Patent Description:
Demand for data traffic on wireless communications systems continues to increase. Wireless systems, such as fourth generation (<NUM>) wireless systems (e.g., the Long Term Evolution (LTE) system), or systems standardized by the 3rd Generation Partnership Project (3GPP) (e.g., the LTE-Advanced (LTE-A) system) are commercially widespread. Currently, next generation wireless systems are being developed. One such system, by the 3GPP, is a fifth generation (<NUM>) or New Radio (NR) wireless system.

The NR system, a first version of which was specified during 3GPP Release <NUM>, is a communication protocol which (in this first version) is generally directed to enhanced mobile broadband (eMBB) that allows for large frequency band allocations, high order modulations, and advanced multi-antenna solutions. Moreover, the concept of bandwidth part (BWP) is introduced in the NR specification. Bandwidth parts (BWPs) allow a network communications system that operates within a given bandwidth to assign subsets of that bandwidth for a given network-to-wireless device link.

The NR protocol specifies a single initial BWP per cell for initial access by a wireless device to a network node of the network communications system. That is, under the NR protocol there is one BWP that a wireless device can use for initial access to a given network node (e.g., a base station).

The publication <NPL> discloses discussions on synchronization raster in the unlicensed band, radio link monitoring in the unlicensed spectrum, and enhancement for <NUM>-step RACH. In detail, according to an option, multiple initial active uplink BWPs, refening to IAU, should be included in SIB1, and UE can perform LBT on them in parallel. Further, if multiple initial active uplink BWP candidates containing RACH resources are indicated in SIB1, it is up to UE to select one BWP out of them to transmit PRACH.

NR standardization is also undergoing deployments on unlicensed RF bands. While a single bandwidth part for initial access by a wireless device to a network node may be reasonable for a NR deployment in a licensed radio frequency(RF) band, this design imposes limitations for NR use in an unlicensed RF band. In an unlicensed RF band, usage can be shared with other systems. Thus, an initial BWP falling in an unlicensed RF band can be susceptible to interference from other systems sharing the unlicensed band, and to channel conditions that change frequently. Consequently, the likelihood for a successful initial access by a wireless device over an initial bandwidth part in an unlicensed RF band is reduced as compared to initial access performed in a licensed RF range.

As detailed herein, multiple initial bandwidth parts provided by network nodes for initial access to the network can improve the functioning of the network by allowing for spectrum diversity when operating in an unlicensed RF band where the absence of interference from other transmitters on the unlicensed band cannot be guaranteed.

Embodiments will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout.

Described below, in conjunction with the appended figures, are various embodiments of systems and methods for bandwidth part (BWP) flexibility for initial access to a wireless communications system over an unlicensed RF range. In accordance with an embodiment, a network node of a network communications system can configure and provide multiple initial bandwidth parts, which are smaller portions of a carrier, or total system bandwidth. The network node can provide the initial bandwidth parts for initial access to the network node by a wireless device. A wireless device can perform random access transmissions on one of the provided initial bandwidth parts.

<FIG> is a schematic diagram of an exemplary network communication system <NUM> for implementing the disclosed techniques. It will be appreciated that the illustrated communication system is representative and other systems may be used to implement the disclosed techniques. The exemplary network system <NUM> includes a network node <NUM> (also referred to as base station <NUM>) that operates in accordance with a cellular protocol, such as a protocol promulgated by 3GPP or another standard. For instance, the network system <NUM> may operate in accordance with LTE, LTE-A, or <NUM> NR standards. The cellular protocol or standard may be defined for and operate in an unlicensed spectrum (e.g., New Radio Unlicensed (NR-U)). However, it is to be appreciated that the techniques described herein can be applied to substantially any wireless communications system to enable BWP flexibility for initial access to the communications system.

The network communication system <NUM> of the illustrated example can support cellular-type protocols that may include circuit-switched network technologies and/or packet-switched network technologies. The network communication system <NUM> includes a base station <NUM> that services one or more electronic devices <NUM> (also referred to herein as user equipments (UEs), wireless communications devices, or wireless devices), designated as electronic devices 14a through 14n in <FIG>. The base station <NUM> may support communications between the electronic devices <NUM> and a network medium <NUM>.

Network medium <NUM> may facilitate communication between network node <NUM> to core network <NUM>. Core network <NUM> may include other base stations, electronic devices, servers, etc. For example, the core network may include a Mobility Management Entity (MME) node that acts as a main signaling node in an LTE Evolved Packet Core (EPC) architecture, or an Access and Mobility Management Function (AMF) node. Such nodes in the core network can serve wireless devices with Non Access Stratum (NAS) signaling functionality such as attachment and registration. Also, the core network can initiate paging of the electronic devices <NUM>, and can establish and configure data connections between electronic devices <NUM> and other core network components, or, e.g., devices on the internet.

