CN115589793A

CN115589793A - Small data transmission

Info

Publication number: CN115589793A
Application number: CN202180006614.9A
Authority: CN
Inventors: D·拉塞尔瓦; M·玛特尼亚; N·M·基拉里奇普拉塔斯; 吴春丽; K·M·兰塔-阿霍
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2023-01-10
Also published as: WO2022233005A1

Abstract

Apparatus and methods for handling small data transmissions are disclosed. The device obtains information indicating association of random access resources with at least one synchronization signal block and information associating pre-configured resources with the indicated random access resources. Determining an occasion for small data transmission associated with at least one synchronization signal block based on information associating the pre-configured resource with the indicated random access resource.

Description

Small data transmission

Technical Field

The present disclosure relates to methods, apparatuses, and computer program products for small data transmission in a communication system.

Background

Data may be communicated between two or more communication devices (e.g., user or terminal devices, base stations/access points, and/or other nodes). For example, communication may be provided over a communication network and one or more compatible communication devices. The communication device on the network side provides an access point for the system and is provided with appropriate signal receiving and transmitting means to enable communication, for example to enable other devices to access the communication system. The communication may include, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text messages, multimedia and/or content data, and so forth. Non-limiting examples of services provided include two-way or multi-way calls, data communications, multimedia services, and access to data network systems such as the internet. Small data and/or data transmissions may also be communicated.

In a mobile or wireless communication system, at least a portion of the data communication between at least two devices occurs over a wireless or radio link. Examples of wireless systems include Public Land Mobile Networks (PLMNs), satellite-based communication systems, and different wireless local area networks, such as Wireless Local Area Networks (WLANs). A broader communication system through appropriate communication devices or terminals. Such devices may be referred to as User Equipment (UE).

The communication device is provided with suitable signal receiving and transmitting means for enabling communication, e.g. for enabling access to a communication network or for communicating directly with other users. A user's communication device may access a carrier provided by a station (e.g., a base station) at a radio access network and transmit and/or receive communications on the carrier. Multiple carriers may be provided, e.g., by beams. The beams may be formed by analog, digital, or hybrid beamforming.

A communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters for the connection are also typically defined. An example of a communication system is UTRAN (3G radio). Other examples of communication systems are the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology and the so-called fifth generation (5G) or new air interface (NR) networks. The third generation partnership project (3 GPP) is standardizing 5G. A subsequent version of the standard is called release (Rel).

A device in an inactive state may require a small and infrequent data transmission. A Radio Resource Control (RRC) connection recovery is performed to switch to an RRC connected state to enable transmission of small data. After the data transfer, the connection is then suspended and returned to the inactive state. Switching between states may result in unnecessary power consumption, signaling overhead, and/or increased packet latency.

Disclosure of Invention

According to some aspects, the subject matter of the independent claims is provided. Some other aspects are defined in the dependent claims.

The summary section lists some example embodiments/aspects. Embodiments that do not fall within the scope of the claims are to be construed as examples useful for understanding the present disclosure.

According to an aspect, there is provided a method comprising: obtaining information indicating an association of random access resources with at least one synchronization signal block; obtaining information associating the pre-configured resource with the indicated random access resource; and determining an occasion of small data transmission associated with the at least one synchronization signal block according to the information associating the pre-configured resource with the indicated random access resource.

According to another aspect, there is provided a method comprising: associating the pre-configured resource with a random access resource associated with at least one synchronization signal block; sending the association information of the pre-configured resource and the indicated random access opportunity; and monitoring the timing of small data transmission associated with at least one synchronization signal block according to the association information of the pre-configured resource and the random access resource.

According to another aspect, there is provided an apparatus for a communication device, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtaining information indicating an association of random access resources with at least one synchronization signal block; obtaining information associating the pre-configured resource with the indicated random access resource; and determining an occasion of small data transmission associated with the at least one synchronization signal block according to the information associating the pre-configured resource with the indicated random access resource.

According to another aspect, there is provided an apparatus for a communication network, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: associating the pre-configured resource with a random access resource associated with at least one synchronization signal block; sending the association information of the pre-configured resource to the indicated random access opportunity; and monitoring the timing of small data transmission associated with at least one synchronization signal block according to the association information of the pre-configured resource and the random access resource.

More detailed aspects include the small data transmission by the terminal device utilizing at least one of the small data transmission occasions. Alternatively or additionally, receiving small data transmissions from the terminal device may be provided. The terminal device may be in an inactive radio resource control state.

The pre-configured resources may include at least one configured grant-based physical uplink shared channel resource and/or physical downlink control channel monitoring occasion.

The synchronization signal block may be provided by analog beamforming.

A frequency range of 2 or higher according to the 3GPP specifications may be used as a carrier for small data transmission.

One or more random access slots or random access occasions mapped to a Synchronization Signal Block (SSB) beam may be configured to serve as a time anchor for the pre-configured resources.

The association information of the pre-configured resource with the random access resource may comprise an indication of a time domain offset between the pre-configured resource and the associated random access resource.

The random access resource and the pre-configured resource may overlap in time.

The association information of the pre-configured resource with the random access resource may comprise an indication of a frequency domain offset between the pre-configured resource and the related random access resource.

