TRANSMISSÃO DE DADOS, NÓ DE RECEPÇÃO DE DADOS, MÉTODO PARA TRANSMITIR DADOS ATRAVÉS DE UM CANAL SEM FIO, E MÉTODO PARA RECEBER DADOS ATRAVÉS DE UM CANAL SEM FIO

Abstract

Systems and methods for transmitting data over a wireless channel from a data transmission node to a data reception node in a communication system. The data transmission node has a second-layer processing circuit to obtain a second-layer service data unit (SDU) to be mapped onto a resource allocated for data transmission, and to generate a second-layer protocol data unit (PDU), which has an SDU and a second-layer control element, the second-layer control element placed after either of the second-layer SDUs, and the first-layer processing circuit to obtain the second-layer PDU generated by the second-layer processing circuit and map the second-layer PDU onto the resource allocated for data transmission.The data receiving node has a first-layer processing circuit to unmap a second-layer protocol data unit, PDU, from a resource allocated for data retrieval, and a second-layer processing circuit to obtain and analyze the second-layer PDU unmapped by the first-layer processing circuit, the second-layer PDU having a second-layer service data unit, SDU, and a second-layer control element, the second-layer control element following either of the second-layer SDU.

Description

Descriptive Report of the Invention Patent for a KNOT Data transmission, data receiving node, method for transmitting data through a wireless channel, and method for receiving data through a wireless channel. FIELD OF TECHNIQUE

[0001] The present invention relates to a multi-layered transmission and reception processing in a communication system as well as the corresponding transmission devices, methods and programs. FUNDAMENTALS

[0002] Third-generation (3G) mobile systems based on WCDMA radio access technology are being developed on a large scale around the world. A first step in improving or developing this technology requires introducing High-Speed ​​Downlink Packet Access (HSDPA) and an enhanced uplink, also referred to as High-Speed ​​Uplink Packet Access (HSUPA), providing a highly competitive radio access technology. In order to be prepared to further increase user demands and to be competitive with new radio access technologies, 3GPP introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to meet carrier needs for high-speed data and media transport as well as high-capacity voice support over the next decade. The ability to provide high bit rates is a key measure for LTE.The Long Term Evolution (LTE) Work Item (WI) specification, named Enhanced UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN), is finalized as Release 8 (Rel. 8 LTE). The LTE system. Petition 870240080006, dated 09 / 19 / 2024, page 8 / 139 2 / 121 represents efficient packet-based radio access and radio access networks that provide full IP-based functionality with low latency and low cost. In LTE, multiple scalable transmission bandwidths are specified such as 1.4, 3.0, 5.0, 10.0, 15.0 and 20.0 MHz, in order to achieve flexible system development using a given spectrum. In the downlink, Orthogonal Frequency Division Multiplexing (OFDM) based radio access was adopted due to its inherent immunity to multipath interference (MPI) due to a low symbol rate, the use of a cyclic prefix (CP) and its affinity for different transmission bandwidth arrangements.A radio access based on Single Carrier Frequency Division Multiple Access (SC-FDMA) was adopted in the uplink, as the provision of wide area coverage was prioritized over peak data rate enhancement considering the restricted transmission power of the user equipment (UE). Many key packet radio access techniques are employed, including multiple input multiple output channel transmission (MIMO) techniques, and a highly efficient control signaling structure is achieved in Rel. 8 LTE. LTE Architecture

[0003] The general architecture is shown in Figure 1, and a more detailed representation of the E-UTRAN architecture is given in Figure 2. E-UTRAN consists of eNBs, which provide E-UTRAN user plane protocol terminations (PDCP / RLC / MAC / PHY) and control plane (RRC) in the UE direction. The eNB hosts the Physical (PHY), Medium Access Control (MAC), Radio Connection Control (RLC), and Packet Data Control Protocol (PDCP) layers, which include user plane header compression and encryption functionality. It also offers a functionality Petition 870240080006, dated 09 / 19 / 2024, page 9 / 139 3 / 121 Radio Resource Control (RRC) which corresponds to the control plane. It performs multiple functions including radio resource management, admission control, scheduling, enforcement of negotiated UL QoS, cell information transmission, encoding / decryption of user plane data, and control and compression / decompression of DL / UL user plane packet headers. eNBs are also connected via the X2 interface. eNBs are also connected via the S1 interface on the EPC (Developed Packet Core), more specifically to the MME (Mobility Management Entity) via S1-MME and to the Server Port (S-GW) via S1-U. The S1 interface supports a many-to-many relationship between MMEs / Server Ports and eNBs.The SGW routes and transfers user data packets while also acting as the mobility anchor for the user plane during inter-eNB transfers and as the anchor for mobility between LTE and other 3GPP technologies (terminating the S4 interface and transferring traffic between 2G / 3G systems and PDN GW). For idle UEs, the SGW terminates the DL data path and triggers paging when DL data arrives at the UE. It manages and stores UE contexts, for example, IP carrier service parameters, internal network routing information. It also performs user traffic replication in case of lawful interception.

[0004] The MME is the key control node for the LTE access network. It is responsible for idle mode UE tracking and paging procedures, including retransmissions. It is involved in the carrier activation / deactivation process and is also responsible for choosing the SGW for a UE on initial connection and at the time of intra-LTE transfer involving Core Network (CN) node relocation. It is also Petition 870240080006, dated 09 / 19 / 2024, page 10 / 139 4 / 121 is responsible for authenticating the user (interacting with the HSS). The Non-Access Stratum (NAS) signaling terminates at the MME and is also responsible for generating and allocating temporary identities for UEs. This verifies the UE's authorization to roam on the service provider's Public Terrestrial Mobile Network (PLMN) and enforces UE roaming restrictions. The MME is the termination point in the network for encryption / integrity protection for NAS signaling and handles security key management. Lawful interception of signaling is also supported by the MME. The MME also provides the control plane function for mobility between LTE and 2G / 3G access networks with the S3 interface terminating at the SGSN MME. The MME also terminates the S6a interface towards the home HSS for roaming UEs.

[0005] The downlink component carrier of a system 3GPP LTE is subdivided in the time-frequency domain into so-called subframes. In 3GPP LTE, each subframe is divided into two downlink intervals, where the first downlink interval comprises the control channel region (PDCCH region) within the first OFDM symbols. Each subframe consists of a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8)), where each OFDM symbol spans the entire bandwidth of the component carrier. The OFDM symbols thus each consist of a number of modulation symbols transmitted over their respective subcarriers.

[0006] Assuming a multi-carrier communication system, for example employing OFDM, as, for example, used in 3GPP Long Term Evolution (LTE), the smallest unit of resources that can be assigned to the programmer is a resource block. A physical resource block (PRB) is defined as Petition 870240080006, dated 09 / 19 / 2024, page 11 / 139 5 / 121 consecutive OFDM symbols in the time domain (e.g., 7 OFDM symbols) and consecutive subcarriers in the frequency domain (e.g., 12 subcarriers for one component carrier). In 3GPP LTE (Release 8), a physical feature block thus consists of feature elements corresponding to a time range and 180 kHz in the frequency domain (for further details on the downlink feature grid, see for example 3GPP TS 36.211, Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)(NPL 1), section 6.2, available at http: / / www.3gpp.org and incorporated herein by reference).

[0007] A subframe consists of two intervals, so there are 14 OFDM symbols in a subframe when a so-called normal CP (cyclic prefix) is used, and 12 OFDM symbols in a subframe when a so-called extended CP is used. For the sake of terminology, the following time-frequency features equivalent to the same consecutive subcarriers spanning a total subframe are called a feature block pair or equivalent RB pair or PRB pair.

[0008] The term component carrier refers to a combination of several resource blocks in the frequency domain. In future versions of LTE, the term component carrier is no longer used; instead, the terminology is changed to cell, which refers to a combination of downlink and optionally uplink resources. The connection between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources is indicated in the system information transmitted on the downlink resources. Similar assumptions for the component carrier structure apply to later versions as well. Overview of the OSI Layer Petition 870240080006, dated 09 / 19 / 2024, page 12 / 139 6 / 121

[0009] Figure 3A provides a brief overview of a layer model on which further discussion of LTE architecture is based.

[00010] The Open Systems Interconnection Reference Model (OSI Model or OSI Reference Model) is an abstract, layered description for computer network communication and protocol design. The OSI model divides the functions of a system into a series of layers. Each layer has the property of only using the functions of the layer below it and only exporting functionality to the layer above. A system that implements protocol behavior consisting of a series of these layers is known as a 'protocol stack' or 'stack'. Its main characteristic lies in the junction between the layers, which dictates the specifications on how one layer interacts with another. This means that a layer written by one vendor can operate with a layer from another. For the purposes of this description, only the first three layers will be described in more detail below.

[00011] The main purpose of the physical layer or layer 1 is the transfer of information (bits) over a specific physical medium (e.g., coaxial cables, twisted pairs, optical fibers, air interface, etc.). This converts or modulates data into signals (or symbols) that are transmitted over a communication channel.

[00012] The purpose of the data link layer (or Layer 2) is to model the flow of information in a way that is compatible with the specific physical layer by breaking the input data into data frames (Segmentation and Reassembly (SAR) functions). Furthermore, it can detect and correct potential transmission errors by requesting a retransmission of a lost frame. It typically provides an addressing mechanism and may offer algorithms. Petition 870240080006, dated 09 / 19 / 2024, page 13 / 139 7 / 121 flow control in order to align the data rate with the receiver capacity. If a shared medium is concurrently used by multiple transmitters and receivers, the data link layer typically provides mechanisms to regulate and control access to the physical medium.

[00013] Because there are numerous functions offered by the data link layer, the data link layer is often subdivided into sublayers (e.g., RLC and MAC layers in UMTS). Typical examples of Layer 2 protocols are PPP / HDLC, ATM, frame transfer for fixed-line networks, and RLC, LLC, or MAC for wireless systems. More detailed information on the PDCP, RLC, and MAC sublayers of Layer 2 will be provided later. It is noted that in this application, sublayers are also referred to as layers, and thus the term layer used here does not necessarily mean an OSI model layer.

[00014] The network layer or Layer 3 provides the functional and procedural means to transfer variable-length packets from a source to a destination across one or more networks while maintaining the quality of service required by the transport layer. Typically, the main purposes of the network layer are, among others, to perform network routing, network fragmentation, and congestion control functions. The main examples of network layer protocols are the Internet Protocol IP or X.25.

[00015] With regard to Layers 4 through 7, it should be noted that depending on the application and service, it is sometimes difficult to assign an application or service to a specific layer of the OSI model, since applications and services operating above Layer 3 often implement a variety of functions that must Petition 870240080006, dated 09 / 19 / 2024, page 14 / 139 8 / 121 can be assigned to different layers of the OSI model. Therefore, especially in TCP (UDP) / IP-based networks, Layer 4 and above is sometimes combined to form a so-called application layer. Layer Services and Data Exchange

[00016] In the following, the terms Service Data Unit (SDU) and Protocol Data Unit (PDU) as used herein are defined in connection with Figure 3B. In order to formally describe in a generic way the exchange of packets between layers in the OSI model, the entities of SDU and PDU have been introduced. An SDU is a unit of information (data / information block) transmitted from a protocol in layer N+1 that requests a service from a protocol located in layer N through a so-called service access point (SAP). A PDU is a unit of information exchanged between peer processes in the transmitter and receiver of the same protocol located in the same layer N.

[00017] A PDU is generally formed by a payload portion consisting of the processed version of the received SDU(s) preceded by a Layer N-specific header and optionally terminated by a trailer. Since there is no direct physical connection (except for Layer 1) between these peer processes, a PDU is forwarded to Layer N-1 for processing. Therefore, a Layer N PDU is, from the point of view of Layer N-1, an SDU.

[00018] LTE User Plane (U-plane, UP) and Control Plane (C-plane, CP) Protocols:

[00019] The LTE Layer 2 user plane / control plane protocol stack comprises three sublayers: PDCP, RLC, and MAC. Petition 870240080006, dated 09 / 19 / 2024, page 15 / 139 9 / 121

[00020] As explained earlier, on the transmission side, each layer receives an SDU from a higher layer to which the layer provides a service and sends a PDU to the layer below. The RLC layer receives packets from the PDCP layer. These packets are called PDCP PDUs from a PDCP perspective and represent RLC SDUs from an RLC perspective. The RLC layer creates packets which are provided to the layer below, that is, the MAC layer. The packets provided by RLC to the MAC layer are RLC PDUs from an RLC perspective and MAC SDUs from a MAC perspective. On the reception side, the process is reversed, with each layer passing SDUs to the layer above, where these are received as PDUs.

[00021] While the physical layer essentially provides a bitpipe, protected by turbo coding and cyclic redundancy check (CRC), connection layer protocols enhance service to higher layers through increased reliability, security, and integrity. Furthermore, the connection layer is responsible for multi-user medium access and scheduling. One of the main challenges for LTE connection layer design is providing the required levels of reliability and latency for Internet Protocol (IP) data streams with their wide range of different services and data rates. Specifically, protocol over-processing must scale. It is widely assumed that Voice over IP (VoIP) streams can tolerate latencies on the order of 100 ms and packet losses of up to 1%. On the other hand, it is well known that TCP file downloads perform best over connections with low bandwidth latency products.Consequently, downloads at very high data rates (e.g., 100 Mb / s) require even lower latency and, moreover, are more susceptible to packet loss. Petition 870240080006, dated 09 / 19 / 2024, page 16 / 139 10 / 121 IP traffic is more common than VoIP traffic.

[00022] In general, this is achieved by the three sublayers in the LTE connection layer that are partially interconnected. The Packet Data Convergence Protocol (PDCP) sublayer is primarily responsible for IP header compression and encoding. Additionally, it supports lossless mobility in the case of inter-eNB transfers and provides integrity protection for higher-layer control protocols. The Radio Connection Control (RLC) sublayer primarily comprises ARQ functionality and supports data segmentation and concatenation. The latter two minimize excessive protocol processing independent of the data rate. Finally, the Media Access Control (MAC) sublayer provides HARQ and is responsible for the functionality required for media access, such as scheduling and random access operations.

[00023] Specifically, the Media Access Control (MAC) layer is the lowest sublayer in the Layer 2 architecture of the LTE radio protocol stack and is defined by, for example, the 3GPP TS 36.321 (NPL 2) technical standard, current version 13.0.0. The connection to the physical layer below is via transport channels, and the connection to the RLC layer above is via logical channels. The MAC layer, therefore, performs multiplexing and demultiplexing between logical channels and transport channels: the MAC layer on the transmission side constructs MAC PDUs, known as transport blocks, from MAC SDUs received via logical channels, and the MAC layer on the reception side retrieves MAC SDUs from MAC PDUs received via transport channels.

[00024] The MAC layer provides a data transfer service (see subclauses 5.4 and 5.3 of TS 36.321 incorporated herein by reference) to the RLC layer through logical channels, which Petition 870240080006, dated 09 / 19 / 2024, page 17 / 139 11 / 121 are either logical control channels which carry control data (e.g., RRC signaling) or logical traffic channels which carry user plane data. On the other hand, MAC layer data is exchanged with the physical layer through transport channels, which are classified as downlink or uplink. Data is multiplexed into transport channels depending on how it is transmitted through the air. In addition to MAC SDUs, MAC PDUs may also include MAC control elements of various types and padding, if necessary.

[00025] The Physical Layer is responsible for the actual transmission of data and control information across the air interface; that is, the Physical Layer carries all the information from the MAC transport channels over the air interface on the transmission side. Some of the important functions performed by the Physical Layer include encoding and modulation, connection adaptation (AMC), power control, cell search (for initial synchronization and transfer purposes), and other measures (within LTE systems and between systems) for the RRC layer. The Physical Layer performs transmissions based on transmission parameters such as the modulation scheme, the encoding rate (i.e., the modulation and encoding scheme, MCS), the number of physical resource blocks, etc. More information on the operation of the physical layer can be found in the 3GPP 36.213 technical standard, current version 13.0.0 (NPL 3), incorporated herein by reference.

[00026] The Radio Resource Control (RRC) layer controls communication between a UE and an eNB on the radio interface and the mobility of a UE moving through various cells. The RRC protocol also supports the transfer of NAS information. For UEs in RRC_IDLE, RRC supports network notification of incoming calls. RRC connection control covers all Petition 870240080006, dated 09 / 19 / 2024, page 18 / 139 12 / 121 procedures relating to the establishment, modification and release of an RRC connection, including paging, metering and reporting configuration, radio resource configuration, initial security activation and establishment of Signaling Radio Carriers (SRBs) and radio carriers that carry user data (Data Radio Carriers, DRBs).

[00027] The radio connection control (RLC) sublayer primarily comprises ARQ functionality and supports data segmentation and concatenation; that is, the RLC layer performs framing of RLC SDUs to fit them into the size specified by the MAC layer. The latter two minimize protocol processing overhead regardless of data rate. The RLC layer is connected to the MAC layer via logical channels. Each logical channel carries different types of traffic. The layer above the RLC layer is typically the PDCP layer, but in some cases this is the RRC layer; that is, RRC messages transmitted over the BCCH (Transmission Control Channel), PCCH (Page Control Channel), and CCCH (Common Control Channel) logical channels do not require security protection and thus go directly to the RLC layer, bypassing the PDCP layer. RLC Retransmission Protocol

[00028] When the RLC is configured to request retransmission of missing PDUs, it is said to be operating in Acknowledged Mode (AM). This is similar to the corresponding mechanism used in WCDMA / HSPA. In total, there are three operating modes for RLC: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). Each RLC entity is configured by RRC to operate in one of these modes.

[00029] In Transparent Mode, no protocol payload is Petition 870240080006, dated 09 / 19 / 2024, page 19 / 139 13 / 121 added to the RLC SDUs received from the higher layer. In special cases, transmission with limited segmentation / reassembly capability may be performed. It needs to be negotiated in the radio carrier configuration procedure if segmentation / reassembly is used. Transparent mode is, for example, used for services that are very sensitive to delay, such as speech.

[00030] In Unconfirmed Mode, data delivery is not guaranteed, as no retransmission protocol is used. The PDU structure includes sequence numbers for integrity observations at higher layers. Based on the RLC sequence number, the receiving UM RLC entity can perform reordering of the received RLC PDUs. Segmentation and concatenation are provided through header fields added to the data. The RLC entity in Unconfirmed mode is unidirectional, as there are no defined associations between uplink and downlink.If erroneous data is received, the corresponding PDUs are discarded or marked depending on the configuration. At the transmitter, RLC SDUs that are not transmitted within a certain time specified by a timer are discarded and removed from the temporary transmission storage. RLC SDUs received from the higher layer are segmented / concatenated into RLC PDUs on the sender side. On the receiver side, a reassembly is performed accordingly. Unconfirmed mode is used for services where error-free delivery is of lesser importance compared to short delivery time, for example, for certain signaling and RRC procedures, a cell transmission service such as MBMS and Voice over IP (VoIP).

[00031] In Confirmed Mode, the RLC layer supports error correction through an Automatic Retry Request protocol. Petition 870240080006, dated 09 / 19 / 2024, page 20 / 139 14 / 121 (ARQ), and is typically used for IP-based services such as file transfer where the provision of error-free data is of primary interest. RLC retransmissions are, for example, based on RLC status reports, i.e., ACK / NACK, received from the peer RLC receiving entity. The confirmed mode is designed for reliable packet data transport via retransmission in the presence of high air interface bit error rates. In the case of erroneous or lost PDUs, a retransmission is conducted by the sender upon receipt of an RLC status report from the receiver.

[00032] ARQ is used as a retransmission scheme for retransmitting erroneous or missing PDUs. For example, by monitoring incoming sequence numbers, the receiving RLC entity can identify missing PDUs. Then, an RLC status report can be generated on the receiving RLC side and returned to the transmitting RLC entity, requesting retransmission of missing or unsuccessfully decoded PDUs. The RLC status report can also be queried by the transmitter; that is, the query function is used by the RLC transmitter to obtain a status report from the RLC receiver, in order to inform the RLC transmitter of the temporary storage status of the received PDU. The status report provides positive acknowledgments (ACKs) or negative acknowledgments (NACKs) on RLC Data PDUs or portions thereof, up to the last RLC Data PDU whose HARQ reordering is complete.The RLC receiver triggers a status report if a PDU with the query field set to '1' or when an RLC Data PDU is detected as missing. There are certain triggers defined in subclause 5.2.3 of TS 36.322 (NPL 4), current version 13.0.0, incorporated here by reference, that trigger a query for a report. Petition 870240080006, dated 09 / 19 / 2024, p. 21 / 139 15 / 121 status RLC on the RLC transmitter. On the transmitter, transmission is only allowed for PDUs within the transmission window, and the transmission window is only updated by the RLC status report. Therefore, if the RLC status report is delayed, the transmission window cannot be advanced and transmission could be stalled. The receiver sends the RLC status report to the sender when triggered. Layer 1 / Layer 2 Control Signaling

[00033] In order to inform programmed users about their allocation status, transport format, and other transmission-related information (e.g., HARQ information, transmission power control (TPC) commands), an L1 / L2 control signal is transmitted over the downlink along with the data. The L1 / L2 control signal is multiplexed with the downlink data in a subframe, assuming that user allocation can change from subframe to subframe. It should be noted that user allocation could also be performed on a TTI (Transmission Time Interval) basis, where the TTI length can be a multiple of the subframes. The TTI length can be fixed in a service area for all users, can be different for different users, or can even be dynamic for each user. Generally, the L1 / L2 control signal only needs to be transmitted once per TTI.Without loss of generality, the following assumes that a TTI is equivalent to a subframe.

