenna configuration. Such a situation may arise, for example, when the UE 402 is operating to meet specific absorption rate requirements.

[0088] The configuration parameters are e.g. EIRP, maximum gain (G max) and maximum directivity. The parameters may be based on the UE 402 capability report regarding the UE antenna array beamforming configuration and capabilities. The eNB may configure the parameters using higher layer signaling. In another solution, the UE 402 may autonomously set the maximum gain or directivity.

[0089] The UE402 uses P cmax Both the G and max gain parameters can be used to maximize the EIRP. max The parameters may be influenced by the physical channel associated with the beam process. For example, a beam process for uplink control information (UCI) transmission in a physical layer uplink control channel may be associated with a lower G max Therefore, the UE may transmit UCI in a beam process with a wide beam width. An advantage may be to increase the reliability and robustness of the UCI transmission.

[0090] The UE may report the offset between the actively applied beamforming gain and the configured maximum gain for each beam process. The difference may be caused by, for example, the MPR caused by the SAR. The eNB may report the offset between the actively applied beamforming gain and the configured maximum gain for each beam process. max The eNB may receive the offset and trigger an uplink beam reselection procedure for the associated beam process. Such an embodiment may enable the eNB to flexibly adjust uplink reception based on the beam width and beamforming gain used for the beam process.

[0091] Power allocation for simultaneous beam processes connected to different TRPs The UE 402 may associate with a different TRP in the mobility event and add to it the beam process to be transmitted. The association may include uplink beam power control information specific to the new TRP. The UE 402 may receive the power control configuration parameters of the new TRP, including the uplink SINR target and the TRP reference signal power. The UE 402 may also receive the configuration of the new TRP for waveform and numerology and derive the required initial power and power step accordingly.

[0092] The UE may provide the new TRP with calculated power headroom information for the associated beam process. The calculation may take into account the transmission of all simultaneous transmissions of all active beam processes maintained by the UE 402. Thus, the power headroom may include fields for the beam process identification information and its corresponding power headroom value.

[0093] In embodiments in which the TRPs are synchronized, the transmissions may be code multiplexed on the same frequency resources.

[0094] In another embodiment, the UE 402 may be configured with a gap on one TRP link when the TRP is not synchronized or deployed on inter-frequency or inter-band to enable and maximize power transmission capability, which may be useful during mobility events in a non-synchronized TRP (e.g., in the case of FDD).

[0095] The gaps may be configured by the network upon a UE signaling event, for example, based on the quality of the current link(s). These gap patterns may have different lengths and finite durations with the goal of making the UE 402 report measurements, and the network may then decide which TRP to use and send a configuration message or an indication that the UE may start monitoring some control channels on some TRPs for scheduling, or an indication about the UL transmission start point with appropriate parameters.

[0096] The UE 402 may not rely on the configured gap if it has the capability of more than one transceiver chain. In this particular case, synchronous or asynchronous reception / transmission may be available, and the network signaling is reduced to a target TRP measurement indication indicating the target TRP(s) after receiving a measurement report from the UE 402. The target TRP measurement configuration may be a triggered message based on a quality threshold of the report triggered by the UE 402. In this situation, the output power may be adjusted to the desired level for carrier aggregation or dual connectivity P. cmax In a manner similar to the definition, power is shared between these UL transmissions. However, if a deployment-specific situation occurs where power sharing would not result in good results, the network may configure a gap on the serving TRP to allow a simultaneous connection with the target TRP. In this case, the gap decision may be based on reported measurements from the UE 402, where the path loss estimate may indicate possible scaling on the target TRP UL while maintaining the serving TRP.

[0097] Transmit timing for beam processing In some exemplary embodiments, the timing of a transmission may depend on the applicable beam process. The UE 402 may determine the timing of a transmission based on the timing of a downlink received signal, sometimes referred to as a beam timing reference signal. Resources for such a beam timing reference signal may be provisioned independently for each beam process. In some exemplary embodiments, the beam timing reference signal may be equivalent to a beam selection reference signal.

[0098] The UE 402 may determine the timing of a transmission based on a timing advance or adjustment to be applied from the timing of the beam timing reference signal. Such a timing advance or adjustment may be received from physical layer signaling, MAC signaling, or RRC signaling, such as a timing adjustment command. The timing adjustment may be beam process specific and applied to all subsequent transmissions to which a particular beam process is applied. The beam process may be explicitly identified with the timing adjustment command or may be implicitly based on the beam process corresponding to the transmission to which the timing adjustment command is applied.

[0099] In some demonstrative embodiments, a time alignment timer may be configured for each beam process, possibly with a value specific to that beam process. The time alignment timer for a beam process may be restarted each time a timing adjustment command is received for that beam process. The UE 402 may be enabled to perform transmissions according to a beam process only if the time alignment timer for that beam process is running (not expired).

[0100] Quasi-collocation assumptions In some demonstrative embodiments, a UE 402 receiving a downlink physical channel using a beaming process may assume that an antenna port on which a reference signal associated with the beaming process is transmitted is quasi-co-located with the antenna port(s) on which the downlink physical channel is transmitted, for at least one long-term channel property (such as timing, delay spread, or Doppler spread). Such a reference signal may correspond to a beam selection reference signal associated with the beaming process.

[0101] Channel state information for each beam process In some exemplary embodiments, the UE 402 may report channel state information per beam process. The UE 402 may perform measurements on at least one channel state information reference signal (CSI-RS) and at least one interference measurement (IM) resource. Resources for such signals may be provisioned independently for each beam process. The measurements may be performed using a current beam of a particular beam process. Physical layer signaling, such as an instance of downlink control information, may identify the beam process and possibly the current beam. Such downlink control information may include any of the following information: a request to perform CSI measurements, a request to report measured CSI, an allocation of resources for CSI-RS, or an allocation of resources for interference measurements.

[0102] Beam process synchronization state In some demonstrative embodiments, a synchronization state may be associated with a beam process. The UE 402 may determine that a beam process is in a "synchronized" state if a synchronization timer is running and / or the most recent beam selection procedure was successfully completed. The synchronization timer may be restarted upon successful completion of a beam selection procedure for a beam process resulting in at least one current beam. The duration of such a timer may be predefined or configured by higher layers or per process. If the UE 402 detects that a beam selection procedure has started and failed, the UE may stop the synchronization timer.

[0103] If the UE 402 measures a signal above level or quality for at least one beam, or if the UE 402 receives an indication from the network that the beam sounding reference signal was successfully received, the UE 402 may determine that the beam selection procedure was successful. The UE 402 may be allowed to perform transmissions using the beam process only if the beam process is in a "synchronized" state or while an applicable synchronization timer is running.

[0104] Beam Processing Procedures Beam Creation Procedure The procedures described in the following paragraphs may be used to create an initial (or primary) beam process and / or synchronize an initial beam process, create additional beam processes, or delete beam processes.

[0105] The UE 402 may initially have no beam process or may have a default beam process that is not synchronized. Such a situation may occur, for example, before initially accessing the system or after determining that the beam process is not synchronized. The creation of the initial beam process (or synchronization of the default beam process) may occur as part of the initial system access.

[0106] In an example embodiment, the UE 402 may initiate a random access procedure based on measurements taken on the signature sequence and / or mobility reference signal, as well as based on a random access configuration that may be broadcast. The UE 402 may randomly select a signal, such as a preamble from a preamble group. In some example embodiments, the preamble group may depend on the beamforming capabilities of the UE 402. The transmission of such a preamble may use a default beam, such as an extremely wide beam or a nearly omnidirectional beam. Alternatively, the transmission of the preamble may use a beam if the UE 402 can determine one for measurements taken on available signals.

[0107] The UE 402 may receive at least one random access response and possibly attempt to retransmit the preamble at a higher power level if such reception does not occur within a time window. The UE 402 may eventually decode the at least one random access response and select one such response. Each such response may include at least a configuration and resources applicable to a beam process. Such a response includes at least one of the following items: resources for a beam selection reference signal, resources for a beam sounding reference signal, timing advance adjustment, beam process identification information, and at least one parameter for power control (such as a reference transmit power). If a parameter for power control is not provided, this parameter may use a value broadcasted as part of the random access configuration.

[0108] The random access response may include other information elements used for the first transmission on the uplink physical channel. Resources for beam selection reference signals may occupy several symbols occurring after a time offset following the random access response. Such random access responses may be predefined or signaled in the random access response. The UE may measure such resources to determine the best beam (or current beam) for reception. If the UE receives more than one random access response, the UE 402 may measure on two or more corresponding beam sounding reference signal resources and select which random access response to follow for a subsequent transmission based on at least the measured signal quality or level of all responses.

[0109] The UE 402 may use the current beam (for the beam selection reference signal of the selected random access response) for transmission on the beam sounding reference signal resource. Such resources may generally occupy several symbols occurring after a time offset following the last symbol used for the beam selection reference signal resource. The transmission on the beam sounding reference signal resource allows the network to determine the best beam at the transmission / reception point (TRP). In some exemplary embodiments, the UE 402 may proceed with the procedure if it receives an indication from the network following the transmission of the beam sounding reference signal that the reception was successful. Subsequent transmissions and receptions on the uplink and downlink physical channels may use the current beam determined from the measurement of the beam selection reference signal. Further refinement of the current beam may then be initiated by the network.

