WO2022233005A1

WO2022233005A1 - Small data transmissions

Info

Publication number: WO2022233005A1
Application number: PCT/CN2021/091962
Authority: WO
Inventors: Daniela Laselva; Michal Maternia; Nuno Manuel KIILERICH PRATAS; Chunli Wu; Karri Markus Ranta-Aho
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2022-11-10
Also published as: CN115589793A

Abstract

Apparatuses and methods are disclosed for processing small data transmissions. A device acquires information indicating association of random access resources with at least one synchronization signal block and information associating pre-configured resources to the indicated random access resources. Determination of occasions for small data transmission associated with the at least one synchronization signal block is provided based on the information associating the pre-configured resources to the indicated random access resources.

Description

SMALL DATA TRANSMISSIONS

Field

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

Background

Data can be communicated between two or more communication devices such as user or terminal devices, base stations/access points and/or other nodes. Communication may be provided, for example, by means of a communication network and one or more compatible communication devices. A communication device at a network side provides an access point to the system and is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling other devices to access the communication system. Communication may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email) , text message, multimedia and/or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication, multimedia services and access to a data network system, such as the Internet. It is also possible to communicate small and/or transmissions of data.

In a mobile or wireless communication system at least a part of data communication between at least two devices occurs over a wireless or radio link. Examples of wireless systems comprise public land mobile networks (PLMN) , satellite-based communication systems and different wireless local networks, for example wireless local area networks (WLAN) . The wider communication system by means of an appropriate communication device or terminal. Such a device may be referred to as user equipment (UE) .

A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other users. A communication device of a user may access a carrier provided by a station at a radio access network, for example a base station, and transmit and/or receive communications on the carrier. Multiple carriers can be provided, e.g., by beams. Beams can be formed by means of analogue, digital or hybrid beamforming.

The 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 which shall be used for the connection are also typically defined. One example of a communications 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 so-called fifth generation (5G) or New Radio (NR) networks. 5G is being standardized by the 3rd Generation Partnership Project (3GPP) . The successive versions of the standard are known as Releases (Rel) .

Small and infrequent data transfers may be needed by a device which is in inactive state. A radio resource control (RRC) connection resume is made to switch to RRC connected state to enable transfer of the small data. A subsequent suspension of the connection back to the inactive state occurs after the data transfer. The switching between states may cause unnecessary power consumption, signalling overhead and/or increased packet latency.

Summary

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

Some example embodiments/aspects are listed in the Summary–section. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure.

In accordance with an aspect there is provided a method comprising: acquiring information indicating association of random access resources with at least one synchronization signal block; acquiring information associating pre-configured resources to the indicated random access resources; and determining occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources.

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

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 a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: acquire information indicating association of random access resources with at least one synchronization signal block; acquire information associating pre-configured resources to the indicated random access resources; and determine occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources.

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 a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: associate pre-configured resources to random access resources associated with at least one synchronization signal block; send information of the association of the pre-configured resources to the indicated random access occasions; and monitor occasions for small data transmission associated with the at least one synchronization signal block according to the information of the association of the pre-configured resources to the random access resources.

A more detailed aspect comprises utilizing at least one of said occasions for small data transmission for a small data transmission by a terminal device. Alternatively, or in addition, reception of a small data transmission from a terminal device can be provided. The terminal device can be in an inactive radio resource control state.

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

A synchronization signal block may be provided by analogue beamforming.

Frequency Range 2 according to 3GPP specifications or above may be used for the carrier for small data transmissions.

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.

Information of association of pre-configured resources to random access resources may comprise an indication of an offset in time domain between the pre-configured resources and the associated random access resources.

Random access resources and pre-configured resources may overlap in time.

Information of association of pre-configured resources to random access resources may comprise an indication of an offset in frequency domain between the pre-configured resources and the associated random access resources.

The information may further comprise an indication of a ratio between occasions that can be used for small data transmissions and occasions that cannot be used for small data transmission. The ratio can be determined dynamically, for example based on the type of data to be transmitted.

Information associating pre-configured resources to indicated random access resources may be provided in a configured grant for a small data transmission configuration in a radio resource control release message or a system information block message.

Information associating pre-configured resources to indicated random access resources may also be provided via explicit or implicit signalling.

Transmission occasions associated with a synchronization signal block can be set based on random access occasions associated with the synchronization signal block.

In accordance with a yet further aspect it can be determined that occasions for small data transmission associated with at least one synchronization signal block based on information associating pre-configured resources to indicated random access resources cannot be used for a small data transmission. In response, switching to a random access procedure for the transmission of the small data transmission may follow.

