Patent Description:
In wireless networks, a cell may be identified by a physical cell identifier (PCI). The PCI may be carried in a primary synchronization signal (PSS) and secondary synchronization signal (SSS) of a synchronization signal block (SSB). In addition, the PCI may be used to determine scrambling sequences of various physical signals or channels, such as the physical broadcast channel (PBCH), physical downlink control channel (PDCCH) CoreSeto, and cell-specific physical downlink shared channel (PDSCH) transmissions.

In some networks, two neighboring cells may be assigned the same PCI, which may result in a PCI collision. For example, in Integrated-Access-Backhaul (IAB) networks that utilize wireless spectrum for both access links (links to user equipment (UEs)) and backhaul links (links to the core network), neighboring IAB nodes (e.g., base stations) may be assigned the same PCI as a result of mobile IAB nodes or zero-network planning. When two neighboring cells have the same PCI, a UE may not be able to differentiate reference signals from each of the neighboring cells. In addition, a PCI collision between two neighboring cells may lead to timing synchronization and channel estimation issues at the UE, and may further result in decoding failure of user data traffic transmitted from one of the two neighboring cells.

<CIT> discloses a relay station relaying wireless signals between a base station and a mobile station, the relay station including: a communication unit configured to relay the wireless signals; a determination unit configured to determine whether or not it is necessary to change a cell ID of the relay station in order to avoid a collision between a cell ID of the relay station and a cell ID of the base station due to a movement of the relay station; and a control unit configured to cause a cell ID of an access point of the mobile station belonging to the relay station to be changed from a first cell ID of the relay station to a second cell ID of the relay station when the determination unit determines that it is necessary to change the cell ID.

<CIT> discloses a method for a cellular telecommunications network including performing a modulo operation on a physical cell identifier (PCI) of a target cell to determine a first PCI mod value, determining first tier neighbors of the target cell, determining that at least one of the first tier neighbors uses a PCI that has a PCI mod value that is the same as the first PCI mod value, comparing a number of handover attempts between the target cell and the at least one first tier neighbor with the first PCI mod value to a first threshold value, and when the number of handover attempts exceeds the threshold value, replacing the PCI of the target cell with a PCI with a second PCI mod value different from the first PCI mod value.

The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a form as a prelude to the more detailed description that is presented later.

Various aspects of the present disclosure relate to facilitating a PCI change within a wireless network based on a primary synchronization signal (PSS) waveform. A scheduling entity, such as a base station or IAB node, communicates with a set of one or more scheduled entities, such as UEs or other IAB nodes, utilizing a first PCI. The scheduling entity then changes from the first PCI to a second PCI, where the second PCI corresponds to a different PSS waveform than the first PCI. The scheduling entity changes the PCI as a result of a PCI collision, as claimed, and/or PSS collision with a neighboring scheduling entity.

In some examples, the scheduling entity may autonomously initiate the PCI change upon discovering a PCI and/or PSS collision with a neighboring scheduling entity. In other examples, the scheduling entity may receive a message from a network node indicating the scheduling entity should perform the PCI change upon the network node discovering a PCI and/or PSS collision with the neighboring scheduling entity. For example, the network node may include a centralized network node, such as another IAB node or other central network entity.

In one example, claimed, a method of wireless communication at a first scheduling entity is disclosed. The method includes communicating with a set of one or more scheduled entities utilizing a first physical cell identifier (PCI), wherein the first PCI corresponds to a first primary synchronisation signal, PSS, waveform; detecting a collision between the first PSS waveform and a third PSS waveform transmitted by a second scheduling entity located proximate to the first scheduling entity; selecting a second PCI, wherein the second PCI corresponds to a second PSS waveform different than the first PSS waveform, to avoid colliding with the third PSS waveform, wherein the first PSS waveform and the third PSS waveform are identical; and changing from the first PCI to a second PCI to communicate with the set of one or more scheduled entities.

Another example, in agreement with the claimed subject matter, provides a first scheduling entity within a wireless communication network including a transceiver configured to communicate with a set of one or more scheduled entities in the wireless communication network, a memory, and a processor communicatively coupled to the transceiver and the memory. The processor and the memory can be configured to communicate with the set of one or more scheduled entities utilizing a first physical cell identifier (PCI), wherein the first PCI corresponds to a first primary synchronisation signal, PSS, waveform; detecting a collision between the first PSS waveform and a third PSS waveform transmitted by a second scheduling entity located proximate to the first scheduling entity; selecting a second PCI, wherein the second PCI corresponds to a second PSS waveform different than the first PSS waveform, to avoid colliding with the third PSS waveform, wherein the first PSS waveform and the third PSS waveform are identical; and change from the first PCI to a second PCI to communicate with the set of one or more scheduled entities.

In another example, claimed, a method of wireless communication at a centralized network node is disclosed. The method includes detecting a collision between a first primary synchronization signal (PSS) waveform corresponding to a first physical cell identifier (PCI) assigned to a first scheduling entity and a second PSS waveform corresponding to a second PCI assigned to a second scheduling entity located proximate to the first scheduling entity. The method further includes selecting a third PCI for the first scheduling entity. The third PCI corresponds to a third PSS waveform different than the first PSS waveform to avoid colliding with the second PSS waveform. The method further includes transmitting a PCI change indication including the third PCI to the first scheduling entity to initiate a change from the first PCI to the third PCI within the first scheduling entity. The first PSS waveform and the second PSS waveform are identical.

Another example, in agreement with the claimed subject matter, provides a centralized network node within a wireless communication network including a transceiver, a memory, and a processor communicatively coupled to the transceiver and the memory. The processor and the memory can be configured to detect a collision between a first primary synchronization signal (PSS) waveform corresponding to a first physical cell identifier (PCI) assigned to a first scheduling entity and a second PSS waveform corresponding to a second PCI assigned to a second scheduling entity located proximate to the first scheduling entity. The processor and the memory can further be configured to select a third PCI for the first scheduling entity. The third PCI corresponds to a third PSS waveform different than the first PSS waveform to avoid colliding with the second PSS waveform. The processor and the memory can further be configured to transmit a PCI change indication including the third PCI to the first scheduling entity to initiate a change from the first PCI to the third PCI within the first scheduling entity. The first PSS waveform and the second PSS waveform are identical.

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, and 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 RAN <NUM> may implement any suitable radio access technology (RAT) or RATs to provide radio access to the UE <NUM>. As one example, the RAN <NUM> may operate according to 3rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as <NUM>. In another example, the RAN <NUM> may operate according to both the LTE and <NUM> NR standards.

In examples where the RAN <NUM> operates according to both the LTE and <NUM> NR standards, one of the base stations <NUM> may be an LTE base station, while another base station may be a <NUM> NR base station.

The radio access network <NUM> is further illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus may be referred to as user equipment (UE) <NUM> in 3GPP standards, but may also be referred to by those skilled in the art as a mobile station (MS), 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 (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be an apparatus that provides a user with access to network services. In examples where the RAN <NUM> operates according to both the LTE and <NUM> NR standards, the UE <NUM> may be an Evolved-Universal Terrestrial Radio Access Network - New Radio dual connectivity (EN-DC) UE that is capable of simultaneously connecting to an LTE base station and a NR base station to receive data packets from both the LTE base station and the NR base station.

Within the present document, a "mobile" apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. UEs may include a number of hardware structural components sized, shaped, and arranged to help in communication; such components can include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC), a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA), and a broad array of embedded systems, e.g., corresponding to an "Internet of Things" (IoT). A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player), a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid), lighting, water, etc., an industrial automation and enterprise device, a logistics controller, agricultural equipment, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, i.e., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data.

Transmissions over the air interface from a base station (e.g., base station <NUM>) to one or more UEs (e.g., UE <NUM>) maybe referred to as downlink (DL) transmission.

