Patent Description:
Wireless communications systems are widely deployed to provide various types of communications content such as voice, video, packet data, messaging, broadcast, and so on. By way of example, a wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, each otherwise known as user equipment (UE).

A base station may communicate with one or more UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.

An example of a telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA on the DL, SC-FDMA on the UL, and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. An example of an improvement to LTE technology is referred to as <NUM>. The term <NUM>, or new radio (NR), represents an evolution of LTE technology including, for example, various improvements to the wireless interface, processing improvements, and the enablement of higher bandwidth to provide additional features and connectivity. A feature of <NUM> is the use of millimeter wave (mmW) frequency bands and beam forming. Beam forming concentrates the radio energy in a narrow, selective (i.e., non-omnidirectional) pattern to increase gain without having to increase transmission power.

In a <NUM> mmW communication system, the transmitter and receiver continually determine the "best" beam path. That is, to optimize communication link quality between the transmitter and receiver, the transmitter forms an outgoing beam and the receiver forms an incoming beam that together best match the channel propagation conditions. As channel propagation conditions change, the transmitter and the receiver coordinate to transition, or switch, from one communication beam to another. A communication beam on which communication is actively occurring may be referred to as a "serving beam" and a communication beam on which communication is to transition to may be referred to as a "target beam" or a "candidate beam.

A challenge in transitioning from one communication beam to another is that the beamforming is typically performed by radio frequency (RF) components, some of which operate in the analog domain. Transitioning from one beam to another consumes a period of time during which the analog components are reconfigured to operate on the new communication beam. The beam switch time refers to a delay measured from the beam switch command or trigger, to the time it takes the components to reconfigure to the new communication beam, sometimes referred to as settling time. The beam switch time may consume hundreds of nanoseconds (ns), which may exceed the amount of time allocated to a cyclic prefix (CP) portion of a communication symbol, during which beam transition typically occurs. This may cause the CP portion of a communication symbol to exceed (or leak into) the payload portion of the communication symbol and may cause additional intersymbol interference (ISI) in the payload.

Therefore, increasing an amount of time available for communication beam transition is desirable. <CIT> describes methods and apparatus for cyclic prefix reduction in mmwave mobile communication systems. <CIT> describes schemes for access links of systems operating in higher frequency bands. <NPL> describes aspects of time domain structures. <NPL> describes CSI-RS design for DL Beam management.

Various implementations of systems, methods, and apparatuses within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the desirable attributes described herein. Without limiting the scope of the appended claims, some prominent features are described herein.

Note that relative dimensions of elements depicted in the drawing figures may not be to scale.

In the drawings, like reference numerals refer to like parts throughout the various views unless otherwise indicated. For reference numerals with letter character designations such as "102A" or "102B", the letter character designations may differentiate two like parts or elements present in the same figure. Letter character designations for reference numerals may be omitted when it is intended that a reference numeral to encompass all parts having the same reference numeral in all figures.

For instance, the methods described herein may be performed in an order different from that described, and various steps may be added, omitted, or combined.

Examples described below are directed to lengthening a period of time for communication beam transition by adjusting sub-carrier (also referred to as "tone") frequency spacing to provide less frequency bandwidth per tone for selected communication symbols that may follow a communication beam switch location in time and/or precede a communication beam switch location in time. Such selected communication symbols may include, but are not limited to, those carrying a demodulation reference signal (DMRS), channel state information-reference signal (CSI-RS), and a communication having a modulation and coding scheme (MCS) having a high reliability requirement, and other selected signals. As used heren, the terms "beam transition" and "beam switch" may be used interchangeably.

Embodiments include determining a location in time in a transmission time interval (TTI), or in a communication frame, a communication sub-frame, a communication slot, etc., where a beam switch, or a beam transition is to occur, and then determining the content of the communication symbol or symbols immediately preceding the beam switch location and/or immediately following the beam switch location. If the communication symbol or symbols immediately preceding the beam transition location or immediately following the beam transition location are one of selected communication symbols that may benefit from a longer communication beam transition period, then the sub-carrier frequency spacing is adjusted for the selected communication symbol, or communication symbols, resulting in a new communication symbol having a longer length beam transition period within which to perform the beam transition. The longer length beam transition period results in a longer guard period, that may include additional time for the beam transition to occur. The longer guard period may also include the time for a CP to be applied to the communication symbol after the beam transition is complete and before the payload portion of the communication symbol begins, thereby minimizing the chance that the CP may leak into the payload portion of the communication symbol.

<FIG> illustrates an example of a wireless communications system <NUM> in accordance with various aspects of the disclosure. The wireless communications system <NUM> includes base stations <NUM>, UEs <NUM>, and a core network <NUM>. The base stations <NUM> interface with the core network <NUM> through a first set of backhaul links <NUM> (e.g., S1, etc.) and may perform radio configuration and scheduling for communication with the UEs <NUM>, or may operate under the control of a base station controller (not shown). In various examples, base stations <NUM> may communicate, either directly or indirectly (e.g., through core network <NUM>), with each other over a second set of backhaul links <NUM> (e.g., X1, etc.), which may be wired or wireless communication links.

Each base station site may provide communication coverage for a respective geographic coverage area <NUM>. In some examples, base stations <NUM> may be referred to as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, a gNodeB, or some other suitable terminology. The geographic coverage area <NUM> for a base station <NUM> may be divided into sectors making up only a portion of the coverage area (not shown). Wireless communications system <NUM> may include base stations <NUM> of different types (e.g., macro and/or small cell base stations). There may be overlapping geographic coverage areas <NUM> for different technologies.

In some examples, wireless communications system <NUM> may be one or more of an LTE/LTE-A network and a <NUM> network. In LTE/LTE-A networks, the term evolved Node B (eNB) or in a <NUM> (also referred to as new radio (NR)) network, the term millimeter wave B (mWB), or gNodeB (gNB) may be generally used to describe base stations <NUM>, while the term UE may be generally used to describe UEs <NUM>. Wireless communications system <NUM> may be a heterogeneous LTE/LTE-A and <NUM> network in which different types of eNBs and/or mWBs provide coverage for various geographical regions. For example, each eNB, mWB, gNB, or base station <NUM> may provide communication coverage for a macro cell, a small cell, and/or other types of cell. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context. In some examples, wireless communications system <NUM> may be, or may include a millimeter wave communication network.

A pico cell may cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell also may cover a relatively small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB.

Wireless communications system <NUM> may support synchronous or asynchronous operation. For synchronous operation, base stations <NUM> may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, base stations <NUM> may have different frame timing, and transmissions from different base stations may not be aligned in time.

The communication networks that may accommodate some of the various disclosed examples may be packet-based networks that operate according to a layered protocol stack. The MAC layer may also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE <NUM> and the base stations <NUM> or core network <NUM> supporting radio bearers for the user plane data. At the Physical (PHY) layer, the transport channels may be mapped to Physical channels.

The UEs <NUM> are dispersed throughout the wireless communications system <NUM>, and each UE <NUM> may be stationary or mobile. A UE <NUM> may also include or be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. A UE <NUM> may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, mWBs, relay base stations, and the like. A UE <NUM> may also be able to communicate with other UEs either within or outside the same coverage area of a base station via D2D communications.

The communication links <NUM> shown in wireless communications system <NUM> may include uplink (UL) transmissions from a UE <NUM> to a base station <NUM>, and/or downlink (DL) transmissions, from a base station <NUM> to a UE <NUM>. The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link <NUM> may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies) modulated according to the various radio technologies described above. Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links <NUM> may transmit bidirectional communications using FDD (e.g., using paired spectrum resources) or TDD operation (e.g., using unpaired spectrum resources). Frame structures for FDD (e.g., frame structure type <NUM>) and TDD (e.g., frame structure type <NUM>) may be defined.

In some examples, base stations <NUM> and/or UEs <NUM> may include multiple antennas for employing antenna diversity schemes to improve communication quality and reliability between base stations <NUM> and UEs <NUM>. Additionally or alternatively, base stations <NUM> and/or UEs <NUM> may employ multiple-input, multiple-output (MIMO) techniques that may take advantage of multi-path environments to transmit multiple spatial layers carrying the same or different coded data.