[0110] In some exemplary embodiments, the UE 402 may utilize at least one parameter provided for the beam selection reference signal resource and the beam sounding reference signal resource for generation of the demodulation reference signal in the uplink and downlink. For example, such a parameter may consist of an identity parameter used to determine the sequence.

[0111] In some exemplary embodiments, the UE 402 may receive an indication for the creation of a new beam process from physical (or higher) layer signaling. The indication itself may be received using an existing beam process. For example, such an indication may consist of downlink control signaling triggering a random access procedure. Resources for the new beam process may be provided in a subsequent random access response as in other exemplary embodiments. Alternatively, the indication may directly allocate resources for the new beam process and directly trigger reception and transmission on the beam selection reference signal and the beam sounding reference signal, respectively. In such a case, the applicable timing advance may be the same as the existing beam process used to receive the indication.

[0112] In some exemplary embodiments, the UE 402 may receive an indication from physical (or higher) layer signaling for removal of an existing beam process. The UE 402 may perform measurements for the beam process. Such measurements may enable the UE 402 to identify the best beam in the beam process. For example, the UE 402 may be configured to use a beam (current beam) in a beam process configuration. The UE 402 may perform measurements using that beam along with a subset of other beams (possibly beams in a beam group defined later). Such measurements may be periodic and configured by the network. In another exemplary embodiment, such measurements may be aperiodic. For example, the UE 402 may be triggered to perform such measurements by its serving TRP, possibly via a transmission using that beam process. In another example, the UE may be triggered to perform such measurements on a beam group by measurements performed on beams associated with the beam process.

[0113] Upon taking such measurements, the UE 402 may determine that a new beam would improve reception (and possibly transmission) from / to the TRP / cell / eNB. In such a case, the UE 402 may autonomously update the beam process to include the new beam. The UE 402 may also indicate to the network (e.g., via a transmission using the beam process itself) that the UE 402 has changed its beam. This may allow the network to determine whether its own beam is still best suited for the new UE beam. In another example embodiment, upon determining that a new beam may improve the performance of the beam process, the UE 402 may request the network to initiate a new beam selection procedure. Such a process may or may not require the UE 402 to use the newly determined beam.

[0114] Mobility-related aspects Upon triggering measurements on a set of beams (beams in a beam group), the UE 402 may not find a suitable beam to use in the beam process. For example, the UE 402 may initiate a tuning process with measurements on an original beam process configuration indicating that it cannot successfully transmit and / or receive data using the beam process. Such a conclusion may be based on the measurements being less than a threshold. In this case, the UE 402 may be instructed to find another beam to use in the beam process before continuing to use the beam process. If the UE 402 fails to acquire another beam in the beam group, it may take at least one of the following actions: continue to search for a beam in another beam group or possibly in the same beam class, continue to search for a beam in another beam class or a beam class that overlaps with the previously selected beam, or declare a Radio Link Failure (RLF) or Beam Link Failure (BLF) for the beam process. Wherever RLF is used herein, it also includes BLF.

[0115] If the UE 402 has determined the RLF for a beam process, it may indicate such a situation to at least one serving TRP. If the UE 402 is still configured with an operational (e.g., non-RLF) beam process, the UE 402 may indicate the identity of the RLFed beam process to the TRP. In one embodiment, the UE 402 may transmit an uplink beam recovery transmission to convey an indication. Moreover, in the beam recovery transmission, the UE 402 may request a switch to a target beam process, e.g., an operational (e.g., non-RLF) beam process, to maintain the UE radio link. The UE 402 may use pre-configured time / frequency / code / beam resources for the beam recovery transmission. For example, the UE 402 may use an uplink transmission beam associated with an operational (e.g., non-RLF) beam process. In another example, the UE 402 may transmit a beam recovery transmission on a default UL beam. The beam recovery transmission may be repeated over multiple symbols, slots, or transmissions to enable beam sweeping at the receiver. In another example, the UE 402 may transmit a beam recovery transmission in the manner of uplink beam sweeping using uplink beams associated with all configured beam processes. The UE 402 may monitor and receive a switch command in downlink L1 control signaling. The switch command may be received by the UE 402 on a default beam pair link (e.g., a wide beam Tx and Rx beam pair, which may be omnidirectional). The switch command may indicate resources on which the UE 402 may perform beam acquisition. In another embodiment, the switch command may explicitly indicate to the UE 402 one or more BPLs to use for the next transmission. In another embodiment, the UE 402 may monitor and receive a switch command in downlink L1 control signaling for a downlink beam associated with a target beam switching process.

[0116] If the UE no longer has any operational beam process (e.g., the UE is configured with a single beam process and that beam process has experienced an RLF), the UE may perform a new initial beam process acquisition. In another example embodiment, the UE may be configured with a master beam process or a primary beam process. Declaration of an RLF on such a beam process may trigger the UE to perform a new initial beam process acquisition. Such a process may remove all existing beam processes. During such a process, the UE 402 may indicate to the network whether an RLF has occurred on one (e.g., master or primary) beam process or on all beam processes (e.g., on all beam processes associated with that TRP / cell / eNB).

[0117] In an example embodiment, the initial beam process acquisition may use a random access procedure. In such a case, the UE 402 may be pre-configured with resources and / or preamble values ​​to perform non-contention based RA for beam process (re)acquisition. In another example, the UE may have connectivity to a second TRP / cell / eNB. The second TRP / cell / eNB may provide the UE with random access resources (or preambles) to perform non-contention based random access, possibly upon declaring RLF on one or all beam processes of the first TRP / cell / eNB.

[0118] The UE 402 may maintain measurements on at least one mobility reference signal (MRS). Such mobility reference signals may be transmitted per TRP or on orthogonal resources for each TRP. Mobility measurements may use a specific beam process (such as a beam process dedicated to such measurements). The UE 402 may decide to add a new beam process. Such a decision may be triggered by measurements on at least one MRS indicating the possibility of acquiring one or more new beam processes, a decision by the UE 402 to improve reception or transmission performance, the location of the UE, or an RLF on one or more beam processes associated with the TRP / cell / eNB. The UE 402 may improve reception or transmission performance via increased diversity with the addition of a new beam process. In another example embodiment, the UE 402 may request a new beam process to enable CoMP-like transmission and reception. With regard to location, the UE 402 may store its location with respect to different TRPs and may determine that one or more new beam processes may be sought from the new TRP. Upon deciding to add a new beam process, the UE 402 may indicate to the network the measurements taken or an explicit instruction to add one or more new beam processes (or to replace an existing beam process with the new beam process), which may initiate a new procedure for beam process acquisition.

[0119] If the UE 402 is able to add a new beam process without removing another beam process (such as if there are unused TRX chains remaining), the UE 402 may indicate that the new beam process may be added to the list of existing beam processes. Alternatively, the network may be informed of the UE's beam process capabilities and may begin adding a beam process without removing the previous beam process.

[0120] In another example embodiment, the UE 402 may indicate to the network that it cannot add a new beam process without either removing an existing beam process or at least modifying the parameters of the existing beam process. Additionally, the UE 402 may indicate a request to add a new beam process to an existing beam process. For example, the UE 402 may indicate that an existing beam process may be configured for a subset of time resources. The UE 402 may indicate a set of beam process(es) to use for such time resource restrictions.

[0121] The UE 402 may indicate to the possibly new TRP / cell / eNB which time resources to configure for the new beam process. The new beam process may be configured for an orthogonal set of time resources. This configuration change may allow for the coexistence of the new beam process with the previously configured beam process.

[0122] The UE 402 may maintain a set of beam processes. Elements of such a set may include beam processes that may be used simultaneously. Such a set may include fewer elements than the maximum number of TRX chains of either the UE 402 or the TRP / cell / eNB. Beam processes may be included in two or more sets. For example, the UE 402 may have a first beam process with no time restriction, a second beam process applicable to a first set of time resources, and a third beam process applicable to a second set of time resources orthogonal to the first set of time resources. In such a case, the UE 402 may maintain a first set of beam processes with the first beam process and the second beam process, and a second set of beam processes with the first beam process and the third beam process. The time restrictions for the previously configured beam processes and the new beam process may remain in place until further reconfigured by the network or until the UE 402 requests a parameter change on one or more beam processes.

[0123] In an example embodiment, upon triggering a mobility event, the UE 402 may assume that one beam process (or all beam processes) may use a pre-configured set of time resources. One beam process may be a master beam process, or the time resources may be determined based on the beam process ID. The UE may perform beam process acquisition on time resources that are orthogonal to the time resources used for the pre-existing beam process. Upon completing the mobility event, the UE 402 may assume that the new beam process is valid for all time resources, and the previously configured beam process that was restricted during the mobility event may be completely removed.

[0124] The UE 402 may use different beam process acquisition methods depending on the cause of the addition of a beam process. For example, if the cause is to increase the number of beam processes, such as to increase diversity or multiplexing, the UE 402 may attempt to acquire a new beam process based on rules tied to the existing beam processes. In this example, the UE 402 may test a limited set of beams (or beam groups or beam classes) to acquire a new beam process. The restriction may ensure the addition of a new beam process to the set of existing beam processes, and the new beam process is unlikely to be correlated with the existing beam processes.