[00034] L1 / L2 control signaling is transmitted over the Physical Downlink Control Channel (PDCCH). A PDCCH carries a message called Downlink Control Information (DCI), which in most cases includes resource assignments and other control information for a mobile terminal or Petition 870240080006, dated 09 / 19 / 2024, page 22 / 139 16 / 121 groups of EUs. Several PDCCHs can be transmitted in a subframe.

[00035] Generally, the information sent in L1 / L2 control signaling to allocate uplink or downlink radio resources (specifically LTE(-A) Release 10) can be categorized into the following items: - User identity, indicating the user who is assigned. This is typically included in the checksum, masking the CRC with the user identity; - Resource allocation information, indicating the resources (e.g., Resource Blocks, RBs) to which a user is allocated. Alternatively, this information is referred to as resource block allocation (RBA). Note that the number of RBs to which a user is allocated can be dynamic; - Carrier indicator, which is used if a control channel transmitted over a first carrier allocates resources pertaining to a second carrier, i.e., resources on a second carrier or resources relating to a second carrier; (cross-carrier programming); - Modulation and coding scheme that determines the modulation scheme and coding rate employed; - HARQ information, such as a new data indicator (NDI) and / or a redundancy version (RV) that is specifically useful in retransmissions of data packets or parts thereof; - Power control commands to adjust the transmission power of uplink data or control information transmission; - Reference signal information such as Petition 870240080006, dated 09 / 19 / 2024, page 23 / 139 17 / 121 cyclic shift applied and / or orthogonal coverage code index, which must be used for transmission or reception of assignment-related reference signals; - An uplink or downlink assignment index used to identify an assignment order, which is particularly useful in TDD systems; - Hopping information, for example, an indication of whether and how to apply resource hopping in order to increase frequency diversity; - CSI request, which is used to trigger the transmission of channel state information on an assigned resource; and - Multiple cluster information, which is a beacon used to indicate and control whether transmission occurs in a single cluster (contiguous set of RBs) or in multiple clusters (at least two non-contiguous sets of contiguous RBs). Multiple cluster allocation was introduced by 3GPP LTE-(A) Release 10.

[00036] It should be noted that the above list is not exhaustive, and not all items of information mentioned need to be present in every PDCCH transmission depending on the DCI format that is used.

[00037] Downlink control information occurs in several formats that differ in total size and also in the information contained in their fields, as mentioned above. The different DCI formats that are currently defined for LTE are as follows and described in detail in 3GPP TS 36.212, Multiplexing and channel coding, section 5.3.3.1 (current version v13.0.0 (NPL 5) available at http: / / www.3gpp.org and incorporated here by reference). For example, the following Formats of Petition 870240080006, dated 09 / 19 / 2024, page 24 / 139 18 / 121 DCIs can be used to allocate a resource grant to the uplink. - Format 0: DCI Format 0 is used for transmitting resource grants to PUSCH, using single-antenna port transmissions in uplink 1 or 2 transmission mode. - Format 4: DCI Format 4 is used for PUSCH programming, utilizing closed-loop spatial multiplexing transmissions in uplink 2 transmission mode. LTE Uplink Access Scheme

[00038] The uplink scheme allows both scheduled access, i.e., controlled by eNB, and contention-based access.

[00039] In the case of scheduled access, the UE is allocated a certain frequency resource for a certain time (i.e., a time / frequency resource) for uplink data transmission. However, some time / frequency resources may be allocated for contention-based access. Within these time / frequency resources, UEs may transmit without first being scheduled. A scenario where a UE is performing contention-based access is, for example, random access, i.e., when the UE is performing an initial access to a cell or to request uplink resources.

[00040] For scheduled access, the Node B programmer assigns a user a single frequency / time resource for uplink data transmission. More specifically, the programmer determines which UE(s) are allowed to transmit, on which physical channel (frequency) resources, and the corresponding transport format to be used by the mobile terminal for transmission.

[00041] The allocation information is signaled to the UE via the scheduling grant, sent over the channel of Petition 870240080006, dated 09 / 19 / 2024, page 25 / 139 19 / 121 L1 / L2 control. The programming grant message contains information about which part of the frequency band the UE is permitted to use, the validity period of the grant, and the transport format the UE needs to use for the next uplink transmission. The shortest validity period is a subframe. Additional information may also be included in the grant message, depending on the selected scheme. Only UE grants are used to grant the right to transmit over UL-SCH (i.e., there are no UE grants per RB). Therefore, the UE needs to distribute the allocated resources among the radio carriers according to certain rules. Unlike HSUPA, there is no UE-based transport format selection.The eNB decides the transport format based on several pieces of information, such as channel quality feedback, reported programming information, and QoS information, and the UE must follow the selected transport format.

[00042] The usual scheduling method is dynamic scheduling, using downlink assignment messages for allocating downlink transmission resources and uplink grant messages for allocating uplink transmission resources; these are usually valid for specific single subframes. These are transmitted over PDCCH using UE's C-RNTI. Dynamic scheduling is efficient for types of services where traffic is intermittent and rate-dynamic, such as TCP.

[00043] In addition to dynamic scheduling, a persistent schedule is defined, which allows radio resources to be semi-statically configured and allocated to a UE for a longer period of time than a subframe, thus avoiding the need for specific downlink assignment messages or uplink grant messages over the PDCCH for each Petition 870240080006, dated 09 / 19 / 2024, page 26 / 139 20 / 121 subframe. Persistent scheduling is useful for services such as VoIP, where data packets are small, periodic, and semi-static in size. Thus, the PDCCH over-processing is significantly reduced compared to dynamic scheduling. Logical Channel Prioritization Procedure, LCP

[00044] For the uplink, the process by which the UE creates a MAC PDU to transmit using the allocated radio resources is fully standardized; this is designed to ensure that the UE satisfies the QoS of each configured radio carrier in a way that is optimal and consistent across different UE implementations. Based on the uplink transmission resource allocation message signaled over the PDCCH, the UE needs to decide on the amount of data for each logical channel to be included in the new MAC and, if necessary, also allocate space for a MAC Control Element.

[00045] In constructing a MAC PDU with data from multiple logical channels, the simplest and most intuitive method is the absolute priority-based method, where the MAC PDU space is allocated to logical channels in descending order of logical channel priority. That is, data from the highest priority logical channel is served first in the MAC PDU, followed by data from the next highest priority logical channel, continuing until the MAC PDU space runs out. Although the absolute priority-based method is quite simple in terms of UE implementation, it sometimes leads to data exhaustion for low-priority logical channels. Exhaustion means that data from low-priority logical channels cannot be transmitted because data from high-priority logical channels occupies all the MAC PDU space. Petition 870240080006, dated 09 / 19 / 2024, page 27 / 139 21 / 121

[00046] In LTE, a Prioritized Bit Rate (PBR) is defined for each logical channel in order to transmit data in order of importance, but also to avoid exhaustion of data with lower priority. The PBR is the minimum guaranteed data rate for the logical channel. Even if the logical channel has low priority, at least a small amount of MAC PDU space is allocated to guarantee the PBR. Thus, the exhaustion problem can be avoided by using the PBR.

[00047] Building a MAC PDU with PBR consists of two rounds. In the first round, each logical channel is served in descending order of logical channel priority, but the amount of data from each logical channel included in the MAC PDU is initially limited to the amount corresponding to the configured PBR value of the logical channel. After all logical channels have been served up to their PBR values, if there is remaining space in the MAC PDU, the second round is executed. In the second round, each logical channel is again served in descending order of priority. The main difference for the second round compared to the first round is that each lower priority logical channel can be allocated MAC PDU space only if all higher priority logical channels have no more data to transmit.

[00048] A MAC PDU can include not only the MAC SDUs of each configured logical channel, but also a MAC CE. Except for a Fill BSR, the MAC CE has a higher priority than a MAC SDU of the logical channels because it controls the operation of the MAC layer. Thus, when a MAC PDU is composed, the MAC CE, if it exists, is the first to be included, and the remaining space is used for the MAC SDUs of the logical channels. Then, if additional space is left and it is large enough to include a BSR, a Fill BSR is triggered and Petition 870240080006, dated 09 / 19 / 2024, p. 28 / 139 22 / 121 included in the MAC PDU.

[00049] Logical Channel Prioritization is standardized, for example, in 3GPP TS 36.321 (version v12.4.0) in subclause 5.4.3.1 incorporated herein. It is up to the UE implementation to decide in which MAC PDU a MAC control element is included when the UE is requested to transmit multiple MAC PDUs in a TTI. Temporary Storage Status Report

[00050] UE Temporary Storage Status Reports (BSRs) for the eNodeB are used to assist the eNodeB in allocating uplink resources, i.e., uplink scheduling. For downlink, the eNB scheduler is obviously aware of the amount of data to be provided to each UE; however, for uplink, since scheduling decisions are made on the eNB and temporary storage for the data is on the UE, BSRs need to be sent from the UE to the eNB to indicate the amount of data that needs to be transmitted over the UL-SCH.

[00051] The Temporary Storage Status Report MAC control elements for LTE consist of either: a long BSR (with four temporary storage size fields corresponding to LCG IDs # 0-3) or a short BSR (with one LCG ID field and one corresponding temporary storage size field). The temporary storage size field indicates the total amount of data available across all logical channels in a logical channel group, and is indicated in number of encoded bytes as an index of different temporary storage size levels (see also 3GPP TS 36.321 v 12.4.0 Chapter 6.1.3.1, incorporated herein by reference).

[00052] Which of each of the short or long BSRs is transmitted by the UE depends on the transmission resources available in a transport block, in how many logical channel groups have storage. Petition 870240080006, dated 09 / 19 / 2024, page 29 / 139 23 / 121 temporary non-empty and in if a specific event is triggered in the UE. The long BSR reports the amount of data for four groups of logical channels, while the short BSR indicates the amount of data stored for only the highest group of logical channels.

[00053] The reason for introducing the concept of logical channel groups is that although the UE can have more than four logical channels configured, reporting the temporary storage status for each individual logical channel would cause excessive signaling processing. Therefore, the eNB assigns each logical channel to a logical channel group; preferably, logical channels with the same / similar QoS requirements should be allocated within the same logical channel group.

[00054] If the UE does not have uplink resources allocated to include a BSR in the transport block when a BSR is triggered, the UE sends a scheduling request (SR) to the eNodeB in order to be allocated uplink resources to transmit the BSR. Either a single-bit scheduling request is sent over the Physical Uplink Control Channel (PUCCH) (dedicated scheduling request, D-SR), or the random access procedure (RACH) is executed to request an allocation of an uplink radio resource to send a BSR. Other MAC Control Elements

[00055] MAC Control elements are used for point-to-point MAC Level signaling.

[00056] There are additional MAC control elements defined in LTE. These MAC control elements can refer to either uplink or downlink transmission.

[00057] Power Tolerance Reporting (PHR) MAC control elements are used by the UE to report available power tolerance and then used at the base station to Petition 870240080006, dated 09 / 19 / 2024, page 30 / 139 24 / 121 determines how much more uplink bandwidth per subframe an UE is able to use. These elements are provided in the uplink to the programming node (eNB) to allow it to schedule uplink transmission resources for different UEs and prevent resources from being allocated to a UE that is unable to use them due to its power limitations. Currently, PHR can only be sent in subframes in which an UE has an uplink transmission grant, i.e., with uplink data transmission.

[00058] Enable / Disable MAC control elements are used for enabling / disabling SCells, i.e., secondary server cells providing additional resources to the primary server cell's resources. To allow for reasonable UE battery consumption when carrier aggregation is configured, the SCell enable / disable mechanism is supported. If the UE is configured with one or more SCells, the eNodeB can enable and disable the configured SCells. Enable / Disable does not apply to the PCell. The CE MAC carries a bitmap for enabling and disabling SCells: set to 1 denotes activation of the corresponding SCell, while a bit set to 0 denotes deactivation. With the bitmap, SCells can be enabled and disabled individually, and a single enable / disable command can enable / disable a subset of the SCells.

[00059] Cell Radio Network Temporary Identifier (C-RNTI) MAC control elements control elements that allow the UE to transmit its own C-RNTI during a random access procedure for the purpose of contention resolution.

[00060] EU Contention Resolution Identity MAC Control Elements are used by eNodeB to Petition 870240080006, dated 09 / 19 / 2024, page 31 / 139 25 / 121 transmitting the uplink CCCH (Common Control Channel) is due to the UE having sent it during the random access procedure for the purpose of contention resolution when the UE does not have CRNTI.

[00061] The DRX command MAC control element is used by the eNodeB to transmit the downlink PRX command to the UEs.

[00062] The time advance command MAC control element is used by the eNodeB to transmit the time advance command to the UEs for uplink time alignment.

[00063] MBMS dynamic programming information MAC control element is transmitted to each MCH to inform MBMS-capable UEs about data transmission programming over MTCH.

[00064] For more information on the MAC control elements listed above, see 3GPP TS 36.321, V13.3.0 section 6.1.3 (incorporated herein by reference). A special LCID is allocated for each type of MAC control element. L1 / L2 processing

[00065] Figure 4 exemplifies the data flow of an IP packet through the connection layer protocols to the physical layer. The figure shows that each protocol sublayer adds its own protocol header to the data units as well as the mapping of the transport block onto a subframe. The transport block (TB) denotes the MAC PDU that is mapped onto the physical layer.

[00066] The mapping of the transport block over the subframe in LTE is performed within a so-called transmission time interval (TTI). Generally, a single transport block is mapped in one TTI to one subframe in the case of Petition 870240080006, dated 09 / 19 / 2024, page 32 / 139 26 / 121 single input single output (SISO), i.e., the transmitter and receiver operating with one antenna. In the case of MIMO / MISO (multiple input multiple output / multiple input single output), two code words corresponding to two transport blocks can be mapped in a TTI to the physical resources. In general, more than two transport blocks can be considered for mapping.

[00067] LTE L2 functions are summarized in the following table: Table 1 Table 1: LTE L2 functions (Tx side) Uplink Protocol Layer (UP) Functions: PDCP carrier mapping (EPS carrier -> radio carrier), Sequence numbering, Header compression, Security, RLC routing, Sequence numbering, Segmentation, ARQ concatenation, MAC programming, HARQ multiplexing.

[00068] In LTE, the RLC layer performs concatenation / segmentation of PDCP PDUs.

[00069] When the transmitter knows the transport block size (TB), the MAC layer performs Logical Channel Prioritization (LCP) to determine how much data each RLC entity should transmit (provide to the lower layers, i.e., to the MAC / PHY). Each RLC entity provides an RLC PDU that contains one or more RLC SDUs. For each RLC SDU that terminates in the RLC PDU, Petition 870240080006, dated 09 / 19 / 2024, p. 33 / 139 27 / 121 A corresponding L field (length field) is added, allowing the receiver to extract the corresponding SDUs. If the last contained RLC SDU does not fit entirely within the RLC PDU, it is segmented, meaning the remainder of the RLC SDU will be sent in the subsequent RLC PDU(s). Whether the first (last) byte of the RLC PDU matches the first (last) byte of the RLC SDU is indicated by the Framing Information flags (2 bits) located in the RLC header. Aside from this, segmentation does not cause excessive additional processing. In order to restore the original data order and detect losses, the RLC sequence number (SN) is added to the RLC PDU header.

[00070] The MAC multiplexes the RLC PDUs for different Logical Channel Identifiers (LCIDs) and adds a corresponding subheader with the LCID and L field. A high-level illustration of the transport block structure is shown in Figure 4. Recently, 3GPP began studying and working on the 5th generation system under the name New Radio (NR). NR aims for very high data rates (currently up to 20 Gbit / s downlink and 10 Gbit / s uplink). LIST OF QUOTES Non-Patent Literature

[00071] NPL 1: 3GPP TS 36.211, Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)

[00072] NPL 2: 3GPP TS 36.321, version 13.3.0

[00073] NPL 3: 3GPP TS 36.213, version 13.0.0

[00074] NPL 4: 3GPP TS 36.322, version 13.2.0

[00075] NPL 5: 3GPP TS 36.212, version 13.0.0 SUMMARY

[00076] As NR is targeting very high data rates, the processing time available to both transmitter and Petition 870240080006, dated 09 / 19 / 2024, page 34 / 139 28 / 121 receiver capacity could be very limited compared to the amount of data to be transmitted. One example to minimize transmitter processing time is to minimize the real-time processing required. For example, in LTE, a PDCP PDU can be generated once a PDCP SDU (i.e., an IP packet) is available; that is, PDCP PDU generation can be done in a non-real-time mode, i.e., regardless of whether or not there are currently resources allocated to the PDCP PDU. However, RLC and MAC PDUs can only be generated in real-time mode (i.e., after receiving the UL grant). Segmentation, concatenation, and multiplexing are required for DL / UL data SDUs to fit within the total TB size allocated by the scheduler.Concatenation and segmentation require knowledge of scheduling / grant size decisions before they can be executed, thus they are subject to strict real-time processing requirements. This also implies that the transmitter cannot perform any pre-processing for either the RLC or the MAC layer, for example, of subheaders / headers before scheduling / grant information. The inability to perform pre-processing incurs a processing delay upon grant reception. If RLC processing and a certain degree of MAC processing could be completed in advance (upon grant reception), then the delay in submitting MAC TB to the PHY layer would be comparatively much smaller.

[00077] Furthermore, the MAC PDU format used in LTE does not allow for early encoding to begin before TB generation has been completed. In LTE, MAC PDU is an iterative process since the size of the control information (header) depends, for example, on the number of SDUs in that PDU. This iterative process Petition 870240080006, dated 09 / 19 / 2024, page 35 / 139 29 / 121 takes time before MAC PDU transmission can begin. Since MAC control elements (MAC CEs, i.e., BSR, PHR) are added at the beginning of the MAC PDU (TB), they need to be computed before the MAC PDU transmission to the PHY can begin. BSR computation can only be done based on the LCP result, while PHR calculation depends on inserting this value into MAC. Therefore, MAC header pre-computation is not possible, and MAC PDUs cannot be transferred to the PHY until the complete MAC PDU is built. Thus, if MAC control elements are placed before any MAC SDU, as in LTE, the MAC layer can only provide available MAC SDUs to the PHY after the MAC control elements have been computed. For example, BSR computation can only be done after LCP has been completed.Also, the power tolerance calculation can take some time and is dependent on PHY signals, for example, the information on whether PUCCH is transmitted or not.

[00078] In view of the above observations, the objective of this description is to provide a proposal that improves the efficiency of layer processing.

[00079] This is achieved by the features of the present invention.

[00080] Advantageous modalities are the subject of the embodiments.

[00081] According to one aspect of the description, a data transmission node is provided to transmit data over a wireless channel to a data reception node in a communication system, which comprises: a second-layer processing circuit to receive, from a third layer, at least one second-layer service data unit, SDU, to be mapped onto a resource allocated for data transmission, and to generate a second-layer protocol data unit, Petition 870240080006, dated 09 / 19 / 2024, page 36 / 139 30 / 121 PDU, which includes said at least one second-layer SDU and at least one second-layer control element, the at least one second-layer control element placed after any of the at least one second-layer SDU, a first-layer processing circuit to receive the second-layer PDU generated by the second-layer processing circuit and map the second-layer PDU over the resource allocated for data transmission.

[00082] According to another aspect, a data receiving node for receiving data over a wireless channel from a data transmitting node in a communication system is provided, comprising: a first-layer processing circuit for unmapping at least one second-layer protocol data unit, PDU, from a resource allocated for data reception, a second-layer processing circuit for receiving and parsing the second-layer PDU unmapped by the first-layer processing circuit, the second-layer PDU including at least one second-layer service data unit, SDU, and at least one second-layer control element, the at least one second-layer control element following any of the at least one second-layer SDU.

[00083] According to yet another aspect of the description, a method is provided for transmitting data over a wireless channel to a data receiving node in a communication system, comprising: receiving, from a third layer, at least one second-layer service data unit, SDU, to be mapped onto a resource allocated for data transmission, generating a second-layer protocol data unit, PDU, which includes said at least one second-layer SDU and at least one second-layer control element, the at least. Petition 870240080006, dated 09 / 19 / 2024, page 37 / 139 31 / 121 a second-layer control element placed after any of at least one second-layer SDU, receives the second-layer PDU generated by second-layer processing and maps the second-layer PDU over the resource allocated for data transmission.

[00084] In a further aspect, a method is described for receiving data over a wireless channel from a data transmission node in a communication system, comprising: unmapping at least one second-layer protocol data unit, PDU, from a resource allocated for data reception, receiving and parsing the unmapped second-layer PDU by the first-layer processing circuit, the second-layer PDU including at least one second-layer service data unit, SDU, and at least one second-layer control element, or at least one second-layer control element following any of the at least one second-layer SDU.

[00085] Furthermore, a computer-readable means is provided for storing instructions thereon, which when executed on a computer, cause the computer to execute the steps of the above methods. BRIEF DESCRIPTION OF THE DRAWINGS

[00086] The following exemplary embodiments are described in more detail with reference to the attached figures and drawings.

[00087] Figure 1 shows an exemplary architecture of a 3GPP LTE system.

[00088] Figure 2 shows an exemplary overview of the overall 3GPP LTE E-UTRAN architecture.

[00089] Figure 3A illustrates the OSI model with the different layers for communication.

[00090] Figure 3B illustrates the relationship of a data unit of Petition 870240080006, dated 09 / 19 / 2024, page 38 / 139 32 / 121 protocol (PDU) and a service data unit (SDU) as well as the interlayer exchange between them.