The information may also include an indication of a ratio between opportunities available for small data transmissions and opportunities not available for small data transmissions. The ratio may be determined dynamically, for example based on the type of data to be transmitted.

The information associating the pre-configured resource with the indicated random access resource may be provided in a configuration grant of a small data transmission configuration in a radio resource control release message or a system information block message.

The information associating the pre-configured resource with the indicated random access resource may also be provided by explicit or implicit signaling.

The transmission opportunity associated with the synchronization signal block may be set based on a random access opportunity associated with the synchronization signal block.

According to yet another aspect, it may be determined that an opportunity for small data transmission associated with at least one synchronization signal block cannot be used for small data transmission based on information associating preconfigured resources with indicated random access resources. In response, a switch may then be made to a random access procedure for sending small data transmissions.

Means may also be provided for carrying out the operations and functions disclosed herein.

A computer software product may also be provided that embodies at least a portion of the functionality described herein. According to an aspect, the computer program comprises instructions for performing at least one of the methods described herein.

Drawings

Some aspects will now be described in more detail, by way of example only, with reference to the following examples and the accompanying drawings, in which:

FIG. 1 illustrates an example of a system in which the present invention may be implemented;

fig. 2 is an example of a control device;

fig. 3 and 4 are flow diagrams according to some examples;

FIGS. 5 and 6 are signaling flow diagrams between two devices;

FIG. 7 shows an example of a resource timing sequence;

FIG. 8 illustrates an example of using a scale factor; and

fig. 9 shows another signaling flow diagram.

Detailed Description

The following description gives an exemplary description of some of the possibilities for practicing the invention. Although the specification may refer to "an", "one", "some", or "some" examples or embodiments in various places throughout the text, this does not necessarily mean that each refers to the same embodiment example, or that a particular feature only applies to a single example or embodiment. Several individual features of the different examples and embodiments may also be combined to provide further embodiments.

A wireless communication system provides wireless communication to devices connected therein. Typically, an access point, such as a base station, is provided to enable the communication. Different scenarios are described below with the 3gpp5G wireless access architecture as an example of one access architecture. However, embodiments are not necessarily limited to such an architecture. Some examples of options that may be used for a suitable system are Universal Mobile Telecommunications System (UMTS) radio access network (UTRAN or E-UTRAN), long Term Evolution (LTE), LTE-a (LTE-advanced), wireless local area network (WLAN or Wi-Fi), worldwide Interoperability for Microwave Access (WiMAX), wiMAX, etc,

Personal Communication Services (PCS),

Wideband Code Division Multiple Access (WCDMA) using Ultra Wideband (UWB) technologyA sensor network, a mobile ad-hoc network (MANET), a cellular internet of things (IoT) RAN, and an internet protocol multimedia subsystem (IMS), or any combination and further advancements thereof.

Fig. 1 shows a wireless system 1 comprising a radio access system or Radio Access Network (RAN) 2. The radio access system may include one or more access points, or base stations 12. A base station may provide one or more cells. Each cell may provide a radio beam 11. The beams may be provided by analog or digital or hybrid beamforming. This example is schematically shown to include up to four beams per polarization in the Spatial Domain (SD). An access point may include any node (e.g., TRP,3GPP5G base stations such as a gNB, eNB, user equipment such as a UE, etc.) that may transmit/receive radio signals. Note that a large number of radio access systems may be provided in a communication system.

The communication device 10 is located in the service area of the radio access system 2 so the device 10 can listen to the access point 12. Communication from the device 10 to the access point 12 is commonly referred to as Uplink (UL). Communication from the access point 12 to the device 10 is commonly referred to as Downlink (DL).

Note that the broader range communication system is shown only as cloud 1, and may include a number of elements that are not shown for clarity. For example, a 5G-based system may include a terminal or User Equipment (UE), a 5G radio access network (5 GRAN) or next generation radio access network (NG-RAN), a 5G core network (5 GC), one or more Application Functions (AFs), and one or more Data Networks (DNs). The 5G-RAN may comprise one or more Gnnodebs (GNBs), or one or more Gnnodeb (GNB) distributed unit functions, which are connected to one or more Gnnodeb (GNB) centralized unit functions. The 5GC may also include some entities such as a Network Slice Selection Function (NSSF), etc.; a network opening function; a network storage function (NRF); a Policy Control Function (PCF); unified Data Management (UDM); an Application Function (AF); an authentication server function (AUSF); access and mobility management functions (AMFs); session Management Function (SMF), etc.

Device 10 may be any suitable communication device suitable for wireless communication. The wireless communication device may be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include a Mobile Station (MS) (e.g., a mobile device such as a mobile phone or so-called "smart phone"), a computer (e.g., a USB dongle (dongle)) equipped with a wireless interface card or other wireless interface facility, a Personal Data Assistant (PDA) or tablet computer with wireless communication capabilities, a Machine Type Communication (MTC) device, an internet of things (IoT) type communication device, or any combination of these devices, and so forth. The device may be provided as part of another device. The apparatus may receive signals over the air or over a radio interface by suitable means for receiving and may transmit signals by suitable means for transmitting radio signals. Communication may occur over multiple paths. To enable MIMO type communications, devices 10 and 12 may provide multiple antenna elements. These are schematically represented by antenna arrays 14 and 15.

