EP4278830A1

EP4278830A1 - Radio network node, user equipment and methods performed therein

Info

Publication number: EP4278830A1
Application number: EP22701733.2A
Authority: EP
Inventors: Kazuyoshi Uesaka; Muhammad Ali Kazmi; Santhan THANGARASA; Andreas HÖGLUND; Luca FELTRIN; Se-171 47 CHRISTOFFERSSON
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2021-01-14
Filing date: 2022-01-12
Publication date: 2023-11-22
Also published as: WO2022154720A1

Abstract

Embodiments herein relate, for example, to a method performed by a UE (10) for handling communication in a wireless communication network. The UE (10) is configured to perform a number of SDT procedures, each SDT procedure using a respective RA procedure type. The UE (10) performs a 5SDT according to one SDT procedure out of the number of SDT procedures, selected based on a size of an UL message.

Description

RADIO NETWORK NODE, USER EQUIPMENT AND METHODS PERFORMED THEREIN

TECHNICAL FIELD

Embodiments herein relate to a radio network node, a user equipment (UE) and methods performed therein regarding wireless communication. Furthermore, a computer program and a computer readable storage medium are also provided herein. In particular, embodiments herein relate to handling small data transmissions (SDT) in a wireless communications network.

BACKGROUND

In a typical wireless communications network, UEs, also known as wireless communication devices, mobile stations, stations (STA) and/or wireless devices, communicate via a Radio Access Network (RAN) with one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cells, with each service area or cell being served by a radio network node such as an access node e.g. a Wi-Fi access point or a radio base station (RBS), which in some networks may also be called, for example, a NodeB, a gNodeB, or an eNodeB. The service area or cell is a geographical area where radio coverage is provided by the radio network node. The radio network node operates on radio frequencies to communicate over an air interface with the UEs within range of the radio network node. The radio network node communicates over a downlink (DL) to the UE and the UE communicates over an uplink (UL) to the radio network node.

A Universal Mobile Telecommunications System (UMTS) is a third generation (3G) telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High-Speed Packet Access (HSPA) for communication with user equipment. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for present and future generation networks and investigate, e.g., enhanced data rate and radio capacity. In some RANs, e.g., as in UMTS, several radio network nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural radio network nodes connected thereto. The RNCs are typically connected to one or more core networks.

Specifications for the Evolved Packet System (EPS) have been completed within the 3GPP and coming 3GPP releases, such as New Radio (NR), are worked on. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long-Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E- UTRAN/LTE is a 3GPP radio access technology wherein the radio network nodes are directly connected to the EPC core network. As such, the RAN of an EPS has an essentially “flat” architecture comprising radio network nodes connected directly to one or more core networks.

With the emerging 5G technologies such as new radio (NR), the use of very many transmit- and receive-antenna elements may be of great interest as it makes it possible to utilize beamforming, such as transmit-side and receive-side beamforming. Transmit-side beamforming means that the transmitter can amplify the transmitted signals in a selected direction or directions, while suppressing the transmitted signals in other directions. Similarly, on the receive-side, a receiver can amplify signals from a selected direction or directions, while suppressing unwanted signals from other directions.

UEs access networks by performing a random access (RA) procedure. There are different types of RA, so called RA procedure types.

A 4-step RA type has been used in 4G LTE and is also the baseline for 5G NR. The principle of this procedure in NR is shown in Fig. 1.

Step 1 : Preamble transmission. The UE randomly selects a RA preamble such as a PREAMBLE_INDEX corresponding to a selected synchronization signal (SS)/physical broadcast channel (PBCH) block, transmit the preamble on the physical random access channel (PRACH) occasion mapped by the selected SS/PBCH block. When the gNB detects the preamble, the gNB estimates a Timing advance (TA) the UE should use in order to obtain UL synchronization at the gNB.

Step 2: RA response (RAR). The gNB sends a RAR including the TA, the temporary identifier such as temporary cell (TC)-radio network temporary identifier (RNTI) to be used by the UE, a Random Access Preamble identifier that matches the transmitted PREAM BLEJN DEX and a grant for Msg3. The UE expects the RAR and thus, monitors physical downlink control channel (PDCCH) addressed to RA-RNTI to receive the RAR message from the gNB until the configured RAR window (ra-ResponseWindow) has expired or until the RAR has been successfully received. From 3GPP TS38.321 v.16.0.0: “The MAC entity may stop ra-ResponseWindow, and hence monitoring for RAR(s), after successful reception of a RAR containing Random Access Preamble identifiers that matches the transmitted PREAM BLE_INDEX“.

Step 3: “Msg3” (UE ID or UE-specific cell (C)-RNTI). In Msg3 the UE transmits its identifier (UE ID, or more exactly the initial part of the 5G- Temporary Mobile Subscriber Identity (TMSI)) for initial access or if it is already in RRC_CONNECTED or RRCJNACTIVE mode and needs to e.g. re-synchronize, its UE-specific RNTI.

If the gNB cannot decode Msg3 at the granted UL resources, it may send a downlink control information (DCI) addressed to TC-RNTI for retransmission of Msg3. Hybrid access repeat request (HARQ) retransmission is requested until the UEs restart the random access procedure from step 1 after reaching the maximum number of HARQ retransmissions or until Msg3 can be successfully received by the gNB.

Step 4: “Msg4”, contention resolution. In Msg4 the gNB responds by acknowledging the UE ID or C-RNTI. The Msg4 gives contention resolution, i.e. , only one UE ID or C-RNTI will be sent even if several UEs have used the same preamble, and the same grant for Msg3 transmission, simultaneously.

For Msg4 reception, the UE monitors TC-RNTI, if it transmitted its UE ID in Msg3, or C-RNTI, if it transmitted its C-RNTI in Msg3.

A 2-step RA type gives much shorter latency than the ordinary 4-step RA. In the 2- step RA the preamble and a message corresponding to Msg3, msgA physical uplingk shared channel (PUSCH), in the 4-step RA can, depending on configuration, be transmitted in two subsequent slots. The msgA PUSCH is sent on a resource dedicated to the specific preamble. The 2-step RA procedure is depicted in Fig. 2.

Upon successful reception of the msgA, the gNB will respond with a msgB. The msgB may be either a “successRAR”, “fallbackRAR or “Back off’. The content of msgB has been agreed as seen below. It is noted in particular that fallbackRAR provides a grant for a Msg3 PUSCH that identifies resources in which the UE should transmit the PUSCH, as well as other information.