The base station <NUM> may be an access point, an evolved NodeB (eNB) in a <NUM> network, a next generation NodeB (gNB) in a <NUM> or NR network, or another network node. As utilized herein, the term "base station" may refer, generally, to any device or network node that enables or facilitates radio communications (i.e., provides a radio interface) between the user devices and the network medium and network communication system. Base station <NUM> provides an interface to electronic devices <NUM>, or to other nodes in the network communications system <NUM>, to access services provided by core network <NUM>, such as attachment services, paging services, etc. Additionally, the term base station may refer to a transmission radio point (TRP) which may include all or parts of gNB functionality as described above. Accordingly, a base station includes the specific examples above and other supporting network nodes depending on the network implementation.

As noted, network communication system <NUM> may be, for example, a NR-based system. A carrier, or total system, bandwidth in NR systems may be wide (e.g. <NUM>). The total system bandwidth may be in a licensed or an unlicensed spectrum. The network communications system <NUM> may assign user devices to utilize a smaller portion (e.g., a sub-range) of bandwidth as compared to the total system bandwidth. The smaller portion may be referred to as a bandwidth part (BWP). In NR systems, for example, a bandwidth part consists of a group of contiguous physical resource blocks (PRBs). In accordance with an embodiment, network node <NUM> may provide multiple initial bandwidth parts any of which can be used by a wireless device to perform random access.

As used herein, an initial bandwidth part (also known as an initial uplink bandwidth part) refers to a bandwidth part used for random access by a wireless device. Random access refers to a procedure by which a wireless device initiates/establishes a UE-specific connection (e.g. prior to receiving or transmitting data) with a network node (e.g., a base station). Random access can occur in order to bring a wireless device from an idle state to a connected state. For example, a device that is not transferring data to a network node can perform random access in order to initiate data transfer with the network node. Additionally, random access can occur at handover of a connected wireless device from one network node to another network node. For example, a wireless device that is connected to a first network node can perform random access via a specified bandwidth part of a second network node as part of the handover from the first network node to the second network node.

In order to facilitate random access by a wireless device, a base station can periodically transmit/broadcast a synchronization signal block (SSB). The SSB may include synchronization signal elements such as the primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), the public broadcast channel (PBCH), and system information block <NUM> (SIB1). A wireless device attempting to initiate a data transfer with a network node receives synchronization signals available in the SSB. The wireless device can synchronize with the downlink channel by decoding the PSS and SSS. After synchronizing with the downlink channel, the wireless device is synchronized to the downlink frames.

After downlink synchronization, the wireless device can continue to receive and process additional parameters provided via the PBCH. Such additional information (referred to herein as control information) can include information on one or more initial bandwidth parts and the assigned resources for random access transmission (RACH resources) on these initial bandwidth parts. For example, the additional information can include system information block <NUM> (SIB1) which, in turn, can include information on one or more initial bandwidth parts and the assigned resources for random access transmission (RACH resources) on these initial bandwidth parts. Once the initial bandwidth part and RACH resources are determined, the wireless device can use the determined initial bandwidth part to transmit a random access preamble (RACH initiation).

In accordance with an embodiment, the base station <NUM> may provide a plurality of initial bandwidth parts, and may receive random access transmission from a wireless device <NUM> on any of the provided initial bandwidth parts. Additionally, base station <NUM> may perform wireless communications, and other functions of the base station <NUM>. For instance, the base station <NUM> may include a control circuit <NUM> that is responsible for overall operation of the base station <NUM>, including controlling the base station <NUM> to carry out the operations described in greater detail below. The control circuit <NUM> can include a processor <NUM> that executes code <NUM>, such as an operating system and/or other applications. The functions described in this disclosure document may be embodied as part of the code <NUM> or as part of other dedicated logical operations of the base station <NUM>. The logical functions and/or hardware of the base station <NUM> may be implemented in other manners depending on the nature and configuration of the base station <NUM>. Therefore, the illustrated and described approaches are just examples and other approaches may be used including, but not limited to, the control circuit <NUM> being implemented as, or including, hardware (e.g., a microprocessor, microcontroller, central processing unit (CPU), etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an application-specific integrated circuit (ASIC), etc.).

The code <NUM> and any stored data (e.g., data associated with the operation of the base station <NUM>) may be stored on a memory <NUM>. The code may be embodied in the form of executable logic routines (e.g., a software program) that are stored as a computer program product on a non-transitory computer readable medium (e.g., the memory <NUM>) of the base station <NUM> and is executed by the processor <NUM>. The functions described as being carried out by the base station <NUM> may be thought of as methods that are carried out by the base station <NUM>.