Means for implementing the herein disclosed operations and functions can also be provided.

A computer software product embodying at least a part of the herein described functions may also be provided. In accordance with an aspect a computer program comprises instructions for performing at least one of the methods described herein.

Brief description of Drawings

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

Figure 1 illustrates an example of a system where the invention can be practiced;

Figure 2 shows an example of a control apparatus;

Figures 3 and 4 are flowcharts according to certain examples;

Figures 5 and 6 are signaling flowcharts between two devices;

Figure 7 shows examples timing of resources;

Figure 8 shows examples of use of a scaling factor; and

Figure 9 shows another signaling flow chart.

Detailed description of examples

The following description gives an exemplifying description of some possibilities to practise the invention. Although the specification may refer to “an” , “one” , or “some” examples or embodiment (s) in several locations of the text, this does not necessarily mean that each reference is made to the same example of embodiment (s) , or that a particular feature only applies to a single example or embodiment. Single features of different examples and embodiments may also be combined to provide other embodiments.

Wireless communication systems provide wireless communications to devices connected therein. Typically, an access point such as a base station is provided for enabling the communications. In the following, different scenarios will be described using, as an example of an access architecture, a 3GPP 5G radio access architecture. However, embodiments are not necessarily limited to such an architecture. Some examples of options for suitable systems are the 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) ,

personal communications services (PCS) ,

wideband code division multiple access (WCDMA) , systems using ultra-wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) , cellular internet of things (IoT) RAN and Internet Protocol multimedia subsystems (IMS) or any combination and further development thereof.

Figure 1 shows a wireless system 1 comprising a radio access system or radio access network (RAN) 2. A radio access system can comprise one or a plurality of access points, or base stations 12. A base station may provide one or more cells. Each cell can provide radio beams 11. The beams can be provided by means of analogue or digital or hybrid beamforming. The example is shown schematically to comprise up to four beams per polarization in spatial domain (SD) . An access point can comprise any node that can transmit/receive radio signals (e.g., a TRP, a 3GPP 5G base station such as gNB, eNB, a user device such as a UE and so forth) . It is noted that a great number of radio access systems can be provided in a communication system.

A communications device 10 is located in the service area of the radio access system 2, and the device 10 can thus listen to the access point 12. The communications from the device 10 to the access point 12 is commonly referred to as uplink (UL) . The communications from the access point 12 to the device 10 is commonly referred to as downlink (DL) .

It is noted that the wider communication system is only shown as cloud 1 and can comprise a number of elements which are not shown for clarity. For example, a 5G based system may be comprised by a terminal or user equipment (UE) , a 5G radio access network (5GRAN) or next generation radio access network (NG-RAN) , a 5G core network (5GC) , one or more application function (AF) and one or more data networks (DN) . The 5G-RAN may comprise one or more gNodeB (GNB) or one or more gNodeB (GNB) distributed unit functions connected to one or more gNodeB (GNB) centralized unit functions. The 5GC may also comprise entities such as Network Slice Selection Function (NSSF) ; Network Exposure Function; Network Repository Function (NRF) ; Policy Control Function (PCF) ; Unified Data Management (UDM) ; Application Function (AF) ; Authentication Server Function (AUSF) ; an Access and Mobility Management Function (AMF) ; Session Management Function (SMF) and so on.

The device 10 may be any suitable communications device adapted for wireless communications. A wireless communications device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) (e.g., a mobile device such as a mobile phone or what is known as a ’smart phone’ ) , a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle) , personal data assistant (PDA) or a tablet provided with wireless communication capabilities, machine-type communications (MTC) devices, Internet of Things (IoT) type communications devices or any combinations of these or the like. The device may be provided as part of another device. The device may receive signals over an air or radio interface via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. The communications can occur via multiple paths. To enable MIMO

type communications devices

10 and 12 may be provided with multiantenna elements. These are schematically denoted by

antenna arrays

14 and 15.

A communications device such as the access point 12 or the user device 10 is provided with data processing apparatus comprising at least one processor and at least one memory. Figure 2 shows an example of a data processing apparatus 50 comprising processor (s) 52, 53 and memory or memories 51. Figure 2 further shows connections between the elements of the apparatus and an interface for connecting the data processing apparatus to other components of the device.

The at least one memory may comprise at least one ROM and/or at least one RAM. The communications device may comprise other possible components for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communications devices, and implementing the herein described features of positioning of the device. The at least one processor can be coupled to the at least one memory. The at least one processor may be configured to execute an appropriate software code to implement one or more of the following aspects. The software code may be stored in the at least one memory, for example in the at least one ROM.

The following describes certain aspects, configurations and signaling for small data transmission transmission related operations using 5G terminology.

