Vehicle mobile device and radio base station

Abstract

The invention relates to a vehicular mobile device. The vehicular device comprises a transmitter that transmits assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes to a radio base station; a receiver that receives, from the radio base station, a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations being configured to be usable in at least one of the D2D data transmissions, and receives, from the radio base station, an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically assign radio resources for each of the D2D data transmissions for the vehicular mobile device; and the transmitter performs one or more D2D data transmissions based on the radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

Description

[0001] This application is a divisional application of the application patent application with the application date of 1 April 2016, the application number: 201680083840.6, and the invention name: "Improved semi-persistent resource allocation for V2V traffic". TECHNICAL FIELD

[0002] The present disclosure relates to improved semi-persistent resource allocation between a mobile terminal and a radio base station. The present disclosure provides a corresponding (vehicular) mobile terminal and radio base station. BACKGROUND

[0003] Long Term Evolution (LTE)

[0004] Third generation mobile systems (3G) based on the WCDMA radio access technology are being deployed worldwide. The first step to enhance or evolve this technology requires the introduction of High Speed Downlink Packet Access (HSDPA) and Enhanced Uplink (also known as High Speed Uplink Packet Access (HSUPA)), giving a radio access technology with a high competitiveness.

[0005] To be prepared for further growth in user needs and to be competitive with respect to new radio access technologies, 3GPP introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to meet the carrier needs for high speed data and media transmission as well as large capacity voice support in the next decade. The ability to provide high bit rates is a key measure of LTE.

[0006] The Work Item (WI) specification for Long Term Evolution (LTE) of the Evolved UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN) was finalized as Release 8 (LTE Release 8). The LTE system represents a highly efficient, packet-based, radio access and radio access network that provides full IP-based functionality with low latency and low cost. In LTE, multiple transmission bandwidths, such as 1.4, 3.0, 5.0, 10.0, 15.0 and 20.0 MHz, are specified to enable flexible system deployment using a given spectrum. In the downlink, an Orthogonal Frequency Division Multiplexing (OFDM) based radio access is employed because of its inherent resistance to Multi-Path Interference (MPI) due to low symbol rates, use of a cyclic prefix (CP) and its association with different transmission bandwidth arrangements. In the uplink, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) based radio access is employed because, given the limited transmit power of user equipment (UE), wide area coverage is prioritized over increasing peak data rates. A number of key packet radio access technologies, including Multiple Input Multiple Output (MIMO) channel transmission techniques, are employed and an efficient control signaling structure is implemented in LTE Release 8 / 9.

[0007] LTE Architecture

[0008] Figure 1 The overall LTE architecture is shown in Figure 1. The E-UTRAN includes the eNode B, which provides the E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocol terminations towards the user equipment (UE). The eNode B (eNB) hosts the Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Control Protocol (PDCP) layers which include the functionality for header compression, ciphering / deciphering, and handover between the different radio access technologies. The eNode B also provides Radio Resource Control (RRC) functionality, which includes load management, admission control, scheduling, and enforcement of negotiated uplink QoS, cell information broadcast, and encryption / decryption of user and control plane data. The eNode Bs are interconnected with each other by the X2 interface.

[0009] The eNodeB is also connected by means of an S1 interface to the EPC (Evolved Packet Core), more specifically to the MME by means of the S1-MME (S1 -MME) interface and to the Serving Gateway (SGW) by means of the S1-U interface. The S1 interface supports a many-to-many relation between MMEs / Serving Gateways and eNodeBs. The SGW routes and forwards user data packets, while also acting as the mobility anchor for the user plane during inter-eNodeB handovers and as the anchor for user plane mobility between LTE and other 3GPP technologies (terminating S4 interface and relaying the traffic between the 2G / 3G systems and the PDN GW). For idle mode user equipments, the SGW terminates the downlink data path and triggers paging when downlink data arrives for the user equipment. It also manages and stores user equipment contexts, such as parameters for IP bearer service, network internal routing information. In case of lawful interception, the SGW also performs replication of user traffic.

[0010] The MME is the key control-node for the LTE access-network. It is responsible for idle mode user equipment tracking and paging procedure including retransmissions. It is also responsible for activating / deactivating user equipment bearers, and is also in charge of choosing the SGW for a user equipment at initial attach and at time of intra-LTE handover involving CN node relocation. It is responsible for authenticating the user (by interacting with the HSS). Non-access stratum (NAS) signaling terminates at the MME and it also is responsible for generation and allocation of temporary identities to user equipments. It checks the authorization of user equipments to camp on the service provider's public land mobile network (PLMN) and enforces user equipment roaming restrictions. The MME is the termination point in the network for ciphering / integrity protection for NAS signaling and handles the security key management. Lawful interception of signaling is also supported by the MME. The MME also provides the control plane function for the signaling between the user equipment and the PDN gateway. It also terminates the S3 interface towards the home HSS for roaming user equipments. Finally, the MME is responsible for the distribution of paging messages to the eNodeBs and for the MME-initiated paging of user equipments.

[0011] Component carrier structure in LTE

[0012] In the time-frequency domain, the downlink component carrier of the 3GPP LTE system is subdivided in so-called subframes. In 3GPP LTE, each subframe is divided as follows Figure 2The first downlink slot of the two downlink slots shown in the middle includes a control channel region (PDCCH region) within the first OFDM symbol. Each subframe includes a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8)), each OFDM symbol spanning the entire bandwidth of the component carrier. Thus, each OFDM symbol includes a plurality of modulation symbols transmitted on a respective subcarrier. In LTE, the transmitted signal in each time slot is described by a resource grid of subcarriers and OFDM symbols. is the number of resource blocks within the bandwidth. The quantity depends on the configured downlink transmission bandwidth in the cell, and shall satisfy where and are the minimum and maximum downlink bandwidths supported by the current release of the specification, respectively. is the number of subcarriers within a resource block. For a normal cyclic prefix OFDM symbol structure, and

[0013] Assuming a multi-carrier communication system employing OFDM, such as used in 3GPP Long Term Evolution (LTE), for example, the smallest unit of resources that can be allocated by a scheduling unit is a "resource block". A physical resource block (PRB) is defined as a contiguous OFDM symbol (e.g., 7 OFDM symbols) in the time domain and a contiguous subcarrier in the frequency domain, as exemplified in Figure 2 (e.g., 12 subcarriers for a component carrier). In 3GPP LTE (Release 8), a physical resource block thus comprises a resource unit corresponding to one time slot in the time domain and 180 kHz in the frequency domain (for further details on the downlink resource grid, see, e.g., 3GPP TS 36.211, "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)", current version 13.0.0, section 6.2, which is available at http: / / www.3gpp.org and incorporated herein by reference).