The memory <NUM> may be, for example, one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, the memory <NUM> includes a non-volatile memory for long term data storage and a volatile memory that functions as system memory for the control circuit <NUM>. The memory <NUM> is considered a non-transitory computer readable medium.

The base station <NUM> includes communications circuitry that enables the base station <NUM> to establish various communication connections. For instance, the base station <NUM> may have a network communication interface <NUM> to communicate with the network medium <NUM>. Also, the base station <NUM> may have a wireless interface <NUM> over which wireless communications are conducted with the electronic devices <NUM>, including the dynamic bandwidth allocations described herein. The wireless interface <NUM> may include a radio circuit having one or more radio frequency transceivers (also referred to as a modem), at least one antenna assembly, and any appropriate tuners, impedance matching circuits, and any other components needed for the various supported frequency bands and radio access technologies.

The electronic devices <NUM> serviced by the base station <NUM> may be user devices, also known as user equipments or UEs, wireless communications devices, or machine-type devices. Exemplary electronic devices <NUM> include, but are not limited to, mobile radiotelephones ( such as "smartphones"), tablet computing devices, computers, a device that uses machine-type communications, machine-to-machine (M2M) communications or device-to-device (D2D) communication (e.g., a sensor, a machine controller, an appliance, etc.), a camera, a media player, or any other device that conducts wireless communications with the base station <NUM>. Such devices are referred to herein, generally, as wireless devices.

As shown in <FIG>, each electronic device <NUM> may include operational components for carrying out the wireless communications, the bandwidth part flexibility described herein, and other functions of the electronic device <NUM>. For instance, among other components, each electronic device <NUM> may include a control circuit <NUM> that is responsible for overall operation of the electronic device <NUM>, including controlling the electronic device <NUM> to carry out the operations described in greater detail below. The control circuit <NUM> includes a processor <NUM> that executes code <NUM>, such as an operating system and/or other applications. The functions described in this disclosure document may be embodied as part of the code <NUM> or as part of other dedicated logical operations of the electronic device <NUM>. The logical functions and/or hardware of the electronic device <NUM> may be implemented in other manners depending on the nature and configuration of the electronic device <NUM>. Therefore, the illustrated and described approaches are just examples and other approaches may be used including, but not limited to, the control circuit <NUM> being implemented as, or including, hardware (e.g., a microprocessor, microcontroller, central processing unit (CPU), etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an application-specific integrated circuit (ASIC), etc.).

The code <NUM> and any stored data (e.g., data associated with the operation of the electronic device <NUM>) may be stored on a memory <NUM>. The code <NUM> may be embodied in the form of executable logic routines (e.g., a software program) that is stored as a computer program product on a non-transitory computer readable medium (e.g., the memory <NUM>) of the electronic device <NUM> and is executed by the processor <NUM>. The functions described as being carried out by the electronic device <NUM> may be thought of as methods that are carried out by the electronic device <NUM>.

The electronic device <NUM> includes communications circuitry that enables the electronic device <NUM> to establish various communication connections. For instance, the electronic device <NUM> may have a wireless interface <NUM> over which wireless communications are conducted with the base station <NUM>, including the bandwidth part flexibility and random access procedures described herein. The wireless interface <NUM> may include a radio circuit having one or more radio frequency transceivers (also referred to as a modem), at least one antenna assembly, and any appropriate tuners, impedance matching circuits, and any other components needed for the various supported frequency bands and radio access technologies.

Other components of the electronic device <NUM> may include, but are not limited to, user inputs (e.g., buttons, keypads, touch surfaces, etc.), a display, a microphone, a speaker, a camera, a sensor, a jack or electrical connector, a rechargeable battery and power supply unit, a SIM card, a motion sensor (e.g., accelerometer or gyro), a GPS receiver, and any other appropriate components.

The network communication system <NUM> can utilize multiple initial bandwidth parts to improve the performance of initial access by a wireless device to a network node over unlicensed RF bands used by a NR system. This improved performance can be implemented and realized from a wireless device in an idle mode initiating contact with the network communication system, and during handovers of a wireless device between network nodes.

With reference to <FIG>, an exemplary schematic diagram of multiple initial bandwidth parts per node/cell of a network communications system is illustrated. As shown in <FIG>, a total system bandwidth <NUM> of a network communications system, which may be an unlicensed RF band, can be segmented into multiple subsections or portions referred to herein as bandwidth parts.