In addition, the uplink and/or downlink control information and/or traffic information may be time-divided into frames, subframes, slots, and/or symbols. As used herein, a symbol may refer to a unit of time that, in an orthogonal frequency division multiplexed (OFDM) waveform, carries one resource element (RE) per sub-carrier. A slot may carry <NUM> or <NUM> OFDM symbols. A subframe may refer to a duration of <NUM>. Multiple subframes or slots may be grouped together to form a single frame or radio frame. Of course, these definitions are not required, and any suitable scheme for organizing waveforms may be utilized, and various time divisions of the waveform may have any suitable duration.

Referring now to <FIG>, by way of example and without limitation, a schematic illustration of a RAN <NUM> is provided. In some examples, the RAN <NUM> may be the same as the RAN <NUM> described above and illustrated in <FIG>. The geographic area covered by the RAN <NUM> may be divided into cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted from one access point or base station. <FIG> illustrates macrocells <NUM>, <NUM>, and <NUM>, and a small cell <NUM>, each of which may include one or more sectors (not shown). A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell.

Within the RAN <NUM>, the cells may include UEs that may be in communication with one or more sectors of each cell. Further, each base station <NUM>, <NUM>, <NUM>, and <NUM> may be configured to provide an access point to a core network <NUM> (see <FIG>) for all the UEs in the respective cells. For example, UEs <NUM> and <NUM> may be in communication with base station <NUM>; UEs <NUM> and <NUM> may be in communication with base station <NUM>; UEs <NUM> and <NUM> may be in communication with base station <NUM> by way of RRH <NUM>; and UE <NUM> may be in communication with base station <NUM>. In some examples, the UEs <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> may be the same as the UE/scheduled entity <NUM> described above and illustrated in <FIG>.

In some examples, an unmanned aerial vehicle (UAV) <NUM>, which may be a drone or quadcopter, can be a mobile network node and may be configured to function as a UE. For example, the UAV <NUM> may operate within cell <NUM> by communicating with base station <NUM>.

In a further aspect of the RAN <NUM>, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, two or more UEs (e.g., UEs <NUM> and <NUM>) may communicate with each other using peer to peer (P2P) or sidelink signals <NUM> without relaying that communication through a base station (e.g., base station <NUM>). In a further example, UE <NUM> is illustrated communicating with UEs <NUM> and <NUM>. Here, the UE <NUM> may function as a scheduling entity or a primary sidelink device, and UEs <NUM> and <NUM> may function as a scheduled entity or a non-primary (e.g., secondary) sidelink device. In still another example, a UE may function as a scheduling entity in a device-to-device (D2D), peer-to-peer (P2P), or vehicle-to-vehicle (V2V) network, and/or in a mesh network. In a mesh network example, UEs <NUM> and <NUM> may optionally communicate directly with one another in addition to communicating with the scheduling entity <NUM>. Thus, in a wireless communication system with scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate utilizing the scheduled resources. In some examples, the sidelink signals <NUM> include sidelink traffic (e.g., a physical sidelink shared channel) and sidelink control (e.g., a physical sidelink control channel).

In the radio access network <NUM>, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of an access and mobility management function (AMF, not illustrated, part of the core network <NUM> in <FIG>), which may include a security context management function (SCMF) that manages the security context for both the control plane and the user plane functionality, and a security anchor function (SEAF) that performs authentication.

A radio access network <NUM> may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE's connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE <NUM> (illustrated as a vehicle, although any suitable form of UE may be used) may move from the geographic area corresponding to its serving cell <NUM> to the geographic area corresponding to a neighbor cell <NUM>. When the signal strength or quality from the neighbor cell <NUM> exceeds that of its serving cell <NUM> for a given amount of time, the UE <NUM> may transmit a reporting message to its serving base station <NUM> indicating this condition. In response, the UE <NUM> may receive a handover command, and the UE may undergo a handover to the cell <NUM>.

In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the base stations <NUM>, <NUM>, and <NUM>/<NUM> may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs), unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH)). The UEs <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may receive the unified synchronization signals, derive the carrier frequency and slot timing from the synchronization signals, and in response to deriving timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE <NUM>) may be concurrently received by two or more cells (e.g., base stations <NUM> and <NUM>/<NUM>) within the radio access network <NUM>. Each of the cells may measure a strength of the pilot signal, and the radio access network (e.g., one or more of the base stations <NUM> and <NUM>/<NUM> and/or a central node within the core network) may determine a serving cell for the UE <NUM>. As the UE <NUM> moves through the radio access network <NUM>, the network may continue to monitor the uplink pilot signal transmitted by the UE <NUM>. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network <NUM> may handover the UE <NUM> from the serving cell to the neighboring cell, with or without informing the UE <NUM>.

In various implementations, the air interface in the radio access network <NUM> may utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum provides for exclusive use of a portion of the spectrum, generally by virtue of a mobile network operator purchasing a license from a government regulatory body. Unlicensed spectrum provides for shared use of a portion of the spectrum without need for a government-granted license. While compliance with some technical rules is generally still required to access unlicensed spectrum, generally, any operator or device may gain access. Shared spectrum may fall between licensed and unlicensed spectrum, wherein technical rules or limitations may be required to access the spectrum, but the spectrum may still be shared by multiple operators and/or multiple RATs. For example, the holder of a license for a portion of licensed spectrum may provide licensed shared access (LSA) to share that spectrum with other parties, e.g., with suitable licensee-determined conditions to gain access.

The air interface in the radio access network <NUM> may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, <NUM> NR specifications provide multiple access for UL transmissions from UEs <NUM> and <NUM> to base station <NUM>, and for multiplexing for DL transmissions from base station <NUM> to one or more UEs <NUM> and <NUM>, utilizing orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP). In addition, for UL transmissions, <NUM> NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred to as single-carrier FDMA (SC-FDMA)). However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes, and may be provided utilizing time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other suitable multiple access schemes. Further, multiplexing DL transmissions from the base station <NUM> to UEs <NUM> and <NUM> may be provided utilizing time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing schemes.

The air interface in the radio access network <NUM> may further utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full duplex means both endpoints can simultaneously communicate with one another. Half duplex means only one endpoint can send information to the other at a time. In a wireless link, a full duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or time division duplex (TDD). In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some times the channel is dedicated for transmissions in one direction, while at other times the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per slot.

Various aspects of the present disclosure will be described with reference to an OFDM waveform, an example of which is schematically illustrated in <FIG>. It should be understood by those of ordinary skill in the art that the various aspects of the present disclosure may be applied to an SC-FDMA waveform in substantially the same way as described herein below. That is, while some examples of the present disclosure may focus on an OFDM link for clarity, it should be understood that the same principles may be applied as well to SC-FDMA waveforms.

Referring now to <FIG>, an expanded view of an exemplary DL subframe <NUM> is illustrated, showing an OFDM resource grid. However, as those skilled in the art will readily appreciate, the PHY transmission structure for any particular application may vary from the example described here, depending on any number of factors. Here, time is in the horizontal direction with units of OFDM symbols; and frequency is in the vertical direction with units of subcarriers.

The resource grid <NUM> may be used to schematically represent time-frequency resources for a given antenna port. That is, in a multiple-input-multiple-output (MIMO) implementation with multiple antenna ports available, a corresponding multiple number of resource grids <NUM> may be available for communication. The resource grid <NUM> is divided into multiple resource elements (REs) <NUM>. An RE, which is <NUM> subcarrier × <NUM> symbol, is the smallest discrete part of the time-frequency grid, and contains a single complex value representing data from a physical channel or signal. Depending on the modulation utilized in a particular implementation, each RE may represent one or more bits of information. In some examples, a block of REs may be referred to as a physical resource block (PRB) or more simply a resource block (RB) <NUM>, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB may include <NUM> subcarriers, a number independent of the numerology used. In some examples, depending on the numerology, an RB may include any suitable number of consecutive OFDM symbols in the time domain. Within the present disclosure, it is assumed that a single RB such as the RB <NUM> entirely corresponds to a single direction of communication (either transmission or reception for a given device).