A communication device such as an access point 12 or a user equipment 10 is provided with data processing means comprising at least one processor and at least one memory. Fig. 2 shows an example of a data processing apparatus 50 comprising

processors

52, 53 and one or more memories 51. Fig. 2 further shows the connections between the elements of the apparatus and the interfaces for connecting the data processing apparatus to other components of the device.

The at least one memory may include at least one ROM and/or at least one RAM. The communication device may include other possible components for use in software and hardware assisted performance of tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices, as well as implementing the location features described herein for the device. The at least one processor may be coupled to the at least one memory. The at least one processor may be configured to execute appropriate software code to implement one or more of the following aspects. The software codes may be stored in at least one memory, such as at least one ROM.

Certain aspects, configurations, and signaling of small data transmission related operations using 5G terminology are described below.

An independent Radio Resource Control (RRC) state, referred to as RRC _ INACTIVE, of an INACTIVE UE is introduced into a 3GPP new air interface (NR) Rel-15 to supplement the RRC _ CONNECTED and RRC _ IDLE states to provide lean signaling and energy-saving support for NR services between the RRC _ CONNECTED and RRC _ IDLE states. The RRC IDLE state enables a fast recovery of earlier suspended connections and starts transmitting small or sporadic amounts of data with lower initial access delay and associated signaling overhead compared to the RRC IDLE state. This is mainly facilitated by reducing the control signaling required to request and obtain resumption of the suspended RRC connection. Compared to RRC _ CONNECTED, a UE in RRC _ INACTIVE is able to achieve power savings, which benefits from, for example, longer PDCCH monitoring periods (e.g., for paging) and relaxed measurements. Furthermore, since the UE can move transparently to a RAN within a network defined by a set of cells called RAN Notification Areas (RNAs), mobility signaling (e.g., RRC measurement reports, handover (HO) messages) to the RAN and mobility signaling (e.g., to/from the AMF) to the core network can be reduced, as compared to keeping the UE in RRC _ CONNECTED.

The transition from RRC _ CONNECTED to RRC _ INACTIVE is triggered by the gNB sending a rrcreelease message containing the suspend configuration information. This includes the I-RNTI, the RAN-PaginCycle, the RAN-Notification information and a timer that controls when the periodic RNA update (RNAU) procedure should occur on the UE. When the UE moves to RRC _ INACTIVE, the UE Access Stratum (AS) Context (called UE INACTIVE AS Context) required for fast resume of suspended connections is maintained on both the UE side and the RAN side, which is identified on the network side by the UE identifier, i.e. INACTIVE-RNTI (I-RNTI).

According to the present arrangement, the small and infrequent data transmissions required by a UE in the RRC _ INACTIVE state require RRC connection recovery to switch to the RRC connected state to enable small data transmissions. Subsequent connection suspension back to the RRC _ INACTIVE state may then occur immediately after the data transmission. This occurs for every data transfer. Switching between states may result in unnecessary UE power consumption, signaling overhead, and/or increased packet delay.

Fig. 3 and 4 are operational flow diagrams according to general examples that avoid or at least reduce the need to switch between states that reduce data transmission.

Fig. 3 relates to operations at a network entity. In the method, the pre-configured resource is associated at 100 with a random access resource associated with at least one synchronization signal block. At 102, association information of the pre-configured resource with the indicated random access occasion is sent to at least one other entity. For example, the information is sent to the downlink device. The pre-configured resources may be referred to as occasions of small data transmission. At 104, small data transmission occasions associated with at least one synchronization signal block are monitored according to the association information of the pre-configured resource and the random access resource.

Fig. 4 illustrates a method of utilizing association information at a device. At 200, a device obtains information indicating an association of random access resources with at least one synchronization signal block. For example, acquiring may include reading an association of a random access occasion with a synchronization signal block in System Information Block (SIB) signaling. The method further comprises obtaining information associating the pre-configured resource with the indicated random access resource, at 202. At 204, an occasion for a small data transmission associated with at least one synchronization signal block is determined based on information associating pre-configured resources with the indicated random access resources.

At least one of the transmission occasions (e.g., one of the pre-configured resources) may be used for small data transmission. Fig. 4 shows a small data transmission by the device at 206. The device may send data to a network entity that will subsequently receive small data transmissions from the device based on the monitoring.

The following more detailed example illustrates how SSBs and Configured Grant (CG) resources are more efficiently associated and used from the network side for Small Data Transfers (SDT). Hereinafter, the device that performs small data transmissions is referred to as User Equipment (UE), but it is noted that this is intended to encompass any device capable of performing small data transmissions in accordance with the principles described herein. More specifically, in the following example, a UE in a Radio Resource Control (RRC) inactive state is enabled for Small Data Transmission (SDT) on a pre-configured physical shared resource by means of the CG-SDT procedure described herein.