Transmissions, including broadcasts, from node <NUM> can define a first cell <NUM> within the network communications system. Likewise, transmissions, including broadcasts, from node <NUM> can define a second cell <NUM> within the network communications system. Portions of total system bandwidth <NUM> can be allocated among the different nodes/cells of the network communications system. For example, bandwidth allocation <NUM>, which is a portion of total system bandwidth <NUM>, can be allocated to node <NUM> for use in cell <NUM>. Likewise, bandwidth allocation <NUM>, which is also a portion of total system bandwidth <NUM> (in this example, a distinct portion), can be allocated to node <NUM> for use in cell <NUM>.

<FIG> illustrates an example where node <NUM> and node <NUM> are allocated separate non-overlapping bandwidth allocations (<NUM> and <NUM>). Other embodiments are possible where, e.g., multiple cells use overlapping bandwidth allocations. As one example <NUM> and <NUM> may be the same frequency allocations. As another example <NUM> and/or <NUM> may be allocated to use the complete system bandwidth <NUM>.

Bandwidth allocated among nodes/cells of a network communications system can be further segmented into bandwidth parts. As additionally shown in <FIG>, bandwidth allocation <NUM> is further segmented into bandwidth parts <NUM>-<NUM>. Bandwidth allocation <NUM> is further segmented into bandwidth parts <NUM>-<NUM>. The number of bandwidth parts shown in <FIG> is exemplary, and more or less bandwidth parts than the number shown in <FIG> can be configured for a given node/cell. Further, different bandwidth part configurations (not shown in <FIG>) are possible, e.g. where different bandwidth parts are overlapping in frequency. As one example, a first bandwidth part for a bandwidth allocation may comprise a full total system bandwidth, while another bandwidth part may consist of a subset of the first bandwidth part. Also, it is not required that there are configured bandwidth parts for the whole system bandwidth nor for the whole bandwidth allocation for a separate cell. For example, an initial bandwidth part may be a smaller subset of another bandwidth part. According to an exemplary embodiment, total system bandwidth <NUM> may be <NUM> for NR systems and may be an unlicensed RF band. Bandwidth parts <NUM>-<NUM> may be on the order of hundreds of megahertz.

In accordance with an embodiment, multiple bandwidth parts allocated to each node/cell can be configured as initial bandwidth parts. As shown in <FIG>, BWPs <NUM> and <NUM> can be configured as initial BWPs provided by node <NUM>. Electronic device <NUM> is shown camping in cell <NUM>. In a scenario where electronic device <NUM> is initiating access with node <NUM>, electronic device <NUM> can receive control information, including SIB1, that is broadcast from node <NUM>. SIB1 can include information pertaining to each of the multiple initial bandwidth parts provided by node <NUM> (i.e., initial bandwidth parts <NUM> and <NUM>), and the assigned resources for random access transmission (RACH resources) on each initial bandwidth part provided by node <NUM>. Electronic device <NUM> can transmit a random access preamble (RACH initiation) on either initial bandwidth part <NUM> or initial bandwidth part <NUM> to initiate uplink communication with node <NUM>.

The ability to perform random access on either initial bandwidth part <NUM> or <NUM> allows for spectrum diversity when, e.g., operating in an unlicensed RF band. That is, multiple initial bandwidth parts allow for random access on the bandwidth part having less interference, channel occupancy, etc., and therefore a greater chance of successful random access by a wireless device.

Each of <FIG> is a signaling diagram, or a flow-diagram, of exemplary embodiments of the present invention. Although illustrated in a logical progression, the illustrated blocks and/or signaling steps of these figures may be carried out in other orders and/or with concurrence between two or more blocks/steps. Therefore, the illustrated diagram may be altered (including omitting steps), and steps from one figure may be used with steps from other figures to form different embodiments.

<FIG> is a signaling diagram of a wireless device in idle mode. <FIG> includes wireless device <NUM> and network node <NUM>. As illustrated, wireless device <NUM> begins in idle mode <NUM>. That is, wireless device <NUM> is not connected to, and not transferring data with, any network node. At block <NUM>, the network node <NUM> can configure and/or provide multiple initial bandwidth parts over which random access transmission may be performed by wireless device <NUM>. At step <NUM>, network node <NUM> can broadcast control information, including SIB <NUM>. At step <NUM>, the control information is received by wireless device <NUM>. An initial bandwidth part for random access transmission is determined by the wireless device at step <NUM>. At step <NUM>, wireless device <NUM> performs random access transmission on the determined initial bandwidth part.

