Systems and Methods for Beam Adjustment Requests

Abstract

A device may be configured to: detect a set of beams from a base station. The device may also be configured to: select a beam from the set of beams. The device may also be configured to: determine at least one resource based on the selected beam. The device may also be configured to: send a beam adjustment request to the base station on the at least one determined resource. The request may indicate an index associated with the selected beam. Another device may be configured to: send a first set of beams. The another device may also be configured to: receive a beam adjustment request on at least one resource. The another device may also be configured to: determine a beam index of a beam in the first set of beams based on the request and the at least one resource.

Description

[0001] This application is a divisional application of the patent application with the application date of April 3, 2017, the title of "Systems and Methods for Beam Adjustment Requests", and the application number of 201780023025.5.

[0002] Cross - reference to related applications

[0003] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 322,168, entitled "TRANSMIT REQUEST FOR BEAMTRACKING", filed on April 13, 2016; U.S. Provisional Application Serial No. 62 / 329,180, entitled "TRANSMITREQUEST FOR BEAM TRACKING", filed on April 28, 2016; U.S. Provisional Application No. 62 / 333,120, entitled "TRANSMIT REQUEST FOR BEAM TRACKING", filed on May 6, 2016; U.S. Provisional Application Serial No. 62 / 337,829, entitled "TRANSMIT REQUEST FOR BEAM TRACKING", filed on May 17, 2016; U.S. Provisional Application Serial No. 62 / 338,484, entitled "TRANSMIT REQUEST FOR BEAMTRACKING", filed on May 18, 2016; U.S. Provisional Application Serial No. 62 / 341,051, entitled "TRANSMITREQUEST FOR BEAM TRACKING", filed on May 24, 2016; and U.S. Patent Application No. 15 / 335,353, entitled "SYSTEM AND METHOD FOR BEAM MANAGEMENT", filed on October 26, 2016. The entire disclosures of the above - mentioned applications are hereby incorporated herein by reference. Technical Field

[0004] The present disclosure generally relates to communication systems, and more particularly to user equipment that can notify a base station of a beam adjustment request. Background Art

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ multiple access technologies that are capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the local, national, regional, and even global levels. An exemplary telecommunication standard is Long Term Evolution (LTE). LTE is a collection of enhancements to the Universal Mobile Telecommunication System (UMTS) mobile standard released by the Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband access by using OFDMA on the downlink, SC-FDMA on the uplink, and Multiple-Input Multiple-Output (MIMO) antenna technology to improve spectral efficiency, reduce costs, and enhance services. However, with the continuous growth of the demand for mobile broadband access, there is a need for further improvements to LTE technology. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. SUMMARY

[0007] The following presents a brief summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an exhaustive overview of all expected aspects and is not intended to identify key or critical elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0008] In a millimeter wave (mmW) system, the path loss may be relatively high. Transmissions can be directional to mitigate the path loss. The base station can send one or more beam reference signals by scanning in all directions so that the User Equipment (UE) can identify the optimal "coarse" beam. Additionally, the base station can send a beam refinement request signal so that the UE can track the "fine" beam. If the "coarse" beam identified by the UE changes, the UE may need to notify the base station so that the base station can train one or more new "fine" beams for the UE.

[0009] In various aspects, a UE may send, in a subframe reserved for a random access channel (RACH), an index of an optimal beam and a corresponding beam refinement reference signal session request to a base station. The UE may occupy one or more tones reserved for the RACH. Additionally, the UE may occupy tones reserved for scheduling requests but not for RACH transmissions.

[0010] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be configured to: detect a set of beams from a base station. The apparatus may also be configured to: select a beam from the set of beams. The apparatus may also be configured to: determine at least one resource based on the selected beam. In one aspect, the at least one resource may be at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region. The apparatus may also be configured to: send a beam adjustment request, such as a request for beam tracking, to the base station on the at least one determined resource. In one aspect, the at least one determined resource may indicate an index associated with the selected beam.

[0011] In another aspect of the present disclosure, another method, another computer-readable medium, and another apparatus are provided. The other apparatus may be configured to: send a first set of beams. The other apparatus may also be configured to: receive a beam adjustment request, such as a request for beam tracking, on at least one resource. In one aspect, the at least one resource may be at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region. The other apparatus may also be configured to: determine a beam index of a beam in the first set of beams based on the at least one resource.

[0012] To achieve the foregoing and related purposes, one or more aspects include the features described in detail hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail some illustrative features of one or more aspects. However, these features are merely indicative of some of the various ways in which the principles of the aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0014] Figure 2A 、 2B 、2C, and 2D are diagrams respectively illustrating LTE examples of a DL frame structure, DL channels within the DL frame structure, a UL frame structure, and UL channels within the UL frame structure.

[0015] Figure 3 is a diagram showing an example of a base station and a user equipment (UE) in an access network.

[0016] Figure 4A and 4B is a diagram of a wireless communication system.

[0017] Figures 5A to 5G shows a diagram of a wireless communication system.

[0018] Figure 6 is a diagram of a wireless communication system.

[0019] Figure 7 is a diagram of a wireless communication system.

[0020] Figure 8 is a flowchart of a method of wireless communication.

[0021] Figure 9 is a flowchart of a method of wireless communication.

[0022] Figure 10 is a conceptual data flow diagram showing the data flow between different units / components in an exemplary apparatus.

[0023] Figure 11 is a diagram showing an example of a hardware implementation of an apparatus employing a processing system.

[0024] Figure 12 is a conceptual data flow diagram showing the data flow between different units / components in an exemplary apparatus.

[0025] Figure 13 is a diagram showing an example of a hardware implementation of an apparatus employing a processing system. Detailed Description

[0026] The following detailed description in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein can be implemented. For the purpose of providing a thorough understanding of the various concepts, the detailed description includes specific details. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0027] Aspects of a telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description through various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"), and will be illustrated in the accompanying drawings. These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system.

[0028] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other terms, software should be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, etc.

[0029] Thus, in one or more exemplary embodiments, the described functions can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media can include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures and that can be accessed by a computer.

[0030] Figure 1FIG. is a diagram illustrating an example of a wireless communication system and an access network 100. The wireless communication system (also known as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, and an evolved packet core (EPC) 160. The base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include eNBs. Small cells include femto cells, pico cells, and micro cells.

[0031] The base stations 102 (collectively referred to as the evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN)) interface with the EPC 160 via a backhaul link 132 (e.g., the S1 interface). In addition to other functions, the base station 102 may perform one or more of the following functions: transfer of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC 160) via a backhaul link 134 (e.g., the X2 interface). The backhaul link 134 may be wired or wireless.

[0032] Base station 102 can communicate wirelessly with UE 104. Each base station 102 in base station 102 can provide communication coverage for a corresponding geographical coverage area 110. There can be overlapping geographical coverage areas 110. For example, small cell 102’ can have a coverage area 110’ that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network can also include a Home evolved Node B (eNB) (HeNB), which can provide services to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from base station 102 to UE 104. The communication link 120 can use MIMO antenna technology, including spatial division multiplexing, beamforming, and / or transmit diversity. The communication link can be over one or more carriers. Base station 102 / UE 104 can use up to Y MHz (e.g., 5, 10, 15, 20 MHz) of spectrum allocated in carrier aggregation per carrier to achieve up to a total of Yx MHz (x component carriers) for transmission in each direction. The carriers can be adjacent to each other or can be non-adjacent to each other. The allocation of carriers can be asymmetric with respect to DL and UL (e.g., more or fewer carriers can be allocated for DL compared to UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the Primary Cell (PCell) and the secondary component carriers can be referred to as Secondary Cells (SCells).

[0033] The wireless communication system can also include a Wi-Fi Access Point (AP) 150 that communicates with a Wi-Fi Station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, STA 152 / AP 150 can perform a Clear Channel Assessment (CCA) before communicating to determine if the channel is available.

[0034] Small cell 102’ can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, small cell 102’ can adopt LTE and use the same 5 GHz unlicensed spectrum as that used by Wi-Fi AP 150. Small cell 102’ adopting LTE in the unlicensed spectrum can enhance coverage and / or increase the capacity of the access network. LTE in the unlicensed spectrum can be referred to as Licensed Assisted Access (LAA), Unlicensed LTE (LTE-U), or MuLTEfire.

[0035] A millimeter wave (mmW) base station 180 can operate in mmW frequencies and / or near mmW frequencies to communicate with a UE 182. In one aspect, the UE 182 can be an aspect of the UE 104. Extremely high frequency (EHF) is a part of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and has a wavelength between 1 millimeter and 10 millimeters. The radio waves in this frequency band can be referred to as millimeter waves. Near mmW can extend down to a frequency of 3 GHz, having a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communication using the mmW / near mmW radio frequency band has extremely high path loss and a short range. The mmW base station 180 can utilize beamforming 184 with the UE 182 to compensate for the extremely high path loss and short range.