Note: The notations “msgA” and “MsgA” are used interchangeably herein to denote message A. Similarly, the notations “msgB” and “MsgB” are used interchangeably herein to denote message B. The possibility to replace the 4-step message exchange by a 2-step message exchange would lead to reduced RA latency. On the other hand, the 2-step RA will consume more resources since it uses contention-based transmission of the data. This means that the resources that are configured for the data transmission may often be unused. Another difference is that 2-step RA operated without a TA since there is no feedback from gNB on how to adjust the uplink synchronization before the data payload is transmitted in MsgA PLISCH. Effectively TA is zero for 2-step RA and therefore the solution is restricted to use in cell of smaller size, whereas 4-step RA can operate in any cell size.

If both the 4-step and 2-step RA are configured in a cell on shared PRACH resources, and for the UE, the UE will choose its preamble from one specific set if the condition of 4-step RA is met, and from another set if the condition of 2-step RA, based on the measured reference signal received power (RSRP), is met. Hence a preamble partition is done to distinguish between 4-step and 2-step RA when shared PRACH resources are used. Alternatively, the PRACH configurations are different for the 2-step and 4-step RA procedure, in which case it can be deduced from where the preamble transmission is done if the UE is doing a 2-step or 4-step procedure.

In 3GPP Rel-162-step RA type procedure, UEs are informed of the potential timefrequency resources where they may transmit MsgA PRACH and MsgA PUSCH via higher layer signaling from the network. PRACH is transmitted in periodically recurring RACH occasions (RO), while PUSCH is transmitted in periodically recurring PUSCH occasions (PO). PUSCH occasions are described in MsgA PUSCH configurations provided by higher layer signaling. Each MsgA PUSCH configuration defines a starting time of the PUSCH occasions which is measured from the start of a corresponding RACH occasion. Multiple PUSCH occasions may be multiplexed in time and frequency in a MsgA PUSCH configuration, where POs in an orthogonal frequency division multiplexing (OFDM) symbol occupy a given number of physical resource blocks (PRB) and are adjacent in frequency, and where POs occupy ‘L’ contiguous OFDM symbols. POs multiplexed in time in a MsgA PUSCH configuration may be separated by a configured gap ‘G’ symbols long. The start of the first occupied OFDM symbol in a PUSCH slot is indicated via a start and length indicator value (SLIV). The MsgA PUSCH configuration may comprise multiple contiguous PUSCH slots, each slot containing the same number of POs. The start of the first PRB relative to the first PRB in a bandwidth part (BWP) is also given by the MsgA PUSCH configuration. Moreover, the modulation and coding scheme (MCS) for MsgA PUSCH is also given by the MsgA PUSCH configuration. Each PRACH preamble maps to a PLISCH occasion and a demodulation reference signal (DM RS) port and/or a DM RS port-scrambling sequence combination according to a procedure given in 3GPP TS 38.213 v.16.0.0. This mapping allows a gNB to uniquely determine the location of the associated PLISCH in time and frequency as well as the DMRS port and/or scrambling from the preamble selected by the UE.

The PRACH preambles also map to associated synchronization signal blocks (SSB). The SSB to preamble association combined with the preamble to PLISCH association allow a PO to be associated with a RACH preamble. This indirect preamble to PLISCH mapping may be used to allow a gNB using analog beamforming to receive a MsgA PLISCH with the same beam that it uses to receive the MsgA RACH preamble.

Small data transmission (SDT): NR supports RRCJNACTIVE state and UEs with infrequent, i.e., periodic and/or aperiodic, data transmission, such as SDT, are generally maintained by the network not in RRCJDLE but in the RRCJNACTIVE state. Until Rel- 16, the RRCJNACTIVE state doesn’t support data transmission. Hence, the UE has to resume the connection, i.e., move to RRC_CONNECTED state, for any DL data reception and UL data transmission. Connection setup and subsequently release to RRCJNACTIVE state happens for each data transmission. This results in unnecessary power consumption and signaling overhead. For this reason, support for UE transmission in RRCJNACTIVE state using random access procedure is introduced in Rel-17. SDT is a procedure to transmit UL data from UE in RRCJNACTIVE state. SDT is performed with either random access or configured grant (CG). From here on, mainly the former, RA- based SDT will be discussed. The case in which the UE transmits UL data with random access can use both 4-step RA type and 2-step RA type. If the UE uses 4-step RA type for the SDT procedure, then the UE transmits the UL data in the Msg3. If the UE uses 2- step RA type for the SDT procedure, then the UE transmits UL data in the MsgA.

Transmissions of small data can take place in low activity states such as RRCJNACTIVE state instead of setting up dedicated communication link. This makes data transmissions faster and also reduces the signaling overheads associated with setting up dedicated link for every small size of packets. The UL data volume that is transmitted using SDT can vary, e.g., sometimes it can be quite small compared with the threshold to select SDT.

When the gNB configures 4-step RA type and 2-step RA type for SDT, the UE needs to select one of RA types, i.e., 4-step RA type or 2-step RA type, for the UL data transmissions. According to the existing procedure, the measured RSRP is the only criterion to select the RA type. Typically, the UE may select 2-step RA type when the measured RSRP is above a certain threshold, e.g., msgA-RSRP-Threshold. Otherwise, it should select 4-step RA.

SUMMARY

As part of developing embodiments herein one or more problems have been identified. A problem with current RA-type selection procedure is that the selection takes only the radio conditions, e.g., pathloss, into account without any consideration to the traffic characteristics. Since the RA-based SDT traffic is highly unpredictable and variable, using a particular RA-type for SDT data based only on signal strength is not suitable. This will lead to sub-optimal performance of SDT based on RA type, leading to increase in delay, overheads and wastage of resources. This will therefore negate the benefit of using RA-based SDT data transmission. Another problem is that the UE behaviour is not defined on how to transmit the SDT when the UE is configured with both 2-step RA and 4- step RA in the standard specification. Therefore, herein it is studied possible enhancement to address the issue.

An object herein is to provide a mechanism to handle communication of small data transmission in an efficient manner in the wireless communications network.

According to an aspect the object is achieved, according to embodiments herein, by providing a method performed by a UE for handling communication in a wireless communication network. The UE is configured to perform a number of SDT procedures, each SDT procedure using a respective RA procedure type, e.g., a 2-step SDT and a 4- step SDT procedure. The UE performs an SDT according to one SDT procedure out of the number of SDT procedures, selected based on a size of an UL message.

According to an aspect the object is achieved, according to embodiments herein, by providing a method performed by a radio network node for handling communication in a wireless communications network. The radio network node configures the UE to perform SDT procedures, wherein each SDT procedure is using a respective random access procedure type, e.g. a 2-step SDT and a 4-step SDT procedure based on the RA type, and wherein a SDT procedure to use is selected based on a size of an UL message.