In accordance with an embodiment, multiple initial bandwidth parts can also be provided for random access in a handover scenario where a wireless device is being handed over from one network node to another network node. Referring again to <FIG>, a handover scenario is illustrated where electronic device <NUM> is handed over from node <NUM> to node <NUM>, in accordance with an embodiment.

BWPs <NUM> and <NUM> can be configured as initial BWPs provided by node <NUM>. Electronic device <NUM> may be in a connected mode, and may be connected to node <NUM>. While connected to node <NUM>, electronic device <NUM> can evaluate control information, including SIB1, that is broadcast from node <NUM>. The control information (including SIB1) broadcast by node <NUM> can include information on each of the multiple initial bandwidth parts provided by node <NUM> (i.e., initial bandwidth parts <NUM> and <NUM>) ), and the assigned resources for random access transmission (RACH resources, e.g., random access preamble transmission) on each initial bandwidth part provided by node <NUM>. Electronic device <NUM> can relay these evaluations of the control information of node <NUM> back to node <NUM> and the network communication system.

Based on the relayed evaluations of the control information, the network communication system (e.g., network communication system <NUM>), can determine that a handover to node <NUM> is appropriate. Electronic device <NUM> may then receive a handover command from the network communication system, via node <NUM>, indicating that electronic device <NUM> is to be handed over to node <NUM>. In response to the handover command, electronic device <NUM> can attempt to initiate contact with node <NUM>. Electronic device <NUM> can transmit a random access preamble (RACH initiation) on either initial bandwidth part <NUM> or initial bandwidth part <NUM> to initiate uplink communication with node <NUM>. Once uplink communication is established on either initial bandwidth part <NUM> or initial bandwidth part <NUM>, the handover to node <NUM>/cell <NUM> can proceed.

<FIG> is a signaling diagram of an exemplary handover procedure, in accordance with an embodiment. <FIG> includes wireless device <NUM>, network node <NUM>, and network node <NUM>. <FIG> also includes core network <NUM>. Network node <NUM> and network node <NUM> are connected to core network <NUM> vie network medium <NUM> and network medium <NUM>, respectively. Network node <NUM> represents a serving node. Wireless device <NUM> is in a connected mode and connected <NUM> to network node <NUM>.

At block <NUM>, network node <NUM> provides multiple initial bandwidth parts for random access. The multiple initial bandwidth parts <NUM> may be defined by components of core network <NUM>. Core network <NUM> may be configured by components of core network <NUM> to provide multiple initial bandwidth parts <NUM>.

Network node <NUM> can send a command signal <NUM> to wireless device <NUM> that configures wireless device <NUM> to perform candidate node/cell measurements on neighboring nodes/cells. This command signal can include which neighboring cells to perform candidate cell measurements on. For example, in the illustrated embodiment, the command signal <NUM> can include instructions to perform candidate cell measurements on network node <NUM> and its corresponding cell.

In accordance with an embodiment, network node <NUM> is aware of the multiple initial bandwidth parts configured for, and provided by, network node <NUM>. For example, network node <NUM> may be aware of the multiple initial bandwidth parts configured for network node <NUM> via communications with core network <NUM>. In such an embodiment, network node <NUM> may provide wireless device <NUM> with indications of the multiple initial bandwidth parts configured for network node <NUM> in the command signal <NUM>. In this scenario, wireless device <NUM> will be aware of the multiple initial bandwidth parts provided by network node <NUM> prior to analyzing control information from network node <NUM>.

Network node <NUM> can periodically broadcast synchronization signals available in the SSB, including control information. The broadcast control information can include information on one or more initial bandwidth parts provided by network node <NUM> and the assigned resources for random access transmission (RACH resources) on these initial bandwidth parts. At step <NUM>, network node <NUM> can broadcast SSB and control information and wireless device <NUM> can receive the broadcast control information. In an embodiment where network node <NUM> is not aware of the multiple initial bandwidth parts provided by network node <NUM>, or where the multiple initial bandwidth parts provided by network node <NUM> are not indicated in the command signal <NUM>, wireless device <NUM> can determine the multiple initial bandwidth parts provided by network node <NUM> from the broadcast control information <NUM>.

In accordance with an embodiment, at block <NUM>, wireless device <NUM> determines - either based on command signal <NUM> (embodiment not covered by the present claims) or the broadcast control information <NUM>-the multiple initial bandwidth parts provided by network node <NUM>. Wireless device <NUM> performs candidate cell measurement at block <NUM>, e.g., on each determined initial bandwidth part. At step <NUM>, wireless device <NUM> reports the measurements to network node <NUM>. At block <NUM>, based on the reported measurements <NUM>, network node <NUM> determines that a trigger condition has been met, the trigger condition indicating that a handover of wireless device <NUM> to network node <NUM> is appropriate. In response to the determination that the trigger condition has been met, network node <NUM> sends a handover command signal <NUM> to wireless device <NUM>. At step <NUM> wireless device <NUM> performs random access transmission on one of the initial bandwidth parts provided by network node <NUM>. At step <NUM>, the handover procedure between wireless device <NUM> and network node <NUM> is continued.