[0036] The EPC 160 can include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 can communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that processes signaling between the UE 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to an IP service 176. The IP service 176 can include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service (PSS), and / or other IP services. The BM-SC 170 can provide functions for MBMS user service provisioning and delivery. The BM-SC 170 can act as an entry point for content provider MBMS transmissions, can be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and can be used to schedule MBMS transmissions. The MBMS Gateway 168 can be used to distribute MBMS services to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a particular broadcast service, and can be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0037] A base station may also be referred to as a Node B, evolved Node B (eNB), access point, base transceiver station, radio base station, radio transceiver, transceiver functional unit, basic service set (BSS), extended service set (ESS), or some other appropriate term. Base station 102 provides an access point for UE 104 to EPC 160. Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, or any other device with similar functionality. UE 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, radio unit, remote unit, mobile device, radio device, radio communication device, remote device, mobile user station, access terminal, mobile terminal, radio terminal, remote terminal, handheld device, user agent, mobile client, client, or some other appropriate term.

[0038] Referring again to Figure 1 , in some aspects, mmW base station 180 and base station 102 may be integrated into a single base station (although not necessarily). In one aspect, mmW base station 180 may be configured to send a first beam set to UE 104. The first beam set may be considered a "coarse" beam.

[0039] UE 104 may receive the first beam set from mmW base station 180. UE 104 may be configured to select a beam from the beam set. For example, UE 104 may be configured to select the beam with the strongest received power. The selected beam may be associated with an index at mmW base station 180, and UE 104 may be configured to indicate the index to mmW base station 180.

[0040] In one aspect, UE 104 may use at least one resource to indicate the index of the selected beam to mmW base station 180. Thus, UE 104 may be configured to: determine at least one resource based on the selected beam. For example, the at least one resource may include a radio frame index, subframe index, symbol index, or subcarrier index. UE 104 may send a beam adjustment request 198 (e.g., a request for beam tracking, a request to cause mmW base station 180 to start transmitting the indicated beam ID without any further beam tracking, etc.) on the at least one determined resource. The at least one resource may indicate the index associated with the selected beam.

[0041] The mmW base station 180 can receive a request 198 on at least one determined resource. The mmW base station 180 can be configured to determine a beam index of a beam in a first beam set based on at least one resource. For example, the request 198 can include a request to transmit a "fine" beam set based on a selected beam, such that the UE 104 can perform beam refinement.

[0042] Figure 2A FIG. 200 is an example showing the DL frame structure in LTE. Figure 2B FIG. 230 is an example showing channels within the DL frame structure in LTE. Figure 2C FIG. 250 is an example showing the UL frame structure in LTE. Figure 2D FIG. 280 is an example showing channels within the UL frame structure in LTE. Other wireless communication technologies may have different frame structures and / or different channels. In LTE, a frame (10 ms) can be divided into 10 equal-sized subframes. Each subframe can include two consecutive time slots. A resource grid can be used to represent two time slots, and each time slot includes one or more time-concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)). The resource grid is divided into multiple resource elements (REs). In LTE, for a normal cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols in the time domain (for DL, OFDM symbols; for UL, SC-FDMA symbols), for a total of 84 REs. For an extended cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

[0043] As Figure 2A shown, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS can include cell-specific reference signals (CRSs) (sometimes also referred to as common RS), UE-specific reference signals (UE-RSs), and channel state information reference signals (CSI-RSs). Figure 2A Shows the CRSs for antenna ports 0, 1, 2, and 3 (indicated as R0, R1, R2, and R3 respectively), the UE-RS for antenna port 5 (indicated as R5), and the CSI-RS for antenna port 15 (indicated as R). Figure 2B Shows an example of various channels within the DL subframe of a frame. The physical control format indicator channel (PCFIICH) is in symbol 0 of slot 0 and carries an indication of whether the physical downlink control channel (PDCCH) occupies 1, 2, or 3 symbols ( Figure 2Bshows the Control Format Indicator (CFI) of a PDCCH that occupies 3 symbols. The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs), each CCE including nine resource element groups (REGs), each REG including four consecutive resource elements (REs) in one OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH may have 2, 4, or 8 resource block (RB) pairs ( Figure 2B shows two RB pairs, each subset including one RB pair). The Physical Hybrid Automatic Repeat reQuest (ARQ) (HARQ) Indicator Channel (PHICH) is also within symbol 0 of slot 0 and carries a HARQ indicator (HI) that indicates HARQ acknowledgement (ACK) / negative ACK (NACK) feedback based on the Physical Uplink Shared Channel (PUSCH). The Primary Synchronization Channel (PSCH) is within symbol 6 of slot 0 in subframes 0 and 5 of a frame and carries a Primary Synchronization Signal (PSS) that is used by the UE to determine subframe timing and the physical layer identity. The Secondary Synchronization Channel (SSCH) is within symbol 5 of slot 0 in subframes 0 and 5 of a frame and carries a Secondary Synchronization Signal (SSS) that is used by the UE to determine the physical layer cell identity group number. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine the Physical Cell Identifier (PCI). Based on the PCI, the UE may determine the location of the above DL-RS. The Physical Broadcast Channel (PBCH) is within symbols 0, 1, 2, 3 of slot 1 of subframe 0 of a frame and carries the Master Information Block (MIB). The MIB provides the number of RBs in the DL system bandwidth, the PHICH configuration, and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information (such as System Information Blocks (SIBs)) that is not sent via the PBCH, and paging messages.

[0044] As Figure 2C shown, some of the REs carry Demodulation Reference Signals (DM-RS) for channel estimation at the eNB. Additionally, the UE may transmit a Sounding Reference Signal (SRS) in the last symbol of a subframe. The SRS may have a comb structure and the UE may transmit the SRS on one of the teeth of the comb. The SRS may be used by the eNB for channel quality estimation to enable frequency-dependent scheduling on the UL. Figure 2DShows an example of various channels within the UL subframe of a frame. The Physical Random Access Channel (PRACH) can be within one or more subframes in the frame based on the PRACH configuration. The PRACH can include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. The Physical Uplink Control Channel (PUCCH) can be located at the edge of the UL system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and can additionally be used to carry buffer status reports (BSR), power headroom reports (PHR), and / or UCI.

[0045] Figure 3 Is a block diagram of a base station 310 communicating with a UE 350 in an access network. In one aspect, the base station 310 can be an aspect of the mmW base station 180 and / or the base station 102. In the DL, IP packets from the EPC 160 can be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the transfer of higher layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0046] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 maps to a signal constellation based on various modulation schemes such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), and M-quadrature amplitude modulation (M-QAM). The encoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a stream of time domain OFDM symbols. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. The channel estimates may be derived based on reference signals transmitted by the UE 350 and / or channel status feedback. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with the corresponding spatial stream for transmission.

[0047] At the UE 350, each receiver 354RX receives signals via its respective antenna 352. Each receiver 354RX recovers the information modulated on the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 may perform spatial processing of the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on the channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0048] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0049] Similar to the functions described in connection with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with transfer of higher layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0050] The TX processor 368 may use channel estimates derived by the channel estimator 358 based on reference signals or feedback transmitted by the base station 310 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via a separate transmitter 354TX. Each transmitter 354TX may modulate an RF carrier using the corresponding spatial stream for transmission.

[0051] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver functions at the UE 350. Each receiver 318RX receives signals via its respective antenna 320. Each receiver 318RX recovers the information modulated on the RF carrier and provides the information to the RX processor 370.

[0052] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0053] Figure 4A and 4B FIG. is a diagram illustrating an example of the transmission of beamforming signals between a base station (BS) and a UE. The BS may be embodied as a BS in a mmW system (e.g., a mmW BS). Referring to Figure 4A , FIG. 400 illustrates a BS 404 in a mmW system that transmits beamforming signals 406 (e.g., beam reference signals) in different transmission directions (e.g., directions A, B, C, and D). In one example, the BS 404 may scan through the transmission directions according to the order A-B-C-D. In another example, the BS 404 may scan through the transmission directions according to the order B-D-A-C. Although only four transmission directions and two transmission orders are described with respect to Figure 4A , any number of different transmission directions and transmission orders are contemplated.

[0054] After transmitting the signal, the BS 404 may switch to the receive mode. In the receive mode, the BS 404 may scan through different receive directions using an order or pattern that corresponds (maps) to the order or pattern that the BS 404 previously used to transmit synchronization / discovery signals in different transmission directions. For example, if the BS 404 previously transmitted synchronization / discovery signals in transmission directions according to the order A-B-C-D, the BS 404 may scan through the receive directions according to the order A-B-C-D to attempt to receive an associated signal from the UE 402. In another example, if the BS 404 previously transmitted synchronization / discovery signals in transmission directions according to the order B-D-A-C, the BS 404 may scan through the receive directions according to the order B-D-A-C to attempt to receive an associated signal from the UE 402.