A UE generally utilizes only a subset of the resource grid <NUM>. An RB may be the smallest unit of resources that can be allocated to a UE. Thus, the more RBs scheduled for a UE, and the higher the modulation scheme chosen for the air interface, the higher the data rate for the UE.

Each <NUM> subframe <NUM> may consist of one or multiple adjacent slots. In the example shown in <FIG>, one subframe <NUM> includes four slots <NUM>, as an illustrative example. In some examples, a slot may be defined according to a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a slot may include <NUM> or <NUM> OFDM symbols with a nominal CP. Additional examples may include mini-slots having a shorter duration (e.g., one or two OFDM symbols). These mini-slots may in some cases be transmitted occupying resources scheduled for ongoing slot transmissions for the same or for different UEs.

An expanded view of one of the slots <NUM> illustrates the slot <NUM> including a control region <NUM> and a data region <NUM>. In general, the control region <NUM> may carry control channels (e.g., PDCCH), and the data region <NUM> may carry data channels (e.g., PDSCH or PUSCH). Of course, a slot may contain all DL, all UL, or at least one DL portion and at least one UL portion. The simple structure illustrated in <FIG> is merely exemplary in nature, and different slot structures may be utilized, and may include one or more of each of the control region(s) and data region(s).

Although not illustrated in <FIG>, the various REs <NUM> within a RB <NUM> may be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other REs <NUM> within the RB <NUM> may also carry pilots or reference signals, including but not limited to a demodulation reference signal (DMRS) or a sounding reference signal (SRS). These pilots or reference signals may provide for a receiving device to perform channel estimation of the corresponding channel, which may enable coherent demodulation/detection of the control and/or data channels within the RB <NUM>.

In a DL transmission, the transmitting device (e.g., the scheduling entity) may allocate one or more REs <NUM> (e.g., within a control region <NUM>) to carry DL control information including one or more DL control channels, such as a PBCH; a physical control format indicator channel (PCFICH); a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH); and/or a physical downlink control channel (PDCCH), etc., to one or more scheduled entities. The transmitting device may further allocate one or more REs <NUM> to carry other DL signals, such as a DMRS; a phase-tracking reference signal (PT-RS); a channel state information - reference signal (CSI-RS); a primary synchronization signal (PSS); and a secondary synchronization signal (SSS).

The synchronization signals PSS and SSS, and in some examples, the PBCH and a PBCH DMRS, may be transmitted in a synchronization signal block (SSB) that includes <NUM> consecutive OFDM symbols, numbered via a time index in increasing order from <NUM> to <NUM>. In the frequency domain, the SSB may extend over <NUM> contiguous subcarriers, with the subcarriers being numbered via a frequency index in increasing order from <NUM> to <NUM>. Of course, the present disclosure is not limited to this specific SSB configuration. Other nonlimiting examples may utilize greater or fewer than two synchronization signals; may include one or more supplemental channels in addition to the PBCH; may omit a PBCH; and/or may utilize a different number of symbols and/or nonconsecutive symbols for an SSB, within the scope of the present disclosure.

The PBCH may further include a master information block (MIB) that includes various system information, along with parameters for decoding a system information block (SIB). The SIB may be, for example, a SystemInformationType1 (SIB1) that may include various additional system information. Examples of system information may include, but are not limited to, subcarrier spacing, system frame number, cell bar indication, a list of common control resource sets (CoreSets) (e.g., PDCCH CoreSet0 or CoreSet1), a list of common search spaces, a search space for SIB1, a paging search space, a random access search space, and uplink configuration information.

The PCFICH provides information to assist a receiving device in receiving and decoding the PDCCH. The PDCCH carries downlink control information (DCI) including but not limited to power control commands, scheduling information, a grant, and/or an assignment of REs for DL and UL transmissions. The PHICH carries HARQ feedback transmissions such as an acknowledgment (ACK) or negative acknowledgment (NACK). HARQ is a technique well-known to those of ordinary skill in the art, wherein the integrity of packet transmissions may be checked at the receiving side for accuracy, e.g., utilizing any suitable integrity checking mechanism, such as a checksum or a cyclic redundancy check (CRC). If the integrity of the transmission is confirmed, an ACK may be transmitted, whereas if not confirmed, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission, which may implement chase combining, incremental redundancy, etc..

In an UL transmission, the transmitting device (e.g., the scheduled entity) may utilize one or more REs <NUM> to carry UL control information including one or more UL control channels, such as a physical uplink control channel (PUCCH), to the scheduling entity. UL control information may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. For example, the UL control information may include a DMRS or SRS. In some examples, the control information may include a scheduling request (SR), i.e., request for the scheduling entity to schedule uplink transmissions. Here, in response to the SR transmitted on the control channel, the scheduling entity may transmit downlink control information that may schedule resources for uplink packet transmissions. UL control information may also include HARQ feedback, channel state feedback (CSF), or any other suitable UL control information.

In addition to control information, one or more REs <NUM> (e.g., within the data region <NUM>) may be allocated for user data or traffic data. Such traffic may be carried on one or more traffic channels, such as, for a DL transmission, a PDSCH; or for an UL transmission, a physical uplink shared channel (PUSCH). In some examples, one or more REs <NUM> within the data region <NUM> may be configured to carry SIBs (e.g., SIB1), carrying system information that may enable access to a given cell.

The channels or carriers described above with reference to <FIG> are not necessarily all of the channels or carriers that may be utilized between a scheduling entity and scheduled entities, and those of ordinary skill in the art will recognize that other channels or carriers may be utilized in addition to those illustrated, such as other traffic, control, and feedback channels.

<FIG> is a schematic diagram providing a high-level illustration of one example of an Integrated-Access-Backhaul (IAB) network configuration <NUM> that may be utilized in some aspects of the disclosure. In this illustration, a communication network <NUM>, such as an IAB network, is coupled to a remote network <NUM>, such as a main backhaul network or mobile core network. In such an IAB network <NUM>, the wireless spectrum may be used for both access links and backhaul links.

The IAB network <NUM> maybe similar to the radio access network <NUM> shown in <FIG>, in that the IAB network <NUM> may be divided into a number cells <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, each of which may be served by a respective IAB node <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Each of the IAB nodes <NUM>-<NUM> may be an access point, base station (BS), eNB, gNB, or other node that utilizes wireless spectrum (e.g., the radio frequency (RF) spectrum) to support access for one or more UEs located within the cells <NUM>-<NUM> served by the IAB nodes. Each cell <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> is assigned a respective physical cell identifier (PCI), which is used to identify the respective cell in the IAB network <NUM>. In <NUM> (New Radio) systems, there are <NUM> supported values for the PCI. The PCI may be reused by multiple geographically separated cells in the IAB network <NUM>. In this example, cells with the same PCI may be distinguished by their unique cell global identifier (NCGI).

In the example shown in <FIG>, IAB node <NUM> communicates with UEs <NUM> and <NUM> via wireless access links <NUM> and <NUM>, IAB node <NUM> communicates with UE <NUM> via wireless access link <NUM>, and IAB node <NUM> communicates with UE <NUM> via wireless access link <NUM>. The IAB nodes <NUM>-<NUM> are further interconnected via one or more wireless backhaul links <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Each of the wireless backhaul links <NUM>-<NUM> may utilize the same wireless spectrum (e.g., the radio frequency (RF) spectrum) as the access links <NUM>-<NUM> to backhaul access traffic to/from the remote network <NUM>. This may be referred to as wireless self-backhauling. Such wireless self-backhauling can enable fast and easy deployment of highly dense small cell networks. That is, rather than requiring each new gNB deployment to be outfitted with its own hardwired backhaul connection, the wireless spectrum utilized for communication between the gNB and UE may be leveraged for backhaul communication between any numbers of IAB nodes to form the IAB network <NUM>.

