Patent Description:
To maintain a radio link between a user equipment (UE) and an access node such as a next Generation NodeB (gNB), beam quality for one or more beam pair links (BPLs) between the UE and the access node (for example, one or more BPLs used for control channel including common control channel and UE specific control channel) should be good enough. Therefore, it is important and necessary to perform beam monitoring or RLM to monitor beam quality for BPLs. <NPL> describes various methods of beam failure detection and recovery request transmission. <NPL> describes various aspects of a beam failure detection and beam recovery mechanism. <NPL> describes methods for beam recovery in the context of radio link failures. <NPL> discloses a discussion on issues associated with enhanced RLM.

An embodiment of the disclosure provides an apparatus for a user equipment (UE) including circuitry configured to: decode a Reference Signal (RS) received from an access node; and determine beam quality for one or more beam pair links (BPLs) of the RS between the UE and the access node based on the decoded RS, wherein each of the BPLs comprises a transmit (Tx) beam of the access node and a receive (Rx) beam of the UE.

Embodiments of the disclosure will be illustrated, by way of example and not limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements.

Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. However, it will be apparent to those skilled in the art that many alternate embodiments may be practiced using portions of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well known features may have been omitted or simplified in order to avoid obscuring the illustrative embodiments.

Further, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the illustrative embodiments; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation.

The phrase "in an embodiment" is used repeatedly herein. The phrase generally does not refer to the same embodiment; however, it may. The terms "comprising," "having," and "including" are synonymous, unless the context dictates otherwise. The phrases "A or B" and "A/B" mean "(A), (B), or (A and B).

In a Multiple-Input and Multiple-Output (MIMO) system operating in high band, hybrid beamforming can be applied. An access node (e. g, a gNB) and a UE may maintain a plurality of beams. There may be multiple BPLs between the access node and the UE, which can provide good beamforming gain. A good BPL can help to increase link budget. Therefore, monitoring beam quality for BPLs is very important.

The present disclosure provides approaches to perform RLM. In accordance with some embodiments of the disclosure, beam quality for one or more BPLs between a UE and an access node may be determined based on a Reference Signal (RS) received from the access node so as to perform RLM. In accordance with some embodiments of the disclosure, when the beam quality for all of the BPLs is not good enough to meet a predetermined or configured threshold requirement, a beam recovery request may be encoded for transmission to the access node, or out-of-synchronization (out-of-sync) may be declared directly. In accordance with some embodiments of the disclosure, if the UE cannot find out a good Rx beam to meet the threshold requirement, out-of-sync may be declared. Radio link failure (RLF) may be triggered if a predetermined or configured number of consecutive out-of-sync are declared.

In accordance with some embodiments of the disclosure, the term "beam" or "beam pail link (BPL)" of a RS discussed herein may refer to an antenna port of the RS.

<FIG> illustrates an architecture of a system <NUM> of a network in accordance with some embodiments. The system <NUM> is shown to include a user equipment (UE) <NUM>. The UE <NUM> is illustrated as a smartphone (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a personal data assistant (PDA), a tablet, a pager, a laptop computer, a desktop computer, a wireless handset, or any computing device including a wireless communications interface.

The UE <NUM> may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) <NUM>, which may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. The UE <NUM> may utilize a connection <NUM> which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connection <NUM> is illustrated as an air interface to enable communicative coupling and may be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a Code-Division Multiple Access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (<NUM>) protocol, a New Radio (NR) protocol, and the like.

The RAN <NUM> may include one or more access nodes (ANs) that enable the connection <NUM>. These access nodes may be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RAN nodes, and so forth, and may include ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). As shown in <FIG>, for example, the RAN <NUM> may include AN <NUM> and AN <NUM>. The AN <NUM> and AN <NUM> may communicate with one another via an X2 interface <NUM>. The AN <NUM> and AN <NUM> may be macro ANs which may provide lager coverage. Alternatively, they may be femtocell ANs or picocell ANs, which may provide smaller coverage areas, smaller user capacity, or higher bandwidth compared to macro ANs. For example, one or both of the AN <NUM> and AN <NUM> may be a low power (LP) AN. In an embodiment, the AN <NUM> and AN <NUM> may be the same type of AN. In another embodiment, they are different types of ANs.

