WO2018009462A1

WO2018009462A1 - Uplink beamforming and beam management

Info

Publication number: WO2018009462A1
Application number: PCT/US2017/040477
Authority: WO
Inventors: Yushu Zhang; Yuan Zhu; Huaning Niu; Wenting CHANG; Qinghua Li; Hua Li; Gang Xiong
Original assignee: Intel IP Corporation
Priority date: 2016-07-08
Filing date: 2017-06-30
Publication date: 2018-01-11

Abstract

Described is an apparatus of a User Equipment (UE). The apparatus may comprise a first circuitry and a second circuitry. The first circuitry may be operable to process Downlink (DL) signals received from the eNB. The second circuitry may be operable to determine a precoding matrix for Uplink (UL) transmission, based on processing the DL signals.

Description

UPLINK BEAMFORMING AND BEAM MANAGEMENT CLAIM OF PRIORITY

[0001] The present application claims priority to PCT Patent Application No.

PCT/CN2016/089438, filed July 8, 2016 and entitled "System and Method for Uplink Reciprocity Based Beamforming," to PCT Patent Application No. PCT/CN2016/092843 filed August 2, 2016 and entitled "Uplink (UL) Transmit (TX) Beam Tracking in Non-Reciprocity Channel," to United States Provisional Patent Application No. 62/374,191 filed August 12, 2016 and entitled "Uplink Beam Management Signal Structure and Control Signaling," and to PCT Patent Application No. PCT/CN2016/101212 filed September 30, 2016 and entitled "UL TX Beam Tracking Scheme in Non-Reciprocity Channel," which are herein

incorporated by reference in their entirety.

BACKGROUND

[0002] A variety of wireless cellular communication systems have been implemented, including a 3rd Generation Partnership Project (3 GPP) Universal Mobile

Telecommunications System, a 3GPP Long-Term Evolution (LTE) system, and a 3GPP LTE- Advanced (LTE-A) system. Next-generation wireless cellular communication systems based upon LTE and LTE-A systems are being developed, such as a fifth generation (5G) wireless system / 5G mobile networks system.

[0003] In high frequency band millimeter wave (mmWave) systems, such as 5G systems, the carrier frequency may be relatively high (e.g., compared to the carrier frequency of the LTE system). Accordingly, the signal power may decrease more rapidly as signals in the 5G system propagate, e.g., compared to that in lower band systems such as LTE. In an example, to overcome the increased pathloss and/or to provide wide coverage at high frequencies, large antenna arrays using beamforming techniques may be used at both the Evolved Node-B (eNB) side and the user equipment (UE) side for 5G systems. Thus, in 5G systems, massive multi-input multi-output (MIMO) may be applied, where beamforming may be employed the eNB side and the UE side.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The embodiments of the disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. However, while the drawings are to aid in explanation and

l understanding, they are only an aid, and should not be taken to limit the disclosure to the specific embodiments depicted therein.

[0005] Fig. 1 illustrates a system in which an uplink precoder is determined based on measuring downlink signals such as Beam Reference Signal (BRS), according to some embodiments.

[0006] Fig. 2 illustrates a system in which an uplink precoder is determined based on measuring downlink signals such as BRS, wherein a BRS index may be configured by a eNB based on a BRS-RP (BRS-Receiving Power) report from a UE, according to some embodiments.

[0007] Fig. 3 illustrates a system in which an uplink precoder is determined based on measuring downlink signals such as Channel State Information Reference Signal (CSI-RS), according to some embodiments.

[0008] Fig. 4 illustrates another system in which an uplink precoder is determined based on measuring downlink signals such as CSI-RS, according to some embodiments.

[0009] Fig. 5 illustrates possible switching in NW-UE (Network-UE) beam pair, according to some embodiments.

[0010] Fig. 6 illustrates larger subcarrier spacing based SRS symbols, according to some embodiments.

[0011] Fig. 7 illustrates a SRS symbol, according to some embodiments.

[0012] Fig. 8 illustrates three example formats of the SRS that may be used for three corresponding beam sweeping cases, according to some embodiments.

[0013] Fig. 9 illustrates an example UE UL (Uplink) beam pattern, according to some embodiments.

[0014] Fig. 10 illustrates a system, and depicts a procedure to select a UL beam under a non-reciprocity channel assumption, according to some embodiments.

[0015] Fig. 11 illustrates selection of Kl UL beams form among multiple UL beams, according to some embodiments.

[0016] Fig. 12 illustrates selection of beams in a set K2, according to some embodiments.

[0017] Fig. 13 illustrates an eNB and a UE, according to some embodiments.

[0018] Fig. 14 illustrates hardware processing circuitries for an eNB that selects an

UL beam for UL transmissions, according to some embodiments. [0019] Fig. 15 illustrates hardware processing circuitries for a UE to generate a precoding matrix for beamforming based on downlink signals, according to some embodiments.

[0020] Fig. 16 illustrates a method for a UE to generate a precoding matrix for beamforming based on downlink signals, according to some embodiments.

[0021] Fig. 17 illustrates a method for a eNB to select an UL beam for UL transmissions, according to some embodiments.

[0022] Fig. 18 illustrates an architecture of a system of a network, according to some embodiments.

[0023] Fig. 19 illustrates example components of a device, according to some embodiments.

[0024] Fig. 20 illustrates example interfaces of baseband circuitry, according to some embodiments.

DETAILED DESCRIPTION

[0025] High frequency band millimeter wave (mmWave) systems are about be implemented in near future. The 5G system is an example of such a high frequency band mmWave system. Any reference to a 5G system may also be a reference to a high frequency band mmWave system.

[0026] In a 5G system, to enable reciprocity based uplink beamforming (e.g., a reciprocal channel is assumed), a UE may measure downlink signals. In some embodiments, Beam Reference Signal (BRS) may be used by the UE for such purposes; while in some other embodiments, Channel State Information Reference Signal (CSI-RS) may be used by the UE, as discussed in further details herein. For example, based on measuring the downlink signals (e.g., the BRS and/or the CSI-RS), the UE may determine a precoder (e.g., a precoding matrix) for uplink transmission. For example, as channel reciprocity is assumed, the UE may determine the precoder for the uplink transmission, based on downlink signal measurements.

[0027] In some embodiments, BRS may be transmitted periodically and different network (NW) beams may be applied on the BRS signal. On the other hand, CSI-RS may be transmitted periodically or aperiodically (e.g., without any periodicity), and NW beams may be applied on the CSI-RS. In some embodiments, the NW beam in CSI-RS may be different from the NW beams in BRS, e.g., as a result of beam interpolation or combining. In some embodiments, a framework for uplink reciprocity based beamforming may be determined by a RS (Reference Signal), e.g., either BRS or CSI-RS, which may be used to determine the uplink precoder.

[0028] In the following description, numerous details are discussed to provide a more thorough explanation of embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring embodiments of the present disclosure.

[0029] Note that in the corresponding drawings of the embodiments, signals are represented with lines. Some lines may be thicker, to indicate a greater number of constituent signal paths, and/or have arrows at one or more ends, to indicate a direction of information flow. Such indications are not intended to be limiting. Rather, the lines are used in connection with one or more exemplary embodiments to facilitate easier understanding of a circuit or a logical unit. Any represented signal, as dictated by design needs or preferences, may actually comprise one or more signals that may travel in either direction and may be implemented with any suitable type of signal scheme.

[0030] Throughout the specification, and in the claims, the term "connected" means a direct electrical, mechanical, or magnetic connection between the things that are connected, without any intermediary devices. The term "coupled" means either a direct electrical, mechanical, or magnetic connection between the things that are connected or an indirect connection through one or more passive or active intermediary devices. The term "circuit" or "module" may refer to one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function. The term "signal" may refer to at least one current signal, voltage signal, magnetic signal, or data/clock signal. The meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0031] The terms "substantially," "close," "approximately," "near," and "about" generally refer to being within +/- 10% of a target value. Unless otherwise specified the use of the ordinal adjectives "first," "second," and "third," etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[0032] It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

[0033] The terms "left," "right," "front," "back," "top," "bottom," "over," "under," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions.

[0034] For the purposes of the present disclosure, the phrases "A and/or B" and "A or

B" mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0035] In addition, the various elements of combinatorial logic and sequential logic discussed in the present disclosure may pertain both to physical structures (such as AND gates, OR gates, or XOR gates), or to synthesized or otherwise optimized collections of devices implementing the logical structures that are Boolean equivalents of the logic under discussion.

[0036] In addition, for purposes of the present disclosure, the term "eNB" may refer to a legacy eNB, a next-generation or 5G eNB, an Access Point (AP), a Base Station or an eNB communicating on the unlicensed spectrum, and/or another base station for a wireless communication system. For purposes of the present disclosure, the term "UE" may refer to a legacy UE, a next-generation or 5G UE, an STA, and/or another mobile equipment for a wireless communication system.

[0037] Various embodiments of eNBs and/or UEs discussed below may process one or more transmissions of various types. Some processing of a transmission may comprise receiving, conducting, and/or otherwise handling a transmission that has been received. In some embodiments, an eNB or UE processing a transmission may determine or recognize the transmission's type and/or a condition associated with the transmission. For some embodiments, an eNB or UE processing a transmission may act in accordance with the transmission's type, and/or may act conditionally based upon the transmission's type. An eNB or UE processing a transmission may also recognize one or more values or fields of data carried by the transmission. Processing a transmission may comprise moving the transmission through one or more layers of a protocol stack (which may be implemented in, e.g., hardware and/or software-configured elements), such as by moving a transmission that has been received by an eNB or a UE through one or more layers of a protocol stack.

[0038] Various embodiments of eNBs and/or UEs discussed below may also generate one or more transmissions of various types. Some generating of a transmission may comprise receiving, conducting, and/or otherwise handling a transmission that is to be transmitted. In some embodiments, an eNB or UE generating a transmission may establish the transmission's type and/or a condition associated with the transmission. For some embodiments, an eNB or UE generating a transmission may act in accordance with the transmission's type, and/or may act conditionally based upon the transmission's type. An eNB or UE generating a transmission may also determine one or more values or fields of data carried by the transmission. Generating a transmission may comprise moving the transmission through one or more layers of a protocol stack (which may be implemented in, e.g., hardware and/or software-configured elements), such as by moving a transmission to be sent by an eNB or a UE through one or more layers of a protocol stack.

[0039] In some embodiments, an uplink receiving signal for one subcarrier may be defined by:

[0040] Y = W_j{_xHWi_xPX + N Equation 1.

[0041] In equation 1 , Y may denote a Np ^X x 1 receiving signal matrix. Also, W^_x may denote a Np ^X X analog receiving beamforming weight for beam j . In an example, H may indicate a frequency domain channel with the dimension x i j^ . Also, W _x may refer to the N g x N ^x analog transmitting beamforming weight for beam i. In an example, P may denote the N ^x X L digital precoder (e.g., a precoding matrix). Various embodiments of this disclosure discuss generation of the digital precoder P. N£^x may be the number of receiving antenna ports; and N ^x may be the number of transmitting antenna ports; i ^ may be the number of receiving antenna elements; and i j^ may be the number of transmitting antenna elements. N may be the noise plus interference; and L may be the number of layers. The channel is assumed to be reciprocal, and hence, the channel H may be the same for both uplink and downlink transmissions.

[0042] Fig. 1 illustrates a system 100 in which an uplink precoder is determined based on measuring downlink signals such as BRS, according to some embodiments. The system 100 comprises an eNB 102 communicating with a UE 104. The system 100 may be a LTE system, a 5G system, and/or the like. In some embodiments, the system 100 may be a 5G system. In some embodiments, a channel H between the eNB 102 and the UE 104 in the system 100 may be assumed to be reciprocal. For example, due to the reciprocity assumption of the channel, the UE 104 may use measurements of the downlink signals (e.g., BRS) to generate a precoder for uplink transmission. [0043] In some embodiments, the eNB 102 may transmit a BRS to the UE 104, illustrated as operation 108. In some embodiments, BRS may be an example of a

synchronization signal (SS) block. Merely as an example, SS may be utilized in LTE, while BRS may be used in 5G systems. For the purposes of this disclosure, BRS may be interchangeably used with SS signal or SS block.

[0044] In some embodiments, the BRS may be transmitted periodically (although only one instance of BRS transmission is illustrated in Fig. 1). In some embodiments, different NW beams may be applied to different BRS sequence. For example, a first NW beam may be applied to a first BRS transmission, a second NW beam may be applied to a second BRS transmission, and so on. In some embodiments, the UE 104 may select different UE beams to receive different BRS sequence, e.g., to get higher BRS Receiving Power (BRS- RP) for each NW beam. In some embodiments, a downlink channel may be obtained under different NW beams. In some embodiments, a precoder for different channel may be obtained by the Eigen value of the channel, shown in the equation 2 below:

[0045] USVj^H = Gj Equation 2.

[0046] In equation 2, Gj may denote an average effective channel covariance matrix estimated from beam j . In some embodiments, a first L columns of the matrix Vj may be the uplink digital precoder (e.g., the precoding matrix), e.g., if beam j is used to receive the uplink signal. In some embodiments, a rank L may be configured by higher layer signaling and/or may be transmitted via Downlink Control Information (DCI) signal. For example, the matrix Vj (e.g., the first L column) may include the digital precoder of equation 1.

[0047] In an example, a UE (e.g., the UE 104) may obtain different channel information from different beams, e.g., by detecting multiple BRS sequences. Accordingly, the UE 104 may receive information on which beam is used for uplink receiving, e.g., so that the UE 104 may select a correct precoder.