[0055] The propagation delay on each beamforming signal allows the UE 402 to perform a receive (RX) scan. The UE 402 in the receive mode may scan through different receive directions to attempt to detect the synchronization / discovery signal 406 (see Figure 4B)。UE 402 can detect one or more synchronization / discovery signals 406 in the synchronization / discovery signal 406. When a strong synchronization / discovery signal 406 is detected, UE 402 can determine the optimal transmission direction of BS 404 corresponding to the strong synchronization / discovery signal and the optimal reception direction of UE 402. For example, UE 402 can determine the preliminary antenna weights / directions of the strong synchronization / discovery signal 406, and can also determine the time and / or resources at which BS 404 is expected to optimally receive the beamforming signal. Thereafter, UE 402 can attempt to associate with BS 404 via the beamforming signal.

[0056] BS 404 can scan through multiple directions using multiple ports in a cell-specific manner in the first symbol of the synchronization subframe. For example, BS 404 can scan through different transmission directions (e.g., directions A, B, C, and D) using four ports in a cell-specific manner in the first symbol of the synchronization subframe. In one aspect, these different transmission directions (e.g., directions A, B, C, and D) can be considered "coarse" beam directions. In one aspect, beam reference signals (BRS) can be transmitted in different transmission directions (e.g., directions A, B, C, and D).

[0057] In one aspect, BS 404 can scan four different transmission directions (e.g., directions A, B, C, and D) using four ports in a cell-specific manner in the second symbol of the synchronization subframe. Synchronization beams can appear in the second symbol of the synchronization subframe.

[0058] Referring to Figure 4B FIG. 420, UE 402 can listen for beamforming discovery signals in different reception directions (e.g., directions E, F, G, and H). In one example, UE 402 can scan through the reception directions according to the order E - F - G - H. In another example, UE 402 can scan through the reception directions according to the order F - H - E - J. Although only four reception directions and two reception orders are described with respect to Figure 4B any number of different reception directions and reception orders are contemplated.

[0059] UE 402 may attempt to associate by sending beamforming signals 426 (e.g., association signals or another indication of an optimal "coarse" beam or optimal "fine" beam) in different transmission directions (e.g., directions E, F, G, and H). In one aspect, UE 402 may send the association signal 426 along the optimal reception direction of UE 402 at a time / resource where BS 404 is expected to optimally receive the association signal. BS 404 in receive mode may scan through different reception directions and detect the association signal 426 from UE 402 during one or more time slots corresponding to the reception directions. When a strong association signal 426 is detected, BS 404 may determine the optimal transmission direction of UE 402 and the optimal reception direction of BS 404 corresponding to the strong association signal. For example, BS 404 may determine the preliminary antenna weights / directions of the strong association signal 426 and may also determine the time and / or resources where UE 402 is expected to optimally receive the beamforming signal. Any of the processes discussed above with respect to Figure 4A and 4B can be refined or repeated such that UE402 and BS 404 ultimately learn the optimal transmission direction and optimal reception direction for establishing a link with each other. Such refinement and repetition may be referred to as beam training.

[0060] In one aspect, BS 404 may select an order or pattern for sending synchronization / discovery signals based on the number of beamforming directions. Subsequently, BS 404 may send a signal for a time period long enough for UE 402 to scan through several beamforming directions to attempt to detect the synchronization / discovery signal. For example, the BS beamforming directions may be indicated by n, where n is an integer from 0 to N and N is the maximum number of transmission directions. Additionally, the UE beamforming directions may be indicated by k, where k is an integer from 0 to K and K is the maximum number of reception directions. When UE 402 detects the synchronization / discovery signal from BS 404, UE 402 may discover that the strongest synchronization / discovery signal is received when the UE 402 beamforming direction is k = 2 and the BS 404 beamforming direction is n = 3. Thus, UE 402 may respond to BS 404 (send a beamforming signal) using the same antenna weights / directions in the corresponding response time slot. That is, UE 402 may use the UE 402 beamforming direction k = 2 to send a signal to BS 404 during the time slot when BS 404 is expected to perform a receive scan at the BS 404 beamforming direction n = 3.

[0061] In a millimeter wave (mmW) system, path loss can be relatively high. Transmission can be directional to mitigate path loss. The BS can send one or more beam reference signals by scanning in all directions so that the user equipment (UE) can identify the optimal "coarse" beam. Additionally, the BS can send a beam refinement request signal so that the UE can track the "fine" beam. If the "coarse" beam identified by the UE changes, the UE may need to notify the BS so that the BS can train one or more new "fine" beams for the UE.

[0062] In various aspects, the UE can send the index of the optimal beam and the corresponding beam refinement reference signal session request to the BS in a subframe reserved for the RACH. The UE can occupy one or more tones reserved for the RACH. Additionally, the UE can occupy tones reserved for scheduling requests but not for RACH transmission.

[0063] Figures 5A to 5G FIG. is an example showing the transmission of beamforming signals between the BS and the UE. The BS 504 can be embodied as a BS in a mmW system (mmW BS). It should be noted that although some beams are shown adjacent to each other, such an arrangement can be different in different aspects (e.g., beams transmitted during the same symbol may not be adjacent to each other).

[0064] In one aspect, the beam set can include eight different beams. For example, Figure 5A FIG. shows eight beams 521, 522, 523, 524, 525, 526, 527, 528 in eight different directions. In one aspect, the BS 504 can be configured to beamform for the transmission of at least one of the beams 521, 522, 523, 524, 525, 526, 527, 528 to the UE 502. In one aspect, the BS 504 can use eight ports to scan / transmit 112 directions during a synchronization subframe.

[0065] In one aspect, the BS can send beam reference signals (BRS) in multiple directions during a synchronization subframe. In one aspect, the transmission can be cell-specific. Referring to Figure 5B, BS 504 can transmit a set of first beams 521, 523, 525, 527 in four directions. For example, BS 504 can transmit BRS in the synchronization subframe of each of the transmission beams 521, 523, 525, 527. In one aspect, these beams 521, 523, 525, 527 transmitted in four directions can be the odd-indexed beams 521, 523, 525, 527 in four of the eight possible directions of the beam set. For example, BS 504 is capable of transmitting beams 521, 523, 525, 527 in directions adjacent to other beams 522, 524, 526, 528 that BS 504 is configured to transmit. In one aspect, this configuration in which BS 504 transmits beams 521, 523, 525, 527 in four directions can be considered a "coarse" beam set.

[0066] In Figure 5C , UE 502 can determine or select the strongest or preferred beam index. For example, UE 502 can determine that the beam 525 carrying BRS is the strongest or preferred. UE 502 can select a beam by measuring the values of the received power or received quality associated with each of the first beam set 521, 523, 525, 527, comparing the corresponding values with each other, and selecting the beam corresponding to the maximum value. The selected beam can correspond to the beam index at BS 504. UE 502 can send an indication 560 of this beam index to BS 504. In one aspect, the indication 560 can include a request to transmit a beam refinement reference signal (BRRS). The BRRS can be specific to the UE. Those skilled in the art will recognize that the BRRS can be referred to by different terms without departing from the present disclosure, such as a beam refinement signal, a beam tracking signal, or another term.

[0067] In various aspects, UE 502 can determine the resources corresponding to the selected beam index. The resources can include one of a radio frame, a subframe, a symbol, or a subcarrier region. Each resource can correspond to, for example, a radio frame index, a subframe index, a symbol index, or a value of a subcarrier region. In one aspect, UE 502 can have a mapping or table (e.g., a lookup table) stored therein or can have access to a mapping or table, where the mapping or table indicates the corresponding resources (e.g., values or indices) to which the beam index corresponds. For example, UE 502 can determine a beam index and then access the lookup table to determine the resource index or region corresponding to the determined beam index.

[0068] In one aspect, a resource may be included in the PUCCH. In one aspect, at least one resource may be included in a subframe associated with a random access channel (RACH). For example, the resource may be included in the bandwidth reserved for RACH transmission. In another example, at least one resource is included in the bandwidth not reserved for RACH transmission. According to another example, the bandwidth is reserved for scheduling request transmission.

[0069] BS 504 may receive an indication 560, which may include a beam adjustment request (e.g., a request for beam tracking, a request for BRRS, a request for the BS to start transmitting on the indicated beam ID without any further beam tracking, etc.). Based on the indication 560, BS 504 may determine an index corresponding to the selected beam 525. That is, the indication 560 may be carried on a resource determined to correspond to the index of the selected beam 525. In one aspect, BS 504 may have a mapping or table (e.g., a lookup table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resource (e.g., value or index) to which a beam index corresponds. For example, BS504 may determine the resource on which the indication 560 is received and then access the lookup table to determine the beam index (e.g., the index corresponding to the selected beam 525) or region corresponding to the determined beam index.