[0125] In another example, when the UE 402 requests to add a new beam, for example by RLF, the UE 402 may initiate the process with a particular beam group and / or class. This methodology may ensure that a new beam process is found in a shorter period of time, regardless of whether the new beam process optimizes transmission / reception performance. For example, a UE 402 that has received an RLF using a beam of a particular beam class may attempt a new beam process acquisition using a beam of a higher or lower class.

[0126] The UE 402 may indicate a request to add a beam process to the network. Such an indication may include a cause for adding a beam process, an existing beam process to be replaced with the new beam process, or a beam process usage restriction. For example, the usage restriction may include a communication link direction (such as UL, DL, SL, or a combination). In another example, the usage restriction may include a transmission type (e.g., mMTC, URLLC, eMBB). In yet another example, the usage restriction may include a beam process parameter (e.g., SOM or numerology). In a further example, the usage restriction may include a purpose of the beam process (e.g., for data transmission or for mobility measurements). In another example, the usage restriction may list a subset of time resources expected to be used by the beam process.

[0127] The UE 402 may request to add or remove a beam process. Such a request may be made to the serving TRP / cell / eNB using dedicated resources. For example, the UE may send a request for removal of a beam process using the beam process itself. In another example, the UE may request to add a beam process to a TRP and indicate the TRP ID (or any parameter obtained on the MRS) to the source TRP.

[0128] In an example embodiment, the UE 402 may request to add a new beam process by using an RA-like procedure. The UE 402 may transmit a random access preamble using the beam to be used for the new beam process. This transmission may trigger an operation where only the TRP / cell / eNB beam is matched to the UE's beam for that beam process. In another example, the UE 402 may use a beam from the appropriate beam class of the specified RA. The procedure that follows may force optimization of both the UE's beam and the TRP / cell / eNB beam.

[0129] In another example embodiment, the UE 402 may have a dedicated beam and / or beam process for transmitting a request for beam addition (e.g., using an RA). Such dedicated beam and / or beam process may be configured by the network. In another example, the UE 402 may be configured with one or more beam processes for a specific use. Furthermore, one or more such beam processes may be tagged to be used for additional beam process requests.

[0130] In some embodiments, the UE 402 receives a beam process transmit multiplexing configuration for simultaneous beam processing.

[0131] In some embodiments, the UE 402 may be configured to transmit simultaneously to different TRPs when the associated beam processes may have comparable signal configurations, including subcarrier spacing, symbol length, resource block size, cyclic prefix length, etc. In such embodiments, uplink beam transmissions to different TRPs may use the same frequency resources and may be spatially multiplexed, with the uplink beams being directed to the TRPs in such a way that the separation between the beam patterns may be higher than a preconfigured threshold. A potential benefit of this approach may be the reuse of frequency resources and the resulting high uplink spectral efficiency.

[0132] In another embodiment, the uplink beam transmissions may be multiplexed using dedicated frequency resources for each beam process associated with a different TRP. The resulting uplink beam patterns may overlap, resulting in reduced beamforming complexity.

[0133] Alternatively, the UE 402 may use different orthogonal spreading codes for beam processes associated with different TRPs, and a code configuration may be received for each TRP.

[0134] Beam Selection Procedure The following sections describe methods and example embodiments for beam selection. It should be understood that although the example embodiments may be described in terms of a single beam or single beam process, in practice the procedures may be applied to multiple beam processes in parallel.

[0135] Beam Class Beams may generally be characterized as described, for example, in "Beam Peak Direction, 1990", IEEE Transactions on Beam-to-Beam Diffraction Analysis, Vol. 13, No. 1, pp. 1111-1115, 2003. As previously described, Figures 3A and 3B show the difference between the beam peak direction and the beam center direction. The beam peak direction refers to the maximum point for the beam, while the beam center direction refers to the central point of the beam's distribution.

[0136] 5 shows the differences between beam 506, beam group 508 and beam classes 502, 504. It also shows the differences between lower beam class 502 and higher beam class 504. A beam family in this example may consist of all beams of the same class.

[0137] Exemplary embodiments for maintaining links across beam classes Different beam classes may exhibit different coverage levels. In general, the more directional the beam, the better the coverage in a particular direction. This observation also means that there is often a trade-off between directivity and coverage. A wider beam may exhibit less coverage, which may be problematic for some types of traffic or control channels. When changing to a lower beam class, the UE may lose the radio link. Similarly, when the UE changes to a higher beam class, the UE may end up transmitting too much power for a given rate.

[0138] In an exemplary embodiment, the UE may be configured to scale its transmit power according to the beam class. For example, a lower beam class may use more power (for a given bit rate, transport format or MCS, etc.) compared to other higher beam classes. This configuration may be implemented, for example, using a predefined power scaling factor associated with the beam class. While this approach may lead to similar received power at the eNB and maintain the radio link, it also limits the data rate per beam class since power amplifiers are generally power limited.

[0139] In an example embodiment, the link may be maintained by using repetition on multiple beams. For example, the UE may be configured to repeat transmission of a given data block on multiple beams (e.g., belonging to the same beam group) over multiple time instances. The UE may be configured to use a predefined sequence of beams (e.g., within a beam group).

[0140] Repetition on multiple beams may be triggered, for example, when the UE changes to a lower beam class. In an example embodiment, this approach avoids segmentation due to coverage changes resulting from a change to a lower beam class and applies only to HARQ retransmissions.

[0141] In an example embodiment, the repetition on multiple beams may be triggered and controlled by the network. For example, the UE may receive an instruction on a control channel (e.g., DCI) to start repetition on multiple beams. Optionally, the instruction may include the beam class and / or beam group index to use to transmit the data. This instruction may accompany, for example, an instruction to change to a lower beam class.

[0142] In another exemplary embodiment, the UE may be configured to indicate (e.g., UCI) to the network when repetition on multiple beams is required (e.g., when the UE has data in its retransmission buffer to retransmit on multiple beams).

[0143] In yet another exemplary embodiment, the UE may transmit on a subset of beams at a time. More specifically, the UE may be configured to transmit repeated data on a subset of multiple beams in a single TTI. The UE may receive an ACK / NACK from the network and continue to transmit the repeated data on another subset of multiple beams. The UE repeats this process until it receives an ACK from the network or until it has transmitted on all associated beams.

[0144] Determining a set of available beams for selection A UE may be configured to select a beam for transmission on a subset of its beams (also referred to as the set of available beams), which may be configured by the network (e.g., semi-statically (e.g., over RRC) or dynamically (e.g., via DCI-type signaling)).

[0145] In an example embodiment, the UE may be configured to determine a set of available beams based on a beam class. For example, the UE may determine that the set of available beams corresponds to a beam group associated with a beam of a lower beam class, for example, linked to a beam process. In another option, the UE may determine a beam group based on a direction of arrival for a downlink reference signal associated with a beam process, for example. For example, the set of available beams may be a beam group of a lower beam class with a closest beam direction as a direction of arrival (DoA) of the downlink reference signal.

[0146] In an exemplary embodiment, the UE may be configured with a set of available beams constrained by angular restrictions. For example, these restrictions may be applicable to the direction of the beams. The UE may be configured to restrict the beam direction for the set of available beams to a particular angular distance from the DoA for the downlink reference signal associated with the beam process.

[0147] In another example, the UE may be configured to use any beam that is constrained to be within a certain beam space. The beam space may use angular limitations to set its boundaries. For example, the UE may determine that the set of available beams consists of any beam whose beam direction is within a set of values ​​(e.g., associated with the DoA of the downlink reference signal of the associated beam process). The UE may further apply one or more conditions with beams having any shape. In an exemplary embodiment, the UE may limit a certain amount of energy (e.g., 90%) of the beam to a certain angular limitation. For example, the angular limitation may be determined based on a network-configured angular difference value (ΔDoA) applied to the DoA of the downlink reference signal associated with the beam process.

[0148] The UE may be configured to determine which beam class to use for its uplink transmission. The network may configure the UE to use a particular beam class, such as via DCI or via semi-static signaling (such as RRC). In another exemplary embodiment, the UE may be configured to separately determine the most appropriate beam class based on factors stored by the UE.

[0149] The UE may determine the beam class to use for transmission based on the transmitted data. For example, the UE may be configured to use one or more beam classes for control information (such as RRC signaling or RACH access) and one or more beam classes for data transfer. In another example, the UE may be configured to use a beam class for each logical channel. The UE may use the beam class associated with the logical channel being transmitted. The UE may also store a rule for determining which beam class to use when multiple logical channels with different associated beam classes are multiplexed together. For example, the rule may use the lowest beam class of the beam classes associated with the logical channels multiplexed in that transport block.

[0150] In another example, the UE may be configured to use a particular beam class for different traffic types, such as mMTC, eMBB URLLC, or QoS. For example, the UE may be configured with the beam class directly in the QoS configuration, or the UE may be configured with an association table or filter that links the QoS to a particular beam class.

[0151] The UE may be configured to indicate to the network which beam class the UE uses in its UL transmissions. This information may be carried in the UCI or in a special MAC header or other type of signaling. The UE may indicate to the network when it changes beam class or only when the UE makes a decision on which beam class to use.

[0152] In another exemplary embodiment, the UE may be explicitly configured from the eNB to use a particular beam class. For example, an eNB UL grant may indicate a particular beam class to be used for uplink beamforming. In such a case, the beam class may be valid only for the duration of the grant. Alternatively, the UE may be semi-statically configured with the beam class to be used.