[0048] In some embodiments, the eNB 102 may inform the UE 104 on which beam is used to receive the uplink signal, e.g., using DCI and/or using higher layer signaling. For example, a BRS index may be added in the uplink grant to the UE 104, e.g., to inform the UE on which channel is used to prepare the digital precoder, as discussed in details herein later. The BRS index may be used to identify the BRS sequence. Also, a rank L for the precoder may be configured by the uplink grant. For example, in an uplink grant, a BRS index and a rank indicator (RI) may be added, as discussed herein in further details. [0049] Referring again to Fig. 1, at operation 108, periodic BRS signals may be transmitted from the eNB 102 to the UE 104. In some embodiments, based on the sequence of BRS signals, the UE 104 may estimate a best (e.g., an optimal or near optimal) UE analog beamforming weight for different beams. For example, the UE 104 may perform channel eigenvector calculation (illustrated as operation 110) based on receiving the sequence of BRSs. At operationl 12, the eNB 102 may transmit UL (uplink) grant (e.g., using DCI or other higher level signaling). The UL grant may be for Sounding Reference Signal (SRS).

[0050] In some embodiments, the eNB 102 may transmit the DCI (e.g., via UL grant of 112) for aperiodic SRS transmission, where a BRS index (e.g., which may be used to receive the SRS) may be included in the DCI of the UL grant of 112. Put differently, the UL grant of 112 may include the BRS index. In some embodiments, to support dual-beam operation, two different BRS indices may be transmitted in a single DCI, or in two corresponding DCIs. The BRS index may identify, to the UE 104, a channel that may be used to construct a digital precoder, and the BRS index may also be used to identify a BRS sequence. Based on the BRS index (e.g., which may be received via the UL grant), at operation 116, the UE 104 may transmit the SRS using best (e.g., optimal or near optimal) analog beam corresponding to the BRS index from the eNB 102.

[0051] In some embodiments, based on the SRS, the eNB 102 may select (illustrated as operation 120) the RI, the MCS, and/or a digital precoder (PMI) for a next xPUSCH (5G Physical Uplink Shared Channel) transmission. In some embodiments, the eNB 102 may transmit, at operation 124, a UL grant to the UE 104. The UL grant of operation 124 may include the BRS index and/or the RI.

[0052] In some embodiments, based on the BRS index and RI indicated by UL grant of 124, the UE 104 may determine or select an uplink precoder 127 (e.g., illustrated as operation 128). For example, the UE 104 may measure the downlink BRS signal that are periodically transmitted. Such measurement may be based on the BRS index received in the UL grant at 124. The UE 104 may use the measurement of the BRS signal to prepare the uplink precoder 127, e.g., based at least in part on equations 1 and 2, and the RI received via the UL grant. At operation 132, the UE 104 may transmit to the eNB 102 a xPUSCH. In some embodiments, the xPUSCH may include, or may be in accordance with, the uplink precoder 127 prepared in the operation 128.

[0053] Thus, in some embodiments and as discussed with respect to Fig. 1, downlink signal measurement (e.g., measuring BRS) may be used to derive the uplink precoder 127. The measurement of the downlink signal may be facilitated by the BRI index, which the UE 104 may receive via the UL grant.

[0054] Fig. 2 illustrates a system 200 in which an uplink precoder is determined based on measuring downlink signals such as BRS, wherein a BRS index may be configured by a eNB 202 based on a BRS-RP report from a UE 204, according to some embodiments. The system 200 comprises the eNB 202 communicating with the UE 204. The system 200 may be a LTE system, a 5G system, and/or the like. In some embodiments, the system 200 may be a 5G system.

[0055] Similar to Fig. 1, in some embodiments, in Fig. 2, the channel H between the eNB 202 and the UE 204 may be assumed to be reciprocal. For example, due to the reciprocity assumption of the channel, the UE 204 may use measurements of the downlink signals (e.g., BRS) to generate a precoder for uplink transmission. In the embodiments of Fig. 2, to reduce the overhead of control signaling, the BRS index may be implicitly configured based on the BRS-RP report.

[0056] For example, if a single beam (e.g., only a single beam) is enabled, the UE 204 may select a beam having a high power (e.g., having highest power among multiple beams, having power higher than a threshold, etc.), and may identify the beam having the high power in a BRS Receiving Power (BRS-RP) report. This beam may be the uplink receiving beam.

[0057] On the other hand, if dual-beam is enabled, the UE 204 may consider a beam having a high power in a corresponding antenna panel, and may identify this beam in the BRS-RP report. This may be considered as the uplink receiving beam. Accordingly, for dual-beam operation, the eNB 202 may select the antenna panel explicitly by the DCI (e.g., via UL grant), so that the UE 204 may receive the information of uplink receiving beam and prepare the precoder for xPUSCH.

[0058] Referring to Fig. 2, at operation 208, periodic BRS signals may be transmitted from the eNB 202 to the UE 204. In some embodiments, based on the sequence of BRS signals, the UE 204 may estimate an appropriate (e.g., a best, an optimal, or near optimal) UE analog beamforming weight for different beams. For example, the UE 204 may perform channel eigenvector calculation (illustrated as operation 210) based on receiving the sequence of BRSs.

[0059] In some embodiments, at operation 212, the eNB 202 may transmit a UL grant for the BRS-RP report. The UE 204 may generate the BRS-RP report, e.g., as discussed herein above. At operation 216, the UE 204 may transmit the BRS-RP report to the eNB 202. [0060] In some embodiments, the eNB 202 may receive the information of uplink receiving beam by decoding the BRS-RP report. For example, when receiving the SRS, the eNB 202 may directly use a specific uplink receiving beam based on the BRS-RP report, e.g., instead of sweeping multiple uplink receiving beams.

[0061] At operation 220, the eNB 202 may transmit a UL grant for SRS, and the UE

204 may transmit the SRS to the eNB 202 at operation 224. In some embodiments, based on the SRS, the eNB 202 may select (illustrated as operation 228) the RI, the MCS, and/or a digital PMI for a next xPUSCH transmission.

[0062] In some embodiments, the eNB 202 may transmit, at operation 232, a UL grant to the UE 204. In some embodiments, the UL grant of 232 may include a panel index and/or the RI. The panel index may identify one or more antenna panels (e.g., one panel). For example, in a 5G system, a UE may have multiple antenna panels, and the DCI or higher level signaling (e.g., via the UL grant of 232) may identify an antenna panel using the panel index. For example, the antenna panel having the high beam strength may be identified in the panel index.

[0063] In some embodiments, based on the panel index and RI indicated by UL grant, the UE 204 may determine an uplink precoder 235 (e.g., illustrated as operation 236). For example, the UE 204 may measure the downlink BRS signal (e.g., based on the panel index received in the UL grant at 232). For example, the panel index may identify an antenna panel of the UE. For example, for dual-beam transmissions, a panel index may identify two corresponding beams associated with the panel, and the UE may measure the two beams received by the antenna panel associated with the identified panel index (and may use the BRS of the strongest of the two beams received by the panel). Thus, based on the panel index, the UE may identify a beam, and use the BRS signal associated with the beam.

[0064] The UE 204 may use the measurement of the BRS signals to calculate the uplink precoder 235, e.g., based at least in part on equations 1 and 2, the BRS signals, and/or the RI received via the UL grant. At operation 240, the UE 204 may transmit to the eNB 202 a xPUSCH. In some embodiments, the xPUSCH may include, or bein accordance with, the uplink precoder 235 determined in operation 236.

[0065] Fig. 3 illustrates a system 300 in which an uplink precoder is determined based on measuring downlink signals such as CSI-RS, according to some embodiments. The system 300 comprises a eNB 302 communicating with a UE 304. The system 300 may be a LTE system, a 5G system, and/or the like. In some embodiments, the system 300 may be a 5G system. In some embodiments, a channel H between the UE 304 and the eNB 302 may be assumed to be reciprocal. For example, due to the reciprocity assumption of the channel, the UE 304 may use measurements of the downlink signals (e.g., CSI-RS) to generate a precoder for uplink transmission.

[0066] In some embodiments, the CSI-RS may be transmitted periodically or aperiodically (e.g., based on an appropriate triggering event). In some embodiments, there may be maximum a N number (merely as an example, N=8) of CSI-RS resources, and different NW beams may be applied to different CSI-RS resource. Accordingly, at a given time, the UE 304 may estimate the channel eigenvector from up to N number of beams.

[0067] In some embodiments, the eNB 302 may configure the beam index and RI explicitly by DCI, or by higher layer signaling. For example, the DCI or higher layer signaling (e.g., via an uplink grant) may include a CSI-RS Resource Index (CRI) and a rank indicator RI.

[0068] In some embodiments, the CRI may have log2N number of bits, and the RI may have log2(Lmax) number of bits, where Lmax may denote a maximum number of layers in uplink within one beam.

[0069] Referring again to Fig. 3, at operation 308, the eNB 302 may transmit the CSI-

RS, where such transmission may be aperiodic. In some embodiments, based on the CSI-RS signals, the UE 304 may estimate an appropriate (e.g., a best, an optimal or a near optimal) UE analog beamforming weight for different beams. For example, the UE 304 may perform channel eigenvector determination (illustrated as operation 310) based on receiving the sequence of CSI-RS.

[0070] At operation 312, the UE 304 may transmit a CSI report to the eNB 302. In some embodiments, the eNB 302 may receive information on uplink receiving beam, e.g., by decoding the CSI report. For example, the CSI report may indicate an appropriate (e.g., best identified) beam index. When receiving the SRS, the eNB 302 may directly use this uplink receiving beam (e.g., instead of sweeping multiple uplink receiving beams). In some embodiments, both the eNB 302 and the UE 304 may assume the uplink receiving beam for the xPUSCH is determined by the CSI-RS report.

[0071] At operation 316, the eNB 302 may transmit UL grant for SRS. At operation

320, the eNB 302 may receive the SRS. In some embodiments, the eNB 302 may perform selection of RI and MCS, e.g., at operation 324. In some embodiments, the eNB 302 may transmit the CRI and the RI to the UE 304, e.g., in operation 328. In some embodiments, dual-beam transmissions, the CRIs for the two uplink grants may be different. [0072] In some embodiments, the UE 304 may generate the uplink precoder 331 at operation 332. For example, the UE 304 may use the CRI, the RI, the eigenvectors (e.g., generated at 310), the CSI-RS measurements, etc. to generate the precoder 331. The UE 304 may transmit the precoder 331 via xPUSCH to the eNB 302, e.g., in operation 336.

[0073] Thus, in some embodiments and as discussed with respect to Figs. 1-2, in Fig.

3 downlink signal measurement (e.g., measuring CSI-RS) may be used to derive the uplink precoder 332. The measurement of the downlink signal may be facilitated by the CRI, which the UE 304 may receive via DCI or higher level signaling (e.g., via the UL grant).

[0074] Fig. 4 illustrates a system 400 in which an uplink precoder is determined based on measuring downlink signals such as CSI-RS, according to some embodiments. The system 400 and various operations associated with the system 400 may be at least in part similar to the corresponding ones in the system 300 of Fig. 3. For example, eNB 402, UE 404, operations 408, 410, 412, 416, 420, 424 and/or 436 may be similar to the corresponding operations of the system 300. However, unlike the operation 328 of the system 300, in the system 400 the operation 428 may involve transmitting a panel index within the UL grant.

[0075] In some embodiments, the DCI or higher level signaling (e.g., using the UL grant) may transmit, at operation 428 a panel index and/or the RI. The panel index may identify one or more antenna panels (e.g., one panel). For example, the a 5G system, a UE may have multiple antenna panels, and the DCI or higher level signaling (e.g., via the UL grant) may identify an antenna panel using the panel index. For example, the antenna panel having the high beam strength may be identified in the panel index.

[0076] In some embodiments, based on the panel index and RI indicated by UL grant, the UE 404 may determine the uplink precoder 431 (e.g., illustrated as operation 432). For example, the UE 404 may measure the downlink BRS signal (e.g., based on the panel index received in the UL grant at 428). For example, the panel index may identify an antenna panel of the UE 404. For example, for dual-beam transmissions, a panel index may identify two corresponding beams associated with the panel, and the UE 404 may measure the two beams received by the antenna panel associated with the identified panel index (and may use the BRS of the strongest of the two beams received by the panel). Thus, based on the panel index, the UE 404 may identify a beam, and use the CSI-RS signal associated with the beam.

[0077] Thus, in Figs. 1-4, a UE may use downlink channels, downlink beams, and/or downlink signals (e.g., BRS, CSI-RS, etc.) to determine a precoder, where the precoder may be used for uplink transmission. Such determination is based on an assumption on a reciprocity of the channel between the UE and the eNB. [0078] In some embodiments, in one or more of Figs. 1-4, the UE downlink Rx beam used to receive each NW beam may be equal to the UE uplink Tx beam, e.g., in order to enable reciprocity based uplink beamforming. In some embodiments, in one or more of Figs. 1-4, to enable the multiple receiving beams for different subbands, there may be more than one BRS index (e.g., in Figs. 1-2) and/or more than one CRI (e.g., in Figs. 3-4) in the uplink grant. The UE may decide which uplink receiving beam may be applied to which subband, e.g., without explicit signaling. The eNB may use one or more (e.g., all) of the beams indicated by multiple BRS index or CRIs to receive the xPUSCH.

[0079] In an example, beam management for uplilnk in multi-beam operation may be applicable to 5G systems. For example, the eNodeB and UE may maintain multiple beams. An appropriate (e.g., a best, an optimal, or a near optimal) Network (NW) and UE beam pair may help increase the link budget and SINR (signal-to-interference-plus-noise ratio). In an example, to achieve better performance, it may be desirable to keep the uplink in an appropriate (e.g., a good or at least a reasonable) NW-UE beam pair. For example, after initial access, the UE may achieve an appropriate NW-UE beam pair (e.g., a beam pair resulting in high SINR). However, as a result of UE mobility, rotation, blockage, etc., current NW-UE beam pair may not work well in future. Thus, an appropriate (e.g., an optimal or a near optimal) NW-UE beam pair may change with UE mobility, rotation of the UE handset, blockage, etc. Thus, it may be desirable to switch to a new NW-UE beam pair.

