The present application relates to wireless communication generally, and, in particular embodiments, to a system and method of synchronization channel design for radio access network (RAN) slicing.
New Radio (NR) has introduced slicing techniques to enable more efficient support of various services in the same network infrastructure. Slicing techniques can be applied in a core network (CN) and a RAN, respectively. The RAN provides wireless communication channels to user equipments (UEs), while the CN is typically comprised of nodes and functions making use of fixed links. In the RAN, radio access between a base station and a user equipment (UE) is wireless, while the backhaul connections of the RAN can be wired or wireless connections.
Services supported by RAN slicing can fall within a range of categories including, for example, enhanced mobile broadband (eMBB) communications (such as bi-directional video communications and streaming media content delivery); ultra-reliable and low latency communications (URLLC); and massive Machine Type Communications (mMTC). A RAN slice can be service specific. For instance, one RAN slice of a network may provide an eMBB service, another RAN slice of the network may provide a URLLC service, and yet another RAN slice of the network may provide an mMTC service.
A RAN slice may consist of one or more of the following components: one or more sets of transmit/receive nodes/points and user equipments (UEs); one or more sets of transmission schemes; one or more sets of time/frequency/beam/cell resources; mechanism of initial access procedures; mechanism of handover (HO) procedures; and one or more sets of state machines for managing UE states, such as the active state, the inactive (ECO) state, and the idle state. Currently, in a network with multiple RAN slices/services, only one synchronization channel (often called the default synchronization channel) is supported by the UE.
Technical advantages are generally achieved by embodiments of this disclosure which describe systems and methods of synchronization channel design for radio access network (RAN) slicing.
According to embodiments, a user equipment (UE) receives, from a first transmit point in a radio access network (RAN), a first synchronization signal over a first synchronization channel. The first synchronization channel is associated with a first RAN slice of a plurality of RAN slices in the RAN. The plurality of RAN slices comprise a second RAN slice associated with a second synchronization channel. The first synchronization channel and the second synchronization channel are different from a default synchronization channel of the first transmit point.
The UE performs a first synchronization procedure based on the first synchronization signal over the first synchronization channel, before the UE accesses a first service provided by the first RAN slice.
In some embodiments, before the UE receives the first synchronization signal over the first synchronization channel, the UE may receive a synchronization signal over the default synchronization channel. The plurality of RAN slices may comprise a default RAN slice associated with the default synchronization channel. The UE may perform a synchronization procedure based on the synchronization signal over the default synchronization channel before the UE accesses a default service provided by the default RAN slice. UE may receive configuration information of the first synchronization channel. The UE may then receive the first synchronization signal over the first synchronization channel associated with a first RAN slice.
In some embodiments, to receive the configuration information of the first synchronization channel, the UE may receive the configuration information of the first synchronization channel in one of a system information message, a radio resource control (RRC) message, or a slicing configuration message.
In some embodiments, the first synchronization channel may be transmitted on a first bandwidth part (BWP). The second synchronization channel may be transmitted on a second BWP. The second BWP may be different from the first BWP.
In some embodiments, the first synchronization channel may use a first time-frequency resource. The second synchronization channel may use a second time-frequency resource. The second time-frequency resource may be different from the first time-frequency resource. In some embodiments, the first time-frequency resource may at least partially overlap with the second time-frequency resource.
In some embodiments, the first synchronization channel may use a first beam resource. The second synchronization channel may use a second beam resource. The second beam resource may be different from the first beam resource. In some embodiments, the first beam resource may at least partially overlap with the second beam resource. In some embodiments, the first beam resource may be associated with one or more narrow beams. The second beam resource may be associated with one or more wide beams.
In some embodiments, the first synchronization channel may use a first synchronization sequence. The second synchronization channel uses a second synchronization sequence. The second synchronization sequence may be different from the first synchronization sequence. In one embodiment, the second synchronization sequence may be partially extracted from the first synchronization, and the first and the second synchronization sequences may transmit on the same symbol. In another embodiment, the first and the second synchronization sequences may have different lengths and transmit on the same symbol. In yet another embodiment, the first and the second synchronization sequences may have different lengths and transmit on the different symbols.