<FIG> is a block diagram of a UE <NUM>, in accordance with various aspects of the present disclosure. The UE <NUM> may be an example of one or more aspects of UE <NUM> described above with reference to <FIG>. As UE <NUM> serves as a transceiver, it has a transmitter portion <NUM> and a receiver portion <NUM>. Although some examples described in this disclosure may relate to transmitting while other examples may relate to receiving, waveform shaping principles described in relation to transmitting also apply to receiving, and waveform shaping principles described in relation to receiving also apply to transmitting.

The UE <NUM> may include one or more antennas <NUM>, RF front end circuitry <NUM>, and baseband system circuitry <NUM>. Transmitter portion <NUM> includes channel coding logic <NUM> that encodes data <NUM>, modulation logic <NUM> that modulates the encoded data provided by channel coding logic <NUM>, and waveform synthesis logic <NUM> that synthesizes or generates baseband transmit (TX) signals. The RF front end circuitry <NUM> upconverts the baseband TX signals provided by waveform synthesis logic <NUM> to radio frequency (RF) for transmission via antennas <NUM>. Portions of baseband system circuitry <NUM> that provide data <NUM> to be transmitted are not shown for purposes of clarity but are well understood by one of ordinary skill in the art. The RF front end circuitry <NUM> also downconverts RF signals received from antennas <NUM> to baseband and provides the resulting baseband receive (RX) signals to receiver portion <NUM>. Receiver portion <NUM> includes waveform analysis logic <NUM> that analyzes or receives the baseband RX signals, demodulation logic <NUM> that demodulates the received signals provided by waveform analysis logic <NUM>, and channel decoding logic <NUM> that decodes the demodulated signals provided by demodulation logic <NUM>. Portions of baseband system circuitry <NUM> that further process the decoded data <NUM> provided by channel decoding logic <NUM> are not shown for purposes of clarity but are well understood by one of ordinary skill in the art.

Various modulation and waveform synthesis schemes may be used. For example, modulation logic <NUM> and demodulation logic <NUM> may be configured in accordance with quadrature amplitude modulation (QAM). As well understood by one of ordinary skill in the art, QAM independently modulates each sub-carrier or tone with (encoded) baseband data. Waveform synthesis logic <NUM> and waveform analysis logic <NUM> may be configured in accordance with, for example, OFDM. As well understood by one of ordinary skill in the art, OFDM generates multiple orthogonally spaced sub-carrier signals or tones corresponding to multiple information channels.

<FIG> is a block diagram of OFDM waveform synthesis logic <NUM>, in accordance with various aspects of the present disclosure. The OFDM waveform synthesis logic <NUM> may be an example of one or more aspects of waveform synthesis logic <NUM> described above with reference to <FIG>. The OFDM waveform synthesis logic <NUM> may include a transform section <NUM> and a waveform shaper <NUM>. Transform section <NUM> may operate upon center tones <NUM>, head tones <NUM>, and tail tones <NUM>. Center tones <NUM> comprise a group or range of multiple sub-carriers or tones that lie between head tones <NUM> (i.e., another group or range of multiple sub-carriers or tones lower than center tones <NUM> in frequency), and tail tones <NUM> (i.e., still another group or range of multiple sub-carriers or tones higher than center tones <NUM> in frequency).

Transform section <NUM> includes IFFT logic <NUM> that converts or transforms head tones <NUM> from the frequency domain to the time domain. Transform section <NUM> not only performs such a transform but also may perform ancillary functions. For example, transform section <NUM> may also include a parallel-to-serial converter <NUM> that converts the output signals provided by IFFT logic from a parallel format to a serial format. Transform section <NUM> may also include, for example, extension logic <NUM> that adds a cyclic prefix (CP) and an extension (EXT) to the serial output signals provided by parallel-to-serial converter <NUM>. As well understood by one of ordinary skill in the art, a cyclic prefix is a part of the symbol (or sub-symbol in the case of separate processing paths for center tones <NUM>, head tones <NUM>, and tail tones <NUM>) that is copied from one end of the symbol and appended to the other end. This process of adding a cyclic prefix helps to reduce inter-symbol interference (ISI). An additional extension may also be added for the overlap- and-add operation across successive symbols over time. Transform section <NUM> may similarly include another path comprising IFFT logic <NUM>, a parallel-to-serial converter <NUM>, and extension logic <NUM>, which together process center tones <NUM>. Transform section <NUM> may similarly include still another path comprising IFFT logic <NUM>, a parallel-to-serial converter <NUM>, and extension logic <NUM>, which together process tail tones <NUM>.

Waveform shaper <NUM> may include a head tone processor <NUM> configured to process head tones <NUM> (as transformed by transform section <NUM>) using a first waveform shaping characteristic, a tail tone processor <NUM> configured to process tail tones <NUM> (as transformed by transform section <NUM>) using a second waveform shaping characteristic, and a center tone processor <NUM> configured to process center tones <NUM> (as transformed by transform section <NUM>) using a third waveform shaping characteristic. Significantly, in this example, the first, second, and third waveform shaping characteristics may be different from each other or "asymmetric. " The output of each of head tone processor <NUM>, tail tone processor <NUM>, and center tone processor <NUM> comprises a sequence or stream of sub-symbols. A combiner <NUM> is configured to combine a first sub-symbol provided by head tone processor <NUM>, a second sub-symbol provided by center tone processor <NUM>, and a third sub-symbol provided by tail tone processor <NUM> into an output symbol. As described below with regard to <FIG>, in some examples combiner <NUM> may comprise an aligner and sub-symbol adder <NUM> and an overlapper and symbol adder <NUM>. The output of combiner <NUM> may comprise a sequence or stream of symbols.

<FIG> is a block diagram of Discrete Fourier Transform-spread OFDM (DFT-s-OFDM) waveform synthesis logic <NUM>, in accordance with various aspects of the present disclosure. The DFT-s-OFDM waveform synthesis logic <NUM> may be an example of one or more aspects of above-described OFDM waveform synthesis logic <NUM> (<FIG>) or <NUM> (<FIG>). The DFT-s-OFDM waveform synthesis logic <NUM> may include a transform section <NUM> and a WOLA waveform shaper <NUM>. As transform section <NUM> may be similar to above-described transform section <NUM> (<FIG>), transform section <NUM> may include IFFT logic <NUM>, a parallel-to-serial converter <NUM>, and extension logic <NUM>, which together process head tones, IFFT logic <NUM>, a parallel-to-serial converter <NUM>, and extension logic <NUM>, which together process center tones, and IFFT logic <NUM>, a parallel-to-serial converter <NUM>, and extension logic <NUM>, which together process tail tones.

<FIG> also illustrates that in accordance with DFT-spread OFDM principles, the source of the head tones, center tones, and tail tones may comprise, for example, FFT logic <NUM> and a sub-carrier mapper <NUM>. A serial-to-parallel conversion operation may also occur between the input of FFT logic <NUM> and the output of a modulator, such as modulation logic <NUM> (<FIG>), but is not shown for purposes of clarity. The FFT logic <NUM> may perform an M-point FFT on a time-domain symbol block, where M is the total number of discrete tones (i.e., head tones, center tones, and tail tones). Sub-carrier mapper <NUM> then allocates or maps the tones provides by FFT logic <NUM> to the total set of sub-carriers.

The WOLA waveform shaper <NUM> processes head tones by applying head tone weighting function <NUM>, processes center tones by applying center tone weighting function <NUM>, and processes tail tones by applying tail tone weighting function <NUM>. Head tone weighting function <NUM>, center tone weighting function <NUM>, and tail tone weighting function <NUM> may be different from each other. A combiner <NUM> may combine the weighted sub-symbols provided by head tone weighting function <NUM>, center tone weighting function <NUM>, and tail tone weighting function <NUM>. Combiner <NUM> may include an aligner and sub-symbol adder <NUM> configured to align (in the time domain) a weighted head tone sub-symbol provided by head tone weighting function <NUM>, a weighted center tone sub-symbol provided by center tone weighting function <NUM>, and a weighted tail tone sub-symbol provided by tail tone weighting function <NUM> and add or sum them to form a symbol. Combiner <NUM> may further includes an overlapper and symbol adder <NUM> configured to overlap and add two successive symbols.