Any of the ANs <NUM> and <NUM> may terminate the air interface protocol and may be the first point of contact for the UE <NUM>. In some embodiments, any of the ANs <NUM> and <NUM> may fulfill various logical functions for the RAN <NUM> including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In accordance with some embodiments, the UE <NUM> may be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with any of the ANs <NUM> and <NUM> or with other UEs (not shown) over a multicarrier communication channel in accordance various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and Proximity-Based Service (ProSe) or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals may include a plurality of orthogonal subcarriers.

In some embodiments, a downlink resource grid may be used for downlink transmissions from any of the ANs <NUM> and <NUM> to the UE <NUM>, while uplink transmissions may utilize similar techniques. The grid may be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot.

The physical downlink shared channel (PDSCH) may carry user data and higher-layer signaling to the UE <NUM>. It may also inform the UE <NUM> about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE <NUM> within a cell) may be performed at any of the ANs <NUM> and <NUM> based on channel quality information fed back from the UE <NUM>. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) the UE <NUM>.

The PDCCH may be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There may be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=<NUM>, <NUM>, <NUM>, or <NUM>).

Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more enhanced control channel elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an enhanced resource element groups (EREGs). An ECCE may have other numbers of EREGs in some situations.

The RAN <NUM> is shown to be communicatively coupled to a core network (CN) <NUM> via an S1 interface <NUM>. In some embodiments, the CN <NUM> may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN. In an embodiment, the S1 interface <NUM> is split into two parts: the S1-mobility management entity (MME) interface <NUM>, which is a signaling interface between the ANs <NUM> and <NUM> and MMEs <NUM>; and the S1-U interface <NUM>, which carries traffic data between the ANs <NUM> and <NUM> and the serving gateway (S-GW) <NUM>.

In an embodiment, the CN <NUM> may comprise the MMEs <NUM>, the S-GW <NUM>, a Packet Data Network (PDN) Gateway (P-GW) <NUM>, and a home subscriber server (HSS) <NUM>.

In addition, the S-GW <NUM> may be a local mobility anchor point for inter-AN handovers and also may provide an anchor for inter-3GPP mobility.

The P-GW <NUM> may terminate a SGi interface toward a PDN. The P-GW <NUM> may route data packets between the CN <NUM> and external networks such as a network including an application server (AS) <NUM> (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface <NUM>. In an embodiment, the P-GW <NUM> is communicatively coupled to an application server <NUM> via an IP communications interface <NUM>. The application server <NUM> may also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UE <NUM> via the CN <NUM>.

The quantity of devices and/or networks illustrated in <FIG> is provided for explanatory purposes only. In practice, there may be additional devices and/or networks, fewer devices and/or networks, different devices and/or networks, or differently arranged devices and/or networks than illustrated in <FIG>. Alternatively or additionally, one or more of the devices of environment <NUM> may perform one or more functions described as being performed by another one or more of the devices of environment <NUM>. Furthermore, while "direct" connections are shown in <FIG>, these connections should be interpreted as logical communication pathways, and in practice, one or more intervening devices (e.g., routers, gateways, modems, switches, hubs, etc.) may be present.

<FIG> shows an example for one or more BPLs between a UE and an access node in accordance with some embodiments of the disclosure. In the example of <FIG>, the AN <NUM> may maintain a plurality of transmit (Tx) beams including a Tx beam <NUM> and a Tx beam <NUM>, and the UE <NUM> may maintain a plurality of receive (Rx) beams including a Rx beam <NUM> and a Rx beam <NUM>. There may be one or more BPLs between the AN <NUM> and UE <NUM>, wherein each of the BPLs may be formed by a Tx beam of the AN <NUM> and a Rx beam of the UE <NUM>. For example, as shown in <FIG>, a BPL <NUM> may be formed by the Tx beam <NUM> of the AN <NUM> and the Rx beam <NUM> of the UE <NUM>, and a BPL <NUM> may be formed by the Tx beam <NUM> of the AN <NUM> and the Rx beam <NUM> of the UE <NUM>.