A time association may be established between certain Configured Grant (CG) occasions of the configured resource configuration and certain Random Access Channel (RACH) resources configured for a User Equipment (UE). In a more specific example, a time association is established between certain Configured Grant (CG) occasions of a CG-PUSCH configuration that allow a UE to be used in at least one SSB beam to perform CG-based Physical Uplink Shared Channel (PUSCH) transmission while the UE is in a Radio Resource Control (RRC) inactive state (i.e., CG-SDT; small data transmission) and certain RACH resources configured for the UE for the first SSB beam (e.g., RACH slots and/or RACH Occasions (RO) configured to perform a random access procedure in a first Synchronization Signal Block (SSB) beam by the UE).

In NR, uplink transmission can be configured without the need to send a dynamic grant corresponding to each UL transmission opportunity. The configuration of these uplink resources, also referred to as Configuration Grant (CG) PUSCH resources, may be provided according to e.g. the scheme depicted in fig. 5a and 5 b. The uplink grant may follow, for example, the method named CG type 1, where CG resources are configured and activated via RRC signaling (including resource period and start time), or the method named CG type 2, where CG resources are provided (activated/deactivated) via a combination of RRC (configuration) and Physical Downlink Control Channel (PDCCH) addressed to CS-RNTI, configuration via RRC signaling, activation via PDCCH.

According to the example of fig. 6, the UE may use UL data on the pre-configured PUSCH resources to send the SDT payload with message 1. When it has a valid Timing Advance (TA) and other conditions are met, no random access procedure needs to be performed. The information of the pre-configured resource is transmitted in an RRC release message 0. The TA validity condition may include, before using CG-SDT resources, the UE ensuring that its newly received TA is valid by checking, for example, that a TA timer (TAT) is running, if the TAT is received, and that the defined TA validity condition is also valid. The latter may be based on, for example, a Reference Signal Received Power (RSRP) variation to be compared to an RSRP variation threshold.

For example, in cellular systems, TA is used to compensate for differences in propagation delay for UEs at different distances from the base station. When time multiplexing different UEs, it is important that the end of their transmission burst does not overlap with the beginning of the UE that is next to transmit and closer to the base station, so that a UE that is further away is required by the network to "advance" its uplink transmission relative to its observed downlink time. In systems that rely on orthogonal subcarriers and cyclic prefixes (e.g., systems such as LTE and NR), the frequency reuse of two uplink transmissions needs to be considered as being received at (nearly) the same time, so similar to the TDM example described above, TA adjustment can be used to compensate for propagation delay differences to avoid transmission problems with incorrect TAs. If no random access is made immediately before the CG-SDT transmission, the UE cannot receive the TA command from the network, so the CG-SDT can be used only if the current TA received earlier from the network is considered valid. This may be based on a defined TA verification procedure.

Further conditions to be checked may be defined before being allowed to use the allocated CG resources. The further conditions may include one or more of: the payload should belong to a dedicated radio bearer/signaling radio bearer (DRB/SRB) allowed for SDT, the data volume should be below a defined data volume threshold, the UE should be in the last serving cell of the allocated resources, the CG resources should be active, and the synchronization signal reference signal received power (SS-RSRP) of the beam selected for SDT transmission over the CG-based PUSCH resources should be above a defined RSRP threshold. If the authentication conditions defined for CG-SDT are not satisfied, CG-SDT may not be used and the UE may fall back to using the random access procedure.

Two frequency ranges are defined for the 5G NR. The frequency range 1 (FR 1) includes a frequency band below 6 GHz. Frequency range 2 (FR 2) includes frequency bands in the millimeter wave range (e.g., 24-52 GHz). NR employs a new frequency range, particularly millimeter-Wave (mm-Wave) frequencies in frequency bands such as 30GHz and frequency ranges above FR2, to achieve higher data rates, high quality of service, and enhanced capacity. At FR2 and above, beamforming is considered important in 5G NR because the antenna gain boost produced by the beamforming operation must overcome the relatively high propagation losses present in millimeter waves.

Analog or hybrid beamforming is commonly used for FR2 and above. Unlike digital beamforming, each group of antenna elements can only form one beam when analog beamforming is used. Conversely, the gNB may perform transmission and reception in FR2 via only one beam at a time per antenna panel.

UE transmissions in RRC inactive state may be made using Configuration Grant (CG) type 1 based Physical Uplink Shared Channel (PUSCH) resources in NR for small data transmissions. A UE in RRC inactive state may be mobile and therefore move transparently through the RAN within the received RAN Notification Area (RNA). As a result, the RAN may become unaware of the location of the UE at the cell level. Thus, the CG-SDT configuration may only be used when the UE is in or remains in the last serving cell that suspended the RRC connection of the UE and provided the CG-SDT configuration to the UE. This in turn may limit the decoding attempts of the potential CG-based transmission on the network side, which then only needs to be performed in the last serving cell. However, the UE may move within the coverage area of a different (SSB) beam of the last serving cell, and the last serving cell does not know which (SSB) beam the UE uses in the CG-SDT configuration beam to perform CG-based transmission. To address this issue, the cell may monitor potential CG-based PUSCH transmissions by its RRC inactive UEs from all configured beams.