In some embodiments, the first RAN slice provides a first set of one or more services. The first set of one or more services may have a first quality of service (QoS) requirement. The second RAN slice may provide a second set of one or more services. The second set of one or more services may have a second QoS requirement. The second QoS requirement may be different from the first QoS requirement. In some embodiment, the second QoS requirement may have a higher latency or a higher reliability requirement than the first QoS requirement. Examples of a QoS requirement include at least one of a latency requirement, a jitter requirement, a packet ordering requirement, a dropped-packet rate, a throughput requirement, or an error rate.
In some embodiments, different synchronization channels for different RAN slices may use different synchronization signal block (SSB) configurations. For example, the first synchronization channel may use a first SSB configuration. The second synchronization channel may use a second SSB configuration different from the first SSB configuration. The first SSB configuration and the second SSB configuration may both be different from a default SSB configuration used by the default synchronization channel.
In some embodiments, the UE may receive, from a second transmit point in the RAN, a second synchronization signal over a second synchronization channel. The second transmit point may be the same as or different from the first transmit point. The second synchronization channel may be associated with the second RAN slice of the plurality of RAN slices in the RAN. The UE may then perform a second synchronization procedure based on the second synchronization signal over the second synchronization channel, before the UE accesses a second service provided by the second RAN slice. In one embodiment, the UE may not maintain synchronization on the default synchronization channel after performing the second synchronization procedure if the UE does not support the service on the default RAN slice associated with the default synchronization channel. In another embodiment, the UE may still maintain synchronization on the default synchronization channel after performing the second synchronization procedure if the UE still supports the service on the default RAN slice associated with the default synchronization channel.
In some embodiments, the UE may receive, from a third transmit point in the RAN, a third synchronization signal over a third synchronization channel. The third transmit point may be the same as or different from the second transmit point or the first transmit point. The third synchronization channel may be associated with the third RAN slice of the plurality of RAN slices in the RAN. The UE may then perform a third synchronization procedure based on the third synchronization signal over the third synchronization channel, before the UE accesses a third service provided by the third RAN slice. The third RAN slice may provide a third set of one or more services. The third set of one or more services may have a third QoS requirement different from the first and the second QoS requirement. In one embodiment, the UE may synchronize on the default synchronization channel, the first synchronization channel, and the second synchronization channel at the same time. The third synchronization channel may use a third SSB configuration different from the default SSB configuration, the first SSB configuration, and the second SSB configuration.
Apparatuses, as well as computer program products, for performing the methods are also provided.
The foregoing has outlined rather broadly the features of an embodiment of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of embodiments of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.
The making and using of embodiments of this disclosure are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.
In a conventional network system with multiple RAN slices/services, only one synchronization channel (often called a default synchronization channel) is supported by the UE. However, the current synchronization channel design in the conventional network system poses technical problems. Applications associated with different services have different service requirements, such as reliability and latency requirements. Using only one synchronization channel across multiple RAN slices/services does not accommodate well the specific service requirements (e.g., reliability and latency) of different RAN slices/services. To solve these technical problems, embodiments of this disclosure provide technical solutions that support multiple synchronization channels at the same time for multiple RAN slices/services of a RAN network. In doing so, the disclosed embodiment techniques described below provide more flexibility in synchronization for supporting multiple RAN slices/services in a network than the conventional systems, which in turn improve the resource utilization and performance of the network.
From the UE perspective, different UEs may support different sets of services and may need to access different RAN slices. Some UEs may only support one type of RAN slice/service, such as an mMTC service, or a URLLC service. Other UEs may support multiple types of services, such as supporting an eMBB service and a URLLC service. For a UE supporting multiple types of services, the UE may access to the network via a default RAN slice/service (e.g., eMBB) first. Later, the UE may be configured to access to a secondary RAN slice/service.
As described above, in conventional systems, a UE supports only one synchronization channel in a network with multiple RAN slices/services. This conventional synchronization channel presents a technical challenge because one synchronization channel does not adapt well different service requirements (e.g., reliability, latency requirements) associated with different RAN slices/services. In embodiments of this disclosure, different RAN slices/services can support different synchronization channels. The network can configure different SYNC sweeping patterns/cycles based on UE distributions of different RAN slices.