<FIG> is a diagram <NUM> illustrating an example of a DL frame structure in LTE. A frame (<NUM>) may be divided into <NUM> equally sized subframes. Each subframe may include two consecutive time slots. A resource grid may be used to represent two time slots, each time slot including a resource block. The resource grid is divided into multiple resource elements. In LTE, for a normal cyclic prefix, a resource block contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive OFDM symbols in the time domain, for a total of <NUM> resource elements. For an extended cyclic prefix, a resource block contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive OFDM symbols in the time domain, for a total of <NUM> resource elements. In other exemplary communication systems, such as, for example, a <NUM> or a NR communication system, other numbers of subcarriers in the frequency domain and symbols in the time domain, providing other numbers of resource elements are possible. Some of the resource elements, indicated as R <NUM>, <NUM>, include DL reference signals (DL-RS). The DL-RS include Cell-specific RS (CRS) (also sometimes called common RS) <NUM> and UE-specific RS (UE-RS) <NUM>. UE-RS <NUM> are transmitted on the resource blocks upon which the corresponding physical DL shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate for the UE.

<FIG> is a diagram <NUM> illustrating an example of an UL frame structure in LTE. The available resource blocks for the UL may be partitioned into a data section and a control section. The control section may be formed at the two edges of the system bandwidth and may have a configurable size. The resource blocks in the control section may be assigned to UEs for transmission of control information. The data section may include all resource blocks not included in the control section. The UL frame structure results in the data section including contiguous subcarriers, which may allow a single UE to be assigned all of the contiguous subcarriers in the data section.

A UE may be assigned resource blocks 610a, 610b in the control section to transmit control information to an eNB/gNB. The UE may also be assigned resource blocks 620a, 620b in the data section to transmit data to the eNB/gNB. The UE may transmit control information in a physical UL control channel (PUCCH) on the assigned resource blocks in the control section. The UE may transmit data or both data and control information in a physical UL shared channel (PUSCH) on the assigned resource blocks in the data section. A UL transmission may span both slots of a subframe and may hop across frequency.

A set of resource blocks may be used to perform initial system access and achieve UL synchronization in a physical random access channel (PRACH) <NUM>. The PRACH <NUM> carries a random sequence and cannot carry any UL data/signaling. Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks. The starting frequency is specified by the network. That is, the transmission of the random access preamble is restricted to certain time and frequency resources. There is no frequency hopping for the PRACH. The PRACH attempt is carried in a single subframe (<NUM>) or in a sequence of few contiguous subframes and a UE can make a single PRACH attempt per frame (<NUM>).

<FIG> is a block diagram <NUM> of a communication system including a base station <NUM> and a UE <NUM> for use in wireless communication, in accordance with various aspects of the present disclosure. The base station <NUM> may be an example of one or more aspects of a base station described with reference to <FIG>. The UE <NUM> may be an example of one or more aspects of a UE described with reference to <FIG>.

The UE <NUM> may be in bi-directional wireless communication with the base station <NUM>. In an exemplary embodiment, the UE <NUM> may be in bi-directional wireless communication with the base station <NUM> over a serving beam <NUM>, which may also be referred to as a beam pair link (BPL) <NUM>. A serving beam may be a communication beam that conveys control information, referred to as a control beam, may be a communication beam that conveys data, referred to as a data beam, or may be other communication beams. In an exemplary embodiment, the serving beam <NUM> may comprise a transmit beam sent from the base station <NUM> and a receive beam tuned to by the UE <NUM>, and may comprise a transmit beam sent by the UE <NUM> and a receive beam tuned to by the base station <NUM>. The BPL <NUM> is intended to depict bi-directional communication between the UE <NUM> and the base station <NUM> using a combination of transmit and receive beams that cooperate to create the bi-directional communication link. In an exemplary embodiment, the serving beam <NUM> may be one of a plurality of directional communication beams that may be configured to operatively couple the UE <NUM> to the base station <NUM>. In an exemplary embodiment, at a given time, the serving beam <NUM>, and BPL <NUM>, may be able to provide the most robust communication link between the UE <NUM> and the base station <NUM>.

In an exemplary embodiment, other serving beams may also be established between a UE <NUM> and the base station <NUM>. For example, serving beams <NUM> may establish a BPL <NUM> between the UE <NUM> and the base station <NUM>; and serving beam <NUM> may establish a BPL <NUM> between the UE <NUM> and the base station <NUM>.

In an exemplary embodiment, one or more target or candidate beams may also be available to provide a communication link between the UE <NUM> and the base station <NUM>. In an exemplary embodiment, the candidate beam <NUM> represents one of a plurality of available candidate beams, and is shown in dotted line to indicate that it is not actively providing an operative communication link between the UE <NUM> and the base station <NUM>.

<FIG> is a block diagram <NUM> of a communication system including a base station <NUM> and a UE <NUM> for use in wireless communication, in accordance with various aspects of the present disclosure. <FIG> illustrates transition from a serving beam to a candidate beam. For example, in <FIG>, the BPL <NUM> and/or the BPL <NUM> have experienced radio link failure (RLF), or may soon experience RLF, in that they are unable to continue to establish, or maintain a radio communication link between the UE <NUM> and the base station <NUM>. However, a candidate, or target, beam <NUM> and the BPL <NUM>, may be available for communication.

The example shown in <FIG> shows an exemplary embodiment of communication beam transition. For example, the UE <NUM> may generate and periodically transmit to the base station <NUM> beam information including, for example, a beam index (BI) report listing information relating to the serving beam <NUM> and one or more available target beams <NUM> of which the UE <NUM> may be aware. In an exemplary embodiment, the BI report may include the identity of one or more candidate beams, such as candidate beam <NUM> of which the UE <NUM> may be aware, and which may be available to provide a communication link between the base station <NUM> and the UE <NUM> should the quality of the serving beam <NUM> degrade to a point at which radio link failure (RLF) may be imminent.

<FIG> shows a system <NUM> for use in wireless communication, in accordance with various aspects of the present disclosure. The system <NUM> may include a base station <NUM>, which may be an example of the base station <NUM> of <FIG>. The base station <NUM> may comprise <NUM> circuitry <NUM>, and other communication circuitry (not shown). Some of the operational elements of the <NUM> circuitry <NUM> may be omitted for ease of description, and are known to those having ordinary skill in the art.

The base station <NUM> may generally include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. The base station <NUM> may include an antenna <NUM> coupled to the <NUM> circuitry <NUM>. The antenna <NUM> may comprise one or more antenna elements, may comprise an array, or a phased array, of antenna elements, and may comprise one or more directional and/or omni-directional antenna elements, which may be controlled individually or in groups of two or more elements. The <NUM> circuitry <NUM> may be configured to establish a <NUM> communication channel with a device, such as a UE <NUM> (not shown). In an exemplary embodiment, the communication channel may comprise the serving beam <NUM> and one or more target beams <NUM>.

The <NUM> circuitry <NUM> may comprise a baseband system <NUM> and a radio frequency integrated circuit (RFIC) <NUM>, operatively coupled together over a bi-directional connection <NUM>. The baseband system <NUM> may comprise a processor <NUM>, a memory <NUM> (including software (SW) <NUM>), and a beam transition module <NUM>, which may communicate, directly or indirectly, with each other (e.g., via one or more buses <NUM>). The RFIC <NUM> may comprise an intermediate frequency (IF) sub-system <NUM> and a transceiver module <NUM> operatively coupled together over a bi-directional connection <NUM>. The RFIC <NUM> may comprise one or more digital components and one or more analog components, such as, for example, phase shifters, switches, or other components configured for beamforming. In an exemplary embodiment, the transceiver module <NUM> may be configured to communicate over millimeter wave (mmW) frequencies. The transceiver module <NUM> may communicate bi-directionally, via the antenna(s) <NUM> and/or one or more wired or wireless links, with one or more networks, as described above. For example, the transceiver module <NUM> may communicate bi-directionally with UEs <NUM> (not shown). One or more of the analog components in the transceiver module <NUM> may be used when transitioning from one communication beam to another communication beam. In an exemplary embodiment, the "beam switch time" or "beam transition time" refers to a delay between the triggering of the transition from a serving communication beam to a target communication beam to the final settling time on the target communication beam, and typically may take hundreds of nanoseconds (ns). Such hundreds of ns delay time can be significant as mmW communication uses variable and sometimes wider sub-carrier frequency spacing than does LTE, which allows less time for the CP in a mmW communication system compared with LTE.