[00091] Figure 4 provides an overview of the different functions in the PDCP, RLC and MAC layers, as well as exemplarily illustrating the processing of SDUs / PDUs by the various layers.

[00092] Figure 5A is a schematic drawing illustrating data processing by different layers of the radio access network in the LTE user plane.

[00093] Figure 5B is a schematic drawing that illustrates the preprocessing of MAC-PDUs and their mapping over physical resources by modifying the preprocessed headers.

[00094] Figure 6 is a schematic drawing of an exemplary three-layer transmission-side processing.

[00095] Figure 7 is a schematic drawing of an exemplary receive-side processing by the three layers in the case of one of the two MAC PDUs being lost.

[00096] Figure 8 is a schematic drawing of exemplary transmission-side processing by the three layers in the event that one of the two MAC PDUs is lost.

[00097] Figure 9 is a schematic drawing of an exemplary receive-side processing by the three layers in the case where both MAC PDUs are received correctly.

[00098] Figure 10 is a schematic drawing showing exemplary layer processing on the transmitter side for a first transmission.

[00099] Figure 11A is a schematic drawing illustrating the structure of an LTE status report. [000100] Figure 11B is a schematic drawing illustrating the structure of an RLC status report. Petition 870240080006, dated 09 / 19 / 2024, page 39 / 139 33 / 121 [000101] Figure 12 is a schematic drawing showing exemplary layer processing on the transmitter side for a first transmission using segment numbers. [000102] Figure 13 is a schematic drawing showing exemplary layer processing on the receiver side for the first transmission using segment numbers. [000103] Figure 14 is a schematic drawing showing an exemplary layer processing on the transmitter side for a retransmission using (re)segment numbers. [000104] Figure 15 is a schematic drawing showing an exemplary layer processing on the receiver side for retransmission using (re)segment numbers. [000105] Figure 16 is a schematic drawing showing an exemplary layer processing on the transmitter side for a first transmission supporting multiple connections. [000106] Figure 17 is a schematic drawing showing an exemplary layer processing on the receiver side for the first transmission supporting multiple connections. [000107] Figure 18 is a schematic drawing showing an exemplary layer processing on the transmitter side for a retransmission that supports multiple connections. [000108] Figure 19 is a schematic drawing showing an exemplary layer processing on the receiver side for retransmission supporting multiple connections. [000109] Figure 20 is a block diagram illustrating a functional structure of exemplary data transmission and reception devices. [000110] Figure 21 is a flowchart that illustrates exemplary method steps executed on the transmission and reception sides. [000111] Figure 22 is a schematic drawing showing a Petition 870240080006, dated 09 / 19 / 2024, page 40 / 139 34 / 121 exemplary structure of the user plan protocol stack for NR. [000112] Figure 23 is a schematic drawing showing an exemplary MAC PDU format. [000113] Figure 24 is a schematic drawing of a MAC PDU format that includes MAC control elements following MAC SDUs. [000114] Figure 25 is a schematic drawing showing another exemplary MAC PDU format and an exemplary MAC subheader structure. [000115] Figure 26 is a schematic drawing showing an exemplary MAC PDU format including a Temporary Storage Status Report MAC control element. [000116] Figure 27 is a schematic drawing showing an exemplary MAC PDU format that includes an Enable / Disable MAC control element. [000117] Figure 28 is a schematic drawing showing an exemplary MAC PDU format for processing in both directions. [000118] Figure 29 is a schematic drawing showing the MAC PDU format of Figure 28 and MAC subheaders that include flags which indicate the presence of MAC control elements and additional MAC subheaders. [000119] Figure 30 is a schematic drawing that shows yet another exemplary MAC PDU format. [000120] Figure 31 is a schematic drawing of a data transmission node and a data reception node. [000121] Figure 32 is a flowchart that illustrates a method for transmitting data and a method for receiving data. [000122] Figure 33 is a schematic drawing showing a Petition 870240080006, dated 09 / 19 / 2024, page 41 / 139 35 / 121 exemplary PDU format that includes MAC control elements at the beginning and end. DESCRIPTION OF MODALITIES [000123] A mobile station or mobile node or user terminal or user equipment (UE) is a physical entity within a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that implements and / or offers a predetermined set of functions to other functional entities of a node or the network. Nodes may have one or more interfaces that attach the node to a communication facility or medium over which the nodes can communicate. Similarly, a network entity may have a logical interface that attaches the functional entity to a communication facility or medium over which it can communicate with other functional entities or corresponding nodes. [000124] The terms radio resources as used in the embodiments should be broadly understood as referring to physical radio resources, such as time-frequency radio resources. [000125] The following exemplary embodiments provide an enhanced radio interface layer processing for the new radio technology anticipated for 5G mobile communication systems. Up to now, very few details have been agreed upon regarding the 5G mobile communication system, so many assumptions need to be made below in order to explain the principles underlying the embodiments. These assumptions should, however, be understood as merely examples that should not limit the scope of the description. A person skilled in the art will be aware that the principles of the present description as Petition 870240080006, dated 09 / 19 / 2024, page 42 / 139 36 / 121 presented in the embodiments can be applied to different scenarios and in modes not explicitly described here. For example, the new radio technology will be developing from the radio technology already defined for LTE (-A), although several changes can be expected in order to meet the requirements for 5G mobile communication systems. Consequently, specific exemplary implementations of the various embodiments could still reuse procedures, messages, functions, etc. already defined for LTE (-A) communication systems (according to Release 10 / 11 / 12 / 13 / 14 etc.) provided that these are equally applicable both to the new radio technology for 5G communication systems and to the various implementations as explained for the following embodiments. [000126] According to the present description, the concatenation / segmentation functionality is moved from the RLC layer to the MAC entity. This proposal provides some advantages, for example, RLC PDUs and partially MAC PDUs can be pre-constructed at the terminal (if the transmission is performed on the uplink), before a UL lease is received. This reduces processing time by pre-constructing the respective RLC PDU and partially MAC PDU. The RLC layer does not need to wait for the MAC scheduling decision and the RLC PDU size indication (both burdened with resource allocation by L1 / L2 signaling). This reduces processing time in transport block generation. [000127] Figure 5A shows the main protocol layer functions on the transmitter (TX) and receiver (RX) sides. As can be seen, on the transmitter side, segmentation is performed at the MAC layer, in cooperation with the RLC layer. [000128] Figure 5B illustrates a basic operation performed on the side Petition 870240080006, dated 09 / 19 / 2024, page 43 / 139 37 / 121 transmitter: a) The RLC and / or MAC PDUs are pre-processed on a PDCP PDU basis, i.e., the RLC layer does not concatenate the PDCP PDUs. However, the RLC layer can additionally segment the RLC SDU (PDCP PDU), which is illustrated by two results of a PDCP PDU segmentation, namely R1-PDU1 and R2-PDU2. The pre-processing could be based on a minimum (or alternatively, an average) grant size which is statistically available, with a certain high level of confidence, under a given radio condition (e.g., RSSI / RSRP, etc.). Thus, a pseudo LCP (since this works with estimated grant sizes) is run on its minimum or average grant size, and the RLC and MAC PDUs are pre-processed accordingly.When the (actual) grant is received and the LCP has been executed at the MAC layer, some of the pre-processed RLC PDUs, which can be accommodated in the granted resources (i.e., the size of the corresponding MAC PDU is less than or equal to the grant size for the corresponding LCID) based on the LCP result, will be submitted to the physical layer. The physical layer can start processing these immediately, i.e., at time instance t1. In Figure 5B, the pre-segmented R1-PDU1 and R2-PDU2, which have the pre-processed MAC header attached, can be accommodated in the granted resources. b) The pre-segmented R1-PDU2 and R2-PDU2 cannot be accommodated as a whole within the granted resources; therefore, further segmentation of these PDUs is required, knowing the allocation size and after the LCP has been executed. In other words, the remaining grant (after the above step) would require that the pre-processed PDUs be segmented and their headers... Petition 870240080006, dated 09 / 19 / 2024, page 44 / 139 38 / 121 corresponding data points need to be recomputed. Segmentation can be done at the MAC layer (on the RLC PDUs which have already been pre-processed and submitted to it) or at the RLC layer (RLC recomputing the header after segmentation based on the LCP result). After this L2 processing, the resulting part(s) (segments) of the MAC PDU are submitted to the physical layer. The physical layer can then begin its processing on these subsequently (i.e., at time instance t2). [000129] In Figure 5B, the two different RLC entities belong to different logical channels. Consequently, the MAC also decides, based on the Logical Channel Prioritization (LCP) procedure, which of the corresponding MAC PDUs should be provided to the physical layer at which point in time. An example of an LCP procedure is known from LTE and referred to above in the background section. Nevertheless, the present description is not limited to this and in general. [000130] On the receiver side, after physical layer processing, the corresponding reverse steps are performed: a) The MAC layer performs demultiplexing based on the MAC header (basically the LCID field and the Length field) and provides the resulting MAC SDU(s) to the RLC. When the MAC layer passes the MAC SDU to the RLC layer, the latter also retains the segmentation / concatenation header field since segmentation and concatenation are done by the MAC and segment reordering and reassembly are performed by the RLC. This is why the MAC passes the archived segmentation header to the RLC. In other words, the MAC layer passes to the RLC not only the MAC SDU, but also part of the MAC header related to segmentation / concatenation. b) The RLC layer reassembles the RLC PDU segments. Petition 870240080006, dated 09 / 19 / 2024, page 45 / 139 39 / 121 (if applicable) before transferring the complete RLC SDU(s) to PDCP. The submission of complete RLC SDUs to PDCP is also done out of order, i.e., including gaps where a segment is missing, for example, because it was not correctly received within a predefined time or a predefined number of retransmissions. However, the RLC needs to track the PDUs and the missing PDU segment(s). ARQ runs on RLC, so any missing RLC PDU segment and / or PDU segment must be reported to the TX side for possible retransmission. Here, ARQ must attempt to recover the missing RLC PDU and / or PDU segment until a timer, Timer1, expires. Timer1 is initiated when a gap first appears (or when the subsequent / next RLC SDU is provided to the PDCP layer). When Timer1 expires, the RLC should inform the PDCP layer as well as the RRC.The RRC could take additional actions such as triggering a Radio Connection Failure (RLF) procedure. In general, higher-layer end-to-end protocols, such as TCP, can still handle proper provisioning. c) The PDCP layer must decrypt incoming PDUs received from the RLC based on PDCP SN (or COUNT, if available directly from the header; otherwise, it needs to estimate / calculate COUNT from the SN included in the PDCP header). The COUNT calculation will be done by adjusting the last COUNT value with the difference between the last PDCP SN and the PDCP SN value in the received PDCP PDU header. Here, "last" refers to the previous PDCP PDU that was successfully decrypted. Additionally, the PDCP must wait for the hole(s) to arrive from the RLC. However, if the RLC indication (when Timer1 expires) arrives before the corresponding PDCP PDU is received, the PDCP SDUs are submitted to... Petition 870240080006, dated 09 / 19 / 2024, page 46 / 139 40 / 121 top layers (including holes). [000131] The above proposal is applicable not only to AM, but also to UM. In the case where UM is applied, there are no retransmissions over the RLC layer. Nevertheless, on the receiver side, if an RLC PDU or a segment RLC PDU is missing, the RLC SDU will still be provided for the PDCP layer. [000132] In AM, when the RLC Status Report indicates that an RLC PDU and / or PDU segment is missing, the TX-side RLC submits the missing RLC PDU and / or corresponding PDU segment to the MAC layer, including a suitable header to assist the receiver in reassembling the segment(s) by retransmitting it. [000133] Alternatively, the RLC layer can submit the entire RLC PDU to the MAC layer, even if only a segment of the corresponding RLC PDU was indicated as missing; furthermore, the RLC layer shares the Status Report details (i.e., the entire status report) with the MAC layer. An advantage of this proposal is to reduce the RLC header over-processing. If resegmentation is done in the RLC layer, then the RLC layer adds segmentation header fields which increase the header over-processing. To overcome this problem, the complete RLC PDU is sent to MAC and MAC performs segmentation based on the status report. The RLC status report is understood by MAC since a universal (common) sequence number is being used between the layers (PDCP, RLC, MAC).In this case, the MAC layer performs re-segmentation based on this knowledge and the LCP result, and includes an appropriate header to assist the receiver in reassembling the segment(s). [000134] Note that the description above refers to MAC, RLC Petition 870240080006, dated 09 / 19 / 2024, p. 47 / 139 41 / 121 and PDCP, which are terms used in the UMTS / LTE (-A) standards. However, this description is not limited to these standards or their advancements and may function independently of the terminology used. [000135] In other words, the structure can be seen as a protocol stack in which there is a first layer responsible for mapping / unmapping data onto / from physical resources (corresponding to the physical layer), a second layer (corresponding to MAC), and a third layer (corresponding to RLC and / or PDCP). It is noted that the terms first layer, second layer, and third layer here do not necessarily correspond to the OSI model layers. [000136] Protocol stack processing latency reduction can be achieved on a transmitter side with a first physical layer; a second layer; and a third layer where the second layer receives pre-processed third-layer PDUs (generated by the third layer without knowledge of resource allocation) from the third layer and receives (from the receiver in uplink or internally in downlink) resource allocation for the physical layer. The pre-processed third-layer PDUs can be appended (either in the third layer or the second layer) with a header that includes segmentation information. It is noted that such pre-processed third-layer PDUs can be provided for a plurality of third-layer entities, which corresponds to a plurality of logical channels which may have different priorities. Consequently, the second layer can then execute a prioritization procedure.Based on the resource allocation received and possibly also on the result of the prioritization procedure, the second layer then provides the first layer with the pre-processed third-layer PDUs. Petition 870240080006, dated 09 / 19 / 2024, page 48 / 139 42 / 121 suitable including segmentation information as the second-layer header at a first point in time t1 and possibly performs additional segmentation of the preprocessed PDUs and modifies the segmentation information in the header consequently before providing the data to the first layer at a point in time t2 subsequent to point in time t1. [000137] It is noted that third-tier PDUs received in the second tier can already be pre-segmented according to the ARQ status report if the third tier implements ARQ. But this proposal is also applicable if the third tier does not implement ARQ. Pre-segmentation can then be done based on some statistical measures of past allocations or according to another rule, or it may not need to be performed at all. [000138] Furthermore, the present description can also be advantageously applied to dual or multiple connectivity. Multiple Connectivity is a mode of operation whereby a multiple Rx / Tx UE in connected mode is configured to utilize radio resources between E-UTRA and NR provided by multiple distinct programmers connected via a non-ideal backhaul. In other words, with multiple connectivity, a layer above the third layer in the transmitter (such as a terminal) provides the same packet (IP or PDCP) to be transmitted to multiple base stations (eNBs). The two or more base stations then receive the same packet independently, thus increasing the probability of correct reception by the network. [000139] The concept of multiple connectivity is somewhat similar to dual connectivity, which is a promising solution under discussion in 3GPP RAN working groups. Dual connectivity is the concept thus termed. The term dual connectivity is used to refer to an operation where a given UE consumes radio resources. Petition 870240080006, dated 09 / 19 / 2024, page 49 / 139 43 / 121 provided by at least two different network nodes connected with a non-ideal backhaul. Essentially, a UE is connected to both a macro cell (macro eNB) and a small cell (secondary eNB). Furthermore, each eNB involved in dual connectivity for a UE can assume different roles. These roles do not necessarily depend on the eNB's power class and can vary between UEs. However, unlike dual connectivity, where different data is sent from one UE to different eNBs, in multiple connectivity, the same IP / PDCP packet is transmitted over a plurality of connections / cells. Among the multiple receiving eNBs, one is acting as the master eNB, which implements the layer that performs the reassembly of received segments across multiple connections. The master eNB communicates with the other eNBs. [000140] For example, speaking in terms of LTE, the PDCP layer takes on the reassembly function in addition to other functions it already performs when switching from single to multiple connectivity. The ARQ can also run at the RLC layer (in AM), and in this case, the PDCP layer will need to share the details of missing PDCP SNs (totally or partially) with the RLC layer. The PDCP layer will inform the RLC layer about the missing segments. Subsequently, the RLC layer receiving entity will send a status report to the RLC layer transmitting entity. Therefore, a separate ARQ at the RLC and PDCP layers is not required, meaning that for both single and multiple connectivity, the ARQ can both run at the RLC layer. Alternatively, the PDCP layer can compose its own Status Report and send it to the TX-PDCP entity. The Status Report should contain information about the missing PDCP PDUs and / or PDUs. Petition 870240080006, dated 09 / 19 / 2024, page 50 / 139 44 / 121 [000141] In order to allow for latency reduction and / or reduction of over-processing as described above, this description provides an efficient layer model to be implemented on the transmitter and receiver sides. This includes one or more of the following: - Move the segmentation to the second layer, that is, as close as possible to the physical layer which must perform the real-time processing, since this maps the data over the physical resources (of the third layer). This provides the possibility of preparing the data for transmission over a shared channel even before the corresponding lease is received. (The terminal implementation may or may not make use of this possibility. In other words, whether or not the terminal time makes use of pre-processed PDUs can be left to the implementation). - Employ common control information accessed by multiple layers. Usually, the layer model assumes that each layer only accesses the control information generated on that layer: This sometimes leads to the overlapping of duplicate control information being provided in different layers, i.e., PDU headers from different layers. This can be the case for the sequence number, which allows reordering of received data. A common sequence number can be used for more than one layer (such as PDCP and RLC), which reduces excessive header processing. - A higher layer (such as the third layer or more specifically RLC or PDCP) supports ARQ functionality. Therefore, based on the third layer's status report, the third layer performs PDU segmentation. Here it is assumed that the third layer's PDU segmentation based on the status report may differ from the segmentation performed based on the received allocation executed in the lower layer (second layer or Petition 870240080006, dated 09 / 19 / 2024, page 51 / 139 45 / 121 more specifically MAC). A similar advantage can be achieved if the third layer provides the second layer with segmentation information based on the status report, and only the second layer performs segmentation based on both allocation and status report. This approach saves both time (thanks to pre-processing) and resources (resegmentation only allows retransmission of missing segments). Layer 2 Segmentation, Layer 3 Pre-Segmentation for ARQ [000142] According to one embodiment, a data transmission node is provided to transmit data over a wireless interface in a communication system to a data reception node. In order to implement the protocol stack layer model functionality, the data transmission node comprises a third-layer processing unit (hereinafter a processing unit may be replaced by a processing circuit) to perform or not a retransmission of ARQ according to a status report fed back from the data reception node and to resegment or not the data to be retransmitted (if any) based on the segment length information included in the status report. Resegmentation includes adding segmentation control information to the segmented data, for example, as a header.This header is also advantageously interpreted and used in a second layer, provided to the second layer along with the third-layer data unit. In this embodiment, it is assumed that the retransmission protocol is handled by the third layer, which does not exclude the application of independent ARQ / HARQ protocols in other layers. Petition 870240080006, dated 09 / 19 / 2024, p. 52 / 139 46 / 121 layers below or above the third layer. [000143] The data transmission node further comprises a second-layer processing unit to receive, from the third-layer processing unit, a third-layer data unit, segment the third-layer data unit based on a resource allocation, and form a plurality of second-layer data units that include the respective segments of the third-layer data unit and the segmentation control information, which is modified if resegmentation is to be applied. The resource allocation may be either received from the data reception node or generated in the data transmission node. For example, if the transmission node is a terminal (UE), the resource allocation (uplink grant) may be received from a base station, i.e., the data reception node. On the other hand, if the transmission node is a base station, the resource allocation for transmission may be generated in the base station and provided to the MAC layer.However, this description also applies to direct communication between terminals, or between transfer stations and terminals, or between transfer stations and base stations. [000144] Finally, the data transmission node comprises a first-layer processing unit to receive from the second layer one or more of the plurality of second-layer data units and map the one or more of the plurality of second-layer data units over the resources allocated for data transmission. [000145] It is noted that the data transmission node may also include a fourth-layer processing unit to provide a sequence number within its header. The sequence number is incremented for each new fourth-layer SDU, i.e., with each IP packet; the increment may be cyclical while the Petition 870240080006, dated 09 / 19 / 2024, page 53 / 139 The 47 / 121 sequence number has a predefined maximum value. Advantageously, the third layer does not provide another sequence number, but encapsulates the fourth-layer processing unit, including the sequence number via the PDCP layer. [000146] In LTE terminology, the first layer can be the physical layer, the second layer can be the MAC layer, and the third layer can be the RLC layer, while the fourth layer can be PDCP. However, it is noted that the third layer can also be considered to be the PDCP layer in some modes or a combined layer with functions of both RLC and PDCP, especially in the case of architectures that evolve based on the present LTE. [000147] Figure 6 illustrates processing on a transmitter side according to this modality and exemplified using LTE terminology. The transmitter side can be the terminal that transmits data in the uplink to a base station. However, the present description is not limited to this, and the transmit side can be a terminal that transmits data to another terminal or to any other node. Furthermore, the present description can also be applied to a base station or a transfer node or another node being the data transmitter. [000148] As shown in Figure 6, an IP packet 1 with a length of 1200 bytes is provided to the PDCP layer, thus forming a PDCP SDU. The PDCP SDU is added to a header that includes a D / C indicator which can be a single bit. This bit indicates whether the content of the PDCP PDU is a Data or Control PDU. In this example, this is set (i.e., the bit is equal to 1) for a data PDU and not set (i.e., the bit is equal to 0) for a control PDU. However, in general, the set / not set can be reversed. The PDCP header also includes the sequence number. Petition 870240080006, dated 09 / 19 / 2024, page 54 / 139 48 / 121 of PDCP (SN). [000149] A PDCP PDU1 (with a payload of 1200 bytes) is sent to the RLC layer, thus forming an RLC SDU. The RLC layer includes the RLC header relevant to the RLC PDU. As can be seen in the figure, the RLC header includes another D / C flag, a P flag, and an RF flag. The D / C flag indicates whether control or data is carried by the RLC PDU, while the P flag is a query bit which is set to request a status report from the receiver (point RLC entity). If it is not set, then a status report is not requested. The RF flag is a resegmentation flag that indicates whether the RLC PDU is a complete PDCP PDU or a segment of a PDCP PDU. The RF value is initially set to 0, indicating that the RLC PDU is a complete PDU and then provided to the MAC layer as part of RLC PDU1.In this example, for the first data transmission of the PDCP PDU / IP packet, the RLC layer does not perform segmentation; instead, the MAC layer performs segmentation. Consequently, for the first transmission, the RF value is always set to 0. [000150] In the example in Figure 6, the transmitter MAC entity needs to segment the RLC PDU based on the received lease. Furthermore, the lease sizes assumed in this example are 800 and 400 bytes on two different transmission occasions (or at least one lease for 800 bytes and the remainder awaiting another lease). Thus, the MAC layer segments the RLC PDU that corresponds to a MAC SDU. After segmenting the RLC PDU, the transmitter MAC entity includes relevant segmentation MAC header portions within the respective MAC PDUs to indicate a segment offset (SO) and last segment field (LSF) of the included RLC PDU and forms the MAC PDUs which Petition 870240080006, dated 09 / 19 / 2024, p. 55 / 139 49 / 121 are referred to as MAC PDU1 and MAC PDU2 in Figure 6. MAC PDU1 contains an 800-byte payload while MAC PDU2 contains a 400-byte payload. MAC PDU1 and MAC PDU2 are sent to TTI0 and TTI1, respectively. TTI0 and TTI1 are then multiplexed onto different resources, for example, different time resources. However, it is noted that this is not to limit the present description to the mapping of the two MAC PDUs to different points in time. More than one MAC PDU can generally be mapped onto different types of resources, for example, different frequencies or different streams of a MIMO system, orthogonal codes, or similar. [000151] The SO field in this example indicates the PDU segment position in bytes within the original PDU. Specifically, the SO field indicates the position within the original PDU's data field to which the first byte of the PDU segment data field corresponds. The first byte in the original PDU's data field is referenced by the SO field value of zero. The LSF field indicates whether or not the last byte of the PDU segment corresponds to the last byte of a PDU. [000152] The MAC layer may include additional fields within MAC PDU1 and MAC PDU2, such as a Logical Channel ID (LCID) and an extension flag (E), which indicates