In an exemplary embodiment, the network communication system can provide regular network condition information indicative of signal quality on one or more of the multiple initial bandwidth parts. The network condition information can include indications of measured channel occupancy, historical access probability (e.g., a listen-before-talk (LBT) success ratio) and/or similar indications of an initial BWP's signal quality.

The network communications system can use the network condition information to determine a preferred initial bandwidth part for random access by a wireless device. Alternatively, the network communications system can provide the wireless device with the network condition information in order to enable the wireless device to determine, based at least partially on the provided network condition information, a preferred initial bandwidth part for random access by a wireless device.

<FIG> is a flow-diagram of a representative method of determining an initial bandwidth part for random access transmission based on network condition information, in accordance with an embodiment not covered by the present claims. At step <NUM>, network condition information is determined for multiple initial bandwidth parts provided by a network node. For example, a network node can measure channel occupancy, historical access probability (e.g., a listen-before-talk (LBT) success ratio) and/or similar indications of an initial BWP's signal quality.

At step <NUM> (an optional step indicated by the broken lines enclosing the step), the determined network condition information is provided to a wireless device, e.g., via control information transmitted from a network node. At step <NUM>, an initial bandwidth part on which to perform random access can be determined based on the provided network condition information. In one embodiment, step <NUM> can be performed, e.g., by the network node that provided the network condition information. In an embodiment that includes step <NUM>, the wireless device that received the network condition information may determine the preferred initial bandwidth part based on the network condition information. At step <NUM>, random access can be performed on the determined initial bandwidth part by the wireless device.

Network condition information for the initial BWPs of a node/cell that a wireless device is attempting to initiate communication with, e.g., from an idle state, may be provided to a wireless device in the synchronization blocks, e.g., in SIB1. Thus, with additional reference to <FIG>, network condition information may be provided via broadcast control information <NUM> from node <NUM>. In accordance with an embodiment, network condition information for the initial BWPs of inter/intra frequency neighbor nodes/cells (i.e. a candidate node/sell) may also be provided via broadcast control information <NUM> from node <NUM>. For instance, network condition information for the initial BWPs of candidate cells may be transmitted in SIB3 or SIB4, which may be included in synchronization blocks.

Additionally, network condition information regarding multiple bandwidth parts of a candidate cell can be provided to a wireless device during the hand-off procedure to the candidate cell. In one embodiment (referring now to <FIG>), serving/connected node <NUM> may provide network condition information via the command signal <NUM> to wireless device <NUM>. Alternatively, network node <NUM> may provide network information in broadcast control information <NUM> (as noted above, e.g., in SIB3 or SIB4).

In accordance with an exemplary embodiment, a wireless device can perform measurements on initial bandwidth parts provided via synchronization signals from a base station to determine the downlink signal quality experienced by the wireless device on each of the measured initial bandwidth parts. Such measurements may be performed by the wireless device on the regularly network-transmitted synchronization signal bursts. The frequency-dependent channel conditions and the interference on a bandwidth part in an unlicensed band can differ. Thus, in an exemplary embodiment, the wireless device may consider these measurements when determining which initial BWP to perform random access transmission on. By considering such measurements of the provided initial bandwidth parts, the wireless device can determine the initial bandwidth part having the most favorable channel conditions and/or the least amount of interference on which to perform random access.

<FIG> is a flow-diagram of a representative method of determining an initial bandwidth part for random access transmission based on measurements of initial bandwidth parts, in accordance with an embodiment not falling under the scope of protection of the present claims. At step <NUM>, measurements can be performed by a wireless device on multiple initial bandwidth parts provided by a network node. At step <NUM>, a preferred initial bandwidth part on which to perform random access is determined from among the multiple received initial bandwidth parts. The determination of step <NUM> is based, at least partially, on the performed measurements. At step <NUM>, random access transmission is performed on the determined initial bandwidth part.

A wireless device preparing for a handover may evaluate, via measurements (as discussed above), the two or more initial BWPs provided on the node/cell being considered for handover (i.e., the candidate node/cell to which the wireless device will be handed over). The wireless device can report the measurements of the initial BWPs provided by the candidate node/cell to the node of the active or currently-servicing cell in a measurement report. Such an evaluation/report of the provided initial bandwidth parts of a handover candidate cell is referred to herein as a candidate cell measurement/candidate cell measurement report.