[0153] The UE and the network may maintain synchronization of the beam class state such that both the UE and the network remain aware at all times of which beam class is being used. Several approaches may achieve this synchronization. In one approach, the opposing entity acknowledges all beam class changes (e.g., at the MAC or RRC protocol level). In an example of this approach, the UE may indicate a beam class change via a special MAC control element and apply the change only when it receives a reliable acknowledgement from the network (e.g., from a DL MAC control element).

[0154] The UE may keep the beam class configuration until it changes the configuration or until the UE receives a message from the network to change it. The UE may be configured to change the beam class immediately and acknowledge the network message in its next transmission (e.g., in a MAC header or other control message), or the UE may apply the change only after acknowledging the network's message and receiving an acknowledgment from the network (e.g., a HARQ-ACK or other higher layer acknowledgment).

[0155] A UE may in fact be configured with multiple beam processes. To exploit the spatial diversity or spatial multiplexing capability of the channel, the network may control the direction of transmission for the associated downlink reference signal, and each beam process should lead to an independent propagation path. The UE avoids transmitting data on the same propagation path (beam) for different beam processes. When determining the set of available beams, the UE may be configured to exclude one or more beams related to other ongoing or active beam processes.

[0156] The UE may be configured to determine a set of beams related to a given beam process. The UE may create a list including beams that are the same as the selected beam in the (other) beam process, beams in a beam group associated with the beam process, beams within a range of beam indices for the selected beam of the (other) beam process, and beams within an angular distance of the selected beam of the (other) beam process. The beams in the beam group associated with the beam process include beam groups of a lower beam class associated with the selected beam of the beam process. The range of beam indices may be configured a priori by the network or via a specification. For example, the range of beams may include all beams within ±N beam indices from the selected beam.

[0157] The angular distance may be configured a priori by the network. Related beams include beams (for the same beam class) whose beam centers are within a certain maximum angular distance from the beam center of the selected beam for the (other) beam process. The maximum angular distance (e.g., in degrees or radians) may be configured by the network. For example, related beams include beams whose beam centers are within ±Δ of the beam center of the (other) beam process. max Alternatively, the set of related beams may be defined based on both the 3 dB (or other value) lobes of the beams and the beam center of the selected beam of the (other) beam process. max The incoming beams may be considered as relevant.

[0158] When configured with more than one beam process, the UE may be configured for each beam process to select a beam outside the set of related beams (considering all outside beam processes). The UE may be configured to select the best available (and unrelated) beam.

[0159] In an example embodiment, when the UE determines that the best beam to select falls within the set of associated beams and / or when the UE determines that the set of available beams is empty, the UE may be configured to stop transmitting on the associated beam process or the UE may inform the network (e.g., via control signaling) by transmitting on a different beam process that has an available beam. The UE may further indicate the beam process number or identity and the associated beam or beam process.

[0160] Selection Procedure The UE may determine the beam class, beam group, and beam to use for uplink transmission based on measurements of one or more downlink beams by using at least one of the following example embodiments: quality / spatial / energy metrics, periodicity, downlink control / data / reference signal transmission, single-stage measurement, or multi-stage measurement.

[0161] Beam quality metric measurements include SNR, E b The beam spatial information measurement may be based on the angle of arrival (AoA). The beam energy metric measurement may be based on the RSSI and wideband AGC settings.

[0162] Beam periodicity measurements may be periodic or aperiodic, where beam measurements may be scheduled by the network. During active downlink data transmission, measurement fields or gaps may be included in the measurement scheduling. Beam measurements may be configured in system broadcast information or higher layer dedicated signaling, including the measurement periodicity. The UE may be triggered for periodic measurements within a predefined period.

[0163] For downlink control / data / reference signal transmissions, beam measurements may be performed on downlink beams associated with downlink control information, downlink data transmissions, scheduled downlink reference signal transmissions (e.g., beam selection reference signals), or periodic downlink reference signal transmissions (e.g., beam selection reference signals).

[0164] Single-stage beam measurement may be measured using one or more beams from a beam group of one beam class pre-configured and selected by the UE for beam measurement, a beam class based on the target measurement beam class and uplink transmission service type for which the measurement should be used, or a sweep of beams applied in a continuous or arbitrary manner to cover the beam space where the target downlink beam may be received.

[0165] Multi-stage measurements may be measured using a continuation of the first measurement process, where one or more beams from a beam group of a first beam class are selected in a manner similar to a single-stage measurement to obtain a first measurement result, then using the next measurement, and based on the first measurement result, using one or more beams of a second beam class that may have one or more different characteristics compared to the first beam class (such as a reduced beam width or adjusted central direction), or a multi-stage sweep, where each stage may consist of a selected beam and may gradually reduce the beam spacing while the UE determines spatial information and quality metrics of the measured downlink beams.

[0166] Based on the measurement results, the UE may select at least one beam from a beam group of the beam class for uplink transmission using a linkage between the beam class used for the measurement and its associated beam class for uplink transmission, a calculation based on directional reciprocity, or a sweep of multiple selected uplink beams over the beam space based on the measurement.

[0167] Linkage of beam classes for measurement and for transmission may be included in the beam process. In some exemplary embodiments, the UE may select an uplink beam of the same beam class as that used for measurement. For example, the selected uplink beam may have a similar beam width, beam center direction, or beam spacing.

[0168] The directional reciprocity calculation may be, for example, between AoA and AoD. In an exemplary embodiment, the UE may select an uplink beam from a beam class using a beam center direction calculation based on the estimated AoA information and the beam width of the downlink measurement.

[0169] In a sweep of multiple selected uplink beams, the UE may select a group of beams of a beam class different from that used for measurement and sweep the beams over the measured downlink beam space.

[0170] The UE may set the beam-specific power for the selected beam based on the measurement and the expected power offset associated with the measured beam class signaled by the network, the uplink channel type and service for which the uplink transmission is intended, the priority and maximum limitations of the selected beam class, the maximum transmit power of each antenna element, the maximum EIRP of the UE uplink transmissions, and other configurations including EIRP adjustment instructions from the network that the UE may use to adjust the beam class or to maintain the beam class while adjusting power per element.

[0171] The UE may determine one or more of a beam class, beam group, and beam to use for uplink transmission based on the feedback received for the uplink beam sounding procedure. The sounding procedure may be scheduled and configured by the network. The configuration may include an antenna port configuration, a beam class indicator, a number of sounding beams, a time resource allocation, a frequency resource allocation, a reference signal configuration for the sounding beam, and an EIRP for the sounding beam. The antenna port configuration indicates which port should be used. The beam class indicator indicates which beam class may be used for sounding per antenna port. The number of sounding beams indicates how many sounding beams should be transmitted per antenna port. An exemplary embodiment for the time resource allocation may allocate a field of multiple symbols in the control field of one subframe or a gap of multiple symbols in the data section of one subframe. In another exemplary embodiment, a special subframe may be configured for the sounding procedure. An exemplary frequency resource allocation may be a group of subcarriers or resource blocks. An exemplary reference signal configuration of the sounding beam may be a basic Zadoff-Chu (ZC) sequence for each antenna port or for the UE. The EIRP of the sounding beam may include the beamforming gain and power for each antenna element.

[0172] The UE may randomly select a sounding beam according to the configured number of sounding beams from the beam group for the indicated beam class. For each sounding beam transmitted from the same antenna port, the UE may apply the same ZC basis sequence. The ZC basis sequence may be configured per antenna port. The sounding beams per antenna port may be transmitted one by one. Different antenna ports may have sounding beams that use different ZC basis sequences to maintain orthogonality.

[0173] In another exemplary embodiment, the ZC base sequence may be configured per UE, where each antenna port may be assigned by the UE based on downlink beam measurements by cyclic shifting. In such a case, the sounding beam reference signals may be orthogonal between the antenna ports of the UE.

[0174] Uplink beam sounding may be triggered by a pre-configured event, such as the UE entering fallback or the quality of the downlink data beam falling below a pre-configured threshold.

[0175] The UE may perform a multi-stage uplink beam sounding procedure for several scenarios, as described in the following exemplary embodiments. In one exemplary embodiment, the UE may be configured with a multi-stage sounding procedure request with a sequence of beam classes to use for each stage of the sounding procedure. The configuration may include time resources and reference signal configurations for each beam class. In another exemplary embodiment, the UE may autonomously determine the sequence of beam classes and use a predefined set of reference signal sequences reserved for autonomous uplink beam sounding, so that the network may detect the sounding beam. The UE may receive network feedback in control information received in the downlink beam. Such feedback control information may have a fixed timing relationship with the sounding beam transmission timing, and the UE may monitor the feedback based on the timing relationship. In another exemplary embodiment, the feedback may be included in the scheduled downlink data. The feedback content may be a bitmap to indicate which sounding beams may be received above a threshold and may be used for further sounding. The feedback may also include sounding beam metric information and reference signal indexes for those sounding beams. The UE may determine which beam class to use based on the received feedback. In an exemplary embodiment, the UE may use a beam class that follows the configured beam class sequence. The UE transmits the next set of sounding beams in the beam space of the previous sounding beam whose feedback exceeds the threshold. The network may configure new resource allocations for each stage or apply the same resources until the multi-stage sounding procedure is completed.