An independent radio resource control (RRC) state for inactive UEs, referred to as RRC_INACTIVE, was introduced in 3GPP New Radio (NR) Rel-15 to complement states RRC_CONNECTED and RRC_IDLE to provide a state for lean signalling and energy-efficient support of NR services between the RRC_CONNECTED and RRC_IDLE states. The RRC_INACTIVE state enables quick resume of an earlier suspended connection and start of transmission of small or sporadic data with low initial access delay and associated signalling overhead compared to the RRC_IDLE state. This is mainly facilitated by reduced control signalling required for requesting and obtaining the resume of a suspended RRC connection. A UE in RRC_INACTIVE is able to achieve power savings, benefiting from, e.g., s larger period of PDCCH monitoring (e.g. for paging) and relaxed measurements compared to RRC_CONNECTED. Furthermore, compared to keeping the UE in RRC_CONNECTED, mobility signalling both to RAN (e.g. RRC measurement reporting, handover (HO) messages) and to the core network (e.g. to/from the AMF) can be reduced as the UE can move transparently to the RAN within a network defined by a set of cells known as RAN notification area (RNA) .

The transition from RRC_CONNECTED to RRC_INACTIVE, is triggered by the gNB with the transmission of a RRCRelease message that includes the suspend configuration information. This includes I-RNTI, RAN-PagingCycle, RAN-NotificationAreaInfo and a timer that controls when the periodic RNA Update (RNAU) procedure should occur at the UE. When a UE is moved to RRC_INACTIVE, the UE Access Stratum (AS) context (referred to as UE Inactive AS Context) , necessary for the quick resume of the suspended connection, is maintained both at the UE side and RAN side, and it is identified at the network side by the UE identifier, i.e. Inactive-RNTI (I-RNTI) .

According to the current arrangement small and infrequent data transfers needed by a UE in the RRC_INACTIVE state entail that an RRC connection resume is made to switch to the RRC Connected state to enable transfer of the small data. A subsequent suspension of the connection back to the RRC_INACTIVE state can then occur immediately after the data transfer. This can occur for each data transmission. The switching between states has the potential to result in unnecessary UE power consumption, signalling overhead and/or increased packet latency.

Figures 3 and 4 are flowcharts for operation according to generic examples avoiding, or at least reducing the need for switching between states for small data transmissions.

Figure 3 relates to operation at a network entity. In the method pre-configured resources are associated at 100 to random access resources associated with at least one synchronization signal block. At 102 information of the association of the pre-configured resources to the indicated random access occasions is sent to at least one other entity. For example, the information is sent to a downlink device. The pre-configured resources may be called occasions for small data transmission. At 104 monitoring is provided for occasions for small data transmission associated with the at least one synchronization signal block according to the information of the association of the pre-configured resources to the random access resources.

Figure 4 shows a method at a device utilising information of the association. The device acquires at 200 information indicating association of random access resources with at least one synchronization signal block. For example, the acquiring may comprise reading an association of a random access occasion to a synchronization signal block in system information block (SIB) signalling. The method further comprises at 202 acquiring information associating pre-configured resources to the indicated random access resources. At 204 occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources are determined.

At least one of said transmission occasions (e.g. one of the preconfigured resources) may be utilized for small data transmission. Figure 4 illustrates a small data transmission by the device at 206. The device may transmit the data to a network entity who would then receive the small data transmission from the device based on the monitoring.

The following describes more detailed examples how to associate and use SSB and configured grant (CG) resources for small data transmission (SDT) more efficiently from the network side. In the following the device making the small data transmission is referred as user equipment (UE) but it is noted that this is intended to cover any device capable of making a small data transmission according to the herein described principles. More particularly, in the following examples UEs in radio resource control (RRC) inactive state are enabled to perform small data transmission (SDT) over a pre-configured physical shared resource via what is termed herein a CG-SDT procedure.

A time association can be established between certain configured grant (CG) occasions of a 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 the UE is allowed to use in at least one SSB beam to perform a CG-based Physical Uplink shared channel (PUSCH) transmission while the UE is in 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 (ROs) configured to perform the random access procedure by the UE in the first Synchronization Signal block (SSB) beam) .

In NR it is possible to configure uplink transmissions without the need to transmit a dynamic grant in correspondence of each UL transmission occasion. The configuration of these uplink resources, also referred to as Configured Grant (CG) PUSCH resources, may be provided according to schemes such as depicted in Figures 5a and 5b. The uplink grant can follow, e.g., approaches denoted CG Type 1 where CG resources are configured and activated via RRC signalling (including the resources periodicity and starting time) or CG Type 2 where CG resources are provided via a combination of RRC (configuration) and physical downlink control channel (PDCCH) addressed to CS-RNTI (activation/deactivation) , configuring being via RRC signalling and activation via the PDCCH.