whether or not there are other fields after the MAC header. The value 1 indicates that there are at least one or more E / LCID fields following this field. The value 0 indicates that there are no more E / LCID fields following this field, implying that the next byte is an initial byte of the MAC SDU. There may be additional fields or reserved fields in the header (not shown in the Figure). [000153] According to this modality, a data receiving node is also provided to receive data about a Petition 870240080006, dated 09 / 19 / 2024, p. 56 / 139 A 50 / 121 wireless interface in a data transmission node communication system. The data reception node comprises a first-layer processing unit for unmapping one or more of a plurality of second-layer data units from the resources allocated for data transmission and for providing one or more of the plurality of unmapped second-layer data units to the second-layer processing unit. Furthermore, the data reception node also comprises a second-layer processing unit for performing demultiplexing of a plurality of third-layer unit segments and segmentation control information from one or more of the plurality of second-layer data units, and transferring the plurality of demultiplexed third-layer unit segments along with the segmentation control information to a third-layer processing unit.The data receiving node still comprises the third-layer processing unit to perform the reordering of the plurality of demultiplexed third-layer segments and assembly into a third-layer unit. [000154] Thus, the segmentation information which is part of the second-layer data units (and can be specifically loaded in the second-layer header) is also observed and used in the third layer. This proposal therefore disregards the strict separation of layers on the one hand; on the other hand, it saves processing overhead and allows efficient reordering and reassembly in the third layer. This is particularly advantageous if the ARQ procedure is implemented in the third layer, which – however – is not necessary and not limiting for the present description. Petition 870240080006, dated 09 / 19 / 2024, page 57 / 139 51 / 121 [000155] According to an exemplary implementation, the third-layer processing unit in the data receiving device is further configured to generate control data that carries a status report indicating whether or not at least one third-layer unit segment was correctly received. The status report may include at least one positive acknowledgment or negative acknowledgment for at least one third-layer data unit and / or identification of correctly received or missing segments of the third-layer data unit. An exemplary format of the status report which may be employed here can be found in 3GPP TS 36.322, Version 13.2.0, Section 6.2.1.6. However, it is noted that this is only an example and the status report may have a different format and content provided that it allows a positive and / or negative acknowledgment of receipt for a third-layer PDU or its segments. [000156] Figure 7 illustrates an exemplary reception processing of MAC PDU1 and MAC PDU2 received over an error-prone channel. As shown in Figure 7, MAC PDU1 is received (800 bytes of payload) correctly but MAC PDU2 (400 bytes of payload) is lost (cannot be correctly decoded, i.e., the CRC failed). [000157] The MAC layer performs demultiplexing of RLC PDU1 and sends it to the RLC layer. The RLC layer then performs reassembly and reordering of the MAC segments. The RLC receiving side (RX) sends a status report indicating correct reception of the 800 to 1200 bytes belonging to MAC PDU1 to the RLC transmitting side (TX). The reordering and reassembly of the RLC PDU segments is performed based on the header information from the MAC layer. This includes the example Petition 870240080006, dated 09 / 19 / 2024, page 58 / 139 52 / 121 of Figure 7 specifically the segment displacement and the LSF indicator. The RLC layer D / C field allows distinguishing between RLC data PDUs and RLC control PDUs such as status reports. [000158] Figure 8 shows exemplary subsequent actions on the RLC transmission side, assuming the transmitting side is aware of the missing second MAC-PDU2 segment (e.g., based on the status report). As shown in Figure 8, in this example the RLC TX takes the complete RLC PDU of the corresponding missing packet from the temporary transmission store and performs a new segmentation (resegmentation) of the 400 (800 to 1200) bytes which are indicated in the RLC status report as missing. The resegmentation also includes attaching the appropriate RLC header. The RLC header here includes the segment offset which indicates the position of the RLC PDU segment which should be retransmitted via an offset in bytes. In this example, the segmentation offset SO = 801, since the missing 400 bytes from 801 to 1200 should be retransmitted. Then the resegmented RLC PDU that corresponds to the missing 400 bytes is provided to the MAC layer. [000159] The MAC layer then performs segmentation of the received RLC PDU and forms MAC PDU1 (which contains 200 bytes of data) and MAC PDU2 (which also contains 200 bytes of data), which are then sent to TTI0 and TTI1 respectively – as described above with reference to Figure 6 for the first transmission. Of course, in general, the MAC layer only performs segmentation if it is required. Here in this example, the lease size is not sufficient, and this is why the MAC layer forms MAC PDU1 and MAC PDU2. If the allocation is sufficient, no segmentation is required, or possibly, concatenation is performed (in the case of Petition 870240080006, dated 09 / 19 / 2024, p. 59 / 139 53 / 121 allocation being greater than that required for a MAC PDU). [000160] Specifically, the MAC layer reads the SO field and the LSF field from the RLC header and modifies them based on the lease size, i.e., in this example to reflect the segmentation size of 200 bytes and 200 bytes, respectively. As can be seen in Figure 8, the MAC layer provides the new segmentation information in the respective headers of the segmented MAC PDUs, namely, SO = 801 and SO = 1001, which correspond to the position of the new data segments to be retransmitted within the first transmitted (unre-segmented) RLC PDU and the LSF. Figure 9 illustrates an example in which MAC PDU1 and MAC PDU2 from Figure 8 are both correctly received. The MAC layer provides the correctly received MAC PDU1 and MAC PDU2 to the RLC layer. The RLC layer performs the reordering and reassembly of the MAC segments and then provides the complete PDCP PDU to the PDCP layer. Reordering is performed based on sequence numbers (SN).As mentioned above, a single sequence number is advantageously used for both the PDCP and RLC layers, in order to save on excess processing. [000161] In other words, the RLC RX collects all segments of the RLC PDU (retransmitted or correctly received after the first transmission), reorders them based on MAC header information, and reassembles the RLC PDU. The reassembled PDU can then be provided to higher layers (such as PDCP or directly IP if PDCP does not exist) for further processing. [000162] Consequently, the present description modifies the functions performed by the different layers of the RAN protocol stack as illustrated below in Table 2. Petition 870240080006, dated 09 / 19 / 2024, page 60 / 139 54 / 121 Table 2 Table 2: NR protocol stack tasks PDCP Protocol Layer Functions: PDCP TX - Header compression - Attached SN - Encoding - Retransmission RLC TX - Provide packets to MAC layer - (Re)segmentation in packet retransmission MAC TX - Concatenation / multiplexing - Segmentation - HARQ transmission MAC RX - HARQ reception - RLC demultiplexing RX - MAC segment reordering / status reporting (Retransmission) - Packet reassembly - Out-of-sequence provisioning to PDCP PDCP RX - Packet decryption - Reordering / status reporting based on full PDU - Header decompression [000163] The following Tables 3-5 provide examples of headers for the respective PDCP, RLC, and MAC layers. Table 3 Table 3: Description of the PDCP header fields Data / Control Bit (D / C) D / C indicates whether the PDU is a data or control PDU. Sequence Number 10-bit sequence number Petition 870240080006, dated 09 / 19 / 2024, page 61 / 139 55 / 121 (SN) Table 4 Table 4: Description of the RLC header fields Data / Control Bit (D / C) D / C indicates whether the PDU is a data or control PDU. Resegmentation Flag (RF) RF indicates whether the PDU is a full or segment PDU. Query Bit (P) The P field indicates whether or not the transmit side of an AM RLC entity requests a STATUS report from its peer. Table 5 Table 5: Description of MAC header fields Length Indicator (LI) The LI field indicates the length in bytes of the corresponding Data field element present in the MAC data PDU provided / received by the MAC entity. Extension Bit (E) The E field indicates whether this field is the end of the header or if another extension follows. Segment Offset (SO) The SO field indicates the starting position of the first byte of the corresponding MAC SDU in bytes. Last Segment Field (LSF) The LSF is set to 1 to indicate that this is the last segment of the RLC PDU. [000164] In the tables above, the sequence number length is exemplified as 10 bits. However, it is noted that this is only an example which should not limit the present description. In LTE, the PDCP sequence number length can be Petition 870240080006, dated 09 / 19 / 2024, page 62 / 139 56 / 121 bits, 7 bits, or 12 bits depending on the characteristics of the radio carrier. The length of the sequence number is a matter of system design, as is clear to those skilled in the art; any length can be selected for the purposes of the present description. [000165] As shown in Figure 6, PDCP PDUs are sent to the RLC layer at the receiver. Advantageously, the PDCP, RLC, and MAC layers use a universal sequence number which is understood by all these layers. In this example, the PDCP sequence number is used, which is understood by all three layers, or at least the PDCP and RLC, since the SN is not necessarily needed in the lower layers. [000166] The RLC layer includes a relevant RLC header in the RLC PDU, for example, the RF field to indicate a complete or segmented PDU. The RF value is initially set to 0 and is updated when a status report arrives at the RLC TX. When the transmitting side transmits the RLC data PDUs, it still stores the RLC PDUs in temporary retransmission storage for possible retransmission. A retransmission can be requested by the receiver via the status report. As can be seen in Figure 6, the RLC PDUs are then provided to the MAC layer. Subsequently, the transmitting MAC entity performs segmentation and / or concatenation on the MAC SDU received from the upper layer (RLC) to form the MAC PDU(s). [000167] The size of the MAC PDU in each transmission opportunity (TTI) is decided and notified by the MAC layer itself depending on the radio channel conditions and transmission resources available for this. As mentioned in the history section, dynamic scheduling can be applied to the shared channel so that a different allocation is used in each TTI. Petition 870240080006, dated 09 / 19 / 2024, page 63 / 139 57 / 121 possible (capable of accommodating a different amount of data, for example, due to the variable modulation and encoding scheme for better connection adaptation). [000168] The size of each transmitted MAC PDU can therefore be different. Transmission MAC entities include RLC PDUs / MAC SDUs in a MAC PDU in the order in which they arrive at the MAC entity. Therefore, a single MAC PDU can contain complete RLC PDUs or a segment of an RLC PDU since the MAC can perform not only segmentation but also concatenation, depending on the respective segment sizes and allocated resources. If a MAC PDU contains N (N being an integer greater than 0) RLC PDUs and / or PDU segments, then the MAC layer must include N-1 Length fields (L fields) for all corresponding RLC PDUs and / or PDU segments, that is, one L field for each RLC PDU and / or PDU segment, except for the last one. [000169] On the receiver side, as shown in Figure 7 (the LI fields are not shown since the Example in Figures 6-9 refers to segmentation rather than concatenation), the MAC layer knows where the actual data begins since it knows both the header length and – with the L field – the MAC PDU length. The header length is assumed to be known here. For example, it may be predefined (e.g., specified in a pattern) and / or indicated within a field in the header. In the example above, the extension bit is used to indicate whether the header continues or terminates, which makes it possible to determine the header size. [000170] The MAC layer performs demultiplexing of the MAC PDUs without removing the segmentation fields (SO and LSF), and then the demultiplexed RLC PDUs / segments are provided to the Petition 870240080006, dated 09 / 19 / 2024, page 64 / 139 58 / 121 RLC layer. When the receiving RLC layer receives the RLC PDU segments, it first reorders and reassembles them if they are received out of sequence (as also shown in Figure 9). One of the advantages of not performing reordering and reassembly at the MAC layer is the reduction in processing time. If a segment is missing on the receiving side, then the MAC layer could not perform reassembly and reordering, which would add a delay in delivery to the upper layer (RLC). In order not to delay reassembly and reordering, the MAC layer passes the segmentation fields (SO, LSF) to the RLC layer since segmentation and concatenation are performed by the MAC layer, as described above with reference to Figure 6.Therefore, the RLC layer reads the segmentation header field(s) received from the MAC layer and, based on the segmentation header field(s) (e.g., LSF) and concatenation (e.g., LI), the RLC layer performs, where appropriate, reordering and reassembly. Consequently, cross-layer interaction is required in this example since the receiving RLC layer needs to know and utilize the MAC layer signaling fields. [000171] Any RLC PDUs received out of sequence at the MAC layer are provided to the upper layer (RLC). An ARQ operation is performed on the receiving RLC to support error-free transmission (confirmed mode). In order to allow the transmitting side to retransmit only the missing RLC PDUs, the receiving side provides an RLC status report to the transmitting side indicating the missing PDU(s) or PDU segment(s) information for the RLC PDUs. [000172] In response to a status report with one or more missing PDUs / segments, the RLC layer transmitter takes the Petition 870240080006, dated 09 / 19 / 2024, p. 65 / 139 59 / 121 The RLC completes the corresponding missing packet from the temporary transmission store and performs (re)segmentation based on the missing segment(s) indicated by the RLC status report. If a re-segmentation is performed after receiving the status report, the RLC changes the RF field from 0 to 1. Then the (re)segmented PDU(s) is / are provided to the MAC layer, which reads the RF flag. Because radio conditions can deteriorate during the retransmission procedure, the missing segment PDU(s) may need to be broken down into smaller segments (re-segmented) before retransmission (which is done by the MAC layer). This is illustrated in Figure 8, in which the missing 400-byte payload RLC PDU is taken from the RLC layer of the original 1200-byte payload RLC PDU in temporary retransmission storage and further split (resegmented) into 200-byte payload MAC PDUs. Resegmentation in the MAC layer [000173] When observing Figure 8, it can be seen that the RLC over-processing is slightly increased, since the RLC transmitter performs resegmentation based on the missing segment portion, that is, based on the 400-byte-long data that was not correctly received and which is indicated in the RLC status report and then provided to the MAC layer. Consequently, the resegmentation header (including SO, RF, and LSF) is required in the RLC, which increases the RLC header over-processing. [000174] In order to reduce processing overload, according to one modality, resegmentation is performed at the MAC layer. [000175] Specifically, according to this modality, a node Petition 870240080006, dated 09 / 19 / 2024, p. 66 / 139 A 60 / 121 data transmission node is provided to transmit data over a wireless interface in a communication system to a data receiving node. The data transmitting node comprises a third-layer processing unit to perform an automatic repeat request retransmission (ARQ) according to a status report returned from the data receiving node. The data transmitting node further comprises a second-layer processing unit to receive, from the third-layer processing unit, a third-layer data unit, segment the third-layer data unit according to the status report and based on a resource allocation, and form a plurality of second-layer data units that include the respective segments of the segmented third-layer data unit.The first-layer processing unit is also present to receive the plurality of second-layer data units from the second layer and map the plurality of second-layer data units over the resources allocated for data transmission. [000176] Consequently, the segmentation functionality is entirely transferred to the second layer, the layer closest to the physical layer. This is illustrated in Figure 10 in greater detail based on a selected example. [000177] The transmitter's RLC layer adds a header to the PDCP PDU (RLC SDU) that includes the query bit (if this mode is applied with AM instead of UM) to request a status report and the D / C field indicating whether the RLC PDU carries a payload (user) or control data. Note that the present description is not limited to the RLC layer executing ARQ, as the RLC layer can also operate in unconfirmed mode. Petition 870240080006, dated 09 / 19 / 2024, p. 67 / 139 61 / 121 [000178] The RLC TX layer provides the status report received from the RLC RX to the MAC layer. The MAC layer reads the segmentation information such as the sequence number (SN), the SOstart and SOend values ​​from the status report and performs the segmentation accordingly. Therefore, the RLC TX takes the complete RLC PDU from the temporary retransmission storage and sends it to the MAC TX. This is illustrated in Figure 10, which shows the RLC PDU, including the data field with 1200 bytes of PDCP SDU data, instead of only 400 bytes. As shown in Figure 8. [000179] Subsequently, the MAC TX layer performs segmentation based on segmentation information, for example SOstart, SOend, and SN, which are indicated by the RLC status report and transferred to the MAC layer by the RLC layer as shown in Figure 10. According to this, the MAC PDU header is generated. The header in Figure 10 includes the LCID (logical channel identifier), the E-bit which indicates whether or not additional header information is present, and the segmentation information which includes the segment offset (which can be in byte units) indicating the start of the segment loaded within the RLC PDU, and the last segment field (LSF) which indicates whether or not the encapsulated RLC PDU segment is the last one in the RLC PDU. As can be seen in Figure 10, the offsets of 801 and 1001 due to the two segments of 200 and 200 bytes respectively are signaled. [000180] Figure 11A shows a status report (STATUS PDU) as defined in 3GPP TS 36.322, v. 13.2.0. A STATUS PDU consists of a STATUS PDU payload and an RLC control PDU header. The RLC control PDU header consists of a D / C field and a CPT. The STATUS PDU payload starts from Petition 870240080006, dated 09 / 19 / 2024, page 68 / 139 62 / 121 first bit following the RLC control PDU header, and this consists of an ACK_SN and an E1, zero or more sets of a NACK_SN, an E1 and an E2, and possibly a set of an SOstart and an SOend for each NACK_SN. When necessary, one to seven padding bits are included at the end of the STATUS PDU to achieve octet alignment. [000181] Figure 11B shows an example format of an RLC status report. This example status report is similar to and includes similar fields to the LTE status report exemplified in Figure 11A. The status report in Figure 11B differs from the LTE status report in Figure 11A in that the PDCP sequence number is carried over instead of the RLC sequence number. [000182] Specifically, the status report includes a D / C field and a CPT (PDU control type) field which indicates whether or not the PDU is a STATUS PDU; this indicates the STATUS PDU for the status report. The PDCP ACK_SN is a 10-bit field which indicates the SN of the next unreceived RLC Data PDU that is not reported as missing in the status report (STATUS PDU). The PDCP prefix here emphasizes that a common SN is used for the RLC and the PDCP layer, which is thus also applied in the status report. [000183] Extension bit 1 (E1) indicates whether or not a set of PDCP NACK_SN, E1 and E2 follows; if set to 0 - a set of NACK_SN, E1 and E2 does not follow; if set to 1 - a set of NACK_SN, E1 and E2 follows. [000184] Negative Confirmation SN (NACK_SN), in this PDCP field, indicates the SN of the RLC PDU (or portions thereof) that was detected as lost on the receiving side of the AM RLC entity. Petition 870240080006, dated 09 / 19 / 2024, p. 69 / 139 63 / 121 [000185] Extension bit 2 (E2) indicates whether or not a set of SOstart and SOend follows; if set to 0 - a set of SOstart and SOend does not follow for this NACK_SN; if set to 1 - a set of SOstart and SOend follows for this NACK_SN. [000186] According to 36.322, sections 6.2.2.18, 6.2.2.19 describe these SOstart and SOend as follows: - SOstart (15 bits): The SOstart field (along with the SOend field) indicates the portion of the RLC PDU with SN = NACK_SN (the NACK_SN to which the SOstart is related) that was detected as lost on the receiving side of the AM RLC entity. Specifically, the SOstart field indicates the position of the first byte of the RLC PDU portion in bytes within the RLC PDU Data field. - SOend (15 bits): The SOend field (along with the SOstart field) indicates the portion of the RLC PDU with SN = NACK_SN (the NACK_SN to which the SOend is related) that was detected as missing on the receiving side of the AM RLC entity. Specifically, the SOend field indicates the position of the last byte of the AMD PDU portion in bytes within the RLC PDU data field. The special SOend value 111111111111111 is used to indicate that the missing portion of the AMD PDU includes all bytes up to the last byte of the AMD PDU. [000187] In other words, SOstart and SOend indicate, respectively, the start and end of the negatively confirmed RLC PDU segments. Segment Number [000188] Segment offsets (start and end together) which are typically 30 bits long, increase the excess MAC subheader processing, especially for smaller segments. Petition 870240080006, dated 09 / 19 / 2024, p. 70 / 139 64 / 121 [000189] In order to reduce processing overload, in this mode, the segment identification is thus a segment number that indicates a segment sequence number of the third-layer data unit within the third-layer data unit. This segment number can be used in the data PDUs as illustrated in the figures, i.e., instead of the SO field. However, the segment number can also be advantageously used in the status report (STATUS PDU) to replace SOstart and SOend. [000190] In one example, the MAC subheader (i.e., the portion of the header related to segmentation) is reduced by using a 4-bit segment number instead of the 30-bit segment offsets (15 bits for SOstart and 15 bits for SOend). Thus, the MAC layer performs segmentation based on the 4 bits that indicate the segment number. The 4-bit segment number allows distinguishing a maximum of 16 segments. However, the number 4 is only for illustrative purposes here. If more or fewer segments are needed for the corresponding user-plane layer architecture, this could be done using a larger number of bits. The purpose of this approach is to reduce processing overhead by assigning a segment number to each segment instead of the start and end of each segment within the RLC PDU.Since the number of segments is certainly smaller than the number of bits in the RLC PDU to which the offsets are related, excess processing is usually saved by addressing the segments instead of the offset. [000191] The use of the segment number is illustrated in Figure 12 for the transmission side. Specifically, Figure 12 shows an IP packet provided to the PDCP layer, where this is added to a D / C field and the PDCP SN is provided together. Petition 870240080006, dated 09 / 19 / 2024, page 71 / 139 65 / 121 with this header information for the RLC layer. The RLC layer encapsulates the PDCP PDU by adding its own header that includes the D / C field and the query field. Here, the RF field is not necessary since segmentation is not performed at the RLC layer. Instead, the entire RLC PDU1 is provided to the MAC layer. [000192] As shown in Figure 12, at the MAC layer, the RLC PDU is divided into two segments: segment 0 and segment 1, which contain 800 and 400 bytes, respectively. This segmentation can be performed based on the allocation size. After segmenting the RLC PDU, the transmitting MAC entity includes the relevant MAC headers to form the MAC PDU. Specifically, the header includes a Length Indicator (LI) that indicates the segment length, the segment number (e.g., the 4 bits described above), the Last Segment Field (LSF), and an R field set to 0 (which indicates that resegmentation does not follow) for the included RLC PDU. The LI field is necessary in the case of concatenation where a MAC PDU contains 2 or more RLC PDUs. In the case of segmentation, the lease size is known, so the receiver knows the lease size and can perform the inverse operation accordingly. [000193] The MAC layer then forms, based on the segmentation information of the two MAC PDUs, which are referred to as MAC PDU1 and MAC PDU2 in Figure 12. MAC PDU1 and MAC PDU2 are sent to the respective transmission time slots TTI0 and TTI1 respectively. Petition 870240080006, dated 09 / 19 / 2024, p. 72 / 139 66 / 121 Table 6 Table 6: MAC Header Fields Length Indicator (LI) The LI field indicates the length in bytes of the corresponding Data field element present in the MAC data PDU provided / received by the MAC entity. For example, in Figure 12, the LI of MAC PDU1 indicates 800 and the LI of MAC PDU2 indicates 400. Extension Bit (E) The E field indicates whether this field is the end of the header or if another extension follows. For example, in Figure 12, the E field is set since additional fields are present in both MAC PDU1 and MAC PDU2. R field indicates whether resegmentation follows. The value of R is initially set to 0. For example, in Figure 12, R = 0 since the respective MAC PDU1 and MAC PDU2 are not additionally segmented. Last Segment Field (LSF) The LSF is set to 1 to indicate that this is the last segment of the RLC PDU.For example, in Figure 12, for MAC PDU1, LSF = 0 since MAC PDU1 is not the last segment of RLC PDU, and for MAC PDU2, LSF = 1 since MAC PDU2 is the last segment of RLC PDU. Last Resegment Field (LRF) The LRF is set to 1 to indicate that this is the last resegment of RLC PDU. For example, in Figure 12, this field is not present since the R field was not determined. Petition 870240080006, dated 09 / 19 / 2024, page 73 / 139 67 / 121 Segment Number: Each segment is assigned a segment number from 0 to 15. For example, in Figure 12, for MAC PDU1, which is the first segment of the RLC PDU, the segment number has a value of 0 (0000 in binary notation, assuming the length of this field is 4 bits), and for MAC PDU2, which is the second and last segment of the RLC PDU, the segment number has a value of 1 (0001 in binary notation). [000194] Figure 13 illustrates an exemplary receiver-side layer processing for this modality in which segment numbers are employed instead of segment offsets. [000195] As shown in Figure 13, on the receiver side, MAC PDU1 is received correctly while MAC PDU2 is lost. The MAC layer provides MAC PDU1 along with the segmentation header (including R, segment number, and LSF) to the RLC layer, while the receiver-side RLC layer sends a status report indicating the missing 800 to 1200 bytes (i.e., MAC PDU2) to the transmitting RLC entity. The RLC layer then performs reassembly and reordering of the RLC segments. Here, only the first 800-byte segment is correctly received, and thus no reordering needs to be performed in this example. [000196] Figure 14 shows an exemplary transmitter-side layer processing when receiving the status report from the data receiver side. As shown in Figure 14, the RLC layer takes the complete RLC PDU from the temporary retransmission storage (this is illustrated by the 1200-byte PDCP SDU data included in the RLC PDU, instead of just the 400 bytes). Petition 870240080006, dated 09 / 19 / 2024, page 74 / 139 68 / 121 missing). The MAC layer then performs segmentation based on the RLC status report. [000197] After RLC PDU re-segmentation, the transmitting MAC entity includes the relevant MAC headers in the respective re-segmented MAC PDUs to indicate their length (LI), a 3-bit re-segmentation number, last re-segmentation field (LRF), and R = 1 (which indicates that a re-segmentation follows) for the respective included RLC PDUs and forms the MAC PDUs which are referred to as MAC PDU1 and MAC PDU2 in Figure 14. [000198] If required, the MAC layer can perform resegmentation of the missing segment number, for example, when the missing segment, as reported in the RLC Status report, cannot fit into the available grant for the corresponding LCID (after performing the LCP). For this purpose, the MAC can use, for example, 3 bits (or more, if required) to identify corresponding segment resegments of an RLC