According to an aspect the object is achieved, according to embodiments herein, by providing a UE and a radio network node configured to perform the methods herein, respectively.

Thus, it is herein provided a radio network node for handling communication in a wireless communications network. The radio network node is configured to configure the UE to perform SDT procedures, wherein each SDT procedure is using a respective random access procedure type, e.g. a 2-step SDT and a 4-step SDT procedure based on the RA type, and wherein a SDT procedure to use is selected based on a size of an UL message.

Furthermore, it is herein provided a UE for handling communication in a wireless communication network. The UE is configured to perform a number of SDT procedures, each SDT procedure using a respective RA procedure type, e.g., a 2-step SDT and a 4- step SDT procedure. The UE is further configured to perform an SDT according to one SDT procedure out of the number of SDT procedures, selected based on a size of an UL message.

It is furthermore provided herein a computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out the method above, as performed by the UE or the radio network node, respectively. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the method above, as performed by the UE or the radio network node, respectively.

Embodiments herein disclose procedures for the UE to select SDT of different RA procedures exemplified and denoted as a 2-step SDT procedure and a 4-step SDT procedure. Amount of UL resources for, e.g., 2-step RA allocated by the radio network node can be smaller than the amount of UL resources required for SDT using 4-step SDT procedure. This means that the radio network node may optimize the UL resource allocation for 2-step RA type for SDT, thereby enabling an efficient use of resources when communicating in the wireless communication network. Furthermore, the UE can transmit smaller UL data faster and with less power consumption. Thus, it is herein disclosed a solution to handle communication of small data transmission in an efficient manner in the wireless communications network.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail in relation to the enclosed drawings, in which:

Fig. 1 shows a 4-step RA procedure according to prior art;

Fig. 2 shows a 2-step RA procedure according to prior art; Fig. 3 shows an overview depicting a wireless communications network according to embodiments herein;

Fig. 4 shows a combined signalling scheme and flowchart depicting embodiments herein;

Fig. 5 shows a flowchart depicting a method performed by a UE according to embodiments herein;

Fig. 6 shows a flowchart depicting a method performed by a radio network node according to embodiments herein;

Fig. 7 shows a flowchart depicting a method performed by a UE according to some embodiments herein;

Fig. 8 shows a flowchart depicting a method performed by a UE according to some embodiments herein;

Figs. 9a-9b show block diagrams depicting embodiments of a UE according to embodiments herein;

Figs. 10a-10b show block diagrams depicting embodiments of a radio network node according to embodiments herein;

Fig. 11 schematically illustrates a telecommunication network connected via an intermediate network to a host computer;

Fig. 12 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection; and

Figs. 13-16 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment.

DETAILED DESCRIPTION

Embodiments herein relate to wireless communications networks in general. Fig. 3 is a schematic overview depicting a wireless communications network 1. The wireless communications network 1 comprises one or more RANs and one or more CNs. The wireless communications network 1 may use one or a number of different technologies. Embodiments herein relate to recent technology trends that are of particular interest in a New Radio (NR) context, however, embodiments are also applicable in further development of existing wireless communications systems such as e.g. LTE WCDMA.

In the wireless communications network 1, a UE 10 exemplified herein as a wireless device such as a mobile station, a non-access point (non-AP) station (STA), a STA and/or a wireless terminal, is comprised communicating via e.g. one or more Access Networks (AN), e.g. RAN, to one or more CNs. It should be understood by the skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communications terminal, user equipment, narrowband internet of things (NB-loT) device, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station capable of communicating using radio communication with a radio network node within an area served by the radio network node.

The wireless communications network 1 comprises a first radio network node 12 or just radio network node 12, providing radio coverage over a geographical area, a first service area 11 or first cell, of a first radio access technology (RAT), such as NR, LTE, or similar. The radio network node 12 may be a transmission and reception point such as an access node, an access controller, a base station, e.g. a radio base station such as a gNodeB (gNB), an evolved Node B (eNB, eNode B), a NodeB, a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA), a transmission arrangement of a radio base station, a stand-alone access point or any other network unit or node capable of communicating with a wireless device within the area served by the radio network node depending e.g. on the first radio access technology and terminology used. The radio network node may be referred to as a serving radio network node wherein the service area may be referred to as a serving cell, and the serving network node communicates with the wireless device in form of DL transmissions to the wireless device and UL transmissions from the wireless device. It should be noted that a service area may be denoted as cell, beam, beam group or similar to define an area of radio coverage.

A mechanism is herein provided for performing an SDT from the UE 10 to the radio network node 12. The UE 10 performs a small data transmission according to one small data transmission procedure out of a number configured small data transmission procedures, selected based on a size of an UL message. The term small data or STD may correspond to any data packet transmitted by a UE with a size below certain threshold. The term small data or STD may also be called as simply data or data packet. The data packet may correspond to any of: packet data unit (PDU), payload, data block, transport block, number of radio resources carrying the data packet etc. Examples of radio resources are number of resource elements, number of resource blocks etc. The data size may be expressed in terms of one or more of bits, bytes, octets, number of data packets per transmission etc. Fig. 4 is a combined signalling scheme and flowchart depicting embodiments herein.

Action 401. The radio network node 12 may configure the UE 10 with a number of SDT procedures, each being associated with a RA procedure type. For example, the radio network node 12 may configure the UE 10 to use a 4-step SDT procedure and a 2-step SDT procedure, also referred to herein as 4-step RA for SDT and 2-step RA for SDT. The radio network node 12 may further configure the UE 10 with parameters, thresholds and the like to determine when to use which SDT procedure, e.g., thresholds for UL message size, signal strength or quality, and/or parameters for configuration, e.g., a table for determining a threshold or parameters to derive such. It should be noted that the UE 10 may be preconfigured with the capability of using the number of SDT procedures and/or when to use the different SDT procedures, for example, by one or more predefined rules e.g. if Ms < HSDT, then UE 10 uses the SDT procedure, otherwise the UE 10 uses the legacy UL data transmission, and/or if RSRP > RSRPSDT, then the UE 10 uses the SDT procedure, otherwise the UE 10 uses the legacy UL data transmission, etc. The specific parameter settings, such as HSDT, RSRPSDT, may be given in system information; and/or a predefined rule to derive HRSRp-Data, parameters to derive such HRSRp-Data or a table for determining thresholds.