[0070] In Figure 5D this case, BS 504 may transmit a second beam set based on the index included in the indication 560. For example, UE502 may indicate that the first beam 525 is the strongest or preferred, and in response, BS 504 may transmit a second beam set 524, 525, 526 to UE 502 based on the indicated beam index. In one aspect, compared to those other beams 521, 523, 527 in the first beam set, the beams 524, 525, 526 transmitted based on the indicated beam index may be closer (e.g., spatially and / or in direction) to the selected beam 525. In one aspect, the beams 524, 525, 526 transmitted based on the indicated beam index may be considered a "fine" beam set. In one aspect, BRRS may be transmitted in each of the beams 524, 525, 526 in the fine beam set. In one aspect, the beams 524, 525, 526 in the fine beam set may be adjacent.

[0071] Based on one or more BRRS received in beams 524, 525, 526 in the fine beam set, UE 502 may send a second indication 565 to BS 504 to indicate the optimal "fine" beam. In one aspect, the second indication 565 may use two (2) bits to indicate the selected beam. For example, UE 502 may send an indication 565 that indicates an index corresponding to the selected beam 525. Subsequently, BS 504 may use the selected beam 525 to transmit to UE 502.

[0072] Referring Figure 5E , BS 504 may send BRS in multiple directions during a synchronization subframe. In one aspect, BS504 may continue to send BRS even, for example, after UE 502 has transmitted an indication 565 of the selected beam 525. For example, BS 504 may send beams 521, 523, 525, 527 (e.g., the "coarse" beam set) each including BRS.

[0073] Referring Figure 5F , the quality of the selected beam 525 may deteriorate such that UE 502 may no longer be willing to use the selected beam 525 for communication. Based on the BRS (e.g., continuously sent) sent in the synchronization subframe, UE 502 may determine a new beam 523 on which to communicate. For example, UE 502 may determine that the beam 523 carrying the BRS is the strongest or preferred. UE 502 may select a beam based on measuring values of received power or received quality associated with each beam in the beam set 521, 523, 525, 527, comparing the corresponding values with each other, and selecting the beam corresponding to the maximum value. The selected beam may correspond to a beam index at BS 504. UE 502 may send a request 570 to BS 504 to indicate the beam index. In one aspect, the indication 560 may include a request to transmit a beam refinement reference signal (BRRS). The BRRS may be specific to the UE.

[0074] In various aspects, UE 502 may determine a resource corresponding to the selected beam index. The resource may include one of a radio frame, a subframe, a symbol, or a subcarrier region. Each resource may correspond to a value such as a radio frame index, a subframe index, a symbol index, or a subcarrier region value. In one aspect, a beam adjustment request (BAR) may be used to request BS504 to send BRRS.

[0075] In one aspect, the UE 502 may have a mapping or table (e.g., a look-up table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resources (e.g., values or indices) to which the beam indices correspond. For example, the UE 502 may determine a beam index and then access the look-up table to determine the resource index or region corresponding to the determined beam index.

[0076] In one aspect, at least one resource may be included in the physical uplink control channel (PUCCH). However, the BS 504 is only able to detect signals from the UE 502 in the first indicated beam 525 ( Figure 5C ). Thus, the UE 502 may require a link budget on the PUCCH in order to use the PUCCH to indicate the request 570.

[0077] In another aspect, at least one resource may be included in a subframe associated with the RACH. In one aspect, at least one resource is included in the bandwidth reserved for RACH transmission. In one aspect, at least one resource may be included in the bandwidth not reserved for RACH transmission. In one aspect, at least one resource may be included in the bandwidth reserved for scheduling request (SR) transmission, where at least one resource may be in the RACH subframe but may not be reserved for RACH transmission.

[0078] Regarding Figure 5G , the BS 504 may receive the request 570 from the UE 502. The BS 504 may be configured to determine a beam index of a beam set (e.g., the beam set shown in Figure 5E ) based on at least one of the request and / or at least one resource. For example, the request 750 may be carried on a resource determined to correspond to the index of the selected beam 523. In one aspect, the BS 504 may have a mapping or table (e.g., a look-up table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resources (e.g., values or indices) to which the beam indices correspond. For example, the BS 504 may determine the resource on which the request 570 is received and then access the look-up table to determine the beam index (e.g., the index corresponding to the selected beam 523) or region corresponding to the determined beam index. In one aspect, the uplink reception beam during the reception of the request 570 may be based on the set of the first beams 521, 523, 525, 527.

[0079] In one aspect, BS 504 may be configured to: send a set of second beams 522, 523, 524 based on at least one of the request 570 and / or at least one resource carrying the request 570. In one aspect, BS 504 may be configured to: determine a range of indices based on the request 570 and / or at least one resource carrying the request 570. In one aspect, BS 504 may determine a beam index based on at least one subcarrier of at least one resource carrying the request 570.

[0080] In one aspect, BS 504 may determine a beam index from the range based on the strength of signals in different receive chains through which BS 504 receives the request 570. For example, BS 504 may receive the request 570 through multiple receive chains of BS 504. BS 504 may determine the signal strength of the request 570 for each receive chain through which it receives the request 570. BS 504 may determine that each receive chain is associated with at least one beam index (e.g., the beam index of beam 523), and thus, BS 504 may determine the beam index corresponding to the receive chain in which the highest signal strength of the request 570 is detected.

[0081] In one aspect, BS 504 may send an instruction for performing beam refinement to UE 502 based on the request 570. In one aspect, the instruction for performing beam refinement may be based on the selected beam 523 indicated by UE 502 to BS 504. In one aspect, BS 504 may send one or more BRRSs in one or more synchronization subframes of the set of second beams 522, 523, 524. UE 502 may measure the BRRSs in the scheduled subframes to determine the optimal beam of BS 504, such as by measuring the respective values of the received power and / or received quality of each beam in the set of second beams 522, 523, 524, and by comparing the measured values with each other to determine the highest value corresponding to the beams in the set of second beams 522, 523, 524.

[0082] Refer to Figure 6, which shows a block diagram for indicating a selected beam. In some aspects, BS 504 may transmit a set of beams A-H 521, 523, 525, 527, 529, 531, 533, 535. In some aspects, for example, when the first selected beam deteriorates, UE 502 may need to indicate a newly selected beam among beams A-H 521, 523, 525, 527, 529, 531, 533, 535 to BS 504. However, since BS 504 can only detect transmissions from UE 502 in the direction of the first selected beam, UE 502 can use RACH subframe 600 to identify a new beam (e.g., because beamforming may not be required for RACH in the cell).

[0083] In one aspect, at least one of BS 504 and / or UE 502 maintains a mapping between beams (e.g., beams A-H 521, 523, 525, 527, 529, 531, 533, 535) associated with a synchronization (or BRS) session and a RACH session. That is, UE 502 may be configured to: use one or more resources of RACH subframe 600 to indicate a beam index, such as by sending a request (e.g., request 570) on at least one resource corresponding to the beam index selected by UE 502.

[0084] For example, UE 502 may be configured to: if the selected beam index (e.g., beam 523) corresponds to one of the beams A-D 521, 523, 525, 527, then send request 570 as a RACH sequence in symbols 0 and 1 of RACH subframe 600. Similarly, UE 502 may be configured to: if the selected beam index corresponds to one of the beams E-H 529, 531, 533, 535, then send request 570 as a RACH sequence in symbols 2 and 3 of RACH subframe 600.

[0085] In one aspect, the UE 502 can use at least one subcarrier to indicate a specific beam within a range. For example, the UE 502 can indicate a beam within the range of beams A-D 521, 523, 525, 527 by using at least one pair of subcarriers among subcarrier pairs 620, 622, 624, 626. Similarly, the UE 502 can indicate a beam within the range of beams E-H 529, 531, 533, 535 by using at least one pair of subcarriers among subcarrier pairs 620, 622, 624, 626. For example, subcarrier 620 can indicate the first beam of the range, and thus, when the UE 502 transmits a RACH sequence on symbols 0 and 1 and subcarrier 620, the UE 502 is indicating the selected beam A 521. As another example, the UE 502 can indicate the selected beam G 533 by transmitting a RACH sequence on subcarrier 624 (corresponding to the third beam within the range) on symbols 2 and 3. Thus, the BS 504 can determine the selected beam index based on at least one resource on which the RACH sequence is transmitted.

