Transmitting node, receiving node and methods performed thereby, for handling a radio link control control protocol data unit

Abstract

A computer-implemented method method, performed by a transmitting node (111) operating in a wireless communications network (100). The transmitting node (111) sends (207), to a receiving node (112) operating in the wireless communication network (100), an RLC Control PDU comprising one or more of: a) a PDCP Control PDU and first information indicating that the one or more data units have been discarded by a PDCP entity (122) of the transmitting node (111) and b) second information indicating that one or more data units have been discarded by an RLC entity (121) of the transmitting node (111).

Description

[0001] TRANSMITTING NODE, RECEIVING NODE AND METHODS PERFORMED THEREBY, FOR HANDLING A RADIO LINK CONTROL CONTROL PROTOCOL DATA UNIT

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to a transmitting node and methods performed thereby for handling a Radio Link Control (RLC) Control Protocol Data Unit (PDU). The present disclosure also generally relates to a receiving node and methods performed thereby, for handling the RLC PDU.

[0004] BACKGROUND

[0005] In a communications system such as a wireless communications network, a communication may take place between a transmitting node and a receiving node. Any of the transmitting node and the receiving node may be, for example, a wireless device. Wireless devices within a wireless communications network may be e.g., User Equipments (UEs), stations (ST As), mobile terminals, wireless terminals, terminals, and / or Mobile Stations (MS). Wireless devices are enabled to communicate wirelessly in a cellular communications network or wireless communication network, sometimes also referred to as a cellular radio system, cellular system, or cellular network. The communication may be performed e.g., between two wireless devices, between a wireless device and a regular telephone and / or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the wireless communications network. Wireless devices may further be referred to as mobile telephones, cellular telephones, laptops, or tablets with wireless capability, just to mention some further examples. The wireless devices in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and / or data, via the RAN, with another entity, such as another terminal or a server.

[0006] Any of the transmitting node and the receiving node may be, in other examples, a network node. The wireless communications network covers a geographical area which may be divided into cell areas, each cell area being served by a network node, which may be an access node such as a radio network node, radio node or a base station (BS), e.g., a Radio Base Station (RBS), which sometimes may be referred to as e.g., gNB, evolved Node B (“eNB”), “eNodeB”, “NodeB”, “B node”, Transmission Point (TP), or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations (BSs) may be of different classes such as e.g., Wide Area Base Stations, Medium Range Base Stations, Local Area Base Stations, Home Base Stations, pico base stations, etc..., based on transmission power and thereby also cell size. A cell may be understood to be the geographical area where radio coverage is provided by the base station or radio node at a base station site, or radio node site, respectively. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The base stations communicate over the air interface operating on radio frequencies with the terminals within range of the base stations. In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks. In the context of this disclosure, the expression Downlink (DL) may be used for the transmission path from the base station to the wireless device. The expression Uplink (UL) may be used for the transmission path in the opposite direction i.e., from the wireless device to the base station.

[0007] The standardization organization 3GPP is currently in the process of specifying a New Radio Interface called NR or 5G-UTRA, as well as a Fifth Generation (5G) Packet Core Network (CN), which may be referred to as Next Generation (NG) Core Network, abbreviated as NG-CN, NGC, 5G CN or 5G Core (5GC). NG may be understood to refer to the interface / reference point between the Radio Access Network (RAN) and the CN in 5G / NR. In a 5G System (5GS), a radio base station in NR may be referred to as a gNB or 5G Node B. An NR User Equipment (UE) may be referred to as an nUE.

[0008] Transmitting nodes and receiving nodes may process information, e.g., data, before transmission or after reception with the Packet Data Convergence (PDCP) and Radio Link Control (RLC) protocols.

[0009] Both PDCP and RLC protocols may be understood to have mechanisms to monitor the Protocol Data Units (PDUs) which may be transmitted, received, or pending for reception.

[0010] The PDCP protocol may manage and process data packets before they may be sent over the air. Particularly, the PDCP protocol may help in transferring user data and control information. The PDCP protocol may also perform header compression tasks, reducing the size of data headers to save bandwidth, and security tasks, providing encryption and integrity protection to keep data secure.

[0011] The RLC protocol may be understood to perform tasks such as data segmentation and reassembly. In a transmitting node, the RLC protocol may split large data packets into smaller ones for transmission, while in a receiving node, the RLC protocol may reassemble the split packets. The RLC protocol may also perform error correction tasks, detecting and correcting errors in the data to ensure reliable communication. The RLC protocol may also perform flow control tasks, managing the rate of data transmission to prevent congestion.

[0012] Each protocol of the PDCP protocol and the RLC protocol, may be understood to have a transmitting window on the transmitter side and a receiving window on the receiver side. In a simplified overview, when the PDCP may detect a gap in the receiving window, that is, when at least one or more PDCP Service Data Unit (SDU) may not have been received in order at the receiver side, the PDCP receiver may start a timer, which may be referred to as a T-reordering timer. This may happen when, for example, a PDCP SDU with Sequence Number (SN) equal to X and a second PDCP SDU with SN equal X+2 may arrive to the PDCP receiver. In this example, the PDCP SDU with SN equal to X+1 may be understood to be missing. It may be that this SDU may be under Hybrid Automatic Repeat Request (HARQ) or RLC retransmissions, or it may just be lost. Then, when the receiver may detect the reception of PDCP SDU SN equal to X+2 when it may have been expecting SN equal to X+1 , the PDCP may start the aforementioned timer. When this timer expires, the PDCP receiver may move the receiving window to the next expected PDCP SDU which may not have been delivered to upper layers.

[0013] The receiving PDCP entity may be further configured with “in-order” or “in-sequence” delivery of PDCP Service Data Unit (SDU) packets to higher layers, or “out-of-sequence” or “out-of-order” delivery. The first configuration, in-sequence delivery, may be understood to imply that the PDCP entity may only deliver PDCP SDUs to higher layers in SN order, without gaps. The second, however, “out-of-sequence” may be understood to mean that the receiver PDCP entity may deliver the PDCP SDUs to higher layers as soon as they arrive to the PDCP entity, regardless of whether there may be previous missing PDCP PDUs. In the example above, if “in-sequence” delivery is configured in the receiving PDCP entity, the PDCP entity may not deliver PDCP SDU with SN equal to X+2 until the PDCP SDU with SN equal to X+1 may be received, or the T-reordering timer may expire. On the other hand, if “out-of-sequence” delivery is configured, the PDCP entity may deliver PDCP SDU with SN equal to X+2 when it may be received, regardless of whether PDCP SDU with SN equal to X+1 may be received or not.

[0014] For the first case, “in-sequence” delivery, it may be understood that PDCP PDUs which may have been received but may not be delivered to high layers awaiting for previous PDCP PDUs to arrive or awaiting to the timer to expire, may be queued for a while and experience a delay until they may be delivered to higher layers.

[0015] The RLC window operation may be understood to be similar to that of PDCP, but there may be a few noticeable differences. One of the main differences may be understood to be that successfully received RLC SDUs may be passed forward to the PDCP entity regardless of whether there may be previous RLC SDUs missing or not. For RLC Unacknowledged Mode (UM), the purpose of the receiving window may be understood to be to reassemble RLC SDUs which may have been segmented. Only segmented RLC SDUs may include a SN in their RLC header; others may be understood to not carry any SN. For RLC Acknowledge Mode (AM), however, all RLC SDUs may contain an SN. RLC AM may be understood to be characterized by having the possibility to perform RLC retransmissions and, new retransmissions may further segment previously transmitted data. The RLC receiver entity may transmit RLC STATUS Reports to the RLC transmitter entity which may indicate the successfully and unsuccessfully received RLC SDUs. The transmitter may then retransmit those RLC SDUs which were not successfully received. The RLC may typically update the parameters controlling the RLC receiving window when it may receive an RLC PDU or a complete RLC SDU. When the RLC transmitter may have retransmitted an RLC SDU for a number of times, it may trigger a radio link failure which may cause a cell reselection and a reset of the RLC and Medium Access Control (MAC) layers. Particularly, the RLC may indicate to upper layers that maximum retransmission has been reached. Upper layers, e.g., RRC, may consider such indication as a “detection of a radio link failure” causing the release of the connection and a subsequent cell reselection by the UE to reconnect to the network.

[0016] During Release 19, 3GPP is discussing mechanisms to update the PDCP and RLC transmitting and receiving windows when the transmitter may indicate this to the receiver side. 3GPP may likely specify one mechanism for PDCP and a second mechanism for RLC, both of them independent from each other.

[0017] Existing methods to communicate PDUs between transmitters and receivers in a wireless communications network may result in delays, signalling overhead, wasted resources and / or poor user experience.

[0018] SUMMARY

[0019] As part of the development of embodiments herein, one or more challenges with the existing technology will first be identified and discussed.

[0020] When a PDCP SDU is discarded, for example due to Active Queue Management (AQM) mechanisms, the PDCP entity may be understood to create an SN gap. For example, if the PDCP transmitter entity decides to discard PDCP SN equal to X, then the PDCP receiver entity may receive PDCP PDU with SN equal to X-1 and X+1 , but not equal to X, as it was discarded. As explained above, if “in-sequence” delivery was configured, the PDCP receiver entity may wait unnecessarily as long as the T-reordering timer may be running. This results in an increased latency to deliver data to higher layers.

[0021] Another scenario may be based on services with bounded latency. When an application PDU is queued in the RAN for transmission, this PDU may need to be received by the receiver within a specified latency. If RAN cannot deliver this PDU within the bounded latency, RAN may decide to discard this application PDU. In PDCP, the same problem as described above arises. When the complete or part of the application PDU has started its transmission in the RLC entity and RLC AM is used, the RLC entity cannot discard the application PDU and may therefore need to transmit it. However, given that the bounded latency has been exceeded, it is a waste of resources to transmit such application PDU.

[0022] Another scenario may be when a user may find itself in a cell with no neighboring cells and in a poor radio condition. This may cause multiple RLC retransmissions which may ultimately cause a radio link failure. Yet, the UE may be understood to not be able to camp in any new cell. This may be understood to cause more signalling overhead in the network and a high latency.

[0023] 5G Release 19 is trying to solve this issue adding independent mechanisms in each of the layers to update the receiving window variables; however, this is ineffective as each of the messages may also be transmitted independently from each other. If these messages are transmitted separately, there may be a risk of having state variable mismatches between the transmitter and receiver when these two messages arrive at different points in time to the receiver, or even one of them gets lost. From a resource point of view, transmitting two messages may be understood to result in more power consumption for the NW and UE.