Action 402. The UE 10 may select an SDT procedure to use based on the size of an UL message. The SDT procedure may further be selected based on signal strength or quality such as RSRP and/or reference signal received quality (RSRQ). The UE 10 may thus select SDT procedure based on a threshold of an UL message size. For example, if the UL message size Ms, e.g., transport block size (TBS), is smaller than or equal to a threshold, i.e. , Ms s HM, the UE 10 may use a SDT procedure using a 2-step RA type, otherwise the UE 10 may use a SDT procedure using a 4-step RA type. Thus, if Ms > HM, the UE 10 uses a SDT procedure using a 4-step RA type. Additionally or alternatively, if the measured RSRP is larger than a threshold HRSRP, i.e., RSRP > HRSRP, the UE 10 uses a SDT procedure using a 2-step RA type, otherwise the UE 10 uses a SDT procedure using a 4-step RA type. The threshold for RSRP may be a threshold HRSRp-Data being a function of data payload to be transmitted from the UE 10. For example, larger payload would result in a HRSRp-Data that is higher than a HRSRp-Data for a smaller payload, such that 2-step SDT procedure would be selected for SDT in a larger part of the cell compared to 4-step SDT.

Action 403. The UE 10 performs an SDT using the selected SDT procedure. Embodiments herein use smaller amount of UL resources for 2-step RA allocated by the radio network node 12 than amount of UL resources required for SDT. This means that the radio network node 12 may optimize the UL resource allocation, for example, for 2-step RA type for SDT. Furthermore, the UE 10 can transmit smaller UL data faster when the predefined rule is fulfilled and with less power consumption.

The method actions performed by the UE 10 for handling communication in the wireless communications network 1 according to embodiments will now be described with reference to a flowchart depicted in Fig. 5. The actions do not have to be taken in the order stated below but may be taken in any suitable order. Dashed boxes indicate optional features. The UE 10 is configured to perform a number of SDT procedures, each SDT procedure using a respective RA procedure type.

Action 501. The UE 10 may be configured by the radio network node 12 or be preconfigured with the number of SDT procedures, e.g., a 2-step SDT procedure and 4- step SDT procedure, each being associated with a respective RA procedure type. The UE 10 may be configured with a preconfigured number of SDT procedures. The 2-step SDT procedure meaning using a 2-step RA procedure for SDT and 4-step SDT procedure meaning using a 4-step RA procedure for SDT. Thus, the number of SDT procedures may comprise a 2-step SDT procedure and a 4-step SDT procedure based on the RA procedure type. The UE 10 may be configured with parameters, thresholds and the like to determine when to use which SDT procedure, e.g. thresholds for UL message size, signal strength or quality, and/or parameters for configuration, e.g. a table for determining a threshold or parameters to derive such.

Action 502. The UE 10 may select the one SDT procedure to use based on the size of the UL message. The UE 10 may further select the one SDT procedure out of the number of SDT procedures further based on the signal strength or quality such as RSRP and/or RSRQ. The UE 10 may thus select the one SDT procedure to use based on the threshold for size of an UL message. The UE 10 may further select the one SDT procedure to use based on the threshold of the RSRP. The threshold may be defined by a function of data payload to be transmitted from the UE 10.

Action 503. The UE 10 performs the SDT according to one SDT procedure out of the number SDT procedures, selected based on the size of the UL message. Thus, the UE 10 performs the SDT according to the selected SDT procedure. The method actions performed by the radio network node 12 for handling communication in the wireless communications network according to embodiments will now be described with reference to a flowchart depicted in Fig. 6. The actions do not have to be taken in the order stated below but may be taken in any suitable order. Dashed boxes indicate optional features.

Action 601. The radio network node 12 configures the UE 10 to perform SDT procedures, wherein each SDT procedure is using a respective random access procedure type, and wherein a SDT procedure to use is selected based on the size of the UL message. The SDT procedure used by the UE 10 may further be selected based on the signal strength or quality. The radio network node 12 may configure the UE 10 with a number of SDT procedures, e.g., a 2-step SDT procedure and 4-step SDT procedure, each being associated with a RA procedure type. The radio network node 12 may configure the UE 10 with a parameter and/or threshold for UL message size, signal strength or quality, and/or parameter for configuration to determine when to use which SDT procedure. The radio network node may configure the UE 10 with parameters, thresholds and/or the like to determine when to use which SDT procedure, e.g., thresholds for UL message size, signal strength or quality, and/or parameters for configuration, e.g., a table for determining a threshold or parameters to derive such.

Action 602. The radio network node 12 may receive data using one SDT procedure selected by the UE 10 based on the size of the UL message. The radio network node 12 may receive an SDT using an SDT procedure selected by the UE 10 based on size of UL message and/or signal strength or quality.

Thus, embodiments herein disclose a scenario that comprises at least one UE, e.g. the UE 10, which is operating in a first cell, e.g., cell 11 , served by the radio network node 12 also denoted as NW1. The network, such as the radio network node 12, configures that the UE 10 may use the SDT procedure. The network also configures 4- step RA type and 2-step RA type for SDT procedure. The radio network node 12 may also configure the UE with a signal strength threshold, e.g. RSRP threshold, for selecting between RA types.

In legacy RA procedures the message sizes Msg3 and MsgA in 4-step RA and 2- step RA respectively are almost fixed and relatively small. But the data/message size for SDT traffic can vary and the radio network node 12 cannot predict the data size in advance. For 2-step RA type, unlike 4-step RA type, the radio network node 12 needs to allocate the UL resources, i.e. , PRBs, and configure MCS in advance. This means, to be able to transmit the same amount of data with 2-step RA as in 4-step RA, the radio network node needs to reserve same or large amount of UL data resources beforehand. This may result in waste of network resources as the preserved resources may not always be used.

The steps involved in a first embodiment of selecting the RA type for SDT also referred to above as SDT procedure, are shown in the flowchart in Fig. 7.

Action 710. The UE higher layers trigger the UE 10 to transmit UL data. This may be triggered for example upon arrival of data in the UE buffer. At this step, transmission of data may take place using the SDT RA procedure or using the legacy procedures, i.e., using dedicated communication link in RRC_CONNECTED state. In the latter, i.e., legacy case, the UE 10 establishes a connection with the radio network node 12 by sending a RA to the radio network node 12 and sends data using the assigned resources after the connection is established.