The transceiver module <NUM> may include a modem to modulate the packets and provide the modulated packets to the antenna(s) <NUM> for transmission, and to demodulate packets received from the antenna(s) <NUM>. While the base station <NUM> may include a single antenna <NUM> the base station <NUM> may have multiple antennas capable of concurrently transmitting and/or receiving multiple wireless transmissions via carrier aggregation techniques, for example. The transceiver module <NUM> may be capable of concurrently communicating with one or more UEs <NUM> via multiple component carriers.

The base station <NUM> may include a beam transition module <NUM>, which may perform the beam transition functions described herein. In an exemplary embodiment, the beam transition module <NUM> may be configured to cooperate with the processor <NUM> and the memory <NUM> to allow the base station <NUM> to communicate with a UE <NUM> to transition from a serving beam <NUM> to a target beam <NUM> as described herein.

In an exemplary embodiment, the beam transition module <NUM> may comprise an optional beam switch completion time reception logic <NUM> configured to process a beam transition completion time communication from another communication device, such as from a UE <NUM>. In an exemplary embodiment, the beam transition module <NUM> may also comprise a beam switch location determination logic <NUM>, a symbol configuration determination logic <NUM> and a symbol configuration transmission logic <NUM>.

In an exemplary embodiment, the beam switch location determination logic <NUM> may be configured to identify a location in time in a communication transmission time interval (TTI) where a communication beam transition will occur.

In an exemplary embodiment, the symbol configuration determination logic <NUM> may be configured to determine a configuration of a communication symbol at least partly based on the identified beam transition location and a priority of the communication symbol, where in the configuration an extended guard period is created by changing the sub-carrier frequency spacing of at least one of the communication symbols following and/or preceding the beam transition location.

In an exemplary embodiment, symbol configuration transmission logic <NUM> may be configured to send the configuration of the communication symbol in a signaling communication to a second communication device.

Although shown as a separate logic elements in <FIG>, the instructions associated with the logic elements in the beam transition module <NUM> may be partly or wholly stored in the memory <NUM> for execution by the processor <NUM>. The logic elements in the beam transition module <NUM> may be software, firmware, or a combination of software and firmware that can be configured and executed by the processor <NUM> to perform the functons described herein.

The memory <NUM> may include random access memory (RAM) and read-only memory (ROM). The memory <NUM> may store computer-readable, computer-executable software/firmware code <NUM> containing instructions that, when executed, cause the processor <NUM> to perform various functions described herein (e.g., perform synchronization operations, synchronize reference timing parameters, beam transition operations, etc.). Alternatively, the computer-readable, computer-executable software/firmware code <NUM> may not be directly executable by the processor <NUM> but cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor <NUM> may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc..

Although the logic elements associated with the beam transition module <NUM> are described in <FIG> in a conceptual manner as stored in or residing in the memory <NUM>, persons skilled in the art understand that such logic elements arise through the operation of the processor <NUM> in accordance with conventional computing device principles. That is, software, firmware, or a combination of software and firmware contributes to programming or configuring the processing system to be characterized by such logic elements. Although the memory <NUM> is depicted in <FIG> as a single or unitary element for purposes of clarity, the memory <NUM> can be of any suitable type and can have any suitable structure, such as one or more modules, chips, etc. Likewise, although the processor <NUM> is depicted in <FIG> as a single or unitary element for purposes of clarity, the processor <NUM> can be of any suitable type and can have any suitable structure, such as one or more modules, chips, etc. For example, the processor <NUM> can comprise one or more microprocessors or microcontrollers. Some or all of the foregoing processing system elements can be provided in, for example, an application-specific integrated circuit (ASIC) or other integrated digital device. It should be understood that the combination of the memory <NUM> and the above-referenced modules or software, firmware, instructions, etc., underlying the logic elements, as stored in the memory <NUM> in non-transitory computer-readable form, defines a "computer program product" as that term is understood in the patent lexicon. In view of the descriptions herein, persons skilled in the art will readily be capable of providing suitable software or firmware or otherwise configuring the base station <NUM> to operate in the manner described. Also, although the effect of each of the above-referenced logic elements is described herein, it should be understood that the effect may result from contributions of two or more logic elements in concert, or from contributions of the logic elements and conventional switch logic elements or other software, hardware, or network elements that are not shown for purposes of clarity.

<FIG> shows a system <NUM> for use in wireless communication, in accordance with various aspects of the present disclosure. The system <NUM> may include a UE <NUM>, which may be an example of the UE <NUM> of <FIG>. The UE <NUM> may comprise <NUM> circuitry <NUM> and other communication circuitry (not shown). Some of the operational elements of the <NUM> circuitry <NUM> may be omitted for ease of description, and are known to those having ordinary skill in the art.

The UE <NUM> may generally include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. The UE <NUM> may include an antenna <NUM> coupled to the <NUM> circuitry <NUM>. The antenna <NUM> may comprise one or more antenna elements, may comprise an array, or a phased array, of antenna elements, and may comprise one or more directional and/or omni-directional antenna elements, which may be controlled individually or in groups of two or more elements. The <NUM> circuitry <NUM> may be configured to establish a <NUM> communication channel with a base station <NUM> (not shown). In an exemplary embodiment, the communication channel may comprise the serving beam <NUM> and one or more target beams <NUM>.

The <NUM> circuitry <NUM> may comprise a baseband system <NUM> and a radio frequency integrated circuit (RFIC) <NUM> operatively coupled together over a bi-directional connection <NUM>. The baseband system <NUM> may comprise a processor <NUM>, a memory <NUM> (including software (SW) <NUM>), and a beam transition module <NUM>, which each may communicate, directly or indirectly, with each other (e.g., via one or more buses <NUM>). The RFIC <NUM> may comprise an intermediate frequency (IF) sub-system <NUM> and a transceiver module <NUM> operatively coupled together over a bi-directional connection <NUM>. The RFIC <NUM> may comprise one or more digital components and one or more analog components, such as, for example, phase shifters, switches, or other components configured for beamforming. One or more of the analog components in the transceiver module <NUM> may be used when transitioning from one communication beam to another communication beam. In an exemplary embodiment, the "beam switch time" or "beam transition time" refers to a delay from triggering the change of beams to the final settling time, and typically may take hundreds of nanoseconds (ns). Such hundreds of ns delay time can be significant as mmW uses variable and sometimes wider tone spacing than does LTE, which allows less time for the CP in a mmW communication system compared with LTE, as mentioned above.

In an exemplary embodiment, the transceiver module <NUM> may be configured to communicate over millimeter wave (mmW) frequencies. The transceiver module <NUM> may communicate bi-directionally, via the antenna(s) <NUM> and/or one or more wired or wireless links, with one or more networks, as described above. For example, the transceiver module <NUM> may communicate bi-directionally with base stations <NUM> (not shown), with other UEs <NUM>, and/or with devices <NUM>. The transceiver module <NUM> may include a modem to modulate the packets and provide the modulated packets to the antenna(s) <NUM> for transmission, and to demodulate packets received from the antenna(s) <NUM>. While the UE <NUM> may include a single antenna <NUM> for the <NUM> circuitry <NUM>, the UE <NUM> may have multiple antennas capable of concurrently transmitting and/or receiving multiple wireless transmissions via carrier aggregation techniques, for example. The transceiver module <NUM> may be capable of concurrently communicating with one or more base stations <NUM> via multiple component carriers.

The UE <NUM> may include a beam transition module <NUM>, which may perform the beam transition functions described herein. In an exemplary embodiment, the beam transition module <NUM> may be configured to communicate with a base station <NUM> to transition from a serving beam <NUM> to a target beam <NUM> as described herein.

In an exemplary embodiment, the beam transition module <NUM> may comprise an optional beam switch completion time reporting logic <NUM> configured to generate and report a communicaton beam transition completion time capability to another communication device, such as to a base staion (gNB). In an exemplary embodiment, the beam transition module <NUM> may also comprise a beam switch location reception logic <NUM>, a beam switch location identification logic <NUM> and a symbol configuration application logic <NUM>.

In an exemplary embodiment, the optional beam switch completion time reporting logic <NUM> may be configured to generate and report a communicaton beam transition completion time capability to another communication device, such as to a base staion (gNB).

In an exemplary embodiment, the beam switch location reception logic <NUM> may be configured to process a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI).