In accordance with an embodiment, a candidate cell measurement/report may include measurements indicative of signal strength and signal quality. Additionally, the candidate cell measurement/report may include channel sensing information for the initial BWPs (e.g. channel occupancy or other sensing metrics that measure the current usage of the measured frequency). The candidate cell measurement/report may also include a preference indicator indicative of a preferred initial BWP based on the measurements taken by the wireless device. The preference indicator can indicate an initial BWP of the multiple initial bandwidth parts having a good probability for a successful random access transmission based on the candidate cell measurement. A wireless device may uses the bandwidth part indicated by the preference indicator for random access.

Alternatively, the wireless device can report the channel sensing information and/or the preference indicator to the servicing network node, which may then issue a handover command to the wireless device that specifies a particular one of the multiple initial bandwidth parts provided by the candidate network node for random access in the handover procedure. The specified particular one of the multiple initial bandwidth parts can be determined by the network communication system based on the reported channel sensing information or the reported preference indicator.

<FIG> is a flow-diagram of a representative method of determining an initial bandwidth part for random access transmission based on measurements of initial bandwidth parts, in accordance with an embodiment not falling under the scope of protection of the present claims. At step <NUM>, a wireless device can perform measurements on multiple initial bandwidth parts provided by a network node. At step <NUM>, the wireless device can determine channel sensing information based on the performed measurements. At step <NUM>, the wireless device can determine a preferred initial bandwidth part based on the performed measurements. The wireless device can report the channel sensing information and the preferred initial bandwidth part to the servicing network node at steps <NUM> and <NUM>, respectively. At step <NUM>, the wireless device can receive a handover command specifying an initial bandwidth part for random access based on the reported channel sensing information or the reported preferred initial bandwidth part.

In accordance with an embodiment, a wireless device can be configured with measurement trigger conditions. The trigger conditions, when met, can indicate acceptable parameters for a handover of a wireless device from one node/cell to another node/cell. The measurement trigger conditions may be defined and relayed to the wireless device via the network communications system, for example, by/via a network node.

A wireless device that performs candidate cell measurement can report a measurement trigger event. Upon detecting that a measurement trigger event has occurred a wireless device can report to the network communication system that a measurement trigger condition has been met. The report may be merely an indication that a defined measurement trigger has been met, or the report may include a value of a measured attribute that is in excess of a threshold value defined for the attribute. Exemplary attributes include signal strength, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), signal-to-noise ratio (SINR), channel occupancy, etc..

A wireless device can perform multiple channel sensing procedures on one or more of the initial BWPs provided by a candidate cell (e.g., sensing procedures the wireless device would perform in an attempt to access a given channel). The wireless device can report a measurement trigger event to the servicing network node when/if the channel sensing procedure success rate is higher than a threshold. The threshold may be defined by the network communication system (e.g., the core network depicted in <FIG>).

The communications network (e.g., a network node) may transmit a handover command to a wireless device based on a reported measurement trigger event or reported measurements of the provided initial BWPs of a candidate node/cell.

<FIG> is a flow-diagram of a representative method of generating a handover command based on a measurement condition, in accordance with an embodiment not falling under the scope of protection of the present claims.

At step <NUM> a wireless device can perform measurements on multiple initial bandwidth parts provided by a network node. At step <NUM>, the wireless device can determine, based on the performed measurements, that a measurement trigger condition has been met on one of the multiple initial bandwidth parts provided by the network node. The wireless device can report that the trigger condition has been met to the servicing node at step <NUM>. At step <NUM>, the wireless device can receive a handover command from servicing base station based on measurement trigger condition. The received handover command can include an indication of a preferred initial bandwidth part provided by the candidate network node for random access, which can be the initial bandwidth part for which the measurement trigger condition was met.

In yet another embodiment, the communications network can use reported measurements of the provided initial BWPs of multiple candidate nodes/cells to transmit a conditional handover command message to a wireless device, including multiple initial BWPs on multiple candidate nodes/cells that are acceptable for a handover. Upon receipt of such a conditional handover command message, the wireless device can determine a preferred initial bandwidth part from the multiple initial BWPs indicated in the conditional handover command message based on a measurement trigger condition being met. The wireless device can then perform random access transmission on the preferred initial bandwidth part.