[0176] The UE may select an uplink beam based on the best sounding beam indicated in the feedback of the uplink beam sounding procedure. In another exemplary embodiment, the network may schedule one or more beams of a beam class according to the uplink beam sounding. The UE may receive the uplink beam and beam class configuration in the downlink control information.

[0177] The network may schedule beams of different beam classes for each antenna port depending on the uplink and service type of the uplink transmission. For example, the network may schedule a beam class for uplink control information transmission on one antenna port and another beam class for data transmission on another antenna port. The scheduling may be done using one or more fields in the DCI to indicate the beam and beam class.

[0178] The transmit beams may be multiplexed in the time and frequency domains. For example, in one subframe, the UE may use a beam class in the uplink control field and a different beam class in the uplink data field. In another exemplary embodiment, the UE may transmit simultaneous beams of different beam classes, where each beam may apply a different group of subcarriers or resource blocks.

[0179] The power of each beam class may be determined based on feedback from the uplink beam sounding procedure. Each beam class may have an independent maximum EIRP and maximum transmit power per antenna element. The power control per beam may be limited by the maximum EIRP of the beam class.

[0180] For a particular uplink channel transmission, the network may configure power control commands specific to the beam class. The UE may adjust the transmit power on a per-element basis. In another exemplary embodiment, the network may configure different beam classes for uplink transmission, and the UE may adjust the transmit power on a per-element basis according to the new beam class. For example, the reconfigured beam class may have a wider beam width, and the UE may increase the transmit power to maintain the total EIRP.

[0181] The network may schedule uplink beams and beam classes to maximize uplink transmission capacity and to avoid uplink transmission interference between co-scheduled UEs. In maximizing uplink transmission capacity, the network may use uplink beams based on the beam class with the best sounding results with a very narrow beam width. The procedure may increase the spectral efficiency for a single user. In avoiding uplink transmission interference, the network may, for example, evaluate the uplink beam sounding results from all UEs that may transmit to the same TRP and select a beam and beam class for each UE such that the transmission beam of one UE may have a null toward the main lobe direction of the transmission beam of the co-scheduled UE. This technique may enable the co-scheduled UEs to use the same time, frequency, and code resources and increase the average spectral efficiency per TRP.

[0182] The UE may trigger the uplink fallback procedure under multiple scenarios, such as when it receives a ramp-up TPC bit while receiving a downlink NACK of a data beam transmission and reaches the maximum EIRP for the beam class, when it receives a predefined number of NACK messages for a particular uplink beam used for data transmission, or when it enters a beam-misaligned state based on preconfigured criteria.

[0183] The UE fallback procedure may include the following actions: discontinuing use of the currently selected beam and beam class, selecting another beam class to continue uplink data transmission, setting the transmit power for each element according to the selected beam class, and initiating an uplink sounding procedure using predefined resources.

[0184] When selecting another beam class to continue the uplink data transmission, the new beam class may be the lowest beam class or a beam class with a predefined offset lower than the used beam class, and may have, for example, a wider beam width or a different beam center direction.

[0185] When setting the transmit power per element according to the selected beam class, the UE may increase the transmit power to compensate for reduced beamforming gain, e.g., when using a lower beam class. When the maximum power per element is reached, the UE may apply beam sweeping to provide cumulative gain.

[0186] Initiating the uplink beam sounding procedure using predefined resources may include reserving a reference signal sequence for the fallback trigger of the uplink beam sounding and allocating preconfigured time and frequency resources for the fallback trigger of the uplink beam sounding. For example, there may be symbol and subframe locations calculated based on UE and TRP identification information that may be used for sounding.

[0187] In another exemplary embodiment, the UE may send a fallback indicator to the network using an uplink beam of a different beam class (such as a beam used for uplink control information transmission from another antenna port). The uplink beam for the control transmission may experience uncorrected obstructions or channel events and may be used. The UE may receive an uplink sounding beam request and configuration to initiate uplink sounding. The resource configuration may not be reserved and may be dynamically configured. In another exemplary embodiment, the UE may receive an initial beam process request.

[0188] Maximum Power Reduction (MPR) by SAR The UE may receive human body monitoring information including detected distance and angular direction from the motion sensor. The UE may collate the human body detection data to determine which uplink beams may be within a predefined proximity of the detected human body. The UE may autonomously apply a maximum power reduction (MPR), e.g., of a predefined value, to each identified uplink beam. It should be noted that the maximum power may indicate the total Effective Isotropic Radiation Power (EIRP) emitted by the uplink beam pattern.

[0189] The UE may perform the maximum power reduction using one or more of a variety of different techniques. In one technique, the UE backs off the maximum transmit power for each element of all antenna elements associated with the identified uplink beam. In another technique, the number of antenna elements used for the identified uplink beam is reduced. Note that this may be implemented in a UE that has the capability to scale the number of antenna elements used for analog beamforming. The reduction of antenna elements may also cause a change in beam class. In another technique, the UE may switch to a different set of antennas that may be located on the opposite side to keep the radiation pattern at optimal power (this may be the case in the above 6 GHz bands if it has such capability).

[0190] The UE may autonomously determine how to reduce the total EIRP. In some embodiments, the network may pre-configure the UE with antenna element scaling capability with information on how MPR may be performed.

[0191] The UE may be configured with an indication of which method for reduction of the maximum EIRP should be applied, for example, whether the reduction should be applied by reducing the maximum power or by reducing the number of antenna elements. Such a configuration may be provided by higher layer signaling.

[0192] Beam process parameter update The UE may further identify which active beam processes may be associated with the uplink beam with the SAR-induced MPR and update the relevant parameters of the identified beam processes. The beam process specific parameters may include an updated maximum total EIRP, maximum configured power, obtained power headroom, and beam class. The beam class change may cause the UE to update an estimate of the interference received at the TRP in the uplink beam.

[0193] PHR triggered by MPR caused by SAR For each identified beam process, the UE shall ensure that it cmax For beam processes where SAR has changed, the UE may be triggered to send a report, such as a power headroom report (PHR) or an EIRP report, indicating new parameters applicable to the adjusted maximum power. In the report, the UE may specify the MPR cause, which is SAR related, and the identity of the affected beam process. The report may be transmitted as control information at the physical layer. In the latter case, the control information may be associated with the same or different beam processes. A potential benefit of using UCI transmission may be low latency and overhead, since SAR-induced MPR may become more frequent in HF NR beamformed operation. In another embodiment, the UE may transmit the report using MAC signaling or RRC signaling.

[0194] Maximum Gain Offset Reporting Triggered by MPR Caused by SAR The UE may be configured or autonomously apply MPR by reducing the number of antenna elements, thereby reducing the beamforming gain of the beam process. The UE may keep the power per element unchanged. The UE may be triggered to report a maximum gain offset report to indicate the offset between the applied beamforming gain of the beam process and the configured maximum gain. The eNB may trigger an uplink beam reselection for the beam process. In another solution, the eNB may reduce the transport format, such as the coding rate and modulation scheme, for the beam process with reduced beamforming gain to maintain the radio link. This may improve the robustness of the beam process during MPR.

[0195] Beam process reselection triggered by SAR The UE may reselect an active beam process that may have updated parameters and PHR as a result of the SAR-induced MPR. The uplink beam reselection may be performed according to a set of preconfigured rules. The UE may apply the rules according to the beam process uplink transmission type, the updated uplink transmission, the uplink channel type, and the uplink transmission mode and scheme. In some exemplary embodiments, the UE may change the beam process association by establishing a new beam process or switching to another active beam process with a new set of downlink and uplink beams.

[0196] Uplink Beam Reselection of Active Beam Process Affected by SAR The UE 602 may reselect an uplink beam of an active beam processed as a result of the MPR caused by SAR. As shown in the example embodiment 600 shown in FIG. 6, the UE 602 may reselect beam B1 (604) to replace beam B2 (606) for active beam processing due to the proximity of beam B2 (606) to the human body 608. The UE 602 may take into account the reduced maximum EIRP and MRP in the open-loop selection of the uplink beam. For example, the UE 602 may apply a negative EIRP reduction to an uplink beam that may correspond reciprocally to an active downlink beam associated with the beam processing. As a result, the UE 602 may not select an uplink beam that is reciprocal to an active downlink beam associated with the beam processing. The UE 602 may select another uplink beam based on the adjusted maximum EIRP of the available uplink beams, including those affected by SAR, rather than based on reciprocity. The UE 602 may also fall back to a default uplink beam that was preselected and maintained for the beam process.

[0197] The UE 602 may re-estimate the path loss of the reselected uplink beam. The "paired" downlink beam of each beam process may be a downlink data beam, or a reference beam, or other type of downlink beam. The pairing may not be a one-to-one mapping, and the path loss estimate may use the transmit power specified in the system broadcast information. The uplink power of the reselected uplink beam may be based on the re-estimated path loss. In another solution, the uplink power may be implicitly indicated using a periodic synchronization signal sequence.

[0198] The UE 602 may re-establish the transmission timing of the reselected uplink beam. Furthermore, the beam reselection may trigger uplink beam sweeping using the updated power, and the UE 602 may initiate the uplink beam pairing and beam reacquisition procedure. The beam reacquisition may not be based on the associated downlink beam using reciprocity. The UE 602 may update the re-paired downlink and uplink beams for the associated beam process. The UE 602 may send beam process update information to the eNB using the reselected uplink beam transmission.