PDU. [000199] In summary, the second-layer processing unit includes within the second-layer data unit header a segment identification comprising a re-segment number indicating a segment sequence number of the third-layer data unit within the third-layer data unit segment, the re-segment number being signaled using fewer bits than the segment number. However, it is noted that this should not limit the present description. The size of the segment number and re-segment number may also be the same. Another term that can be employed for re-segment is a subsegment, since this is a subsegment of a segment resulting from previous segmentation. Petition 870240080006, dated 09 / 19 / 2024, page 75 / 139 69 / 121 [000200] In Figure 14, alternatively, the segment number can be used for segments and the segment offset can be used for subsegments instead of the subsegment number, since it is assumed that retransmissions are not that frequent and thus a higher processing overrun may be acceptable. [000201] Figure 15 shows the receive-side layer processing when receiving the retransmission of MAC PDU1 and MAC PDU2 shown in Figure 14. [000202] As shown in Figure 15, the MAC layer performs a demultiplexing of MAC PDU1 and MAC PDU2 and removes part of their header. However, the MAC layer retains the relevant segmentation header fields (R field, segment number, LSF, LRF, and re-segment number) since reordering and reassembly are performed in the RLC layer. The RLC then performs the reordering and reassembly of the MAC segments and sends the result (PDCP PDU) to the PDCP layer. Reordering and Reassembly in the Second Layer [000203] According to another embodiment of the present description, the receiving side is further modified. Specifically, instead of performing reordering and reassembly at the RLC layer, the MAC layer performs reordering and reassembly. In this case, a cross-layer interaction is not required. In this configuration, the MAC layer is also responsible for performing retransmission processing. If any parts of the segments are missing, then the MAC layer receiving entity sends the status report to the MAC TX. The MAC status report will differ slightly from the RLC status report. Specifically, the LCID field will be provided in the status report to differentiate which status report belongs to which LCID (channel). Petition 870240080006, dated 09 / 19 / 2024, p. 76 / 139 70 / 121 logical). [000204] In other words, a data receiving node for receiving data over a wireless interface in a communication system from a data transmission node comprises: a first-layer processing unit for unmapping one or more of a plurality of second-layer data units from the resources allocated for data transmission and for providing one or more of the plurality of unmapped second-layer data units to the second-layer processing unit; the second-layer processing unit for performing demultiplexing of a plurality of third-layer unit segments and segmentation control information from one or more of the plurality of second-layer data units, and transferring the plurality of demultiplexed third-layer unit segments along with the segmentation control information to a third-layer processing unit;Furthermore, the second-layer processing unit is also performing reordering of the plurality of demultiplexed third-layer unit segments and assembling the demultiplexed third-layer unit segments into a third-layer data unit. The second-layer processing unit may also be configured to verify whether or not the data is received correctly and send a status report to the point second-layer entity. This receiver mode is specifically suited for the receiver mode with the segmentation / concatenation performed in the second layer described above. Multiple Connectivity / Dual Connectivity for More eNBs, Same Carrier for More Connections. Petition 870240080006, dated 09 / 19 / 2024, page 77 / 139 71 / 121 [000205] In the case of multiple connectivity, the PDCP layer distributes duplicate packets across different eNBs. [000206] The following Table 7 describes a multi-connectivity protocol stack with the main functions of each layer. Table 7 Table 7: Protocol layer functions that support multiple connectivity PDCP TX Functions - Header compression - SN appending - Encoding - Packet segmentation on retransmission RLC TX MAC TX - Concatenation / multiplexing - Segmentation - HARQ transmission MAC RX - HARQ reception - Demultiplexing RLC RX PDCP RX - Packet decoding - Reordering / reassembly / segment-based status reporting - Full PDU reporting based on reordering / status - Header decompression [000207] Figure 16 illustrates transmission-side layer processing for a case of a new transmission of an IP packet 1 according to this mode that supports multiple connectivity. [000208] Specifically, the first layer is a physical layer, the second layer is a Medium Access Control layer, Petition 870240080006, dated 09 / 19 / 2024, pp. 78 / 139 72 / 121 The third layer is a Packet Data Control Protocol (PDCP) layer. However, it is noted that the PDCP and RLC layers can also be combined into one layer, or RLC can perform the functionality. The third-layer processing unit is configured to provide the same third-layer data unit to different lower-layer stacks for transmission, over the wireless interface, to different respective base stations, or, in general, data receiving nodes. The lower-layer stacks are capable of performing segmentation / reassembly individually and independently of each other. The lower-layer stack may include a physical layer and a MAC layer. However, it may also still include the RLC layer. [000209] As also noted above, the layer may also be named differently and have different functions than the current LTE layers. In general, multiple connectivity has a common layer which receives a packet from higher layers and provides multiple (more than one) copies of the encapsulated packet as its own PDU for the lower layers of the respective multiple stacks. The multiple stacks handle segmentation and reassembly as described in any of the above modes and separately and independently of each other, which ensures that they can adapt to their respective physical channel conditions and data reception status. [000210] The third layer advantageously controls the retransmission processing. In the multiple connectivity scenario described above, it is not necessary for each lower-layer stack on the receiving side to correctly reassemble the packet. It is sufficient when one of these stacks, which collects packet segments from all other stacks, is able to reassemble the packet. This provides a Petition 870240080006, dated 09 / 19 / 2024, pp. 79 / 139 73 / 121 type of diversity and increases yield. [000211] As shown in Figure 16, IP packet 1 is attached to the PDCP header over the PDCP layer, and the corresponding PDCP PDU is sent to two different base stations, here eNB1 and eNB2. The base stations eNB1 and eNB2 (network nodes) implement protocol layers as described above (RLC / MAC / PHY), respectively. eNB1 passes the PDCP PDU corresponding to RLC PDU1 in two segments, MAC PDU1 and MAC PDU2, containing 800 bytes and 400 bytes respectively. eNB2 may employ a different segmentation since the channel quality in different cells may differ. Thus, in this example, eNB2 segments RLC PDU1 into two segments, MAC PDU1 and MAC PDU2, containing 500 bytes and 700 bytes respectively. The RLC layer, if operating in confirmed mode, may also be responsible for ARQ functionality. However, as described above, PDCP can control RLC retransmissions.Specifically, each RLC layer (of the respective eNB) can pass status reports to the PDCP of the master eNB, which decides whether or not a retransmission is necessary and for which packet segment. The PDCP then instructs the respective RLC layers to perform the retransmissions accordingly. [000212] Figure 17 illustrates the processing on the receive side. As shown in Figure 17, eNB1 receives MAC PDU1 which contains 0 to 800 bytes while MAC PDU2 with 801 to 1200 bytes is lost. On the other hand, eNB2 receives MAC PDU1 which contains 0 to 500 bytes while 501 to 1200 bytes are lost due to the lack of MAC PDU2. The PDCP layer performs central reordering and reassembly. [000213] One advantage of not performing reordering and reassembly in the RLC layer in this mode is to avoid Petition 870240080006, dated 09 / 19 / 2024, p. 80 / 139 74 / 121 unnecessary retransmissions during multiple connectivity. If reassembly and reordering were performed at the RLC layer, then the RLC layer of both eNBs would send respective individual RLC status reports to the RLC TX (eNB1's RLC sends the status report from 801 to 1200 bytes and eNB2's RLC sends the status report from 501 to 1200 bytes, so far the missing part is 801 to 1200 bytes). In this case, the RLC TX could retransmit more than the required segments, which would be discarded at the RLC RX. [000214] To overcome this problem, the RLC layer in this mode operates as transparently as possible, and the central reordering and reassembly functions are performed at the PDCP layer. In order to perform reordering and reassembly, the PDCP layer needs to understand the segment header (SO and LSF) of the MAC layer, since the segmentation is being performed on the MAC.The PDCP receives the PDUs from the MAC layer and performs reordering and reassembly, similarly to what is described in the modes above for the RLC layer. It overlays common segments and sends a status report indicating only the missing part of the segments, that is, the part that was not correctly received by any of the eNBs. [000215] When observing Figure 17, it can be seen that MAC PDUs include segmentation information as described above, i.e., SO and LSF. However, similarly to other modes, segmentation information may include segment numbers and segment lengths instead. Furthermore, Figure 15 shows the use of PDCP SN also in the RLC layer to reduce processing overhead. However, the present description is not limited to this, and in general, separate sequence numbers can be used for the PDCP and RLC layers, as is currently the case in LTE. Petition 870240080006, dated 09 / 19 / 2024, page 81 / 139 75 / 121 As mentioned above, a cross-layer design can improve transmission efficiency. Specifically, the status report is advantageously transmitted and received over the layer (RLC) below the coordination layer (third, PDCP) and provided to the coordination layer to match received segments and decide which segments should be transmitted. Furthermore, MAC segmentation information can be passed to the coordination layer to allow reordering and reassembly, as well as coordination of retransmissions. [000216] However, it is noted that the present description may still work, even if slightly less efficiently, if the PDCP does not perform retransmission coordination and if segments are actually redundantly retransmitted over each connection. Advantageously, in Figure 17, the PDCP RX sends a status report of 801 to 1200 missing bytes. Advantageously, this status report is sent to both (usually multiple) eNBs, so that diversity is achieved by retransmission over both connections. However, the present description is not limited to this and generally, for the purpose of retransmission, a single connectivity may be re-established. [000217] As shown in Figure 18, the PDCP TX, upon receiving the status report, takes a complete PDCP PDU (1200 bytes) from the temporary transmission storage and performs a resegmentation (extraction) of the 800 to 1200 bytes indicated by the PDCP status report, and then the 800 to 1200 byte PDU segment (resegmented PDU) is provided to the MAC. The MAC layer of each eNB performs its own segmentation according to the resource allocation as described in the modalities above. In this case, as can be seen in Figure 18, the adjustments of MAC entity segments (transmitting to Petition 870240080006, dated 09 / 19 / 2024, page 82 / 139 76 / 121 eNB1) the 800-1200 bytes for two MAC PDUs, namely MAC PDU1 with 800 to 900 bytes and a second MAC PDU2 with 901 to 1200 bytes. On the other hand, the second MAC entity segments (transmitting to eNB2) the 800-1200 bytes for a first MAC PDU1 with the bytes 801-1000 and a second MAC PDU2 with the bytes 1001 to 1200. [000218] In general, there are also alternatives: With the above described, PDCP takes the complete PDU from the temporary transmission store and then performs resegmentation of the missing packet, which is indicated by the PDCP status report. [000219] However, alternatively, the PDCP status report can be understood by the MAC layer and therefore, PDCP passes the complete PDU to the MAC, instead of performing resegmentation. The MAC will then perform segmentation based on the PDCP status report. [000220] Yet another possibility is that the PDCP will inform the RLC about the missing segment(s). Subsequently, the RLC layer will send the status report to the RLC TX. [000221] Correspondingly, Figure 19 shows the receiving side (network side in this uplink data transmission example) when receiving the retransmissions from Figure 18. Specifically, in this example, all segments are correctly received at the MAC and demultiplexed. The RLC basically passes the received segments along with the segmentation information received from the MAC to the PDCP, and the PDCP performs the reordering and reassembly of all received segments from all nodes of the multi-link (here eNB1 and eNB2). [000222] Figure 20 illustrates the transmitting apparatus 2000t and the receiving apparatus 2000r as parts of a communication system 2000 and communicating on a channel 2090. Petition 870240080006, dated 09 / 19 / 2024, page 83 / 139 77 / 121 Specifically, the fourth-layer processing unit 2040t, the third-layer processing unit 2030t, the second-layer processing unit 2020t, and the first-layer processing unit 2010t perform the processing of the corresponding layers as described in the embodiments above. The transmitter 2050 transmits through its antenna(s) the signal mapped onto the physical resources. The receiving apparatus 2000r correspondingly comprises the fourth-layer processing unit 2040r, the third-layer processing unit 2030r, the second-layer processing unit 2020r, and the first-layer processing unit 2010r, and a receiver 2060 which receives the signal transmitted over its antenna(s). [000223] Figure 21 exemplifies one of the embodiments of methods according to the present description.Specifically, on the left side, a method executed on the data transmission side is illustrated, while on the right side, a method executed on the data reception side is exemplified. [000224] The transmission method may include steps performed by the third layer including receiving 2120t a 3rd-layer SDU, generating 2120t a PDU based on it, for example, by attaching a header, and passing 2130t the PDU to the second layer. Second-layer processing may then include the third-layer PDU as a second-layer SDU 2140t, performing segmentation or concatenation 2150t as described above, based on the received allocation (and in some modes also based on the status report), and passing the thus formed PDU to the first layer in step 2160t. First-layer processing then includes receiving 2170t the SDU from the second layer, mapping it to physical resources 2180t, and transmitting 2190t. [000225] At the receiver, as part of first-line processing Petition 870240080006, dated 09 / 19 / 2024, page 84 / 139 In layer 78 / 121, reception 2190r is performed, then the data is unmapped from the physical resources 2180r and passed 2170r to the second layer. Second-layer processing includes receiving the PDU 2160r, demultiplexing it 2150r, and passing it 2140r to the third layer for reordering and reassembly (as described above, in an alternative embodiment, reordering and reassembly are also performed in the second layer). Third-layer processing includes receiving the PDU 2130r, performing reordering and reassembly 2120r, and passing the reassembled packet to the upper layers 2110r. [000226] There are also modes that implement the retransmission mechanism over the third layer, including transmitting a status report on the data receiving side and receiving the status report on the data transmitting side. If the status report includes negative acknowledgment for some segments (2125, yes), resegmentation is performed over the third layer (alternatively, in some modes on the second layer). [000227] In summary, according to one embodiment of the present description, a data transmission node is provided for transmitting data over a wireless interface in a communication system to a data reception node, comprising: a third-layer processing unit for performing an automatic repeat request retransmission, ARQ, according to a status report returned from the data reception node and for resegmenting or not the data to be retransmitted based on segment length information included in the status report which includes adding segmentation control information to the data; a second-layer processing unit for receiving, from the third-layer processing unit Petition 870240080006, dated 09 / 19 / 2024, page 85 / 139 79 / 121 layer, a third-layer data unit, segments the third-layer data unit based on a resource allocation and forms a plurality of second-layer data units that include the respective segments of the third-layer data unit and the segmentation control information which is modified if a resegmentation is to be applied; and a first-layer processing unit to receive from the second layer one or more of the plurality of second-layer data units and map one or more of the plurality of second-layer data units over the resources allocated for data transmission. [000228] According to another embodiment of the present description, a data transmission node is provided for transmitting data over a wireless interface in a communication system to a data reception node, comprising: a third-layer processing unit for performing an automatic repeat request retransmission, ARQ, in accordance with a status report returned from the data reception node; a second-layer processing unit for receiving, from the third-layer processing unit, a third-layer data unit, segmenting the third-layer data unit in accordance with the status report and based on a resource allocation and forming a plurality of second-layer data units that include the respective segments of the segmented third-layer data unit;and a first-layer processing unit to receive from the second layer one or more of the plurality of second-layer data units and map one or more of the plurality of second-layer data units over the resources allocated for data transmission. Petition 870240080006, dated 09 / 19 / 2024, page 86 / 139 80 / 121 [000229] According to another embodiment of the present description, a data receiving node is provided to receive data over a wireless interface in a communication system from a data transmitting node, comprising: a first-layer processing unit for unmapping one or more of a plurality of second-layer data units from the resources allocated for data transmission and for providing one or more of the plurality of unmapped second-layer data units to the second-layer processing unit;The second-layer processing unit performs demultiplexing of a plurality of third-layer unit segments and segmentation control information from one or more of the plurality of second-layer data units, and transfers the plurality of demultiplexed third-layer unit segments along with the segmentation control information to a third-layer processing unit; the third-layer processing unit performs reordering of the plurality of demultiplexed third-layer unit segments and assembly of the demultiplexed third-layer unit segments into a third-layer data unit. [000230] Furthermore, a method is provided for transmitting data over a wireless interface in a communication system to a data receiving node, comprising: performing third-layer processing that includes performing an automatic repeat request retransmission, ARQ, according to a status report returned from the data receiving node and for resegmenting or not resegmenting data to be retransmitted based on segment length information included in the status report that includes adding control information to the data. Petition 870240080006, dated 09 / 19 / 2024, page 87 / 139 81 / 121 segmentation; perform second-layer processing that includes receiving a third-layer data unit from the third-layer processing unit, segmenting the third-layer data unit based on a resource allocation, and forming a plurality of second-layer data units that include the respective segments of the third-layer data unit and the segmentation control information, which is modified if a resegmentation is to be applied; and perform first-layer processing that includes receiving one or more of the plurality of second-layer data units from the second layer and mapping one or more of the plurality of second-layer data units over the resources allocated for data transmission. [000231] Furthermore, a method is provided for transmitting data over a wireless interface in a communication system to a data receiving node, comprising: a third-layer processing that includes performing an automatic repeat request retransmission, ARQ, according to a status report returned from the data receiving node; a second-layer processing that includes receiving, from the third-layer processing unit, a third-layer data unit, segmenting the third-layer data unit according to the status report and based on a resource allocation, and forming a plurality of second-layer data units that include the respective segments of the segmented third-layer data unit;It is a first-layer processing process that includes receiving one or more of the plurality of second-layer data units from the second layer and mapping one or more of the plurality of second-layer data units over the resources allocated for data transmission. Petition 870240080006, dated 09 / 19 / 2024, page 88 / 139 82 / 121 [000232] Furthermore, a method for receiving data over a wireless interface in a communication system from a data transmission node, comprising: first-layer processing which includes unmapping one or more of a plurality of second-layer data units from the resources allocated for data transmission and providing one or more of the plurality of unmapped second-layer data units to the second-layer processing unit; second-layer processing which includes performing demultiplexing of a plurality of third-layer unit segments and segmentation control information from one or more of the plurality of second-layer data units, and transferring the plurality of demultiplexed third-layer unit segments together with the segmentation control information to a third-layer processing unit;Third-layer processing includes performing reordering of the plurality of demultiplexed third-layer unit segments and assembling the demultiplexed third-layer unit segments into a third-layer data unit. MAC subheaders [000233] MAC PDUs are byte-aligned bit strings. A MAC PDU includes at least MAC subheaders associated with MAC control elements and / or MAC SDUs, and, if required, padding. A MAC control element is used for signaling between MAC endpoints in the eNB and UE. A MAC SDU contains top-layer (RLC) data; consequently, MAC SDUs correspond to RLC PDUs. An RLC PDU contains user data for a service. A MAC PDU includes a subheader for each MAC control element and for each MAC SDU. Petition 870240080006, dated 09 / 19 / 2024, p. 89 / 139 83 / 121 [000234] Each subheader includes a Logical Channel ID (LCID). In a subheader associated with a MAC control element, the LCID points to the control element type of the respective loaded MAC control element. In a subheader associated with a MAC SDU, the LCID indicates the identity of the logical channel to which the respective loaded RLC PDU belongs. User Plane Protocol Stack [000235] Figure 22 shows an exemplary structure of a user plane protocol stack. From top to bottom, the arrangement of different data units in the third layer and the second layer is shown. The top row refers to the third layer SDU, the second row refers to the third layer PDU, the third row refers to the second layer SDU, and the bottom row refers to the second layer PDU. In one embodiment shown in the figure, the third layer corresponds to the RLC layer of the user plane, and the second layer corresponds to the MAC layer of a user plane. Not shown in the figure is the fourth layer, which in the discussed embodiment corresponds to the PDCP layer of the user plane. The third layer and the second layer are visually separated by a dashed line. [000236] Data units are passed from the RLC layer to the MAC layer through logical channels (LCs). In Figure 22, two logical channels with logical channel identifiers LCID1 and LCID2 are shown. Signaling and user data belonging to the channel with LCID1 are marked by solid line frames, and the data elements associated with LCID2 are marked by dashed line frames. As can be seen in the figure, different amounts of data units can be provided through different logical channels. In the example shown, in the top line associated with the third-layer SDUs, two data units are displayed. Petition 870240080006, dated 09 / 19 / 2024, pp. 90 / 139 84 / 121 of the top row, corresponding to the third-layer SDU, belong to a first logical channel with LCID1 (the data units identified as PDCP PDU1 and PDCP PDU2), while one data unit belongs to a second logical channel with LCID2 (PDCP PDU1). Since third-layer SDUs can be identified by their corresponding logical channel, two third-layer SDUs operated by two different logical channels have the same identification, PDCP PDU1 in the figure. However, the present description is not restricted to the case shown in Figure 22; alternatively, different logical channels can operate the same amount of data to be allocated to a TB. There may also be only one logical channel or more than two logical channels. [000237] Through the different logical channels with identifiers LCID1 and LCID2, fourth-layer PDUs (identified PDCP PDU1, PDCP PDU2, and PDCP PDU1) are received by the third-layer processing unit from the fourth-layer processing unit to be processed as third-layer SDUs. By adding a third-layer header that includes a sequence number (referred to as RLC SN) to each of the fourth-layer PDUs that correspond to third-layer SDUs, the third-layer processing unit generates third-layer PDUs, each of which consists of a third-layer header and a third-layer SDU. The third-layer PDUs are then transferred to the second layer, which receives them as second-layer PDUs.Although the third-layer SDUs shown in the second row are identical to the second-layer PDUs shown in the third row, these identical data units are shown twice in Figure 22, which is for illustrative purposes only. [000238] The second-layer processing unit receives Petition 870240080006, dated 09 / 19 / 2024, pp. 91 / 139 85 / 121 Second-generation SDUs from the third layer generate a second-layer PDU, which is shown in the bottom row of Figure 22, by concatenating one or more second-layer SDUs with some second-layer control information and possibly padding. In the generation of the second-layer PDU, different data elements are concatenated. Specifically, second-layer subheaders are provided for the respective user data and control elements, identified respectively as MAC LCID 0 + L, MAC LCID 1 + L, MAC LCID 2 + L, MAC LCID P. Here, the identification indicates that the subheader carries prioritization control information corresponding to the respective LCIDs (since priorities are assigned to the respective LCIDs) and length information (L). Second-layer control elements (identified as MAC CE) can also be inserted into the second-layer PDU as well as padding, if necessary.In the figure, the padding at the end of the MAC PDU is shown with a corresponding subheader for padding (MAC LCID P). A case where padding is preceded by a corresponding subheader may be the Padding BSR, which may be included in a MAC PDU instead of mere padding. For the Padding BSR, see also 3GPP TS 36.321 v 13.3.0, section 5.4.5, incorporated herein by reference. [000239] It is noted that in some LTE versions, padding may have a corresponding subheader assigned, depending on the padding length. Specifically, padding is inserted at the end of the MAC PDU except when single-byte or two-byte padding is required. When single-byte or two-byte padding is required, one or two MAC PDU subheaders representing the padding are Petition 870240080006, dated 09 / 19 / 2024, p. 92 / 139 86 / 121 placed at the beginning of the MAC PDU before any other MAC PDU subheader. [000240] In LTE terminology, Figure 22 shows PDCP PDUs (representing respective RLC SDUs) from two different logical channels concatenated into a single MAC PDU. In this case, after concatenating the three MAC SDUs corresponding to the two logical channels and adding the corresponding MAC subheader to the beginning of each, there is still some space left in the allocated resources. In this space, one or more MAC CEs are advantageously inserted. If there is still more space left, padding is applied. Providing respective MAC subheaders instead of a single MAC header for the MAC PDU allows at least partial pre-processing of the MAC PDU. [000241] Correspondingly, the user plane protocol stack shown in Figure 22 and discussed above is an exemplary user plane protocol stack for NR. With such a user plane, preprocessing of third-layer headers and second-layer headers is possible. Specifically, a second-layer SDU with its associated second-layer header can be provided to the first layer before a complete TB (the complete MAC PDU) has been constructed. This, in turn, allows for a reduction in processing latency. [000242] The