[0086] In another aspect, the BS 504 determines a beam index from within a range based on the strength of the signal in different receive chains through which the BS 504 receives the request 570. For example, the BS 504 can receive the request 570 through multiple receive chains of the BS 504. The BS 504 can determine the signal strength of the request 570 for each receive chain through which it receives the request 570. The BS 504 can determine that each receive chain is associated with at least one beam index (e.g., the beam index of beam 523), and thus, the BS 504 can determine the beam index corresponding to the receive chain in which the highest signal strength of the request 570 is detected. For example, the UE 502 can select beam E 529 as the newly selected beam. To indicate the selected beam E 529, the UE 502 can transmit a RACH sequence on symbols 2 and 3 of a RACH subframe. The BS 504 can receive the RACH sequence through one or more receive chains of the BS 504. The BS 504 can determine the signal strength of the RACH sequence for each receive chain of the BS 504. The BS 504 can determine the selected beam E 529 because the highest signal strength of the RACH sequence can occur at the receive chain corresponding to the third beam of the range (and the range can be indicated by symbols 2 and 3).

[0087] Using a RACH subframe to indicate a selected beam index may be subject to various limitations. For example, when transmitting a RACH sequence, UE 502 may not be time-aligned with BS 504. The cyclic prefix in the RACH sequence may be larger than the sum of the round-trip time and the delay spread (e.g., in a conventional transmission, the cyclic prefix may need to be larger than the delay spread). Therefore, the available number of cyclic offsets for the UE may be low. For example, the available number of cyclic offsets may be less than or equal to the sequence duration and / or the cyclic prefix duration. Therefore, the number of degrees of freedom in the RACH reservation area of RACH subframe 600 may be low. In addition, if many UEs send beam adjustment requests in RACH subframe 600, there may be conflicts. In addition, the RACH framework may include additional overhead (e.g., BS 504 sends a RACH response and allocates a separate grant to the UE to send additional information).

[0088] Therefore, UE 502 may send a beam adjustment request (e.g., a request for BRRS) in the unoccupied bandwidth of the RACH subframe. This area may not be reserved for RACH transmission. In one aspect, this area may be reserved for scheduling request (SR) transmission.

[0089] Referring to Figure 7 , a block diagram for indicating a selected beam is shown. In some aspects, BS 504 may send a set of beams A-H 521, 523, 525, 527, 529, 531, 533, 535. In some aspects, for example, when the first selected beam deteriorates, UE 502 may need to indicate a newly selected beam among beams A-H 521, 523, 525, 527, 529, 531, 533, 535 to BS 504. However, since BS 504 can only detect transmissions from UE 502 in the direction of the first selected beam, UE 502 may use RACH subframe 700 to identify the new beam.

[0090] In some aspects, UE 502 may use an area 710 that may not be reserved for RACH transmission. In one aspect, this area 710 may be reserved for SR transmission (e.g., area 710 may be used to collect buffer status reports). In one aspect, a BAR process may be configured in UE 502. For example, if a dedicated SR for a BRRS request is configured for UE502, the PHY layer of UE 502 may signal a dedicated RS for the BRRS request in the SR area 710 of RACH subframe 700.

[0091] In one aspect, UE 502 may transmit in region 710 only when UE 502 is time-aligned with BS 504. The number of available cyclic offsets associated with region 710 may be higher than those available cyclic offsets in region 712 that are reserved for RACH transmissions. Therefore, there may be a higher degree of freedom associated with region 710 compared to region 712. For example, multiple UEs can send requests (e.g., requests for beam tracking and / or BRRS) through region 710 (e.g., more UEs can send requests through RACH transmission region 712).

[0092] In one aspect, UE 502 may select a transmission time for SR based on the symbol index of the strongest beam (e.g., the beam in which the strongest BRS is received during a synchronization subframe). In one aspect, if directed by a higher layer, UE 502 may transmit SR during RACH subframe 700. For example, multiple parameters may be provided to the PHY layer of UE 502, including the frequency band number N SR 、cyclic offset v, root u, parameter f′, system frame number (SFN), BRS transmission period N BRS 、the number of symbols during RACH subframe 700 N RACH (BS 504 may apply different beams (e.g., different receive beams) for RACH subframe 700), the number of RACH subframes in each radio frame M, the index m of the current RACH subframe, the symbol with the strongest synchronization beam Root u may be cell-specific. UE 502 may calculate the symbol index l based on SFN, N BRS 、N RACH 、M, m and to calculate the symbol index l.

[0093] For example,

[0094]

[0095] where N rep may indicate the number of symbols dedicated to a single RACH transmission (e.g., N rep = 2).

[0096] In one aspect, at least one of BS 504 and / or UE 502 maintains a mapping between the beams associated with the synchronization (or BRS) session and region 710 (e.g., beams A-H 521, 523, 525, 527, 529, 531, 533, 535). That is, UE 502 can be configured to use one or more resources of RACH subframe 700 to indicate a beam index, such as by sending a request (e.g., request 570) on at least one resource corresponding to the beam index selected by UE 502.

[0097] For example, UE 502 can be configured to: if the selected beam index (e.g., beam 523) corresponds to one of beams A-D 521, 523, 525, 527, send request 570 in symbols 0 and 1 of RACH subframe 700. Similarly, UE 502 can be configured to: if the selected beam index corresponds to one of beams E-H 529, 531, 533, 535, send request 570 in symbols 2 and 3 of RACH subframe 700.

[0098] In one aspect, UE 502 can use at least one subcarrier to indicate a specific beam within a range. For example, UE 502 can indicate a beam within the range of beams A-D 521, 523, 525, 527 by using at least one pair of subcarriers 720, 722, 724, 726. Similarly, UE 502 can indicate a beam within the range of beams E-H 529, 531, 533, 535 by using at least one pair of subcarriers 720, 722, 724, 726. For example, subcarrier 720 can indicate the first beam in the range, and thus, when UE 502 sends a request on symbols 0 and 1 and subcarrier 720, UE 502 is indicating the selected beam A 521. As another example, UE 502 can indicate the selected beam G 533 by sending a request on subcarrier 724 (corresponding to the third beam in the range) on symbols 2 and 3. Thus, the base station 702 can determine the selected beam index based on at least one resource on which the request is sent.

[0099] In another aspect, the BS 504 determines a beam index from a range based on the strength of signals in different receive chains through which the BS 504 receives the request 570. For example, the BS 504 can receive the request 570 through multiple receive chains of the BS 504. The BS 504 can determine the signal strength of the request 570 for each receive chain through which it receives the request 570. The BS504 can determine that each receive chain is associated with at least one beam index (e.g., the beam index of beam 523), and thus, the BS 504 can determine the beam index corresponding to the receive chain in which the highest signal strength of the request 570 is detected. For example, the UE 502 can select beam E 529 as the newly selected beam. To indicate the selected beam E 529, the UE 502 can send a request on symbols 2 and 3 of the RACH subframe. The BS 504 can request through one or more receive chains of the BS 504. The BS 504 can determine the signal strength of the request for each receive chain of the BS 504. The BS 504 can determine the selected beam E 529 because the highest signal strength of the request can occur at the receive chain corresponding to the third beam of the range (and the range can be indicated by symbols 2 and 3).

[0100] Figure 8 is a flowchart 800 of a method of wireless communication. The method can be performed by a UE (e.g., UE 502). Those skilled in the art will understand that one or more operations can be omitted, swapped, and / or performed simultaneously.

[0101] At operation 802, the UE can detect a set of beams from the BS, such as by detecting BRSs transmitted in the synchronization subframes of each beam in a first set of beams. In Figure 5E the context, the UE 502 can detect a first set of beams 521, 523, 525, 527, such as by detecting BRSs transmitted in the synchronization subframes of each beam 521, 523, 525, 527. The first set of beams can be odd-indexed beams.

[0102] At operation 804, the UE can select a beam from the set of beams. For example, the UE can determine that the beam carrying the BRS is the strongest or preferred. The UE can select a beam based on measuring values of received power or received quality associated with each beam in the first set of beams, comparing the corresponding values with each other, and selecting the beam corresponding to the maximum value. The selected beam can correspond to a beam index at the BS. In Figure 5F the context, the UE 502 can select beam 523.

[0103] At operation 806, the UE can determine at least one resource based on the selected beam. InFigure 5F In the context of, UE 502 may determine at least one resource based on the selected beam 523. In Figure 6 In the context of, UE 502 may determine symbols 0 and 1 and / or subcarrier 622. In Figure 7 In the context of, UE 502 may determine symbols 0 and 1 and / or subcarriers 722 of region 710.

[0104] In one aspect, the at least one resource indicates at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region. In one aspect, the at least one resource is included in a PUCCH. In one aspect, the at least one resource is included in a subframe associated with a RACH. In one aspect, the at least one resource is included in a bandwidth associated with a RACH. In one aspect, the at least one resource is included in a bandwidth not reserved for RACH transmission (such as a bandwidth reserved for SR transmission). In one aspect, the UE may have a mapping or table (e.g., a look-up table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resource (e.g., a value or an index) corresponding to a beam index. For example, the UE may determine a beam index and then access the look-up table to determine the resource index or region corresponding to the determined beam index.