[0199] Beam processing procedures triggered by rotation or obstruction detection data: Uplink beam reselection and re-pairing The UE 602 may periodically estimate the orientation change of the antenna array and update a local coordinate system that may be a reference for the beam direction. The UE 602 estimation may be based on rotation and obstruction detection data provided by motion sensors.

[0200] The UE 602 may autonomously fall back on one or more transmission properties, including transmission mode, transmission scheme, beamforming properties, etc. For example, the UE 602 may apply a preconfigured wide or omni-directional beamwidth. The increased beamwidth may allow a portion of the uplink transmission energy to reach the eNB around the detected obstruction through diffraction. Also, the wide beam pattern may reduce the effect of UE 602 rotation. The UE 602 may further use a preconfigured uplink control and data channel transport format, including a block size and a modulation and coding scheme (MCS). With the beamwidth widening, the total EIRP may be reduced, and the UE 602 may use a smaller block size and a conservative MCS to maintain the uplink quality.

[0201] In another embodiment, the UE 602 may initiate an uplink sounding transmission using uplink beam sweeping using a predefined uplink sounding configuration. The configuration may include a reference signal type and resource allocation. This may enable the UE 602 to identify an uplink beam that may not be affected by rotation or detected obstructions. The UE 602 may reselect an uplink beam based on the results of the initiated uplink sounding procedure. The UE 602 may transmit a measurement or uplink beam re-pairing request following the sounding procedure.

[0202] A UE 602 with multiple simultaneous active beam processes may initiate uplink beam reselection and re-pairing for each beam process upon rotation and obstruction detection. The UE 602 may apply orthogonal uplink resource configurations for uplink fallback and re-pairing transmissions in either the frequency domain or the time domain. In another solution, the UE 602 may have two spatially separated simultaneous beam processes, in which case the UE 602 may use the same frequency and time resources for beam process transmissions.

[0203] Downlink RLF Avoidance The obstruction may be the cause of UE downlink RLF, and the UE 602 may use the rotation vector and rate estimates to predict the condition. The UE 602 may apply rules or criteria to determine whether rotational movement or detected obstruction will cause RLF in a nearby time frame. The rules may include rates of SINR degradation, received energy decrease, and BLER increase. The UE 602 may transmit a preconfigured sequence to trigger a downlink beam reselection procedure using a control channel with a predefined transport format. In another solution, the UE 602 may apply an autonomous transmit OFF based on the sensing data, in which case the UE 602 may switch off all uplink transmit beams and suspend the active beam process. This prevents the UE 602 from wasting energy to operate in very unfavorable channel conditions, for example, with very fast rotational movement, very fast or large obstructions moving very quickly towards the UE 602. Beamformed transmission may not be viable in these conditions.

[0204] Downlink Beam Probing and Adjustment The UE 602 may request a beam-specific reference signal transmission for downlink beam adjustment. The UE 602 may monitor quality metrics of the downlink beam associated with the active beam process during active data reception. The quality metrics may include energy detection in the active beam pair on the assigned frequency resources, DMRS symbol energy above noise, and magnitude of detected rotation. The UE 602 may send a request for BSRS transmission when the monitored quality metric exceeds a predefined threshold. The beam-specific reference signal resource configuration may be preconfigured, and the UE 602 may use receive beam sweeping to initiate new beam pairing based on the detected BRS. The UE 602 may determine and update the receive beam associated with the active beam process.

[0205] The UE 602 may probe the receive beam periodically or triggered by a predefined event for each active beam process. The UE 602 performs receive beamforming probing every TTI or every number of TTIs averaged over a predefined time period during active downlink data transmission. The UE may use a CP or GP attached to each symbol, or a field specific to the subframe structure where there is no useful data transmission, especially for single receive beam UEs. The time period may also be scheduled as a special subframe or a block of one or more symbols. The UE 602 may also perform probing on a UW on the UE waveform without a CP or GP. For multiple receive beam UEs, the time period may overlap with data transmission, e.g., data and DMRS symbols.

[0206] Receive beamforming probing may include a complete receive beam sweep, cycling through receive beams, e.g., a predefined group of adjacent receive beams (GOB) or + / - x degrees (continuous BF), and / or the best receive beam previously used. The UE 602 may measure the detected energy for each adjusted receive beam and find the best receive beam according to predefined criteria.

[0207] The probing period may be short to reduce measurement overhead. Analog measurements may not require reference signal transmission for certain waveforms and may require short probing times. The UE 602 may update the active beam process with the receive beam selection as a result of the probing.

[0208] The UE 602 may also adjust the receive beams associated with the active beam process based on the results of the UE 602 rotation detection and receive beamforming measurements. The UE 602 may autonomously track the receive beams using a continuous analog beamforming capability. The UE 602 may perform receive beamforming adjustments during a predefined time period, similar to the receive beam probing configuration. The UE 602 may determine the adjustments based on the measured rotation vector, the detected active beam pair energy variation (wideband AGC value), the received channel SINR using the active beam pair, the channel quality measured in the receive beamforming measurements, etc. The UE 602 may apply the updated receive beams to continue active data reception without knowledge of the TRP. The UE 602 may update the active beam process with the receive beam adjustments and maintain the mapping of beam pairs between one or more receive beams and one transmit beam.

[0209] The UE may determine the “best beam” based on measuring the energy on a set of resources using a set of candidate beams. In some embodiments, the set of resources may be a specific time period or sequence of symbols within a downlink data transmission for the UE 602. The existence of the set of resources may be indicated in the downlink control information applicable to the transmission or may be configured by higher layers. In some solutions, the information mapped onto the set of resources may be coded and / or modulated using different parameters than those of the remaining resources of the transmission to increase the probability of successful decoding even when a suboptimal beam is used. The applicable parameters (e.g., code rate, modulation, or modulation and coding scheme index) may be indicated by the downlink control information or configured by higher layers, or may be implicitly determined from the parameters used in the remaining resources, such as a pre-determined or pre-configured offset to the MCS index applied for the remainder of the transmission.

[0210] Network Architecture Systems and methods relating to multicast group formation may be used in conjunction with wireless communication systems as described with respect to Figures 7A-7F. As a first matter, these wireless systems are described. Figure 7A is a diagram of an example communication system 700 in which one or more disclosed embodiments may be implemented. The communication system 700 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. The communication system 700 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth.

[0211] 7A, the communications system 700 may include WTRUs 102a, 102b, 102c, and / or 102d (which may be referred to generally or collectively as WTRUs 102), a RAN 103 / 104 / 105, a core network 106 / 107 / 109, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, consumer electronics, etc.

[0212] The communications system 700 may also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to enable access to one or more communications networks, such as the core network 106 / 107 / 109, the Internet 110, and / or the network 112. For example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each shown as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0213] The base station 114a may be part of the RAN 103 / 104 / 105, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals within a particular geographic area, sometimes referred to as a cell (not shown). The cell may be further divided into sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, one for each sector of the cell. In another embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and utilize multiple transceivers for each sector of the cell.

[0214] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 115 / 116 / 117, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 115 / 116 / 117 may be established using any suitable radio access technology (RAT).

[0215] More specifically, as mentioned above, the communication system 700 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 103 / 104 / 105 and the WTRUs 102a, 102b, 102c may implement a radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA®). WCDMA may include communication protocols, such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0216] In another embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 115 / 116 / 117 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A).

[0217] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX®)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM®), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0218] The base station 114b in FIG. 7A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to enable wireless connectivity in a localized area, such as an office, a home, a vehicle, a campus, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.11, to establish a wireless local area network (WLAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.15, to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 7A, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114b may not be required to access the Internet 110 via the core network 106 / 107 / 109.

[0219] The RAN 103 / 104 / 105 may be in communication with a core network 106 / 107 / 109, which may be any type of network configured to provide voice, data, application, and / or VoIP services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network 106 / 107 / 109 may provide call control, billing services, mobile location services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 7A, it will be appreciated that the RAN 103 / 104 / 105 and / or the core network 106 / 107 / 109 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 103 / 104 / 105 or a different RAT. For example, in addition to being connected to the RAN 103 / 104 / 105, which may utilize E-UTRA radio technology, the core network 106 / 107 / 109 may also be in communication with another RAN (not shown) that employs GSM radio technology.

[0220] The core network 106 / 107 / 109 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and IP in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another core network connected to one or more RANs, which may employ the same RAT as the RANs 103 / 104 / 105 or a different RAT.

[0221] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 700 may include multi-mode capabilities, i.e., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU 102c shown in FIG. 7A may be configured to communicate with a base station 114a that may employ a cellular-based wireless technology and may be configured to communicate with a base station 114b that may employ an IEEE 802 wireless technology.

[0222] 7B is a system diagram of the RAN 103 and the core network 106, according to an embodiment. As mentioned above, the RAN 103 may employ UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 115. The RAN 103 may also be in communication with the core network 106. As shown in FIG. 7B, the RAN 103 may include Node Bs 140a, 140b, 140c, which may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 115. The Node Bs 140a, 140b, 140c may each be associated with a particular cell (not shown) within the RAN 103. The RAN 103 may also include RNCs 142a, 142b. It will be appreciated that the RAN 103 may include any number of Node Bs and RNCs while remaining consistent with an embodiment.