[0014] A subframe includes two slots, so that 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 an "extended" CP is used. For terminology, a time-frequency resource spanning the same contiguous subcarriers across a complete subframe is referred to as a "resource block pair", or equivalently "RB pair" or "PRB pair".

[0015] The term "component carrier" refers to a combination of several resource blocks in the frequency domain. In future releases of LTE, the term "component carrier" is no longer used; instead, the term is changed to "cell", which refers to a combination of downlink and optionally uplink resources. The association between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources is indicated in system messages transmitted on the downlink resources.

[0016] Similar assumptions for component carrier structures will also apply to later releases.

[0017] Carrier aggregation in LTE-A for supporting wider bandwidths

[0018] The spectrum for IMT-Advanced was decided at the World Radio Communication Conference 2007 (WRC-07). Although the overall spectrum for IMT-Advanced was decided, the actual available frequency bandwidths differ from region to region or country to country. However, after the outline of the available spectrum was decided, the 3rd Generation Partnership Project (3GPP) started the standardization of the radio interface. At the 3GPP TSG RAN #39 meeting, a study item description on "Further Advancements for E-UTRA (LTE-Advanced)" was approved. This study item covers technical parts to be considered for the evolution of E-UTRA, e.g., to meet the requirements of IMT-Advanced.

[0019] The bandwidth that can be supported by LTE-Advanced systems is 100 MHz, while LTE systems can only support 20 MHz. Now, the lack of radio spectrum is a bottleneck for the development of wireless networks, and therefore, it is difficult to find a spectrum band wide enough for LTE-Advanced systems. Thus, there is an urgent need to find a way to obtain a wider radio spectrum band, and the possible answer is the carrier aggregation functionality.

[0020] In carrier aggregation, two or more component carriers are aggregated in order to support a wider transmission bandwidth of up to 100 MHz. Several cells in LTE systems are aggregated into a wider channel in LTE-Advanced systems that is wide enough for 100 MHz, even if these cells in LTE can be in different frequency bands.

[0021] All component carriers can be LTE Release 8 / 9 compatible, at least when the bandwidth of the component carrier does not exceed the bandwidth supported by a Release 8 / 9 cell. Not all component carriers aggregated by a user equipment have to be LTE Release 8 / 9 compatible. Existing mechanisms, e.g., barring, can be used to avoid that Release 8 / 9 user equipments camp on a component carrier.

[0022] A user equipment can simultaneously receive or transmit on one or multiple component carriers (corresponding to multiple serving cells) depending on its capabilities. LTE-A Release 10 user equipments with reception and / or transmission capabilities for carrier aggregation can simultaneously receive and / or transmit on multiple serving cells, while LTE Release 8 / 9 user equipments can only receive and transmit on a single serving cell, provided that the structure of the component carriers follows the Release 8 / 9 specifications.

[0023] The carrier aggregation is supported for both contiguous and non-contiguous component carriers, with each component carrier limited to a maximum of 110 resource blocks in the frequency domain (using 3GPP LTE (Release 8 / 9) numerology).

[0024] A 3GPP LTE-A (Release 10) compatible user equipment can be configured to aggregate a different number of component carriers originating from the same eNodeB (base station) and possibly with different bandwidths in the uplink and downlink. The number of configurable downlink component carriers depends on the downlink aggregation capability of the UE. Conversely, the number of configurable uplink component carriers depends on the uplink aggregation capability of the UE. It can currently not be possible to configure a mobile terminal with more uplink component carriers than downlink component carriers. In a typical TDD deployment, the number of component carriers and the bandwidth of each component carrier is the same in the uplink and downlink. The component carriers originating from the same eNodeB do not need to provide the same coverage.

[0025] The spacing between the center frequencies of the contiguous aggregated component carriers should be a multiple of 300 kHz. This is to be compatible with the 100 kHz frequency raster of 3GPP LTE (Release 8 / 9) while preserving the orthogonality of subcarriers with a 15 kHz spacing. Depending on the aggregation scenario, the n x 300 kHz spacing can be facilitated by inserting a small number of unused subcarriers between contiguous component carriers.

[0026] The nature of the aggregation of multiple carriers is only exposed upwards to the MAC layer. For both the uplink and the downlink, one HARQ entity is needed in the MAC for each aggregated component carrier. There is at most one transport block per component carrier (in the absence of SU-MIMO for the uplink). The transport block and its potential HARQ retransmissions need to be mapped onto the same component carrier.

[0027] When a carrier aggregation is configured, the mobile terminal has only one RRC connection with the network. At RRC connection setup / reestablishment, one cell provides the security input (one ECGI, one PCI, and one ARFCN) and non-access stratum mobility information (e.g., TAI), similarly as in LTE Release 8 / 9. After RRC connection setup / reestablishment, the component carrier corresponding to this cell is called the downlink primary cell (PCell). For a user equipment in each connected state, one and only one downlink PCell (DL PCell) and one uplink PCell (UL PCell) are always configured. Within the set of configured component carriers, other cells are called secondary cells (SCells); the carriers of SCells are downlink secondary component carriers (DL SCCs) and uplink secondary component carriers (UL SCCs). A maximum of five serving cells, including the PCell, can be configured for one UE.

[0028] MAC layer / entity, RRC layer, physical layer

[0029] The LTE Layer 2 user plane / control plane protocol stack includes four sub-layers, namely, RRC, PDCP, RLC, and MAC. The medium access control (MAC) layer is the lowest sub-layer in the Layer 2 architecture of the LTE radio protocol stack and is defined by, for example, the current Release 13.0.0 of the 3GPP technical standard TS 36.321. The connection to the physical layer below is through transport channels, and the connection to the RLC layer above is through logical channels. Thus, the MAC layer performs multiplexing and demultiplexing between logical channels and transport channels: the MAC layer in the transmitting side constructs MAC PDUs (called transport blocks) from MAC SDUs received through logical channels, and the MAC layer in the receiving side recovers MAC SDUs from MAC PDUs received through transport channels.