[0105] At operation 808, the UE may send a beam adjustment request (e.g., a request for BRRS) to the BS on at least one determined resource. The request may indicate an index associated with the selected beam. In Figure 5F In the context of, UE502 may send request 570.

[0106] At operation 810, the UE may receive an instruction (e.g., BRRS) for performing beam refinement based on the request. In Figure 5G In the context of, UE 502 may receive an instruction for performing beam refinement from BS 504 based on request 570.

[0107] At operation 812, the UE may perform beam refinement based on the instruction. The UE may perform beam refinement based on the selected beam. In Figure 5G In the context of, UE 502 may perform beam refinement based on an instruction from BS 504.

[0108] In one aspect, operation 812 may include operations 814 and 816. At operation 814, the UE may receive the selected beam from the BS. In one aspect, the selected beam is included in a first beam set from the BS. In Figure 5G In the context of, UE 502 may receive beam sets 522, 523, 524.

[0109] At operation 816, the UE may determine an optimal receiver beam of the UE corresponding to the selected beam received from the BS. In Figure 5G the context of, the UE 502 may receive the optimal receiver beam of the UE 502 for the beams within the set of beams 522, 523, 524. For example, the UE 502 may determine the optimal receiver beam for beam 523.

[0110] Figure 9 FIG. 900 is a flow chart of a method of wireless communication. The method may be performed by a BS (e.g., BS 504). Those skilled in the art will understand that one or more operations may be omitted, reordered, and / or performed concurrently.

[0111] At operation 902, the BS may transmit a first set of beams, such as by transmitting BRSs in the synchronization subframes of each beam in the first set of beams. The first set of beams may be beams with odd indices. In Figure 5E the context of, the BS 504 may transmit the first set of beams 521, 523, 525, 527.

[0112] At operation 904, the BS may receive a beam adjustment request on at least one resource. In Figure 5F the context of, the BS 504 may receive a request 570 from the UE 502.

[0113] At operation 906, the BS may determine a beam index of a beam in the first set of beams based on the request and / or at least one resource carrying the request. In one aspect, the BS may have a mapping or table (e.g., a look-up table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resource (e.g., value or index) to which the beam index corresponds. For example, the BS may determine the resource on which the request is received and then access the look-up table to determine the beam index (e.g., the index corresponding to the selected beam) or region corresponding to the determined beam index.

[0114] In Figure 5F the context of, for example, when the UE 502 indicates the selected beam 523, the BS 504 may determine at least one resource based on the request 570 and at least one resource carrying the request 570. In Figure 6 the context of, the BS 504 may detect the request 570 on symbols 0 and 1 and / or subcarrier 622 (which may indicate the selected beam 523). In Figure 7 the context of, the BS 504 may detect the request 570 on symbols 0 and 1 and / or subcarrier 722 of region 710 (which may indicate the selected beam 523).

[0115] In one aspect, at least one resource is included in the PUCCH. In one aspect, at least one resource is included in a subframe associated with the RACH. In one aspect, at least one resource is included in the bandwidth associated with the RACH. In one aspect, at least one resource is included in a bandwidth that is not reserved for RACH transmissions (such as a bandwidth reserved for SR transmissions).

[0116] In one aspect, operation 906 may include operations 920 and 922. At operation 920, the BS may determine a range of indices based on at least one resource. In Figure 5F the context of, BS 504 may determine a range of indices based on at least one resource carrying request 570. In Figure 6 the context of, BS 504 may determine symbols 0 and 1 to indicate a range of beam indices. In Figure 7 the context of, BS 504 may determine symbols 0 and 1 to indicate a range of beam indices.

[0117] At operation 922, the BS may determine a beam index based on at least one subcarrier carrying the request or the receive chain through which the BS receives the request. In Figure 6 the context of, BS 504 may determine subcarrier 622 to indicate a beam index within the range of beam indices. In Figure 7 the context of, BS 504 may determine subcarrier 722 to indicate a beam index within the range of beam indices. Alternatively, BS 504 may determine the beam index based on the receive chain through which BS 504 receives the request.

[0118] At operation 908, the BS may transmit a second beam set based on the beam index. The second beam set may be a "fine" beam. In Figure 5G the context of, BS 504 may transmit a second beam set 522, 523, 524. In one aspect, BS 504 may receive another beam index, such as two (2) bits from UE 502, based on the second beam set.

[0119] Figure 10 FIG. 1000 is a conceptual data flow diagram showing the data flow between different units / components in an exemplary apparatus 1002. The apparatus may be a UE. The apparatus 1002 may include a receiving component 1004, which may be configured to receive signals from an mmW BS (e.g., BS 1050). The apparatus 1002 may include a transmitting component 1010, which is configured to transmit signals to an mmW BS (e.g., BS1050).

[0120] Device 1002 may include a beam detection component 1012 configured to detect one or more beams transmitted by mmW BS 1050. In one aspect, the beam detection component 1012 may be configured to detect one or more BRSs transmitted by mmW BS 1050 over a "coarse" beam set. The beam detection component 1012 may monitor one or more synchronization subframes and detect one or more BRSs transmitted by mmW BS 504.

[0121] A beam selection component 1014 may be configured to select a beam based on the BRSs detected by the beam detection component 1012. For example, the beam selection component 1014 may be configured to measure the received power or received quality of one or more BRSs and select the beam corresponding to the highest received power or received quality. The beam selection component 1014 may provide an indication of the selected beam to a resource determination component 1016.

[0122] The selected beam may correspond to an index. The resource determination component 1016 may be configured to determine a resource to carry a beam adjustment request (e.g., a request for BRRSs) to indicate the selected beam. For example, the resource may include one of a radio frame, a subframe, a symbol, or a subcarrier region. Each resource may correspond to a value such as a radio frame index, a subframe index, a symbol index, or a subcarrier region value. In one aspect, the resource determination component 1016 may have a mapping or table (e.g., a look-up table) stored therein or may have access to a mapping or table, where the mapping or table indicates the corresponding resources (e.g., values or indices) to which beam indices correspond. For example, the resource determination component 1016 may determine a beam index and then access the look-up table to determine the resource index or region corresponding to the determined beam index.

[0123] In one aspect, the resource is included in a subframe associated with RACH. In one aspect, the resource is included in a bandwidth reserved for RACH transmission. In one aspect, the resource is included in a bandwidth not reserved for RACH transmission. In one aspect, the bandwidth is reserved for scheduling request transmission. In one aspect, the resource is included in PUCCH.

[0124] The resource determination component 1016 may provide an indication of the determined resource to a transmission component 1010. The transmission component 1010 may be configured to transmit a beam adjustment request to mmW BS 1050 over the determined resource to indicate the index associated with the selected beam. The beam adjustment request may include a request for BRRSs.

[0125] In one aspect, beam detection component 1012 can receive instructions from mmW BS 1050 to perform beam refinement at a receiver (e.g., receiving component 1004) of apparatus 1002. Beam detection component 1012 can perform beam refinement based on the request.

[0126] The device may include performing the above Figure 8 Each block in the flowchart of the algorithm is an additional component. As such, the above can be performed by the component Figure 8 Each block in the flowchart of the process / algorithm may be included in the apparatus, and the apparatus may include one or more of those components. The component may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0127] Figure 11 1 is a diagram 1100 showing an example of a hardware implementation of an apparatus 1002' employing a processing system 1114. The processing system 1114 may be implemented using a bus architecture, generally represented by a bus 1124. The bus 1124 may include any number of interconnected buses and bridges, depending on the specific application and overall design constraints of the processing system 1114. The bus 1124 links together various circuits including one or more processors and / or hardware components (represented by the processor 1104), components 1004, 1010, 1012, 1014, 1016, and computer readable media / memory 1106. The bus 1124 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are circuits well known in the art and will not be described further.

[0128] Processing system 1114 may be coupled to transceiver 1110. Transceiver 1110 is coupled to one or more antennas 1120. Transceiver 1110 provides means for communicating with various other devices via a transmission medium. Transceiver 1110 receives signals from one or more antennas 1120, extracts information from the received signals, and provides the extracted information to processing system 1114 (specifically, receiving component 1004). Additionally, transceiver 1110 receives information from processing system 1114 (specifically, transmitting component 1010) and generates signals to be applied to one or more antennas 1120 based on the received information. Processing system 1114 includes a processor 1104 coupled to a computer-readable medium / memory 1106. Processor 1104 is responsible for general processing, including the execution of software stored on computer-readable medium / memory 1106. When processor 1104 executes the software, the software causes processing system 1114 to perform the various functions described above for any particular device. Computer-readable medium / memory 1106 may also be used to store data manipulated by processor 1104 when executing the software. Processing system 1114 further includes at least one of components 1004, 1010, 1012, 1014, 1016. The components may be software components running in processor 1104, resident / stored in computer-readable medium / memory 1106, one or more hardware components coupled to processor 1104, or some combination thereof. Processing system 1114 may be a component of UE 350 and may include at least one of TX processor 368, RX processor 356, and controller / processor 359 and / or memory 360.