[0223] As shown in FIG. 7B, the Node Bs 140a, 140b may be in communication with the RNC 142a. Additionally, the Node Bs 140c may be in communication with the RNC 142b. The Node Bs 140a, 140b, 140c may be in communication with the respective RNCs 142a, 142b via an Iub interface. The RNCs 142a, 142b may be in communication with each other via an Iur interface. Each of the RNCs 142a, 142b may be configured to control the respective Node Bs 140a, 140b, 140c to which it is connected. Additionally, each of the RNCs 142a, 142b may be configured to perform or support other functionalities, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, data encryption, and the like.

[0224] The core network 106 shown in Figure 7B may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, and / or a gateway GPRS support node (GGSN) 150. Although each of the above elements is shown as part of the core network 106, it will be appreciated that any one of these elements may be owned and / or operated by an entity other than the core network operator.

[0225] The RNC 142a in the RAN 103 may be connected to an MSC 146 in the core network 106 via an IuCS interface. The MSC 146 may be connected to the MGW 144. The MSC 146 and MGW 144 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to enable communications between the WTRUs 102a, 102b, 102c and legacy land-line communications devices.

[0226] The RNC 142a in the RAN 103 may also be connected to an SGSN 148 in the core network 106 via an IuPS interface. The SGSN 148 may be connected to a GGSN 150. The SGSN 148 and GGSN 150 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to enable communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0227] As mentioned above, the core network 106 may also be connected to networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0228] 7C is a system diagram of the RAN 104 and the core network 107, according to an embodiment. As mentioned above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the core network 107.

[0229] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be appreciated that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a may use multiple antennas, for example, to transmit wireless signals to and receive wireless signals from the WTRU 102a.

[0230] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users on the uplink and / or downlink, etc. As shown in FIG. 7C, the eNodeBs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0231] The core network 107 shown in Figure 7C may include a mobility management entity (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. Although each of the above elements is shown as part of the core network 107, it will be appreciated that any one of these elements may be owned and / or operated by an entity other than a core network operator.

[0232] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM or WCDMA.

[0233] The serving gateway 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The serving gateway 164 may also perform other functions, such as anchoring the user plane during inter-eNodeB handover, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0234] The serving gateway 164 may also be connected to a PDN gateway 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to enable communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0235] The core network 107 may enable communication with other networks. For example, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to enable communication between the WTRUs 102a, 102b, 102c and legacy land-line communication devices. For example, the core network 107 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the core network 107 and the PSTN 108. Additionally, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0236] 7D is a system diagram of the RAN 105 and the core network 109, according to an embodiment. The RAN 105 may be an Access Service Network (ASN) that employs IEEE 802.16 wireless technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 117. As described further below, communication links between different functional entities of the WTRUs 102a, 102b, 102c, the RAN 105, and the core network 109 may be defined as reference points.

[0237] As shown in FIG. 7D, the RAN 105 may include base stations 180a, 180b, 180c and an ASN gateway 182, although it will be appreciated that the RAN 105 may include any number of base stations and ASN gateways while remaining consistent with an embodiment. The base stations 180a, 180b, 180c may each be associated with a particular cell (not shown) in the RAN 105 and may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 117. In one embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. Thus, the base station 180a may use multiple antennas, for example, to transmit wireless signals to and receive wireless signals from the WTRU 102a. The base stations 180a, 180b, 180c may also provide mobility management functions such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement, etc. The ASN gateway 182 may act as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network 109, etc.

[0238] The air interface 117 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an R1 reference point that implements the IEEE 802.16 specification. Additionally, each of the WTRUs 102a, 102b, 102c may establish a logical interface (not shown) with the core network 109. The logical interface between the WTRUs 102a, 102b, 102c and the core network 109 may be defined as an R2 reference point (not shown) that may be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0239] The communication link between each of the base stations 180a, 180b, 180c may be defined as an R8 reference point that includes protocols for enabling WTRU handovers and the transfer of data between the base stations. The communication link between the base stations 180a, 180b, 180c and the ASN gateway 182 may be defined as an R6 reference point. The R6 reference point may include protocols for enabling mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

[0240] As shown in Figure 7D, the RAN 105 may be connected to a core network 109. The communication link between the RAN 105 and the core network 109 may be defined as an R3 reference point, including protocols for enabling data transfer and mobility management capabilities, for example. The core network 109 may include a Mobile IP Home Agent (MIP-HA) 184, an Authentication, Authorization, and Accounting (AAA) server 186, and a gateway 188. Although each of the above elements are shown as part of the core network 109, it will be appreciated that any one of these elements may be owned and / or operated by an entity other than a core network operator.

[0241] The MIP-HA 184 may be responsible for IP address management and may enable the WTRUs 102a, 102b, 102c to roam between different ASNs and / or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to enable communication between the WTRUs 102a, 102b, 102c and IP-enabled devices. The AAA server 186 may be responsible for user authentication and supporting user services. The gateway 188 may enable interworking with other networks. For example, the gateway 188 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to enable communication between the WTRUs 102a, 102b, 102c and legacy land-line communication devices. Additionally, the gateway 188 may provide the WTRUs 102a, 102b, 102c with access to the networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0242] Although not shown in Figure 7D, it will be appreciated that the RAN 105 may be connected to other ASNs and the core network 109 may be connected to other core networks. The communication link between the RAN 105 and the other ASNs may be defined as an R4 reference point (not shown), which may include protocols for coordinating mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and the other ASNs. The communication link between the core network 109 and the other core networks may be defined as an R5 reference point (not shown), which may include protocols for enabling interworking between a home core network and a visited core network.

[0243] FIG. 7E is a system diagram of an example WTRU 102. As shown in FIG. 7E, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a GPS chipset 136, and other peripherals 138. The transceiver 120 may be implemented as a component of a decoder logic 119. For example, the transceiver 120 and the decoder logic 119 may be implemented on a single LTE or LTE-A chip. The decoder logic may include a processor operable to execute instructions stored on a non-transitory computer-readable medium. Alternatively, or in addition, the decoder logic may be implemented using custom and / or programmable digital logic circuitry.

[0244] It will be appreciated that the WTRU 102 may include a sub-combination of the above elements while remaining consistent with the embodiments. Also, embodiments contemplate that the base stations 114a and 114b and / or nodes that they may represent, such as, but not limited to, transceiver stations (BTSs), Node Bs, site controllers, access points (APs), Home Node Bs, evolved Home Node Bs (eNodeBs), Home evolved Node Bs (HeNBs), Home evolved Node B gateways, and proxy nodes, among others, may include some or all of the elements shown in FIG. 7E and described herein.

[0245] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, other types of integrated circuits (ICs), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although FIG. 7E depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be incorporated together in an electronic package or chip.

[0246] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 115 / 116 / 117. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0247] 7E as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More particularly, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 115 / 116 / 117.

[0248] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, UTRA and IEEE 802.11.

[0249] The processor 118 of the WTRU 102 may be coupled to and receive user input data from the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, or the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0250] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0251] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 115 / 116 / 117 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information via any suitable location determination method while remaining consistent with an embodiment.

[0252] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos or videos), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, etc.

[0253] Figure 7F illustrates an example network entity 190 that may be used within the communication system 700 of Figure 7A. As shown in Figure 7F, the network entity 190 includes a communication interface 192, a processor 194, and non-transitory data storage 196, all of which are communicatively linked by a bus, network, or other communication path 198.

[0254] The communication interface 192 may include one or more wired communication interfaces and / or one or more wireless communication interfaces. For wired communication, the communication interface 192 may include one or more interfaces, such as, for example, an Ethernet interface. For wireless communication, the communication interface 192 may include components, such as one or more antennas, one or more transceivers / chipsets designed and configured for one or more types of wireless (e.g., LTE) communication, and / or any other components deemed suitable by those skilled in the art. Also, and further for wireless communication, the communication interface 192 may be equipped with a size and configuration suitable for serving the network side, as opposed to the client side, of wireless communication (e.g., LTE communication, Wi-Fi communication, etc.). Thus, the communication interface 192 may include appropriate equipment and circuitry (possibly including multiple transceivers) for serving multiple mobile stations, UEs, or other access terminals in a coverage area.

[0255] The processor 194 may include one or more processors of any type deemed suitable by one skilled in the art, with some examples including general purpose microprocessors and special purpose DSPs.

[0256] Data storage 196 may take the form of any non-transitory computer readable medium or combination of such media, some examples include flash memory, ROM, and RAM, to name just a few, such that any one or more types of non-transitory data storage deemed suitable by one of skill in the art may be used. As shown in FIG. 7F, data storage 196 includes program instructions 197 executable by processor 194 to perform various combinations of the various network entity functions described herein.