In an exemplary embodiment, the beam switch location identification logic <NUM> may be configured to identify the beam transition location at least in part based on the received signal in the TI.

In an exemplary embodiment, the symbol configuration application logic <NUM> may be configured to determine a configuration of a communication symbol at least partly based on the received signaling and/or a predefined method, where in the configuration an extended guard period may be created for a symbol by changing the sub-carrier frequency spacing of at least one of the symbols following and/or preceding the identified beam transition location, so that the sub-carrier frequency spacing for the symbol immediately following and/or preceding the beam transition location is different than the sub-carrier frequency spacing for a symbol that does not immediately precede and/or follow the beam transition location. In an exemplary embodiment, the communication configuration may be at least partly determined by the capability reported by the optional beam switch completion time reporting logic <NUM>. As used herein, the term "predefined method" may comprise, for example, a procedure that may be defined in a communication standard, for example, the 3GPP standard, which both a UE and a base station may be configured to perform. For example, a predefined method in a communication standard may define that in an implementation having an extended CP length, no adjustment of sub-carrier frequency spacing is performed, while in an implementation having a normal CP length, the sub-carrier frequency spacing may be adjusted. For example, the sub-carrier frequency spacing may be adjusted if the modulation and coding scheme for the PDSCH communication following the beam switch time is larger than a threshold, and/or if the sub-carrier frequency spacing is above a threshold, e.g., <NUM>. In such an example, without further signaling, both a base station and a UE may determine whether to adjust the sub-carrier frequency spacing based on such a predefined method in the standard.

Although shown as a separate logic elements in <FIG>, the instructions associated with the elements in the beam transition module <NUM> may be partly or wholly stored in the memory <NUM> for execution by the processor <NUM>.

The logic elements in the beam transition module <NUM> may be software, firmware, or a combination of software and firmware that can be configured and executed by the processor <NUM> to perform the functons described herein.

Although the logic elements associated with the beam transition module <NUM> are described in <FIG> in a conceptual manner as stored in or residing in the memory <NUM>, persons skilled in the art understand that such logic elements arise through the operation of the processor <NUM> in accordance with conventional computing device principles. That is, software, firmware, or a combination of software and firmware contributes to programming or configuring the processing system to be characterized by such logic elements. Although the memory <NUM> is depicted in <FIG> as a single or unitary element for purposes of clarity, the memory <NUM> can be of any suitable type and can have any suitable structure, such as one or more modules, chips, etc. Likewise, although the processor <NUM> is depicted in <FIG> as a single or unitary element for purposes of clarity, the processor <NUM> can be of any suitable type and can have any suitable structure, such as one or more modules, chips, etc. For example, the processor <NUM> can comprise one or more microprocessors or microcontrollers. Some or all of the foregoing processing system elements can be provided in, for example, an application-specific integrated circuit (ASIC) or other integrated digital device. It should be understood that the combination of the memory <NUM> and the above-referenced modules or software, firmware, instructions, etc., underlying the logic elements, as stored in the memory <NUM> in non-transitory computer-readable form, defines a "computer program product" as that term is understood in the patent lexicon. In view of the descriptions herein, persons skilled in the art will readily be capable of providing suitable software or firmware or otherwise configuring the UE <NUM> to operate in the manner described. Also, although the effect of each of the above-referenced logic elements is described herein, it should be understood that the effect may result from contributions of two or more logic elements in concert, or from contributions of the logic elements and conventional switch logic elements or other software, hardware, or network elements that are not shown for purposes of clarity.

<FIG> is a diagram showing a <NUM> communication frame structure <NUM> with <NUM> sub-carrier spacing. A <NUM> radio frame may support variable sub-carrier spacing. For example, a <NUM> radio frame may have sub-carrier spacing of <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. The sub-carrier spacing is related to symbol length and the term "numerology" as used herein refers to the sub-carrier spacing and symbol length of a communication symbol. The frame structure <NUM> shows a <NUM> sub-carrier spacing and shows one (<NUM>) radio frame <NUM> having ten (<NUM>) subframes <NUM>, which equates to <NUM> slots and a time duration of <NUM> milliseconds (ms). Each subframe <NUM> may comprise <NUM> slots <NUM> and have a duration of <NUM>. Each slot <NUM> may comprise <NUM> communication symbols <NUM>, with each symbol having a duration of <NUM>.

<FIG> is a diagram showing a <NUM> communication frame structure <NUM> with <NUM> sub-carrier spacing. The frame structure <NUM> shows a <NUM> sub-carrier spacing and shows one (<NUM>) radio frame <NUM> having ten (<NUM>) subframes <NUM>, which equates to <NUM> slots and a time duration of <NUM> milliseconds (ms). Each subframe <NUM> may comprise <NUM> slots <NUM> and have a duration of <NUM>. Each slot <NUM> may comprise <NUM> communication symbols <NUM>, with each symbol having a duration of <NUM>. As the sub-carrier spacing is reduced, the time duration of each symbol is lengthened. As shown above, the time duration of a communication symbol <NUM> at <NUM> sub-carrier spacing is <NUM> and the time duration of a communication symbol <NUM> at <NUM> sub-carrier spacing is <NUM>. Other sub-carrier spacing leads to other communication symbol lengths.

<FIG> shows an exemplary communication slot <NUM> in accordance with various aspects of the present disclosure. The communication slot <NUM> may occur within a transmission time interval (TTI), and may occupy an entire TTI, or may occupy less than one TTI, or alternatively, a TTI may have a duration that is less than a duration of the slot <NUM>.

The communication slot <NUM> comprises a number of communication symbols <NUM>, labeled symbols <NUM> through <NUM> in this example, in am exemplary sub-carrier <NUM>. In an exemplary embodiment of the disclosure, a communication beam switch may occur, or be scheduled to occur at any point during the communication slot <NUM>. A beam switch or a beam transition may comprise a change in the transmission configuration indicator (TCI) of the transmission. In this example, a communication beam transition is set to occur at a time point <NUM> between the third symbol (symbol <NUM>) <NUM> and the fourth symbol (symbol <NUM>) <NUM>. The beam switch location <NUM> refers to the point in time where communication of the third symbol <NUM> and communication of the fourth symbol <NUM> will occur on different communication beams. In alternative exemplary embodiments, the beam switch location may occur at points other than a boundary between communication symbols, and may occur anywhere within the communication slot <NUM>.

In accordance with an exemplary embodiment of the disclosure, one or more parameters, aspects, or features of the configuration of the symbol or symbols preceding or following the beam switch location <NUM>, that is the third symbol <NUM> and/or the fourth symbol <NUM>, may be examined and at least partly used to determine the sub-carrier frequency spacing for the symbol or symbols preceding and/or following the beam switch location <NUM>. In an exemplary embodiment, the determination of whether to adjust the sub-carrier frequency spacing for a symbol may be made prior to the transmission. For example, one or more communication parameters may be configured soon after a UE is accessed into a communication network at which time the UE can identify such parameters and determine whether to adjust sub-carrier frequency spacing before any subsequent transmission. Other paramemters can be dynamically configured, e.g. by an RRC communication or a downlink control information (DCI) communication; however, the configuration is completed and the UE is notified of the configuration prior to the transmission.