[0030] The MAC layer provides a data transfer service for the RLC layer through logical channels, which are either control logical channels carrying control data (e.g., RRC signaling) or traffic logical channels carrying user plane data (see subclauses 5.4 and 5.3 of TS 36.321 incorporated by reference herein). On the other hand, data from the MAC layer is exchanged with the physical layer through transport channels, which are classified as downlink or uplink. Data is multiplexed into transport channels according to how it is transmitted over the air.

[0031] The physical layer is responsible for the actual transmission of data and control information over the air interface, i.e. the physical layer carries all information from the MAC transport channels over the air interface on the transmitting side. Some of the important functions performed by the physical layer include coding and modulation, link adaptation (AMC), power control, cell search (for initial synchronization and handover purposes) and other measurements for the RRC layer (within the LTE system and between systems). The physical layer performs transmission based on transmission parameters such as modulation scheme, coding rate (i.e. modulation and coding scheme, MCS), number of physical resource blocks, etc. More information on the role of the physical layer can be found in the current version 13.0.0 of the 3GPP technical standard 36.213, incorporated herein by reference.

[0032] The radio resource control (RRC) layer controls the communication between the UE and the eNB at the radio interface and the mobility of the UE moving across several cells. The RRC protocol also supports the transfer of NAS information. For UEs in RRC IDLE, RRC supports notification of incoming calls from the network. The RRC connection control covers all procedures related to the establishment, modification and release of an RRC connection, including paging, measurement configuration and reporting, radio resource configuration, initial security activation, and establishment of signaling radio bearers (SRBs) and radio bearers carrying user data (data radio bearers, DRBs).

[0033] The radio link control (RLC) sublayer mainly includes ARQ functionality and supports data segmentation and concatenation, i.e. the RLC layer performs framing of RLC SDUs to put them in sizes indicated by the MAC layer. The latter two minimize the protocol overhead independently of the data rate. The RLC layer is connected to the MAC layer via logical channels. Each logical channel transports a different type of traffic. The layer above the RLC layer is usually the PDCP layer, but in some cases the layer above the RLC layer is the RRC layer, i.e. RRC messages sent on the logical channels BCCH (broadcast control channel), PCCH (paging control channel) and CCCH (common control channel) do not require security protection and therefore bypass the PDCP layer and go directly to the RLC layer. The main services and functions of the RLC sublayer include:

[0034] • Transfer of upper layer PDUs for AM, UM or TM data transfer;

[0035] • Error correction by ARQ;

[0036] • Segmentation according to the size of the TB;

[0037] • Re-segmentation if necessary (e.g. when the radio quality, i.e. the supported TB size, changes)

[0038] • Concatenation of SDUs for the same radio bearer is FFS;

[0039] • In-sequence delivery of upper layer PDUs;

[0040] • Duplicate detection;

[0041] • Protocol error detection and recovery;

[0042] • SDU discard;

[0043] • Reset

[0044] The ARQ functionality provided by the RLC layer will be discussed in more detail in a later section.

[0045] Uplink access scheme for LTE

[0046] For uplink transmission, high-efficiency user terminal transmissions are required to maximize the coverage. Single-carrier transmission combined with FDMA with dynamic bandwidth allocation has been chosen as the evolved UTRA uplink transmission scheme. The main reason for preferring single-carrier transmission is the lower peak-to-average power ratio (PAPR) compared to multi-carrier signals (OFDMA) and the corresponding improved power amplifier efficiency and improved coverage (higher data rates for a given terminal peak power). During each time interval, the eNodeB allocates a unique time / frequency resource to the user for transmitting user data, thereby ensuring intra-cell orthogonality. Orthogonal access in the uplink ensures a spectral efficiency improvement by eliminating intra-cell interference. Interference due to multipath propagation is helped by inserting a cyclic prefix in the transmitted signal at the base station (eNodeB).

[0047] The basic physical resource for data transmission comprises a frequency resource of size BWgrantduring one time interval (e.g., a subframe) onto which the coded information bits are mapped. It should be noted that a subframe (also referred to as a transmission time interval (TTI)) is the smallest time interval for user data transmission. However, frequency resources BWgrantover time periods longer than one TTI can be allocated to a user by concatenating subframes.

[0048] Layer 1 / Layer 2 control signaling

[0049] In order to inform the scheduled users about their allocation status, transmission format and other transmission related information (e.g. HARQ information, Transmit Power Control (TPC) commands), L1 / L2 control signaling is transmitted on the downlink together with the data. Assuming that the user allocation can change from subframe to subframe, the L1 / L2 control signaling is multiplexed with the downlink data in a subframe. It should be noted that the user allocation can also be performed on a TTI (Transmission Time Interval) basis, the TTI length can be a multiple of a subframe. The TTI length can be fixed in the service area for all users, can be different for different users, or can even be dynamic for each user. Generally, the L1 / L2 control signaling only needs to be transmitted once per TTI. Without loss of generality, the following assumes that a TTI corresponds to one subframe.

[0050] The L1 / L2 control signaling is transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries messages as Downlink Control Information (DCI), which in most cases includes resource allocation and other control information for a group of mobile terminals or UEs. Several PDCCHs can be transmitted in one subframe.