[0024] Certain aspects of the present disclosure and their embodiments address one or more of the challenges identified with the existing methods and provide solutions to these challenges or other challenges.

[0025] According to a first aspect of embodiments herein, the object is achieved by a method, performed by a transmitting node. The transmitting node operates in the wireless communications network. The transmitting node sends, to a receiving node operating in the wireless communication network, an RLC Control PDU. The RLC Control PDU comprises a) one or more of a PDCP Control PDU and first information. The one or more of the PDCP Control PDU and the first information indicates that one or more data units have been discarded by a PDCP entity of the transmitting node. The RLC Control PDU also comprises b) second information indicating that the one or more data units have been discarded by the RLC entity of the transmitting node.

[0026] According to a second aspect of embodiments herein, the object is achieved by a method, performed by a the receiving node. The receiving node operates in the wireless communications network. The receiving node receives, directly or indirectly, from the transmitting node operating in the wireless communication network, the RLC Control PDU. The RLC Control PDU comprises a) the one or more of the PDCP Control PDU and the first information indicating that the one or more data units have been discarded by the PDCP entity of the transmitting node and are to be processed as having been positively received by a PDCP entity of the receiving node. The RLC Control PDU also comprises b) the second information indicating that one or more data units have been discarded by the RLC entity of the transmitting node and are to be processed as having been positively received by an RLC entity of the receiving node. According to a third aspect of embodiments herein, the object is achieved by the transmitting node, configured to perform the method. The transmitting node is configured to operate in the wireless communications network. The transmitting node is configured to send, to the receiving node configured to operate in the wireless communication network, the RLC Control PDU. The RLC Control PDU is configured to comprise: a) the one or more of the PDCP Control PDU and the first information configured to indicate that the one or more data units have been discarded by the PDCP entity of the transmitting node, and b) the second information configured to indicate that the one or more data units have been discarded by the RLC entity of the transmitting node.

[0027] According to a fourth aspect of embodiments herein, the object is achieved by the receiving node, configured to perform the method. The receiving node is configured to operate in the wireless communications network. The receiving node is configured to receive, directly or indirectly, from the transmitting node configured to operate in the wireless communication network, the RLC Control PDU. The RLC Control PDU is configured to comprise: a) the one or more of the PDCP Control PDU and the first information configured to indicate that the one or more data units have been discarded by the PDCP entity of the transmitting node and are to be processed as having been positively received by the PDCP entity of the receiving node, and b) the second information configured to indicate that one or more data units have been discarded by the RLC entity of the transmitting node and are to be processed as having been positively received by the RLC entity of the receiving node.

[0028] By sending the RLC Control PDU comprising the one or more of a PDCP Control PDU and the first information indicating that one or more data units have been discarded by the PDCP entity of the transmitting node and the second information indicating that the one or more data units have been discarded by the RLC entity of the transmitting node, the transmitting node may enable to reduce overhead signalling. If these messages are transmitted separately, each of the messages may contain the respective headers in lower layers. For example, a PDCP PDU may contain, RLC headers + MAC headers.

[0029] Then, if there are two independent messages, the PDCP control message may be understood to have, e.g., 1 PDCP header + 1 RLC header + 1 MAC header. The RLC control may be understood to have, e.g., 1 RLC header + 1 MAC header. Total: 1 PDCP header, 2 RLC headers, 2 MAC headers. Combined there may be, e.g., 1 PDCP header + 1 RLC header + 1 MAC header.

[0030] The transmitting node may also enable to reduce latency. This may be achieved by ensuring that there may only be one RLC PDU containing both messages, so they may be transmitted at the same time by the MAC, which may be in one time instance. While if there are two messages, it may be understood to mean two RLC PDUs, which may be transmitted in two separate time instances. Furthermore, the transmitting node may also enable to avoid having a different state in RLC and PDCP. A different state may be understood to mean that the transmitter may have a different “understanding” of what the state variable values on the receiver side may be. Or that either the PDCP or RLC window on the receiver side may move individually from each other causing the state variables of only one particular layer to change, instead of the window being moved by reception of data, which may cause a natural state variable update in both RLC and PDCP entities. If the state variables are not kept in adequate synchronization, there may be packet losses. The transmitting node may enable to avoid having a different state in RLC and PDCP by transmitting a single message, that is combined message.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

[0033] Figure 1 is a schematic diagram depicting an example of a wireless communications network, according to embodiments herein.

[0034] Figure 2 is a flowchart depicting a method in a transmitting node, according to embodiments herein.

[0035] Figure 3 is a flowchart depicting a method in a receiving node, according to embodiments herein.

[0036] Figure 4 is a schematic diagram depicting of a non-limiting example of an RLC Control PDU, according to embodiments herein.

[0037] Figure 5 is a schematic block diagram illustrating an embodiments of a transmitting node, according to embodiments herein.

[0038] Figure 6 is a schematic block diagram illustrating an embodiments of a receiving node, according to embodiments herein.

[0039] DETAILED DESCRIPTION

[0040] Embodiments herein may be understood to address the problems identified with the existing methods and may be understood to relate to combined PDCP and RLC window control. Embodiments herein may be understood to relate to generating an RLC Control PDU at the RLC transmitter which may include 1) information for the receiver to update the RLC receiving window status variables, and 2) payload, e.g., a PDCP Control PDU, to control the PDCP receiving window status variables.

[0041] Some of the embodiments contemplated will now be described more fully hereinafter with reference to the accompanying drawings, in which examples are shown. In this section, the embodiments herein will be illustrated in more detail by a number of exemplary embodiments. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. It should be noted that the exemplary embodiments herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments.

[0042] Figure 1 depicts two non-limiting examples, in panel a) and panel b), respectively, of a wireless network or wireless communications network 100, sometimes also referred to as a wireless communications system, cellular radio system, or cellular network, in which embodiments herein may be implemented. The wireless communications network 100 may be a 5G system, 5G network, or Next Gen System. In other examples, the wireless communications network 100 may be a newer system, e.g., a Sixth Generation (6G) system, with similar functionality. Yet in other examples, the wireless communications network 100 may in addition, support other technologies such as, for example, Long-Term Evolution (LTE), e.g., LTE for Machines (LTE-M), LTE Frequency Division Duplex (FDD), LTE Time division duplex (TDD), LTE Half-Duplex Frequency Division Duplex (HD-FDD), LTE operating in an unlicensed band, such as LTE Licensed-Assisted Access (LAA), enhanced eLAA (eLAA), further enhanced LAA (feLAA) and / or MulteFire. Yet in other examples, the wireless communications network 100 may further support other technologies such as, for example Wideband Code Division Multiple Access (WCDMA), Universal Terrestrial Radio Access (UTRA) TDD, Global System for Mobile communications (GSM) network, GSM / Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN) network, Ultra-Mobile Broadband (UMB), EDGE network, network comprising any combination of Radio Access Technologies (RATs) such as e.g. Multi-Standard Radio (MSR) base stations, multi-RAT base stations etc., any 3rd Generation Partnership Project (3GPP) cellular network, WiFi networks, Worldwide Interoperability for Microwave Access (WiMax), or any cellular network or system. The wireless communications network 100 may support Machine Type Communication (MTC), enhanced MTC (eMTC), Internet of Things (loT) and / or NarrowBand Internet of Things (NB- loT). Thus, although terminology from 5G / NR and LTE may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the embodiments herein to only the aforementioned system.

[0043] The wireless communications network 100 may comprise a plurality of nodes, whereof a transmitting node 111 and a receiving node 112 are depicted in the non-limiting examples of Figure 1. In some examples, any of the transmitting node 111 and the receiving node 112 may be a radio network node. That is, a transmission point such as a radio base station, for example a gNB, or any other network node with similar features capable of serving a user equipment, such as a wireless device, in the wireless communications network 100. In some examples, any of the transmitting node 111 and the receiving node 112 may be a distributed node, and may partially perform its functions in collaboration with a virtual node 113 in a cloud 115, as depicted in the non-limiting example of panel b) of Figure 1. Any of the transmitting node 111 and the receiving node 112 may be directly connected to one or more core networks, e.g., to one or more network nodes in the one or more core networks.

[0044] In some examples, the wireless communications network 100 may include an access network, such as a radio access network (RAN), and a core network, which may include one or more core network nodes. The access network may include one or more access network nodes, such as any of the transmitting node 111 , the receiving node 112 as radio network nodes, and the virtual node 113, e.g., which may be generally referred to as network nodes, or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node may not necessarily be limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it may be understood that network nodes may include disaggregated implementations or portions thereof. For example, in some embodiments, the wireless communications network 100 may include one or more Open-RAN (ORAN) network nodes. An ORAN network node may be understood to be a node in the wireless communications network 100 that may support an ORAN specification, e.g., a specification published by the O-RAN Alliance, or any similar organization, and may operate alone or together with other nodes to implement one or more functionalities of any node in the wireless communications network 100, including one or more network nodes and / or core network nodes.

[0045] Examples of an ORAN network node may include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller, near-real time or non-real time, hosting software or software plug-ins, such as a near-real time control application, e.g., xApp, or a non-real time control application, e.g., rApp, or any combination thereof, the adjective “open” designating support of an ORAN specification. Any of the transmitting node 111 , the receiving node 112 and the virtual node 113 may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1 , F1 , W1 , E1 , E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment, in which one or more network functions may be virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O- RAN Alliance or comparable technologies.

[0046] The wireless communications network 100 may cover a geographical area, which in some embodiments may be divided into cell areas, wherein each cell area may be served by a radio network node, although, one radio network node may serve one or several cells. In the example of panel b) in Figure 1 , the transmitting node 111 as a radio network node may serve a first cell, which is not depicted to simplify the figure. Any of the transmitting node 111 , the receiving node 112 and the virtual node 113 as network nodes may be of different classes, such as, e.g., macro base station, home base station or pico base station, based on transmission power and thereby also cell size. In some examples, any of the transmitting node 111 , the receiving node 112 and the virtual node 113 may serve receiving nodes with serving beams. Any of the transmitting node 111 , the receiving node 112 and the virtual node 113 may support one or several communication technologies, and its name may depend on the technology and terminology used.