[0129] In one configuration, a device 1002 / 1002' for wireless communication includes: means for detecting a set of beams from a base station. Device 1002 / 1002' may further include: means for selecting a beam from the set of beams. Device 1002 / 1002' may further include: means for determining at least one resource based on the selected beam. In one aspect, the at least one resource may be at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region. Device 1002 / 1002' may further include: means for transmitting a beam adjustment request to the base station on at least one determined resource, wherein the at least one determined resource indicates an index associated with the selected beam.

[0130] In one aspect, the beam adjustment request to the base station includes a request for BRRS. In one aspect, at least one resource is included in a subframe associated with RACH. In one aspect, at least one resource is included in the bandwidth reserved for RACH transmission. In one aspect, at least one resource is included in the bandwidth not reserved for RACH transmission. In one aspect, the bandwidth is reserved for scheduling request transmission. In one aspect, at least one resource is included in PUCCH.

[0131] In one aspect, apparatus 1002 / 1002' may further include: a unit for receiving, from a base station, instructions for performing beam refinement at a receiver of the UE based on a request. Apparatus 1002 / 1002' may further include: apparatus 1002 / 1002' performs beam refinement based on the request. In one aspect, beam refinement at the UE receiver is based on the selected beam.

[0132] The above unit may be one or more of the above components of apparatus 1002 and / or the processing system 1114 of apparatus 1002' configured to perform the functions recited by the above unit. As described above, the processing system 1114 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Accordingly, in one configuration, the above unit may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the above unit.

[0133] Figure 12 FIG. 1200 is a conceptual data flow diagram showing the data flow between different units / components in an exemplary apparatus 1202. The apparatus may be a base station (e.g., a mmW base station). Apparatus 1202 includes a receiving component 1204, which may receive signals from a UE (e.g., UE 1250). Apparatus 1202 may include a transmitting component 1210, which may transmit signals to a UE (e.g., UE 1250).

[0134] In one aspect, the beam transmitting component 1216 may be configured to: transmit a first beam to UE 1250. For example, the beam transmitting component 1216 may be configured to: transmit a corresponding BRS in a corresponding synchronization subframe of the corresponding beam. The first beam set may be a "coarse" beam set.

[0135] UE 1250 may receive the first beam set and select an optimal or preferred beam. Subsequently, UE 1250 may send a beam adjustment request (e.g., a BRRS request). The receiving component 1204 may receive the request (which is carried on at least one resource), and provide it to the index determination component 1212.

[0136] The index determination component 1212 can be configured to determine the beam index of the beams in the first beam set based on at least one resource carrying the request. The index determination component 1212 can be configured to determine the resource carrying the beam adjustment request in order to determine the beam selected by the UE 1250. For example, the resource can include one of a radio frame, a subframe, a symbol, or a subcarrier region. Each resource can correspond to a value such as a radio frame index, a subframe index, a symbol index, or a subcarrier region value. In one aspect, the index determination component 1212 can have a mapping or table (e.g., a look-up table) stored therein or can have access to a mapping or table, where the mapping or table indicates the corresponding resource (e.g., value or index) to which the beam index corresponds. For example, the index determination component 1212 can determine the beam index and then access the look-up table to determine the resource index or region corresponding to the beam index.

[0137] In one aspect, the resource is included in a subframe associated with the RACH. In one aspect, the resource is included in the bandwidth reserved for RACH transmission. In one aspect, the resource is included in the bandwidth not reserved for RACH transmission. In one aspect, the bandwidth is reserved for scheduling request transmission. In one aspect, the resource is included in the PUCCH.

[0138] In one aspect, the index determination component 1212 determines the beam index from a range based on the strength of the signal in different receive chains (e.g., the receive chains included in the receive chains of the receiving component 1204) through which the device 1204 receives the request. For example, the receiving component 1204 can receive the request through multiple receive chains. The index determination component 1212 can determine the signal strength of the request for each receive chain through which the request is received. The index determination component 1212 can determine that each receive chain is associated with at least one beam index, and thus, the index determination component 1212 can determine the beam index corresponding to the receive chain in which the highest signal strength of the request is detected.

[0139] The index determination component 1212 can provide an indication of the beam index selected by the UE 1250 to the beam refinement component 1214. The beam refinement component 1214 can determine a second beam set to be sent to the UE 1250. The second beam set can be a "fine" beam set, which can be closer in direction and / or in space to the beam selected by the UE 1250, and the index of the beam selected by the UE 1250 can be determined by the index determination component 1212. The beam refinement component 1214 can provide an indication of the index of the second beam set to the beam transmission component 1216.

[0140] The beam transmitting component 1216 may be configured to transmit a second beam to the UE 1250. For example, the beam transmitting component 1216 may be configured to: transmit a corresponding BRRS in a corresponding synchronization subframe of a corresponding beam. The second beam set may be a "fine" beam set.

[0141] In one aspect, the beam transmitting component 1216 may transmit an instruction for performing beam refinement to the UE 1250 based on a request. In one aspect, the instruction for performing beam refinement may be based on the selected beam determined by the beam determination component 1212. The beam transmitting component 1216 may perform beam tracking with the UE 1250.

[0142] The apparatus may include additional components that perform each of the blocks in the algorithm of the flowchart described above Figure 9 and thus each block in the flowchart described above may be performed by a component, and the apparatus may include one or more of those components. The components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof. Figure 9 FIG. 1300 is a diagram illustrating an example of a hardware implementation of an apparatus 1202' employing a processing system 1314. The processing system 1314 may be implemented using a bus architecture (generally represented by bus 1324). The bus 1324 may include any number of interconnected buses and bridges, depending on the specific application and overall design constraints of the processing system 1314. The bus 1324 links together various circuits of one or more processors and / or hardware components (represented by processor 1304), components 1204, 1210, 1212, 1214, 1216, and computer-readable medium / memory 1306. The bus 1324 may also link together various other circuits, such as a timing source, peripherals, voltage regulators, and power management circuits, which are well-known circuits in the art and thus will not be described further.

[0143] Figure 13

[0144] ​The processing system 1314 can be coupled to the transceiver 1310. The transceiver 1310 is coupled to one or more antennas 1320. The transceiver 1310 provides a unit for communicating with various other devices via a transmission medium. The transceiver 1310 receives signals from one or more antennas 1320, extracts information from the received signals, and provides the extracted information to the processing system 1314 (specifically, the receiving component 1204). Additionally, the transceiver 1310 receives information from the processing system 1314 (specifically, the transmitting component 1210) and generates signals to be applied to one or more antennas 1320 based on the received information. The processing system 1314 includes a processor 1304 coupled to a computer-readable medium / memory 1306. The processor 1304 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory 1306. When the processor 1304 executes the software, the software causes the processing system 1314 to perform the various functions described above for any particular device. The computer-readable medium / memory 1306 can also be used to store data manipulated by the processor 1304 when executing the software. The processing system 1314 further includes at least one of components 1204, 1210, 1212, 1214, 1216. The components can be software components running in the processor 1304, resident / stored in the computer-readable medium / memory 1306, one or more hardware components coupled to the processor 1304, or some combination thereof. The processing system 1314 can be a component of the base station 310 and can include at least one of and / or a memory 376 of the TX processor 316, the RX processor 370, and the controller / processor 375.

[0145] In one configuration, the apparatus 1202 / 1202' for wireless communication includes: a unit for transmitting a first beam set. The apparatus 1202 / 1202' may further include: a unit for receiving a beam adjustment request on at least one resource. In one aspect, the at least one resource may include at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region. The apparatus 1202 / 1202' may further include: a unit for determining a beam index of a beam in the first beam set based on the at least one resource.

[0146] In one aspect, the beam adjustment request includes a request to transmit a BRRS. In one aspect, the apparatus 1202 / 1202' may further include: a unit for transmitting instructions for performing beam tracking based on the request and the determined beam index. In one aspect, the apparatus 1202 / 1202' may further include: a unit for performing beam tracking with a UE. In one aspect, the apparatus 1202 / 1202' may further include: a unit for transmitting a second beam set based on the determined beam index to perform beam tracking.