It should be understood that, the number of Tx beams of the AN <NUM>, Rx beams of the UE <NUM> and/or BPLs between the AN <NUM> and the UE <NUM> illustrated in <FIG> is provided for explanatory purposes only and is not limited herein.

As beam quality for one or more BPLs between the AN <NUM> and the UE <NUM> may be effected by one or more Tx beams of the AN <NUM> forming the BPLs and one or more Rx beams of the UE <NUM> forming the BPLs, there are two possible cases if the beam quality for the BPLs is not good: one is that the Tx beams forming the BPLs are not good, the other is that the Rx beams forming the BPLs are not good. In the former case, in order to improve the beam quality for the BPLs, the best Tx beams of the AN <NUM> may be selected to form the BPLs, or if a better AN (e.g. AN <NUM>) exists (for example, as the UE <NUM> moves away from the AN <NUM> and moves into the coverage area of another AN such as AN <NUM>), the best Tx beams of the better AN may be selected to form the BPLs. In the latter case, namely, if the best Tx beams have already been applied to the BPLs and the Rx beams of the BPLs are not good, the best Rx beams of the UE <NUM> may be selected to form the BPLs so as to improve the beam quality for the BPLs. In the following description, for ease of explanation only, it is assumed that the best Tx beams have already been selected to form the BPLs.

<FIG> is a flow chart showing operations for RLM in accordance with some embodiments of the disclosure. The operations of <FIG> may be used for a UE (e.g. UE <NUM>) to monitor a radio link between the UE and an AN (e.g. AN <NUM>) of a RAN (e.g. RAN <NUM>) based on a RS received from the AN.

At <NUM>, AN <NUM> may process (e.g. modulate, encode, etc.) a RS and transmit the RS to UE <NUM> for RLM. In an embodiment, the RS may be transmitted with a beam sweeping operation. The RS may be a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS), which may be pre-defined or configured by higher layer signaling. In an embodiment, a SS Block (SSB) may include a Primary SS (PSS), a secondary SS (SSS) and a Physical Broadcast Channel (PBCH). In an embodiment, a SSB may also include a Demodulation Reference Signal (DMRS) used for common control channel.

At <NUM>, the UE <NUM> may receive and process (e.g. demodulate, decode, detect, etc.) the RS that the AN <NUM> transmitted at <NUM>, to determine beam quality for one or more beam BPLs of the RS between the UE <NUM> and the AN <NUM> based on the processed RS. The beam quality for the BPLs may be determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the processed RS.

A first threshold may be configured by higher layer signaling for determining whether the UE <NUM> needs to process (e.g. modulate, encode, etc.) a beam recovery request for transmission to the AN <NUM>. In an embodiment, at <NUM>, the UE <NUM> may process (e.g. modulate, encode, etc.) a beam recovery request and transmit the beam recovery request to the AN <NUM> if the beam quality for all of the BPLs is below the first threshold. In another embodiment, at <NUM>, the UE <NUM> may process (e.g. modulate, encode, etc.) a beam recovery request and transmit the beam recovery request to the AN <NUM> if the beam quality for all of the BPLs is below the first threshold for a predetermined or configured time period.

Alternatively, in addition to the first threshold, a second threshold may also be configured by higher layer signaling. In an embodiment, at <NUM>, the UE <NUM> may process (e.g. modulate, encode, etc.) a beam recovery request and transmit the beam recovery request to the AN <NUM> if the beam quality for all of the BPLs is below the first threshold and above the second threshold. In another embodiment, at <NUM>, the UE <NUM> may process (e.g. modulate, encode, etc.) a beam recovery request and transmit the beam recovery request to the AN <NUM> if the beam quality for all of the BPLs is below the first threshold and above the second threshold for a predetermined or configured time period. The beam recovery request may be directed to a predetermined number of BPLs among the BPLs, wherein the predetermined number may be pre-defined or configured by higher layer signaling or may be determined by the beam quality of the BPLs. In yet another embodiment, instead of processing (e.g. modulating, encoding, etc.) a beam recovery request for transmission to the AN <NUM> at <NUM>, the UE <NUM> may directly determine that out-of-sync occurs if the beam quality for all of the BPLs is below the second threshold. In still another embodiment, instead of processing (e.g. modulating, encoding, etc.) a beam recovery request for transmission to the AN <NUM> at <NUM>, the UE <NUM> may directly determine that out-of-sync occurs if the beam quality for all of the BPLs is below the second threshold for a predetermined or configured time period.