In the example shown in <FIG>, IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>, IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>, IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>, IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>, IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>, and IAB node <NUM> communicates with IAB node <NUM> via wireless backhaul link <NUM>. As shown in <FIG>, each IAB node <NUM>-<NUM> may be connected via respective wireless backhaul links <NUM>-<NUM> to two or more other IAB nodes for robustness.

Some or all of the IAB nodes <NUM>-<NUM> may also be connected via wired backhaul links (e.g., fiber, coaxial cable, Ethernet, copper wires, etc.) and/or microwave backhaul links. Thus, the IAB network <NUM> may support both wired/microwave and wireless backhaul traffic. At least one of the IAB nodes (e.g., IAB node <NUM>) may be a border IAB node that also provides a communication link <NUM> to the remote network <NUM>. For example, the border IAB node <NUM> may include a wired (e.g., fiber, coaxial cable, Ethernet, copper wires), microwave, or other suitable link <NUM> to the remote network <NUM>.

To facilitate wireless communication between the IAB nodes <NUM>-<NUM> and between the IAB nodes <NUM>-<NUM> and the UEs served by the IAB nodes <NUM>-<NUM>, each IAB node <NUM>-<NUM> may be configured to operate as both a scheduling entity and a scheduled entity. Thus, an IAB node (e.g., IAB node <NUM>) may utilize the same wireless spectrum (e.g., the radio frequency (RF) spectrum) to transmit access traffic to/from UEs and to then backhaul that access traffic to/from the remote network <NUM>. For example, to backhaul access traffic to/from IAB node <NUM>, IAB node <NUM> may communicate with IAB node <NUM> to transmit backhaul access traffic via wireless backhaul link <NUM>, IAB node <NUM> may communicate with IAB node <NUM> to transmit the backhaul access traffic via wireless backhaul link <NUM>, and IAB node <NUM> may communicate with IAB node <NUM> to transmit the backhaul access traffic via wireless backhaul link <NUM>. In this example, IAB nodes <NUM> and <NUM> may each operate as both a scheduling entity and a scheduled entity to backhaul access traffic to/from IAB node <NUM>. As such, communication between a pair of IAB nodes may be individually scheduled by one of the IAB nodes within the pair.

In other examples, an IAB node may schedule wireless backhaul communications between other pairs of IAB nodes. For example, IAB node <NUM> may operate as the scheduling entity for the IAB network <NUM>, while IAB nodes <NUM>, <NUM>, and <NUM> each operate as a scheduled entity to backhaul access traffic to/from IAB node <NUM>. In this example, IAB node <NUM> may schedule wireless backhaul communications between each of the pairs of IAB nodes (e.g., between IAB node <NUM> and IAB node <NUM>, between IAB node <NUM> and IAB node <NUM>, and between IAB node <NUM> and IAB node <NUM>). As another example, IAB node <NUM> may operate as a scheduling entity to schedule wireless backhaul communications between IAB nodes <NUM> and <NUM> and also between IAB node <NUM> and IAB node <NUM>. IAB node <NUM> may then operate as a scheduled entity to allow IAB node <NUM> to schedule wireless backhaul communications therebetween.

<FIG> is a schematic diagram illustrating an example of IAB node functionality within an IAB network <NUM>. In the example shown in <FIG>, an IAB node <NUM> is shown coupled to a core network <NUM> via a wireline connection. This IAB node <NUM> may be referred to herein as an IAB donor node, which may be, for example, an enhanced gNB including functionality for controlling the IAB network <NUM>. In some examples, the IAB donor node <NUM> may include a central unit (CU) <NUM> and a distributed unit (DU) <NUM>. The CU <NUM> is configured to operate as a centralized network node (or central entity) within the IAB network <NUM>. For example, the CU <NUM> may include radio resource control (RRC) layer functionality and packet data convergence protocol (PDCP) layer functionality to control/configure the other nodes (e.g., IAB nodes and UEs) within the IAB network <NUM>.

The DU <NUM> is configured to operate as a scheduling entity to schedule scheduled entities (e.g., other IAB nodes and UEs) of the IAB donor node <NUM>. For example, the DU <NUM> of the IAB donor node <NUM> may operate as a scheduling entity to schedule IAB nodes <NUM> and <NUM> and UEs <NUM> and <NUM>. Thus, the DU <NUM> of the IAB donor node <NUM> may schedule communication with IAB nodes <NUM> and <NUM> via respective backhaul links and schedule communication with UEs <NUM> and <NUM> via respective access links. In some examples, the DU <NUM> may include the radio link control (RLC), medium access control (MAC), and physical (PHY) layer functionality to enable operation as a scheduling entity.

Each of the IAB nodes <NUM> and <NUM> maybe configured as a Layer <NUM> (L2) relay node including a respective DU <NUM> and a mobile termination (MT) unit <NUM> to enable each L2 relay IAB node <NUM> and <NUM> to operate as a scheduling entity and a scheduled entity. For example, the MT unit <NUM> within each of the L2 relay IAB nodes <NUM> and <NUM> is configured to operate as a scheduled entity that may be scheduled by the IAB donor node <NUM>. Each MT unit <NUM> within the L2 relay IAB nodes <NUM> and <NUM> further facilitates communication with the IAB donor node <NUM> via respective backhaul links. In addition, the DU <NUM> within each of the L2 relay IAB nodes <NUM> and <NUM> operates similar to the DU <NUM> within the IAB donor node <NUM> to function as a scheduling entity to schedule one or more respective scheduled entities (e.g., other IAB nodes and/or UEs) of the L2 relay IAB nodes <NUM> and <NUM>.

For example, the DU <NUM> of L2 relay IAB node <NUM> functions as a scheduling entity to schedule communication with a UE <NUM> via an access link, while the DU <NUM> of L2 relay IAB node <NUM> functions as a scheduling entity to schedule communication with the MT units <NUM> of L2 relay IAB nodes <NUM> and <NUM> via respective backhaul links and a UE <NUM> via an access link. Each of the L2 relay IAB nodes <NUM> and <NUM> further includes a respective DU <NUM> that functions as a scheduling entity to communicate with respective UEs <NUM> and <NUM>. Thus, in the network topology illustrated in <FIG>, since IAB donor node <NUM> is configured to control each of the other nodes in the IAB network, the IAB donor node <NUM> is a parent IAB node of child IAB nodes <NUM>, <NUM>, <NUM> and <NUM>. In addition, IAB node <NUM> is further a parent IAB node of child IAB nodes <NUM> and <NUM>. For example, the CU <NUM> and DU <NUM> within IAB donor node <NUM> may function as the parent IAB node of child IAB nodes <NUM>, <NUM>, <NUM>, and <NUM> and the DU <NUM> within IAB node <NUM> may function as the parent IAB node of child IAB nodes <NUM> and <NUM>. The MT unit <NUM> within IAB nodes <NUM>, <NUM>, <NUM>, and <NUM> may further function as child IAB nodes.

In a mobile IAB network, one or more of the L2 relay IAB nodes <NUM>, <NUM>, <NUM>, and/or <NUM> maybe moving within the IAB network <NUM>. For example, an L2 relay IAB node (e.g., IAB node <NUM>) may be a mobile IAB node installed on a bus, train, taxi, or other moveable object. As the mobile IAB node <NUM> moves through the IAB network <NUM>, the parent IAB node of the mobile IAB node <NUM> may change through a topology adaptation procedure. However, as the mobile IAB node <NUM> moves through the IAB network <NUM>, a PCI collision may occur between the mobile IAB node <NUM> and another stationary or mobile L2 relay IAB node serving a cell assigned the same PCI. In addition, a PCI collision may also occur in a fixed IAB network <NUM> that utilizes zero-network planning (e.g., for an over-deployed network in which gNBs are added in an ad-hoc manner).

When two neighboring cells are assigned the same PCI, a scheduled entity (e.g., a UE or child IAB node) may not be able to differentiate reference signals from each of the neighboring cells, since the reference signals are scrambled based on the same PCI. In addition, a PCI collision between two neighboring cells may lead to timing synchronization and channel estimation issues at the UE, and may result in decoding failure of user data traffic transmitted from one of the two neighboring cells. Therefore, to mitigate PCI collision issues, the PCI for one of the two neighboring cells may be changed from an old PCI (e.g., the colliding PCI) to a new PCI.