[0051] Generally, the information transmitted in the L1 / L2 control signaling for allocating uplink or downlink radio resources (especially LTE(-A) Release 10) can be categorized as follows:

[0052] - User identity , which indicates the allocated users. This is usually included in the checksum by masking the CRC with the user identity;

[0053] - Resource allocation information , which indicates the resources (e.g. Resource Blocks, RBs) allocated to the users. Alternatively, this information is referred to as Resource Block Allocation (RBA). Note that the number of RBs allocated to a user can be dynamic;

[0054] - Carrier indicator , which is used in case of cross-carrier scheduling, where the control channel transmitted on a first carrier allocates resources on a second carrier (i.e. resources on the second carrier or resources related to the second carrier);

[0055] - Modulation and coding scheme , which determines the modulation scheme and coding rate used;

[0056] - HARQ information , such as the New Data Indicator (NDI) and / or the Redundancy Version (RV), which is especially useful in retransmissions of data packets or parts thereof;

[0057] - Power control command , which is used to adjust the transmit power of the allocated uplink data or control information transmission;

[0058] - Reference signal information such as the applied cyclic shift and / or orthogonal cover code index to be used for the transmission or reception of reference signals related to the allocation;

[0059] - Uplink or downlink assignment index for identifying the allocation order, which is particularly useful in TDD systems;

[0060] - Hopping information for example, an indication of whether and how resource hopping is applied in order to increase frequency diversity;

[0061] - CSI request for triggering the transmission of channel state information in the allocated resources; and

[0062] - Multi-cluster information which is a flag for indicating and controlling whether the transmission takes place in a single cluster (a contiguous set of RBs) or in multiple clusters (at least two non-contiguous sets of contiguous RBs). Multiple cluster allocation has been introduced by 3GPP LTE-(A) Release 10.

[0063] It should be noted that the above list is non-exhaustive and that not all of the mentioned information items need to be present in each PDCCH transmission, depending on the used DCI format.

[0064] Downlink control information comes in several formats, which differ in their overall size as well as in the information contained in their fields, as described above. The different DCI formats currently defined for LTE are as follows and are described in detail in 3GPP TS 36.212 "Multiplexing and channel coding", section 5.3.3.1 (current version v.13.0.0 is available at http: / / www.3gpp.org and hereby incorporated by reference). For further information on the relevant DCI formats and the specific information transmitted in the DCI, see the mentioned technical standard, or "LTE - The UMTS Long Term Evolution - From Theory to Practice", edited by Stefanie Sesia, Issam Toufik, Matthew Baker, chapter 9.3 (incorporated by reference here). For example, the following DCI formats can be used for carrying resource grants for the uplink.

[0065] - Format 0: DCI format 0 is used for transmitting resource grants for PUSCH using single antenna port transmission in uplink transmission mode 1 or 2.

[0066] - Format 4: DCI format 4 is used to schedule PUSCH with closed loop spatial multiplexing transmission in uplink mode 2.

[0067] The current version 13.0.0 of the 3GPP technical standard TS 36.212 defines in subclause 5.4.3 control information for sidelink, which is incorporated herein by reference.

[0068] Semi-Persistent Scheduling (SPS)

[0069] In downlink and uplink, the scheduling eNodeB dynamically assigns resources to user equipments via L1 / L2 control channels (PDCCH) at every transmission time interval, where the user equipment is addressed via its C-RNTI. As previously mentioned, the CRC of the PDCCH is masked with the C-RNTI of the addressed user equipment (so-called dynamic PDCCH). Only the user equipment with the matching C-RNTI can correctly decode the PDCCH content, i.e. the CRC check is positive. Such PDCCH signaling is also referred to as dynamic (scheduling) grant. The user equipment monitors the L1 / L2 control channel for dynamic grants at every transmission time interval in order to find possible assignments (downlink and uplink) that can be allocated to it.

[0070] Furthermore, the E-UTRAN can persistently assign uplink / downlink resources for initial HARQ transmissions. When needed, retransmissions are explicitly signaled via L1 / L2 control channels. Since the retransmissions are dynamically scheduled, such operation is referred to as semi-persistent scheduling (SPS), i.e. resources are assigned to the user equipment on a semi-persistent basis (semi-persistent resource assignment). The benefit is the saving of PDCCH resources for initial HARQ transmissions. Semi-persistent scheduling can be used in PCell in Rel-10, but not in SCell.

[0071] One example of a service that can be scheduled using semi-persistent scheduling is voice over IP (VoIP). During a talk-spurt, VoIP packets are generated every 20 ms at the codec unit. Therefore, the eNodeB can persistently assign uplink or the corresponding downlink resources every 20 ms, which can then be used for the transmission of voice over IP packets. Generally, semi-persistent scheduling is advantageous for services with a predictable traffic behavior, i.e. constant bit rate, periodic packet arrival times.

[0072] The user equipment also monitors the PDCCH in the subframes where it has been persistently assigned resources for initial transmission. A dynamic (scheduled) grant (i.e. a PDCCH with CRC masked with C-RNTI) can override the semi-persistent resource assignment. In case the user equipment finds its C-RNTI on the L1 / L2 control channel in a subframe where the user equipment has an assigned semi-persistent resource, this L1 / L2 control channel assignment overrides the persistent resource assignment for that transmission time interval and the user equipment does not follow the dynamic grant. When the user equipment does not find a dynamic grant, it transmits / receives according to the semi-persistent resource assignment.

[0073] The configuration of semi-persistent scheduling is done by RRC signaling. Within the radio resource control (RRC) signaling, for example, the periodicity of the persistent assignment is signaled, e.g. PS_PERIOD. The activation and exact timing of the persistent assignment, as well as the physical resources and transport format parameters are sent via PDCCH signaling. Once semi-persistent scheduling is activated, the user equipment follows the semi-persistent resource assignment according to the SPS activation PDCCH every PS_PERIOD. In essence, the user equipment stores the SPS activation PDCCH content and follows the PDCCH with the signaled periodicity.

[0074] In order to distinguish between a dynamic PDCCH and a PDCCH activating semi-persistent scheduling (also referred to as SPS activation PDCCH), a separate identity is introduced. Basically, the CRC of the SPS activation PDCCH is masked with this additional identity, referred to as SPS C-RNTI. The size of the SPS C-RNTI is also 16 bits, same as the regular C-RNTI. Furthermore, the SPS C-RNTI is also user equipment specific, i.e. each user equipment configured for semi-persistent scheduling is assigned a unique SPS C-RNTI.

[0075] In case the user equipment detects that a semi-persistent resource assignment is activated by a corresponding SPS activation PDCCH, the user equipment will store the PDCCH content (i.e. the semi-persistent resource allocation) and apply it every semi-persistent scheduling interval, i.e. via the periodicity signaled via RRC. As already mentioned, the dynamic assignment (i.e. signaled on a dynamic PDCCH) is only a "one-shot assignment". The retransmission of the SPS assignment is also signaled using the SPS C-RNTI. In order to distinguish between an SPS activation and an SPS retransmission, the NDI (New Data Indicator) bit is used. An SPS activation is indicated by setting the NDI bit to 0. An SPS PDCCH with the NDI bit set to 1 indicates a retransmission for the initial transmission of the semi-persistent scheduling.