It is to be noted that, for the SS and CSI-RS, the thresholds discussed above may be the same or different.

In response to receiving and processing (e.g. demodulating, decoding, detecting, etc.) the beam recovery request that the UE <NUM> transmitted at <NUM>, the AN <NUM> may process (e.g. modulate, encode, etc.) a Channel State Information Reference Signal (CSI-RS) and transmit the CSI-RS to the UE <NUM> for UE beam refinement at <NUM>. The CSI-RS may be transmitted at pre-defined or pre-configured resources. If the beam recovery request is directed to a predetermined number of BPLs among the BPLs, the CSI-RS may be processed (e.g. modulated, encoded, etc.) with the predetermined number of Tx beams in the predetermined number of BPLs.

At <NUM>, the UE <NUM> may receive and process (e.g. demodulate, decode, detect, etc.) the CSI-RS that the AN <NUM> transmitted at <NUM>, to determine beam quality for one or more Rx beams of the UE based on the processed CSI-RS. The beam quality for the Rx beams may be determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the processed CSI-RS. The UE <NUM> may re-process (e.g. re-modulate, re-encode, etc.) the beam recovery request and re-transmit the beam recovery request to the AN <NUM>, if no CSI-RS is received after the beam recovery request is transmitted at <NUM>.

In an embodiment, the UE <NUM> may determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold. In another embodiment, the UE <NUM> may determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold for a predetermined or configured time period. In yet another embodiment, the UE <NUM> may determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold. In still another embodiment, the UE <NUM> may determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold for a predetermined or configured time period.

In addition, in an embodiment, the UE <NUM> may determine that in-synchronization (in-sync) occurs if the beam quality for the Rx beams is above a third threshold. In another embodiment, the UE <NUM> may determine that in-sync occurs if the beam quality for the Rx beams is above a third threshold for a predetermined or configured time period. The third threshold discussed above may be the same as or different from the first threshold.

The UE <NUM> may determine that radio link failure (RLF) occurs if the number of consecutive out-of-sync reaches a predetermined or configured number, wherein the predetermined or configured number may be determined based on capability of Rx beams of the UE.

<FIG> is a flow chart showing a method performed by a UE during RLM in accordance with the claimed invention. The operations of <FIG> may be used for a UE (e.g. UE <NUM>) to monitor a radio link between the UE and an AN (e.g. AN <NUM>) of a RAN (e.g. RAN <NUM>) based on a RS received from the AN.

The method starts at <NUM>. At <NUM>, the UE <NUM> processes (e.g. demodulate, decode, detect, etc.) a RS received from the AN <NUM>. At <NUM>, the UE <NUM> determines beam quality for one or more beam BPLs of the RS between the UE <NUM> and the AN <NUM> based on the processed RS. As discussed hereinbefore, the beam quality for the BPLs may be determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the processed RS.

Then, the UE <NUM> determines whether the beam quality for the BPLs meets a threshold requirement at <NUM>. If yes, the method may return back to <NUM>, and if not, the method may proceed to <NUM>, where the UE <NUM> processes (e.g. modulate, encode, etc.) a beam recovery request for transmission to the AN <NUM>. The threshold requirement may be configured by higher layer signaling, as discussed hereinbefore. In addition, in an embodiment not covered by the claimed invention and although not shown, if the beam quality for the BPLs does not meet a threshold requirement at <NUM>, the method may also proceed to <NUM> directly, namely, the UE <NUM> may directly determine that out-of-sync occurs, rather than processing (e.g. modulating, encoding, etc.) a beam recovery request for transmission to the AN <NUM> at <NUM>.