[0080] Fig. 5 illustrates possible switching in NW-UE beam pair, according to some embodiments. Fig. 5 illustrates three example scenarios. In each of these example scenarios, a eNB 502 is in communication with a UE 506. The eNB 502 may have example beam pairs 504a, ... , 504h; and the UE 506 may have example beam pairs 508a, ... , 508h. The number of eNB beams and/or UE beams in Fig. 5 are merely examples, and do not limit the scope of this disclosure.

[0081] In the example scenario 1, the UE beam for communicating with the eNB 502 is 508f. The initial eNB beam for communicating with the UE 506 may be 504b, and the eNB beam may be changed to 504e, e.g., to achieve an optimal, a near optimal, or good NE- UE beam pair. Thus, in the scenario 1, the eNB beam changes, while the UE beam remains unchanged.

[0082] In the example scenario 2, the eNB beam for communicating with the UE 506 is 504b. The initial UE beam for communicating with the eNB 502 may be 508f, and the UE beam may be changed to 508b, e.g., to achieve an optimal, a near optimal, or good NE-UE beam pair. Thus, in the scenario 2, the UE beam changes, while the eNB beam remains unchanged.

[0083] In the example scenario 3, the eNB beam for communicating with the UE 506 my change from 504b to 504e. The initial UE beam for communicating with the eNB 502 may be 508b, and the UE beam may be changed to 508f, e.g., to achieve an optimal, a near optimal, or good NE-UE beam pair. Thus, in the scenario 3, both the eNB beam and the UE beam change.

[0084] In some embodiments, to find new NW-UE beam pair which may be appropriate (e.g., optimal, near optimal, or good), beam sweeping may be performed at the eNB and/or the UE. Such beam sweeping may have enormous signaling overhead.

Accordingly, it may be desirable to have such beam sweeping with low or limited overhead, and to develop control signaling for uplink beam management. In some embodiments and as discussed herein in further details, uplink SRS structure may be used to enable beam sweeping with limited overhead.

[0085] In some embodiments, to enable the beam sweeping for either eNodeB side or

UE side, a first possible way may be to transmit multiple symbols with repeated signals structure. For example, if the beam is fixed in one side (e.g., one of the eNB side or the UE side), a best beam (e.g., a beam with highest power level, or with power level higher than a threshold) from the other side (e.g., another of the eNB side or the UE side) may be obtained by sweeping the beams for each repetition. However, in an example, if one repetition can be transmitted in one SRS symbol, the signaling overhead may be too large. For example, if there are 16 beams to be swept, 16 symbols may be used for beam sweeping, where such 16 symbols may be a too high overhead. In some embodiments, it may be desirable that multiple repetitions be mapped in a TDM (Time-Division Multiplexing) manner within one symbol, e.g., so that the signaling overhead may be reduced.

[0086] In some embodiments, to enable the beam sweeping for either eNodeB side or

UE side, another possible way may be to utilize a larger subcarrier spacing, by which the duration of one SRS symbol can be shorter than other symbols. As the SRS symbol length may decrease, the overall beam sweeping time and/or associated signaling overhead may also decrease. For example, in an embodiment, for the SRS with larger subcarrier spacing, the subcarrier spacing may be NxAf, where Αΐ may indicate the subcarrier spacing for other data and control signal, and N may be an integer. In such an example, in one OFDM symbol, there may be N number of SRS symbols. Thus, N number of beam sweeping may be done within one symbol. In some embodiments, the number N may be configured by higher level signaling or DCI (e.g., the eNB may transmit the value of N to the UE via higher level signaling or DCI, which the UE may store in a memory of the UE). If, for example, the eNB has P antenna panels (e.g., which can be considered to be Quasi-Co-Located (QCL)), a maximum of N*P network beams may be swept, e.g., if the beam sweeping is done at the eNB side. In some embodiments, the sequence may be repeatedly mapped to the resource grid. In some other embodiments, some sequence hopping may be applied to the sequence in different symbols.

[0087] Fig. 6 illustrates larger subcarrier spacing based SRS symbols, according to some embodiments. For example, Fig. 6 illustrates two OFDM symbols in the frequency- time map. A first OFDM symbol may comprise a plurality of data and/or control symbols, shaded using diagonal lines. A second OFDM symbol may comprise a plurality of SRS symbols, shaded using dots. Fig. 7 illustrates a SRS symbol, according to some

embodiments. The SRS symbol of Fig. 7 comprises four repetitions, each repetition comprising a corresponding cyclic prefix (CP) and data.

[0088] As illustrated in Fig. 6, in some embodiments, the subcarrier spacing for SRS may be N*Af, where Αΐ may indicate the subcarrier spacing for other data and control signal, and N may be an integer. In the example of Fig. 6, N is 4 (although such a value of N may be merely an example, and may not limit the scope of this disclosure). Thus, there may be 4 SRS symbols within one OFDM symbol. In some embodiments, the number N may be configured by higher level signaling or DCI (e.g., the eNB may transmit the value of N to the UE via higher level signaling or DCI, which the UE may store in a memory of the UE).

[0089] As illustrated in Fig. 7, the time domain signal for the SRS may comprise four repetitions, and each repetition comprising CP and SRS data (e.g., if the full band is allocated to one antenna port of one UE). Accordingly, four times beam sweeping may be achieved by a single SRS symbol. For example, each of the four example data patterns in the single SRS symbol of Fig. 7 may be respectively used for a corresponding beam of four beams. If the eNB has 4 QCL antenna panels, a maximum of 16 eNB beams may be swept in one SRS symbol. An appropriate (e.g., best, optimal or near optimal) beam may be the one with highest receiving power, or the one that has a power level higher than a threshold, etc.

[0090] In some embodiments, there may be multiple Antenna Ports (APs) for SRS transmission. Different antenna ports may be allocated for different UEs, or may be allocated to a same UE. The SRS for different APs may be mapped in a frequency divisional multiplexing (FDM) manner. For example, different subcarriers may be allocated to different APs. [0091] In some other embodiments, SRS for APs may be mapped in a TDM manner.

For example, different SRS symbols may be granted to different UEs. In some other embodiments, the SRS for the APs may be mapped in a Code-division multiplexing (CDM) manner. For example, different Orthogonal Cover Codes (OCC) may be applied to the APs. Also, different cyclic shifts may be applied to SRS in different APs. The AP index (or AP indices) for a UE may be indicated by, for example, DCI or higher layer signaling.

[0092] As illustrated in Fig. 5 and as also discussed with respect to Figs. 6-7, beam pairing between eNB beam and UE beam may change. Put differently, the NW-UE beam pair selected for communication may have to change with time (e.g., may change based on UE mobility, rotation of the UE, blockage, etc.). Figs. 6-7 illustrate using SRS structure for beam sweeping, to facilitate such beam pair change. In some embodiments, appropriate control signaling may be used to determine or identify the SRS symbols used for NW beam sweeping, and the SRS symbols used for UE beam sweeping.

[0093] In some embodiments, in a first case (e.g., corresponding to the first scenario of Fig. 5), NW beam sweeping (e.g., only NW beam sweeping, and not UE beam sweeping) may be performed. In some embodiments, in a second case (e.g., corresponding to the second scenario of Fig. 5), UE beam sweeping (e.g., only UE beam sweeping, and not NW beam sweeping) may be performed. In some embodiments, in a third case (e.g.,

corresponding to the third scenario of Fig. 5), both NW beam sweeping and UE beam swapping may be performed. In some embodiments, a feedback may be used by the eNB to the UE, e.g., to inform the UE the decision of beam switching for each case. In some embodiments, there may be a plurality of formats for the SRS signal, and one format can be used for one corresponding beam change case (e.g., of the above discussed three cases).

[0094] Fig. 8 illustrates three example formats of the SRS that may be used for three corresponding beam sweeping cases, according to some embodiments. The formats illustrated in Fig. 8 are mere examples, and the scope of this disclosure is not limited by the example formats illustrated in Fig. 8. In the example formats of Fig. 8, it is assumed that up to 4 beams in both eNodeB and UE side may be swept. Fig. 8 also assumes one antenna panel in the eNB side, and that the current NW-UE beam pair is NW beam 1 and UE beam 1.

[0095] Merely as an example, in a format 1 of the SRS, the UE 506 (e.g., of Fig. 5) may use (e.g., always use) a current UE beam (e.g., beam 1) to transmit multiple repetitions, which may be used for NW beam sweeping. Put differently, for SRS format 1, the UE may use the current UE beam 1 to transmit the SRS, and the eNodeB may sweep all four NW beams to select a new NW beam. Thus, the NW beam may be swept from beams 1, 2, 3, and 4. The format 1 may correspond to the above discussed first case (or the first scenario of Fig. 5), where NW beam sweeping (e.g., only NW beam sweeping, and not UE beam sweeping) may be performed. Because an OFDM symbol may include four SRS symbols (e.g., as discussed with respect to Fig. 6), the beam sweeping of format 1 may be accomplished in one OFDM symbol.

[0096] For SRS format 2 of Fig. 8, the eNB beam may be fixed, and the UE may sweep its beams to select a new UE beam. For example, the UE may try different UE beams in different repetitions, and the eNB may only use one NW beam (e.g., the current NW beam 1) to transmit the SRS. The format 2 may correspond to the above discussed second case (or the second scenario of Fig. 5), where UE beam sweeping (e.g., only UE beam sweeping, and not NW beam sweeping) may be performed. Because an OFDM symbol may include four SRS symbols (e.g., s discussed with respect to Fig. 6), the beam sweeping of format 2 may be accomplished in one OFDM symbol.

[0097] For the SRS format 3 of Fig. 8, the beam sweeping may be used in one side, while the beam in the other side is fixed, and this process may be repeated. For example, the UE may initially use beam 1 to transmit the SRS, and the eNB may sweep all the four NW beams. Subsequently, the UE may use beam 2 to transmit the SRS, and the eNB may sweep all the four NW beams, and so on. Thus, format 3 may be a combination of formats 1 and 2. In some embodiments, in format 3, all possible combinations of NW-UE beam pair may be swept. The UE may try one UE beam in K SRS symbols (K<M), e.g., K=4 SRS symbols, where M (e.g., M=14) may be the number of candidate UL beams. Merely as an example, because an OFDM symbol may include four SRS symbols (e.g., s discussed with respect to Fig. 6), the beam sweeping of format 3 may be accomplished in four OFDM symbols.

[0098] In some embodiments, the eNB may indicate to the UE the SRS format via, for example, DCI, where the DCI may be used to grant the SRS transmission. In some embodiments, the eNB may indicate to the UE the SRS format via, for example, DCI, where the DCI may be used for other channel transmission, e.g. transmission of xPUSCH and xPDSCH. In some embodiments, the UE may transmit the SRS "x" number of subframes after the subframe when the SRS grant is transmitted to the UE, where "x" may be predefined by the specification, configured by higher layer signaling, and/or configured by the DCI.

[0099] In some embodiments, different UEs may be configured with different formats within a subframe. Merely as an example, a first UE (e.g., UE1) may transmit format 1 SRS on a first four symbols, and a UE2 transmits format 3 SRS on remaining SRS symbols. [00100] In some embodiments, different OFDM symbols allocated for the SRS transmission from a UE may be configured by DCI. In some embodiments, format of individual SRS symbols may be configured by higher layer signaling.

[00101] In some embodiments, for a SRS format (e.g., formats 1, 2, and/or 3 of Fig. 8), short OFDM symbol duration may be configured for gradual beam change. For example, one OFDM symbol may be configured for gradual beam change.

[00102] In some embodiments, for a SRS format (e.g., formats 1, 2, and/or 3 of Fig. 8), long OFDM symbol duration (e.g., comprising 2 OFDM symbols) may be configured for abrupt beam change.

[00103] In some embodiments, a flag may be added in the DCI or higher level signaling, e.g., to distinguish whether short OFDM symbols or long OFDM symbols may be used for the current SRS format. In some embodiments, variables K and/or M (e.g., discussed herein above) may be configured by the DCI and/or higher layer signaling. Thus, the DCI and/or higher layer signaling may configure various variables associated with the SRS.

[00104] In some embodiments, the eNB may indicate to the UE (e.g., via DCI or higher level signaling) what format (e.g., one of formats 1, 2, and 3 of Fig. 8) to be used for beam sweeping.

[00105] In some embodiments, after receiving the SRS, the eNB may provide feedback on the beam switching to the UE. For example, the feedback may include one or more than one NW-UE beam pair indicated by the SRS symbol index. In some embodiments, the eNB may recommend one BRS index for one NW-UE beam pair, by which the UE may estimate a pathloss for current beam pair to perform the uplink power control. The feedback may be transmitted via DCI, via higher level signaling, and/or via MAC (Media Access Control) element. For example, in the uplink grant, a beam pair index may be added to indicate the UE beam index as well as the pathloss used to determine the transmitting power.

[00106] In a high frequency band millimeter wave (mmWave) systems, such as 5G systems, the signal power may decrease more rapidly, e.g., compared to systems with lower band signals. In an example, to overcome the increased pathloss and provide wide coverage at high frequencies, large antenna arrays using beamforming techniques may be used at both the eNB and UE side. In some embodiments, the UE may have multiple antenna panels and corresponding multiple beam candidates. Selecting an appropriate transmission beam (TX beam) may impact the uplink transmission performance. Also, as the UE may be mobile and the channel condition may change frequently, the eNB may track the UL TX beam in time, and may inform UE about a UL beam index to be used by the UE. If channel reciprocity is assumed, the downlink channel information may be used to select the UL TX beam.