[0257] In some embodiments, the network entity functions described herein are performed by a network entity having a structure similar to that of network entity 190 of FIG. 7F. In some embodiments, one or more of such functions are performed by a set of multiple network entities in combination, where each network entity has a structure similar to that of network entity 190 of FIG. 7F. In various different embodiments, network entity 190 may be any of the following: RAN 103 (one or more entities therein), RAN 104 (one or more entities therein), RAN 105 (one or more entities therein), core network 106 (one or more entities therein), core network 107 (one or more entities therein), core network 109 (one or more entities therein), base station 114a, base station 114b, Node B 140a, Node B 140b, Node B 140c, Node B 140d, Node B 140e, Node B 140f ... The network entities may be, or at least include, one or more of: B 140b, Node B 140c, RNC 142a, RNC 142b, MGW 144, MSC 146, SGSN 148, GGSN 150, eNodeB 160a, eNodeB 160b, eNodeB 160c, MME 162, serving gateway 164, PDN gateway 166, base station 180a, base station 180b, base station 180c, ASN gateway 182, MIP-HA 184, AAA 186, and gateway 188. Certainly other network entities and / or combinations of network entities may be used in various embodiments to perform the network entity functions described herein, as the above list is provided by way of example and not by way of limitation.

[0258] Although the features and elements are described above in certain combinations, one skilled in the art will appreciate that each feature or element may be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, ROM, RAM, registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0259] Abbreviations used Δf Subcarrier Spacing 5gFlex 5G flexible radio access technology 5gNB 5GFlex Node B ACK Acknowledgement BB Baseband BLER Block Error Rate BTI Basic TI (at one or more integer multiples of the symbol duration) CB Contention-based (e.g., access, channel, resource) CoMP Multipoint Coordinated Transmission / Reception CP Cyclic Prefix CP-OFDM (Relies on Cyclic Prefix) Traditional OFDM CQI Channel Quality Indicator CSI Channel State Information CN Core network (e.g. LTE packet core) CRC Cyclic Redundancy Check CSG Limited Subscriber Group D2D Device-to-device transmission (e.g. LTE sidelink) DCI Downlink Control Information DL Downlink DM-RS Demodulation Reference Signal DRB Data Radio Bearer EIRP Equivalent Isotropically-Radiated Power EPC Evolved Packet Core FB Feedback FBMC Filtered Band Multi-Carrier FBMC / OQAM FBMC technique using offset quadrature amplitude modulation FDD Frequency Division Duplex FDM frequency division multiplexing ICC Industrial Control and Communications ICIC Inter-cell interference cancellation IP Internet Protocol LAA License Assisted Access LBT Listen Before Talk LCH Logical Channel LCP Logical Channel Prioritization LLC Low Latency Communication LTE Long-term evolution from e.g. 3GPP LTE R8 and above MAC Media Access Control NACK Negative ACK MBB Massive Broadband Communications MC Multi Carrier MCS Modulation and Coding Scheme MIMO Multiple Input Multiple Output MTC Machine Type Communication NAS non-access layer OFDM Orthogonal Frequency Division Multiplexing OOB Out of Band (Emission) P cmax Total available UE power during a given TI PHY Physical Layer PRACH Physical Random Access Channel PDU Protocol Data Unit PER Packet Error Rate PLMN Public Land Mobile Network PLR Packet Loss Rate PSS primary synchronization signal QoS Quality of Service (from a physical layer perspective) RAB Radio Access Bearer RACH Random Access Channel (or Procedure) RF Radio Front End RLF Radio Link Failure RNTI Radio Network Identifier RRC Radio Resource Control RRM Radio Resource Management RS reference signal RTT Round Trip Time SCMA Single Carrier Multiple Access SDU Service Data Unit SL Side Link SOM Spectral Operation Mode SS Sync Signal SSS secondary synchronization signal SRB Signaling Radio Bearer SWG Switching gap (in self-contained subframes) TB Transport Block TDD time division duplex TDM time division multiplexing TI Time interval (at one or more integer multiples of BTI) TTI (transmission time interval) (in one or more integer multiples of TI) TRP Sending / Receiving Points TRX Transceiver UE User Equipment UFMC Universal Filtered Multi-Carrier UF-OFDM Universal Filtered OFDM UL Uplink URC Ultra-Reliable Communications URLLC Ultra-Reliable and Low Latency Communications V2V Vehicle-to-Vehicle Communication V2X Vehicle Communications WLAN Wireless Local Area Networks and related technologies (IEEE802.xx domain) ZC Zadoff-Chu sequence

Claims

1. 1. A method performed by a wireless transmit / receive unit (WTRU) including a plurality of antenna elements, comprising: receiving, by the WTRU, configuration information indicating a plurality of antenna element configurations, at least one of the plurality of antenna element configurations having a respective identifier, at least one of the plurality of antenna element configurations being associated with a downlink reference signal, at least one of the plurality of antenna element configurations being provisioned with resources for the downlink reference signal, the provisioned resources including at least one identity parameter for generating a sequence for generating the downlink reference signal, as well as an indication of time and frequency resources; receiving, by the WTRU, downlink control information including an indication of the respective identifier of at least one of the plurality of antenna element configurations; determining, by the WTRU, an antenna element setting of the plurality of antenna element configurations based on an indication of the respective identifier of at least one of the plurality of antenna element configurations received in the downlink control information; transmitting using the determined antenna element configuration, the WTRU applying a set of precoding weights associated with the downlink reference signal; The method includes:

2. 2. The method of claim 1, further comprising: the WTRU receiving using the determined antenna element configuration, wherein using the determined antenna element configuration comprises applying a set of precoding weights associated with the downlink reference signal.

3. The method of claim 1 , further comprising: configuring additional antenna element settings in response to an indication received by the WTRU from a transmission / reception point.

4. The method of claim 1 , further comprising: configuring the WTRU with at least one of the plurality of antenna element settings by performing measurements on a downlink reference signal.

5. 5. The method of claim 4, wherein at least one respective antenna element setting of the plurality of antenna element settings is associated with an antenna element setting for transmission, the antenna element setting for transmission being determined by the WTRU by performing measurements on the downlink reference signal.

6. A wireless transmit / receive unit (WTRU) including a plurality of antenna elements, a transmitter, a receiver, a processor, and a memory, receiving, by the WTRU, configuration information indicating a plurality of antenna element configurations, at least one of the plurality of antenna element configurations having a respective identifier, at least one of the plurality of antenna element configurations being associated with a downlink reference signal, at least one of the plurality of antenna element configurations being provisioned with resources for the downlink reference signal, the provisioned resources including at least one identity parameter for generating a sequence for generating the downlink reference signal, as well as an indication of time and frequency resources; receiving downlink control information including an indication of the respective identifier of at least one of the plurality of antenna element configurations; determining an antenna element configuration of the plurality of antenna element configurations based on an indication of the respective identifier of at least one of the plurality of antenna element configurations received in the downlink control information; transmitting using the determined antenna element configuration, where using the determined antenna element configuration includes applying a set of precoding weights associated with the downlink reference signal; A WTRU configured to perform the following:

7. 7. The WTRU of claim 6, further configured to receive using the determined antenna element configuration, wherein using the determined antenna element configuration includes applying a set of precoding weights associated with the downlink reference signal.

8. The WTRU of claim 6 , further configured to configure additional antenna element settings in response to an indication received by the WTRU from a transmission / reception point.

9. The WTRU of claim 6 , further configured to configure the WTRU with at least one of the plurality of antenna element settings by performing measurements on a downlink reference signal.

10. 10. The WTRU of claim 9, wherein each antenna element setting of at least one of the plurality of antenna element settings is associated with an antenna element setting for transmission, the antenna element setting being determined by the WTRU by performing measurements on the downlink reference signal.

11. 1. A method for use with a wireless transmit / receive unit (WTRU) including multiple antenna elements, comprising: receiving, by the WTRU, configuration information indicating a plurality of antenna element configurations, at least one of the plurality of antenna element configurations having a respective identifier, at least one of the plurality of antenna element configurations being associated with a quasi-colocated downlink reference signal, at least one of the plurality of antenna element configurations being provisioned with resources for the quasi-colocated downlink reference signal, the provisioned resources including at least one identity parameter for generating a sequence for generating the downlink reference signal, as well as an indication of time and frequency resources; determining an antenna element setting from the plurality of antenna element settings based on an antenna element setting used to decode downlink control information from a downlink physical control channel transmission, the downlink control information indicating a downlink transmission; receiving a communication from a transmit / receive point (TRP) using the determined antenna element configuration, weighting the plurality of antenna elements with a set of precoding weights corresponding to the determined antenna element configuration, and using parameters associated with a quasi-co-located downlink reference signal corresponding to the determined antenna element configuration; The method includes:

12. 1. A wireless transmit / receive unit (WTRU) including a plurality of antenna elements, a processor, and a non-transitory computer-readable storage medium storing instructions, The instructions, when executed by the processor, cause the WTRU to: receiving configuration information indicating a plurality of antenna element configurations, at least one of the plurality of antenna element configurations having a respective identifier, at least one of the plurality of antenna element configurations being associated with a quasi-colocated downlink reference signal, at least one of the plurality of antenna element configurations being provisioned with resources for the quasi-colocated downlink reference signal, the provisioned resources including at least one identity parameter for generating a sequence for generating the downlink reference signal, as well as an indication of time and frequency resources; determining an antenna element setting from the plurality of antenna element settings based on an antenna element setting used to decode downlink control information from a downlink physical control channel transmission, the downlink control information indicating a downlink transmission; weighting the plurality of antenna elements with a set of precoding weights corresponding to the determined antenna element configuration, and receiving a communication from a transmission / reception point (TRP) using parameters associated with a quasi-co-located downlink reference signal corresponding to the determined antenna element configuration; The WTRU executes the above.

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