advantages relating to enabling the aforementioned processing delay reduction result from a suitable second-layer (MAC) PDU format as provided by the embodiments of the present description. In the following, different alternative configurations of second-layer PDU formats are described with respect to Figures 23 to 30. Although it is assumed in these figures that the second layer corresponds to the MAC layer, the present description is not restricted to the case in Petition 870240080006, dated 09 / 19 / 2024, pp. 93 / 139 87 / 121 which is the second layer, the MAC layer. [000243] Figure 23 is a schematic drawing showing an exemplary second-layer PDU that corresponds to the user-plane protocol stack described in relation to Figure 22. The second-layer PDU includes two second-class SDUs, two second-layer control elements (CE), and their respective four corresponding second-layer subheaders, and padding. A respective second-layer subheader is associated with each of the second-layer SDUs and with each of the second-layer control elements. Each of the second-layer subheaders precedes the second-layer SDU or, respectively, the second-layer control element with which it is associated. This association is indicated in the figure by arrows pointing from each second-layer subheader to the respective second-layer control element or second-layer SDU.The same arrow notation is used in Figures 24 to 30 to denote the association of a second-layer subheader. In the second-layer PDU format shown in Figure 23, the second-layer control elements are placed before all second-layer SDUs, that is, before any of the second-layer SDUs. In other words, each of the second-layer control elements precedes each of the second-layer SDUs. Padding is placed at the end of the second-layer PDU. However, in this second-layer PDU format, padding is a merely optional component of the second-layer PDU, only applicable if there is some remaining space left in the MAC PDU length that corresponds to the allocated physical resources, the remaining space being too small to accommodate any other MAC SDU or MAC CE to be transmitted. This... Petition 870240080006, dated 09 / 19 / 2024, pp. 94 / 139 88 / 121 also applies to any second-tier PDU format according to any embodiment to be described in the remainder of this description. [000244] In Figure 23, the number of second-layer PDUs and the number of second-layer control elements are both two. However, the present description is not limited to a specific number of second-layer control elements or a specific number of second-layer SDUs. Instead of suggesting a specific number of second-generation control elements or second-layer SDUs, the figure illustrates the specific order of second-layer subheaders, second-layer SDUs, second-layer control elements, and the padding within the second-layer PDU. [000245] As already mentioned with reference to Figure 22, the arrangement in Figure 23 provides the advantage that each MAC CE or MAC SDU with its corresponding subheader can be individually provided to the lower layer without waiting for the entire MAC PDU to be assembled. [000246] A disadvantage of the second-layer PDU format in Figure 23 is that any second-layer control elements are placed before any second-layer SDUs; the second-layer processing unit can only provide available second-layer SDUs to the physical layer after the second-layer control elements have been computed. However, in order to compute some MAC CEs, calculations such as the prioritization procedure must be completed. On the other hand, the preparation of some MAC SDUs may take less time. However, these cannot be provided to the physical layer before the MAC CEs have been calculated. Petition 870240080006, dated 09 / 19 / 2024, pp. 95 / 139 89 / 121 Efficient MAC Control Element Signaling [000247] In order to resolve the aforementioned disadvantage, Figure 24 shows an advantageous embodiment of a MAC PDU, in which any MAC SDU precedes any MAC CE. Specifically, the MAC PDU 2400 begins with a first MAC SDU 243a preceded by a subheader 241a associated with it. The first MAC SDU is followed by a second MAC SDU 243b with its respective header 241b. In this example, there are only two MAC SDUs, the logical channel ID (priority) of which can be signaled in their respective subheaders. However, in the present embodiment, the MAC PDU can include more than two MAC SDUs. The MAC PDU 2400 still comprises a subheader of MAC 242a associated with a first MAC CE 244a followed by the subheader of MAC 242b associated with a second MAC CE 244b. The subheadings of MACs 242a and 242b precede their respective MAC CE, 244a or 244b, with which they are associated.As shown in the figure, MAC CE 244a and MAC CE 244b, as well as their respective subheaders MACs 242a and 242b, follow either MAC SDU 243a or MAC SDU 243b and their respective subheaders 241a and 241b. [000248] This embodiment is not limited to the case where there are two MAC CEs. There may be only one MAC CE or more than two MAC CEs. Furthermore, a case is shown in the figure where the number of MAC CEs is equal to the number of MAC SDUs. However, the number of MAC CEs may be different from the number of MAC SDUs. In a MAC PDU according to this embodiment, there may be fewer MAC CEs than there are MAC SDUs or, alternatively, there may be more MAC CEs than MAC SDUs. It is a feature of this embodiment that any MAC CE and any MAC subheader associated with any MAC CE follows Petition 870240080006, dated 09 / 19 / 2024, pp. 96 / 139 90 / 121 any MAC PDU or any subheader associated with any MAC PDU. Optionally, a 245 padding can be added. If the full resources of a TB are used for MAC SDUs, MAC CEs, and their respective MAC subheaders, the padding can be omitted. [000249] In general, padding is inserted if, after mapping the MAC SDUs and MAC CEs along with their respective MAC subheaders, there are still some free resources between the resources allocated for transmission and these free resources are not sufficient to drive any additional MAC CE or MAC SDU. [000250] Thus, a data transmission node for transmitting data over a wireless channel to a data reception node in a 3100 communication system can generate MAC PDUs as exemplified in Figure 24, thereby allowing a reduction in processing delay. Specifically, such a node may correspond to the 3100t device illustrated in Figure 31, and comprise a second-layer processing unit 3120t and a first-layer processing unit 3110t. The second-layer processing unit 3120t is suitable for receiving, from a third-layer processing unit 3130t, at least one second-layer service data unit, SDU, to be mapped onto a resource allocated for data transmission, and to generate a second-layer PDU.The second-layer PDU generated by the second-layer processing unit includes at least one second-layer SDU received from the third layer and at least one second-layer control element, with at least one second-layer control element following any of the at least one second-layer SDUs. The first-layer processing unit 3110t is suitable for receiving the second-layer PDU. Petition 870240080006, dated 09 / 19 / 2024, pp. 97 / 139 91 / 121 generated by the second-layer processing unit and map the second-layer PDU over the resource allocated for data transmission. [000251] On the other hand, the receiving node for receiving data over a wireless channel from a data transmission node in a 3100 communication system can receive and process MAC PDUs as exemplified in Figure 24, thereby allowing a reduction in processing delay. Specifically, such a node can correspond to the 3100r device illustrated in Figure 31, and comprises a first-layer processing unit 3110r and a second-layer processing unit 3120r. Here, the first-layer processing unit 3110r is suitable for unmapping at least one second-layer protocol data unit, PDU, from a resource allocated for data reception. Furthermore, the second-layer processing unit 3120r is suitable for receiving and analyzing the second-layer PDU unmapped by the first-layer processing unit.Such a second-layer PDU received and analyzed by the second-layer processing unit includes at least one second-layer SDU, to be transferred to a third-layer processing unit 3130r included in the data receiving node 3100r, and at least one second-layer control element, the at least one second-layer control element following any of the at least one second-layer SDU. [000252] Advantageously, the second-layer PDU to be generated by the second-layer processing unit of the data transmission node and, correspondingly, the second-layer PDU to be received and analyzed by the second-layer processing unit of the data reception node still include a Petition 870240080006, dated 09 / 19 / 2024, pp. 98 / 139 92 / 121 respective second-layer subheader associated with each of at least one second-layer SDU, and a respective second-layer subheader associated with each of at least one second-layer control element. As mentioned above, providing a plurality of respective MAC subheaders within the MAC PDU instead of a single MAC header allows portions of the MAC PDU to be transferred to lower layers instead of the entire MAC PDU. This, in turn, reduces latency since some portions of the MAC PDU can be processed earlier by the lower layers. [000253] It is noted that in some systems, subheaders for MAC CEs and / or SDUs may be unnecessary. In systems such as LTE, a subheader may typically include a channel type indication and a length indication. The channel type indication may serve to prioritize specific MAC PDU portions. The length indication specifies the length of the corresponding data portion, such as the length of the MAC SDU and / or MAC CE. However, in some systems, the MAC SDU may have a predefined length or a length configured in another way, so the length indication may not be necessary either. [000254] Figure 25 illustrates an example of a subheader format for a MAC SDU, which is similar to the known format of the current LTE standard (see also 3GPP TS 36.321 v 13.3.0 Section 6.2.1, incorporated here by reference). A MAC PDU that has the same format as shown in Figure 24 is shown, and the format of a MAC subheader is exemplified by a MAC subheader associated with a MAC SDU (identified MAC SDU2 in the figure). This MAC SDU corresponds to MAC SDU 243b, and its associated MAC subheader corresponds Petition 870240080006, dated 09 / 19 / 2024, pp. 99 / 139 93 / 121 to the MAC 241b subheader shown in Figure 24. Consequently, a MAC subheader includes reserved bits (R), a format2 field (F2), an extension field (E), and a Logical Channel ID (LCID) field. It further includes a length field (L) and a format field (F) if the subheader is associated with a MAC SDU or a variable-length MAC control element. [000255] The extension field E can be a one-bit field. In LTE, the R / F2 / E / LCID line has an octet length (byte, i.e., 8 bits), where the R field is one bit long, the F2 field is one bit long, the E field is one bit long, and the LCID is 5 bits long. In LTE, F2 = 1 indicates that the size of the corresponding MAC SDU or variable-length control element is greater than 32767 bytes (corresponding to the 15-bit length field), and that the subheader is not the last subheader in the MAC PDU. The extension field E indicates the presence of another MAC subheader in the PDU. Specifically, a value of E = 1 indicates that at least one more MAC subheader that includes at least R / F2 / E / LCID fields (and thus possibly also the corresponding SDU or CE) follows in the parsing direction in the MAC PDU. The direction of analysis in LTE is assumed to be from the beginning of the MAC PDU (starting with the header) towards the end.This is also the case in Figure 25, where the direction of analysis is from left to right. [000256] In Figure 24, this additional octet is shown in the second line of the subheader with the F and L fields. In general, if the header has only one octet, the length field L is not present. Thus, the MAC SDU length cannot be signaled. In LTE, a second octet is not included in the MAC subheader if the MAC subheader is associated with Petition 870240080006, dated 09 / 19 / 2024, pp. 100 / 139 94 / 121 is a fixed-length MAC control element. In this case, the length of the fixed-length MAC control element is known from the LCID, which specifies the type of MAC control element. The F field indicates the length of the L field, which, in LTE, can be 7 bits or 15 bits long (thus extending over either one or two octets). The R field is reserved in the current LTE standard but may be replaced by another indicator or indicators in future versions of the standard. In other words, in a receiver operating according to the current standard, the R field is ignored. [000257] As will be discussed below, the direction of analysis can generally be from the beginning of the MAC PDU towards the end of the MAC PDU or vice versa, depending on the format of the MAC PDU. [000258] For MAC subheader fields in LTE, see also 3GPP TS 36.321 v 13.3.0. Chapter 6.2.1, incorporated herein by reference. [000259] The LCID field has, for example, 5 bits as in LTE, and indicates the subheader type and logical channel or, if the subheader is associated with a control element, the control element type. Here, the subheader type means whether the subheader is a CE MAC subheader or an SDU MAC subheader or anything else (e.g., reserved, padding, etc.). The subheaders of the respective CE MAC types define the CE MAC type uniquely. For example, 11101 means short BSR, 11010 means PHR, while 11011 means C-RNTI and 11111 means padding. [000260] The L-length field in LTE can have 7 or, alternatively, 15 bits, and this indicates the length of the MAC SDU, or respectively, the length of the MAC control element, depending on whether the subheader is associated with a MAC control element or a MAC SDU. In the L-field, the length of the Petition 870240080006, dated 09 / 19 / 2024, pp. 101 / 139 95 / 121 The MAC SDU, or MAC control element, is given in bytes. Furthermore, the format field F can be a 1-bit field indicating the length of the L field. For example, a value of F = 0 might indicate that the L field has 7 bits, while F = 1 might indicate that the L field has 15 bits. [000261] However, it is noted that the present description is not limited to the subheader format of the current LTE standard. The lengths and values ​​for the E, LCID, F, and L fields are examples that correspond to an advantageous implementation of a MAC subheader. However, a MAC subheader that has a structure that corresponds to an embodiment of the present description may be implemented using different field lengths or variable values. [000262] An exemplary MAC PDU according to an exemplary embodiment of the present description is shown in Figure 26. The format of the MAC PDU corresponds to the MAC PDU format shown in Figure 24. The MAC PDU shown in Figure 26 includes: MAC SDUs and a MAC control element, all of which are preceded by their respective MAC subheaders. At the end of the MAC PDU, a padding is shown as an optional component. In this example, only one MAC control element is shown, namely a BSR MAC control element. However, in correspondence with the MAC PDU format illustrated in Figure 24, the MAC control element and its respective MAC subheader are placed after each MAC SDU (MAC SDU1 and MAC SDU2 in the figure) and their respective MAC subheaders.Although not shown in the figure, instead of a BSR MAC control element, a different type of MAC control element plus its associated subheader can be placed after each MAC SDU and the respective MAC subheader of each MAC SDU included in it. Petition 870240080006, dated 09 / 19 / 2024, pp. 102 / 139 96 / 121 MAC PDU. For example, the MAC control element can also be a power tolerance report, BSR (short, long, or truncated), or C-RNTI. Consequently, the second-layer control element is any one of a temporary storage status report, C-RNTI, and a power tolerance report, and each second-layer subheader associated with any temporary storage status report, C-RNTI, or power tolerance report is placed after each of at least one second-layer SDU. [000263] In the MAC PDU according to the modality shown in Figure 24, MAC CEs (e.g., BSR MAC CEs, and PHR MAC CEs) and their associated MAC subheaders are always placed after any MAC SDUs, while MAC SDUs and their associated MAC subheaders are located at the beginning of a MAC PDU that corresponds to a TB. Therefore, the start of the MAC PDU does not depend on the MAC CEs. For example, it does not depend on the complete LCP result in the case of the MAC CE being a BSR, and the PHR calculation depends on PHY inserting that value for MAC. This independence allows sending the start of the MAC PDU (when the first MAC SDU is ready) to the first-layer processing unit (PHY) even before the MAC PDU has been fully constructed.Consequently, the second layer (MAC) can begin transferring packets to the first layer (PHY) when the first layer SDU is ready, and the second layer processing unit does not need to wait for the second layer PDU to assemble the entire second layer PDU before transferring the packets belonging to the second layer PDU to the lower layer(s). This is beneficial for reducing transmission processing latency and allows more processing time for the sender, i.e., the data transmission node, to compute the BSR, etc. Petition 870240080006, dated 09 / 19 / 2024, pp. 103 / 139 97 / 121 PHR, since both the BSR MAC control elements and the PHR MAC control elements are located at the end of a TB, that is, after any MAC SDUs included in the MAC PDU. [000264] One advantage of using a MAC PDU format as shown in Figures 24 and 26 and, correspondingly, a MAC subheader structure as shown in Figure 25, is that most MAC and MAC SDU subheaders, except for the last one subject to segmentation, can be pre-processed. However, despite such a MAC PDU format being transmitter-friendly, it could be important for the receiver to receive and process certain types of MAC CEs as soon as possible, i.e., enabling / disabling MAC CEs and UE contention resolution MAC CEs in downlink (transmitted from eNB to UE) or C-RNTI in uplink (from UE to eNB). Consequently, in LTE this was the main reason for placing MAC CEs before any MAC SDUs in a MAC PDU. [000265] Advance processing of MAC control elements of certain types (such as enabling / disabling MAC CEs and contention resolution MAC CEs in DL or the C-RNTI in UL) can be achieved through an embodiment of the present description which is illustrated in Figure 27. In the figure, a MAC PDU is shown in which a MAC control element and its associated subheader are placed at the beginning of the MAC PDU, the MAC subheader preceding the MAC control element with which it is associated (in the parsing direction which is here from the beginning of the MAC PDU towards the end). Specifically, the MAC control element shown in the figure is an enabling / disabling MAC CE. The enabling / disabling MAC CE precedes any MAC SDU and any MAC subheader associated with a MAC SDU. In the figure, two MAC SDUs and their subheaders are shown. Petition 870240080006, dated 09 / 19 / 2024, pp. 104 / 139 98 / 121 Associated MACs are shown. However, the embodiment of the description is not limited to the number of MAC SDUs being two. Alternatively, there may be only one MAC SDU or more than two MAC SDUs included in the MAC PDU. Although the MAC control element shown in the figure is an enable / disable CE, a contention resolution MAC CE and its associated subheader or the C-RNTI with its subheader may instead or in addition be placed at the beginning of a MAC SDU, i.e., before any MAC SDU and any MAC subheader associated with a MAC SDU. As shown in the figure, a MAC SDU in the present embodiment may end with a padding, if necessary. [000266] In other words, depending on the MAC CE type, the MAC CE is placed either before or after any MAC SDUs when mounting the MAC PDU. The MAC CE type can be defined in the respective MAC CE subheader, for example, within the LCID field. [000267] Different types of MAC CEs can be included in a MAC PDU, one type of which is advantageously placed at the beginning of the MAC PDU, i.e., before any MAC SDU, and another type is advantageously placed at the end of the MAC PDU, i.e., after any MAC SDU. Therefore, in an exemplary embodiment of the description, in addition to at least one second-layer control element which is placed after any second-layer SDU, the second-layer PDU also includes a second-layer control element which is placed before any second-layer SDU. A second-layer subheader associated with the second-layer control element placed before any second-layer SDU may also be included and placed before the respective second-layer control element at the beginning of the PDU. Petition 870240080006, dated 09 / 19 / 2024, pp. 105 / 139 99 / 121 second layer. [000268] An example of a MAC PDU format according to this embodiment is illustrated in Figure 33. At the beginning of the MAC PDU, there is a MAC CE, namely a C-RNTI MAC CE, which is preceded by the subheader associated with this C-RNTI MAC CE. After the C-RNTI MAC CE, two MAC SDUs are included in the MAC PDU, each of which is preceded by a respective associated MAC subheader. However, the description is not limited to the number of second-layer SDUs being two; there may be one or more than two second-layer control elements. After the last MAC SDU, an additional MAC CE is included and preceded by its respective associated MAC subheader. In the example shown in the figure, this MAC CE is a BSR MAC CE. However, the description is not limited to the MAC CE before any MAC SDU being a C-RNTI MAC CE, and the MAC CE after any MAC SDU being a BSR MAC CE.Instead of a C-RNTI, there could be, for example, an activation / deactivation MAC CE, and instead of a BSR MAC CE, there could be, for example, a PHR MAC control element. Furthermore, instead of a MAC CE placed before and a MAC CE placed after each MAC SDU, there could be two or more MAC CEs placed before and / or after any MAC SDU. Optionally, after the MAC CE placed after each MAC SDU, a padding is included at the end of the MAC PDU. This description is not limited to the ECs currently defined by LTE, but is also applicable to any CEs of any system. In general, CEs that require a longer calculation time or input from other layers can advantageously be placed at the end of the MAC PDU, while CEs that are available can be placed at the beginning of the MAC PDU. [000269] A MAC PDU format as shown in Figure 3 can advantageously be used in a transmitter / receiver system. Petition 870240080006, dated 09 / 19 / 2024, pp. 106 / 139 100 / 121 allows the transfer of parts of a TB instead of transferring only complete TBs to lower / upper layers. For example, the TB can be subdivided into a plurality of parts which become individual codewords and can also be provided for their respective CRCs. [000270] Thus, when the MAC PDU is divided between different parts of the TB and MAC CEs so that C-RNTI MAC CEs are placed at the beginning of the MAC PDU, these MAC CEs can be processed in the transmitter by the PHY layer within codewords without needing to wait for the completion and transfer of the entire TB. [000271] On the receiver side, one or more of the codewords can be received individually and their CRC can be verified. Then, the PHY can transfer the correctly received individual codewords to the MAC before the entire TB has been correctly received. This is advantageous, since the MAC CE located at the beginning of the MAC PDU (e.g., the C-RNTI) can be extracted at the MAC layer before the remaining TB codewords have been correctly received and passed to the MAC. However, if not all codewords belonging to the TB were received correctly, i.e., the TB was not successfully received, the entire TB is discarded, i.e., also the already parsed (pre-processed) parts such as MAC CEs and MAC SDUs. [000272] It is noted that the above layer processing is exemplary. The present description can also be applied to other system designs in which the transport block corresponds to a codeword and is not processed in multiple individual parts. [000273] Consequently, the receiver does not need to wait until the end of the TTI before it can process the respective MAC CE. Thus, Petition 870240080006, dated 09 / 19 / 2024, pp. 107 / 139 For the C-RNTI MAC CE (or another MAC CE such as an activation / deactivation MAC CE), preparation processing is possible. [000274] Thus, it may be advantageous if the data transmission and / or reception device is capable of generating and transmitting or receiving both the MAC CEs located before the MAC SDUs and the MAC CEs located after the MAC SDUs. It is noted that in general, the data transmission device may be the uplink terminal or the downlink base station. [000275] In one embodiment of the present description, a data transmission node for transmitting data over a wireless channel to a data reception node in a communication system may include a second-layer processing unit which is configurable to generate different types of second-layer PDUs. Specifically, it may be suitable for generating a first-type second-layer PDU which includes at least one second-layer SDU and at least one second-layer control element, or at least one second-layer control element following any of the at least one second-layer SDUs. This may further be configurable to generate a second-type PDU which includes at least one second-layer SDU and at least one second-layer control element, or at least one second-layer control element preceding any of the at least one second-layer SDUs. [000276] As discussed above, some MAC control elements are advantageously placed after any MAC SDUs in a MAC PDU, while other MAC control elements are advantageously placed before any MAC SDU. For this reason, one embodiment of the present description provides a second-layer processing unit which is configurable to generate a second-layer PDU that includes an element of Petition 870240080006, dated 09 / 19 / 2024, pp. 108 / 139 102 / 121 Type Switching Second Layer Control (Type Switching MAC CE) indicates whether the second-layer PDU that includes the type switching second-layer control element is a type-first second-layer SDU or a type-second second-layer SDU. The type switching second-layer control element precedes any second-layer SDU and any second-layer control element other than the type switching second-layer control element. The second-layer PDU also includes a second-layer subheader associated with and preceding the type switching second-layer control element. The second-layer subheader associated with the type switching second-layer control element precedes the type switching second-layer control element. However, it is noted that the explicit type switching MAC CE is only an example.Such MAC CE is not necessary to decide whether to generate a MAC PDU with the CEs at the beginning or at the end. This decision can be made solely based on the type of MAC CE(s) to be included in the MAC PDU according to some predefined (fixed) rules. [000277] Furthermore, it is noted that in general, a MAC PDU can also include both MAC CEs located before (any) MAC SDUs and MAC CEs located after any MAC SDUs. There may also be a difference between uplink and downlink. For example, in the downlink, MAC CEs can always be located at the beginning (i.e., preceding any SDUs) while in the uplink the MAC CE type determines whether it is mapped before or after the SDUs. [000278] In general, in a downlink, a data transmission node for transmitting data over a wireless channel to a data reception node in a communication system can be a base station. A data reception node for receiving data Petition 870240080006, dated 09 / 19 / 2024, pp. 109 / 139 103 / 121 on a wireless channel, a data transmission node in a downlink communication system can be a UE. As described above, for the uplink, the data transmission node can be a UE and the data reception node can be the base station (eNB). [000279] Generally, a UE and / or the base station may be able to operate as both a data transmission and data reception node. Specifically, the UE may be able to generate MAC PDUs with CEs placed after any SDUs as well as receive MAC PDUs with MAC CEs placed at the beginning of the MAC PDU. Similarly, the base station may be able to transmit MAC PDUs with CEs at the beginning and receive MAC PDUs with CEs at the end. However, it is noted that the present description is not limited to such combinations and both directions may support or be configurable to support either placing MAC CEs at the end or at the beginning of the MAC PDU, possibly depending on the type of MAC CEs. It is noted that in general, it is also possible to include MAC CEs at both ends of the MAC PDU, depending on its type. [000280] In the embodiments illustrated in Figures 23 to 27, MAC subheaders are placed respectively before the MAC SDU or the MAC control element to which they are associated. This arrangement of MAC subheaders in a MAC PDU allows the MAC subheaders to be processed as soon as possible by a receiver, provided that the MAC PDU is analyzed in the direction from beginning to end by the receiver (the direction pointing from left to right in Figures 23 to 30). However, in some cases, it may be advantageous to start the analysis of a MAC PDU starting from the end of the MAC PDU in the direction from beginning to beginning (in the figures from right to left). Specifically, when control elements are available at the end of a MAC PDU, they can be processed Petition 870240080006, dated 09 / 19 / 2024, pp. 110 / 139 104 / 121 previously in the receiver, if the MAC PDU is analyzed starting from the end. [000281] When a receiver analyzes a MAC PDU from its end (from back to front), a MAC subheader