Action 720: When the UL message is available at the UE 10, the UE 10 decides whether the UL data is transmitted with a SDT procedure or legacy UL data transmission according to the message size (Ms) e.g. based on the comparison between Ms and a message threshold, also referred to as a SDT threshold. For example, if the UL message size (Ms) is smaller than or equal to a configurable or predefined threshold (HSDT), then the UE 10 may use the SDT procedure. Otherwise, the UE 10 proceeds to Action 725 where the transmission is carried out using the legacy UL data transmission procedure using dedicated communication link. Ms can be expressed in terms of transport block size, coded bits, payload, block size, data unit size, etc. The SDT threshold HSDT can be set based on different factors such as SDT traffic type indicating how frequent the SDT data are expected to be transmitted, the expected size of the SDT data, the criticality of the SDT data, the priority of the SDT data, transmission parameters, including modulation scheme, etc.

Action 730: If the UE 10 selects to perform an SDT procedure in action 720, then the UE 10 further selects one of the at least two RA types for SDT, i.e., SDT with 4-step RA type called 4-step SDT procedure or SDT with 2-step RA type denoted as 2-step SDT procedure, according to the UL message size (Ms). The UE 10 selects thus the RA type for transmitting the SDT data based on the UL message size (Ms). In one example the selection of the RA type is based on the comparison between Ms and a message threshold (HM). The message threshold, HM, can be configurable or predefined, indicating the maximum data size that can be transmitted using the 2-step RA procedure for the SDT.

For example, if the UL message size is smaller than or equal to the threshold (HM), i.e. , Ms s HM, then the UE 10 selects 2-step RA type for SDT transmission and in this case the UE 10 follows the steps associated with the 2-step RA procedure (Action 740). Otherwise (i.e. if Ms > HM), then the UE 10 selects 4-step RA type for SDT and in this case the UE 10 follows the steps associated with the 4-step RA procedure (Action 745). In the former case, i.e., Action 740, the data is transmitted over MSGA and in the latter case, i.e., Action 745, the data is transmitted using resources in MSG3 as described above.

An advantage of selecting the RA-type based on the message size is that SDT transmission becomes faster compared to not having such selection rule since the procedure is adapted to the size of the UL data to be transmitted.

The threshold HM can be set based on different factors such as SDT traffic type indicating how frequent the SDT data are expected to be transmitted, the expected size of the SDT data, the criticality of the SDT data, etc.

The thresholds, HSDT and HM, can be related to each other by an expression or a function. One example of a relation between HSDT and HM can be expressed as follows:

HM < HSDT (1)

Table 1 is an example of the relation of threshold HM and selected RA types in Action 730. Such relations can be pre-defined. In the relation/table, the threshold HM can be pre-defined, the threshold is configured by the network, or, the multiple thresholds are pre-defined but one of it is configured to be used by the UE 10.

Table 1 : Example of the relation between UL message size and selected

RA type.

In another embodiment the RA type selection, also referred to as the SDT procedure selection, may be based on RSRP and SDT message size. In this embodiment when the UE 10 decides to use RA for SDT transmission then the UE 10 selects one of the two RA types (2-step and 4-step RA) based on: a relation or comparison between a message size (Ms) for SDT transmission and a threshold (HM), and a relation or comparison between a signal strength, e.g., RSRP, synchronization signal (SS)-RSRP etc, measured in a cell and a signal strength threshold (HRSRP). The UE 10 may perform the comparisons between Ms and HM and RSRP and HRSRP in any order for selecting the RA type for SDT transmission.

The actions involved in this embodiment of selecting the RA type for SDT is shown in the flowchart in Fig.8.

Action 810. The UE higher layers trigger the UE 10 to transmit UL data. This may be triggered for example upon arrival of data in the UE buffer. At this step, transmission of data may take place using the SDT RA procedure or using the legacy procedures, i.e. using dedicated communication link in RRC_CONNECTED state.

Action 820. When the UL message is available at the UE 10, then the UE 10 may decide that the UL data is transmitted with SDT procedure or legacy UL data transmission according to the message size (Ms). For example, if the UL message size is smaller than or equal to a configurable or predefined threshold (HSDT), then the UE 10 may use the SDT procedure. If not, the UE 10 may proceed to Action 825 where the transmission is carried out using the legacy UL data transmission procedure using dedicated communication link.

Action 830. If the UE 10 selects the SDT procedure in Action 820, then the UE 10 selects RA type for SDT, i.e., 4-step RA type or 2-step RA type for the SDT, according to the UE message size (Ms). In this step, the UE 10 selects the RA type for transmitting the SDT data based on the UL message size (Ms). In one example, Ms is compared to a threshold HM, which is configurable or predefined threshold indicating the maximum data size that can be transmitted using the 2-step RA procedure.

The comparisons between Ms and HM, and RSRP and RSRP threshold (HRSRP) can be done in different order or sequence as explained with examples below but outcome is the same as shown in table 2.

Action 840. In one example of this action, the UE 10 checks that the measured RSRP level fulfills the condition of 2-step RA type. This is done by comparing RSRP and RSRP threshold (HRSRP). The RSRP is measured by the UE 10 in a serving cell, e.g., on SSB of the serving cell associated to RA used for SDT. For example, if the measured RSRP level is less than or equal to the RSRP threshold, i.e., RSRP < HRSRP, then the UE 10 uses 4-step RA type for SDT regardless of the relation between Ms and HM and follows the steps associated with the 4-step RA procedure (Action 855) for SDT transmission. Otherwise, if the measured RSRP level exceeds the RSRP threshold, i.e., RSRP > HRSRP, then the UE 10 may use either 2-step RA type or 4-step RA type for SDT transmission. In this case, i.e., when RSRP > HRSRP, the UE 10 further selects between 2-step RA type and 4-step RA type for the SDT based on the comparison between Ms and HM as follows:

For example, if the UL message size is smaller than or equal to the threshold (HM), i.e., Ms s HM, then the UE 10 selects 2-step RA type for SDT and the UE 10 follows the steps associated with the 2-step RA procedure (Action 850).

Otherwise, i.e., if Ms > HM, the UE 10 selects 4-step RA type for SDT and follows the steps associated with the 4-step RA procedure (Action 855).

In another example of this step, the UE 10 compares the UL message size (Ms) with the threshold (HM), Action 830. The UE 10 further compares the measured RSRP with RSRP threshold (HRSRP), Action 840:

If the UL message size is smaller than or equal to the threshold (HM), i.e., Ms < HM, and RSRP is greater than RSRP threshold (RSRP > HRSRP) then the UE 10 selects 2-step RA type for SDT transmission, Action 850.

If the UL message size is smaller than or equal to the threshold (HM), i.e., Ms < HM, but RSRP is less than or equal to RSRP threshold (RSRP < HRSRP) then the UE 10 selects 4-step RA type for SDT transmission, Action 855.