In accordance an example shown in Figure 6 UL data on pre-configured PUSCH resource can be used by a UE to transmit an SDT payload by message 1. when it has a valid timing advance (TA) and other conditions are met, without the need to perform a random access procedure. Information on the preconfigured resource is communicated in the RRC release message 0. TA validity conditions may include that before using a CG-SDT resource, the UE has ensured that its last received TA is valid by checking e.g. that the TA timer (TAT) is running, if TAT was received, and that the defined TA validity condition (s) are also valid. The latter may be based, for example, on a reference signal received power (RSRP) variation to be compared to RSRP variation thresholds.

For example, in cellular systems TA is used to compensate for the propagation delay differences of UEs being at different distance from the base station. When time multiplexing different UEs, it is important that the UE farther away does not have the end of its transmission burst overlap with the start of the UE that is next to transmit and is close to the base station, so the UE farther away is asked by the network to ‘advance’ its uplink transmission in time relative to its observed downlink time. In systems relying in orthogonal subcarriers and cyclic prefix (e.g. systems like LTE and NR) , the frequency multiplexing of two uplink transmissions would need to be seen as received at (almost) same timing, so similar to the TDM example above, a TA adjustment can be used to compensate for propagation delay differences to avoid problems with transmissions with incorrect TA. If no random access is performed immediately prior to the CG-SDT transmission, then the UE is unable to receive a TA command from the network, and thus CG-SDT can be used only when the current TA which was received earlier from the network is deemed to be valid. This may be based on a defined TA validation procedure.

Further conditions to check may be defined before being allowed to use the assigned CG resources. The further conditions may comprise one or more of the following: the payload should belong to a Dedicated Radio Bearer /Signalling 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 that assigned the resources, the CG resources should be valid, and the synchronization signal reference signal received power (SS-RSRP) of the beam selected for the SDT transmission via a CG based PUSCH resource should be above a defined RSRP threshold. In case the validation conditions defined for CG-SDT are not met, CG-SDT may not be used and the UE can fall back to use a random access procedure.

Two frequency ranges have been defined for 5G NR. Frequency Range 1 (FR1) includes sub-6 GHz frequency bands. Frequency Range 2 (FR2) includes frequency bands in the mmWave range (e.g. 24–52 GHz) . New frequency ranges are taken into use in NR, especially in millimetre-wave (mm-Wave) frequencies at bands such as 30GHz and frequency ranges above FR2 to obtain higher data rates, high quality of service and enhanced capacity. In FR2 and above, beamforming is considered important in 5G NR since the resulting antenna gain boost of beamforming operations has to overcome the relatively high propagation losses present in mm-Wave.

Analogue or hybrid beamforming is commonly used in FR2 and above. Unlike in digital beamforming, only one beam per set of antenna elements can be formed when using analogue beamforming. In turn, the gNB can perform transmission and reception via only one beam at a time in FR2 per antenna panel.

UE transmissions in RRC Inactive state can be made using configured grant (CG) type 1 based physical uplink shared channel (PUSCH) resources in NR to enable small data transmissions. UEs in the RRC Inactive state can be mobile and therefore move within the received RAN Notification Area (RNA) transparently through the RAN. As a result, the RAN may become unaware of the location of the UE at a cell level. Because of that, the CG-SDT configuration may be used only if the UE is, 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 potential CG based transmissions at the network side, which then only need to be performed at the last serving cell. However, the UE can move within the coverage area of the different (SSB) beams of the last serving cell, and the last serving cell is unaware of which (SSB) beam the UE may use to perform a CG based transmission out of the configured beams for CG-SDT. To address this, the cell can monitor for potential CG based PUSCH transmissions made by its RRC Inactive UE from all configured beams.

If analogue beamforming is adopted, e.g., in deployments operating at FR2 and above, and while the cell is monitoring for one beam, the cell may not monitor from other beams simultaneously. To address this the CG transmission occasions comprised within one CG configuration of CG-SDT can be mapped to multiple SSB beams in a time division multiplexing (TDM) manner, i.e. a number of SSBs can be configured for CG-SDT and each allowed SSB beam is associated with different CG occasions in time, so that the network knows the reception (SSB) beam based on the timing of the CG occasion the UE can be using to perform the UL SDT transmission. Making such association in a TDM manner between an SSB and its allowed CG occasions in time (semi) statically may not always be optimal since this depends, e.g., on the UEs in RRC connected state that should be served by the cell. For example, if their load increases on one beam (e.g. more UEs in RRC Connected state are present in the given SSB beam) , the cell may want to increase the reception time through such beam by decreasing the CG occasions mapped to other beams, and vice-versa. A dynamic reconfiguration of such SSB-CG occasions association may not be feasible because it may entail a frequent SIB update to provision the updated mapping to the UEs in RRC inactive state.