However, even after PCI collision management resulting in two neighboring cells utilizing different PCIs, the two neighboring cells may still transmit the same PSS, resulting in a PSS collision between the neighboring cells. The PSS and SSS waveforms each depend upon the PCI. However, for the PSS, there are only three waveform options, and the choice of PSS waveform option is a function of the PCI as mod(PCI, <NUM>). For example, the PCI ( <MAT>) may be defined by the equation: <MAT> where <MAT> is the SSS whose value is selected from the group {<NUM>, <NUM>,. , <NUM>} and <MAT> is the PSS whose value is selected from the group {<NUM>, <NUM>, <NUM>}.

When two neighboring cells have overlapping coverage areas, a scheduled entity (e.g., a UE or child IAB node) within the overlapping coverage area may receive signals (e.g., SSBs) from both cells. If each cell transmits the same PSS waveform, the ability of the scheduled entity to perform a cell search in idle or connected mode may be affected, along with tracking synchronization in the serving cell and beam management and beam tracking in the serving cell.

For example, when two neighboring cells transmit the same PSS and different SSS, the scheduled entity receiving each PSS from each neighboring cell observes a composite PSS channel that is different from the SSS channel. In general, the combined signal received by the scheduled entity from two neighboring cells may be represented as: <MAT> where x<NUM> and x<NUM> are the respective signals transmitted by each of the neighboring cells, h<NUM> and h<NUM> are the respective channels between the scheduled entity and each of the neighboring cells, and n represents the noise.

When both neighboring cells transmit the same PSS, x<NUM> = x<NUM>, and therefore, each PSS may be represented by the variable p in Equation <NUM>, such that: <MAT> After descrambling (e.g., utilizing the PCI of the serving cell (PCIi)), the channel corresponding to the received PSS is a composite channel, which may be represented by: <MAT>.

By contrast, when neighboring cells transmit different SSS that are orthogonal or pseudo-orthogonal (e.g., in the code domain) to one another, x<NUM> = s<NUM> and x<NUM> = s<NUM>, and therefore, the combined SSS received at the scheduled entity may be represented as: <MAT> After descrambling (e.g., utilizing PCI<NUM>), the signal s<NUM> may be removed (e.g., as a result of the orthogonality or pseudo-orthogonality of the two signals), and as such, the channel corresponding to the received SSS includes only the channel between the scheduled entity and the serving cell, as shown in the below equation: <MAT> Thus, when neighboring cells transmit the same PSS waveform, but different SSS waveforms, the receiving scheduled entity may not be able to distinguish between the cells. The PSS collision may occur as a result of a PCI collision and selection of a new PCI that produces the same PSS waveform as a neighboring cell, a mobile IAB node moving into a coverage area of a neighboring cell utilizing the same PSS waveform, or zero-network planning.

Various aspects of the present disclosure are directed to a PCI update mechanism in which a first scheduling entity (e.g., gNB or parent IAB node) utilizing a first (or old) PCI to communicate with a set of one or more scheduled entities may change to using a second (or new) PCI to communicate with the set of one or more scheduled entities, where the first PCI corresponds to a first PSS waveform and the second PCI corresponds to a second PSS waveform different than the first PSS waveform. In some examples, the first scheduling entity may change to using the second PCI upon detecting a collision between the first PCI utilized by the first scheduling entity and a third PCI utilized by a second scheduling entity located proximate to the first scheduling entity, such that the first PCI and the third PCI are identical. Here, a first coverage area of the first scheduling entity may overlap a second coverage area of the second scheduling entity. In other examples, the first scheduling entity may change to using the second PCI upon detecting a collision between the first PSS waveform transmitted by the first scheduling entity and a third PSS waveform transmitted by the second scheduling entity, such that the first PSS waveform and the third PSS waveform are identical. In some examples, the first scheduling entity may change from the first PCI to the second PCI upon receipt of a PCI change indication from a centralized network node. In other examples, the first scheduling entity may autonomously change from the first PCI to the second PCI.

<FIG> illustrates an example of a PCI change procedure that may be performed, for example, within an IAB network <NUM>. In the example shown in <FIG>, a centralized network node associated with the IAB network <NUM> renders the decision on whether to perform the PCI change for the scheduling entity (e.g., an IAB-DU <NUM>, which may be, for example, a DU within an L2 relay IAB node). The centralized network node may be, for example, a network entity configured for PCI management, a base station (e.g., gNB or eNB) with a larger coverage area in the IAB network <NUM> (e.g., a parent IAB node or other base station with a larger coverage area than the IAB-DU <NUM>), or an IAB-CU <NUM> (e.g., within an IAB donor node) of the IAB network <NUM>, the latter being illustrated in <FIG>. As shown in <FIG>, the centralized network node (e.g., IAB-CU <NUM>) is in communication with the IAB-DU <NUM> via one or more backhaul links.

At <NUM>, the IAB-CU <NUM> identifies a PSS collision associated with the IAB-DU <NUM>. For example, the PSS collision may be between the IAB-DU <NUM> and a neighboring IAB-DU (not shown, for simplicity). Here, the coverage areas of the IAB-DU <NUM> and neighboring IAB-DU may at least partially overlap. In some examples, the IAB-CU <NUM> may identify the PSS collision through topology adaptation procedures performed as a result of a mobile IAB node, neighbor list updates provided by L2 relay IAB nodes, and/or information provided by other network nodes (e.g., child IAB nodes and/or UEs). In some examples, the PSS collision may result from a PCI collision between the IAB-DU <NUM> and the neighboring IAB-DU. In other examples, the PSS collision may result from different PCIs between the IAB-DU <NUM> and neighboring IAB-DU producing the same PSS waveform. Upon discovering the PSS collision, at <NUM>, the IAB-CU <NUM> assigns a new PCI to the IAB-DU <NUM>. The new PCI is selected to produce a different PSS waveform than the PCI assigned to the neighboring IAB-DU. At <NUM>, the IAB-CU <NUM> then transmits a message (e.g., an RRC message) including a PCI change indication with the new PCI to the IAB-DU <NUM>. In some examples, the message including the PCI change indication may be a signal defined at the F1-AP interface between the IAB-CU <NUM> and the IAB-DU <NUM>.

At <NUM>, the IAB-DU <NUM> changes to using the new PCI to identify a cell served by the IAB-DU <NUM> and generate PSS/SSS waveforms. At <NUM>, the IAB-DU <NUM> may transmit a message including a PCI change complete indication to the IAB-CU <NUM> after completing the change to the new PCI. At <NUM>, the IAB-CU <NUM> may update one or more neighbor lists with the new PCI and provide the updated neighbor lists to neighboring IAB nodes of the IAB-DU <NUM>. In examples in which a centralized network node other than the IAB-CU <NUM> decides to perform the PCI change, the centralized network node may transmit a signal indicating the PCI change to the IAB-DU <NUM> and may further transmit another signal indicating the PCI change to the IAB-CU <NUM> to enable the IAB-CU <NUM> to update the neighbor list(s) with the new PCI of the IAB-DU <NUM>. In some examples, the IAB-CU <NUM> may further coordinate with neighbor IAB nodes (e.g., gNBs and/or eNBs) of the IAB-DU <NUM> via an Xn/X2 interface to update a mapping between the new PCI and the NCGI associated with the IAB-DU <NUM>.

<FIG> is a diagram illustrating another example of a soft PCI change procedure that may be performed, for example, within an IAB network <NUM>. In the example shown in <FIG>, an IAB-DU <NUM> (e.g., a DU within an L2 relay IAB node) may autonomously decide to initiate the PCI change and may communicate the PCI change decision to an IAB-CU <NUM> (e.g., a CU within an IAB donor node). In this example, the IAB-DU <NUM> may be within an RRC-enhanced IAB node that is capable of implementing at least part of the RRC functionality.