[0047] In some examples, any of the transmitting node 111 and the receiving node 112 may be a wireless device. In some embodiments, the wireless device, as depicted in the non-limiting examples of Figure 1 , the wireless device may be a wireless communication device such as a User Equipment (UE), e.g., 5G UE or nUE, which may also be known as e.g., mobile terminal, wireless terminal and / or mobile station, a mobile telephone, cellular telephone, or laptop with wireless capability, just to mention some further examples. The wireless device may be, for example, portable, pocket-storable, hand-held, computer-comprised, or a vehicle-mounted mobile device, enabled to communicate voice and / or data, via the RAN, with another entity, such as a server, a laptop, a Personal Digital Assistant (PDA), or a tablet, Machine-to-Machine (M2M) device, a sensor, loT device, NB-loT device, device equipped with a wireless interface, such as a printer or a file storage device, modem, or any other radio network unit capable of communicating over a radio link in a communications system. The wireless device may be enabled to communicate wirelessly in the wireless communications network 100. The communication may be performed e.g., via a RAN, and possibly the one or more core networks, which may be comprised within the wireless communications network 100.

[0048] In the non-limiting example of panel a) in Figure 1 , the transmitting node 111 is a wireless device, e.g., a UE, and the receiving node is a network node, e.g., a gNB. In the nonlimiting example of panel b) in Figure 1 , the transmitting node 111 is a network node, e.g., a gNB, and the receiving node is a wireless device, e.g., a UE.

[0049] The transmitting node 111 may comprise an RLC entity 121 , e.g., a first RLC entity 121 , and a PDCP entity 122, e.g., a first PDCP entity 122. The receiving node 112 may comprise an RLC entity 131 , e.g., a second RLC entity 131 , and a PDCP entity 132, e.g., a second PDCP entity 132. In the non-limiting example of panel b) of Figure 1 , the PDCP entity 122 of the transmitting node 111 may be comprised in the virtual node 113 or in the cloud 115. An RLC entity may be understood as a component of a node running RLC protocol. A PDCP entity may be understood as a component of a node running PDCP protocol. The transmitting node 111 may be configured to communicate within the wireless communications network 100 with the receiving node 112 over a first link 141 , e.g., a radio link. Any of the transmitting node 111 and the receiving device 112 as network node may be configured to communicate within the wireless communications network 100 over a second link 142, e.g., a radio link or a wired link.

[0050] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0051] In general, the usage of “first”, “second”, “third”, “fourth” and / or “fifth” herein may be understood to be an arbitrary way to denote different elements or entities, and may be understood to not confer a cumulative or chronological character to the nouns they modify, unless otherwise noted, based on context.

[0052] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments.

[0053] Embodiments of a computer-implemented method, performed by the transmitting node 111 will now be described with reference to the flowchart depicted in Figure 2. The transmitting node 111 operates in the wireless communications network 100. The method may be understood to be for handling an RLC Control PDU.

[0054] In some examples, the wireless communications network 100 may support at least one of: NR, and NB-loT.

[0055] Several embodiments are comprised herein. In some embodiments all the actions may be performed. In some embodiments, one or more actions may be performed. It should be noted that the examples herein may be not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. A non-limiting example of the method performed by the transmitting node 111 is depicted in Figure 2. Some actions may be performed in a different order than that shown in Figure 2. In Figure 2, optional actions are represented with dashed lines.

[0056] Action 201

[0057] During the course of operations of the wireless communications network 100, the PDCP entity 122 of the transmitting node 111 may trigger a discard, e.g., discard itself, of one or more data units, e.g., one or more PDCP SDUs and / or PDUs. This may happen, for example, when the PDCP entity 122 of the transmitting node 111 may detect that, e.g., the PDCP SDU or PDU set may have been too long in the PDCP transmitter buffer, or certain timer associated to the time a PDU Set, e.g., a group of PDUs, or a PDCP SDU may be kept in the buffer may expire.

[0058] In this Action 201 , the transmitting node 111 may determine, by the PDCP entity 122 of the transmitting node 111 , that one or more first variables controlling a window of transmission of the PDCP entity 122 may have to be updated.

[0059] The window of transmission may be understood as a mechanism which may help the transmitter to keep track of the SN used by the transmitter and perform different SN handling operations. The window of transmission may be able to keep track of, for example, and not limiting to, the last / next after last transmitted SN, the last / next SN transmitted in sequence by the transmitter, etc..

[0060] Determining may be understood as calculating, estimating, deriving, deciding or similar.

[0061] The determining in this Action 201 may be based on the PDCP entity 122 of the transmitting node 111 having discarded the one or more data units.

[0062] The one or more first variables may be, e.g., TX_NEXT variable for the transmitter and the corresponding state variables for the receiver. The transmitter may be keeping count, by its own means, of the receiver window or window of reception. In that case, it may also control one or more of the following RX_NEXT, RX_DELIV, RX_REORD.

[0063] The window of reception may be understood as a mechanism which may help the receiver to keep track of the received SN received and perform different SN handling operations. The window of reception may be able to keep track, for example, and not limiting to, of the last / next after last, received SN, the last / next SN received in sequence by the receiver, etc. These variables may be used in the SN handling operations which may trigger positive / negative acknowledgements, discard packets, pass packets to higher layers, etc.

[0064] Updating the one or more first variables may be understood to comprise changing a respective value of one or more of the one or more first variables.

[0065] The updating of the one or more first variables controlling the window of transmission of the PDCP entity 122 may be understood to have as a consequence that the transmitter may keep transmitting new data to the receiving node 112, e.g, a UE.

[0066] Action 202

[0067] In this Action 202, the transmitting node 111 may generate, by the PDCP entity 122 of the transmitting node 111 , one or more of a PDCP Control PDU and first information.

[0068] A PDCP Control PDU may be understood as one type of PDCP PDU. The PDCP Control PDU may be used to convey control information in addition to the PDU header, such as, e.g, an indication which may result in updates to the receiver window, also referred to herein as the window of reception. A PDCP PDU may be as described, for example, in 3GPP TS 38.323, v. 18.3.0.

[0069] The first information from the PDCP entity 122 of the transmitting node 111 may include any information that may be needed by the receiving PDCP entity 132 of the receiving node 112. The first information may be, for example Sequence Number, or COUNT value.

[0070] In some embodiments, instead of generating a PDCP control PDU, the PDCP entity 122 of the transmitting node 111 may generate the first information to the transmitter RLC entity 121 of the transmitting node 111.

[0071] The generating in this Action 202 may be based on a result of the determining in Action 201 being that the one or more first variables controlling the window of transmission of the PDCP entity 122 of the transmitting node 111 may have to be updated.

[0072] The one or more of the PDCP Control PDU and the first information may indicate the one or more data units that may have been discarded.

[0073] By the one or more of the PDCP Control PDU and the first information indicating the one or more data units that may have been discarded, the PDCP entity 132 of the receiving device 112 may then be enabled to consider that the indicated one or more data units may have to be treated as if those one or more data units, e.g., PDCP PDUs, were positively received and thus, the PDCP entity 132 of the receiving device 112 may then trigger the update of the PDCP receiver window one or more first variables accordingly. This may be understood to have as a result that those data units may not be accepted by the receiver node 112 any longer, and that the receiver node 112 may pass data to higher layers if those may have been waiting for the missing data units.

[0074] According to the foregoing, the one or more of the PDCP Control PDU and the first information may indicate the one or more data units that may have been discarded and that may have to be processed as having been positively received by a PDCP entity 132 of the receiving node 112.

[0075] The one or more of the PDCP Control PDU and the first information may indicate the one or more data units by respective indexes of the one or more data units. The respective indexes may be understood to be indexes of the PDCP SDUs and / or PDUs, such as Sequence Number (SN), COUNT, or any other index that may identify each PDCP SDU and / or PDU. That is, a respective PDCP SDU and / or PDU.

[0076] The PDCP entity 122 of the transmitting node 111 may generate the one or more of the PDCP Control PDU and the first information including the respective indexes of the one or more data units which may have been discarded on the transmitter side. An SN or COUNT value corresponding to the PDCP packets may be added in the PDCP Control PDU. This message may alternatively or additionally also include a range of the one or more data units, e.g., PDCP PDUs. For example, first and last values, or first value and a number of consecutive packets.

[0077] The one or more of the PDCP control PDU and the first information may contain multiple options of PDCP data, e.g., not only related to the discarded respective indexes, e.g., SN, but also, for example, long term statistics collected in the PDCP entity 122 of the transmitting node 111. If containing multiple types of PDCP control data, this data may be split up into multiple Control PDUs, or first information, with different priorities. This may be understood to be in order to limit the size of the PDCP control PDU or the first information, so that the most important PDCP control data may be transmitted as fast as possible.

[0078] In some examples of this Action 202, the PDCP entity 122 of the transmitting node 111 may generate the PDCP Control PDU comprising a PDCP data PDU header which may also indicate the PDCP Control PDU includes any PDCP control PDU information. This may later enable that the PDCP entity 132 of the receiving node 112 may extract the PDCP control PDU information from an RLC SDU that the RLC entity 131 of the receiving node 112 may deliver to it.

[0079] Action 203

[0080] When the PDCP entity 122 of the transmitting node 111 may trigger the discard of the one or more data units, e.g., a PDCP SDU and / or PDU, it may need, according to embodiments herein, to inform the RLC entity 121 of the transmitting node 111 about it. This may be performed by the PDCP entity 122 of the transmitting node 111 sending the generated one or more of the PDCP Control PDU and the first information to the RLC entity 121 of the transmitting node 111.

[0081] In this Action 203, the transmitting node 111 may receive, by the RLC entity 121 of the transmitting node 111 , from the PDCP entity 122 of the transmitting node 111 , the one or more of the PDCP Control PDU and the first information indicating the one or more data units that may have been discarded by the PDCP entity 122 of the transmitting node 111. The PDCP entity 122 may be understood to be a transmitter of the one or more data units.

[0082] In some embodiments, the PDCP entity 122 of the transmitting node 111 submitting the PDCP control PDU to the RLC layer, may indicate to the RLC entity 121 of the transmitting node 111 to add the PDCP control payload to the payload of an RLC control PDU.

[0083] In some embodiments as stated earlier, instead of in this Action 203 generating the PDCP control PDU that may later be used as an RLC payload, the PDCP entity 122 of the transmitting node 111 may provide the first information to the transmitter RLC entity 121 of the transmitting node 111.