If analog beamforming is employed, for example, in deployments operating at FR2 and above, and when a cell is monitoring one beam, the cell may not be monitoring from other beams at the same time. To address this issue, CG transmission occasions included in one CG configuration of a CG-SDT may be mapped to multiple SSB beams in a Time Division Multiplexed (TDM) manner, i.e., multiple SSBs may be configured for the CG-SDT, each allowed SSB beam being associated in time with a different CG occasion, so that the network knows the receive (SSB) beam according to the timing of the CG occasions that the UE may use to perform ULSDT transmissions. Establishing such an association statically in time (semi-) between an SSB and its allowed CG occasion in TDM fashion may not always be optimal, since it depends e.g. on the UE in RRC connected state that should be served by the cell. For example, if their load on one beam increases (e.g., there are more UEs in the RRC connected state in a given SSB beam), the cell may wish to increase the reception time through such beams by reducing CG occasions mapped to other beams, and vice versa. This dynamic reconfiguration of SSB-CG occasion associations may not be feasible because it may require frequent SIB updates to provide updated mappings to UEs in the RRC inactive state.

During SDT, the RRC state does not need to change, i.e., the UE can maintain the RRC inactive state throughout the SDT. However, in some cases, the RRC state may change after the UE initiates the SDT procedure. For example, the UE initiates SDT in an inactive state, and if SDT fails, the UE may transition to an idle state. Another example is when the UE initiates SDT in the inactive state but the network decides to transition the UE to the RRC connected state and continue data transmission in the connected state (stop SDT procedure). Further, the UE may initiate SDT in the inactive state, but the network may decide to reject the SDT procedure and may transition the UE to the idle state, e.g., for load reasons.

The CG-SDT resource may be provided with a time anchor point based on a random access occasion or time slot. A random access slot is a slot into which at least one random access occasion falls. For example, each RACH occasion falls in one RACH slot. A random access occasion (RO) may have a shorter duration than a slot duration, and a plurality of occasions may be configured in the same slot. If there are multiple ROs per RACH slot, it may not be sufficient to associate CG resources with the RACH slot, but the resources should be associated with the occasion. If the CG resource associated with one of the plurality of ROs is a PUSCH Transmission Occasion (TO), the CG resource will be a "short PUSCH" resource, i.e. a PUSCH resource that does not occupy the entire slot, e.g. it only occupies a certain number of 14 OFDM symbols in the slot.

In one example, a RACH slot/occasion mapped to one beam may be configured by the network to the UE as a time anchor for CG transmission occasions of a CG-PUSCH configuration that the UE may use in the same beam. Such a time association may be implemented, for example, as a time offset between a RACH occasion and a CG transmission occasion of a CG-PUSCH resource. In one example, different anchor RA occasions may be used for different beams. In another example, anchor RA occasions for one beam may be applied to define a corresponding anchor RA occasion in another beam.

In one example, the RACH resources (e.g., opportunities, time slots) used as time anchors may be the same as the resources configured for 4-step or 2-step RACH configuration dedicated to Small Data Transmission (SDT).

In one example, the RACH occasion can be different from the RACH resources configured for Small Data Transmission (SDT). For example, RACH resources may be configured for connection recovery or establishment procedures. Furthermore, the frequency offset related to the anchor RACH Occasion (RO) may be used to identify which CG (PUSCH) transmission occasion the UE should use for small data transmission.

For the case where different preambles within a RO are associated with different Synchronization Signal Blocks (SSBs), this may mean that the serving cell's transmit/receive point (TRP) has multiple antenna panels, each associated with a different SSB (i.e., analog beamforming is performed in each direction), so the serving cell can receive in multiple directions using these different panels. This also means that the TRP has a hybrid digital front end and therefore Rx beamforming can be performed in the digital domain. In both cases, the RO itself can serve as an indication that the TRP can listen to multiple Synchronization Signal Block (SSB) directions at the time of the RO.

Fig. 7 shows an example of the time and frequency relationship of RACH occasion and CG-PUSCH resources with respect to SSBx. Fig. 7 shows three examples of applying time and frequency offsets: (a) CG-PUSCH resources occur before an anchor RACH occasion; (b) CG-PUSCH resources overlap with RACH occasions; and (c) the CG-PUSCH resources advance the RACH occasion.

The time association may be established as a time overlap of a beam between the CGPUSCH transmission occasion for the CG-SDT in the beam and certain RACH resources associated with the beam. This is depicted in fig. 7 (b). This ensures that the cell can simultaneously monitor potential CG-based PUSCH transmissions in the same direction when performing e.g. monitoring of ROs in the respective beam directions. This can be provided without performance loss, which is desirable especially in deployments running at FR2 and above.

Such time overlap may also allow for operation without satisfying any verification conditions for CG-SDT and thus disabling CG-SDT, and the UE may then quickly fall back to perform RA-SDT procedures at the same transmission time in the selected beam.

The UE may be configured TO skip some CG PUSCH TOs. That is, for example, a case where an RO exists but cannot or is determined not to be used for small data transmission may sometimes be skipped. A factor may be defined that determines the ratio between opportunities that are available for small data transmissions and opportunities that are not available for small data transmissions. This may be provided by a scaling factor or a skipping factor. The time association may be established such that the CG occasions of the beams are configured to scale factor = N (integer) x RACH configuration period. That is, one CG opportunity may be configured for every N RACH occasions in a beam. For example, if the RACH period is set to 160ms (this may be set to 10ms-160 ms), the CG opportunity period may be set to 60 seconds, i.e., 375 (N = 375) x160 ms. Since the RACH configuration period can be short (10 ms-160 ms), this allows meaningful CG resource configuration based on traffic demand in RRC inactive state. If it is important that the SDT delay remain limited for a given traffic/DRB/QoS flow that allows CG-SDT to be used, the scaling factor may be set to a smaller value. As such, the ratio may be determined dynamically, e.g., based on the type of data to be transmitted.