In accordance with an exemplary embodiment of the disclosure, in the example where the beam switch location <NUM> is at the boundary between the third symbol <NUM> and the fourth symbol <NUM>, one or more parameters, aspects, or features of the configuration of the third symbol <NUM> and/or the fourth symbol <NUM>, may be examined and at least partly used to determine the sub-carrier spacing used to transmit the third symbol <NUM> and/or the fourth symbol <NUM>. For example, the term "one or more parameters, aspects, or features of the configuration" of a communication symbol may refer to the contents, priority, or other features of the communication symbol. For example, a communication symbol carrying a demodulation reference signal (DMRS), channel state information-reference signal (CSI-RS), and a communication having a modulation and coding scheme (MCS) having a high reliability requirement may be considered a high priority symbol that may warrant altering (that is, reducing) the sub-carrier frequency spacing to create a symbol having a longer guard period at the beginning of the communication symbol for those selected symbols. Other examples of "one or more parameters, aspects, or features of the configuration" of a communication symbol can include the CP length of a symbol in the TTI, the channel delay estimation, and the capability of a communication device to complete a beam switch (e.g., the beam switch delay, which can be described as the duration of time that the beam switch will take to settle to a stable state on a target communication beam from the time at which the beam switch is initiated, also referred to as the triggering time). An example of this situation is when the CP length of a symbol occurring after the beam transition time is likely to be smaller than the sum of the length of the channel delay and the beam switch delay time. In such a situation, it may be beneficial to alter the sub-carrier frequency spacing of the symbol following the beam transition time to have a longer guard period to protect the payload from the possibility of ISI. Regarding the use of "one or more parameters, aspects, or features of the configuration" of a communication symbol occurring before the beam switch location <NUM> (i.e., symbol <NUM>, <NUM> in the example of <FIG>), an example of such may be if the symbol <NUM> is of a lower priority (for example, a gap symbol) or if the symbol <NUM> has a lower required EVM to decode (e.g., a PDCCH symbol which uses a lower modulation order and channel coding with lower coding rate), then the beam switch time may occur earlier than the beam switch location <NUM>, in order to further protect the high priority symbol <NUM> from ISI. In this manner, instead of just adjusting the sub-carrier frequency spacing of the symbol <NUM>, additional guard period time may be provided for the symbol <NUM> by making the beam transition time earlier than the time <NUM>.

Moreover, the point in time of the beam switch location can be flexible, and in alternative embodiments, can be based on the implementation of a base station and/or a UE. For example, if the third symbol <NUM> is a gap symbol having no information, both the base station and the UE can transition from a serving beam to a target beam prior to the beam switch location <NUM>, to prepare for the fourth communication symbol <NUM>, which may be a high priority symbol. In other words, the beam switch may occur at a time other than the boundary between communication symbols in some instances.

As an example, the definition of the communication symbol "before" and the communication symbol "after" the beam switch location may be as follows. The communication symbol immediately before the beam switch location could be the last communication symbol having a first sample of payload (not including those samples that are part of the CP) that is sent before the beam switch location. The communication symbol immediately after the beam switch location could be the first communication symbol having a first sample of payload (not including those samples that are part of the CP) that is sent after the beam switch location. Therefore, the beam switch location may occur anywhere within a communication symbol.

<FIG> is a diagram <NUM> showing two communication symbols at a sub-carrier spacing of <NUM>. The vertical axis represent frequency (f) and the horizontal axis represents time (t). The diagram <NUM> shows a first communication symbol <NUM> and a second communication symbol <NUM>. The first communication symbol <NUM> includes a CP portion <NUM> and a payload portion <NUM>. The first communication symbol <NUM> comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, occupying a total frequency bandwidth <NUM>. The first communication symbol <NUM> begins at a symbol boundary <NUM> and extends in time to the right.

The second communication symbol <NUM> includes a CP portion <NUM> and a payload portion <NUM>. The second communication symbol <NUM> also comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, and also occupies the total frequency bandwidth <NUM>.

<FIG> is a diagram <NUM> showing a communication symbol at a sub-carrier frequency spacing of <NUM>. The vertical axis represent frequency (f) and the horizontal axis represents time (t). The diagram <NUM> shows a communication symbol <NUM>. The communication symbol <NUM> includes guard period <NUM>, which may comprise a CP portion <NUM>. The communication symbol <NUM> also includes a payload portion <NUM>. The communication symbol <NUM> comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, occupying a total frequency bandwidth <NUM>. The communication symbol <NUM> begins at the symbol boundary <NUM> and extends in time to the right. The first communication symbol <NUM> and the second communication symbol <NUM> of <FIG> have a length that is equal to the length of the communication symbol <NUM> of <FIG>.

In an exemplary embodiment, the communication symbol <NUM> can be configured to carry the same information payload as the communication symbols <NUM> and <NUM> of <FIG>, but can include an extended guard period <NUM>. The communication symbol <NUM> occupies the same time duration, t1, as does the first and second communication symbols <NUM> and <NUM> of <FIG>, and also occupies the same total frequency bandwidth as the communication symbols <NUM> and <NUM>, that is, the total frequency bandwidth <NUM> is the same as the total frequency bandwidth <NUM>. The extended guard period <NUM> is longer than the CP period <NUM> or the CP period <NUM> of <FIG> and may provide a longer period of time for communication beam transition and CP information than either the CP period <NUM> or the CP period <NUM> of <FIG>.

<FIG> is a diagram <NUM> showing two communication symbols at a sub-carrier frequency spacing of <NUM>. The vertical axis represent frequency (f) and the horizontal axis represents time (t). The diagram <NUM> shows a first communication symbol <NUM> and a second communication symbol <NUM>. The first communication symbol <NUM> includes a CP portion <NUM> and a payload portion <NUM>. The first communication symbol <NUM> comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, occupying a total frequency bandwidth <NUM>. The first communication symbol <NUM> begins at a symbol boundary <NUM> and extends in time to the right. In an exemplary embodiment, the first communication symbol <NUM> has a payload portion <NUM> that carries a demodulation reference signal (DMRS) in sub-carrier <NUM>, and a zero power demodulation reference signal (ZP DMRS) in sub-carrier <NUM>. The first communication symbol <NUM> also carries DMRS and ZP DMRS in the other unnumbered sub-carriers of the payload portion <NUM> as shown in <FIG>.

The second communication symbol <NUM> includes a CP portion <NUM> and a payload portion <NUM>. The second communication symbol <NUM> also comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, and also occupies the total frequency bandwidth <NUM>. The second communication symbol <NUM> has a payload portion <NUM> that carries a physical downlink shared channel (PDSCH) in sub-carrier <NUM>. The second communication symbol <NUM> also carries PDSCH in the other unnumbered sub-carriers of the payload portion <NUM> as shown in <FIG>.

<FIG> is a diagram <NUM> showing a communication symbol at a sub-carrier frequency spacing of <NUM>. The vertical axis represent frequency (f) and the horizontal axis represents time (t). The diagram <NUM> shows a communication symbol <NUM>. The communication symbol <NUM> includes guard period <NUM>, which may comprise a CP portion <NUM>. The communication symbol <NUM> also includes a payload portion <NUM>.

The communication symbol <NUM> comprises a number of different sub-carriers <NUM> having a sub-carrier frequency spacing of <NUM>, also called <NUM>/tone, occupying a total frequency bandwidth <NUM>. The communication symbol <NUM> begins at the symbol boundary <NUM> and extends in time to the right. In this example, the <NUM> sub-carriers <NUM> in the payload portion <NUM> comprise a resource block.

The communication symbol <NUM> can be configured to carry the same information as the communication symbols <NUM> and <NUM> of <FIG>, but can include an extended guard period <NUM>. The communication symbol <NUM> occupies the same time duration, t1, as does the first and second communication symbols <NUM> and <NUM> of <FIG>, and also occupies the same total frequency bandwidth as the communication symbols <NUM> and <NUM>, that is, the total frequency bandwidth <NUM> is the same as the total frequency bandwidth <NUM>. The extended guard period <NUM> is longer than the CP period <NUM> or the CP period <NUM> and may provide a longer period of time for communication beam transition and CP information than either the CP period <NUM> or the CP period <NUM> of <FIG>.

In an exemplary embodiment, the configuration of the communication symbol <NUM> may be sent from a base station (gNB) to a UE in a signaling communication using one or more of a downlink control information (DCI) communication, a radio resource control (RRC) communication, a medium access control-control element (MAC-CE) communication, or another signaling communication.