The UE <NUM> determines at <NUM> that if a Channel State Information Reference Signal (CSI-RS) has been received. If yes, the UE <NUM> processes (e.g. demodulate, decode, detect, etc.) the CSI-RS to determine beam quality for one or more Rx beams of the UE based on the processed CSI-RS at <NUM>, and if not, the method may return back to <NUM>. As discussed hereinbefore, the beam quality for the Rx beams may be determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the processed CSI-RS.

Then, the UE <NUM> determines whether the beam quality for the Rx beams meets the threshold requirement at <NUM>. If yes, the method may return back to <NUM>, and if not, the method may proceed to <NUM>, where the UE <NUM> determines that out-of-sync occurs. The threshold requirement may be configured by higher layer signaling, as discussed hereinbefore. In addition, although not shown, the UE <NUM> may determine that in-sync occurs if the beam quality for the Rx beams meets the threshold requirement at <NUM>.

Then, the UE <NUM> determines whether the number of consecutive out-of-sync reaches a predetermined or configured number at <NUM>. If yes, the UE <NUM> determines that RLF occurs, and if not, the method may return back to <NUM>. The method ends at <NUM>.

<FIG> is a flow chart showing a method performed by an access node during RLM in accordance with some embodiments of the disclosure. The operations of <FIG> may be used for an AN (e.g. AN <NUM>) of a RAN (e.g. RAN <NUM>) to assist a UE (e.g. UE <NUM>) to monitor the radio link between the UE and the AN based on a RS received from the AN. The method starts at <NUM>. At <NUM>, the AN <NUM> may process (e.g. modulate, encode, etc.) a RS and transmit the RS to the UE <NUM> for RLM. As discussed hereinbefore, the RS may be transmitted with a beam sweeping operation. The RS may be a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS), which may be pre-defined or configured by higher layer signaling. In an embodiment, a SS Block (SSB) may include a Primary SS (PSS), a secondary SS (SSS) and a Physical Broadcast Channel (PBCH). In an embodiment, a SSB may also include a Demodulation Reference Signal (DMRS) used for common control channel.

The AN <NUM> may determine at <NUM> that if a beam recovery request has been received. If yes, the AN <NUM> may process (e.g. modulate, encode, etc.) a Channel State Information Reference Signal (CSI-RS) and transmit the CSI-RS to the UE <NUM> for UE beam refinement, and if not, the method may proceed to <NUM>, where the method ends. As discussed hereinbefore, the CSI-RS may be transmitted at pre-defined or pre-configured resources. If the beam recovery request is directed to a predetermined number of BPLs, the CSI-RS may be processed (e.g. modulated, encoded, etc.) with the predetermined number of Tx beams in the predetermined number of BPLs.

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

The baseband circuitry <NUM> may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry <NUM> and to generate baseband signals for a transmit signal path of the RF circuitry <NUM>. Baseband processing circuity <NUM> may interface with the application circuitry <NUM> for generation and processing of the baseband signals and for controlling operations of the RF circuitry <NUM>. For example, in some embodiments, the baseband circuitry <NUM> may include a third generation (<NUM>) baseband processor 604A, a fourth generation (<NUM>) baseband processor 604B, a fifth generation (<NUM>) baseband processor 604C, or other baseband processor(s) 604D for other existing generations, generations in development or to be developed in the future (e.g., second generation (<NUM>), si6h generation (<NUM>), etc.). The baseband circuitry <NUM> (e.g., one or more of baseband processors 604A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry <NUM>. In other embodiments, some or all of the functionality of baseband processors 604A-D may be included in modules stored in the memory <NUM> and executed via a Central Processing Unit (CPU) 604E. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry <NUM> may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry <NUM> may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry <NUM> may include one or more audio digital signal processor(s) (DSP) 604F. The audio DSP(s) 604F may include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry <NUM> and the application circuitry <NUM> may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the receive signal path of the RF circuitry <NUM> may include mixer circuitry 606a, amplifier circuitry 606b and filter circuitry 606c. In some embodiments, the transmit signal path of the RF circuitry <NUM> may include filter circuitry 606c and mixer circuitry 606a. RF circuitry <NUM> may also include synthesizer circuitry 606d for synthesizing a frequency for use by the mixer circuitry 606a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 606a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry <NUM> based on the synthesized frequency provided by synthesizer circuitry 606d. The amplifier circuitry 606b may be configured to amplify the down-converted signals and the filter circuitry 606c may be a lowpass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry <NUM> for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 606a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 606a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 606d to generate RF output signals for the FEM circuitry <NUM>. The baseband signals may be provided by the baseband circuitry <NUM> and may be filtered by filter circuitry 606c.