[0076] Similar to the activation of semi-persistent scheduling, the eNodeB can also disable semi-persistent scheduling, also referred to as SPS resource release. There are several options on how semi-persistent scheduling de-allocation can be signaled. One option would be to use PDCCH signaling, where some PDCCH fields are set to certain pre-defined values, i.e., SPS PDCCH indicating zero size resource allocation. Another option would be to use MAC control signaling.

[0077] In the following, further information is provided on how the eNB learns whether the UE is sending periodic data and when a SPS configuration can be setup.

[0078] When a new bearer is established, according to the dedicated bearer activation procedure in TS 23.401, the MME signals a bearer setup request (EPS Bearer Identity, EPS Bearer QoS, Session Management Request, S1-TEID) message to the eNodeB. The eNodeB maps the EPS Bearer QoS to radio bearer QoS. Then, the eNodeB signals an RRC Connection Reconfiguration (Radio Bearer QoS, Session Management Request, EPS RB Identity) message to the UE.

[0079] The EPS Bearer QoS profile includes the parameters QCI, ARP, GBR and MBR. Each EPS bearer (GBR and non-GBR) is associated with the following bearer level QoS parameters:

[0080] - QoS class identifier (QCI);

[0081] - Allocation and retention priority (ARP).

[0082] The QCI is a scalar used as a reference to access node specific parameters (e.g., scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.) controlling the packet forwarding treatment at the bearer level and has been pre-configured by the operator owning the access node (e.g., eNodeB). The one-to-one mapping of standardized QCI values to standardized characteristics is captured in TS 23.203, as shown in the table below based on one of TS 23.203.

[0083]

[0084]

[0085] As it is clear from the table, the QCI value 1 corresponds to "Conversational Voice", i.e., Voice over IP (VoIP). When the eNB receives a "bearer setup request" message with QCI value 1, the eNB knows that this bearer is established for VoIP and can apply a SPS configuration to allocate periodic resources to the UE to send VoIP data.

[0086] LTE device-to-device (D2D) proximity services (ProSe)

[0087] Proximity-based applications and services represent an emerging social technology trend. Identified areas include services related to commercial services and public safety that operators and users will be interested in. The introduction of proximity services (ProSe) capabilities in LTE will enable the 3GPP industry to serve this developing market and at the same time will serve the urgent needs of several public safety groups that are committed to LTE.

[0088] Device-to-device (D2D) communication is a component of the technology introduced in LTE-Release 12, which enables D2D as an underlay to cellular networks to increase spectral efficiency. For example, if the cellular network is LTE, all data carrying physical channels use SC-FDMA for D2D signaling. In D2D communication, user equipment transmit data signals to each other over a direct link using cellular resources, rather than through a radio base station. Throughout the invention, the terms "D2D", "ProSe" and "sidelink" are interchangeable.

[0089] D2D communication in LTE focuses on two areas: discovery and communication.

[0090] ProSe (Proximity-based Services) direct discovery is defined as a procedure used by a ProSe-enabled UE to discover other ProSe-enabled UEs within its proximity using E-UTRA direct radio signals via the PC5 interface.

[0091] In D2D communication, UEs transmit data signals to each other over a direct link using cellular resources, rather than through a base station (BS). D2D users communicate directly while remaining under the control of a BS (i.e., at least when in the coverage of an eNB). Thus, D2D can improve system performance by reusing cellular resources.

[0092] D2D is assumed to operate in the uplink LTE spectrum (in the case of FDD) or the uplink subframes of a cell of a given coverage (in the case of TDD, except when outside the coverage). Furthermore, D2D transmission / reception does not use full duplex on a given carrier. From the perspective of a single UE, D2D signal reception and LTE uplink transmission do not use full duplex on a given carrier, i.e., D2D signal reception and LTE UL transmission cannot be done simultaneously.

[0093] In D2D communication, when one specific UE1 has the role of the transmitter (transmitting user equipment or transmitting terminal), UE1 transmits data and another UE2 (receiving user equipment) receives it. UE1 and UE2 can change their transmitting and receiving roles. The transmission from UE1 can be received by one or more UEs like UE2.

[0094] ProSe Direct Communication Layer 2 link

[0095] In short, ProSe Direct One-to-One communication is realized by establishing a secure Layer 2 link over PC5 between two UEs. Each UE has a Layer 2 ID for unicast communication, which is included in the source Layer 2 ID field of every frame it transmits on the Layer 2 link and in the destination Layer 2 ID of every frame it receives on the Layer 2 link. The UE needs to ensure that the Layer 2 ID for unicast communication is at least locally unique. Therefore, the UE should be prepared to handle Layer 2 ID conflicts with neighboring UEs using an unspecifed mechanism (e.g. assigning a new Layer 2 ID for unicast communication by itself when a conflict is detected). The Layer 2 link for ProSe Direct One-to-One communication is identified by the combination of the Layer 2 IDs of both UEs. This means that a UE can participate in multiple Layer 2 links for ProSe Direct One-to-One communication using the same Layer 2 ID.

[0096] One-to-One ProSe Direct Communication includes procedures like detailed in TR 23.713 current version v13.0.0 section 7.1.2, which is incorporated herein by reference:

[0097] • Establishing a secure Layer 2 link over PC5.

[0098] • IP address / prefix allocation.

[0099] • Layer 2 link maintenance over PC5.

[0100] • Layer 2 link release over PC5.

[0101] Figure 3 Figure illustrates how to establish a secure Layer 2 link over PC5 interface.

[0102] 1. UE-1 sends a Direct Communication Request message to UE-2 in order to trigger mutual authentication. The link initiator (UE-1) needs to know the Layer 2 ID of the peer (UE-2) in order to perform step 1. As an example, the link initiator can learn the Layer 2 ID of the peer by first performing a discovery procedure or by already participating in a ProSe One-to-Many communication including the peer.

[0103] 2. UE-2 initiates the procedure for mutual authentication. Successful completion of the authentication procedure enables the establishment of a secure Layer-2 link over PC5.