In an exemplary embodiment, the communication symbol <NUM> has a payload portion <NUM> that carries a demodulation reference signal (DMRS) in sub-carrier <NUM>, a PDSCH in sub-carrier <NUM>, a zero power demodulation reference signal (ZP DMRS) in sub-carrier <NUM> and a PDSCH in sub-carrier <NUM>. In accordance with an exemplary embodiment of the disclosure, the DMRS in sub-carrier <NUM>, the ZP DMRS in sub-carrier <NUM>, and the PDSCH in sub-carrier <NUM> of the first and second communication symbols <NUM> and <NUM> in <FIG>, are interleaved, or otherwise included in sub-carriers <NUM>, <NUM>, <NUM> and <NUM> of communication symbol <NUM>, such that the total frequency bandwidth of <NUM>, in this example, occupied by the DMRS in sub-carrier <NUM>, the ZP DMRS in sub-carrier <NUM>, and the PDSCH in sub-carrier <NUM>, at <NUM> sub-carrier frequency spacing as shown in <FIG>, is the same as the total frequency bandwidth of <NUM>, in this example, occupied by the DMRS in sub-carrier <NUM>, the PDSCH in sub-carrier <NUM>, the ZP DMRS in sub-carrier <NUM> and the PDSCH in sub-carrier <NUM> at <NUM> sub-carrier frequency spacing as shown in <FIG>. The payload of <NUM> and payload of <NUM> of the communication symbols <NUM> and <NUM> are frequency division multiplexed in the communication symbol <NUM> in such a way that the interval in frequency between neighboring DMRS tones (sub-carriers) in communication symbol <NUM> is maintained with respect to the frequency between neighboring DMRS tones in the communication symbol <NUM> in <FIG>. Therefore, channel estimation using the DMRS symbols before adjusting sub-carrier frequency spacing (<FIG>) and after adjusting sub-carrier frequency spacing (<FIG>) is expected to have the same resolution in the frequency domain. In an exemplary embodiment, the communication symbol <NUM> may be referred to as a combined communication symbol in that it can be configured to include the information in the communication symbols <NUM> and <NUM> of <FIG>. In an exemplary embodiment, the payload <NUM> of the combined communication symbol <NUM> is configured such that a minimum frequency interval between two sub-carriers that contain the payload of the pre-combined communication symbols <NUM> and <NUM> is maintained in the payload portion <NUM> of the combined communication symbol <NUM>. Therefore, the same level of frequency diversity is expected from the PDSCH symbols before adjusting sub-carrier frequency spacing (<FIG>) and after adjusting sub-carrier frequency spacing (<FIG>) so that the same resolution in the frequency domain is maintained between the payload <NUM> and <NUM> of <FIG> and the payload <NUM> of <FIG>.

In an exemplary embodiment, the communication symbol <NUM> may be referred to as a first pre-combined communication symbol and the communication symbol <NUM> may be referred to as a second pre-combined communication symbol. The communication symbol <NUM> and the communication symbol <NUM> may be combined to form the combined communication symbol <NUM>. In an exemplary embodiment of a nonlimiting example, in the payload <NUM> of the combined communication symbol <NUM>, all even sub-carrier frequencies (such as the frequencies associated with the DMRS and ZP DMRS communications) may contain the payload <NUM> from the first pre-combined communication symbol <NUM>, and all odd sub-carrier frequencies (such as the frequencies associated with the PDSCH communication) may contain the payload <NUM> from the second pre-combined communication symbol <NUM>. The DMRS, PDSCH and ZP DMRS are also carried in the other unnumbered sub-carriers of the payload portion <NUM> as shown in <FIG>.

<FIG> is a diagram <NUM> showing a communication symbol including a CP period in which a beam switch may occur. The communication symbol <NUM> includes a CP portion <NUM> and a payload portion <NUM>. A beam switch time period is shown at <NUM>, beginning with a beam switch command at a time, t2, and a beam switch completion at a time t3. The time between t2 and t3 may also be referred to as a beam switch time, or beam transition time. If the beam switch time <NUM> extends beyond the CP portion <NUM>, it may cause additional inter-symbol interference (ISI) leakage into the samples in the payload portion <NUM>. This may cause a loss of the circulant property in the CP-OFDM channel matrix (similar to ISI) due to channel delay taps being longer than the CP) and may cause error vector magnitude (EVM) loss and lower decoding rates. The effect of beam switching may be different for different types of symbols. If this leakage of the ISI beyond the CP portion <NUM> into the payload portion <NUM> occurs on a high priority symbol, such as a DMRS, the channel estimation may be corrupted, and the error may propagate to additional symbols.

<FIG> is a diagram <NUM> illustrating a communication symbol having a weighted overlap and add (WOLA) portion. The communication symbol includes an example of a head tone sub-symbol <NUM> and a complex-valued sub-symbol weighting function comprising a real part <NUM> and an imaginary part <NUM>. The extension (EXT) of sub-symbol <NUM> may have a duration or length of L<NUM>. The sub-symbol weighting function may be applied during a time interval <NUM> (OFDM waveform length + extension length L<NUM>) by, for example, the weighting function <NUM> (<FIG>). Note that the extension of length L<NUM> extends a duration or time interval L<NUM>/<NUM> from the sub-symbol head and L<NUM>/<NUM> from the sub-symbol tail. That is, in <FIG>, the notation "EXT" represents a time interval of one-half the extension. The notation "CP" denotes the cyclic prefix. The EXT time interval may be used for an overlap and add portion of a WOLA operation.

<FIG> is a diagram <NUM> illustrating an example of an extended guard period associated with communication symbols in accordance with various aspects of the present disclosure. The tail portion of a first symbol <NUM> is overlapped with the head portion of a second symbol <NUM> that immediately follows first symbol <NUM> in time. The duration or length of the overlap interval <NUM> may be referred to as L<NUM>.

In an exemplary embodiment, an extended guard period <NUM> may be created by adjusting the sub-carrier frequency spacing for the second symbol <NUM> to a sub-carrier frequency spacing that is narrower, or smaller, than the sub-carrier frequency spacing of the first symbol <NUM>. For example, the first symbol <NUM> may have a sub-carrier frequency spacing of <NUM> and the second symbol <NUM> may have a sub-carrier frequency spacing of <NUM>. In an exemplary embodiment, a first communication beam <NUM>, which may be referred to as a serving beam, may be used for transmission of the first symbol <NUM>, while a second communication beam <NUM>, which may be referred to as a target beam, may be used for transmission of the second symbol <NUM>. In an exemplary embodiment, the communication beam switch from the first communication beam <NUM> to the second communication beam <NUM> may be configured to occur during the extended guard period <NUM>.

The extended guard period <NUM> may comprise a WOLA window <NUM> during which the above-described WOLA function may occur. The extended guard period <NUM> may also comprise a CP period <NUM>. The extended guard period <NUM> includes a time, t2, <NUM> at which a beam switch command may be initiated to begin the beam transition, and a time, t3, <NUM> by which the beam transition may be completed. The extended guard period <NUM> may also optionally include a time period <NUM> during which both the first communication beam <NUM> and the second communication beam <NUM> may be muted. In an exemplary embodiment, the time period <NUM> may occur between the time t2, <NUM> and the time t3, <NUM>. The time period <NUM> may comprise a time period during which both the serving beam <NUM> and the target beam <NUM> are optionally muted, and in an exemplary embodiment, may also be shorter than the time between time t2, <NUM> and time t3, <NUM>. In an exemplary embodiment, the time t2, <NUM> should occur after the completion time of the WOLA window <NUM>. Further, at any point during the beam switching time (i.e., between the time t2, <NUM> and the time t3, <NUM>), both the serving beam <NUM> and the target beam <NUM> may optionally be muted. In an exemplary embodiment, muting one or more of the serving beam <NUM> and the target beam <NUM> can reduce transmission power consumption, and may reduce possible inter-symbol-interference that may affect subsequent transmissions, and may reduce cochannel interference to other communication links, as the samples that would be sent/ received during the muting time will not be used for decoding. The extended guard period <NUM> may be sufficiently long to allow completion of the beam switch (shown being completed at time, t3, <NUM>) and the inclusion of a CP <NUM> prior to the beginning of the payload period <NUM>.

<FIG> is a drawing <NUM> showing an example of an OFDM symbol having an extended guard period, within which a beam transition occurs and within which a CP may be applied to a communication symbol in accordance with various aspects of the present disclosure. The communication symbol <NUM> includes an extended guard period <NUM>, which may include a beam switch time period <NUM> and a CP portion <NUM>. A payload portion <NUM> follows the CP portion <NUM>.

The beam switch time period <NUM> begins with a beam switch command at a time, t2, and ends at a beam switch completion at a time t3. The time between t2 and t3 may also be referred to as a beam switch time. The extended guard period <NUM> allows the beam switch time period <NUM> to occur and complete, and then also allows a CP to be applied to the symbol <NUM> prior to the beginning of the payload period <NUM>. In this manner, the extended guard period <NUM> includes sufficiednt time for a beam transition to complete and also allows for time for a CP to be applied prior to the beginning of the payload portion <NUM>, while minimizing the possibility of any additional ISI that may result were the beam switch time to extend into the payload period <NUM>.