Supporting multiple synchronization channels for different RAN slices can satisfy different requirements of different services associated with the different RAN slices. Using completely different or partially different time/frequency/sequence resources for different synchronization channels can achieve such design goal. With multiple synchronization channels for different RAN slices, the synchronization procedure for the UE to synchronize and access to different RAN slices may take different approaches.
Some embodiments take the approach of a two-step synchronization procedure. For the first step of the two-step synchronization procedure, the UE may synchronize on a first link using the default synchronization channel (e.g., the NR Release-15 synchronization channel). Then, the UE may obtain the configuration information of a second synchronization channel (or a third, or a fourth synchronization channel, etc.) through one or more of the system information, the radio resource control (RRC) configuration, or the slicing/service configuration messages. For the second step of two-step synchronization procedure, if the UE has the capabilities and if the UE needs to access a particular RAN slice/service, the UE may be configured/enabled by the network to synchronize on a second link using the second synchronization channel (e.g., the synchronization channel 308 in
Some embodiments take the approach of a one-step synchronization procedure. In these embodiments, the UE may synchronize directly on a first link of a particular RAN slice using a particular synchronization channel. Here, the particular synchronization channel used by the UE for the one-step synchronization procedure is different from the default synchronization channel (e.g. the NR Release-15 synchronization channel). That is, accessing the default synchronization channel can be bypassed in some embodiments of the one-step synchronization procedure. For UEs that use the one-step synchronization procedure, these UEs may not support full capabilities for NR functions. For example, a UE may only support one of a narrowband-Internet of things (NB-IOT) service, a URLLC service, or an mMTC service.
At the operation 804, the UE performs a first synchronization procedure based on the first synchronization signal over the first synchronization channel, before the UE accesses a first service provided by the first RAN slice.
In some embodiments, before the UE receives the first synchronization signal over the first synchronization channel, the UE may receive a synchronization signal over the default synchronization channel. The plurality of RAN slices may comprise a default RAN slice associated with the default synchronization channel. The UE may perform a synchronization procedure based on the synchronization signal over the default synchronization channel before the UE accesses a default service provided by the default RAN slice. UE may receive configuration information of the first synchronization channel. The UE may then receive the first synchronization signal over the first synchronization channel associated with a first RAN slice as describe with the operation 802.
In some embodiments, to receive the configuration information of the first synchronization channel, the UE may receive the configuration information of the first synchronization channel in one of a system information message, a radio resource control (RRC) message, or a slicing configuration message.
In some embodiments, the first synchronization channel may be transmitted on a first bandwidth part (BWP). The second synchronization channel may be transmitted on a second BWP. The second BWP may be different from the first BWP.
In some embodiments, the first synchronization channel may use a first time-frequency resource. The second synchronization channel may use a second time-frequency resource. The second time-frequency resource may be different from the first time-frequency resource. In some embodiments, the first time-frequency resource may at least partially overlap with the second time-frequency resource.
In some embodiments, the first synchronization channel may use a first beam resource. The second synchronization channel may use a second beam resource. The second beam resource may be different from the first beam resource. In some embodiments, the first beam resource may at least partially overlap with the second beam resource. In some embodiments, the first beam resource may be associated with one or more narrow beams. The second beam resource may be associated with one or more wide beams.
In some embodiments, the first synchronization channel may use a first synchronization sequence. The second synchronization channel uses a second synchronization sequence. The second synchronization sequence may be different from the first synchronization sequence. In one embodiment, the second synchronization sequence may be partially extracted from the first synchronization, and the first and the second synchronization sequences may transmit on the same symbol. In another embodiment, the first and the second synchronization sequences may have different lengths and transmit on the same symbol. In yet another embodiment, the first and the second synchronization sequences may have different lengths and transmit on the different symbols.