associated with a MAC control element can be processed earlier if it is placed after the respective control element (or, in other words, before the respective control element in the analysis direction).To achieve such advance processing of a MAC subheader associated with a MAC control element, an embodiment of the present description provides a data transmission that includes a second-layer processing unit to generate a second-layer PDU that includes at least one second-layer SDU and at least one second-layer control element and second-layer subheaders associated respectively with the second-layer SDU and the second-layer control element, wherein the at least one second-layer SDU is preceded by its respective associated subheader and the at least one second-layer control element is followed by its respective associated subheader. [000282] The format of such a second-layer PDU is illustrated in Figure 28. Specifically, the figure shows a MAC PDU that includes two MAC SDUs, MAC SDU1 and MAC SDU2. MAC SDU1 and MAC SDU2 are directly preceded by their respective associated subheader. The number of MAC SDUs shown in the figure is only exemplary. Alternatively, there may be one MAC SDU, three MAC SDUs, or more than three MAC SDUs included in the MAC PDU. The MAC PDU further includes two MAC control elements, MAC CE1 and MAC CE2, which follow each MAC SDU and each subheader associated with a MAC SDU, and subheaders of MACs respectively associated with these control elements. Petition 870240080006, dated 09 / 19 / 2024, pp. 111 / 139 105 / 121 MAC. A fill-in can also be included in the MAC PDU. [000283] However, if a receiver starts analyzing a MAC PDU at its end, the processing of MAC control elements and their associated subheaders is delayed when the padding is placed at the end of the MAC PDU, that is, after any MAC control element. Thus, instead of placing the padding at the end, it can be placed between the MAC SDUs with their associated subheaders and the MAC control elements and their associated subheaders. Such a location is also beneficial since when starting the analysis at the end of the PDU, the length of the padding is generally unknown so that analysis is not possible without obtaining the padding length information in some way (e.g., by signaling information). [000284] An example of this padding arrangement is shown in Figure 28, where the padding is directly preceded by MAC SDU2 and directly followed by MAC CE1. The subheader associated with MAC CE1 is placed after MAC CE1, and the subheader associated with MAC CE2 is placed after MAC CE2. This corresponds to a prepending of the subheader to the respective MAC CE in the direction of analysis, which is here reversed, i.e., from the end of the MAC PDU to the beginning, at least for all MAC CEs. It is noted that MAC SDUs can be analyzed in the usual (forward) direction from the beginning to the end of the MAC PDU. [000285] For example, the two MAC control elements could be either a BSR MAC control element or a PHR MAC control element. The description is not limited to MAC PDUs having two MAC control elements. Alternatively, there could be three or more MAC control elements or one MAC control element, which, for example, could be a BSR control element. Petition 870240080006, dated 09 / 19 / 2024, pp. 112 / 139 106 / 121 MAC or a PHR MAC control element. [000286] In order to analyze a MAC PDU in an efficient and time-saving manner, it is useful if the receiver can determine at an earlier analysis stage whether MAC control elements are available in the MAC PDU. Especially if the MAC CEs are located at the end of the MAC PDU, with such an indication, the receiver can begin analyzing the MAC CEs from the end of the MAC PDU backwards. Information on the availability of an additional MAC control element may be included in a MAC subheader. [000287] For this reason, in an exemplary embodiment, the first second-layer subheader comprised by the second-layer PDU, as previously discussed, includes a presence indicator that indicates whether the second-layer PDU includes at least one second-layer control element. [000288] Alternatively, all second-layer subheaders comprised by the second-layer PDU can include the presence indicator. This solution allows maintaining the subheader format independent of the SDU / CE position within the PDU. In this mode, it also conforms to the MAC subheader in the current LTE specifications. On the other hand, including the presence indicator only in the first MAC PDU subheader may be more efficient in terms of resource utilization. [000289] An example of such a presence indicator is shown in Figure 29. In the figure, a MAC PDU format is illustrated which is similar to the MAC PDU format shown in Figure 28. Consequently, at the beginning of the MAC PDU there is a MAC subheader associated with and preceding a MAC SDU, and at the end there is a MAC subheader associated with and following a MAC control element. For the MAC subheader at the beginning and the MAC subheader at the end of the MAC PDU, the structure of Petition 870240080006, dated 09 / 19 / 2024, pp. 113 / 139 Figure 107 / 121 further illustrates the MAC subheader. As already shown in Figure 25, MAC subheaders include a reserved bit (R), an F2 bit, an extension field (E), and an LCID. The settings for R, F2, E, and LCID are the same as those discussed in relation to Figure 25. The first MAC subheader, which is associated with a MAC SDU, also includes a second octet comprising an F field and an L field. This second octet is not shown for the last MAC subheader shown in the figure. It can be assumed that this MAC subheader is associated with a fixed-length MAC CE whose size is known based on the LCID, although the embodiment also includes the case of variable-length control elements in which a second octet and in some cases a third octet must be included in the MAC subheader. However, the first reserved bit is now used to indicate whether there are MAC control elements in the MAC PDU.Here it is assumed that if there are MAC CEs (at least one) in the MAC PDU, they are placed at the end. Consequently, the presence indicator can be used to instruct the receiver to analyze the MAC CEs (and their respective headers) from the end of the MAC PDU in the backward direction, i.e., from the end of the MAC PDU. Consequently, one of the R bits included in the MAC subheader at the beginning and / or all MAC PDU subheaders is set by the transmitter. [000290] For example, as shown in Figure 29, R = 1 means that MAC control elements are available in the MAC PDU and R = 0 means that no MAC control elements are available. In the figure, an R bit in both the first and last MAC subheader of the MAC PDU is shown to be set to R = 1, assuming that the remaining subheaders have the same format and the R field is also set (R = 1). However, the description Petition 870240080006, dated 09 / 19 / 2024, pp. 114 / 139 108 / 121 is not limited to a case where an R bit in all MAC subheaders is set to one. Alternatively, for example, only an R bit in the first MAC subheader can be set to indicate whether the MAC PDU includes a MAC control element. In other words, it is sufficient if the R field is present in the start subheader, i.e., the subheader which is analyzed first; however, this can also be set in all subheaders. [000291] In Figure 29, a case is shown in which the E bit in the last MAC subheader of the MAC PDU is set to 1. As discussed above regarding the MAC subheader structure, a value of E = 1 indicates that at least one more MAC subheader is present in the parsing direction. Since parsing starts from the end, the at least one additional MAC subheader can be identified with the MAC subheader associated with the MAC control element before the last MAC control element (which corresponds to the MAC control element CE1 in Figure 28). Thus, in this figure, the rightmost MAC subheader has the E field set to 1, meaning that the corresponding MAC CE is followed (in the backward parsing direction) by a second subheader associated with a second MAC CE. In the second subheader, the E field is set to 0 since in the backward parsing direction, there is no additional subheader, but instead only padding (optional). [000292] It is also noted that the analysis of the MAC PDU in Figure 29 at the receiver starts with the first subheader of the first SDU. Since R = 1, the analysis then advantageously continues from the end of the MAC PDU backwards as described above. After the MAC CEs are extracted, the analysis of the SDUs can be restarted from the beginning (left side of the figure). However, it is noted that this is only a Petition 870240080006, dated 09 / 19 / 2024, pp. 115 / 139 109 / 121 advantageous example of the analysis. The MAC PDU format also allows analysis of the SDUs first and then analysis of the MAC CEs from the end towards the beginning of the MAC PDU. [000293] Thus, the present description also provides a receiver that is capable of starting to analyze a MAC PDU from the beginning when no MAC control element is available, and from the end when at least one MAC control element is available. In one embodiment, a data receiving node includes a second-class processing unit to receive and analyze a second-layer PDU, wherein the second-layer processing unit analyzes the second-layer PDU starting from the end of the second-layer PDU when the presence indicator shows that at least one second-layer control element is included in the second-layer PDU. For example, the receiver's second-layer processing unit may be configured to analyze the second-layer PDU starting from the beginning by default. Thus, when it starts the analysis, it evaluates the presence indicator (such as a predefined R bit in the current LTE specification) in the first subheader.If the R bit has a value of R = 1, indicating that a MAC control element is included in the MAC PDU, it analyzes the MAC PDU from its end, deviating from the default setting. It is noted that using the reserved R bit is an advantageous option to provide a presence indicator to show if MAC CEs are present in the MAC PDU. However, this description is not limited to this, and the presence indicator can be introduced in another way, for example, by providing a longer MAC subheader. As also mentioned above, this description is not limited to the subheader format as defined by LTE. [000294] Alternatively, the second processing unit Petition 870240080006, dated 09 / 19 / 2024, pp. 116 / 139 Layer 110 / 121 can be configured to start MAC PDU analysis from the end by default. In this case, when it starts the analysis, it evaluates the MAC subheader at the end of the MAC PDU. When it evaluates the R bit in this subheader and detects the value of R = 1, indicating that there are MAC control elements in the MAC PDU, it continues to analyze the MAC PDU from the end. [000295] When the MAC PDU is parsed from the end, the individual octets of MAC subheaders and MAC control elements can be ordered in both directions. In other words, if the MAC PDU is parsed in the backward direction, the bit ordering within the individual MAC subheaders and MAC CEs which should be parsed in the backward direction may or may not also be reversed. However, the direction in which the receiver reads the individual MAC subheaders and MAC control elements must be known to the receiver. [000296] Thus, in one embodiment, a transmission node is described, which includes a second-layer processing unit to generate a second-layer PDU that includes at least one second-layer subheader and at least one second-layer control element, and subheaders associated respectively with at least one second-layer SDU and at least one second-layer control element, wherein the at least one second-layer SDU is preceded by its respective associated subheader and the at least one second-layer control element is followed by its respective associated subheader. [000297] The MAC PDU format shown in Figures 28 and 29 implies advantages that are associated with both the receiver and the transmitter. The receiver is able to analyze the end MAC PDU in order to quickly process MAC CEs if present. Petition 870240080006, dated 09 / 19 / 2024, pp. 117 / 139 111 / 121 [000298] The transmitter, on the other hand, has more processing time for computing MAC CEs since these are placed after any MAC SDUs. [000299] Another exemplary embodiment of the description is illustrated in Figure 30. The figure shows a PDU format in which the MAC control elements are placed after any MAC SDU, while the MAC subheaders associated with the MAC control elements are placed before any MAC SDU. Specifically, the MAC PDU illustrated in the figure includes two MAC SDUs, SDU1 and SDU2, both of which are preceded respectively by their associated subheaders. Furthermore, the MAC PDU includes two MAC control elements, each of which has a respective MAC subheader associated with it. However, instead of being placed directly before the associated MAC control elements, the MAC subheaders associated with the MAC control elements are placed before the MAC SDUs (all of which are within the MAC PDU) at the beginning of the MAC PDU.In other words, MAC SDUs and their associated subheaders are preceded by the MAC subheaders associated with the MAC control elements, but followed by the MAC control elements themselves, as MAC CEs are placed after any SDUs and their respective headers and, in this example, also after the padding. In the example shown in the figure, the MAC subheader for MAC CE1 precedes the MAC subheader for CE2, which in turn precedes MAC SDU 1, MAC SDU2, and the subheaders associated with the MAC SDUs. Furthermore, although the subheader for MAC CE1 precedes the subheader for MAC CE2, the MAC control element MAC1 follows the MAC control element MAC CE2. This has the advantage of efficient analysis at the receiver. The analysis begins from... Petition 870240080006, dated 09 / 19 / 2024, pp. 118 / 139 112 / 121 at the beginning of the MAC PDU, and thus, the subheader of a first MAC CE1 is read. Then, the parser can cut (extract) the corresponding MAC CE1 from the end of the MAC PDU immediately without waiting for further analysis. The analysis then continues with the next subheader belonging to a second MAC CE2. After analyzing this subheader, the second MAC CE2 can be cut from the end of the MAC PDU. Similarly, if there are no more than two MAC CEs, their subheaders are ordered sequentially at the beginning of the MAC PDU while the MAC CEs themselves are ordered from the end of the MAC PDU backwards in the same sequence. [000300] However, the description is not limited to this specific order. Alternatively, MAC subheaders associated with MAC control elements may be arranged in the same order as the MAC control elements with which they are associated. Furthermore, the modality is not limited to MAC SDUs that include two MAC SDUs and two MAC control elements; the numbers of MAC SDUs and MAC control elements may be different from two and different from each other. Padding is optionally included in the MAC PDU if some resources are left in a TB. In the figure, the padding is placed between the MAC SDUs and the MAC control elements, which allows parsing from both sides of the MAC PDU without requiring knowledge of the padding length. [000301] Note that the advantage of the present description is provided by the organization of the MAC PDU. The recipient should be able to analyze it to obtain the ECs and SDUs. The way in which the analysis is performed should not limit the present description. For example, even in the modality of Figure 30, the recipient can simply analyze the MAC PDU from beginning to end (from left to right in the figures). However, additional advantages can be achieved if the Petition 870240080006, dated 09 / 19 / 2024, pp. 119 / 139 113 / 121 receiver use the possibility of analyzing the MAC CEs first and then analyzing the remaining MAC PDU parts (SDUs, padding). [000302] Furthermore, the modality of Figure 30 does not require any presence indicator, since the MAC CE headers are ordered at the beginning of the MAC PDU so that the presence of the MAC CEs is indicated by the presence of the specific corresponding subheaders. [000303] In other words, according to one embodiment, each second-layer subheader associated with any of at least one second-layer control element precedes each second-layer SDU and the respective subheader associated with each second-layer SDU. At the same time, advantageously, the second-layer control elements are located after any second-layer SDUs. [000304] Thus, a receiver may be provided, from which the second-layer processing unit is configured to parse from the beginning of the second-layer PDU a subheader associated with a second-layer control element and extract from the second-layer PDU said second-layer control element placed after the second-layer SDU(s). [000305] In the subheaders, the LCIDs indicate whether the subheaders belong to MAC CEs or MAC SDUs. In a telecommunication system with a PDU structure as shown in Figure 30, the receiver analyzes the MAC PDU from the beginning. If a subheader belongs to a MAC CE, then the receiver retrieves the MAC CEs from the end of the MAC PDU, and if a subheader belongs to a MAC SDU, then it starts processing SDUs from the beginning. [000306] One advantage of this mode compared to the transmitter side is that the transmitter has more processing time. Petition 870240080006, dated 09 / 19 / 2024, pp. 120 / 139 114 / 121 for MAC CE computation since these are placed after any MAC SDUs. Furthermore, available MAC SDUs can be readily provided for PHY processing before the TB construction is complete. An advantage with respect to the receiver side is that the receiver can process MAC CEs quickly since the associated MAC headers are placed at the beginning of the TB. The MAC subheaders for BSR MAC CEs are advantageously placed after any MAC SDU, since the existence of a BSR is only known to the UE after the LCP has been finalized. [000307] As shown in Figure 30, MAC CEs can be located at the end of the MAC PDU. However, this is not necessarily the case if a filler CE is inserted into the MAC PDU. According to one embodiment, the second-layer PDU includes a temporary filler storage status report, BSR, and a second-layer subheader associated with the filler BSR, and the filler BSR and the second-layer subheader associated with the filler BSR are placed after any one of at least one second-layer SDU. [000308] Specifically, in LTE, a so-called filler BSR can be inserted into the MAC PDU. A filler BSR is a BSR that generally does not need to be included in the MAC PDU, as it is not the periodic or triggered BSR that is regularly or after triggering to be included in the MAC PDU. However, if the MAC PDU is mounted and there is still a portion of resources allocated to this MAC PDU free and large enough to accommodate a BSR, then a filler BSR is inserted into the MAC PDU. Such a filler BSR may have an LCID which is different from the LCIDs of non-filler LCIDs and Petition 870240080006, dated 09 / 19 / 2024, pp. 121 / 139 115 / 121 specifically may differ, for example, from the LCID values ​​specified for different types of BSRs in Table 6.2.1-2 in 3GPP TS 36.321 v 13.3.0. Thus, if a filler BSR is included in the MAC PDU, it would be included in Figure 30 after MAC CE1, that is, at the end of the MAC PDU along with its subheader.[000309] Also described, as shown in Figure 32, is a method for transmitting data over a wireless channel to a data receiving node in a communication system, comprising: receiving 3221t, from a third layer, at least one second-layer service data unit, SDU, to be mapped by over a resource allocated for data transmission, generating 3222t a second-layer protocol data unit, PDU, which includes said at least one second-layer SDU and at least one second-layer control element, the at least one second-layer control element placed after any of the at least one second-layer SDU, receiving 3271t the second-layer PDU generated by second-layer processing and mapping 3212t the second-layer PDU by over the resource allocated for data transmission. [000310] Furthermore, a method for transmitting data over a wireless channel to a data receiving node in a communication system is described which further comprises determining what type of second-layer control element should be included in the second-layer PDU, and, depending on the type of control element to be included, generating either a first-type second-layer PDU or a second-type second-layer PDU. Herein, a first-type second-layer PDU includes at least one second-layer SDU and at least one second-layer control element, the at least one second-layer control element placed after either of the at least one Petition 870240080006, dated 09 / 19 / 2024, pp. 122 / 139 116 / 121 A second-layer SDU, and a second-type PDU, includes at least one second-layer SDU and at least one second-layer control element, with at least one second-layer control element preceding any of the at least one second-layer SDU. [000311] Furthermore, a method for transmitting data over a wireless channel to a data receiving node in a communication system is described, in which the following steps are repeatedly applied in an alternating order: generating packets that constitute parts of the second-layer PDU, and transferring the packets that constitute parts of the second-layer PDU to the first-layer processing unit. Consequently, the packets that constitute parts of the second-layer PDU are transferred to the first-layer processing unit before the generation of the second-layer PDU is complete. Such packets may be respective single SDUs or a plurality of SDUs with their respective subheaders and / or respective MAC CEs with their associated headers. [000312] Also described, as shown in Figure 32, is a method for receiving data over a wireless channel from a data transmission node in a communication system, comprising: unmapping 3211r at least one second-layer protocol data unit, PDU, from a resource allocated for data reception, receiving 3222r and parsing 3222r the second-layer PDU unmapped by the first-layer processing unit, the second-layer PDU including at least one second-layer service data unit, SDU, and at least one second-layer control element, the at least one second-layer control element following any of the at least one second-layer SDU. Petition 870240080006, dated 09 / 19 / 2024, pp. 123 / 139 117 / 121 [000313] In one embodiment of the description, the method for receiving data includes the step of analyzing the second-layer PDU from the beginning of the second-layer PDU (that is, from the earlier received portion to the later received portion). [000314] In another embodiment, the method for receiving data includes the step of analyzing the second-layer PDU starting from the end of the second-layer PDU to each subheader associated with the second-layer CE, and each second-layer CE having been processed, and, after processing the second-layer CEs and the respective subheaders associated with the second-layer CEs, analyzing the remaining part of the second-layer PDU from the beginning, thereby processing the second-layer SDUs and the second-layer control elements associated with the second-layer SDUs.One advantage of this method is that the second-layer control elements are processed more quickly if the second-layer PDU has the format illustrated in Figures 28 and 29, where the second-layer CEs and the subheaders associated with the second-layer CEs are placed after any one of the at least one second-layer SDUs, and no padding is placed after the second-layer CEs and the subheaders associated with the second-layer CEs. [000315] For example, when the first or any second-layer subheader includes a presence indicator that shows whether the second-layer PDU includes at least one second-layer control element, the method for receiving data may include the step of parsing the second-layer PDU starting from the end of the second-layer PDU. An example of such a presence indicator is the R bit in the MAC subheader associated with the first MAC SDU in the MAC PDU of Figure 29. Consequently, after evaluating this R bit, if R = 1, the step of parsing the second-layer PDU follows. Petition 870240080006, dated 09 / 19 / 2024, pp. 124 / 139 118 / 121 layer of the second-layer PDU final, thus evaluating the MAC control elements and the MAC subheader associated with the MAC control elements. [000316] Alternatively, in an exemplary embodiment, the method for receiving data includes the steps of parsing from the beginning of the second-layer PDU a subheader associated with a second-layer control element, and extracting from the second-layer PDU said second-layer control element placed after any second-layer SDUs. For example, this method is applicable to a second-layer PDU that has the format shown in Figure 30. The steps of parsing from the beginning of the second-layer PDU a second-layer subheader associated with a second-layer control element and extracting (cutting) the respective second-layer control element can alternate until all second-layer control elements have been extracted.Subsequently, you can proceed to the next step of analyzing the remaining part of the second-layer PDU from the beginning, thereby analyzing at least one second-layer SDU and second-layer subheader(s) respectively associated with at least one second-layer SDU. Hardware and Software Implementation as Description Presents [000317] Other exemplary embodiments refer to the implementation of the various embodiments described above using hardware and software. In this connection, a user terminal (mobile terminal) and an eNodeB (base station) are provided. The user terminal and the base station are adapted to execute the methods described herein, including corresponding entities to participate appropriately in the methods, such as receiver, transmitter, processors. [000318] It is also recognized that the various modalities can be Petition 870240080006, dated 09 / 19 / 2024, pp. 125 / 139 119 / 121 implemented or executed using computing devices (processors). A computing device or processor can be, for example, general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, etc. These may include a data input and output coupled to them. The various modalities may also be executed or incorporated by a combination of these devices. [000319] Furthermore, the various modalities may also be implemented by means of software modules, which are executed by a processor or directly in hardware. A combination of software modules and a hardware implementation may also be possible.Software modules can be stored on any type of computer-readable storage medium, for example, RAM, EPROM, EEPROM, flash memory, registers, hard drives, CD-ROM, DVD, etc. [000320] It should also be noted that the individual characteristics of the different modalities may individually or in arbitrary combination be the subject of another modality. [000321] It will be appreciated by a person skilled in the art that numerous variations and / or modifications can be made to the present description as shown in the specific embodiments. The present embodiments should therefore be considered in all respects to be illustrative and not restrictive. [000322] In summary, the present description refers to layer processing in a receiver and a transmitter in a communication system. Layer processing includes at least one processing on a first, second, and third layer. On the transmitter side, the third layer receives Petition 870240080006, dated 09 / 19 / 2024, pp. 126 / 139 120 / 121 a packet, adds its header and transfers the packet to the second layer. The second layer performs segmentation and provides segmented data to the first layer, which maps the segmented data onto physical resources. Segmentation is based on allocated resources. A retransmission can occur in the third layer, and thus, the third layer can re-segment the packet according to the received return to specific segments and provide the re-segmented data to the lower layers. Alternatively, the return information is provided to the second layer, which then performs segmentation taking it into account. Correspondingly, the receiver performs reordering and reassembly in the third layer, for which it also receives control information from the second layer. [000323] Furthermore, the present description refers to systems and methods for transmitting data over a wireless channel from a data transmission node to a data reception node in a communication system.Specifically, the data transmission node comprises a second-layer processing unit to receive, from a third layer, at least one second-layer service data unit, SDU, to be mapped onto a resource allocated for data transmission, and to generate a second-layer protocol data unit, PDU, which includes said at least one second-layer SDU and at least one second-layer control element, the at least one second-layer control element placed after any of the at least one second-layer SDU, and a first-layer processing unit to receive the second-layer PDU generated by the second-layer processing unit and map the second-layer PDU onto the resource allocated for data transmission. The receiving node of... Petition 870240080006, dated 09 / 19 / 2024, pp. 127 / 139 121 / 121 data comprises a first-layer processing unit for unmapping at least one second-layer protocol data unit, PDU, from a resource allocated for data reception, and a second-layer processing unit for receiving and parsing the second-layer PDU unmapped by the first-layer processing unit, the second-layer PDU including at least one second-layer service data unit, SDU, and at least one second-layer control element, the at least one second-layer control element following any of the at least one second-layer SDU.