If the UL message size is greater than the threshold (HM), MS > HM then the UE 10 selects 4-step RA type regardless of the relation between RSRP and RSRP threshold, Action 855.

Table 2 show an example of the relation of thresholds (HM, HRSRP) and selected RA types in Actions 830 and 840. Such relations can be pre-defined. In the relation/table, the threshold set (HM, HRSRP) can be pre-defined, the threshold set is configured by the network, or, the multiple threshold sets are pre-defined but one of it is configured to be used by the UE 10.

Table 2: Example of the relation between UL message size, measured RSRP level, and selected RA type.

Alternatively or additionally, the RA selection may be based on RSRP thresholds that depends on the SDT message size. In this embodiment when the UE 10 decides to use RA for SDT transmission then the UE 10 selects one of the two RA types (2-step and 4-step RA) based on: a relation or comparison between a signal strength, e.g., RSRP, SS-RSRP etc, measured in a cell and a signal strength threshold (HRSRP-A, HRSRP-B) where they choice of threshold depend on the UE message size (Ms).

In one example, if the Ms is small enough for the data to fit in the TBS corresponding to preamble group A for 2-step, the UE 10 compares the signal strength to the lower RSRP threshold (HRSRP-A). If the signal strength is above the lower RSRP threshold the UE 10 selects 2-step RA for SDT. If the signal strength is equal or below the lower RSRP threshold the UE 10 selects 4-step RA for SDT.

If the Ms is small enough for the data to fit in the TBS corresponding to preamble group B, but not preamble group A, the UE 10 compares the signal strength to the higher RSRP threshold (HRSRP-B). If the signal strength is above the higher RSRP threshold the UE 10 selects 2-step RA for SDT. If the signal strength is equal or below the higher RSRP threshold the UE 10 selects 4-step RA for SDT.

If the Ms is not small enough for the data to fit in the TBS corresponding to preamble group B the UE may be configured to either:

1. Select 4-step RA, or

2. Select 2-step if the signal strength is above the higher RSRP threshold (HRSRP-B ).

Figs. 9a and 9b are block diagrams depicting the UE 10 in two embodiments for handling communication in the wireless communications network 1 according to embodiments herein. The UE 10 is configured to perform the number of SDT procedures, each SDT procedure using a respective RA procedure type. The number of SDT procedures may comprise a 2-step SDT procedure and a 4-step SDT procedure based on the RA procedure type.

The UE 10 may comprise processing circuitry 901 , e.g., one or more processors, configured to perform the methods herein.

The UE 10 may comprise a receiving unit 902., e.g., a receiver or transceiver. The UE 10, the processing circuitry 901 and/or the receiving unit 902 may be configured to receive configuration data from the radio network node 12 for handling UL transmissions such as SDT or dedicated transmission over based on one or more rules. The UE may be configured with preconfigured number of SDT procedures. Thus, the UE 10 may be configured by the radio network node 12 or be preconfigured with the number of SDT procedures, e.g., a 2-step SDT procedure, i.e. a 2-step RA for SDT, and 4-step SDT procedure, i.e. 4-step RA for SDT, each being associated with a respective RA procedure type. The 2-step SDT procedure meaning using a 2-step RA procedure for SDT and 4-step SDT procedure meaning using a 4-step RA procedure for SDT. The UE 10 may be configured with parameters, thresholds and the like to determine when to use which SDT procedure. E.g., thresholds for UL message size, signal strength or quality, and/or parameters for configuration, e.g., a table for determining a threshold or parameters to derive such.

The UE 10 may comprise a selecting unit 903. The UE 10, the processing circuitry 901 and/or the selecting unit 903 may be configured to select the one SDT procedure to use based on the threshold for size of an UL message. The UE 10, the processing circuitry 901 and/or the selecting unit 903 may be configured to select the one SDT procedure out of the number of SDT procedures further based on the signal strength or quality. Thus, the UE 10, the processing circuitry 901 and/or the selecting unit 903 may be configured to select the SDT procedure to use based on the size of the UL message and/or the signal strength or quality such as RSRP and/or RSRQ. The UE 10, the processing circuitry 901 and/or the selecting unit 903 may thus be configured to select SDT procedure based on the threshold of the UL message size and/or the threshold of the RSRP. The threshold may be defined by a function of data payload to be transmitted from the UE 10.

The UE 10 may comprise a transmitting unit 904, e.g., a transmitter or a transceiver. The UE 10, the processing circuitry 901 and/or the transmitting unit 904 is configured to perform the SDT according to one SDT procedure out of the number of SDT procedures, selected based on the size of the UL message. Thus, the UE 10, the processing circuitry 901 and/or the transmitting unit 904 is configured to perform the SDT according to the selected SDT procedure. The UE 10 may comprise a memory 905. The memory 905 comprises one or more units to be used to store data on, such as data packets, thresholds, signal strengths/qualities, measurements, RA procedures, events and applications to perform the methods disclosed herein when being executed, and similar. Furthermore, the UE 10 may comprise a communication interface 908 such as comprising a transmitter, a receiver, a transceiver and/or one or more antennas.

The methods according to the embodiments described herein for the UE 10 are respectively implemented by means of, e.g., a computer program product 906 or a computer program, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE 10. The computer program product 906 may be stored on a computer-readable storage medium 907, e.g., a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium 907, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE 10. In some embodiments, the computer-readable storage medium may be a transitory or a non-transitory computer- readable storage medium. Thus, embodiments herein may disclose a UE 10 for handling communication in a wireless communications network, wherein the UE 10 comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said UE 10 is operative to perform any of the methods herein.

Figs. 10a-10b are block diagrams depicting the radio network node 12 in two embodiments for handling communication in the wireless communications network 1 according to embodiments herein.

The radio network node 12 may comprise processing circuitry 1001 , e.g., one or more processors, configured to perform the methods herein.