In one example, the UE is provided with a new scale parameter, prach-configuration PeriodScaling-SDT, which defines the periodic repetition given by the following CG timing

prach-configuration PeriodScaling-SDT x RACH configuration period

I.e., one CG opportunity per NRACH slot and/or opportunity. For example, if the RACH period is set to 160ms, the CG occasion period may be set to 60 seconds if prach-configuration periodic scaling-SDT = 375.

An example of a skip is provided in fig. 8, showing an example of applying a ratio or a skip factor, where not all RACH occasions are used as anchor points for CG-PUSH resources. In this example, the CG-PUSCH resources overlap with the RACH occasions, the scaling factor is based on N =2.

The load may decrease or increase on one beam, for example when the number of UEs in RRC connected state in a given SSB beam changes. A cell may determine that it is necessary to increase or decrease the receive time through such beams by decreasing or increasing CG occasions mapped to other beams. The network entity may then dynamically allocate more or fewer RA opportunities. In this way, the number of SDT occasions can be adjusted even if the CG-SDT is not explicitly configured. In linking SDT resources to RA resources, an increase or decrease in RA resources will inherently result in an increase or decrease in the desired SDT resources without explicitly (re) configuring the SDT. Furthermore, the suggested scaling factor (between RACH occasions and CG resources) may be adapted to increase or decrease the number of CG resources compared to RA resources. When the scaling factor is up to 1 (i.e. a set of CG resources per RA occasion), the signaled offset will be sufficient information to indicate where the CG resources are. When the scaling factor >1 (i.e., more than one set of CG resources per RA opportunity), then the offset will serve as a time anchor for that set of CG resources, and the number of CG resources within that period of time will be multiplied by the scaling factor.

Fig. 9 depicts a further example of signaling between a gNB and a UE. Although fig. 9 and 6 list several parameters signaled between the UE and the network, in some embodiments not all of the listed parameters are necessary, but only one or more of the listed parameters are transmitted. For example, with respect to fig. 9, step 1 may, but need not, include all of the listed parameters and/or information elements.

In one example, a network (e.g., an NR serving cell) may configure a CG-PUSCH configuration for SDT that includes CG transmission occasions that allow at least one SSB to overlap in time with RACH slots and/or occasions associated with the respective SSB. One CG-PUSCH configuration of CG-SDT may comprise multiple CG transmission occasions, wherein each CG occasion may be mapped to one or more SSBs, and the transmission occasion(s) of one CG occasion is given by an RO/RACH slot mapped to the respective SSB(s).

After selecting the SSB direction for SDT, the UE may send a CG-based PUSCH data transmission via the selected SSB direction at a transmission time according to the CG occasion associated with the RACH occasion, and thus with the given SSB. That is, CG-based PUSCH transmissions may be transmitted via the selected SSB direction at a CG PUSCH transmission time given by a function of the RACH slot or RACH occasion mapped to the SSB. The association of the SSB with the time domain RACH Occasion (RO) may be based on, for example, SSB-perRACH-occupancy and dcb-preamblispssb parameters, etc. Such association may be provided by (dedicated) RRC signaling and/or SIBs, and for example by using ssb-perRACH-OccasionAndCB-preambessbb parameters.

For example, if CG occasion #1 is associated with SSB #1, whenever the beam selected for SDT is SSB #1, the CG transmission occasion that the ue can use for small data transmission is the RACH slot and/or RO of SSB # 1.

In one example, CG-based PUSCH transmission via an SSB beam in an RRC inactive state may be made only during RACH slots/ROs associated with the SSB beam.

The indicated CG occasion (PUSCH resource) may have at least a time association or frequency offset association with the RO (and its associated SSB). In such an example, a time overlap with the RO and a frequency offset (positive or negative) in the frequency domain towards the beginning or end of the RO is provided. The frequency offset may correspond to a highest (or lowest) PRB associated with a CG (PUSCH) occasion. According to an alternative, the PRB associated with the RO is subtracted from the available PRBs of the slot, and then the CG (PUSCH) occasion at the UE is determined based on the offset of the NW indication from the lowest/highest of the remaining PRBs and/or by a modulo operation applied to the UE RNTI (or other UE identifier) which is used to select the beginning (or end) PRB of the CG (PUSCH) occasion from the remaining PRBs.

In another example, there is a time offset between the CG (PUSCH) occasion and the RO (and associated SSB), and there is a frequency offset (positive or negative) in the frequency domain from the beginning or end of the RO, which corresponds to the highest (or lowest) PRB associated with the CG (PUSCH) occasion. There may also be a frequency offset (positive or negative) in the frequency domain to the beginning or end of the RO, which corresponds to the highest (or lowest) PRB associated with one CG (PUSCH) timing range. The UE may then determine the beginning (or end) PRB of its CG (PUSCH) occasion based on a modulo operation applied to the UE RNTI (or another UE identifier).