At <NUM>, the IAB-DU <NUM> identifies a PSS collision associated with the IAB-DU <NUM>. For example, the PSS collision may be between the IAB-DU <NUM> and a neighboring IAB-DU (not shown, for simplicity). Here, the coverage areas of the IAB-DU <NUM> and the neighboring IAB-DU may at least partially overlap. In some examples, the IAB-DU <NUM> may identify the PSS collision through neighbor list updates, neighbor cell searches (e.g., inter-IAB node discovery), or information provided by a scheduled entity or other network node. For example, a scheduled entity may identify the PSS collision upon receiving and processing PSS/SSS from both the IAB-DU <NUM> and the neighboring IAB-DU. As another example, a parent IAB-node of the IAB-DU <NUM> or other IAB node in the IAB network <NUM> may discover the PSS collision through network topology adaptation procedures, neighbor list updates, neighbor cell searches, and/or other information provided by other nodes in the IAB network <NUM>.

In some examples, the PSS collision may result from a PCI collision between the IAB-DU <NUM> and the neighboring IAB-DU. In other examples, the PSS collision may result from different PCIs between the IAB-DU <NUM> and neighboring IAB-DU producing the same PSS waveform. Upon discovering the PSS collision, at <NUM>, the IAB-DU <NUM> may select a new PCI to produce a different PSS waveform than the PCI assigned to the neighboring IAB-DU. At <NUM>, the IAB-DU <NUM> transmits a message including a PCI change notification to the IAB-CU <NUM>. In other examples, the IAB-DU <NUM> may transmit a request for a PCI change to the IAB-CU <NUM>, which may then assign the new PCI to the IAB-DU <NUM>. At <NUM>, the IAB-CU <NUM> may update one or more neighbor lists with the new PCI and provide the updated neighbor lists to neighboring IAB nodes of the IAB-DU <NUM>.

<FIG> is a block diagram illustrating an example of a hardware implementation for a scheduling entity <NUM> employing a processing system <NUM>. For example, the scheduling entity <NUM> may be a base station (e.g., eNB, gNB), IAB donor node (e.g., DU of an IAB donor node), L2 relay IAB node (e.g., DU of an L2 relay donor node), or other scheduling entity as illustrated in any one or more of <FIG>, <FIG>, and/or <NUM>-<NUM>.

The scheduling entity <NUM> may be implemented with a processing system <NUM> that includes one or more processors <NUM>. Examples of processors <NUM> include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the scheduling entity <NUM> maybe configured to perform any one or more of the functions described herein. That is, the processor <NUM>, as utilized in a scheduling entity <NUM>, may be used to implement any one or more of the processes and procedures described below.

In this example, the processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> communicatively couples together various circuits including one or more processors (represented generally by the processor <NUM>), a memory <NUM>, and computer-readable media (represented generally by the computer-readable medium <NUM>). The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface <NUM> provides an interface between the bus <NUM> and a transceiver <NUM>. The transceiver <NUM> provides a communication interface or means for communicating with various other apparatus over a transmission medium (e.g., air). Depending upon the nature of the apparatus, a user interface <NUM> (e.g., keypad, display, speaker, microphone, joystick, touchscreen) may also be provided. Of course, such a user interface <NUM> is optional, and may be omitted in some examples.

One or more processors <NUM> in the processing system may execute software. The software may reside on a computer-readable medium <NUM>.

The computer-readable medium <NUM> may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD)), a smart card, a flash memory device (e.g., a card, a stick, or a key drive), a random access memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium <NUM> may reside in the processing system <NUM>, external to the processing system <NUM>, or distributed across multiple entities including the processing system <NUM>. The computer-readable medium <NUM> may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

In some aspects of the disclosure, the processor <NUM> may include circuitry configured for various functions. For example, the processor <NUM> may include resource assignment and scheduling circuitry <NUM>, configured to generate, schedule, and modify a resource assignment or grant of time-frequency resources (e.g., a set of one or more resource elements) in one or more beam directions. For example, the resource assignment and scheduling circuitry <NUM> may schedule time-frequency resources within a plurality of time division duplex (TDD) and/or frequency division duplex (FDD) slots to carry user data traffic and/or control information to and/or from a set of one or more scheduled entities (e.g., UEs or child IAB nodes). Thus, the resource assignment and scheduling circuitry <NUM> may be configured within a DU of an IAB donor node or L2 relay IAB node.

In some examples, the resource assignment and scheduling circuitry <NUM> may be configured to schedule an SSB including a PSS and SSS carrying the PCI of a cell served by the scheduling entity <NUM>. In examples in which the scheduling entity <NUM> is an L2 relay IAB node that autonomously determines to initiate a PCI change from a first PCI <NUM> to a second PCI <NUM>, the resource assignment and scheduling circuitry <NUM> maybe configured to schedule transmission of a message including a PCI change notification (or PCI change request) to a centralized network node, such as an IAB donor node (e.g., IAB-CU), within the IAB network. The first PCI <NUM> and second PCI <NUM> may be stored, for example, in memory <NUM>. The resource assignment and scheduling circuitry <NUM> may further be configured to execute resource assignment and scheduling software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include communication and processing circuitry <NUM>, configured to communicate with a set of one or more scheduled entities (e.g., UEs or child IAB nodes). In some examples, the communication and processing circuitry <NUM> may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission). For example, the communication and processing circuitry <NUM> may be configured to generate and transmit an SSB including a PSS and SSS carrying the PCI of the cell served by the scheduling entity <NUM>.

In examples in which the scheduling entity <NUM> is an L2 relay IAB node, the communication and processing circuitry <NUM> may be configured to receive a message (e.g., RRC signal) including a PCI change indication from a centralized network node (e.g., an IAB donor node, such as an IAB-CU) to initiate the PCI change from the first PCI <NUM> to the second PCI <NUM>. The communication and processing circuitry <NUM> may further be configured to store the second PCI <NUM> included within the PCI change indication within memory <NUM>. In examples in which the scheduling entity <NUM> is an L2 relay IAB node that autonomously initiates a PCI change, the communication and processing circuitry <NUM> may be configured to generate and transmit, via the transceiver <NUM>, a PCI change notification including the second PCI <NUM> (or a PCI change request that requests the second PCI <NUM>) to an IAB donor node within the IAB network. The communication and processing circuitry <NUM> may further be configured to execute communication and processing software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include PSS collision detection circuitry <NUM>, configured to detect a PSS collision between two neighboring IAB nodes. In some examples, the PSS collision detection circuitry <NUM> may be configured to detect the PSS collision between the scheduling entity <NUM> and a neighboring IAB node (e.g., another L2 relay IAB node located proximate to the scheduling entity <NUM> having a coverage area that may at least partially overlap the coverage area of the scheduling entity <NUM>) through neighbor list <NUM> updates (e.g., which may be stored, for example, in memory <NUM>), neighbor cell searches (e.g., inter-IAB node discovery), or information provided by a scheduled entity or other network node. For example, a scheduled entity (e.g., UE or child IAB node of the scheduling entity <NUM>) may identify the PSS collision upon receiving and processing PSS/SSS from both the scheduling entity <NUM> and the neighboring IAB node. As another example, a parent IAB node of the scheduling entity <NUM> or other IAB node in the IAB network may discover the PSS collision through network topology adaptation procedures, neighbor list <NUM> updates, neighbor cell searches, and/or other information provided by other nodes in the IAB network. In some examples, the PSS collision may result from a PCI collision between the scheduling entity <NUM> and the neighboring IAB node. In other examples, the PSS collision may result from different PCIs between the scheduling entity <NUM> and the neighboring IAB node producing the same PSS waveform. The PSS collision detection circuitry <NUM> may further be configured to execute PSS collision detection software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include PCI change management circuitry <NUM>, configured to perform a PCI change from the first PCI <NUM> to the second PCI <NUM>. In examples in which the scheduling entity <NUM> is an L2 relay IAB node experiencing a PSS collision, the PCI change management circuitry <NUM> may be configured to receive the message including the PCI change indication with the second PCI <NUM> from the IAB donor node. In examples in which the scheduling entity <NUM> is an RRC-enhanced IAB node experiencing a PCI collision, the PCI change management circuitry <NUM> may be configured to receive an indication of a PSS collision from the PSS collision detection circuitry <NUM> and operate together with the communication and processing circuitry <NUM> to generate and transmit a message including either the PCI change notification with the second PCI <NUM> or the PCI change request (e.g., requesting the second PCI <NUM>) to the IAB donor node in the IAB network. In this example, the PCI change management circuitry <NUM> may further be configured to receive the message including the PCI change indication with the second PCI <NUM> from the IAB donor node in response to the PCI change request. The PCI change management circuitry <NUM> may further be configured to execute PCI change management software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