However, in many cases, the channel may not be reciprocal (e.g., the channel reciprocity cannot be assumed). Various embodiments discussed herein below may consider UL beam tracking schemes, with non-reciprocity channel assumption.

[00107] There may be several challenges for UL beam tracking under non-reciprocity channel assumption. For example, there is no such UL beam tracking reference in 5G standard. Also, both UL TX beam number and eNB RX beam number may be relatively large in 5G systems. For example, suppose there are 48 eNB Rx beam and 14 UL TX beam candidate. The UE may have to transmit 48*14, i.e., 672 times, for the eNB to figure out the best UL TX beam index, which may have higher latency, and may be time consuming.

[00108] Fig. 9 illustrates an example UE UL beam partem 900, according to some embodiments. In the example beam pattern 900, 14 example TX beams are illustrated, although a UE may have any other appropriate number of UL beams. The beams 1, ... , 14 may be illustrated with respect to an Azimuth angle of Departure (AoD) and Zenith angle of Departure (ZoD). Each of the beams 1, ... , 14 may be transmitted by a corresponding antenna panel. For example, the UE (e.g., the UE 506 of Fig. 5) may maintain a set of TX beams. When accessing the network, the UE may select one or more appropriate or best beams to attach.

[00109] Assume there are M candidate Tx beams for the UE. In some embodiments, the UE may perform a beam sweeping based on (M/N) SRS symbols, where N may be a number of beam sweeping that may be done via a single SRS symbol. The eNB may select an appropriate Tx beam from among the M candidate beams, and the eNB may transmit a beam index to inform the UE on the selected Tx beam. The UE may use the selected TX beam for communication. However, in an example, such a method to select a UL TX beam may result in higher SRS overhead (e.g., especially if the eNB has to do some Rx beam refinement as well as the Tx beam refinement).

[00110] In Fig. 9, a beam may have one or more neighboring beams. For example, beams 1, 3, and 9 may be the neighboring beams of beam 2. If a number of neighboring beams are to be expanded, then beams 1, 8, 9, 10, and 3 may be the neighboring beams of beam 2. For example, each beam in Fig. 9 may be transmitted with a corresponding horizontal angle and a corresponding azimuth angle. Two beams may be said to be neighboring beams if, for example, the horizontal angles and/or the azimuth angles of the two beams may be consecutive, or overlapping, or reasonably close to each other. For example, 14 antenna panels of the UE may respectively transmit the 14 beams, and the neighboring beams may have antenna panels that have nearly same or very close azimuth angle of Departure (AoD) and/or zenith angle of Departure (ZoD), as illustrated in Fig. 9.

[00111] Fig. 10 illustrates a system 1000, and depicts a procedure to select a UL beam under a non-reciprocity channel assumption, according to some embodiments. In the system 1000, the UL beam sweeping may rely on some prior information, so that the overhead of the SRS signaling may be reduced. In some embodiments, the system 1000 comprises a eNB 1002 and a UE 1004. The channel between the eNB 1002 and UE 1004 may be assumed to be non-reciprocal, although the channel may be reciprocal in some examples.

[00112] In the example system of Fig. 10, the candidate UL TX beams are assumed to be M beams, e.g., the 14 beams illustrated in Fig. 9. As discussed previously, the 14 candidate beams are merely examples, and do not limit the scope of this disclosure.

[00113] Referring again to Fig. 10, during a procedure 1, the eNB 1002 may transmit a

DCI 1008 (or an appropriate higher level signaling) to the UE 1004. In some embodiments, the DCI 1008 may comprise a prior beam indicator 1012, an identification of Kl UL beams, and/or an identification of Nl symbols. The DCI 1008 may trigger subsequent SRS transmissions.

[00114] In some embodiments, the prior beam indicator 1012 may be a flag (e.g., a single bit flag). For example, assume, merely as an example, that the current UL beam used by the UE 1004 is beam 5 of Fig. 9. A first value of the prior beam indicator 1012 (e.g., a value of 0) may indicate to the UE 1004 that the current UL beam (e.g., beam 5) may not be taken into account while selecting candidate beams for beam sweeping. The candidate beams for beam sweeping may be selected independent of the current beam 5.

[00115] On the other hand, a second value of the prior beam indicator 1012 (e.g., a value of 1) may indicate to the UE 1004 that the current UL beam (e.g., beam 5) may be taken into account while selecting candidate beams for beam sweeping. The candidate beams for beam sweeping may be selected, based on the current beam 5. For example, beams that are neighboring to the current beam 5 (e.g., beams 4, 12, and 6) may be selected for beam sweeping.

[00116] In the example DCI 1008 of the procedure 1, the prior beam indicator 1012 may have a value of 0 (e.g., the current UL beam may not be taken into account while selecting candidate beams for beam sweeping). However, as discussed herein later, in the procedure 3 (e.g., in DCI 1020), the prior beam indicator 1012 may have a value of 1 (e.g., a UL beam may be taken into account while selecting candidate beams for beam sweeping). [00117] In some embodiments, the DCI 1008 may also include identification of Kl number of beams. Merely as an example, Kl = {2, 6, and 11 } . For example, Fig. 11 illustrates selection of Kl UL beams form among the possible UL beams, according to some embodiments, where the Kl beams are shaded using dots.

[00118] Merely as an example, the identification of Kl UL beams may comprise a number. For example, the identification of Kl UL beams may comprise three, e.g., to indicate to the UE 1004 that the UE 1004 may transmit 3 candidate beams to the eNB in subsequent procedure 2 (e.g., the UE 1004 may select 3 beams from the 14 candidate beams of Fig. 9). In another example, the identification of Kl UL beams may comprise example beam indices (e.g., beam indices 2, 6, 11).

[00119] In some embodiments, the DCI 1008 may also include an identification of Nl symbols, where Nl= p*Kl . The variable p may be an integer with a value of one of 1, 2, or P. The variable p may imply that the one Tx beam may be sent out in p SRS symbols. If p=l, one Tx beam may be transmitted in one SRS symbol. If p>l, each Tx beam in the set Kl may be transmitted in consecutive p SRS symbols. In this way, the eNB 1002 may further make use of the same TX beams in multiple symbols, e.g., to select an appropriate Rx beam from a candidate of multiple RX beams. Thus, for example, to enable the Tx beam sweeping and Rx beam sweeping, the eNB 1002 may inform the UE how many SRS symbols may be utilized for one Tx beam, which may be pre-defined or configured via higher layer signaling or DCI (e.g., via the DCI 1008). The number of SRS symbols in one subframe may be pre-defined or configured by higher layer signaling or DCI. In some embodiments, an example of an indicator for a number of SRS symbols for one TX is defined below in Table 1. The SRS symbol indicator may be transmitted from the eNB 1002 to the UE 1004 via DCI (e.g., DCI 1008), or higher level signaling.

[00120] Table 1 : an example for an indicator indicating a number of SRS symbols for one TX beam

3 4 SRS symbols, for Tx beam scanning and possible

Rx beam refinement, 1 Tx beam is applied to 1

SRS symbols, feedback may be enabled.

4 4 SRS symbols, for Tx beam scanning and Rx

beam refinement, 1 Tx beam is applied to 2 SRS symbols, feedback may be enabled.

5 12 SRS symbols, for Tx beam scanning and

possible Rx beam refinement, 1 Tx beam is applied to 1 SRS symbols, feedback may be enabled.

6 12 SRS symbols, for Tx beam scanning and

possible Rx beam refinement, 1 Tx beam is applied to 2 SRS symbols, feedback may be enabled.

7 12 SRS symbols, for Tx beam scanning and

possible Rx beam refinement, 1 Tx beam is applied to 4 SRS symbols, feedback may be enabled.

[00121] Thus, for example, a value of "0" of the SRS symbol indicator may indicate 1

SRS symbol for uplink link adaptation only or Rx beam refinement, and without feedback corresponding feedback. In another example, a value of "1" of the SRS symbol indicator may indicate 2 SRS symbols, for Rx beam refinement, current Tx beam to be applied to 2 SRS symbols, and without any feedback.

[00122] Referring again to Fig. 10, in procedure 2, the UE 1004 may transmit the SRS with the Kl beams in Nl symbols. As the prior beam indicator 1012 in the DCI 1008 is 0, the UE 1004 may select the Kl beams by sub-sampling the full angle space (e.g., as illustrated in Fig. 9). For example, the total M candidate Tx beams (e.g., where M =14 in the example of Fig. 9) may be divided into several groups, and the UE 1004 may select a first number of beams evenly distributed from each group of the M candidate beams, where the first number may correspond to Kl . For example, Kl beams may be a subset of the M candidate beams, and the Kl beams may be distributed as evenly possible among the M candidate beams. For example, in the example of Fig. 9, Kl may include beams 2, 6, and 11 (although in another example, Kl may include 4, 9, and 13). The Kl beams may cover the full Azimuth and Zenith angle. For example, each beam in the M candidate beams may either be in the Kl beam subset, or may be a neighbor of a beam in the Kl beam subset.

[00123] If K1=N1 (e.g., the above discussed variable p is 1), each SRS symbol may be weighted by a corresponding beam. If Nl=p*Kl and p>l, then p SRS symbols may be weighted by the same beam.

[00124] In procedure 2.5, the eNB 1002 may select an appropriate beam 1016 from the

Kl beams. For example, the eNB 1002 may select a best, an optimal, a near optimal beam, a beam with highest power level, a beam with power level power level higher than a threshold value, etc. 1016 from the Kl beams. Merely as an example, the appropriate beam 1016 is beam 2.

[00125] In procedure 3, the eNB 1002 may transmit a DCI 1020 to the UE 1004. In some embodiments, the DCI 1020 may include one or more of the prior beam indicator, a selected beam index indicator (discussed below in table 2), an identification of the selected beam (e.g., beam 2), and/or the like. In some embodiments, the DCI 1020 may also indicate a first number and a second number, where the UE is to transmit the first number of beams to in the second number of SRS symbols. In some embodiments, the prior beam indicator in the DCI 1020 may be 1, e.g., to indicate that the UE 1004 may select the candidate beams based on the selected beam index indicator.

[00126] In some embodiments, the eNB 1002 may send the Tx beam index

information to the UE 1004, e.g., for a case when prior beam indicator is not included in the DCI 1008. For example, the eNodeB may transmit, to the UE, one or more selected beam index from sweeping beams the UL beams. In some embodiments, for the case when prior beam information is included (e.g., in the DCI 1020), the eNB 1002 may transmit the selected one or more beam index from the sweeping beams, as well as the current Tx beam index. Table 2 illustrates an example of the selected beam index indicator in the DCI 1020.

[00127] Table 2: an example for selected beam index indicator

[00128] Thus, in the DCI 1020, the prior beam indicator may be 1. Also, the eNB

1002 may identify the selected beam 2 to the UE 1004. The selected beam index indicator may be 0, if, for example, the beam 2 is the current TX beam. If the selected beam 2 was transmitted in first SRS symbol(s) in the procedure 2, then the selected beam index indicator may be 1 ; if the selected beam 2 was transmitted in second SRS symbol(s) in the procedure 2, then the selected beam index indicator may be 2; and if the selected beam 2 was transmitted in third SRS symbols in the procedure 2, then the selected beam index indicator may be 3.

[00129] Thus, in some embodiments, a combination of the prior beam indicator and the selected beam index indicator may provide an indication to the UE 1004 that the selected beam is beam 2. As discussed, the DCI 1020 may include the prior beam indicator and the selected beam index indicator. In some other embodiments, the DCI 1020 may include an explicit identification of the beam 2, e.g., may include a beam index of beam 2.

[00130] In some embodiments, a set of candidate beams K2 may be formed based on the selected beam 2, where the set K2 may include beams that are neighboring to the selected beam 2. Fig. 12 illustrates selection of beams in the set K2, according to some embodiments. For example, beams 1 , 3, and 9 are neighboring the selected beam 2. Accordingly, the set K2 may be { 1, 3, 9} . In some embodiments, the set K2 may also include the original selected beam 2, and in such embodiments, K2 = { 1 , 2, 3, 9} . In another example, if a higher set of beams are desired in the set K2, then beams 8 and 10 may also be included in the set K2.

[00131] Thus, in some embodiments, upon receiving the DCI 1020, the UE 1004 may identify that the eNB 1002 has selected beam 2 from the set Kl, e.g., based on the prior beam indicator and the selected beam index indicator included in the DCI 1020. In some embodiments, the UE 1004 may generate the set of beam K2, such that the beams in the set K2 may be neighboring to the selected beam 2. As discussed herein above and as illustrated in Fig. 12, the set K2 may be { 1 , 3, 9} . In another example, the set K2 may be { 1 , 2, 3, 9} .

[00132] In some embodiments, in procedure 4, the UE 1004 may transmit the SRS symbols with K2 beams in N2 symbols. Thus, as the prior beam indicator is 1 in the DCI 1020, the UE 1004 may transmit the K2 beams around the selected beam 2.

[00133] In some embodiments, the DCI 1020 may also identify the numbers K2 and

N2, such that the UE 1004 may transmit the K2 beams in N2 SRS symbols.

[00134] In some embodiments, in procedure 4.5, the eNB 1002 may select an appropriate beam 1024 (e.g., a beast beam, an optimal beam, a near optimal beam, the beam having a highest power level, the beam having power level higher than a threshold, etc.) from the beam set K2, e.g., by comparing the received signal power of the beams 1 , 2, 3, and 9 in the set K2.