The association of CG occasions with RACH slots/occasions may be provided to the UE by explicit or implicit signaling. In the former case, the association may be provided by explicit signaling of such mapping/association, e.g., the mapping of TO RO (where TO is a function of RO) is explicitly provided as part of the CG-SDT configuration in the RRC release message. In the latter case, the association may be provided implicitly, e.g. by setting the values of CG transmission occasions associated with a given beam such that they overlap (or are e.g. time-offset) with the required RO occasions, without explicit signalling of the association between TO and RO. That is, the mapping of TO TO RO is implicitly given, where TO can be given with respect TO SFN.

Note that the proposed solution can be implemented regardless of the signaling options for the SSB to CG resource mapping of SDT. For example, each CG-configured CG resource may be associated with a set of SSBs configured through explicit signaling.

Note that the principles described herein may also be applied to digital beamforming and hybrid beamforming. In a hybrid case, some SSB groups may be provided by analog beamforming and other SSB groups may be provided by digital beamforming.

The examples described herein may provide various advantages. For example, the network may map the preconfigured resources of the SSBs with the resources that would be associated anyway with the SSBs of the random access procedure. This is especially beneficial in FR2 and above scenarios where the TRP of the serving cell can only monitor one SSB direction (i.e. analog beamforming) at a time. Radio resource waste can be avoided, especially if non-RACH PRBs in the RO are not utilized due to lack of UEs that need to perform Uplink (UL) transmission in the particular SSB direction at the time of the RO. The NW may also provide the UE with RO timely shutdown to allow the UE to perform, for example, legacy resume (legacy resume) or "fallback" to RA-SDT timely when CG-SDT conditions are not met (and thus CG-SDT cannot be used).

In addition to the benefits for FR2, these principles also apply to FR1. In FR1 deployments, the network can freely allocate CG resources to any location in the time domain that it wants, and it can benefit from the proposed RACH configuration coupling a CG-SDT configuration to the UE, as this simplifies the network configuration. CG-SDT capable UEs may have RACH configuration to perform, for example, conventional recovery or "fall back" to RA-SDT when CG-SDT conditions are not met. The latter "back-off" is faster if the transmission timing of the CG-SDT and the RA-SDT overlap in time or the timing of the RA-SDT follows the CG-SDT timing with a small time offset as described above.

Non-limiting examples of small data and infrequent data traffic applications that may benefit from the small data transfer process described herein include smart phone applications, traffic from Instant Messaging (IM) services, heartbeat/keep alive traffic from IM/email clients and other applications, push notifications from various applications, non-smart phone applications, traffic from wearable devices (e.g., periodic location information), sensors (e.g., industrial and/or automotive wireless sensor networks, transmitting temperature, pressure, vibration, etc. information on a periodic or triggered basis, etc.), smart meters and smart meter networks that send periodic readings.

It is noted that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention. Different features from different embodiments may be combined.

The embodiments may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any of the above described processes may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within the processor, magnetic media such as hard or floppy disks, and optical media such as DVDs and data variants CDs thereof.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable digital data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), gate level circuits, and processors based on a multi-core processor architecture, as non-limiting examples. Alternatively or additionally, some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the previously described functions and/or methodological processes. The circuitry may be provided in a network entity and/or a communication device and/or a server and/or a device.

As used in this application, the term "circuitry" may refer to one or more or all of the following:

(a) Hardware-only circuit implementations (e.g., implementations in analog and/or digital only circuits);

(b) A combination of hardware circuitry and software, for example: (i) A combination of analog and/or digital hardware circuitry and software/firmware and (ii) any portion of the hardware processor working with software (including digital signal processors), software, and memory to cause the communications device and/or server and/or network entity to perform the various functions previously described; and

(c) Hardware circuits and/or processors, such as microprocessors or portions of microprocessors, that require software (e.g., firmware) to operate, but software may not be present when operation is not required.

The definition of the circuit applies to all applications of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also encompasses embodiments of a hardware circuit or processor alone (or in part), or a hardware circuit or processor, and its (or their) accompanying software and/or firmware. The term circuitry also encompasses, for example, integrated devices.

It should be noted that although embodiments have been described for certain architectures, similar principles may be applied to other systems. Thus, although certain embodiments have been described above by way of example with reference to certain exemplary architectures for wireless networks, technical standards and protocols, the features described herein may be applied to any other suitable forms of systems, architectures and devices than those specifically shown and described in the above examples. It should also be noted that different combinations of the different embodiments are possible. It is also noted herein that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the spirit and scope of the present invention.

Claims

1. A method, comprising:

obtaining information indicating an association of a random access resource with at least one synchronization signal block;

obtaining information associating the pre-configured resource with the indicated random access resource; and

determining an occasion for small data transmission associated with at least one synchronization signal block based on information associating pre-configured resources with the indicated random access resources.

2. A method, comprising:

associating the pre-configured resource with a random access resource associated with at least one synchronization signal block;

sending the association information of the pre-configured resource and the indicated random access opportunity; and

and monitoring the transmission time of the small data associated with the at least one synchronous signal block according to the association information of the pre-configured resource and the random access resource.