[0084] Action 204

[0085] Additionally, in some examples, the PDCP entity 122 of the transmitting node 111 may indicate to the RLC entity 121 of the transmitting node 111 whether the one or more of the PDCP Control PDU and the first information may need to be prioritized or not, and / or the priority level, e.g. the place it may need to be put in the RLC queue, e.g. inserted at the head or tail in an RLC queue. For example, if the one or more of the PDCP control PDU and the first information is carrying long term statistics collected in the PDCP entity 122 of the transmitting node 111 , such information may be considered as less important, that is, less urgent, whereas a PDCP control PDU carrying SN gap information may be considered very important, that is, urgent. Thus, the one or more of the PDCP control PDU and the first information carrying PDCP statistic information may be put behind another PDCP control PDU or first information carrying PDCP SN gap information in the RLC queue, e.g., in a less prioritized RLC control PDU.

[0086] In some embodiments, in this Action 204, the transmitting node 111 may obtain, by the RLC entity 121 of the transmitting node 111 , a first indication from the PDCP entity 122 of the transmitting node 111 indicating a priority of the one or more of the PDCP Control PDU and the first information.

[0087] In a distributed system, in the DL, such first indication may be carried in the interface between the Centralized Unit (CU) and Distributed Unit (DU), F1 in 5G for instance. In the UL, the network may configure a wireless device or UE with rules indicating which type of PDCP Control PDUs and / or RLC Control PDUs may have higher or lower priority over other data queued in the buffer and also what split and / or combinations of control data that may need to be followed. For cross layer, the type of data that may be sent on a Control PDU to the RLC entity 121 of the transmitting node 111 may contain the first indication indicating what type of data it may comprise and its priority. In the downlink and in distributed systems where the PDCP entity 122 of the transmitting node 111 may reside in the CU and the RLC entity 121 of the transmitting node 111 may reside in in the DU, signaling between these two entities may need to provide enough information for the RLC entity 121 of the transmitting node 111 to know that a certain PDCP PDU is a control PDU. The PDCP entity 122 of the transmitting node 111 may therefore possibly need to indicate one or more of the following: user data PDCP PDU or PDCP Control PDU, a type of control PDU, and the relevant PDCP PDU indexes, directly or indirectly, so that the RLC entity 121 of the transmitting node 111 may also identify the RLC SDU / PDU indexes associated to the PDCP PDU indexes.

[0088] With this information, the RLC entity 121 of the transmitting node 111 in the DU may be able to identify the type of PDCP PDU and, in case of a PDCP Control PDU, to decide whether to construct an RLC Control PDU attaching the PDCP PDU as the RLC PDU payload, or take another related action.

[0089] Action 205

[0090] In this Action 205, the transmitting node 111 may determine, by the RLC entity 121 of the transmitting node 111 , whether or not the RLC entity 121 may have one or more service data units associated to the one or more data units.

[0091] The determining in this Action 205, by the RLC entity 121 of the transmitting node 111 , of whether or not the RLC entity 121 may have one or more service data units associated to the one or more data units may be based on the indicated respective indexes, e.g., SNs. The RLC entity 121 of the transmitting node 111 may identify the RLC SDUs and their corresponding indexes which may be associated to the indicated respective indexes of the one or more data units, e.g., PDCP PDU indexes, and in this way build a corresponding RLC Control PDU.

[0092] Action 206

[0093] In this Action 206, the transmitting node 111 may generate, by the RLC entity 121 of the transmitting node 111 , an RLC Control PDU.

[0094] An RLC Control PDU may be understood as one type of RLC PDU. RLC control PDUs may, for example, be used by Acknowledged Mode (AM) RLC entity to perform Automatic repeat request (ARQ) procedures.

[0095] The RLC entity 121 of the transmitting node 111 may generate the RLC Control PDU by adding the received one or more of the PDCP Control PDU and the first information as one of payload and third information. That is, in some examples, the generated RLC Control PDU may comprise the received PDCP Control PDU as payload. In other examples, the generated RLC Control PDU may comprise the received PDCP Control PDU, not as payload as such, but after processing by the RLC entity 121 of the transmitting node 111 , as information, referred to herein as “third information”. In other examples, the generated RLC Control PDU may comprise the received first information as payload as such. In yet other examples, the generated RLC Control PDU may comprise the received first information not as payload as such, but as the third information after processing by the RLC entity 121 of the transmitting node 111.

[0096] The generating in this Action 206 may be performed with the proviso the RLC entity 121 may determine, in Action 205, that the RLC entity 121 has one or more service data units associated to the one or more data units.

[0097] In some embodiments, the generating in this Action 206 may comprise adding additional RLC control data to the RLC Control PDU. Such additional RLC control data may be understood to be additional to the second information and may comprise, for example, a priority indication. Such indication may be provided through the F1 interface for DL. The benefit of such an approach may be understood to be that the RLC Control PDU may carry both, PDCP control data and RLC control data, and as such, a MAC layer of the transmitting node 111 may prioritize such RLC Control PDU.

[0098] In some embodiments, the RLC Control PDU may have a format. In some of such embodiments, the format may further comprise one or more of the following options.

[0099] According to a first option, the format may further comprise a first field indicating that the RLC Control PDU is a control PDU. The first field may be, for example, a Data / Control (D / C) field, which may indicate whether the PDU may be a Data (D) or Control (C) PDU.

[0100] According to a second option, the format may further comprise a second field indicating a type of the RLC Control PDU. The type of the RLC Control PDU may be understood to It differentiate what type of content the RLC Control PDU may carry. The second field may be, for example, a Control PDU Type (CPT) field, which may indicate the Control PDU Type codepoint. That is, a field to a look-up table indicating what the payload may be.

[0101] The D / C and CPT may be understood to correspond to the legacy RLC header, where the D / C may indicate whether the PDU may be a Data (D) or Control (C) PDU.

[0102] According to a third option, the format may further comprise a third field indicating a first length of a first payload of the RLC control PDU. The first payload may be understood to be the payload of the RLC Control PDU that may carry RLC information, e.g., the RLC data units to be discarded, e.g. SN of such RLC PDUs.

[0103] The third field may be, for example, an RLC Control Payload length field indicating a size, e.g., in bytes, of the RLC Control PDU payload in case of variable length payload. Alternatively, the size may be indicated by the second field, e.g., the CPT field, or by additional extension bits in the RLC Control payload itself.

[0104] According to a fourth option, the format may further comprise the RLC Control PDU first pay load.

[0105] In some embodiments, the RLC entity 121 may receive the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111 , and the RLC Control PDU may comprise the PDCP Control PDU as a second payload. The second payload may be understood to be the payload of the RLC Control PDU that may carry PDCP information. In some examples, the PDCP Control PDU may be delivered to the RLC entity 121 of the transmitting node 111 , which may add it as the second payload to the RLC Control PDU. In some examples, the PDCP Control payload may include the full PDCP Control PDU including its PDCP header.

[0106] In other examples, the RLC entity 121 may receive the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111 , and the RLC Control PDU may comprise the third information as the second payload. The third information may be understood to be derived by, the RLC entity 121 of the transmitting node 111 , from the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111.

[0107] In some of the examples wherein, instead of generating a PDCP control PDU that may be used as an RLC payload, the PDCP entity 122 of the transmitting node 111 may have provided the first information to the RLC entity 121 of the transmitting node 111 , the RLC entity 121 of the transmitting node 111 may create the RLC control PDU including the first information from the PDCP entity 122 of the transmitting node 111. This may be understood to avoid creating a PDCP control PDU header.

[0108] In some examples wherein the RLC entity 121 may have received the first information from the PDCP entity 122 of the transmitting node 111 , the RLC Control PDU may comprise the first information as the second payload.

[0109] In some embodiments, the format may further comprise one or more of the following options:

[0110] According to a first option, the format may further comprise the second field further indicating whether or not the RLC Control PDU comprises a PDCP Control PDU as payload. In some examples, the CPT field may indicate the type of RLC Control PDU, as well as whether the RLC Control PDU may comprise a PDCP Control PDU as payload.

[0111] In some examples, in order to indicate that the RLC control PDU has first information intended to the receiving PDCP entity 132 of the receiving node 112, the RLC control PDU header may have a bit field to refer the type of PDCP information. For example, one extra bit may be added in the RLC control PDU header and if it is set to 0, no PDCP information may be included so all information in the RLC control PDU may be understood to be for the RLC entity 131 of the receiving node 112. If it is set as 1 , the RLC entity 131 of the receiving node 112 may know there is a PDCP sequence number to be discarded which may be added after RLC control PDU payload.

[0112] According to a second option, the format may further comprise one of: a fourth field indicating a second length of the PDCP control PDU, and a fifth field indicating a type of the PDCP Control PDU. For example, the type of the PDCP Control PDU may be one of: a PDCP status report, an interspersed Robust Header Compression (ROHC) feedback, an Ethernet Header Compression (EHC) feedback, an Uplink Data Compression (UDC) feedback, a PDCP SN gap report.

[0113] The fourth field may be, for example a PDCP control Payload length field. If present, the PDCP control Payload length may indicate the length of the PDCP Control PDU. However, the length field may not be needed as it may be aggregated in other headers e.g., RLC or MAC.

[0114] Instead of indicating the PDCP control payload length, the third field, e.g., the CPT or any new field, may indicate the type of PDCP control PDU, whose size may be predetermined.

[0115] According to a third option, the format may further comprise one or more PDU indexes, e.g.,, the respective indexes of the one or more data units and the .

[0116] In some of the examples wherein the PDCP Control PDU may be delivered to the RLC entity 121 of the transmitting node 111 , which may add it as a second payload to the RLC Control PDU, this RLC control PDU may include the associated RLC SN, as determined in Action 205, if those were included, of the RLC SDUs the RLC entity 121 of the transmitting node 111 may discard.

[0117] Action 207

[0118] In this Action 207, the transmitting node 111 sends, to the receiving node 112 operating in the wireless communication network 100, the RLC Control PDU. The RLC Control PDU comprises a) the one or more of the PDCP Control PDU and the first information. The one or more of the PDCP Control PDU and the first information indicates that the one or more data units have been discarded by the PDCP entity 122 of the transmitting node 111 , and b) the second information indicates that one or more data units have been discarded by the RLC entity 121 of the transmitting node 111 , e.g., the one or more data units associated to those discarded by the PDCP entity 122.

[0119] The sent RLC Control PDU may be the generated RLC Control PDU in Action 206.

[0120] In some embodiments, the sending in this Action 207 of the RLC Control PDU may be based on the indicated priority in Action 204.

[0121] In some embodiments, the sent RLC Control PDU may comprise the additional RLC control data.

[0122] In some embodiments, the RLC Control PDU may lack the PDCP Control PDU as payload. In some of such embodiments, the received PDCP Control PDU may be included as third information, and the RLC Control PDU may further comprise a fourth indication indicating a type of the third information. In some embodiments, the RLC entity 121 of the transmitting node 111 may receive the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111 , and the PDCP Control PDU may be one of a plurality of PDCP Control PDUs sent by the transmitting node 111. In some of such embodiments, each of the PDCP Control PDUs in the plurality may have a respective priority.