[00135] In some embodiments, in procedure 5, the eNB 1002 may transmit an index of the selected beam 1024 to the UE 1004 via, for example, DCI 1028. The selected beam 1024 may be the beam that the UE 1004 may use for UL transmissions.

[00136] Thus, Fig. 10 illustrates a two-step process. In the first step, the candidate UL beams in the set Kl are compared and an appropriate beam 1016 from the set Kl is selected by the eNB 1002. The first step is somewhat analogous to a coarse selection of a candidate UL beam. The first step comprises procedures 1 and 2 of Fig. 10. [00137] In the second step, a finer selection of a UL beam is performed. For example, beams neighboring the selected beam are now included in the set K2, and a final beam 1024 from the set K2 is selected. The final selected beam may be used by the UE 1004 for UL transmissions. The second step is somewhat analogous to a finer selection of a candidate UL beam. The second step comprises procedures 3-5 of Fig. 10.

[00138] In some embodiments, the system 1000 may perform both the first and second steps, e.g., perform procedures 1-5. In some other embodiments, the system 1000 may stop at the first step (e.g., stop after the procedure 2), and use the beam 1016 selected at the first step.

[00139] Fig. 13 illustrates an eNB and a UE, according to some embodiments. Fig. 13 includes block diagrams of an eNB 1310 and a UE 1330 which are operable to co-exist with each other and other elements of an LTE network. High-level, simplified architectures of eNB 1310 and UE 1330 are described so as not to obscure the embodiments. It should be noted that in some embodiments, eNB 1310 may be a stationary non-mobile device. In some embodiments, the UE 1330 of Fig. 13 may correspond to any UE discussed herein.

[00140] In some embodiments, the eNB 1310 is coupled to one or more antennas 1305, and UE 1330 is similarly coupled to one or more antennas 1325. However, in some embodiments, eNB 1310 may incorporate or comprise antennas 1305, and UE 1330 in various embodiments may incorporate or comprise antennas 1325.

[00141] In some embodiments, antennas 1305 and/or antennas 1325 may comprise one or more directional or omni-directional antennas, including monopole antennas, dipole antennas, loop antennas, patch antennas, microstrip antennas, coplanar wave antennas, or other types of antennas suitable for transmission of RF signals. In some MIMO (multiple- input and multiple output) embodiments, antennas 1305 are separated to take advantage of spatial diversity.

[00142] eNB 1310 and UE 1330 are operable to communicate with each other on a network, such as a wireless network (e.g., using licensed or unlicensed spectrum). eNB 1310 and UE 1330 may be in communication with each other over a wireless communication channel 1350, which has both a downlink path from eNB 1310 to UE 1330 and an Uplink path from UE 1330 to eNB 1310.

[00143] As illustrated in Fig. 13, in some embodiments, eNB 1310 may include a physical layer circuitry 1312, a MAC (media access control) circuitry 1314, a processor 1316, a memory 1318, and a hardware processing circuitry 1320. A person skilled in the art will appreciate that other components not shown may be used in addition to the components shown to form a complete eNB.

[00144] In some embodiments, physical layer circuitry 1312 includes a transceiver

1313 for providing signals to and from UE 1330. Transceiver 1313 provides signals to and from UEs or other devices using one or more antennas 1305. In some embodiments, MAC circuitry 1314 controls access to the wireless medium. Memory 1318 may be, or may include, a storage media/medium such as a magnetic storage media (e.g., magnetic tapes or magnetic disks), an optical storage media (e.g., optical discs), an electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash-memory-based storage media), or any tangible storage media or non-transitory storage media. Hardware processing circuitry 1320 may comprise logic devices or circuitry to perform various operations. In some embodiments, processor 1316 and memory 1318 are arranged to perform the operations of hardware processing circuitry 1320, such as operations described herein with reference to logic devices and circuitry within eNB 1310 and/or hardware processing circuitry 1320.

[00145] Accordingly, in some embodiments, eNB 1310 may be a device comprising an application processor, a memory, one or more antenna ports, and an interface for allowing the application processor to communicate with another device.

[00146] As is also illustrated in Fig. 13, in some embodiments, UE 1330 may include a physical layer circuitry 1332, a MAC circuitry 1334, a processor 1336, a memory 1338, a hardware processing circuitry 1340, a wireless interface 1342, and a display 1344. A person skilled in the art would appreciate that other components not shown may be used in addition to the components shown to form a complete UE.

[00147] In some embodiments, physical layer circuitry 1332 includes a transceiver

1333 for providing signals to and from eNB 1310 (as well as other eNBs). Transceiver 1333 provides signals to and from eNBs or other devices using one or more antennas 1325. In some embodiments, MAC circuitry 1334 controls access to the wireless medium. Memory 1338 may be, or may include, a storage media/medium such as a magnetic storage media (e.g., magnetic tapes or magnetic disks), an optical storage media (e.g., optical discs), an electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any tangible storage media or non-transitory storage media. Wireless interface 1342 may be arranged to allow the processor to communicate with another device. Display 1344 may provide a visual and/or tactile display for a user to interact with UE 1330, such as a touch-screen display. Hardware processing circuitry 1340 may comprise logic devices or circuitry to perform various operations. In some embodiments, processor 1336 and memory 1338 may be arranged to perform the operations of hardware processing circuitry 1340, such as operations described herein with reference to logic devices and circuitry within UE 1330 and/or hardware processing circuitry 1340.

[00148] Accordingly, in some embodiments, UE 1330 may be a device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display.

[00149] Elements of Fig. 13, and elements of other figures having the same names or reference numbers, can operate or function in the manner described herein with respect to any such figures (although the operation and function of such elements is not limited to such descriptions). For example, Figs. 1-12 also depict embodiments of eNBs, hardware processing circuitry of eNBs, UEs, and/or hardware processing circuitry of UEs, and the embodiments described with respect to Figs. 1-12 can operate or function in the manner described herein with respect to any of the figures.

[00150] In addition, although eNB 1310 and UE 1330 are each described as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements and/or other hardware elements. In some embodiments of this disclosure, the functional elements can refer to one or more processes operating on one or more processing elements. Examples of software and/or hardware configured elements include Digital Signal Processors (DSPs), one or more microprocessors, DSPs, Field-Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Radio-Frequency Integrated Circuits (RFICs), and so on.

[00151] Fig. 14 illustrates hardware processing circuitries for an eNB that selects an

UL beam for UL transmissions, according to some embodiments. With reference to Fig. 13, an eNB may include various hardware processing circuitries discussed below, which may in turn comprise logic devices and/or circuitry operable to perform various operations. For example, in Fig. 13, eNB 1310 (or various elements or components therein, such as hardware processing circuitry 1320, or combinations of elements or components therein) may include part of, or all of, these hardware processing circuitries.

[00152] In some embodiments, one or more devices or circuitries within these hardware processing circuitries may be implemented by combinations of software-configured elements and/or other hardware elements. For example, processor 1316 (and/or one or more other processors which eNB 1310 may comprise), memory 1318, and/or other elements or components of eNB 1310 (which may include hardware processing circuitry 1320) may be arranged to perform the operations of these hardware processing circuitries, such as operations described herein with reference to devices and circuitry within these hardware processing circuitries. In some embodiments, processor 1316 (and/or one or more other processors which eNB 1310 may comprise) may be a baseband processor.

[00153] Returning to Fig. 14, an apparatus of eNB 1310 (or another eNB or base station), which may be operable to communicate with one or more UEs on a wireless network, may comprise hardware processing circuitry 1400. In some embodiments, hardware processing circuitry 1400 may comprise one or more antenna ports 1405 operable to provide various transmissions over a wireless communication channel (such as wireless

communication channel 1350). Antenna ports 1405 may be coupled to one or more antennas 1407 (which may be antennas 1305). In some embodiments, hardware processing circuitry 1400 may incorporate antennas 1407, while in other embodiments, hardware processing circuitry 1400 may merely be coupled to antennas 1407.

[00154] Antenna ports 1405 and antennas 1407 may be operable to provide signals from an eNB to a wireless communications channel and/or a UE, and may be operable to provide signals from a UE and/or a wireless communications channel to an eNB. For example, antenna ports 1405 and antennas 1407 may be operable to provide transmissions from eNB 1310 to wireless communication channel 1350 (and from there to UE 1330, or to another UE). Similarly, antennas 1407 and antenna ports 1405 may be operable to provide transmissions from a wireless communication channel 1350 (and beyond that, from UE 1330, or another UE) to eNB 1310.

[00155] Hardware processing circuitry 1400 may comprise various circuitries operable in accordance with the various embodiments discussed herein. With reference to Fig. 14, hardware processing circuitry 1400 may comprise a first circuitry 1410, a second circuitry 1420, and a third circuitry 1430.

[00156] In some embodiments, the first circuitry 1410 may be operable to process first

UL signals received over a first plurality of UL beams (e.g., beams in the set Kl discussed with respect to Fig. 10) from the UE. The second circuitry 1420 may be operable to select a first UL beam from the first plurality of UL beams. The third circuitry 1430 may be operable to initiate transmission of an identification of the selected first UL beam to the UE, wherein the UE is to select a second plurality of UL beams based on the identification of the first UL beam. The first circuitry 1410 may be further operable to process second UL signals received over the second plurality of UL beams (e.g., beams in the set K2 discussed with respect to Fig. 10) from the UE. The first circuitry 1420 may be further operable to select a second UL beam from the second plurality of UL beams. The first circuitry 1410 may be operable to initiate transmission of an identification of the selected second UL beam to the UE (e.g., procedure 5 of Fig. 10), wherein the UE may transmit UL signals over the second beam.

[00157] In some embodiments, the first uplink (UL) signals may comprise SRS symbols transmitted over the first plurality of UL beams. In some embodiments, to initiate transmission of the identification of the selected first UL beam to the UE, the eNB may initiate transmission of a DCI (e.g., DCI 1020), the DCI comprising one of: a beam index corresponding to the selected first beam, or an identification of a first SRS symbol of the first UL signals (e.g., as discussed with respect to table 2), wherein the first SRS is received over the selected first beam. In some embodiments, a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD (e.g., as discussed with respect to Fig. 12), the second plurality of UL being a subset of the plurality of candidate UL beams. In some embodiments, the first plurality of UL beams are mapped substantially evenly across the space of the AoD and the ZoD of the UE (e.g., as discussed with respect to Fig. 11); and the first plurality of UL beams are another subset of the plurality of candidate UL beams. In some embodiments, the eNB may initiate transmission of a first number and a second number to the UE, wherein the UE is to transmit the first number of beams in the second number of Sounding Reference Signal (SRS) symbols to the UE.

[00158] In some embodiments, hardware processing circuitry 1400 may be coupled to a transceiver circuitry for at least one of: processing UL signals, selecting first and second UL beams transmissions, etc.

[00159] In some embodiments, first circuitry 1410, second circuitry 1420, and/or third circuitry 1430 may be implemented as separate circuitries. In other embodiments, first circuitry 1410, second circuitry 1420 and/or third circuitry 1430 may be combined and implemented together in a circuitry without altering the essence of the embodiments.

[00160] Fig. 15 illustrates hardware processing circuitries for a UE to generate a precoding matrix for beamforming, based on downlink signals, according to some embodiments. With reference to Fig. 13, a UE may include various hardware processing circuitries discussed below, which may in turn comprise logic devices and/or circuitry operable to perform various operations. For example, in Fig. 13, UE 1330 (or various elements or components therein, such as hardware processing circuitry 1340, or combinations of elements or components therein) may include part of, or all of, these hardware processing circuitries.

[00161] In some embodiments, one or more devices or circuitries within these hardware processing circuitries may be implemented by combinations of software-configured elements and/or other hardware elements. For example, processor 1336 (and/or one or more other processors which UE 1330 may comprise), memory 1338, and/or other elements or components of UE 1330 (which may include hardware processing circuitry 1340) may be arranged to perform the operations of these hardware processing circuitries, such as operations described herein with reference to devices and circuitry within these hardware processing circuitries. In some embodiments, processor 1336 (and/or one or more other processors which UE 1330 may comprise) may be a baseband processor.

[00162] Returning to Fig. 15, an apparatus of UE 1330 (or another UE or mobile handset), which may be operable to communicate with one or more eNBs on a wireless network, may comprise hardware processing circuitry 1500. In some embodiments, hardware processing circuitry 1500 may comprise one or more antenna ports 1505 operable to provide various transmissions over a wireless communication channel (such as wireless

communication channel 1350). Antenna ports 1505 may be coupled to one or more antennas 1507 (which may be antennas 1325). In some embodiments, hardware processing circuitry 1500 may incorporate antennas 1507, while in other embodiments, hardware processing circuitry 1500 may merely be coupled to antennas 1507.

[00163] Antenna ports 1505 and antennas 1507 may be operable to provide signals from a UE to a wireless communications channel and/or an eNB, and may be operable to provide signals from an eNB and/or a wireless communications channel to a UE. For example, antenna ports 1505 and antennas 1507 may be operable to provide transmissions from UE 1330 to wireless communication channel 1350 (and from there to eNB 1310, or to another eNB). Similarly, antennas 1507 and antenna ports 1505 may be operable to provide transmissions from a wireless communication channel 1350 (and beyond that, from eNB 1310, or another eNB) to UE 1330.

[00164] Hardware processing circuitry 1500 may comprise various circuitries operable in accordance with the various embodiments discussed herein. With reference to Fig. 15, hardware processing circuitry 1500 may comprise a first circuitry 1510, a second circuitry 1520, and/or a third circuitry 1530.

[00165] In some embodiments, first circuitry 1510 may be operable to process downlink signals received from the eNB, as discussed with respect to Fig. 1-4. Second circuitry 1520 may be operable to determine a precoding matrix for uplink transmission, based on processing the downlink signals.