<FIG> is a flow-diagram of a representative method of determining a preferred initial bandwidth part based on a conditional handover command, in accordance with an embodiment not falling under the scope of protection of the present claims. At step <NUM>, a wireless device can perform measurements on multiple initial bandwidth parts provided by a candidate network node. At step <NUM>, the wireless device can receive a conditional handover command from a servicing network node. At step <NUM>, the wireless device can determine, based on the performed measurements, a preferred initial bandwidth part provided by the candidate network node on which to perform random access. At step <NUM>, the wireless device can perform random access on the determined preferred initial bandwidth part.

In exemplary embodiments, measurements performed by a wireless device, such as those described, e.g., in <FIG>, can be considered along with network condition information provided by the network communication system (described above) when a preferred initial bandwidth part is being determined. A determination based on both wireless device measurements and network condition information can be performed by either the wireless device or a network node.

In accordance with an embodiment, the network communication system (e.g., a network node) can send a paging message to a wireless device. The paging message can initiate/trigger the random access procedure. In such an embodiment, the paging signal may include information indicative of which of the available initial BWPs the network communications system has determined is a preferred (i.e., a most suitable) initial bandwidth part for random access. Such a determination can be based on, e.g., network condition information as determined by a network node (as discussed above), wireless device measurements of the provided initial bandwidth parts, (also as discussed above), or a combination of these two features.

In accordance with an embodiment, network nodes can specify, in the paging method, a mandatory initial bandwidth part on which a wireless device is required to perform random access transmission. A wireless device can also be configured to view the initial bandwidth part specified or indicated in the received paging message as a mandatory initial bandwidth part. In such an embodiment, the wireless device does not determine one of the multiple initial bandwidth parts on which to perform random access procedures, but instead performs random access on whichever of the multiple initial bandwidth parts is indicated/specified in the paging message. In such an embodiment, the network node may only specify or indicate one of the multiple bandwidth parts provided by the network node in the paging message. In this way, a wireless device that is not configured to determine a preferred initial bandwidth part from the plurality of initial bandwidth parts can still take advantage of multiple initial bandwidth parts.

<FIG> is a flow-diagram of a representative method of determining an initial bandwidth part for random access transmission based on a paging method, in accordance with an embodiment not falling under the scope of protection of the present claims. A paging method can be provided to a wireless device at step <NUM>. The paging method can include an indication of a preferred bandwidth part of multiple initial bandwidth parts provided by a network node. In response to the paging method, the wireless device can perform random access on the indicated initial bandwidth part at step <NUM>.

As noted above, a network node of the communications network can offer more than one initial bandwidth part for random access by a wireless device initiating contact with the network node during a handover procedure from another network node. In accordance with an embodiment, a handover procedure can include an evaluation by a wireless device of the multiple initial BWPs provided by the network node servicing the cell to which a wireless device is to be handed over. Based on the evaluation, the wireless device can determine the provided initial BWP that indicates a good probability for a successful random access transmission with respect to channel access over the (e.g., unlicensed) band of the provided initial bandwidth parts.

Claim 1:
A method performed by a network node (<NUM>) for providing access to a wireless communications system (<NUM>), wherein a carrier/system bandwidth (<NUM>) of the wireless communications system (<NUM>) comprises a set of bandwidth parts (<NUM>, <NUM>, <NUM>) and the network node is configured with a plurality of initial bandwidth parts (<NUM>, <NUM>) selected from the set of bandwidth parts (<NUM>, <NUM>, <NUM>) for initial network access on an unlicensed spectrum, the method comprising:
broadcasting control information (<NUM>), wherein the control information is indicative of the plurality of initial bandwidth parts (<NUM>, <NUM>);
receiving a random access transmission (<NUM>) from a wireless device (<NUM>) on one initial bandwidth part of the plurality of initial bandwidth parts (<NUM>, <NUM>)
indicating, in the control information (<NUM>), a second plurality of initial bandwidth parts (<NUM>, <NUM>) provided by a second network node (<NUM>);
receiving a candidate cell measurement report (<NUM>) from the wireless device that reports measurements (<NUM>, <NUM>) of the second plurality of initial bandwidth parts (<NUM>, <NUM>) provided by the second network node (<NUM>); and
transmitting a handover command (<NUM>, <NUM>) based on the received candidate cell measurement report;
wherein the cell measurement report (<NUM>) includes a measurement trigger event (<NUM>),
wherein the measurement trigger event indicates that at least one initial bandwidth part of the second plurality of initial bandwidth parts (<NUM>, <NUM>) provided by the second network node (<NUM>) has met a measurement trigger condition (<NUM>), and
wherein the handover command (<NUM>, <NUM>, <NUM>) prompts random access (<NUM>) between the wireless device and the second network node on one initial bandwidth part of the second plurality of initial bandwidth parts (<NUM>, <NUM>).