<FIG> is a flow chart illustrating an exemplary process <NUM> for performing a PCI change based on a PSS waveform at a scheduling entity according to some aspects of the disclosure as claimed. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, within the scope of the claims, the process <NUM> is carried out by the scheduling entity illustrated in <FIG>. For example, the scheduling entity may include an L2 relay IAB node (e.g., a gNB or eNB) within an IAB network. In some examples, the process <NUM> may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block <NUM>, the scheduling entity communicates with a set of one or more scheduled entities (e.g., UEs and/or child IAB nodes) utilizing a first PCI associated with a cell served by the scheduling entity. For example, the resource assignment and scheduling circuitry <NUM> and communication and processing circuitry <NUM>, together with the transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to communicate with the set of scheduled entities.

At <NUM>, the scheduling entity changes from the first PCI to a second PCI to communicate with the set of one or more scheduled entities within the cell, where the first PCI corresponds to a first PSS waveform and the second PCI corresponds to a second PSS waveform different than the first PSS waveform. In some examples, the scheduling entity may receive a PCI change indication including the second PCI from a centralized network node (e.g., an IAB donor node central unit) in the IAB network to initiate the PCI change within the scheduling entity from the first PCI to the second PCI. The PCI change indication may be received in response to the IAB donor node detecting a PSS collision between the scheduling entity and a neighboring IAB node (e.g., between the first PSS waveform and a third PSS waveform transmitted by the neighboring IAB node, where the first PSS waveform and the third PSS waveform are identical). For example, the scheduling entity may be a first scheduling entity and the neighboring IAB node may be a second scheduling entity located proximate to the first scheduling entity. In this example, a first coverage area of the first scheduling entity may at least partially overlap a second coverage area of the second scheduling entity.

In some examples, within the scope of the claims, the scheduling entity detects a PSS collision with the second scheduling entity located proximate to the first scheduling entity (i.e., between the first PSS waveform and the third PSS waveform, wherein the first PSS waveform and the third PSS waveform are identical) and selects the second PCI to avoid collision with the third PSS waveform. In some examples, the scheduling entity may detect the PSS collision as a result of detecting a collision between the first PCI and a third PCI utilized by the second scheduling entity. Here, the first and third PCIs may be identical. The scheduling entity may then transmit a message including a PCI change notification with the second PCI to the IAB donor node upon changing to the second PCI.

In some examples, the scheduling entity may detect a PSS collision with the second scheduling entity (e.g., between the first PSS waveform and the third PSS waveform) and may transmit a PCI change request to the IAB donor node, requesting the second PCI. The scheduling entity may then receive the PCI change indication including the second PCI from the IAB donor node. For example, the PCI change management circuitry <NUM> shown and described above in connection with <FIG> may provide a means to change from the first PCI to the second PCI.

<FIG> is a flow chart illustrating another exemplary process <NUM> for performing a PCI change based on a PSS waveform at a scheduling entity according to some aspects of the disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process <NUM> may be carried out by the scheduling entity illustrated in <FIG>. For example, the scheduling entity may include an L2 relay IAB node (e.g., a gNB or eNB) within an IAB network. In some examples, the process <NUM> may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block <NUM>, the scheduling entity (e.g., a first scheduling entity) may communicate with a set of one or more scheduled entities (e.g., UEs and/or child IAB nodes) utilizing a first PCI associated with a cell served by the scheduling entity. For example, the resource assignment and scheduling circuitry <NUM> and communication and processing circuitry <NUM>, together with the transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to communicate with the set of scheduled entities.

At block <NUM>, the first scheduling entity may detect a collision between a first PSS waveform corresponding to the first PCI and a third PSS waveform transmitted by a second scheduling entity located proximate to the first scheduling entity. In this example, a first coverage area of the first scheduling entity may at least partially overlap a second coverage area of the second scheduling entity. In some examples, the first scheduling entity may detect a collision between the first PCI and a third PCI utilized by the second scheduling entity. In this example, the first PCI and the third PCI may be identical and the collision between the first PCI and the third PCI produces the collision between the first PSS waveform and the third PSS waveform. For example, the PSS collision detection circuitry <NUM> shown and described above in connection with <FIG> may provide a means for detecting the collision between the first PSS waveform and the third PSS waveform.

At block <NUM>, the first scheduling entity may select a second PCI corresponding to a second PSS waveform different than the first PSS waveform to avoid colliding with the third PSS waveform. For example, the PCI change management circuitry <NUM> shown and described above in connection with <FIG> may provide a means to select the second PCI.

At block <NUM>, the first scheduling entity may change from the first PCI to the second PCI to communicate with the set of one or more scheduled entities within the cell. For example, the PCI change management circuitry <NUM> shown and described above in connection with <FIG> may provide a means to change from the first PCI to the second PCI.

At block <NUM>, the first scheduling entity may then transmit a message including a PCI change notification with the second PCI to an IAB donor node upon changing to the second PCI. For example, the PCI change management circuitry <NUM>, together with the communication and processing circuitry <NUM>, resource assignment and scheduling circuitry <NUM>, and transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to transmit the PCI change notification to the IAB donor node.

At block <NUM>, the first scheduling entity may transmit a PCI change request to a centralized network node (e.g., IAB donor node) to request a second PCI corresponding to a second PSS waveform different than the first PSS waveform. For example, the PCI change management circuitry <NUM>, together with the communication and processing circuitry <NUM>, resource assignment and scheduling circuitry <NUM>, and transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to transmit the PCI change request.

At block <NUM>, the first scheduling entity may receive a PCI change indication including the second PCI from the centralized network node. For example, the PCI change management circuitry <NUM>, together with the communication and processing circuitry <NUM> and transceiver <NUM>, shown and described above in connection with <FIG> may provide a means for receiving the PCI change indication.

At block <NUM>, the scheduling entity (e.g., a first scheduling entity) may communicate with a set of one or more scheduled entities (e.g., UEs and/or child IAB nodes) utilizing a first PCI associated with a cell served by the scheduling entity. The first PCI may correspond to a first PSS waveform. For example, the resource assignment and scheduling circuitry <NUM> and communication and processing circuitry <NUM>, together with the transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to communicate with the set of scheduled entities.

At block <NUM>, the first scheduling entity may receive a PCI change indication including a second PCI corresponding to a second PSS waveform different from the first PSS waveform from a centralized network node. For example, the PCI change management circuitry <NUM>, together with the communication and processing circuitry <NUM> and transceiver <NUM>, shown and described above in connection with <FIG> may provide a means for receiving the PCI change indication.

In one configuration, the scheduling entity <NUM> includes means for performing the various functions and processes described in relation to <FIG>. In one aspect, the aforementioned means may be the processor <NUM> shown in <FIG> configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor <NUM> is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium <NUM>, or any other suitable apparatus or means described in any one of the <FIG>, <FIG>, and/or <NUM>-<NUM>, and utilizing, for example, the processes and/or algorithms described herein in relation to <FIG>.