In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may be configured for super-heterodyne operation.

In some embodiments, the synthesizer circuitry 606d may be a fractional-N synthesizer or a fractional N/N+<NUM> synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 606d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 606d may be configured to synthesize an output frequency for use by the mixer circuitry 606a of the RF circuitry <NUM> based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 606d may be a fractional N/N+<NUM> synthesizer.

Synthesizer circuitry 606d of the RF circuitry <NUM> may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+<NUM> (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 606d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry <NUM> may include an IQ/polar converter.

While <FIG> shows the PMC <NUM> coupled only with the baseband circuitry <NUM>. However, in other embodiments, the PMC <NUM><NUM> may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry <NUM>, RF circuitry <NUM>, or FEM <NUM>.

For example, if the device <NUM> is in an RRC_Connected state, where it is still connected to the AN as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity.

If there is no data traffic activity for an extended period of time, then the device <NUM> may transition off to an RRC_Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device <NUM> goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device <NUM> may not receive data in this state, in order to receive data, it must transition back to RRC_Connected state.

As referred to herein, Layer <NUM> may comprise a radio resource control (RRC) layer. As referred to herein, Layer <NUM> may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, Layer <NUM> may comprise a physical (PHY) layer of a UE/AN.

<FIG> illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry <NUM> of <FIG> may comprise processors 604A-604E and a memory <NUM> utilized by said processors. Each of the processors 604A-604E may include a memory interface, 704A-704E, respectively, to send/receive data to/from the memory <NUM>.

<FIG> is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, <FIG> shows a diagrammatic representation of hardware resources <NUM> including one or more processors (or processor cores) <NUM>, one or more memory/storage devices <NUM>, and one or more communication resources <NUM>, each of which may be communicatively coupled via a bus <NUM>. For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor <NUM> may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources <NUM>.

Instructions <NUM> may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors <NUM> to perform any one or more of the methodologies discussed herein. The instructions <NUM> may reside, completely or partially, within at least one of the processors <NUM> (e.g., within the processor's cache memory), the memory/storage devices <NUM>, or any suitable combination thereof. Furthermore, any portion of the instructions <NUM> may be transferred to the hardware resources <NUM> from any combination of the peripheral devices <NUM> or the databases <NUM>. Accordingly, the memory of processors <NUM>, the memory/storage devices <NUM>, the peripheral devices <NUM>, and the databases <NUM> are examples of computer-readable and machine-readable media.

The following paragraphs describe examples of various embodiments (i.e. examples <NUM>-<NUM>) which do not fall into the scope of the claimed invention. Example <NUM> includes an apparatus for a user equipment (UE), including circuitry configured to: decode a Reference Signal (RS) received from an access node; and determine beam quality for one or more beam pair links (BPLs) of the RS between the UE and the access node based on the decoded RS, wherein each of the BPLs comprises a transmit (Tx) beam of the access node and a receive (Rx) beam of the UE.

Example <NUM> includes the apparatus of Example <NUM>, wherein the RS is a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS), as pre-defined or configured by higher layer signaling.

Example <NUM> includes the apparatus of Example <NUM>, wherein the beam quality for the BPLs is determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the decoded RS.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for all of the BPLs is below a first threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for all of the BPLs is below a first threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to encode a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to encode a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to encode a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold and above a second threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to encode a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold and above a second threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of any of Examples <NUM>-<NUM>, wherein the beam recovery request is for a predetermined number of BPLs among the BPLs, wherein the predetermined number is pre-defined or configured by higher layer signaling or is determined by the beam quality of the BPLs.