[0123] Embodiments of a computer-implemented method, performed by the receiving node 112 will now be described with reference to the flowchart depicted in Figure 3. The receiving node 112 operates in the wireless communications network 100. The method may be understood to be for handling an RLC Control PDU.

[0124] In some examples, the wireless communications network 100 may support at least one of: NR and NB-loT.

[0125] Several embodiments are comprised herein. It should be noted that the examples herein may be not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. A non-limiting example of the method performed by the receiving node 112 is depicted in Figure 3. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the transmitting node 111 , and will thus not be repeated here. For example, in some examples, in the downlink and in distributed systems, the PDCP entity 122 of the transmitting node 111 may reside in a CU and the RLC entity 121 of the transmitting node 111 may reside in a DU.

[0126] Action 301

[0127] In this Action 301 , the receiving node 112 receives, directly or indirectly, from the transmitting node 111 operating in the wireless communication network 100, the RLC Control PDU. The RLC Control PDU comprises the one or more of the PDCP Control PDU and the first information indicating that the one or more data units have been discarded by the PDCP entity 122 of the transmitting node 111 and are to be processed as having been positively received by a PDCP entity 132 of the receiving node 112. The RLC Control PDU also comprises the second information indicating that one or more data units have been discarded by the RLC entity 121 of the transmitting node 111 and are to be processed as having been positively received by the RLC entity 131 of the receiving node 112.

[0128] In some embodiments, the RLC Control PDU may have the format. The format may further comprise one or more of: the first field indicating that the RLC Control PDU is a control PDU, the second field indicating the type of the RLC Control PDU, the third field indicating the first length of the first payload of the RLC control PDU, and the RLC Control PDU first payload.

[0129] In some embodiments, the RLC Control PDU may comprise the PDCP Control PDU as the second payload.

[0130] In some embodiments, the

[0131] In some embodiments, the format may further comprise one or more of: a) the second field further indicating whether or not the RLC Control PDU comprises the PDCP Control PDU as payload, b) the one of: i) the fourth field indicating the second length of the PDCP control PDU, and ii) the fifth field indicating the type of the PDCP Control PDU, and c) the one or more PDU indexes.

[0132] In some embodiments, wherein the RLC Control PDU may lack the PDCP Control PDU as payload, the received PDCP Control PDU may be included as the third information, and the RLC Control PDU may further comprise the fourth indication indicating the type of the third information.

[0133] In some embodiments, the received RLC Control PDU may comprise the additional RLC control data.

[0134] In some embodiments, the receiving in this Action 301 of the RLC Control PDU may be based on the priority.

[0135] In some embodiments, the PDCP Control PDU may be one of a plurality of PDCP Control PDUs sent by the transmitting node 111 , and each of the PDCP Control PDUs in the plurality may have respective priority.

[0136] Action 302

[0137] In this Action 301 , the receiving node 112 may decode, by the RLC entity 131 of the receiving node 112, the received RLC Control PDU.

[0138] Upon the reception of the RLC PDU in RLC receiver, the RLC entity 131 of the receiving node 112 may decode the D / C, CPT, RLC payload and, if one of the header fields e.g., CPT, indicates that there is PDCP Control payload, the RLC entity 131 of the receiving node 112 may, in Action 305, pass the PDCP Control Payload to the PDCP layer, that is, to the PDCP entity 132 of the receiving node 112.

[0139] Action 303

[0140] In this Action 303, the receiving node 112 may extract, by the RLC entity 131 of the receiving node 112, the one or more of the PDCP Control PDU and the first information as payload from the received the RLC Control PDU.

[0141] In this Action 303, when the RLC entity 131 of the receiving node 112 may receive the RLC control PDU, the RLC entity 131 of the receiving node 112 may extract the information intended for the PDCP entity 132 of the receiving node 112 and inform the information. This information may be any of the PDCP Control PDU and the first information, as payload or as the third information.

[0142] The receiving RLC entity 131 of the receiving node 112 may only take the PDCP control PDU part of the RLC Control PDU to serve it to PDCP layer, that is, to PDCP entity 132 of the receiving node 112.

[0143] In some of the examples, as stated earlier, instead of indicating the PDCP control payload length, the third field, e.g., CPT or any new field, may indicate the type of PDCP control PDU whose size may be pre-determined. This may be used by the RLC entity 131 of the receiving node 112 to know what information to extract and send to the PDCP entity 132 of the receiving node 112.

[0144] Action 304

[0145] In this Action 304, the receiving node 112 may perform, by the RLC entity 131 of the receiving node 112, a first action based on the decoded RLC Control PDU.

[0146] In some embodiments, the one or more of the following may apply. According to a first option, the first action may be performed based on one or more PDU indexes comprised in the received RLC Control PDU. According to a second option, the first action may comprise updating one or more second variables controlling a window of reception of the RLC entity 131 of the receiving device 112.

[0147] In some examples, the RLC receiver side may update the corresponding parameters when it may get the RLC Control PDU and may deliver the second payload to the PDCP entity 132 of the receiving node 112 in the next Action 305.

[0148] The RLC layer, however, may check the content of the RLC Control payload and act upon the indexes indicated therein. The receiver side may consider that the indicated indexes may need to be treated as if those RLC PDUs were positively received and thus, one or more second variables controlling a window of reception of the RLC entity 131 of the receiving device 112 may be updated accordingly.

[0149] The one or more second variables may be considered to be as described for the one or more first variables.

[0150] Updating the one or more second variables may be considered to be as described for the one or more first variables.

[0151] The updating of the one or more second variables controlling the window of reception of the RLC entity 131 of the receiving node 112 may be understood to have as a consequence, for example, not accepting those PDUs if received later, and may result in restarting or stopping timers controlling the receiver window e.g., t-assembly. Action 305

[0152] In this Action 305, the receiving node 112 may send, by the RLC entity 131 of the receiving node 112, to the PDCP entity 132 of the receiving node 112, an RLC SDU comprising the extracted one or more of the PDCP Control PDU and the first information as pay load.

[0153] Action 306

[0154] The PDCP entity 132 of the receiving node 112 may extract the PDCP control PDU information from the delivered RLC SDU. For this, PDCP data PDU header may also indicate if it may include any PDCP control PDU information.

[0155] In this Action 306, the receiving node 112 may decode, by the PDCP entity 132 of the receiving node 112, the received one or more of the PDCP Control PDU and the first information.

[0156] Action 307

[0157] In this Action 307, the receiving node 112 may perform, by the PDCP entity 132 of the receiving node 112, a second action based on the decoded PDCP Control PDU. For example, similarly to the RLC layer, the PDCP layer may check the content of the PDCP Control PDU and act upon the indexes indicated therein.

[0158] In some embodiments, the one or more of the following may apply. According to a first option, the second action may be performed based on one or more PDU indexes comprised in the received PDCP Control PDU or the first information. According to a second option, the second action may comprise updating one or more third variables controlling a window of reception of the PDCP entity 132 of the receiving device 112. The PDCP entity 132 of the receiving node 112 may update the receiver window considering the information received in the PDCP Control PDU.

[0159] The PDCP entity 132 of the receiving node 112 may consider that the indicated indexes may need to be treated as if those PDCP PDUs were positively received and thus, the one or more third variables controlling the window of reception of the PDCP entity 132 of the receiving device 112 may be updated accordingly.

[0160] The one or more third variables may be considered to be as described for the one or more first variables.

[0161] Updating the one or more third variables may be considered to be as described for the one or more first variables.

[0162] The updating of the one or more third variables controlling the window of transmission of the PDCP entity 132 of the receiving node 112 may be understood to have as a consequence, e.g., not accepting those PDUs if received later, stop / re-start t-reordering timer, allow continuing the upper part of the window.

[0163] Figure 4 is a schematic diagram showing a non-limiting example format of a PDCP Control PDU 401 aggregated with a RLC Control PDU 402, according to embodiments herein. In the non-limiting example depicted in Figure 4, the format comprises the first field 403 as the D / C indicating whether the PDU may be a Data or Control PDU. The format also comprises the second field 404 as the CPT field indicating the Control PDU Type codepoint that may be a field to a look-up table indicating what the payload is. The CPT field in this example may indicate the type of RLC Control PDU as well as whether the Control PDU may contain a PDCP Control PDU as payload. The D / C and Control PDU Type (CPT) may be understood to correspond to the legacy RLC header where the D / C indicate whether the PDU is a Data or Control PDU. The format also comprises the third field 405 as the RLC Control Payload length indicating the size, e.g., in bytes, of the first payload 406 of the RLC Control PDU in case of variable length payload. Alternatively, the size may be indicated by the CPT field or by additional extension bits in the RLC Control payload itself. The PDCP Control second payload 407 in this example may include the full PDCP Control PDU including its PDCP header. If present, as in the depicted example in Figure 4, the fourth field 408, the PDCP control Payload length, may indicate the length of the PDCP Control PDU 401. However, length field may not be needed as it may be aggregated in other headers e.g., RLC or MAC. The number of bits 409 is schematically indicated at the top of Figure 4.

[0164] Certain embodiments disclosed herein may provide one or more of the following technical advantage(s), which may be summarized as follows. Embodiments herein, may be understood to enable to reduce overhead signalling, reduce latency, and avoid having a different state in RLC and PDCP.

[0165] Figure 5 depicts an example of the arrangement that the transmitting node 111 may comprise to perform the method actions described above in relation to Figure 2, and / or Figure 4. The transmitting node 111 may be understood to be for handling the RLC Control PDU. The transmitting node 111 may be configured to operate in the wireless communications network 100.

[0166] In some examples, the wireless communications network 100 may be configured to support at least one of: NR and NB-loT.

[0167] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the transmitting node 111 and will thus not be repeated here. For example, in some examples, in the downlink and in distributed systems, the PDCP entity 122 of the transmitting node 111 may be configured to reside in a CU and the RLC entity 121 of the transmitting node 111 may be configured to reside in a DU.

[0168] The transmitting node 111 is configured to send, to the receiving node 112 configured to operate in the wireless communication network 100, the RLC Control PDU, configured to comprise: a) the one or more of the PDCP Control PDU and the first information configured to indicate that the one or more data units have been discarded by the PDCP entity 122 of the transmitting node 111 , and b) the second information configured to indicate that the one or more data units have been discarded by the RLC entity 121 of the transmitting node 111.