<FIG> is a flow chart illustrating an example of a method <NUM> for communication in accordance with various aspects of the present disclosure. The blocks in the method <NUM> may occur in the order shown, or may occur at least partly in parallel.

In block <NUM>, optionally, a communication device, such as a base station (gNB), may receive a signaling from another communication device, such as a UE, indicating the other communication device's capability to complete a communication beam transition in a specified period of time. The block <NUM> is shown in dotted line in <FIG> to indicate that it is optional.

In block <NUM>, a location in time in a communication transmission time interval where a communication beam transition will occur is identified.

In block <NUM>, a configuration of a communication symbol is determined at least partly based on the identified beam transition location and a priority of the communication symbol, where in the configuration an extended guard period is created by changing the sub-carrier frequency spacing of at least one of the communication symbols following and/or preceding the beam transition location. In an exemplary embodiment, the determination of the symbol configuration may be at least in part based on the signaling received in optional block <NUM>.

In block <NUM>, the configuration of the communication symbol is sent in a signaling communication to a second communication device.

In block <NUM>, optionally, a communication device, such as a UE, may report a communicaton beam transition completion time capability to another communication device, such as to a base staion (gNB). The block <NUM> is shown in dotted line in <FIG> to indicate that it is optional.

In block <NUM>, a UE may receive a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI).

In block <NUM>, a UE may identify the beam transition location at least in part based on the received signal in the TTI.

In block <NUM>, a UE may determine a configuration of a communication symbol at least partly based on the received signaling and/or a predefined method, where in the configuration an extended guard period is created by changing the sub-carrier frequency spacing of at least one of the symbols following and/or preceding the identified beam transition location, so that the sub-carrier frequency spacing for the symbol immediately following and/or preceding the beam transition location is different than the sub-carrier frequency spacing for a symbol that does not immediately precede and/or follow the beam transition location. In an exemplary embodiment, the communication configuration in block <NUM> and/or the configuration determined in block <NUM> may be at least partly determined by the capability reported in optional block <NUM>.

<FIG> is a functional block diagram illustrating an apparatus <NUM> for adjusting sub-carrier frequency spacing in accordance with various aspects of the present disclosure. The apparatus <NUM> comprises optional means <NUM> for receiving a signaling from another communication device, such as a UE, indicating the other communication device's capability to complete a communication beam transition in a specified period of time. In certain embodiments, the optional means <NUM> for receiving a signaling from another communication device can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the optional means <NUM> for receiving a signaling from another communication device may comprise a base station (gNB) <NUM> (<FIG>) receiving a signaling communication from a UE <NUM> (<FIG>) indicating the UE's capability to complete a communication beam transition in a specified period of time. The means <NUM> is shown in dotted line in <FIG> to indicate that it is optional.

The apparatus <NUM> further comprises means <NUM> for identifying a location in time in a communication transmission time interval where a communication beam transition will occur. In certain embodiments, the means <NUM> for identifying a location in time in a communication transmission time interval where a communication beam transition will occur can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for identifying a location in time in a communication transmission time interval where a communication beam transition will occur may comprise a base station (gNB) <NUM> (<FIG>) identifying a communication beam transition time and/or location.

The apparatus <NUM> further comprises means <NUM> for determining a configuration of a communication symbol at least partly based on the identified beam transition location and a priority of the communication symbol, where in the configuration an extended guard period is created by changing the sub-carrier frequency spacing of at least one of the communication symbols following and/or preceding the beam transition location. In certain embodiments, the means <NUM> for determining a configuration of a communication symbol can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for determining a configuration of a communication symbol may comprise the base station (gNB) <NUM> (<FIG>) determining whether to adjust sub-carrier frequency spacing of one or more communication symbols following and/or preceding the beam transition time.

The apparatus <NUM> further comprises means <NUM> for sending the configuration of the communication symbol in a signaling communication to a second communication device. In certain embodiments, the means <NUM> for sending the configuration of the communication symbol in a signaling communication to a second communication device can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for sending the configuration of the communication symbol in a signaling communication to a second communication device may comprise the base station (gNB) <NUM> (<FIG>) sending the configuration of the communication symbol in a signaling to a UE <NUM> (<FIG>).

<FIG> is a functional block diagram illustrating an apparatus <NUM> for adjusting sub-carrier frequency spacing in accordance with various aspects of the present disclosure. The apparatus <NUM> comprises optional means <NUM> for reporting a communicaton beam transition completion time capability to another communication device. In certain embodiments, the optional means <NUM> for reporting a communicaton beam transition completion time capability to another communication device can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the optional means <NUM> for reporting a communicaton beam transition completion time capability to another communication device may comprise a UE (<FIG>) reporting its capability to complete a communication beam transition in a specified period of time to a base station (gNB) <NUM> (<FIG>). The means <NUM> is shown in dotted line in <FIG> to indicate that it is optional.

The apparatus <NUM> comprises means <NUM> for receiving a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI). In certain embodiments, the means <NUM> for receiving a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI) can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for receiving a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI) may comprise a UE <NUM> (<FIG>) receiving a signaling indicating one or more of a beam transition location and/or a communication configuration for a transmission time interval (TTI) from a base station (gNB) <NUM> (<FIG>).

The apparatus <NUM> further comprises means <NUM> for identifying the beam transition location at least in part based on the received signal in the TI. In certain embodiments, the means <NUM> for identifying the beam transition location at least in part based on the received signal in the TI can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for identifying the beam transition location at least in part based on the received signal in the TI may comprise a UE <NUM> (<FIG>) identifying the beam transition location.

The apparatus <NUM> further comprises means <NUM> for determining a configuration of a communication symbol at least partly based on the received signaling and/or a predefined method, where in the configuration an extended guard period is created by changing the sub-carrier frequency spacing of at least one of the symbols following and/or preceding the identified beam transition location, so that the sub-carrier frequency spacing for the symbol immediately following and/or preceding the beam transition location is different than the sub-carrier frequency spacing for a symbol that does not immediately precede and/or follow the beam transition location. In certain embodiments, the means <NUM> for determining a configuration of a communication symbol can be configured to perform one or more of the function described in operation block <NUM> of method <NUM> (<FIG>). In an exemplary embodiment, the means <NUM> for determining a configuration of a communication symbol may comprise a UE <NUM> (<FIG>) determining a configuration of a communication symbol.

Techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. IS-<NUM> Releases <NUM> and A are commonly referred to as CDMA2000 1x, 1x, etc. IS-<NUM> (TIA-<NUM>) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM. , etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over an unlicensed and/or shared bandwidth. The description above, however, describes an LTE/LTE-A system for purposes of example, and LTE terminology is used in much of the description above, although the techniques are applicable beyond LTE/LTE-A applications.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

The detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The terms "example" and "exemplary," when used in this description, mean "serving as an example, instance, or illustration," and do not mean "preferred" or "advantageous over other examples.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

Non-transitory computer-readable media include both computer storage media and communication media including any non-transitory medium that facilitates transfer of a computer program from one place to another. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. "Disk" and "disc," as used may be herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of non-transitory computer-readable media.

Claim 1:
A method for adjusting communication symbol sub-carrier frequency spacing based on a communication symbol priority at a communication beam transition location, comprising:
identifying (<NUM>) a communication beam transition location in time in a communication transmission time interval, TTI, where a communication beam transition will occur; and
determining (<NUM>) a configuration of a communication symbol that occurs one of immediately following the communication beam transition location and immediately preceding the communication beam transition location, at least partly based on the identified communication beam transition location and an identified high priority of the communication symbol, wherein a communication symbol having at least one of a demodulation reference signal (DMRS), channel state information-reference signal (CSI-RS), and a communication having a modulation and coding scheme (MCS) having a high reliability requirement, is considered a high priority communication symbol, the configuration comprising;
creating an extended guard period by reducing the sub-carrier frequency spacing of one of the communication symbols that occurs one of immediately following the communication beam transition location and immediately preceding the communication beam transition location, so that the sub-carrier frequency spacing for the symbol that occurs one of immediately following the communication beam transition location and immediately preceding the communication beam transition location is different than a sub-carrier frequency spacing for a symbol that does not one of immediately precede the communication beam transition location and immediately follow the communication beam transition location.