[0104] A UE participating in isolated (non-relay) one-to-one communication can also use a link-local address. The PC5 signaling protocol shall support keep-alive functionality, which is used to detect when a UE is not in the ProSe communication range, so that the UE can continue with implicit Layer-2 link release. Layer-2 link release over PC5 can be performed by using a disconnect request message sent to the other UE, which also deletes all associated context data. Upon receiving the disconnect request message, the other UE responds with a disconnect response message and deletes all context data associated with the Layer-2 link.

[0105] ProSe Direct Communication Related Identifiers

[0106] The current version 13.2.0 of 3GPP TS 36.300 defines in subclause 8.3 the following identifiers for ProSe Direct Communication:

[0107] • ProSe Application ID: a unique identifier for ProSe Direct Communication scheduling; SL-RNTI • Source Layer-2 ID: identifies the sender of data in sidelink ProSe Direct Communication. The Source Layer-2 ID is 24 bits long and is used together with the ProSe Layer-2 Destination ID and LCID to identify the RLC UM entity and PDCP entity in the receiver;

[0108] Source layer-2 ID • Destination Layer-2 ID: identifies the target of data in sidelink ProSe Direct Communication. The Destination Layer-2 ID is 24 bits long and is split into two bit strings in the MAC layer:

[0109] • one bit string is the LSB part (8 bits) of the Destination Layer-2 ID and is forwarded to the physical layer as the Sidelink Control Layer-1 ID. This identifies the target of intended data in the Sidelink Control and is used to filter packets at the physical layer. Destination layer-2 ID • the second bit string is the MSB part (16 bits) of the Destination Layer-2 ID and is carried within the MAC header. This is used to filter packets at the MAC layer.

[0110]

[0111]

[0112] ​​​Group formation and configuration of source Layer-2 ID, destination Layer-2 ID and sidelink control L1 ID in the UE does not require access stratum signaling. These identities are provided by higher layers or derived from identities provided by higher layers. In case of groupcast and broadcast, the ProSe UE ID provided by higher layers is directly used as source Layer-2 ID and the ProSe Layer-2 group ID provided by higher layers is directly used as destination Layer-2 ID in the MAC layer. In case of one-to-one communication, the source Layer-2 ID and the destination Layer-2 ID are provided by higher layers.

[0113] Radio resource allocation for proximity services

[0114] From the perspective of the transmitting UE, a Proximity Services enabled UE (ProSe-enabled UE) can operate in two modes for resource allocation:

[0115] Mode 1 refers to eNB-scheduled resource allocation, where the UE requests transmission resources from the eNB (or Release 10 relay node) and the eNodeB (or Release 10 relay node) in turn schedules the resources to be used by the UE for transmitting direct data and direct control information (e.g. scheduling assignment). The UE needs to be RRC_CONNECTED in order to transmit data. Specifically, the UE transmits a scheduling request (D-SR or Random Access) to the eNB in the usual way, followed by a buffer status report (BSR) (see also section "Transmission procedure for D2D communication" below). Based on the BSR, the eNB can determine that the UE has data for ProSe direct communication transmission and can estimate the resources needed for transmission.

[0116] On the other hand, Mode 2 refers to UE-autonomous resource selection, where the UE itself selects resources (time and frequency) from a resource pool to transmit direct data and direct control information (i.e. SA). One resource pool is defined, for example, by the content of SIB 18 (i.e. by the field commTxPoolNormalCommon), this specific resource pool is broadcasted in the cell and then commonly available to all UEs in the cell that are still in RRC_Idle state. Effectively, the eNB can define up to four different instances of said pool, one for each of the four resource pools for transmitting SA messages and direct data. However, in Release 12, the UE shall always use the first resource pool defined in the list, even if it is configured with multiple resource pools. This restriction is removed for Release 13, i.e. the UE can transmit on multiple configured resource pools within one SC period. How the UE selects the resource pool for transmission is further outlined below (further specified in TS 36.321).

[0117] As an alternative, another resource pool can be defined by the eNB and signaled in SIB 18 (i.e. by using the field commTxPoolExceptional) which can be used by the UE in exceptional cases.

[0118] What resource allocation mode the UE is going to use can be configured by the eNB. Furthermore, what resource allocation mode the UE is going to use for D2D data communication can also depend on the RRC state (i.e. RRC_IDLE or RRC_CONNECTED) and the coverage status of the UE (i.e. in-coverage, out-of-coverage). If the UE has a serving cell (i.e. the UE is RRC_CONNECTED or camping on a cell in RRC_IDLE), the UE is considered in-coverage.

[0119] The following rules regarding the resource allocation mode apply to the UE:

[0120] • If the UE is out-of-coverage, the UE can only use mode 2;

[0121] • If the UE is in-coverage, the UE can use mode 1 if the eNB configures the UE accordingly;

[0122] • If the UE is in-coverage, the UE can use mode 2 if the eNB configures the UE accordingly;

[0123] • The UE can only change from mode 1 to mode 2 (and vice versa) if it is configured by the eNB to do so, when no exceptional condition exists. If the UE is in-coverage, the UE shall only use the mode indicated by the eNB configuration, unless one of the exceptional conditions occurs;

[0124] o The UE considers itself under an exceptional condition, e.g. when T311 or T301 is running;

[0125] • When an exceptional condition occurs, the UE is allowed to temporarily use mode 2 even if it is configured to use mode 1.

[0126] When in the coverage area of an E-UTRA cell, the UE shall only perform ProSe direct communication transmission on the UL carrier on the resources allocated by that cell, even if the resources of that carrier have been pre-configured in the UICC (Universal Integrated Circuit Card), for example.

[0127] For a UE in RRC_IDLE, the eNB can choose one of the following options:

[0128] • The eNB can provide in SIB the mode 2 transmission resource pool. UEs authorized for ProSe direct communication use these resources for ProSe direct communication in RRC_IDLE;

[0129] • The eNB can indicate in SIB that it supports D2D but does not provide resources for ProSe Direct Communication. The UE needs to enter RRC CONNECTED to perform ProSe Direct Communication transmission.