Example <NUM> includes the apparatus of any of Examples <NUM>-<NUM>, wherein the circuitry is further configured to: decode Channel State Information Reference Signal (CSI-RS), wherein the CSI-RS is transmitted from the access node in response to the beam recovery request; and determine beam quality for one or more Rx beams of the UE based on the decoded CSI-RS.

Example <NUM> includes the apparatus of Example <NUM>, wherein the beam quality for the Rx beams is determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the decoded CSI-RS.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that in-sync occurs if the beam quality for the Rx beams is equal to or greater than the first threshold.

Example <NUM> includes the apparatus of Example <NUM>, wherein the circuitry is further configured to determine that in-sync occurs if the beam quality for the Rx beams is equal to or greater than the first threshold for a predetermined or configured time period.

Example <NUM> includes the apparatus of Examples <NUM>-<NUM> or <NUM>-<NUM>, wherein the circuitry is further configured to determine that radio link failure (RLF) occurs if the number of consecutive out-of-sync reaches a predetermined or configured number.

Example <NUM> includes the apparatus of Example <NUM>, wherein the predetermined or configured number is determined based on capability of Rx beams of the UE.

Example <NUM> includes the apparatus of any of Examples <NUM>-<NUM>, wherein the circuitry is further configured to re-encode the beam recovery request for transmission to the access node, if no Channel State Information Reference Signal (CSI-RS) is received after transmitting the beam recovery request.

Example <NUM> includes an apparatus for an access node, including circuitry configured to: encode a Reference Signal (RS) for transmission to a user equipment (UE); decode a beam recovery request for one or more beam pair links (BPLs) of the RS between the UE and the access node received from the UE, wherein each of the BPLs comprises a transmit (Tx) beam of the access node and a receive (Rx) beam of the UE; and encode a Channel State Information Reference Signal (CSI-RS) for transmission to the UE in response to decoding the beam recovery request.

Example <NUM> includes the apparatus of Example <NUM>, wherein the RS is a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS).

Example <NUM> includes the apparatus of Example <NUM>, wherein the CSI-RS is transmitted at pre-defined or pre-configured resources.

Example <NUM> includes the apparatus of Example <NUM>, wherein the beam recovery request is for a predetermined number of BPLs among the BPLs.

Example <NUM> includes the apparatus of Example <NUM>, wherein the CSI-RS is encoded with the predetermined number of Tx beams in the predetermined number of BPLs.

Example <NUM> includes a method performed at a user equipment (UE), including: decoding a Reference Signal (RS) received from an access node; and determining beam quality for one or more beam pair links (BPLs) of the RS between the UE and the access node based on the decoded RS, wherein each of the BPLs comprises a transmit (Tx) beam of the access node and a receive (Rx) beam of the UE.

Example <NUM> includes the method of Example <NUM>, wherein the RS is a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS), as pre-defined or configured by higher layer signaling.

Example <NUM> includes the method of Example <NUM>, wherein the beam quality for the BPLs is determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the decoded RS.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for all of the BPLs is below a first threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for all of the BPLs is below a first threshold for a predetermined or configured time period.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes encoding a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes encoding a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold for a predetermined or configured time period.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes encoding a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold and above a second threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes encoding a beam recovery request for transmission to the access node if the beam quality for all of the BPLs is below a first threshold and above a second threshold for a predetermined or configured time period.

Example <NUM> includes the method of any of Examples <NUM>-<NUM>, wherein the beam recovery request is for a predetermined number of BPLs among the BPLs, wherein the predetermined number is pre-defined or configured by higher layer signaling or is determined by the beam quality of the BPLs.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes: decoding Channel State Information Reference Signal (CSI-RS), wherein the CSI-RS is transmitted from the access node in response to the beam recovery request; and determining beam quality for one or more Rx beams of the UE based on the decoded CSI-RS.

Example <NUM> includes the method of Example <NUM>, wherein the beam quality for the Rx beams is determined by measuring Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ) of the decoded CSI-RS.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold for a predetermined or configured time period.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that out-of-sync occurs if the beam quality for the Rx beams is below the first threshold and above the second threshold for a predetermined or configured time period.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that in-sync occurs if the beam quality for the Rx beams is equal to or greater than the first threshold.