[0147] In one aspect, at least one resource is included on the PUCCH. In one aspect, at least one resource is included on a subframe associated with the RACH. In one aspect, at least one resource is included in a bandwidth associated with an RACH transmission. In one aspect, at least one resource is included in a bandwidth not reserved for RACH transmission. In one aspect, the bandwidth is reserved for scheduling request transmission. In one aspect, at least one resource indicates a range of indices, and the subcarriers of at least one resource indicate beam indices within the range.

[0148] In one aspect, the subframe of at least one resource indicates a range of indices, and apparatus 1202 / 1202' further includes: a unit for determining a beam index from within the range based on the strength of signals in different receive chains through which the base station receives the request.

[0149] The above unit may be one or more of the above components of apparatus 1202 and / or the processing system 1314 of apparatus 1202' configured to perform the functions recited by the above unit. As described above, the processing system 1314 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Accordingly, in one configuration, the above unit may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the above unit.

[0150] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is merely illustrative of an exemplary method. It should be understood that based on design preferences, the specific order or hierarchy of the blocks in the process / flowchart may be rearranged. Additionally, some blocks may be combined or omitted. The appended method claims present the elements of the various blocks in a sample order, but are not meant to be limited to the specific order or hierarchy presented.

[0151] The foregoing description is provided to enable any person skilled in the art to make and use the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but rather to the full scope consistent with the claims as expressed, where, unless explicitly stated otherwise, the mention of an element in the singular is not intended to mean "one and only one" but "one or more". The word "exemplary" as used herein means "serving as an example, instance, or illustration". Any aspect described herein as "exemplary" need not be construed as preferred or superior to other aspects. Unless otherwise explicitly stated, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "any combination of A, B, C, or thereof" include any combination of A, B, and / or C and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "any combination of A, B, C, or thereof" can be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combination can include one or more members or several members of A, B, or C. All structural and functional equivalents, known or later to be known to those of ordinary skill in the art, of the elements of the various aspects described throughout this disclosure are expressly incorporated herein by reference and are intended to be encompassed by the claims. Additionally, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is explicitly recited in the claims. The words "module", "mechanism", "element", "device", etc. may not be substitutes for the word "unit". Thus, no claim element is to be construed as a functional unit unless the element is expressly recited using the phrase "unit for...".

Claims

1. A method for wireless communication in a base station, the method comprising: Transmitting one or more signals on a first beam set; Receiving a beam adjustment request on at least one resource, the at least one resource corresponding to at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region, wherein the beam adjustment request is associated with the deterioration of a second beam corresponding to a second beam index; And Determining a first beam index of a first beam in the first beam set based on the at least one resource on which the beam adjustment request is received.

2. The method according to claim 1, wherein, The beam adjustment request includes a request for transmitting a beam refinement reference signal (BRRS).

3. The method according to claim 1, further comprising: Transmitting an instruction for performing beam tracking based on at least one of the beam adjustment request or the determined first beam index; And Performing beam tracking with a user equipment (UE).

4. The method according to claim 3, further comprising: Transmitting a second beam set based on the determined first beam index to perform the beam tracking.

5. The method according to claim 1, wherein The at least one resource corresponds to a physical uplink control channel (PUCCH).

6. The method according to claim 1, wherein The at least one resource corresponds to a subframe associated with a random access channel (RACH).

7. The method according to claim 1, wherein, The at least one resource corresponds to a bandwidth associated with RACH transmission.

8. The method according to claim 1, wherein The at least one resource corresponds to a bandwidth not reserved for RACH transmission.

9. The method according to claim 8, wherein, The bandwidth is reserved for scheduling request transmission.

10. The method according to claim 1, wherein, The at least one resource corresponds to a beam index range including the first beam index, and the subcarriers associated with the at least one resource correspond to the first beam index.

11. The method according to claim 10, wherein, The subframe associated with the at least one resource corresponds to a beam index range, and the method further comprises: Determining the first beam index from the range based on the respective strengths of the respective signals in different receive chains of the base station through which the beam adjustment request is received.

12. The method according to claim 1, further comprising: When the beam adjustment request indicates the deterioration of the second beam corresponding to the second beam index, switching communication with the user equipment (UE) from the second beam to the first beam.

13. An apparatus for wireless communication to be included in a base station, the apparatus comprising: A memory; And At least one processor coupled to the memory and configured to: Transmit one or more signals on a first beam set; Receive a beam adjustment request on at least one resource, the at least one resource corresponding to at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region, wherein the beam adjustment request is associated with the deterioration of a second beam corresponding to a second beam index; And Determine a first beam index of a first beam in the first beam set based on the at least one resource on which the beam adjustment request is received.

14. The apparatus according to claim 13, wherein, The beam adjustment request includes a request for transmitting a beam refinement reference signal (BRRS).

15. The device according to claim 13, wherein, The at least one processor is further configured to: Transmit an instruction for performing beam tracking based on at least one of the beam adjustment request or the determined first beam index; and Perform beam tracking with a user equipment (UE).

16. The apparatus according to claim 15, wherein, The at least one processor is further configured to: Transmit a second beam set based on the determined first beam index to perform the beam tracking.

17. The device according to claim 13, wherein, The at least one resource corresponds to a physical uplink control channel (PUCCH).

18. The apparatus according to claim 13, wherein, The at least one resource corresponds to a subframe associated with a random access channel (RACH).

19. The apparatus according to claim 13, wherein, The at least one resource corresponds to a bandwidth associated with RACH transmission.

20. The apparatus according to claim 13, wherein The at least one resource corresponds to a bandwidth not reserved for RACH transmission.

21. The apparatus according to claim 20, wherein, The bandwidth is reserved for scheduling request transmission.

22. The apparatus according to claim 13, wherein, The at least one resource corresponds to a beam index range including the first beam index, and the subcarriers associated with the at least one resource correspond to the first beam index.

23. The apparatus according to claim 22, wherein, The subframe associated with the at least one resource corresponds to a beam index range, and wherein the at least one processor is further configured to determine the first beam index from within the range based on the respective strengths of the respective signals in the respective receive chains of the base station through which the beam adjustment request is received.

24. The device according to claim 13, wherein, The at least one processor is further configured to: When the beam adjustment request indicates the deterioration of the second beam corresponding to the second beam index, switch communication with the user equipment (UE) from the second beam to the first beam.

25. An apparatus for wireless communication to be included in a base station, the apparatus comprising: A unit for transmitting one or more signals on a first beam set; A unit for receiving a beam adjustment request on at least one resource, the at least one resource corresponding to at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region, wherein the beam adjustment request is associated with the deterioration of a second beam corresponding to a second beam index; And A unit for determining a first beam index of a first beam in the first beam set based on the at least one resource on which the beam adjustment request is received.

26. The device according to claim 25, wherein, The beam adjustment request includes a request for transmitting a beam refinement reference signal (BRRS).

27. The apparatus according to claim 25, further comprising: A unit for transmitting an instruction for performing beam tracking based on at least one of the beam adjustment request or the determined first beam index; And A unit for performing beam tracking with a user equipment (UE).

28. The apparatus according to claim 27, further comprising: A unit for transmitting a second beam set based on the determined first beam index to perform the beam tracking.

29. The device according to claim 25, wherein, The at least one resource corresponds to a physical uplink control channel (PUCCH).

30. The apparatus according to claim 25, wherein, The at least one resource corresponds to a subframe associated with a random access channel (RACH).

31. The apparatus according to claim 25, wherein The at least one resource corresponds to a bandwidth associated with RACH transmission.

32. The apparatus according to claim 25, wherein, The at least one resource corresponds to a bandwidth not reserved for RACH transmission.

33. The apparatus according to claim 32, wherein, The bandwidth is reserved for scheduling request transmission.

34. The apparatus according to claim 25, wherein The at least one resource corresponds to a beam index range including the first beam index, and subcarriers associated with the at least one resource correspond to the first beam index.

35. The apparatus according to claim 34, wherein, A subframe associated with the at least one resource corresponds to the beam index range, and the apparatus further comprises: a unit configured to determine the first beam index from within the range based on respective strengths of respective signals in respective receiving chains of the base station through which the beam adjustment request is received.

36. The apparatus according to claim 25, further comprising: a unit configured to switch communication with a user equipment (UE) from the second beam to the first beam when the beam adjustment request indicates the deterioration of the second beam corresponding to the second beam index.

37. A non-transitory computer-readable medium storing computer-executable code for wireless communication by a base station, the computer-executable code including code for performing the following operations: transmitting one or more signals on a first beam set; Receive a beam adjustment request on at least one resource, where the at least one resource corresponds to at least one of a radio frame index, a subframe index, a symbol index, or a subcarrier region, wherein, The beam adjustment request is associated with the deterioration of a second beam corresponding to a second beam index; and determining a first beam index of a first beam in the first beam set based on the at least one resource on which the beam adjustment request is received.

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