[00166] In some embodiments, to determine the precoding matrix, the DCI received from the eNB may be processed, the DCI comprising a RI associated with the precoding matrix, and the precoding matrix may be determined based on the RI. In some embodiments, the downlink signals may comprise BRS; eigenvectors associated with a channel between the eNB and the UE may be estimated, based on processing the BRS; and the precoding matrix may be determined based on the estimated eigenvector. In some embodiments, an UL grant from the eNB may be processed, the UL grant comprising a BRS index identifying a BRS sequence; and the precoding matrix may be determined based on the BRS index. In some embodiments, a BRS-RP report may be generated for transmission to the eNB, the BRS-RP report identifying a first uplink beam that the UE has determined to be appropriate for UL transmission. In some embodiments, a SRS may be generated for transmission to the eNB, the SRS to be transmitted in the first uplink beam identified in the BRS-RP. In some embodiments, the downlink signals may comprise CSI-RS; Eigen Vectors associated with a channel between the eNB and the UE may be estimated based on processing the CSI-RS; and the precoding matrix may be determined, based on the estimated Eigen Vector. In some embodiments, an UL grant from the eNB may be processed, the UL grant comprising a CRI; and the precoding matrix may be determined, based on the CRI. In some embodiments, the CRI may be received via Downlink Control Information (DCI) signal. In some

embodiments, a CSI report may be generated for transmission to the eNB, the CSI report identifying a first uplink beam that the UE has determined to be appropriate for UL transmission; and a SRS may be generated for transmission to the eNB, the SRS to be transmitted in the first uplink beam identified in the CSI report. In some embodiments, a Physical Uplink Shared Channel (PUSCH) signal or a 5G Physical Uplink Shared Channel (xPUSCH) signal may be generated for transmission to the eNB, in accordance with the precoding matrix.

[00167] In some embodiments, first circuitry 1510 and/or second circuitry 1520 may be implemented as separate circuitries. In other embodiments, first circuitry 1510 and second circuitry 1520 may be combined and implemented together in a circuitry without altering the essence of the embodiments.

[00168] Fig. 16 illustrates a method 1600 for a UE to generate a precoding matrix for beamforming, based on downlink signals, according to some embodiments. With reference to Fig. 13, the method 1600 that may relate to UE 1330 and hardware processing circuitry 1340 are discussed below. Although the actions in the method of Fig. 16 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 16 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must

occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00169] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause UE 1330 and/or hardware processing circuitry 1340 to perform an operation comprising the method of Fig. 16. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any other tangible storage media or non-transitory storage media.

[00170] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the method 1600 of Fig. 16.

[00171] Returning to Fig. 16, the method 1600 may be in accordance with the various embodiments discussed herein. The method 1600 may comprise, at 1604, processing downlink signals received from the eNB, e.g., as discussed with respect to Figs. 1-4. At 1608, a precoding matrix for uplink transmission may be determined, e.g., based on processing the downlink signals.

[00172] In some embodiments, to determine the precoding matrix, the DCI received from the eNB may be processed, the DCI comprising a RI associated with the precoding matrix, and the precoding matrix may be determined based on the RI. In some embodiments, the downlink signals may comprise BRS; Eigen Vectors associated with a channel between the eNB and the UE may be estimated, based on processing the BRS; and the precoding matrix may be determined based on the estimated Eigen Vector. In some embodiments, an UL grant from the eNB may be processed, the UL grant comprising a BRS index identifying a BRS sequence; and the precoding matrix may be determined based on the BRS index. In some embodiments, a BRS-RP report may be generated for transmission to the eNB, the BRS-RP report identifying a first uplink beam that the UE has determined to be appropriate for UL transmission. In some embodiments, a SRS may be generated for transmission to the eNB, the SRS to be transmitted in the first uplink beam identified in the BRS-RP. In some embodiments, the downlink signals may comprise CSI-RS; Eigen Vectors associated with a channel between the eNB and the UE may be estimated based on processing the CSI-RS; and the precoding matrix may be determined, based on the estimated Eigen Vector. In some embodiments, an UL grant from the eNB may be processed, the UL grant comprising a CRI; and the precoding matrix may be determined, based on the CRI. In some embodiments, the CRI may be received via Downlink Control Information (DCI) signal. In some

[00173] Fig. 17 illustrates a method 1700 for a eNB to select an UL beam for UL transmissions, according to some embodiments. With reference to Fig. 13, the method 1700 that may relate to eNB 1310 and hardware processing circuitry 1320 are discussed below. Although the actions in the method 1700 of Fig. 17 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 17 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00174] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause eNB 1310 and/or hardware processing circuitry 1320 to perform an operation comprising the method 1700 of Fig. 17. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or fiash-memory-based storage media), or any other tangible storage media or non-transitory storage media.

[00175] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the method 1700 of Fig. 17. [00176] Returning to Fig. 17, various methods may be in accordance with the various embodiments discussed herein. A method 1700 may comprise, at 1704, processing first uplink (UL) signals received over a first plurality of UL beams from a UE (e.g., UE 1004 of Fig. 10). The first plurality of UL beams may be beams included in the set Kl, as discussed with respect to Figs. 10-12.

[00177] The method 1700 may comprise, at 1708, selecting a first UL beam (e.g., beam 1016) from the first plurality of UL beams, e.g., as discussed with respect to procedure 2.5 of Fig. 10. The method 1700 may comprise, at 1712, initiating transmission of an identification of the selected first UL beam to the UE. For example, the identification of the selected first UL beam may be transmitted to the UE via the DCI 1020 of Fig. 10. In some embodiments, the UE may select a second plurality of UL beams (e.g., beams in the set K2) based on the identification of the first UL beam.

[00178] The method 1700 may comprise, at 1716, processing second UL signals received over the second plurality of UL beams from the UE, e.g., as discussed with respect to procedures 4 and 4.5 of Fig. 10. The method 1700 may comprise, at 1720, selecting a second UL beam (e.g., beam 1024) from the second plurality of UL beams.

[00179] In some embodiments, the eNB may initiate transmission of an identification of the selected second UL beam to the UE (e.g., procedure 5 of Fig. 10), wherein the UE may transmit UL signals over the second beam. In some embodiments, the first uplink (UL) signals comprise Sounding Reference Signal (SRS) symbols transmitted over the first plurality of UL beams. In some embodiments, to initiate transmission of the identification of the selected first UL beam to the UE, the eNB may initiate transmission of a DCI (e.g., DCI 1020), the DCI comprising one of: a beam index corresponding to the selected first beam, or an identification of a first SRS symbol of the first UL signals (e.g., as discussed with respect to table 2), wherein the first SRS is received over the selected first beam. In some embodiments, a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD (e.g., as discussed with respect to Fig. 12), the second plurality of UL being a subset of the plurality of candidate UL beams. In some embodiments, the first plurality of UL beams are mapped substantially evenly across the space of the AoD and the ZoD of the UE (e.g., as discussed with respect to Fig. 11); and the first plurality of UL beams are another subset of the plurality of candidate UL beams. In some embodiments, the eNB may initiate transmission of a first number and a second number to the UE, wherein the UE is to transmit the first number of beams in the second number of Sounding Reference Signal (SRS) symbols to the UE.

[00180] Fig. 18 illustrates an architecture of a system 1800 of a network in accordance with some embodiments. The system 1800 is shown to include a user equipment (UE) 1801 and a UE 1802. The UEs 1801 and 1802 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless communications interface.

[00181] In some embodiments, any of the UEs 1801 and 1802 can comprise an Internet of Things (IoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity -Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived

connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

[00182] The UEs 1801 and 1802 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN)— in this embodiment, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) 1810. The UEs 1801 and 1802 utilize connections 1803 and 1804, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 1803 and 1804 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code- division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and the like.

[00183] In this embodiment, the UEs 1801 and 1802 may further directly exchange communication data via a ProSe interface 1805. The ProSe interface 1805 may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

[00184] The UE 1802 is shown to be configured to access an access point (AP) 1806 via connection 1807. The connection 1807 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 1806 would comprise a wireless fidelity (WiFi®) router. In this example, the AP 1806 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below).

[00185] The E-UTRAN 1810 can include one or more access nodes that enable the connections 1803 and 1804. These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), nel9 Generation NodeBs (gNB), RAN nodes, and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). The E-UTRAN 1810 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 1811, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 1812.

[00186] Any of the RAN nodes 1811 and 1812 can terminate the air interface protocol and can be the first point of contact for the UEs 1801 and 1802. In some embodiments, any of the RAN nodes 1811 and 1812 can fulfill various logical functions for the E-UTRAN 1810 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

[00187] In accordance with some embodiments, the UEs 1801 and 1802 can be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes 1811 and 1812 over a multicarrier communication channel in accordance various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers. [00188] In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 1811 and 1812 to the UEs 1801 and 1802, while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

[00189] The physical downlink shared channel (PDSCH) may carry user data and higher-layer signaling to the UEs 1801 and 1802. The physical downlink control channel (PDCCH) may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 1801 and 1802 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 1802 within a cell) may be performed at any of the RAN nodes 1811 and 1812 based on channel quality information fed back from any of the UEs 1801 and 1802. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs 1801 and 1802.

[00190] The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub- block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8). [00191] Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more enhanced the control channel elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an enhanced resource element groups (EREGs). An ECCE may have other numbers of EREGs in some situations.

[00192] The E-UTRAN 1810 is shown to be communicatively coupled to a core network— in this embodiment, an Evolved Packet Core (EPC) network 1820 via an S I interface 1813. In this embodiment the SI interface 1813 is split into two parts: the S l-U interface 1814, which carries traffic data between the RAN nodes 1811 and 1812 and the serving gateway (S-GW) 1822, and the SI -mobility management entity (MME) interface 1815, which is a signaling interface between the RAN nodes 1811 and 1812 and MMEs 1821.

[00193] In this embodiment, the EPC network 1820 comprises the MMEs 1821, the S-

GW 1822, the Packet Data Network (PDN) Gateway (P-GW) 1823, and a home subscriber server (HSS) 1824. The MMEs 1821 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 1821 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 1824 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The EPC network 1820 may comprise one or several HSSs 1824, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 1824 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

[00194] The S-GW 1822 may terminate the S 1 interface 1813 towards the E-UTRAN

1810, and routes data packets between the E-UTRAN 1810 and the EPC network 1820. In addition, the S-GW 1822 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement.

[00195] The P-GW 1823 may terminate an SGi interface toward a PDN. The P-GW

1823 may route data packets between the EPC network 1823 and extemal networks such as a network including the application server 1830 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 1825. Generally, the application server 1830 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW 1823 is shown to be communicatively coupled to an application server 1830 via an IP communications interface 1825. The application server 1830 can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 1801 and 1802 via the EPC network 1820.

[00196] The P-GW 1823 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) 1826 is the policy and charging control element of the EPC network 1820. In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 1826 may be communicatively coupled to the application server 1830 via the P-GW 1823. The application server 1830 may signal the PCRF 1826 to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF 1826 may provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate traffic flow template (TFT) and QoS class of identifier (QCI), which commences the QoS and charging as specified by the application server 1830.

[00197] Fig. 19 illustrates example components of a device 1900 in accordance with some embodiments. In some embodiments, the device 1900 may include application circuitry 1902, baseband circuitry 1904, Radio Frequency (RF) circuitry 1906, front-end module (FEM) circuitry 1908, one or more antennas 1910, and power management circuitry (PMC) 1912 coupled together at least as shown. The components of the illustrated device 1900 may be included in a UE or a RAN node. In some embodiments, the device 1900 may include less elements (e.g., a RAN node may not utilize application circuitry 1902, and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device 1900 may include additional elements such as, for example, memory /storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C- RAN) implementations).

[00198] The application circuitry 1902 may include one or more application processors. For example, the application circuitry 1902 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory /storage and may be configured to execute instructions stored in the memory /storage to enable various applications or operating systems to run on the device 1900. In some embodiments, processors of application circuitry 1902 may process IP data packets received from an EPC.

[00199] The baseband circuitry 1904 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 1904 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 1906 and to generate baseband signals for a transmit signal path of the RF circuitry 1906. Baseband processing circuity 1904 may interface with the application circuitry 1902 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 1906. For example, in some embodiments, the baseband circuitry 1904 may include a third generation (3G) baseband processor 1904A, a fourth generation (4G) baseband processor 1904B, a fifth generation (5G) baseband processor 1904C, or other baseband processor(s) 1904D for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry 1904 (e.g., one or more of baseband processors 1904A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 1906. In other embodiments, some or all of the functionality of baseband processors 1904A-D may be included in modules stored in the memory 1904G and executed via a Central Processing Unit (CPU) 1904E. The radio control functions may include, but are not limited to, signal modulation/demodulation,

encoding/decoding, radio frequency shifting, etc. In some embodiments,

modulation/demodulation circuitry of the baseband circuitry 1904 may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 1904 may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[00200] In some embodiments, the baseband circuitry 1904 may include one or more audio digital signal processor(s) (DSP) 1904F. The audio DSP(s) 1904F may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 1904 and the application circuitry 1902 may be implemented together such as, for example, on a system on a chip (SOC).

[00201] In some embodiments, the baseband circuitry 1904 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 1904 may support communication with an evolved universal terrestrial radio access network (EUTRAN) or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 1904 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[00202] RF circuitry 1906 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 1906 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 1906 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 1908 and provide baseband signals to the baseband circuitry 1904. RF circuitry 1906 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 1904 and provide RF output signals to the FEM circuitry 1908 for transmission.