Example <NUM> includes the method of Example <NUM>, wherein the method further includes determining that in-sync occurs if the beam quality for the Rx beams is equal to or greater than the first threshold for a predetermined or configured time period.

Example <NUM> includes the method of Examples <NUM>-<NUM> or <NUM>-<NUM>, wherein the method further includes determining that radio link failure (RLF) occurs if the number of consecutive out-of-sync reaches a predetermined or configured number.

Example <NUM> includes the method of Example <NUM>, wherein the predetermined or configured number is determined based on capability of Rx beams of the UE.

Example <NUM> includes the method of any of Examples <NUM>-<NUM>, wherein the method further includes re-encoding the beam recovery request for transmission to the access node, if no Channel State Information Reference Signal (CSI-RS) is received after transmitting the beam recovery request.

Example <NUM> includes a method performed by an access node, including: encoding a Reference Signal (RS) for transmission to a user equipment (UE); decoding a beam recovery request for one or more beam pair links (BPLs) of the RS between the UE and the access node received from the UE, wherein each of the BPLs comprises a transmit (Tx) beam of the access node and a receive (Rx) beam of the UE; and encoding a Channel State Information Reference Signal (CSI-RS) for transmission to the UE in response to decoding the beam recovery request.

Example <NUM> includes the method of Example <NUM>, wherein the RS is a Synchronization Signal (SS) or a Channel State Information Reference Signal (CSI-RS).

Example <NUM> includes the method of Example <NUM>, wherein the CSI-RS is transmitted at pre-defined or pre-configured resources.

Example <NUM> includes the method of Example <NUM>, wherein the beam recovery request is for a predetermined number of BPLs among the BPLs.

Example <NUM> includes the method of Example <NUM>, wherein the CSI-RS is encoded with the predetermined number of Tx beams in the predetermined number of BPLs.

Example <NUM> includes a non-transitory computer-readable medium having instructions stored thereon, the instructions when executed by one or more processor(s) causing the processor(s) to perform the method of any of Examples <NUM>-<NUM>.

Example <NUM> includes an apparatus for a user equipment (UE), including means for performing the actions of the method of any of Examples <NUM>-<NUM>.

Example <NUM> includes an apparatus for an access node (AN), including means for performing the actions of the method of any of Examples <NUM>-<NUM>.

Example <NUM> includes a user equipment (UE) as shown and described in the description.

Example <NUM> includes an access node (AN) as shown and described in the description.

Example <NUM> includes a method performed at a user equipment (UE) as shown and described in the description.

Example <NUM> includes a method performed at an access node (AN) as shown and described in the description.

Claim 1:
One or more non-transitory, computer-readable media having instructions that, when executed by one or more processors, cause a user equipment, UE, to:
determine one or more beam pair links, BPLs (<NUM>, <NUM>), wherein respective ones of the BPLs (<NUM>, <NUM>) include a transmit, Tx, beam (<NUM>, <NUM>) of an access node and a receive, Rx, beam (<NUM>, <NUM>) of the UE;
decode a Reference Signal, RS, received from the access node, the reference signal related to radio link monitoring, RLM;
determine, at least partially based on the RS, beam quality for the one or more BPLs (<NUM>, <NUM>);
determine that the beam quality for the one or more BPLs (<NUM>, <NUM>) is below a first threshold;
in response to determining that the beam quality for the one or more BPLs (<NUM>, <NUM>) is below the first threshold, encode a beam recovery request for transmission to the access node;
decode a Channel State Information Reference Signal, CSI-RS, received from the access node in response to transmitting the beam recovery request;
determine, at least partially based on the CSI-RS beam quality for one or more Rx beams;
determine that the beam quality for the one or more Rx beams is below the first threshold;
in response to determining that the beam quality for the one or more Rx beams is below the first threshold, identify an occurrence of out-of-sync;
determine that a number of consecutive out-of-syncs has reached a predetermined or configured number; and
in response to determining that the number of consecutive out-of-syncs has reached the predetermined or configured number, determine occurrence of radio link failure, RLF.