[0169] In some embodiments, the transmitting node 111 may be further configured the following three configurations.

[0170] In some embodiments, the transmitting node 111 may be further configured to receive, by the RLC entity 121 of the transmitting node 111 , from the PDCP entity 122 of the transmitting node 111 , the one or more of the PDCP Control PDU and the first information configured to indicate the one or more data units that may have been discarded by the PDCP entity 122 of the transmitting node 111. The PDCP entity 122 may be configured to be the transmitter of the one or more data units.

[0171] In some embodiments, the transmitting node 111 may be further configured to determine, by the RLC entity 121 of the transmitting node 111 , whether or not the RLC entity 121 may have one or more service data units associated to the one or more data units.

[0172] In some embodiments, the transmitting node 111 may be further configured to generate, by the RLC entity 121 of the transmitting node 111 , the RLC Control PDU by adding the one or more of the PDCP Control PDU and the first information configured to be received as one of payload and third information. The RLC Control PDU configured to be sent may be configured to be the RLC Control PDU configured to be generated. The generating may be configured to be performed with the proviso the RLC entity 121 may determine that the RLC entity 121 has one or more service data units associated to the one or more data units.

[0173] In some embodiments, the generating may be configured to comprise adding the additional RLC control data to the RLC Control PDU. The RLC Control PDU configured to be sent may be configured to comprise the additional RLC control data.

[0174] In some embodiments, the transmitting node 111 may be further configured with the following three configurations. In some embodiments, the transmitting node 111 may be further configured to determine, by the PDCP entity 122 of the transmitting node 111 , that the one or more first variables configured to control the window of transmission of the PDCP entity 122 may have to be updated.

[0175] In some embodiments, the transmitting node 111 may be further configured to generate, by the PDCP entity 122, the one or more of the PDCP Control PDU and the first information based on the result of the determining being that the one or more first variables configured to control the window of transmission of the PDCP entity 122 of the transmitting node 111 may have to be updated. The PDCP Control PDU may be configured to indicate the one or more data units that may have been discarded, and that may have to be processed as having been positively received by the PDCP entity 132 of the receiving node 112, by the respective indexes of the one or more data units. The determining, by the RLC entity 121 of the transmitting node 111 , of whether or not the RLC entity 121 of the transmitting node 111 may have the one or more service data units associated to the one or more data units may be configured to be based on the respective indexes configured to be indicated.

[0176] In some embodiments, the transmitting node 111 may be further configured to obtain, by the RLC entity 121 of the transmitting node 111 , the first indication from the PDCP entity 122 of the transmitting node 111 configured to indicate the priority of the one or more of the PDCP Control PDU and the first information. The sending of the RLC Control PDU may be configured to be based on the priority configured to be indicated.

[0177] In some embodiments, the RLC Control PDU may be configured to have the format. The format may be further configured to comprise one or more of: the first field configured to indicate that the RLC Control PDU is the control PDU, the second field configured to indicate the type of the RLC Control PDU, the third field configured to indicate the first length of the first payload of the RLC control PDU, and the RLC Control PDU first payload.

[0178] In some embodiments, the RLC entity 121 may be configured to receive the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111 , and the RLC Control PDU may be configured to comprise the PDCP Control PDU as the second payload.

[0179] In some embodiments, the format may be further configured to comprise one or more of: a) the second field being configured to further indicate whether or not the RLC Control PDU comprises a PDCP Control PDU as payload, b) the one of: the fourth field configured to indicate the second length of the PDCP control PDU, and the fifth field configured to indicate the type of the PDCP Control PDU, and c) the one or more PDU indexes.

[0180] In some embodiments, the RLC entity 121 of the transmitting node 111 is configured to receive the PDCP Control PDU from the PDCP entity 122 of the transmitting node 111 , and wherein the PDCP Control PDU is configured to be one of a plurality of PDCP Control PDUs configured to be sent by the transmitting node 111 , and each of the PDCP Control PDUs in the plurality may be configured to have the respective priority.

[0181] In some embodiments, the RLC Control PDU may be configured to lack the PDCP Control PDU as payload, the PDCP Control PDU configured to be received may be configured to be included as third information, and the RLC Control PDU may be further configured to comprise the fourth indication configured to indicate the type of the third information.

[0182] The embodiments herein in the transmitting node 111 may be implemented through one or more processors, such as a processing circuitry 501 in the transmitting node 111 depicted in Figure 5, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the transmitting node 111. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the transmitting node 111.

[0183] The processing circuitry 501 may be configured to, or operable to, perform the method actions according to Figure 2, and / or Figure 4.

[0184] The transmitting node 111 may further comprise a memory 502 comprising one or more memory units. The memory 502 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the transmitting node 111.

[0185] In some embodiments, the transmitting node 111 may receive information from, e.g., the receiving node 112, the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100, through a receiving port 503. In some embodiments, the receiving port 503 may be, for example, connected to one or more antennas in transmitting node 111. Since the receiving port 503 may be in communication with the processing circuitry 501 , the receiving port 503 may then send the received information to the processing circuitry 501 . The receiving port 503 may also be configured to receive other information.

[0186] The processing circuitry 501 in the transmitting node 111 may be further configured to transmit or send information to e.g., the receiving node 112, the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100, through a sending port 504, which may be in communication with the processing circuitry 501 , and the memory 502.

[0187] Those skilled in the art will also appreciate that the processing circuitry 501 described above may comprise a combination of analog and digital modules, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 501 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0188] Also, in some embodiments, the transmitting node 111 may be configured to perform the actions of Figure 2, and / or Figure 4 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 501 .

[0189] The transmitting node 111 may be configured to perform any of the Actions described in relation to Figure 2, and / or Figure 4, e.g., by means of the processing circuitry 501 within the transmitting node 111 , configured to perform any of such actions.

[0190] Thus, the methods according to the embodiments described herein for the transmitting node 111 may be respectively implemented by means of a computer program 505 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 501 , cause the at least one processing circuitry 501 to carry out the actions described herein, as performed by the transmitting node 111. The computer program 505 product may be stored on a computer-readable storage medium 506. The computer- readable storage medium 506, having stored there on the computer program 505, may comprise instructions which, when executed on at least one processing circuitry 501 , cause the at least one processing circuitry 501 to carry out the actions described herein, as performed by the transmitting node 111. In some embodiments, the computer-readable storage medium 506 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 505 product may be stored on a carrier containing the computer program 505 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 506, as described above.

[0191] The transmitting node 111 may comprise a communication interface configured to facilitate communications between the transmitting node 111 and other nodes or devices, e.g., the receiving node 112, the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0192] In other embodiments, the transmitting node 111 may also comprise a radio circuitry 507, which may comprise e.g., the receiving port 503 and the sending port 504. The radio circuitry 507 may be configured to set up and maintain at least a wireless connection with the receiving node 112, the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0193] Hence, embodiments herein also relate to the transmitting node 111 comprising the processing circuitry 501 and the memory 502, said memory 502 containing instructions executable by said processing circuitry 501 , whereby the transmitting node 111 is operative to perform the actions described herein in relation to the transmitting node 111 , e.g., in Figure 2, and / or Figure 4.

[0194] Figure 6 depicts an example of the arrangement that the receiving node 112 may comprise to perform the method actions described above in relation to Figure 3 and / or Figure 4. The receiving node 112 may be understood to be for handling the RLC Control PDU. The receiving node 112 may be configured to operate in the wireless communications network 100.

[0195] In some examples, the wireless communications network 100 may be configured to support at least one of: NR and NB-loT.

[0196] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the receiving node 112 and will thus not be repeated here. For example, in some examples, in the downlink and in distributed systems, the PDCP entity 122 of the transmitting node 111 may be configured to reside in a CU and the RLC entity 121 of the transmitting node 111 may be configured to reside in a DU.

[0197] The receiving node 112 is configured to receive, directly or indirectly, from the transmitting node 111 configured to operate in the wireless communication network 100, the RLC Control PDU configured to comprise: a) the one or more of the PDCP Control PDU and the first information configured to indicate that the one or more data units have been discarded by the PDCP entity 122 of the transmitting node 111 and are to be processed as having been positively received by a PDCP entity 132 of the receiving node 112, and b) the second information configured to indicate that one or more data units have been discarded by the RLC entity 121 of the transmitting node 111 and are to be processed as having been positively received by the RLC entity 131 of the receiving node 112.

[0198] In some embodiments, the RLC Control PDU configured to be received may be configured to comprise the additional RLC control data.

[0199] In some embodiments, the receiving of the RLC Control PDU may be configured to be based on the priority.

[0200] In some embodiments, the RLC Control PDU may be configured to have the format and the format may be configured to further comprise one or more of: a) the first field configured to indicate that the RLC Control PDU is a control PDU, b) the second field configured to indicate the type of the RLC Control PDU, c) the third field configured to indicate the first length of the first payload of the RLC control PDU, and d) the RLC Control PDU first payload.

[0201] In some embodiments, the RLC Control PDU may be configured to comprise the PDCP Control PDU as the second payload.

[0202] In some embodiments, the PDCP Control PDU may be configured to be one of the plurality of PDCP Control PDUs configured to be sent by the transmitting node 111 , and each of the PDCP Control PDUs in the plurality may be configured to have the respective priority.

[0203] In some embodiments, the format may be further configured to comprise one or more of: i) the second field further configured to indicate whether or not the RLC Control PDU may comprise a PDCP Control PDU as payload, ii) one of: the fourth field configured to indicate the second length of the PDCP control PDU, and the fifth field configured to indicate the type of the PDCP Control PDU, and iii) the one or more PDU indexes.

[0204] In some embodiments, the receiving node 112 may be further configured with one or more of the following two configurations.

[0205] In some embodiments, the receiving node 112 may be further configured to decode, by the RLC entity 131 of the receiving node 112, the RLC Control PDU configured to be received.

[0206] In some embodiments, the receiving node 112 may be further configured to perform, by the RLC entity 131 of the receiving node 112, the first action based on the RLC Control PDU configured to be decoded.

[0207] In some embodiments, the receiving node 112 may be further configured with one or more of the following four configurations.

[0208] In some embodiments, the receiving node 112 may be further configured to extract, by the RLC entity 131 of the receiving node 112, the one or more of the PDCP Control PDU and the first information as payload from the RLC Control PDU configured to be received. In some embodiments, the receiving node 112 may be further configured to send, by the RLC entity 131 of the receiving node 112, to the PDCP entity 132 of the receiving node 112, the RLC SDU configured to comprise the one or more of the PDCP Control PDU and the first information configured to be extracted as payload.