The radio network node 12 may comprise a configuring unit 1002, e.g., a transmitter or a transceiver. The radio network node 12, the processing circuitry 1001 and/or the configuring unit 1002 is configured to configure the UE 10 to perform SDT procedures, wherein each SDT procedure is using a respective RA procedure type, and wherein a SDT procedure to use is selected based on the size of the UL message. The SDT procedure used by the UE 10 may further be selected based on the signal strength or quality. The radio network node 12, the processing circuitry 1001 and/or the configuring unit 1002 may be configured to configure the UE with a parameter and/or threshold for UL message size, signal strength or quality, and/or parameter for configuration to determine when to use which SDT procedure. The radio network node 12, the processing circuitry 1001 and/or the configuring unit 1002 may be configured to configure the UE 10 with the number of SDT procedures, e.g., a 2-step SDT procedure and 4-step SDT procedure, each being associated with a respective RA procedure type. The radio network node 12, the processing circuitry 1001 and/or the configuring unit 1002 may be configured to configure the UE 10 with parameters, thresholds and/or the like to determine when to use which SDT procedure. E.g., thresholds for UL message size, signal strength or quality, and/or parameters for configuration, e.g., a table for determining a threshold or parameters to derive such. The radio network node 12 may comprise a receiving unit 1003, e.g., a receiver or a transceiver. The radio network node 12, the processing circuitry 1001 and/or the receiving unit 1003 may be configured to receive data using one SDT procedure selected by the UE 10 based on the size of the UL message. Thus, the radio network node 12, the processing circuitry 1001 and/or the receiving unit 1003 may be configured to receive an SDT using an SDT procedure selected by the UE 10 based on size of UL message and/or signal strength or quality.

The radio network node 12 may comprise a memory 1005. The memory 1005 comprises one or more units to be used to store data on, such as data packets, RA configurations, allocated resources, thresholds, events and applications to perform the methods disclosed herein when being executed, and similar. Furthermore, the radio network node 12 may comprise a communication interface 1008 such as comprising a transmitter, a receiver, a transceiver and/or one or more antennas.

The methods according to the embodiments described herein for the radio network node 12 are respectively implemented by means of, e.g., a computer program product 1006 or a computer program, comprising instructions, i.e. , software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the radio network node 12. The computer program product 1006 may be stored on a computer-readable storage medium 1007, e.g., a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium 1007, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the radio network node 12. In some embodiments, the computer-readable storage medium may be a transitory or a non-transitory computer-readable storage medium. Thus, embodiments herein may disclose a radio network node 12 for handling communication in a wireless communications network, wherein the radio network node 12 comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said radio network node 12 is operative to perform any of the methods herein.

In some embodiments a more general term “radio network node” is used and it can correspond to any type of radio-network node or any network node, which communicates with a wireless device and/or with another network node. Examples of network nodes are NodeB, MeNB, SeNB, a network node belonging to Master cell group (MCG) or Secondary cell group (SCG), base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB, gNodeB, network controller, radio-network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission points, transmission nodes, Remote radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), etc.

In some embodiments the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and/or with another wireless device in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, proximity capable UE (aka ProSe UE), machine type UE or UE capable of machine to machine (M2M) communication, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles etc.

Embodiments are applicable to any RAT or multi-RAT systems, where the wireless device receives and/or transmit signals (e.g. data) e.g. New Radio (NR), Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations.

As will be readily understood by those familiar with communications design, that functions means or circuits may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware. In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a wireless device or network node, for example.

Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term “processor” or “controller” as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware and/or program or application data. Other hardware, conventional and/or custom, may also be included. Designers of communications devices will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices. Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

With reference to Fig 11 , in accordance with an embodiment, a communication system includes a telecommunication network 3210, such as a 3GPP-type cellular network, which comprises an access network 3211, such as a radio access network, and a core network 3214. The access network 3211 comprises a plurality of base stations 3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points being examples of the radio network node 12 herein, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c is connectable to the core network 3214 over a wired or wireless connection 3215. A first user equipment (UE) 3291, being an example of the UE 10, located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE 3292 in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a. While a plurality of UEs 3291 , 3292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 3212.

The telecommunication network 3210 is itself connected to a host computer 3230, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 3230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 3221, 3222 between the telecommunication network 3210 and the host computer 3230 may extend directly from the core network 3214 to the host computer 3230 or may go via an optional intermediate network 3220. The intermediate network 3220 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 3220, if any, may be a backbone network or the Internet; in particular, the intermediate network 3220 may comprise two or more sub-networks (not shown).

The communication system of Figure 11 as a whole enables connectivity between one of the connected UEs 3291, 3292 and the host computer 3230. The connectivity may be described as an over-the-top (OTT) connection 3250. The host computer 3230 and the connected UEs 3291 , 3292 are configured to communicate data and/or signaling via the OTT connection 3250, using the access network 3211 , the core network 3214, any intermediate network 3220 and possible further infrastructure (not shown) as intermediaries. The OTT connection 3250 may be transparent in the sense that the participating communication devices through which the OTT connection 3250 passes are unaware of routing of uplink and downlink communications. For example, a base station 3212 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 3230 to be forwarded (e.g., handed over) to a connected UE 3291. Similarly, the base station 3212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 3291 towards the host computer 3230.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Fig. 12. In a communication system 3300, a host computer 3310 comprises hardware 3315 including a communication interface 3316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 3300. The host computer 3310 further comprises processing circuitry 3318, which may have storage and/or processing capabilities. In particular, the processing circuitry 3318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 3310 further comprises software 3311, which is stored in or accessible by the host computer 3310 and executable by the processing circuitry 3318. The software 3311 includes a host application 3312. The host application 3312 may be operable to provide a service to a remote user, such as a UE 3330 connecting via an OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the remote user, the host application 3312 may provide user data which is transmitted using the OTT connection 3350.

The communication system 3300 further includes a base station 3320 provided in a telecommunication system and comprising hardware 3325 enabling it to communicate with the host computer 3310 and with the UE 3330. The hardware 3325 may include a communication interface 3326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 3300, as well as a radio interface 3327 for setting up and maintaining at least a wireless connection 3370 with a UE 3330 located in a coverage area (not shown in Fig.12) served by the base station 3320. The communication interface 3326 may be configured to facilitate a connection 3360 to the host computer 3310. The connection 3360 may be direct or it may pass through a core network (not shown in Fig.12) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 3325 of the base station 3320 further includes processing circuitry 3328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 3320 further has software 3321 stored internally or accessible via an external connection.

The communication system 3300 further includes the UE 3330 already referred to. Its hardware 3335 may include a radio interface 3337 configured to set up and maintain a wireless connection 3370 with a base station serving a coverage area in which the UE 3330 is currently located. The hardware 3335 of the UE 3330 further includes processing circuitry 3338, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 3330 further comprises software 3331 , which is stored in or accessible by the UE 3330 and executable by the processing circuitry 3338. The software 3331 includes a client application 3332. The client application 3332 may be operable to provide a service to a human or non-human user via the UE 3330, with the support of the host computer 3310. In the host computer 3310, an executing host application 3312 may communicate with the executing client application 3332 via the OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the user, the client application 3332 may receive request data from the host application 3312 and provide user data in response to the request data. The OTT connection 3350 may transfer both the request data and the user data. The client application 3332 may interact with the user to generate the user data that it provides.