The RRC state does not need to change during the SDT procedure, i.e. the UE can remain in RRC Inactive throughout the entire SDT procedure. However, the RRC state may change in some cases after the UE has initiated the SDT procedure. For example, the UE initiates SDT in inactive state and if SDT fails the UE may transition to Idle. Another example is when the UE initiates SDT in inactive state but the network decides to transition the UE to RRC Connected state and continue data transfer in the Connected state (stopping the SDT procedure) . Also, a UE may initiate SDT in inactive state but the network can decide to reject the SDT procedure and can transition the UE to the Idle state e.g. due to load reasons.

A time anchor can be provided for the CG-SDT resources based on random access occasions or slots. A random access slot is a slot in which at least one random access occasion falls. For example, every RACH occasion falls in a RACH slot. A random access occasion (RO) can have a shorter duration than the slot duration and multiple occasions can be configured in the same slot. If there are multiple ROs per RACH slot, then it may not be sufficient to associate the CG resource to the RACH slot, but the resource shall be associated to the occasion. If a CG resource associated to one of the multiple ROs is a PUSCH transmission occasion (TO) , then the CG resource would be a “short PUSCH” resource, i.e. a PUSCH resource which does not occupy an entire slot, and e.g. it occupies only a certain number of the 14 OFDM symbols in the slot.

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

In one example, the RACH resources (e.g. occasions, slots) used as time anchor can be the same to the ones configured to a 4-step or 2-step RACH configuration dedicated to small data transmission (SDT) .

In one example, the RACH occasions can be different from the RACH resources configured for small data transmission (SDT) . For example, the RACH resources may be configured for a connection resume or establishment procedure. Additionally, a frequency offset in relation to the anchor RACH Occasion (RO) can be used to identify which CG (PUSCH) transmission occasion the UE should use for small data transmission.

For a case where different preambles within a RO are associated with different Synchronization Signal blocks (SSBs) , this can imply that the Transmission /Reception Point (TRP) of the serving cell has multiple antenna panels, each associated with different SSBs (i.e. performing analogue beamforming in each direction) and therefore the serving cell is able to use those different panels to receive in multiple directions. This can also imply that the TRP has a hybrid-digital frontend and is therefore able to perform the Rx beamforming in the digital domain. In both cases the RO itself can serve as indication that the TRP will be able to listen in multiple Synchronization Signal block (SSB) directions at the RO time.

An example for time and frequency relation between an RACH occasion and CG-PUSCH resource relative to an SSB x is illustrated in Figure 7. Figure 7 shows three examples for application of time and frequency offsets: (a) the CG-PUSCH resource occurs before the anchor RACH occasion; (b) the CG-PUSCH resources overlaps the RACH occasion; and (c) the CG-PUSCH resource precedes the RACH occasion.

A time association can be established as an overlap in time for a beam between the CG PUSCH transmission occasions for CG-SDT in the beam and certain RACH resources associated to the beam. This is depicted in Figure 7 (b) . This ensures that while performing the monitoring of e.g. a RO in the corresponding beam direction, a cell can at the same time monitor for potential CG-based PUSCH transmissions in the same direction. This can be provided without penalty in view of performance, which is desirable especially in deployments operating at FR2 and above.

Such overlap in time may also allow operation where, in case any validation condition of CG-SDT is not met and, thus, CG-SDT cannot be used, then the UE can quickly fall back to perform a RA-SDT procedure in the selected beam at the same transmission time.

A UE may be configured to skip some CG PUSCH TOs. That is, e.g., sometime instances where ROs are present but cannot or are decided not to be used for small data transmission may be skipped. A factor determining a ratio between the occasions that can be used for small data transmissions and the occasions that cannot be used for small data transmission can be defined. This can be provided by means of a scaling factor, or a skipping factor. A time association may be established such that a CG occasion for a beam is configured with a scaling factor = N (integer) x RACH configuration period. That is, one CG occasion can be configured in a beam for every N RACH occasions in the beam. For example, if the RACH periodicity is set to 160ms (this can be set between 10ms and 160ms) , then the CG occasion period can be set to 60 sec, i.e. 375 (N=375) x 160 ms. As the RACH configuration period may be quite short (10ms -160ms) , this allows to make the CG resource configuration meaningful as per the traffic needs in RRC inactive state. The scaling factor can be set to smaller value (s) in case it is crucial that the SDT delay is kept limited for a given traffic/DRB/QoS Flow allowed to use CG-SDT. As such, it is possible to that the ratio can be determined dynamically, for example based on the type of data to be transmitted.