In some embodiments, the first RAN slice provides a first set of one or more services. The first set of one or more services may have a first quality of service (QoS) requirement. The second RAN slice may provide a second set of one or more services. The second set of one or more services may have a second QoS requirement. The second QoS requirement may be different from the first QoS requirement. In some embodiment, the second QoS requirement may have a higher latency or a higher reliability requirement than the first QoS requirement. Examples of a QoS requirement include at least one of a latency requirement, a jitter requirement, a packet ordering requirement, a dropped-packet rate, a throughput requirement, or an error rate.
In some embodiments, different synchronization channels for different RAN slices may use different synchronization signal block (SSB) configurations. For example, the first synchronization channel may use a first SSB configuration. The second synchronization channel may use a second SSB configuration different from the first SSB configuration. The first SSB configuration and the second SSB configuration may both be different from a default SSB configuration used by the default synchronization channel.
In some embodiments, the UE may receive, from a second transmit point in the RAN, a second synchronization signal over a second synchronization channel. The second transmit point may be the same as or different from the first transmit point. The second synchronization channel may be associated with the second RAN slice of the plurality of RAN slices in the RAN. The UE may then perform a second synchronization procedure based on the second synchronization signal over the second synchronization channel, before the UE accesses a second service provided by the second RAN slice. In one embodiment, the UE may not maintain synchronization on the default synchronization channel after performing the second synchronization procedure if the UE does not support the service on the default RAN slice associated with the default synchronization channel. In another embodiment, the UE may still maintain synchronization on the default synchronization channel after performing the second synchronization procedure if the UE still supports the service on the default RAN slice associated with the default synchronization channel.
In some embodiments, the UE may receive, from a third transmit point in the RAN, a third synchronization signal over a third synchronization channel. The third transmit point may be the same as or different from the second transmit point or the first transmit point. The third synchronization channel may be associated with the third RAN slice of the plurality of RAN slices in the RAN. The UE may then perform a third synchronization procedure based on the third synchronization signal over the third synchronization channel, before the UE accesses a third service provided by the third RAN slice. The third RAN slice may provide a third set of one or more services. The third set of one or more services may have a third QoS requirement different from the first and the second QoS requirement. In one embodiment, the UE may synchronize on the default synchronization channel, the first synchronization channel, and the second synchronization channel at the same time. The third synchronization channel may use a third SSB configuration different from the default SSB configuration, the first SSB configuration, and the second SSB configuration.
In some embodiments, the processing system 900 is included in a network device that is accessing, or part otherwise of, a telecommunications network. In one example, the processing system 900 is in a network-side device in a wireless or wireline telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an applications server, or any other device in the telecommunications network. In other embodiments, the processing system 900 is in a user-side device accessing a wireless or wireline telecommunications network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet, a wearable communications device (e.g., a smartwatch, etc.), or any other device adapted to access a telecommunications network.
In some embodiments, one or more of the interfaces 910, 912, 914 connects the processing system 900 to a transceiver adapted to transmit and receive signaling over the telecommunications network.
The transceiver 1000 may transmit and receive signaling over any type of communications medium. In some embodiments, the transceiver 1000 transmits and receives signaling over a wireless medium. For example, the transceiver 1000 may be a wireless transceiver adapted to communicate in accordance with a wireless telecommunications protocol, such as a cellular protocol (e.g., long-term evolution (LTE), etc.), a wireless local area network (WLAN) protocol (e.g., Wi-Fi, etc.), or any other type of wireless protocol (e.g., Bluetooth, near field communication (NFC), etc.). In such embodiments, the network-side interface 1002 comprises one or more antenna/radiating elements. For example, the network-side interface 1002 may include a single antenna, multiple separate antennas, or a multi-antenna array configured for multi-layer communication, e.g., single input multiple output (SIMO), multiple input single output (MISO), multiple input multiple output (MIMO), etc. In other embodiments, the transceiver 1000 transmits and receives signaling over a wireline medium, e.g., twisted-pair cable, coaxial cable, optical fiber, etc. Specific processing systems and/or transceivers may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device.
It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a sending unit/module, a selecting unit/module, an assigning unit/module, an incrementing unit/module, a decrementing unit/module, and/or an accessing unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).
It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a sending unit/module, a selecting unit/module, an assigning unit/module, an incrementing unit/module, a decrementing unit/module, and/or an accessing unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).
Although this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.
In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.