It is noted that the host computer 3310, base station 3320 and UE 3330 illustrated in Fig. 12 may be identical to the host computer 3230, one of the base stations 3212a, 3212b, 3212c and one of the UEs 3291 , 3292 of Fig. 11 , respectively. This is to say, the inner workings of these entities may be as shown in Fig. 12 and independently, the surrounding network topology may be that of Fig. 11.

In Fig. 12, the OTT connection 3350 has been drawn abstractly to illustrate the communication between the host computer 3310 and the user equipment 3330 via the base station 3320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 3330 or from the service provider operating the host computer 3310, or both. While the OTT connection 3350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 3370 between the UE 3330 and the base station 3320 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 3330 using the OTT connection 3350, in which the wireless connection 3370 forms the last segment. More precisely, the teachings of these embodiments may improve the performance since radio resources may be handled more efficiently and thereby provide benefits such as reduced user waiting time, and better responsiveness.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 3350 between the host computer 3310 and UE 3330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 3350 may be implemented in the software 3311 of the host computer 3310 or in the software 3331 of the UE 3330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 3350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 3311, 3331 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 3350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 3320, and it may be unknown or imperceptible to the base station 3320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer’s 3310 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 3311, 3331 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 3350 while it monitors propagation times, errors etc.

Fig. 13 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 11 and 12. For simplicity of the present disclosure, only drawing references to Figure 13 will be included in this section. In a first step 3410 of the method, the host computer provides user data. In an optional substep 3411 of the first step 3410, the host computer provides the user data by executing a host application. In a second step 3420, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 3430, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 3440, the UE executes a client application associated with the host application executed by the host computer.

Fig. 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 11 and 12. For simplicity of the present disclosure, only drawing references to Figure 14 will be included in this section. In a first step 3510 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 3520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 3530, the UE receives the user data carried in the transmission. Fig. 15 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 11 and 12. For simplicity of the present disclosure, only drawing references to Figure 15 will be included in this section. In an optional first step 3610 of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second step 3620, the UE provides user data. In an optional substep 3621 of the second step 3620, the UE provides the user data by executing a client application. In a further optional substep 3611 of the first step 3610, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third substep 3630, transmission of the user data to the host computer. In a fourth step 3640 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

Fig. 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 11 and 12. For simplicity of the present disclosure, only drawing references to Figure 16 will be included in this section. In an optional first step 3710 of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second step 3720, the base station initiates transmission of the received user data to the host computer. In a third step 3730, the host computer receives the user data carried in the transmission initiated by the base station.

It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

Claims

28 CLAIMS

1. A method performed by a user equipment, UE, (10) for handling communication in a wireless communication network, wherein the UE (10) is configured to perform a number of small data transmission, SDT, procedures, each SDT procedure using a respective random access, RA, procedure type, the method comprising performing (503) a SDT according to one SDT procedure out of the number of SDT procedures, selected based on a size of an uplink, UL, message.

2. The method according to claim 1 , wherein the number of SDT procedures comprise a 2-step SDT procedure and a 4-step SDT procedure based on the RA procedure type.

3. The method according to any of the claims 1-2, further comprising selecting (502) the one SDT procedure to use based on a threshold for size of an UL message.

4. The method according to claim 3, wherein the threshold is defined by a function of data payload to be transmitted from the UE (10).

5. The method according to any of the claims 3-4, wherein selecting the one SDT procedure out of the number of SDT procedures is further based on a signal strength or quality.

6. The method according to any of the claims 1-5, wherein the UE (10) is configured with preconfigured number of SDT procedures.

7. A method performed by a radio network node (12) for handling communication in a wireless communications network, the method comprising configuring (601) a user equipment, UE, (10) to perform small data transmission, SDT, procedures, wherein each SDT procedure is using a respective random access procedure type, and wherein a SDT procedure to use is selected based on a size of an uplink, UL, message.

8. . The method according to claim 7, wherein the SDT procedure used by the UE (10) is further selected based on a signal strength or quality.

9. The method according to any of the claims 7-8, wherein the radio network node (12) further configures the UE (10) with a parameter and/or threshold for UL message size, signal strength or quality, and/or parameter for configuration to determine when to use which SDT procedure.

10. The method according to any of the claims 7-9, further comprising receiving (602) data using one SDT procedure selected by the UE (10) based on the size of the UL message.

11. A user equipment, UE, (10) for handling communication in a wireless communication network, wherein the UE (10) is configured to perform a number of small data transmission, SDT, procedures, each SDT procedure using a respective random access, RA, procedure type, wherein the UE (10) is configured to perform an SDT according to one SDT procedure out of the number of SDT procedures, selected based on a size of an uplink, UL, message.

12. The UE (10) according to claim 11 , wherein the number of SDT procedures comprise a 2-step SDT procedure and a 4-step SDT procedure based on the RA procedure type.

13. The UE (10) according to any of the claims 11-12, wherein the UE (10) is further configured to select the one SDT procedure to use based on a threshold for size of an UL message.

14. The UE (10) according to claim 13, wherein the threshold is defined by a function of data payload to be transmitted from the UE (10).

15. The UE (10) according to any of the claims 13-14, wherein the UE (10) is configured to select the one SDT procedure out of the number of SDT procedures further based on a signal strength or quality.

16. The UE (10) according to any of the claims 11-15, wherein the UE (10) is configured with preconfigured number of SDT procedures.

17. A radio network node (12) for handling communication in a wireless communications network, wherein the radio network node (12) is configured to configure a user equipment, UE, (10) to perform small data transmission, SDT, procedures, wherein each SDT procedure is using a respective random access, RA, procedure type, and wherein a SDT procedure to use is selected based on a size of an uplink, UL, message.

18. The radio network node (12) according to claim 17, wherein the SDT procedure used by the UE (10) is further selected based on a signal strength or quality.

19. The radio network node (12) according to any of the claims 17-18, wherein the radio network node (12) is configured to configure the UE (10) with a parameter and/or threshold for UL message size, signal strength or quality, and/or parameter for configuration to determine when to use which SDT procedure.

20. The radio network node (12) according to any of the claims 17-19, wherein the radio network node (12) is further configured to receive data using one SDT procedure selected by the UE (10) based on the size of the UL message

21. A computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-10, as performed by the UE (10) or the radio network node (12), respectively.

22. A computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-10, as performed by the UE (10) or the radio network node (12), respectively.