[00203] In some embodiments, the receive signal path of the RF circuitry 1906 may include mixer circuitry 1906a, amplifier circuitry 1906b and filter circuitry 1906c. In some embodiments, the transmit signal path of the RF circuitry 1906 may include filter circuitry 1906c and mixer circuitry 1906a. RF circuitry 1906 may also include synthesizer circuitry 1906d for synthesizing a frequency for use by the mixer circuitry 1906a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 1906a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 1908 based on the synthesized frequency provided by synthesizer circuitry 1906d. The amplifier circuitry 1906b may be configured to amplify the down-converted signals and the filter circuitry 1906c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 1904 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 1906a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[00204] In some embodiments, the mixer circuitry 1906a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 1906d to generate RF output signals for the FEM circuitry 1908. The baseband signals may be provided by the baseband circuitry 1904 and may be filtered by filter circuitry 1906c.

[00205] In some embodiments, the mixer circuitry 1906a of the receive signal path and the mixer circuitry 1906a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry 1906a of the receive signal path and the mixer circuitry 1906a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 1906a of the receive signal path and the mixer circuitry 1906a may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry 1906a of the receive signal path and the mixer circuitry 1906a of the transmit signal path may be configured for super-heterodyne operation.

[00206] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 1906 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 1904 may include a digital baseband interface to communicate with the RF circuitry 1906.

[00207] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect. [00208] In some embodiments, the synthesizer circuitry 1906d may be a fractional -N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 1906d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[00209] The synthesizer circuitry 1906d may be configured to synthesize an output frequency for use by the mixer circuitry 1906a of the RF circuitry 1906 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 1906d may be a fractional N/N+l synthesizer.

[00210] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 1904 or the applications processor 1902 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 1902.

[00211] Synthesizer circuitry 1906d of the RF circuitry 1906 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[00212] In some embodiments, synthesizer circuitry 1906d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 1906 may include an IQ/polar converter. [00213] FEM circuitry 1908 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 1910, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 1906 for further processing. FEM circuitry 1908 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 1906 for transmission by one or more of the one or more antennas 1910. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry 1906, solely in the FEM 1908, or in both the RF circuitry 1906 and the FEM 1908.

[00214] In some embodiments, the FEM circuitry 1908 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 1906). The transmit signal path of the FEM circuitry 1908 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 1906), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 1910).

[00215] In some embodiments, the PMC 1912 may manage power provided to the baseband circuitry 1904. In particular, the PMC 1912 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC 1912 may often be included when the device 1900 is capable of being powered by a battery, for example, when the device is included in a UE. The PMC 1912 may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics.

[00216] While Fig. 19 shows the PMC 1912 coupled only with the baseband circuitry 1904. However, in other embodiments, the PMC 1912 may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry 1902, RF circuitry 1906, or FEM 1908.

[00217] In some embodiments, the PMC 1912 may control, or otherwise be part of, various power saving mechanisms of the device 1900. For example, if the device 1900 is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device 1900 may power down for brief intervals of time and thus save power. [00218] If there is no data traffic activity for an extended period of time, then the device 1900 may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device 1900 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device 1900 may not receive data in this state, in order to receive data, it must transition back to RRC Connected state.

[00219] An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

[00220] Processors of the application circuitry 1902 and processors of the baseband circuitry 1904 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 1904, alone or in combination, may be used execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry 1904 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below.

[00221] Fig. 20 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry 1904 of Fig. 19 may comprise processors 1904A-1904E and a memory 1904G utilized by said processors. Each of the processors 1904A-1904E may include a memory interface, 2004A-2004E, respectively, to send/receive data to/from the memory 1904G.

[00222] The baseband circuitry 1904 may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface 2012 (e.g., an interface to send/receive data to/from memory extemal to the baseband circuitry 1904), an application circuitry interface 2014 (e.g., an interface to send/receive data to/from the application circuitry 1902 of Fig. 19), an RF circuitry interface 2016 (e.g., an interface to send/receive data to/from RF circuitry 1906 of Fig. 19), a wireless hardware connectivity interface 2018 (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface 2020 (e.g., an interface to send/receive power or control signals to/from the PMC 1912.

[00223] Reference in the specification to "an embodiment," "one embodiment," "some embodiments," or "other embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments. The various appearances of "an embodiment," "one embodiment," or "some embodiments" are not necessarily all referring to the same embodiments. If the specification states a component, feature, structure, or characteristic "may," "might," or "could" be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to "a" or "an" element, that does not mean there is only one of the elements. If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.

[00224] Furthermore, the particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more embodiments. For example, a first embodiment may be combined with a second embodiment anywhere the particular features, structures, functions, or characteristics associated with the two embodiments are not mutually exclusive.

[00225] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of such embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description. For example, other memory architectures e.g., Dynamic RAM (DRAM) may use the

embodiments discussed. The embodiments of the disclosure are intended to embrace all such alternatives, modifications, and variations as to fall within the broad scope of the appended claims.

[00226] In addition, well known power/ground connections to integrated circuit (IC) chips and other components may or may not be shown within the presented figures, for simplicity of illustration and discussion, and so as not to obscure the disclosure. Further, arrangements may be shown in block diagram form in order to avoid obscuring the disclosure, and also in view of the fact that specifics with respect to implementation of such block diagram arrangements are highly dependent upon the platform within which the present disclosure is to be implemented (i.e., such specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that the disclosure can be practiced without, or with variation of, these specific details. The description is thus to be regarded as illustrative instead of limiting.

[00227] The following examples pertain to further embodiments. Specifics in the examples may be used anywhere in one or more embodiments. All optional features of the apparatus described herein may also be implemented with respect to a method or process.

[00228] Example 1. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: one or more processors to: process Downlink (DL) signals received from the eNB, and determine a precoding matrix for Uplink (UL) transmission, based on processing the DL signals; and an interface to receive the DL signals.

[00229] Example 2. The apparatus of example 1 , wherein to determine the precoding matrix, the one or more processors are to: process a Downlink Control Information (DCI) received from the eNB, the DCI comprising a Rank Indicator (RI) associated with the precoding matrix; and determine the precoding matrix, based on the RI.

[00230] Example 3. The apparatus of example 1 , wherein the DL signals comprise a

Beam Reference Signal (BRS), and wherein to determine the precoding matrix, the one or more processors are to: estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the BRS; and determine the precoding matrix, based on the estimated eigenvectors.

[00231] Example 4. The apparatus of example 1 , wherein to determine the precoding matrix, the one or more processors are to: process a UL grant from the eNB, the UL grant comprising a Beam Reference Signal (BRS) index identifying a BRS sequence; and determine the precoding matrix, based on the BRS index.

[00232] Example 5. The apparatus of any of examples 1-4, wherein the one or more are processors to: generate, for transmission to the eNB, a Beam Reference Signal Receiving Power (BRS-RP) report, the BRS-RP report identifying a first UL beam that the UE has determined to be appropriate for UL transmission.

[00233] Example 6. The apparatus of example 5, wherein the one or more are processors to: generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the BRS-RP report. [00234] Example 7. The apparatus of example 1, wherein the DL signals comprise a

Channel State Information Reference Signal (CSI-RS), and wherein to determine the precoding matrix, the one or more processors are to: estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the CSI-RS; and determine the precoding matrix, based on the estimated eigenvectors.

[00235] Example 8. The apparatus of example 1, wherein to determine the precoding matrix, the one or more processors are to: process a UL grant from the eNB, the UL grant comprising a Channel State Information Reference Signal Resource index (CRI); and determine the precoding matrix, based on the CRI.

[00236] Example 9. The apparatus of example 8, wherein the CRI is received via

Downlink Control Information (DCI) signaling.

[00237] Example 10. The apparatus of any of examples 1 and 7-9, wherein the one or more are processors to: generate, for transmission to the eNB, a Channel State Information (CSI) report, the CSI report identifying a first UL beam that the UE has determined to be appropriate for UL transmission; and generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the CSI report.

[00238] Example 11. The apparatus of any of examples 1-10, wherein the one or more are processors to: generate, for transmission to the eNB, a Physical Uplink Shared Channel (PUSCH) signal or a 5G PUSCH (xPUSCH) signal, in accordance with the precoding matrix.

[00239] Example 12. The apparatus of any of examples 1 to 11 , comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00240] Example 13. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of examples 1 to 12.

[00241] Example 14. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: process Downlink (DL) signals received from an Evolved Node B (eNB); and determine a precoding matrix for Uplink (UL) transmission, based on processing the DL signals.

[00242] Example 15. The machine readable storage media of example 14, wherein to determine the precoding matrix, the operation comprises: process a Downlink Control Information (DCI) received from the eNB, the DCI comprising a Rank Indicator (RI) associated with the precoding matrix; and determine the precoding matrix, based on the RI.

[00243] Example 16. The machine readable storage media of example 14, wherein the

DL signals comprise a Beam Reference Signal (BRS), and wherein to determine the precoding matrix, the operation comprises: estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the BRS; and determine the precoding matrix, based on the estimated eigenvectors.

[00244] Example 17. The machine readable storage media of example 14, wherein to determine the precoding matrix, the operation comprises: process a UL grant from the eNB, the UL grant comprising a Beam Reference Signal (BRS) index identifying a BRS sequence; and determine the precoding matrix, based on the BRS index.

[00245] Example 18. The machine readable storage media of any of examples 14-17, wherein the operation comprises: generate, for transmission to the eNB, a Beam Reference Signal Receiving Power (BRS-RP) report, the BRS-RP report identifying a first UL beam that the UE has determined to be appropriate for UL transmission.

[00246] Example 19. The machine readable storage media of example 18, wherein the operation comprises: generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the BRS-RP report.

[00247] Example 20. The machine readable storage media of example 14, wherein the

DL signals comprise Channel State Information Reference Signal (CSI-RS), and wherein to determine the precoding matrix, the operation comprises: estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the CSI-RS; and determine the precoding matrix, based on the estimated eigenvectors.

[00248] Example 21. The machine readable storage media of example 14, wherein to determine the precoding matrix, the operation comprises: process a UL grant from the eNB, the UL grant comprising a Channel State Information Reference Signal Resource index (CRI); and determine the precoding matrix, based on the CRI.

[00249] Example 22. The machine readable storage media of example 21, wherein the

CRI is received via Downlink Control Information (DCI) signaling.

[00250] Example 23. The machine readable storage media of any of examples 14 and

20-22, the operation comprising: generate, for transmission to the eNB, a Channel State Information (CSI) report, the CSI report identifying a first UL beam that the UE has determined to be appropriate for UL transmission; and generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the CSI report.

[00251] Example 24. The machine readable storage media of any of examples 14-23, the operation comprising: generate, for transmission to the eNB, a Physical Uplink Shared Channel (PUSCH) signal or a 5G PUSCH (xPUSCH) signal, in accordance with the precoding matrix.

[00252] Example 25. An apparatus of an Evolved Node B (eNB) operable to communicate with a User Equipment (UE) on a wireless network, comprising: one or more processors to: process one or more first Uplink (UL) signals received over a first plurality of UL beams from the UE, select a first UL beam from the first plurality of UL beams, initiate transmission of an identification of the selected first UL beam to the UE, wherein the UE is to select a second plurality of UL beams based on the identification of the first UL beam, process one or more second UL signals received over the second plurality of UL beams from the UE, and select a second UL beam from the second plurality of UL beams; and an interface to receive the one or more first UL signals.

[00253] Example 26. The apparatus of example 25, wherein the one or more are processors to: initiate transmission of an identification of the selected second UL beam to the

UE, wherein the UE is to transmit UL signals over the second beam.

[00254] Example 27. The apparatus of example 25, wherein the first UL signals comprise Sounding Reference Signal (SRS) symbols transmitted over the first plurality of UL beams.

[00255] Example 28. The apparatus of any of examples 25-27, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the one or more are processors to: initiate transmission of a Downlink Control Information (DO), the DCI comprising at least one of: a beam index corresponding to the selected first beam, or an identification of a first Sounding Reference Signal (SRS) symbol of the first UL signals, wherein the first SRS is received over the selected first beam.

[00256] Example 29. The apparatus of any of examples 25-27, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the one or more are processors to: initiate transmission of a Downlink Control Information (DCI), the DCI comprising a prior beam indicator that is to identify the selected first UL beam to the UE.

[00257] Example 30. The apparatus of any of examples 25-27, wherein: a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD, the second plurality of UL beams being a subset of the plurality of candidate UL beams.

[00258] Example 31. The apparatus of example 30, wherein: the first plurality of UL beams are mapped substantially evenly across the space of the AoD and the ZoD of the UE; and the first plurality of UL beams are another subset of the plurality of candidate UL beams.

[00259] Example 32. The apparatus of any of examples 25-27, wherein the one or more are processors to: initiate transmission to the UE of an indicator of a number of beams and an indicator of a number of Sounding Reference Signal (SRS) symbols, wherein the UE is to transmit the number of beams in the number of SRS symbols to the UE.

[00260] Example 33. The apparatus of any of examples 25 to 32, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00261] Example 34. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of examples 25 to 33.

[00262] Example 35. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of an Evolved Node B (eNB) to perform an operation comprising: process one or more first Uplink (UL) signals received over a first plurality of UL beams from the UE; select a first UL beam from the first plurality of UL beams; initiate transmission of an identification of the selected first UL beam to the UE, wherein the UE is to select a second plurality of UL beams based on the identification of the first UL beam; process one or more second UL signals received over the second plurality of UL beams from the UE; and select a second UL beam from the second plurality of UL beams.

[00263] Example 36. The machine readable storage media of example 35, wherein the operation comprises: initiate transmission of an identification of the selected second UL beam to the UE, wherein the UE is to transmit UL signals over the second beam.

[00264] Example 37. The machine readable storage media of example 35, wherein the first UL signals comprise Sounding Reference Signal (SRS) symbols transmitted over the first plurality of UL beams.