[0130] For a UE in RRC CONNECTED:

[0131] • A UE in RRC CONNECTED authorized to perform ProSe Direct Communication transmission indicates to the eNB that it wants to perform ProSe Direct Communication transmission when it needs to perform ProSe Direct Communication transmission;

[0132] • The eNB uses the UE context received from the MME to verify whether the UE in RRC CONNECTED is authorized for ProSe Direct Communication transmission;

[0133] • The eNB can configure a UE in RRC CONNECTED with a mode 2 resource allocation transmission resource pool via dedicated signaling, which can be used without restriction while the UE is in RRC CONNECTED. Alternatively, the eNB can configure a UE in RRC CONNECTED with a mode 2 resource allocation transmission resource pool via dedicated signaling, the UE is only allowed to use this mode 2 resource allocation transmission resource pool in exceptional cases, otherwise relying on mode 1.

[0134] The resource pool for scheduling allocation when the UE is out of coverage can be configured as follows:

[0135] • A resource pool for reception is pre-configured.

[0136] • A resource pool for transmission is pre-configured.

[0137] The resource pool for scheduling allocation when the UE is in coverage can be configured as follows:

[0138] • A resource pool for reception is configured by the eNB via RRC, in dedicated or broadcast signaling.

[0139] • If mode 2 resource allocation is used, a resource pool for transmission is configured by the eNB via RRC.

[0140] • If mode 1 resource allocation is used, the SCI (Sidelink Control Information) resource pool (also called Scheduling Allocation, SA, resource pool) for transmission is unknown to the UE.

[0141] • If mode 1 resource allocation is used, the eNB schedules specific resources for the sidelink control information (scheduling assignment) transmission. The specific resources allocated by the eNB are within the resource pool used for receiving the SCI provided to the UE.

[0142] Figure 4 The use of transmission / reception resources for overlay (LTE) and underlying (D2D) systems is illustrated.

[0143] Basically, the eNodeB controls whether the UE can apply mode 1 or mode 2 transmission. Once the UE knows its resources on which it can transmit (or receive) D2D communication, the UE only uses the corresponding resources for the corresponding transmission / reception. For example, in Figure 4 the D2D subframes will be used for receiving or transmitting D2D signals only. Since the UE operating as a D2D device operates in a half duplex mode, the UE can receive or transmit D2D signals at any point in time. Similarly, Figure 4 the other subframes shown in

[0144] Transmission procedure for D2D communication

[0145] The D2D data transmission procedure differs depending on the resource allocation mode. As described above for mode 1, the eNB explicitly schedules the resources for scheduling assignment and D2D data communication after a corresponding request from the UE. In particular, the eNB can inform the UE that D2D communication is generally allowed, but no mode 2 resources (i.e. resource pool) are provided; this can be done, for example, by the exchange of a D2D communication interest indication by the UE and a corresponding response (D2D communication response), wherein the corresponding exemplary ProSeCommConfig information element will not include commTxPoolNormalCommon, meaning that a UE wanting to start a direct communication involving transmission has to request the E-UTRAN to allocate resources for each individual transmission. Thus, in this case, the UE has to request resources for each individual transmission, and the following, for this mode 1 resource allocation, exemplary different steps of the request / grant procedure are listed:

[0146] • Step 1 : The UE transmits an SR (scheduling request) to the eNB via PUCCH;

[0147] • Step 2: The eNB grants UL resources (for the UE to transmit a BSR) via PDCCH scrambled by C-RNTI;

[0148] • Step 3: The UE transmits a D2D BSR indicating the buffer status via PUSCH;

[0149] • Step 4: The eNB grants D2D resources (for the UE to transmit data) via PDCCH scrambled by D2D-RNTI;

[0150] • Step 5: The D2D Tx UE transmits SA / D2D data according to the grant received in Step 4.

[0151] The Scheduling Assignment (SA), also called SCI (Sidelink Control Information), is a compact (low payload) message containing control information such as: pointer to time-frequency resources for the corresponding D2D data transmission, modulation and coding scheme, and group destination ID. The SCI transmission conveys the sidelink scheduling information for one (ProSE) destination ID. The content of the SA (SCI) is basically according to the grant received in Step 4 above. The D2D grant and SA content (i.e. SCI content) is defined in subclause 5.4.3 of the current version 13.0.0 of the 3GPP technical standard 36.212, incorporated herein by reference, which defines in particular the SCI format 0 (see above for the content of the SCI format 0).

[0152] On the other hand, for mode 2 resource allocation, the above steps 1-4 are basically not necessary, and the UE autonomously selects the resources for SA and D2D data transmission from a pool of transmission resources configured and provided by the eNB.

[0153] Figure 5 An exemplary illustration of the transmission of the Scheduling Assignment and D2D data for two UEs (UE-1 and UE-2) is shown, where the resources for the transmission of the Scheduling Assignment are periodic, and the resources for the D2D data transmission are indicated by the corresponding Scheduling Assignment.

[0154] Figure 6 The D2D communication timing for mode 2 (autonomous scheduling) during one SA / data period (also called SC period, Sidelink Control period) is illustrated. Figure 7 The D2D communication timing for mode 1 (eNB scheduled allocation) during one SA / data period is illustrated. The SC period is the time period including the transmission of the Scheduling Assignment and its corresponding data. As from the illustration, the D2D data transmission is preceded by the transmission of the Scheduling Assignment. Figure 6As can be seen from Figure 6 , for the eNB scheduled resource allocation mode (Mode 1), the D2D data transmission, i.e. more specifically the T-RPT pattern / bitmap, starts in the next UL subframe after the last SA transmission repetition in the SA resource pool. As already explained for Figure 7 , the assumption is made that three retransmissions are performed (i.e. second, third and fourth transmission of the same MAC PDU). The Mode2 T-RPT bitmap (transmitted time resource pattern, T-RPT) basically defines the timing of the MAC PDU transmission (first transmission) and its retransmissions (second, third and fourth transmission). The SA pattern basically defines the timing of the initial transmission of the SA and its retransmissions (second, third and fourth transmission).

[0155] As currently specified in the standard, for one sidelink grant, e.g. transmitted by the eNB or selected by the UE itself, the UE can transmit multiple transport blocks MAC PDUs (only one per subframe (TTI), i.e. one after the other), but only to one ProSe Destination Group. Furthermore, the retransmissions of one transport block have to end before the start of the first transmission of the next transport block, i.e. only one HARQ process is used per sidelink grant for transmitting multiple transport blocks. Furthermore, the UE can have and use multiple sidelink grants per SC period, but selects a different ProSe Destination for each of them. Thus, in one SC period, the UE can transmit data to only one ProSe Destination at a time.