Claims

1. Data transmission node (3100t) for transmitting data through a wireless channel (3190) to a data reception node (3100r) in a communication system (3100), characterized in that it comprises: a second-layer processing circuit (3120t), which, in operation, receives from a third layer (3130t) at least one second-layer service data unit (SDU) (243a) to be mapped onto a resource allocated for data transmission, and generates a second-layer protocol data unit (PDU) (2400) including at least one second-layer SDU (243a) and at least one second-layer control element (244a), the at least one second-layer control element (244a) placed after any one of the at least one second-layer SDU (243a), a first-layer processing circuit (3110t), which, in operation,receives the second-layer PDU (2400) generated by the second-layer processing circuit (3120t) and maps the second-layer PDU (2400) to the resource allocated for data transmission, wherein the second-layer PDU (2400) includes a temporary padding storage status report, BSR, and a second-layer subheader associated with the padding BSR, and the padding BSR and the second-layer subheader associated with the padding BSR are placed after any one of at least one second-layer SDU (243a).

2. Data transmission node according to claim 1, characterized in that the second-layer control element is a Medium Access Control, MAC, control element, and the second-layer PDU further includes: a respective second-layer subheader (241a) associated with each of at least one second-layer SDU (243a), and a respective second-layer subheader (242a) associated with each of at least one second-layer control element (244a).

3. Data transmission node according to claim 2, characterized in that at least one second-layer SDU (243a) is placed after its associated subheader (241a) and at least one second-layer control element (244a) is placed before its associated subheader (242a).

4. Data transmission node (3100t) according to claim 3, characterized in that either the first or each second-layer subheader (241a) includes a presence indicator indicating whether the second-layer PDU (2400) includes at least one second-layer control element (244a).

5. Data transmission node (3100t) according to claim 2, characterized in that each second-layer subheader (242a) associated with any one of at least one second-layer control element (244a) precedes each second-layer SDU (243a) and the respective subheader (241a) associated with each second-layer SDU (243a).

6. Data transmission node (3100t) according to claim 1, characterized in that a type-first second-layer PDU (2400) includes at least one type-second SDU (243a) and at least one type-second control element (244a), the at least one type-second control element placed after any of the at least one type-second SDU (243a); a type-second PDU includes at least one type-second SDU and at least one type-second control element, the at least one type-second control element preceding any of the at least one type-second SDU; and the type-second processing circuit (3120t) is further configurable to generate a type-second second-layer PDU.

7. Data transmission node (3100t) according to claim 6, characterized in that the second-layer processing circuit (3120t) is configurable to generate, depending on the type of second-layer control element (244a) to be included in the second-layer PDU, either a first-type second-layer PDU (2400) or a second-type second-layer PDU.

8. Data transmission node (3100t) according to any one of claims 1 to 7, characterized in that the second-layer processing circuit (3120t) is configured to initiate forwarding of packets that constitute parts of the second-layer PDU (2400) to the first-layer processing circuit before the generation of the second-layer PDU (2400) is completed.

9. Data receiving node (3100r) for receiving data through a wireless channel (3190) from a data transmitting node (3100t) in a communication system (3100), characterized in that it comprises: first-layer processing circuit (3110r), Petition 870240080006, dated 09 / 19 / 2024, p. 131 / 139 4 / 7 that, in operation, unmaps at least one second-layer protocol data unit, PDU (2400), from a resource allocated for data reception, second-layer processing circuit (3120r), which, in operation, receives and analyzes the second-layer PDU (2400) unmapped by the first-layer processing circuit (3110r), the second-layer PDU (2400) including at least one second-layer service data unit, SDU (243a), and at least one second-layer control element (244a), the at least one second-layer control element (244a) following any one of the at least one second-layer SDU (243a),wherein the second-layer PDU (2400) includes a temporary fill storage status report, BSR, and a second-layer subheader associated with the fill BSR, and the fill BSR and the second-layer subheader associated with the fill BSR are placed after any one of at least one second-layer SDU (243a).

10. Data receiving node according to claim 9, characterized in that the second-layer control element is a Medium Access Control, MAC, element, a corresponding second-layer subheader (241a) is associated with each of at least one second-layer SDU (243a), and a corresponding second-layer subheader (242a) is associated with each of at least one second-layer control element (244a). Petition 870240080006, dated 09 / 19 / 2024, pp. 132 / 139 5 / 7 11. Data receiving node (3100r) according to claim 10, characterized in that the first or each second-layer subheader (241a) includes a presence indicator indicating whether the second-layer PDU (2400) includes at least one second-layer control element (244a), and when the presence indicator indicates that at least one second-layer control element (244a) is included in the second-layer PDU (2400), the second-layer processing circuit (3120r) analyzes the second-layer PDU (2400) starting from the end of the second-layer PDU (2400).

12. Data receiving node (3100r) according to claim 10, characterized in that the second-layer processing circuit (3120r) is configured to parse from the beginning of the second-layer PDU (2400) a subheader (242a) associated with a second-layer control element (244a) and to extract from the second-layer PDU (2400) said second-layer control element (244a) placed after any second-layer SDUs (243a).

13. Method for transmitting data through a wireless channel (3190) to a data receiving node (3100r) in a communication system (3100), characterized in that it comprises: receiving (3221t), from a third layer (3130t), at least one second-layer service data unit, SDU (243a) to be mapped onto a resource allocated for data transmission, generating (3222t) a second-layer protocol data unit, PDU (2400) including at least one second-layer SDU (243a) and at least one second-layer control element (244a), or at least one second-layer control element. Petition 870240080006, dated 09 / 19 / 2024, page.133 / 139 6 / 7 layer (244a) placed after any one of at least one second layer SDU (243a), receive (3211t) the second layer PDU (2400) generated by the second layer processing circuit (3120t) and map (3212t) the second layer PDU (2400) to the resource allocated for data transmission, wherein the second layer PDU (2400) includes a temporary padding storage status report, BSR, and a second layer subheader associated with the padding BSR, and the padding BSR and the second layer subheader associated with the padding BSR are placed after any one of at least one second layer SDU (243a).

14. Method for receiving data through a wireless channel (3190) from a data transmission node (3100t) in a communication system (3100), characterized in that it comprises: unmapping (3211r), by first-layer processing, at least one second-layer protocol data unit (PDU) (2400) from a resource allocated for data reception, receiving (3221t) and parsing (3222t) the second-layer PDU (2400) unmapped by first-layer processing, the second-layer PDU (2400) including at least one second-layer service data unit (SDU) (243a) and at least one second-layer control element (244a), the at least one second-layer control element (244a) following any one of the at least one second-layer SDU (243a), Petition 870240080006, of 19 / 09 / 2024, page.134 / 139 7 / 7 a second-layer PDU (2400) includes a temporary fill storage status report, BSR, and a second-layer subheader associated with the fill BSR, and the fill BSR and the second-layer subheader associated with the fill BSR are placed after any one of at least one second-layer SDU (243a).

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