3. A method as claimed in claim 1 or 2, comprising using at least one said small data transmission occasion for small data transmission by and/or reception of small data transmission from a terminal device.

4. The method of claim 3, the terminal device being in an inactive radio resource control state.

5. The method according to any of the preceding claims, wherein the pre-configured resources comprise at least one configured grant-based physical uplink shared channel resource and/or physical downlink control channel monitoring occasion.

6. The method of any of the preceding claims, the synchronization signal block being provided by analog beamforming.

7. The method of any preceding claim, using a frequency range of 2 or above according to 3GPP specifications for a carrier for small data transmission.

8. The method of any one of the preceding claims, comprising configuring at least one random access slot or random access occasion mapped to a synchronization signal block beam as a time anchor point for the pre-configured resource.

9. The method of any preceding claim, the information comprising an indication of a time domain offset between the pre-configured resource and an associated random access resource.

10. The method according to any of claims 1-8, wherein the random access resource and the pre-configured resource overlap in time.

11. The method of any preceding claim, the information comprising an indication of a frequency domain offset between the pre-configured resource and an associated random access resource.

12. A method as claimed in any preceding claim, the information comprising an indication of a ratio between occasions available for small data transmissions and occasions not available for small data transmissions.

13. The method of claim 12, the ratio is dynamically determined based on a type of data to be transmitted.

14. The method of any one of the preceding claims, the information associating the pre-configured resource with the indicated random access resource is provided in a configuration grant of a small data transmission configuration in a radio resource control release message or a system information block message.

15. The method of any of the preceding claims, the information associating the pre-configured resource with the indicated random access resource being provided via explicit signaling.

16. The method according to any of claims 1-14, wherein the information associating the pre-configured resource with the indicated random access resource is provided via implicit signaling.

17. The method of any of the preceding claims, the transmission occasion associated with the synchronization signal block is set based on a random access occasion associated with the synchronization signal block.

18. The method of any one of the preceding claims, comprising:

determining, based on the information associating the pre-configured resource with the indicated random access resource, that an occasion of a small data transmission associated with the at least one synchronization signal block cannot be used for the small data transmission, an

In response, a handover is made to a random access procedure for transmitting small data transmissions.

19. An apparatus for a communication device, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

obtaining information indicating an association of random access resources with at least one synchronization signal block;

determining an occasion for small data transmission associated with at least one synchronization signal block based on information associating the pre-configured resource with the indicated random access resource.

20. An apparatus for a communication network, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

21. The apparatus according to claim 19 or 20, configured to transmit and/or receive a small data transmission with at least one of the small data transmission occasions.

22. The apparatus of any of claims 19 to 21, the association of the pre-configured resources with random access resources for small data transmissions being provided for devices in an inactive radio resource control state.

23. The apparatus according to any of claims 19 to 22, wherein the pre-configured resources comprise at least one configured grant-based physical uplink shared channel resource and/or physical downlink control channel monitoring occasion.

24. The apparatus of any one of claims 19 to 23, the synchronization signal block being provided by analog beamforming.

25. The apparatus of any of claims 19 to 24, configured to use a frequency range of 2 or more according to 3GPP specifications for a small data transmission carrier.

26. The apparatus of any of claims 19 to 25, configured to use at least one random access slot or random access occasion mapped to a synchronization signal block beam as a time anchor for the pre-configured resource.

27. The apparatus of any one of claims 19 to 26, the association information of the pre-configured resource with an indicated random access occasion comprising an indication of a time domain offset of the pre-configured resource with an associated random access resource.

28. The apparatus of any one of claims 19 to 26, the random access resource and the pre-configured resource overlapping in time.

29. The apparatus of any of claims 19 to 28, the association information of the pre-configured resource with the indicated random access occasion comprising an indication of a frequency domain offset between the pre-configured resource and an associated random access resource.

30. The apparatus of any of claims 19 to 29, the association information of the pre-configured resources with the indicated random access occasions comprising an indication of a ratio of occasions available for small data transmission to occasions not available for small data transmission.

31. The apparatus of claim 30, configured to use a dynamic ratio based on the type of data to be transmitted.

32. The apparatus according to any one of claims 19 to 31, configured to transmit information associating the pre-configured resource with the indicated random access resource in a configuration grant of a small data transmission configuration in a radio resource control release message and/or a system information block message.

33. The apparatus according to any of claims 19 to 32, configured to explicitly signal information associating the pre-configured resource with an indicated random access resource.

34. The apparatus of any of claims 19 to 32, configured to implicitly signal information associating the pre-configured resource with the indicated random access resource.

35. The apparatus of any one of claims 19 to 34, the transmission occasion associated with a synchronization signal block is set based on a random access occasion associated with the synchronization signal block.

36. The apparatus according to any of claims 19 to 35, configured to determine, based on the information associating the pre-configured resource with the indicated random access resource, that a small data transmission occasion associated with at least one synchronization signal block cannot be used for small data transmission, and in response, to switch to a random access procedure for transmitting the small data transmission.

37. A computer readable medium comprising program code for causing a processor to perform the method of any of claims 1-18.