[00265] Example 38. The machine readable storage media of any of examples 35-37, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the operation comprises: initiate transmission of a Downlink Control Information (DO), the DCI comprising one of: a beam index corresponding to the selected first beam, or an identification of a first Sounding Reference Signal (SRS) symbol of the first UL signals, wherein the first SRS is received over the selected first beam.

[00266] Example 39. The machine readable storage media of any of examples 12-14, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the operation comprises: initiate transmission of a Downlink Control Information (DO), the DCI comprising a prior beam indicator that is to identify the selected first UL beam to the UE.

[00267] Example 40. The machine readable storage media of any of examples 35-37, wherein: a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD, the second plurality of UL being a subset of the plurality of candidate UL beams.

[00268] Example 41. The machine readable storage media of example 40, wherein: the first plurality of UL beams are mapped substantially evenly across the space of the AoD and the ZoD of the UE; and the first plurality of UL beams are another subset of the plurality of candidate UL beams.

[00269] Example 42. The machine readable storage media of any of examples 35-37, wherein the operation comprises: initiate transmission of an indicator of a number of beams and an indicator of a number of Sounding Reference Signal (SRS) symbols to the UE, wherein the UE is to transmit the first number of beams in the second number of SRS symbols to the UE.

[00270] Example 43. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: one or more processors to: process Downlink (DL) signals received from the eNB, determine a number N from the DL signals, generate a Sounding Reference Signal (SRS) symbol for transmission to the eNB, the SRS symbol having a subcarrier spacing of N times Δ£, wherein Αΐ is a subcarrier spacing for one or more data signals transmitted by the UE to the eNB; and an interface to receive the DL signals.

[00271] Example 44. The apparatus of example 42, wherein the one or more are processors to: initiate transmission of the SRS symbol over a plurality of Uplink (UL) beams of the UE. [00272] Example 45. The apparatus of example 43, wherein the one or more are processors to: initiate beam sweeping of N number of Uplink (UL) beams of the UE using the SRS symbol.

[00273] Example 46. The apparatus of any of examples 43-45, wherein the number N is determined from DL signals comprising Downlink Control Information (DCI) signal.

[00274] Example 47. The apparatus of any of examples 43 to 46, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00275] Example 48. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of examples 43 to 47.

[00276] Example 49. An apparatus of a User Equipment (UE) operable to

communicate with an Evolved Node B (eNB) on a wireless network, comprising: one or more processors to: process Downlink (DL) signals received from the eNB, identify a beam sweeping format from the DL signals, and initiate transmission of one or more first Sounding Reference Signal (SRS) symbols over a first plurality of UE beams that are to be received by the eNB over a first eNB beam, in response to a first beam sweeping format being identified.

[00277] Example 50. The apparatus of example 49, wherein the one or more are processors to: initiate transmission of one or more second SRS symbols over a first UE beam that are to be received by the eNB over a first plurality of eNB beams, in response to a second beam sweeping format being identified.

[00278] Example 51. The apparatus of example 50, wherein the one or more are processors to: initiate, in response to a third beam sweeping format being identified, transmission of: one or more third SRS symbols over a second UE beam that are to be received by the eNB over a second plurality of eNB beams, and one or more fourth SRS symbols over a third UE beam that are to be received by the eNB over a third plurality of eNB beams.

[00279] Example 52. The apparatus of any of examples 49-50, wherein the one or more are processors to: identify the beam sweeping format from the DL signals comprising Downlink Control Information (DCI) signal.

[00280] Example 53. The apparatus of any of examples 49 to 50, comprising a transceiver circuitry for generating transmissions and processing transmissions. [00281] Example 54. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of examples 49 to 53.

[00282] Example 55. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: process Downlink (DL) signals received from an Evolved Node B (eNB); identify a beam sweeping format from the DL signals; and initiate transmission of one or more first Sounding Reference Signal (SRS) symbols over a first plurality of UE beams that are to be received by the eNB over a first eNB beam, in response to a first beam sweeping format being identified.

[00283] Example 56. The machine readable storage media of example 55, wherein the operation comprises: initiate transmission of one or more second SRS symbols over a first UE beam that are to be received by the eNB over a first plurality of eNB beams, in response to a second beam sweeping format being identified.

[00284] Example 57. The machine readable storage media of example 56, wherein the operation comprises: initiate, in response to a third beam sweeping format being identified, transmission of: one or more third SRS symbols over a second UE beam that are to be received by the eNB over a second plurality of eNB beams, and one or more fourth SRS symbols over a third UE beam that are to be received by the eNB over a third plurality of eNB beams.

[00285] Example 58. A method to be implemented in an Evolved Node B (eNB), the method comprising: processing one or more first Uplink (UL) signals received over a first plurality of UL beams from the UE; selecting a first UL beam from the first plurality of UL beams; initiating transmission of an identification of the selected first UL beam to the UE, wherein the UE is to select a second plurality of UL beams based on the identification of the first UL beam; processing one or more second UL signals received over the second plurality of UL beams from the UE; and selecting a second UL beam from the second plurality of UL beams.

[00286] Example 59. The method of example 58, further comprising: initiating transmission of an identification of the selected second UL beam to the UE, wherein the UE is to transmit UL signals over the second beam. [00287] Example 60. The method of example 58, wherein the first UL signals comprise Sounding Reference Signal (SRS) symbols transmitted over the first plurality of UL beams.

[00288] Example 61. The method of any of examples 58-60, wherein initiating transmission of the identification of the selected first UL beam to the UE comprises: initiating transmission of a Downlink Control Information (DO), the DCI comprising one of: a beam index corresponding to the selected first beam, or an identification of a first Sounding Reference Signal (SRS) symbol of the first UL signals, wherein the first SRS is received over the selected first beam.

[00289] Example 62. The method of any of examples 58-60, wherein initiating transmission of the identification of the selected first UL beam to the UE comprises: initiating transmission of a Downlink Control Information (DCI), the DCI comprising a prior beam indicator that is to identify the selected first UL beam to the UE.

[00290] Example 63. The method of any of examples 58-60, wherein: a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD, the second plurality of UL being a subset of the plurality of candidate UL beams.

[00291] Example 64. The method of any of examples 58-60, further comprising: initiating transmission of an indicator of a number of beams and an indicator of a number of Sounding Reference Signal (SRS) symbols to the UE, wherein the UE is to transmit the first number of beams in the second number of SRS symbols to the UE.

[00292] Example 65. A method implemented in a User Equipment (UE), the method comprising: processing Downlink (DL) signals received from an Evolved Node B (eNB); identifying a beam sweeping format from the DL signals; and initiating transmission of one or more first Sounding Reference Signal (SRS) symbols over a first plurality of UE beams that are to be received by the eNB over a first eNB beam, in response to a first beam sweeping format being identified.

[00293] Example 66. The method of example 65, further comprising: initiating transmission of one or more second SRS symbols over a first UE beam that are to be received by the eNB over a first plurality of eNB beams, in response to a second beam sweeping format being identified.

[00294] Example 67. The method of example 66, further comprising: initiate, in response to a third beam sweeping format being identified, transmission of: one or more third SRS symbols over a second UE beam that are to be received by the eNB over a second plurality of eNB beams, and one or more fourth SRS symbols over a third UE beam that are to be received by the eNB over a third plurality of eNB beams.

[00295] An abstract is provided that will allow the reader to ascertain the nature and gist of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS We claim:

1. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising:

one or more processors to:

process Downlink (DL) signals received from the eNB, and

determine a precoding matrix for Uplink (UL) transmission, based on processing the DL signals; and

an interface to receive the DL signals.

2. The apparatus of claim 1, wherein to determine the precoding matrix, the one or more processors are to:

process a Downlink Control Information (DCI) received from the eNB, the DCI comprising a Rank Indicator (RI) associated with the precoding matrix; and

determine the precoding matrix, based on the RI.

3. The apparatus of claim 1, wherein the DL signals comprise a Beam Reference Signal (BRS), and wherein to determine the precoding matrix, the one or more processors are to: estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the BRS; and

determine the precoding matrix, based on the estimated eigenvectors.

4. The apparatus of claim 1, wherein to determine the precoding matrix, the one or more processors are to:

process a UL grant from the eNB, the UL grant comprising a Beam Reference Signal (BRS) index identifying a BRS sequence; and

determine the precoding matrix, based on the BRS index.

5. The apparatus of any of claims 1 -4, wherein the one or more are processors to:

generate, for transmission to the eNB, a Beam Reference Signal Receiving Power

(BRS-RP) report, the BRS-RP report identifying a first UL beam that the UE has determined to be appropriate for UL transmission.

6. The apparatus of claim 5, wherein the one or more are processors to: generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the BRS-RP report.

7. The apparatus of claim 1, wherein the DL signals comprise a Channel State

Information Reference Signal (CSI-RS), and wherein to determine the precoding matrix, the one or more processors are to:

estimate eigenvectors associated with a channel between the eNB and the UE, based on processing the CSI-RS; and

determine the precoding matrix, based on the estimated eigenvectors.

8. The apparatus of claim 1, wherein to determine the precoding matrix, the one or more processors are to:

process a UL grant from the eNB, the UL grant comprising a Channel State

Information Reference Signal Resource index (CRI); and

determine the precoding matrix, based on the CRI.

9. The apparatus of claim 8, wherein the CRI is received via Downlink Control Information (DCI) signaling.

10. The apparatus of any of claims 1 and 7-9, wherein the one or more are processors to: generate, for transmission to the eNB, a Channel State Information (CSI) report, the

CSI report identifying a first UL beam that the UE has determined to be appropriate for UL transmission; and

generate, for transmission to the eNB, a Sounding Reference Signal (SRS), the SRS to be transmitted in the first UL beam identified in the CSI report.

11. The apparatus of any of claims 1-10, wherein the one or more are processors to: generate, for transmission to the eNB, a Physical Uplink Shared Channel (PUSCH) signal or a 5G PUSCH (xPUSCH) signal, in accordance with the precoding matrix.

12. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of an Evolved Node-B (eNB) to perform an operation comprising: process one or more first Uplink (UL) signals received over a first plurality of UL beams from the UE;

select a first UL beam from the first plurality of UL beams;

initiate transmission of an identification of the selected first UL beam to the UE, wherein the UE is to select a second plurality of UL beams based on the identification of the first UL beam;

process one or more second UL signals received over the second plurality of UL beams from the UE; and

select a second UL beam from the second plurality of UL beams.

13. The machine readable storage media of claim 12, wherein the operation comprises: initiate transmission of an identification of the selected second UL beam to the UE, wherein the UE is to transmit UL signals over the second beam.

14. The machine readable storage media of claim 12, wherein the first UL signals comprise Sounding Reference Signal (SRS) symbols transmitted over the first plurality of UL beams.

15. The machine readable storage media of any of claims 12-14, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the operation comprises:

initiate transmission of a Downlink Control Information (DCI), the DCI comprising one of:

a beam index corresponding to the selected first beam, or

an identification of a first Sounding Reference Signal (SRS) symbol of the first UL signals, wherein the first SRS is received over the selected first beam.

16. The machine readable storage media of any of claims 12-14, wherein to initiate transmission of the identification of the selected first UL beam to the UE, the operation comprises:

initiate transmission of a Downlink Control Information (DCI), the DCI comprising a prior beam indicator that is to identify the selected first UL beam to the UE.

17. The machine readable storage media of any of claims 12-14, wherein: a plurality of candidate UL beams are mapped in a space of an Azimuth angle of Departure (AoD) and a Zenith angle of Departure (ZoD) of the UE; and

one or more UL beams of the second plurality of UL beams are neighboring to the first beam in the space of the AoD and the ZoD, the second plurality of UL being a subset of the plurality of candidate UL beams.

18. The machine readable storage media of any of claims 12-14, wherein the operation comprises:

initiate transmission of an indicator of a number of beams and an indicator of a number of Sounding Reference Signal (SRS) symbols to the UE,

wherein the UE is to transmit the first number of beams in the second number of SRS symbols to the UE.

19. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising:

one or more processors to:

process Downlink (DL) signals received from the eNB,

determine a number N from the DL signals,

generate a Sounding Reference Signal (SRS) symbol for transmission to the eNB, the SRS symbol having a subcarrier spacing of N times Αΐ, wherein Αΐ is a subcarrier spacing for one or more data signals transmitted by the UE to the eNB; and

an interface to receive the DL signals.

20. The apparatus of claim 19, wherein the one or more are processors to:

initiate transmission of the SRS symbol over a plurality of Uplink (UL) beams of the

UE.

21. The apparatus of claim 19, wherein the one or more are processors to:

initiate beam sweeping of N number of Uplink (UL) beams of the UE using the SRS symbol.

22. The apparatus of any of claims 19-21, wherein the number N is determined from DL signals comprising Downlink Control Information (DCI) signal.

23. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising:

process Downlink (DL) signals received from an Evolved Node B (eNB);

identify a beam sweeping format from the DL signals; and

initiate transmission of one or more first Sounding Reference Signal (SRS) symbols over a first plurality of UE beams that are to be received by the eNB over a first eNB beam, in response to a first beam sweeping format being identified.

24. The machine readable storage media of claim 23, wherein the operation comprises: initiate transmission of one or more second SRS symbols over a first UE beam that are to be received by the eNB over a first plurality of eNB beams, in response to a second beam sweeping format being identified.

25. The machine readable storage media of claim 24, wherein the operation comprises: initiate, in response to a third beam sweeping format being identified, transmission of: one or more third SRS symbols over a second UE beam that are to be received by the eNB over a second plurality of eNB beams, and

one or more fourth SRS symbols over a third UE beam that are to be received by the eNB over a third plurality of eNB beams.