[0209] In some embodiments, the receiving node 112 may be further configured to decode, by the PDCP entity 132 of the receiving node 112, the one or more of the PDCP Control PDU and the first information configured to be received.

[0210] In some embodiments, the receiving node 112 may be further configured to perform, by the PDCP entity 132 of the receiving node 112, the second action based on the PDCP Control PDU configured to be decoded.

[0211] In some embodiments, one or more of: a) the first action may be configured to be performed based on the one or more PDU indexes configured to be comprised in the RLC Control PDU configured to be received, and b) the first action may be configured to comprise updating the one or more second variables configured to control the window of reception of the RLC entity 131 of the receiving device 112.

[0212] In some embodiments, one or more of: a) the second action may be configured to be performed based on the one or more PDU indexes configured to be comprised in the PDCP Control PDU or the first information configured to be received, and b) the second action may be configured to comprise updating the one or more third variables configured to control the window of reception of the PDCP entity 132 of the receiving device 112.

[0213] In some embodiments, the RLC Control PDU may be configured to lack the PDCP Control PDU as second payload, the PDCP Control PDU configured to be received may be configured to be included as the third information, and the RLC Control PDU may be configured to further comprise the fourth indication configured to indicate the type of the third information.

[0214] The embodiments herein in the receiving node 112 may be implemented through one or more processors, such as a processing circuitry 601 in the receiving node 112 depicted in Figure 6, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the receiving node 112. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the receiving node 112.

[0215] The processing circuitry 601 may be configured to, or operable to, perform the method actions according to Figure 3 and / or Figure 4. The receiving node 112 may further comprise a memory 602 comprising one or more memory units. The memory 602 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the receiving node 112.

[0216] In some embodiments, the receiving node 112 may receive information from, e.g., the transmitting node 111 , the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100, through a receiving port 603. In some embodiments, the receiving port 603 may be, for example, connected to one or more antennas in receiving node 112. Since the receiving port 603 may be in communication with the processing circuitry 601 , the receiving port 603 may then send the received information to the processing circuitry 601 . The receiving port 603 may also be configured to receive other information.

[0217] The processing circuitry 601 in the receiving node 112 may be further configured to transmit or send information to e.g., the transmitting node 111 , the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100, through a sending port 604, which may be in communication with the processing circuitry 601 , and the memory 602.

[0218] Those skilled in the art will also appreciate that the processing circuitry 601 described above may comprise a combination of analog and digital modules, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 601 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0219] Also, in some embodiments, the receiving node 112 may be configured to perform the actions of Figure 3 and / or Figure 4 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 601 .

[0220] The receiving node 112 may be configured to perform any of the Actions described in relation to Figure 4, and / or any of Figures 5-8, e.g., by means of the processing circuitry 601 within the receiving node 112, configured to perform any of such actions.

[0221] Thus, the methods according to the embodiments described herein for the receiving node 112 may be respectively implemented by means of a computer program 605 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 601 , cause the at least one processing circuitry 601 to carry out the actions described herein, as performed by the receiving node 112. The computer program 605 product may be stored on a computer-readable storage medium 606. The computer- readable storage medium 606, having stored there on the computer program 605, may comprise instructions which, when executed on at least one processing circuitry 601 , cause the at least one processing circuitry 601 to carry out the actions described herein, as performed by the receiving node 112. In some embodiments, the computer-readable storage medium 606 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 605 product may be stored on a carrier containing the computer program 605 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 606, as described above.

[0222] The receiving node 112 may comprise a communication interface configured to facilitate communications between the receiving node 112 and other nodes or devices, e.g., the transmitting node 111 , the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0223] In other embodiments, the receiving node 112 may also comprise a radio circuitry 607, which may comprise e.g., the receiving port 603 and the sending port 604. The radio circuitry 607 may be configured to set up and maintain at least a wireless connection with the transmitting node 111 , the virtual node 113, the RLC entity 121 of the transmitting node 111 , the PDCP entity 122 of the transmitting node 111 , the RLC entity 131 of the receiving node 112, PDCP entity 132 of the receiving node 112, or another network node, device or structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0224] Hence, embodiments herein also relate to the receiving node 112 comprising the processing circuitry 601 and the memory 602, said memory 602 containing instructions executable by said processing circuitry 601 , whereby the receiving node 112 is operative to perform the actions described herein in relation to the receiving node 112, e.g., in Figure 3 and / or Figure 4.

[0225] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description. As used herein, the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “and” term, may be understood to mean that only one of the list of alternatives may apply, more than one of the list of alternatives may apply or all of the list of alternatives may apply. This expression may be understood to be equivalent to the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “or” term.

Claims

CLAIMS:1 . A computer-implemented method, performed by a transmitting node (111) operating in a wireless communications network (100), the method comprising:- sending (207), to a receiving node (112) operating in the wireless communication network (100), a Radio Link Control, RLC, Control, Protocol Data Unit, PDU, comprising one or more of a PDCP Control PDU and first information indicating that the one or more data units have been discarded by a Packet Data Convergence Protocol, PDCP, entity (122) of the transmitting node (111) and second information indicating that one or more data units have been discarded by an RLC entity (121) of the transmitting node (111).

2. The method according to claim 1 , wherein the method further comprises:- receiving (203), by the RLC entity (121) of the transmitting node (111), from the PDCP entity (122) of the transmitting node (111), one or more of the PDCP Control PDU and the first information indicating the one or more data units that have been discarded by the PDCP entity (122) of the transmitting node (111), wherein the PDCP entity (122) is a transmitter of the one or more data units,- determining (205), by the RLC entity (121) of the transmitting node (111), whether or not the RLC entity (121) has one or more service data units associated to the one or more data units, and- generating (206), by the RLC entity (121) of the transmitting node (111), the RLC Control PDU by adding the received one or more of the PDCP Control PDU and the first information as one of payload and third information, and wherein the sent RLC Control PDU is the generated RLC Control PDU, wherein the generating (206) is performed with the proviso the RLC entity (121) determines that the RLC entity (121) has one or more service data units associated to the one or more data units.

3. The method according to claim 2, wherein the generating (206) comprises adding additional RLC control data to the RLC Control PDU, and wherein the sent RLC Control PDU comprises the additional RLC control data.

4. The method according to claim 2 or 3, wherein the method further comprises:- determining (201), by the PDCP entity (122) of the transmitting node (111), that one or more first variables controlling a window of transmission of the PDCP entity (122) are to be updated,- generating (202), by the PDCP entity (122), the one or more of the PDCP Control PDU and the first information based on a result of the determining (201) being that the one or more first variables controlling the window of transmission of the PDCP entity (122) of the transmitting node (111) are to be updated, the PDCP Control PDU indicating the one or more data units that have been discarded and that are to be processed as having been positively received by a PDCP entity (132) of the receiving node (112) by respective indexes of the one or more data units, and wherein the determining (205), by the RLC entity (121) of the transmitting node (111), of whether or not the RLC entity (121) of the transmitting node (111) has one or more service data units associated to the one or more data units is based on the indicated respective indexes, and- obtaining (204), by the RLC entity (121) of the transmitting node (111), a first indication from the PDCP entity (122) of the transmitting node (111) indicating a priority of the one or more of the PDCP Control PDU and the first information, and wherein the sending (207) of the RLC Control PDU is based on the indicated priority.

5. The method according to any of claims 1-4, wherein the RLC Control PDU has a format and wherein the format further comprises one or more of:- a first field indicating that the RLC Control PDU is a control PDU,- a second field indicating a type of the RLC Control PDU,- a third field indicating a first length of a first payload of the RLC control PDU, and- the RLC Control PDU first payload.

6. The method according to claim any of claims 2-5, wherein the RLC entity (121) receives the PDCP Control PDU from the PDCP entity (122) of the transmitting node (111), and wherein the RLC Control PDU comprises the PDCP Control PDU as a second payload.

7. The method according to claims 5 and 6, wherein the format further comprises one or more of:- the second field further indicating whether or not the RLC Control PDU comprises a PDCP Control PDU as payload,- one of: a fourth field indicating a second length of the PDCP control PDU, and a fifth field indicating a type of the PDCP Control PDU, and- one or more PDU indexes.

8. The method according to any of claims 2-7, wherein the RLC entity (121) of the transmitting node (111) receives the PDCP Control PDU from the PDCP entity (122) of the transmitting node (111), and wherein the PDCP Control PDU is one of a plurality of PDCP Control PDUs sent by the transmitting node (111), and wherein each of the PDCP Control PDUs in the plurality has a respective priority.

9. The method according to claim any of claims 2-5, wherein the RLC Control PDU lacks the PDCP Control PDU as payload, wherein the received PDCP Control PDU is included as third information, and wherein the RLC Control PDU further comprises a fourth indication indicating a type of the third information.

10. A computer-implemented method, performed by a receiving node (112), operating in wireless communications network (100), the method comprising:- receiving (301), directly or indirectly, from a transmitting node (111) operating in the wireless communication network (100), a Radio Link Control, RLC, Control, Protocol Data Unit, PDU, comprising one or more of a PDCP Control PDU and first information indicating that one or more data units have been discarded by a Packet Data Convergence Protocol, PDCP, entity (122) of the transmitting node (111) and are to be processed as having been positively received by a PDCP entity (132) of the receiving node (112), and second information indicating that one or more data units have been discarded by an RLC entity (121) of the transmitting node (111) and are to be processed as having been positively received by an RLC entity (131) of the receiving node (112).

11. The method according to claim 10, wherein the received RLC Control PDU comprises additional RLC control data.

12. The method according to any of claims 10-11 , wherein the receiving (301) of the RLC Control PDU is based on a priority.

13. The method according to any of claims 10-12, wherein the RLC Control PDU has a format and wherein the format further comprises one or more of:- a first field indicating that the RLC Control PDU is a control PDU,- a second field indicating a type of the RLC Control PDU,a third field indicating a first length of a first payload of the RLC control PDU, and the RLC Control PDU first payload.

14. The method according to claim any of claims 10-13, wherein the RLC Control PDU comprises the PDCP Control PDU as a second payload.

15. The method according to claim 14, wherein the PDCP Control PDU is one of a plurality of PDCP Control PDUs sent by the transmitting node (111), and wherein each of the PDCP Control PDUs in the plurality has a respective priority.

16. The method according to claims 13 and 14 or 15, wherein the format further comprises one or more of:- the second field further indicating whether or not the RLC Control PDU comprises a PDCP Control PDU as payload,- one of: a fourth field indicating a second length of the PDCP control PDU, and a fifth field indicating a type of the PDCP Control PDU, and- one or more PDU indexes.