In one example, the UE is provided a new scaling parameter prach-ConfigurationPeriodScaling-SDT which defines that the CG occasions are repeated with a period given by

prach-ConfigurationPeriodScaling-SDT x RACH configuration period i.e. one CG occasion per N RACH slots and/or occasions. For example, if the RACH periodicity is set to 160ms, then the CG occasion period can be set to 60 sec if prach-ConfigurationPeriodScaling-SDT = 375.

An example of the skipping is provided in Figure 8 showing an example of the application of a scaling or skipping factor where not all RACH Occasions are used as anchor for the CG-PUSH resource. In this example the CG-PUSCH resource overlaps with the RACH Occasion and the scaling factor is based on N=2.

The load can decrease or increase on one beam e.g. where the number of UEs in RRC Connected state present in a given SSB beam varies. The cell may determine it necessary to increase or decrease the reception time through such beam by decreasing or increasing the CG occasions mapped to other beams. The network entity can then dynamically allocate more or less RA occasions. By means of this the number of SDT occasions can be adjusted, even without explicit configuration for the CG-SDT. When linking the SDT resources to RA resources, the increase or decrease of RA resources will inherently lead to the desired increase or decrease of SDT resources, without explicit (re) configuration for the SDT. Additionally, the proposed scaling factor (between RACH occasions and CG resources) can be adapted to increase or decrease the amount of CG resources compared with the RA resources. For scaling factors up to 1 (i.e. one set of CG resources per RA occasions) the offset as signalled would be enough information to indicate where the CG resources are. For scaling factors >1 (i.e. more than one set of CG resources per RA occasion) , then the offset would be used as the time anchor point of the set of CG resources which the number of CG resources in time would be multiplied with the scaling factor.

Figure 9 depicts further examples for signalling between a gNB and a UE. Although Figure 9 and Figure 6 list several parameters that are being signalled between UE and network, in some embodiments not all listed parameters are required but only one or more of the parameters that are listed are transmitted. E. g. for Figure 9, step 1 may but is not required to include all of the listed parameters and/or information elements.

In one example, the network (e.g. NR serving cell) can configure a CG-PUSCH configuration for SDT, which includes CG transmission occasions allowed for at least one SSB overlapping in time with the RACH slots and/or occasions associated to the corresponding SSB. One CG-PUSCH configuration for CG-SDT can include multiple CG transmission occasions, where each CG occasion can be mapped to one or more SSBs, and the transmission occasion (s) of one CG occasion are given by the RO (s) /RACH slots mapped to the corresponding SSB (s) .

After selecting an SSB direction for SDT, the UE can send a CG-based PUSCH data transmission via the selected SSB direction at the transmission time according to CG occasion (s) associated to the RACH occasion (s) in turn associated with the given SSB. That is, a CG-based PUSCH transmission can be sent via a selected SSB direction at a CG PUSCH transmission time given as a function of a RACH slot or RACH occasion mapped to the SSB. The association of SSB(s) to the time-domain RACH Occasion (RO) can be, e.g., based on ssb-perRACH-OccasionAndCB-PreamblesPerSSB parameter or the like. Such association may be provisioned via (dedicated) RRC signaling and/or SIB, and by using the ssb-perRACH-OccasionAndCB-PreamblesPerSSB parameter, for example.

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

In one example, a CG based PUSCH transmission via an SSB beam in RRC Inactive can be done only during a RACH slot /RO associated to the SSB beam.

The indicated CG occasions (PUSCH resources) can have at least a time association or a frequency offset association to the RO (and its associated SSB) . In an example of this, an overlap in time with the RO and a frequency offset (positive or negative) to the start or end of the RO in the frequency domain are provided. The frequency offset can correspond to the highest (or lowest) PRB associated with the CG (PUSCH) occasion. According to an alternative the PRBs associated with the ROs are subtracted from the available PRBs in the slot, and the CG (PUSCH) occasion is then determined at the UE based on a NW indicated offset from the lowest/highest of the remaining PRBs and/or by a modulus operation applied to the UEs RNTI (or other UE identifier) that is used to select the start (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 a RO (with an associated SSB) and a frequency offset (positive or negative) to the start or end of the RO in the frequency domain, which corresponds to the highest (or lowest) PRB associated with the CG (PUSCH) occasion. It is also possible to have a frequency offset (positive or negative) to the start or end of the RO in the frequency domain, which corresponds to the highest (or lowest) PRB associated with a range of CG (PUSCH) occasions. The UE can then determine the start (or end) PRB of its CG (PUSCH) occasion based on a modulus operation applied to the UEs RNTI (or another UE identifier) .