<FIG> is a conceptual diagram illustrating an example of a hardware implementation for an exemplary centralized network node <NUM> employing a processing system <NUM>. For example, the centralized network node <NUM> maybe, for example, a base station (e.g., eNB, gNB), IAB donor node (e.g., CU of an IAB donor node), or any other centralized network node illustrated in any one or more of <FIG>, <FIG>, and/or <NUM>-<NUM>.

In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system <NUM> that includes one or more processors <NUM>. The processing system <NUM> may be substantially the same as the processing system <NUM> illustrated in <FIG>, including a bus interface <NUM>, a bus <NUM>, memory <NUM>, a processor <NUM>, and a computer-readable medium <NUM>. Furthermore, the centralized network node <NUM> may include an optional user interface <NUM> and a transceiver <NUM> substantially similar to those described above in <FIG>. That is, the processor <NUM>, as utilized in a centralized network node <NUM>, may be used to implement any one or more of the processes described below.

In some aspects of the disclosure, the processor <NUM> may include circuitry configured for various functions. For example, the processor <NUM> may include resource assignment and scheduling circuitry <NUM>, configured to, for example, schedule transmission of a message (e.g., RRC signal) including a PCI change indication to initiate a change from a first PCI <NUM> to a second PCI <NUM> at an L2 relay IAB node (e.g., a child IAB node) within the IAB network. The first PCI <NUM> and second PCI <NUM> may be stored, for example, in memory <NUM>. The resource assignment and scheduling circuitry <NUM> may further be configured to execute resource assignment and scheduling software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include communication and processing circuitry <NUM>, configured to communicate with a set of one or more scheduled entities (e.g., UEs or child IAB nodes). In some examples, the communication and processing circuitry <NUM> may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission). In examples in which the centralized network node, such as an IAB donor node, initiates the PCI change at an L2 relay IAB node (e.g., a child IAB node communicatively coupled to the IAB donor node through one or more backhaul links), the communication and processing circuitry <NUM> may be configured to generate and transmit, via the transceiver <NUM>, the message (e.g., RRC signal) to the L2 relay IAB node in the IAB network including the PCI change indication to initiate the PCI change from the first PCI <NUM> to the second PCI <NUM> within the L2 relay IAB node. The communication and processing circuitry <NUM> may further be configured to execute communication and processing software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include PSS collision detection circuitry <NUM>, configured to detect a PSS collision between two neighboring IAB nodes. For example, the PSS collision detection circuitry <NUM> may be configured to detect the PSS collision through topology adaptation procedures performed as a result of a mobile IAB node, neighbor list <NUM> updates (e.g., which may be stored, for example, in memory <NUM>) provided by L2 relay IAB nodes, and/or information provided by other network nodes (e.g., child IAB nodes and/or UEs). In some examples, the PSS collision may result from a PCI collision between the neighboring IAB nodes. In other examples, the PSS collision may result from different PCIs between the neighboring IAB nodes producing the same PSS waveform. The PSS collision detection circuitry <NUM> may further be configured to execute PSS collision detection software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

The processor <NUM> may further include PCI change management circuitry <NUM>, configured to perform a PCI change from the first PCI <NUM> to the second PCI <NUM>. For example, the PCI change management circuitry <NUM> may be configured to receive an indication of a PSS collision involving a child IAB node (e.g., an L2 relay IAB node communicatively coupled to the IAB donor node through one or more backhaul links) from the PSS collision detection circuitry <NUM>. The PCI change management circuitry <NUM> may further be configured to select the second PCI <NUM> for the child IAB node and initiate a PCI change within the child IAB node from the first PCI <NUM> to the second PCI <NUM>. For example, the PCI change management circuitry <NUM> maybe configured to operate together with the communication and processing circuitry <NUM> and transceiver <NUM> to generate and transmit the message including the PCI change indication with the second PCI <NUM> to the child IAB node experiencing the PSS collision.

In examples in which the child IAB node autonomously detects the PSS collision, the PCI change management circuitry <NUM> maybe configured to receive an indication of the PSS collision from the child IAB node. For example, the PCI change management circuitry <NUM> may be configured to receive a PCI change request from the child IAB node. The PCI change management circuitry <NUM> may then be configured to select the second PCI <NUM> for the child IAB node and generate and transmit a message including a PCI change indication with the second PCI <NUM> to the child IAB node experiencing the PSS collision.

In examples in which the child IAB node both autonomously detects the PSS collision and selects a new PCI (e.g., the second PCI <NUM>) for the child IAB node, the PCI change management circuitry <NUM> may be configured to receive a PCI change notification including the second PCI <NUM> from the scheduled entity and to update one or more neighbor lists(s) <NUM> with the second PCI <NUM>. The neighbor list(s) <NUM> may be stored, for example, in memory <NUM>, and may be provided to one or more IAB nodes within the IAB network via, for example, the communication and processing circuitry <NUM> and transceiver <NUM>. The PCI change management circuitry <NUM> may further be configured to execute PCI change management software <NUM> included on the computer-readable medium <NUM> to implement one or more functions described herein.

<FIG> is a flow chart illustrating an exemplary process <NUM> for performing a PCI change based on a PSS waveform at a centralized network node according to some aspects of the disclosure, as claimed. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, as claimed, the process <NUM> is carried out by the centralized network node illustrated in <FIG>. For example, the centralized network node may include an IAB donor node (e.g., IAB-CU) or other central entity within an IAB network. In some examples, the process <NUM> may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block <NUM>, the centralized network node detects a collision between a first PSS corresponding to a first PCI assigned to a first scheduling entity and a second PSS waveform corresponding to a second PCI assigned to a second scheduling entity located proximate to the first scheduling entity. Here, a first coverage area of the first scheduling entity and a second coverage area of the second scheduling entity may at least partially overlap. For example, the first and second scheduling entities may be L2 relay IAB nodes within an IAB network. In some examples, as claimed, the first PSS waveform and the second PSS waveform are identical. In some examples, the centralized network node may further detect a collision between the first PCI and the second PCI (e.g., the first and second PCI are identical), where the PCI collision produces the PSS collision. For example, the PSS collision detection circuitry <NUM> shown and described above in connection with <FIG> may provide a means to detect the PSS collision.

At block <NUM>, the centralized network node selects a third PCI for the first scheduling entity, where the third PCI corresponds to a third PSS waveform different than the first PSS waveform to avoid collision with the second PSS waveform. For example, the PCI change management circuitry <NUM> shown and described above in connection with <FIG> may provide a means to select the third PCI for the first scheduling entity.

At block <NUM>, the centralized network node transmits a PCI change indication including the third PCI to the first scheduling entity to initiate the PCI change within the first scheduling entity from the first PCI to the third PCI. For example, the PCI change management circuitry <NUM>, together with the communication and processing circuitry <NUM> and transceiver <NUM>, shown and described above in connection with <FIG> may provide a means to transmit the PCI change indication to the first scheduling entity.

In one configuration, as claimed, the centralized network node <NUM> includes means for performing the various functions and processes described in relation to <FIG>. In one aspect, the aforementioned means may be the processor <NUM> shown in <FIG> configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

The apparatus, devices, and/or components illustrated in <FIG>, <FIG>, <FIG>, and <FIG> may be configured to perform one or more of the methods, features, or steps described herein.

Claim 1:
A method (<NUM>) of wireless communication at a first scheduling entity, comprising:
communicating (<NUM>) with a set of one or more scheduled entities utilizing a first physical cell identifier, PCI;
wherein the first PCI corresponds to a first primary synchronization signal, PSS, waveform;
detecting a collision between the first PSS waveform and a third PSS waveform transmitted by a second scheduling entity located proximate to the first scheduling entity;
selecting a second PCI, wherein the second PCI corresponds to a second PSS waveform different than the first PSS waveform, to avoid colliding with the third PSS waveform,
wherein the first PSS waveform and the third PSS waveform are identical; and
changing (<NUM>) from the first PCI to the second PCI to communicate with the set of one or more scheduled entities.