17. The method according to any of claims 10-16, wherein the method further comprises:- decoding (302), by an RLC entity (131) of the receiving node (112), the received RLC Control PDU, and- performing (304), by the RLC entity (131) of the receiving node (112), a first action based on the decoded RLC Control PDU.

18. The method according to any of claims 10-17, wherein the method further comprises:- extracting (303), by the RLC entity (131) of the receiving node (112), the one or more of the PDCP Control PDU and the first information as payload from the received the RLC Control PDU, and- sending (305), by the RLC entity (131) of the receiving node (112), to the PDCP entity (132) of the receiving node (112), an RLC SDU comprising the extracted one or more of the PDCP Control PDU and the first information as pay load,- decoding (306), by the PDCP entity (132) of the receiving node (112), the received one or more of the PDCP Control PDU and the first information, and- performing (307), by the PDCP entity (132) of the receiving node (112), a second action based on the decoded PDCP Control PDU.

19. The method according to claim 16 and 17, wherein one or more of:- the first action is performed based on one or more PDU indexes comprised in the received RLC Control PDU, and- the first action comprises updating one or more second variables controlling a window of reception of the RLC entity (131) of the receiving device (112).

20. The method according to claim 16 and 18, wherein one or more of:- the second action is performed based on one or more PDU indexes comprised in the received PDCP Control PDU or the first information, and- the second action comprises updating one or more third variables controlling a window of reception of the PDCP entity (132) of the receiving device (112).

21. The method according to claim any of claims 10-13, wherein the RLC Control PDU lacks the PDCP Control PDU as second payload, wherein the received PDCP Control PDU is included as third information, and wherein the RLC Control PDU further comprises a fourth indication indicating a type of the third information.

22. A transmitting node (111) configured to operate in a wireless communications network (100), the transmitting node (111) being further configured to:- send, to a receiving node (112) configured to operate in the wireless communication network (100), a Radio Link Control, RLC, Control, Protocol Data Unit, PDU, configured to comprise one or more of a PDCP Control PDU and first information configured to indicate that the one or more data units have been discarded by a Packet Data Convergence Protocol, PDCP, entity (122) of the transmitting node (111) and second information configured to indicate that one or more data units have been discarded by an RLC entity (121) of the transmitting node (111).

23. The transmitting node (111) according to claim 22, wherein the transmitting node (111) is further configured to:- receive, by the RLC entity (121) of the transmitting node (111), from the PDCP entity (122) of the transmitting node (111), one or more of the PDCP Control PDU and the first information configured to indicate the one or more data units that have been discarded by the PDCP entity (122) of the transmitting node(111), wherein the PDCP entity (122) is configured to be a transmitter of the one or more data units,- determine, by the RLC entity (121) of the transmitting node (111), whether or not the RLC entity (121) has one or more service data units associated to the one or more data units, and- generate, by the RLC entity (121) of the transmitting node (111), the RLC Control PDU by adding the one or more of the PDCP Control PDU and the first information configured to be received as one of payload and third information, and wherein the RLC Control PDU configured to be sent is configured to be the RLC Control PDU configured to be generated, wherein the generating is configured to be performed with the proviso the RLC entity (121) determines that the RLC entity (121) has one or more service data units associated to the one or more data units.

24. The transmitting node (111) according to claim 23, wherein the generating is configured to comprise adding additional RLC control data to the RLC Control PDU, and wherein the RLC Control PDU configured to be sent is configured to comprise the additional RLC control data.

25. The transmitting node (111) according to claim 23 or 24, wherein the transmitting node (111) is further configured to:- determine, by the PDCP entity (122) of the transmitting node (111), that one or more first variables configured to control a window of transmission of the PDCP entity (122) are to be updated,- generate, by the PDCP entity (122), the one or more of the PDCP Control PDU and the first information based on a result of the determining being that the one or more first variables configured to control the window of transmission of the PDCP entity (122) of the transmitting node (111) are to be updated, the PDCP Control PDU being configured to indicate the one or more data units that have been discarded, and that are to be processed as having been positively received by a PDCP entity (132) of the receiving node (112), by respective indexes of the one or more data units, and wherein the determining, by the RLC entity (121) of the transmitting node (111), of whether or not the RLC entity (121) of the transmitting node (111) has one or more service data units associated to the one or more data units is configured to be based on the respective indexes configured to be indicated, and- obtain, by the RLC entity (121) of the transmitting node (111), a first indication from the PDCP entity (122) of the transmitting node (111) configured to indicate a priority of the one or more of the PDCP Control PDU and the firstinformation, and wherein the sending of the RLC Control PDU is configured to be based on the priority configured to be indicated.

26. The transmitting node (111) according to any of claims 22-25, wherein the RLC Control PDU is configured to have a format and wherein the format is further configured to comprise one or more of:- a first field configured to indicate that the RLC Control PDU is a control PDU,- a second field configured to indicate a type of the RLC Control PDU,- a third field configured to indicate a first length of a first payload of the RLC control PDU, and- the RLC Control PDU first payload.

27. The transmitting node (111) according to claim any of claims 23-26, wherein the RLC entity (121) is configured to receive the PDCP Control PDU from the PDCP entity (122) of the transmitting node (111), and wherein the RLC Control PDU is configured to comprise the PDCP Control PDU as a second payload.

28. The transmitting node (111) according to claims 26 and 27, wherein the format is further configured to comprise one or more of:- the second field being configured to further indicate whether or not the RLC Control PDU comprises a PDCP Control PDU as payload,- one of: a fourth field configured to indicate a second length of the PDCP control PDU, and a fifth field configured to indicate a type of the PDCP Control PDU, and- one or more PDU indexes.

29. The transmitting node (111) according to any of claims 23-28, wherein the RLC entity (121) of the transmitting node (111) is configured to receive the PDCP Control PDU from the PDCP entity (122) of the transmitting node (111), and wherein the PDCP Control PDU is configured to be one of a plurality of PDCP Control PDUs configured to be sent by the transmitting node (111), and wherein each of the PDCP Control PDUs in the plurality is configured to have a respective priority.

30. The transmitting node (111) according to claim any of claims 23-26, wherein the RLC Control PDU is configured to lack the PDCP Control PDU as payload, wherein the PDCP Control PDU configured to be received is configured to be included as thirdinformation, and wherein the RLC Control PDU is further configured to comprise a fourth indication configured to indicate a type of the third information.

31. A receiving node (112) configured to operate in wireless communications network (100), the receiving node (112) being further configured to:- receive, directly or indirectly, from a transmitting node (111) configured to operate in the wireless communication network (100), a Radio Link Control, RLC, Control, Protocol Data Unit, PDU, configured to comprise one or more of a PDCP Control PDU and first information configured to indicate that one or more data units have been discarded by a Packet Data Convergence Protocol, PDCP, entity (122) of the transmitting node (111) and are to be processed as having been positively received by a PDCP entity (132) of the receiving node (112), and second information configured to indicate that one or more data units have been discarded by an RLC entity (121) of the transmitting node (111) and are to be processed as having been positively received by an RLC entity (131) of the receiving node (112).

32. The receiving node (112) according to claim 31 , wherein the RLC Control PDU configured to be received is configured to comprise additional RLC control data.

33. The receiving node (112) according to any of claims 31-32, wherein the receiving of the RLC Control PDU is configured to be based on a priority.

34. The receiving node (112) according to any of claims 31-33, wherein the RLC Control PDU is configured to have a format and wherein the format is configured to further comprise one or more of:- a first field configured to indicate that the RLC Control PDU is a control PDU,- a second field configured to indicate a type of the RLC Control PDU,- a third field configured to indicate a first length of a first payload of the RLC control PDU, and- the RLC Control PDU first payload.

35. The receiving node (112) according to claim any of claims 31-34, wherein the RLC Control PDU is configured to comprise the PDCP Control PDU as a second payload.

36. The receiving node (112) according to claim 35, wherein the PDCP Control PDU is configured to be one of a plurality of PDCP Control PDUs configured to be sent by thetransmitting node (111), and wherein each of the PDCP Control PDUs in the plurality is configured to have a respective priority.

37. The receiving node (112) according to claims 34 and 35 or 36, wherein the format is further configured to comprise one or more of:- the second field further configured to indicate whether or not the RLC Control PDU comprises a PDCP Control PDU as payload,- one of: a fourth field configured to indicate a second length of the PDCP control PDU, and a fifth field configured to indicate a type of the PDCP Control PDU, and- one or more PDU indexes.

38. The receiving node (112) according to any of claims 31-37, wherein the receiving node (112) is further configured to:- decode, by an RLC entity (131) of the receiving node (112), the RLC Control PDU configured to be received, and- perform, by the RLC entity (131) of the receiving node (112), a first action based on the RLC Control PDU configured to be decoded.

39. The receiving node (112) according to any of claims 31-38, wherein the receiving node (112) is further configured to:- extract, by the RLC entity (131) of the receiving node (112), the one or more of the PDCP Control PDU and the first information as payload from the RLC Control PDU configured to be received,- send, by the RLC entity (131) of the receiving node (112), to the PDCP entity (132) of the receiving node (112), an RLC SDU configured to comprise the one or more of the PDCP Control PDU and the first information configured to be extracted as pay load,- decode, by the PDCP entity (132) of the receiving node (112), the one or more of the PDCP Control PDU and the first information configured to be received, and- perform, by the PDCP entity (132) of the receiving node (112), a second action based on the PDCP Control PDU configured to be decoded.

40. The receiving node (112) according to claim 37 and 38, wherein one or more of:- the first action is configured to be performed based on one or more PDU indexes configured to be comprised in the RLC Control PDU configured to be received, and- the first action is configured to comprise updating one or more second variables configured to control a window of reception of the RLC entity (131) of the receiving device (112).41 . The receiving node (112) according to claim 37 and 39, wherein one or more of:- the second action is configured to be performed based on one or more PDU indexes configured to be comprised in the PDCP Control PDU or the first information configured to be received, and- the second action is configured to comprise updating one or more third variables configured to control a window of reception of the PDCP entity (132) of the receiving device (112).

42. The receiving node (112) according to claim any of claims 31-34, wherein the RLC Control PDU is configured to lack the PDCP Control PDU as second payload, wherein the PDCP Control PDU configured to be received is configured to be included as third information, and wherein the RLC Control PDU is configured to further comprise a fourth indication configured to indicate a type of the third information.

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