The association of a CG occasion to a RACH slot/occasion can be provisioned to the UE by explicit or implicit signalling. In the former case, the association can be provided by the explicit signalling of such mapping /association, e.g., the mapping TOs to ROs where the TOs are given in function of ROs is explicitly provided as part of the CG-SDT configuration in the RRC Release message. In the latter case, the association can be provided implicitly by, e.g., setting the values of the CG transmission occasions associated to a given beam in such a way that they are overlapping with (or e.g. with a time-offset to) the desired RO occasions, without an explicit signaling of the association between TOs and ROs. That is, the mapping between TOs to ROs is given implicitly, wherein the TOs can be given relatively to the SFN.

It is noted that the proposed solution can be implemented irrespective of the signalling option for SSB-to-CG resource mapping for SDT. For example, the CG resources per CG configuration can be associated with a set of SSB (s) configured by explicit signalling.

It is noted the herein described principles can also be applied to digital beamforming and hybrid beamforming as well. In the hybrid case this some set (s) of SSBs can be provided via analogue beamforming and other set (s) of SSBs can be provided via digital beamforming.

The herein described examples can provide various advantage. For example, a network can map preconfigured resources to an SSB using resources that will anyway be associated with the SSB for random access procedure. This can be beneficial in particular in FR2 and above where the serving cell’s TRP can only monitor one SSB direction at a time (i.e. analogue beamforming) . Radio resource wastage may be avoided, in particular if incurred by non-RACH PRBs in the ROs not being utilized due to lack of UEs needing to perform uplink (UL) transmission in that particular SSB direction at the RO time. A NW may also provide to the UE a RO close in time that allows the UE to timely perform e.g. a legacy resume or a “fall back” to RA-SDT, if CG-SDT conditions are not met (and hence CG-SDT cannot be used) .

In addition to being beneficial for FR2, the principles can also be applied in FR1. The network has the freedom to allocate CG resources wherever it wants in time domain in FR1 deployments, and it can benefit from the proposed coupling of the CG-SDT configuration to the RACH configuration of the UE as that simplifies the network configuration. A UE capable of CG-SDT can have a RACH configuration to perform e.g. legacy resume or to “fall back” to RA-SDT if CG-SDT conditions are not met. The latter “fall-back” would be faster if the transmission occasions for CG-SDT and RA-SDT overlap in time or RA-SDT’s occasions follow by a small time offset the CG-SDT occasions as described above.

Non-limiting examples of small and infrequent data traffic applications that may benefit from the herein described small data transmission procedure include smartphone applications, traffic from instant messaging (IM) services, heart-beat/keep-alive traffic from IM/email clients and other applications, push notifications from various applications, non-smartphone applications, traffic from wearables (e.g. periodic positioning information) , sensors (e.g. industrial and/or automotive wireless sensor networks transmitting information on temperature, pressure, vibrations etc. periodically or in an event triggered manner etc) , smart meters and smart meter networks sending periodic meter readings.

It is noted that while the above describes example 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 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 procedures 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 such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable 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 processors 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 (ASIC) , gate level circuits and processors based on 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 functions and/or method procedures previously described. That circuitry may be provided in the network entity and/or in the communications 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 (such as implementations in only analogue and/or digital circuitry) ;

(b) combinations of hardware circuits and software, such as: (i) a combination of analogue and/or digital hardware circuit (s) with software/firmware and (ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause the communications device and/or device and/or server and/or network entity to perform the various functions previously described; and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example integrated device.

It is noted that whilst embodiments have been described in relation to certain architectures, similar principles can be applied to other systems. Therefore, although certain embodiments were described above by way of example with reference to certain exemplifying architectures for wireless networks, technologies standards, and protocols, the herein described features may be applied to any other suitable forms of systems, architectures and devices than those illustrated and described in detail in the above examples. It is also noted that different combinations of 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

A method comprising:

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

acquiring information associating pre-configured resources to the indicated random access resources; and

determining occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources.
A method comprising:

associating pre-configured resources to random access resources associated with at least one synchronization signal block;

sending information of the association of the pre-configured resources to the indicated random access occasions; and

monitoring occasions for small data transmission associated with the at least one synchronization signal block according to the information of the association of the pre-configured resources to the random access resources.
The method according to claim 1 or 2, comprising utilizing at least one of said occasions for small data transmission for a small data transmission by a terminal device and/or reception of a small data transmission from a terminal device.
The method according to claim 3, wherein the terminal device is in an inactive radio resource control state.
The method according to any preceding claim, 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.
The method according to any preceding claim, wherein the synchronization signal block is provided by analogue beamforming.
The method according to any preceding claim, wherein Frequency Range 2 according to 3GPP specifications or above is used for the carrier for small data transmissions.
The method according to any preceding claim, comprising configuring at least one random access slot or random access occasion mapped to a synchronization signal block beam to serve as a time anchor for the pre-configured resources.
The method according to any preceding claim, wherein the information comprises an indication of an offset in time domain between the pre-configured resources and the associated random access resources.
The method according to any of claims 1 -8, wherein the random access resources and the pre-configured resources overlap in time.
The method according to any preceding claim, wherein the information comprises an indication of an offset in frequency domain between the pre-configured resources and the associated random access resources.
The method according to any preceding claim, wherein the information comprises an indication of a ratio between occasions that can be used for small data transmissions and occasions that cannot be used for small data transmission.
The method according to claim 12, wherein the ratio is determined dynamically based on the type of data to be transmitted.
The method according to any preceding claim, wherein the information associating the pre-configured resources to the indicated random access resources is provided in a configured grant for a small data transmission configuration in a radio resource control release message or a system information block message.
The method according to any preceding claim, wherein the information associating the pre-configured resources to the indicated random access resources is provided via explicit signalling.
The method according to any of claims 1 to 14, wherein the information associating the pre-configured resources to the indicated random access resources is provided via implicit signalling.
The method according to any preceding claim, wherein transmission occasions associated with a synchronization signal block are set based on the random access occasions associated with the synchronization signal block.
The method according to any preceding claim, comprising:

determining that the occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources cannot be used for a small data transmission, and

in response switching to a random access procedure for the transmission of the small data transmission.
An apparatus for a communication device, the apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to:

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

acquire information associating pre-configured resources to the indicated random access resources; and

determine occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources.
An apparatus for a communication network, the apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to:

associate pre-configured resources to random access resources associated with at least one synchronization signal block;

send information of the association of the pre-configured resources to the indicated random access occasions; and

monitor occasions for small data transmission associated with the at least one synchronization signal block according to the information of the association of the pre-configured resources to the random access resources.
The apparatus according to claim 19 or 20, configured to utilize at least one of said occasions for small data transmission for transmission and/or reception of a small data transmission.
The apparatus according to any of claims 19 to 21, wherein the association of the pre-configured resources to the random access resources for small data transmission is provided for a device in an inactive radio resource control state.
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.
The apparatus according to any of claims 19 to 23, wherein the synchronization signal block is provided by analogue beamforming.
The apparatus according to any of claims 19 to 24, configured to use Frequency Range 2 according to 3GPP specifications or above for small data transmissions carrier.
The apparatus according to 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 resources.
The apparatus according to any of claims 19 to 26, wherein the information of the association of the pre-configured resources to the indicated random access occasions comprises an indication of an offset in time domain between the pre-configured resources and the associated random access resources.
The apparatus according to any of claims 19 to 26, wherein the random access resources and the pre-configured resources overlap in time.
The apparatus according to any of claims 19 to 28, wherein the information of the association of the pre-configured resources to the indicated random access occasions comprises an indication of an offset in frequency domain between the pre-configured resources and the associated random access resources.
The apparatus according to any of claims 19 to 29, wherein the information of the association of the pre-configured resources to the indicated random access occasions comprises an indication of a ratio between occasions that can be used for small data transmissions and occasions that cannot be used for small data transmission.
The apparatus according to claim 30, configured to use a dynamic ratio based on the type of data to be transmitted.
The apparatus according to any of claims 19 to 31, configured for communication of the information associating the pre-configured resources to the indicated random access resources in a configured grant for a small data transmission configuration in a radio resource control release message and/or a system information block message.
The apparatus according to any of claims 19 to 32, configured for explicit signalling of the information associating the pre-configured resources to the indicated random access resources.
The apparatus according to any of claims 19 to 32, configured for implicit signalling of the information associating the pre-configured resources to the indicated random access resources.
The apparatus according to any of claims 19 to 34, wherein transmission occasions associated with a synchronization signal block are set based on the random access occasions associated with the synchronization signal block.
The apparatus according to any of claims 19 to 35, configured to determine that the occasions for small data transmission associated with the at least one synchronization signal block based on the information associating the pre-configured resources to the indicated random access resources cannot be used for a small data transmission, and in response to switch to a random access procedure for the transmission of the small data transmission.
A computer readable media comprising program code for causing a processor to perform instructions for a method as claimed in any of claims 1 to 18.