[0156] As can be seen from Figure 7 , for the eNB scheduled resource allocation mode (Mode 1), the D2D data transmission, i.e. more specifically the T-RPT pattern / bitmap, starts in the next UL subframe after the last SA transmission repetition in the SA resource pool. As already explained for Figure 6 , the assumption is made that three retransmissions are performed (i.e. second, third and fourth transmission of the same MAC PDU). The Mode2 T-RPT bitmap (transmitted time resource pattern, T-RPT) basically defines the timing of the MAC PDU transmission (first transmission) and its retransmissions (second, third and fourth transmission). The SA pattern basically defines the timing of the initial transmission of the SA and its retransmissions (second, third and fourth transmission).

[0157] The sidelink data transmission procedure can be found in section 5.14 of the 3GPP standard document TS 36.321 v13.0.0, which is incorporated herein by reference. Therein, mode 2 autonomous resource selection is described in detail, distinguishing between being configured with a single radio resource pool or multiple radio resource pools. Assuming mode 2 autonomous resource selection, the following steps are taken from said section of TS 36.321 :

[0158] In order to transmit on the SL-SCH (Sidelink Shared Channel), the MAC entity must have at least one sidelink grant. The sidelink grant is selected as follows:

[0159] If the MAC entity is configured by upper layers to transmit using one or multiple resource pools and there is more data available in the STCH (Sidelink Traffic Channel) than can be transmitted in the current SC period, the MAC entity shall, for each sidelink grant to be selected:

[0160] • if configured by upper layers to use a single resource pool:

[0161] - then select this resource pool for use;

[0162] • else, if configured by upper layers to use multiple resource pools:

[0163] - then select from the resource pools configured by upper layers the resource pool(s) whose associated priority list includes the priority of the sidelink logical channel with the highest priority in the MAC PDU to be transmitted for use;

[0164] NOTE: If more than one resource pool has an associated priority list that includes the priority of the sidelink logical channel with the highest priority in the MAC PDU to be transmitted, which one of those resource pools to select is left to UE implementation.

[0165] • randomly select time and frequency resources for the SL-SCH and SCI of the sidelink grant from the selected resource pool(s). The random function shall be such that each of the allowed selections can be chosen with equal probability;

[0166] • use the selected sidelink grant to determine the set of subframes in which the transmission of the SCI and the first transport block occur according to subclause 14.2.1 of TS 36.213, which is incorporated herein by reference (this step refers to selection of T-RPT and SA mode as explained in connection with Figure 7 );

[0167] • consider the selected sidelink grant to be the configured sidelink grant that occurs in those subframes that start at the beginning of the first available SC period that starts at least 4 subframes after the subframe in which the sidelink grant was selected;

[0168] • clear the configured sidelink grant at the end of the corresponding SC period;

[0169] Note: The retransmission on SL-SCH does not occur after the configured sidelink grant has been cleared.

[0170] Note: If the MAC entity is configured by upper layers to transmit using one or more resource pools, how many sidelink grants are selected within one SC period taking into account the number of sidelink processes is left to UE implementation.

[0171] The MAC entity shall, for each subframe:

[0172] - if the MAC entity has a configured sidelink grant occurring in this subframe:

[0173] - then if the configured sidelink grant corresponds to the transmission of an SCI:

[0174] - then instruct the physical layer to transmit the SCI corresponding to the configured sidelink grant.

[0175] - else if the configured sidelink grant corresponds to the transmission of a first transport block:

[0176] - then deliver the configured sidelink grant and the associated HARQ information to the sidelink HARQ entity for this subframe.

[0177] Note: If the MAC entity has multiple configured grants occurring in one subframe and if it is not possible to process all of them due to single cluster SC-FDM limitation, which of these is processed according to the above procedure is left to UE implementation.

[0178] The above text taken from the 3GPP technical standard can be further clarified. For example, the step of randomly selecting time and frequency resources is random with respect to which specific time / frequency resources are selected, but for example not random with respect to the amount of time / frequency resources selected in total. The amount of resources selected from the resource pool depends on the amount of data to be transmitted with said sidelink grant to be selected autonomously. In turn, the amount of data to be transmitted depends on the preceding step of selecting a ProSe destination group and the amount of corresponding data ready for transmission to said ProSe destination group. As described later in the sidelink LCP procedure, the ProSe destination is first selected.

[0179] Furthermore, the sidelink processing associated with the sidelink HARQ entity is responsible for instructing the physical layer to generate and perform the transmission accordingly, as apparent from section 5.14.1.2.2 of 3GPP TS 36.321 v13.0.0, which is incorporated herein by reference. In short, after determining the sidelink grant and the sidelink data to be transmitted, the physical layer takes care of actually transmitting the sidelink data based on the sidelink grant and the necessary transmission parameters.

[0180] The above discusses the current status of the 3GPP standard for D2D communication. However, it should be noted that there are always discussions on how to further improve and enhance D2D communication, which will likely result in some changes to D2D communication in future releases. The present invention, which will be described later, should also apply to those later releases.

[0181] ProSe network architecture and ProSe entities

[0182] Figure 8 A high level exemplary architecture for the non-roaming case is illustrated, including different ProSe applications in the respective UEs A and B, and a ProSe application server and a ProSe function in the network. Figure 8 The exemplary architecture is taken from TS 23.303 v.13.2.0, chapter 4.2 "Architectural Reference Model", which is incorporated herein by reference.

[0183] The functional entities are presented and explained in detail in TS 23.303 subclause 4.4 "Functional Entities", which is incorporated herein by reference. The ProSe function is a logical function that serves network related actions required for ProSe and plays different roles for each feature of ProSe. The ProSe function is part of the EPC of 3GPP and provides all relevant network services related to proximity services, such as authorization, authentication, data handling, etc. For ProSe direct discovery and communication, a UE can obtain a specific ProSe UE identity, other configuration information, and authorization from the ProSe function over the PC3 reference point. Multiple ProSe functions can be deployed in the network, but for ease of illustration, a single ProSe function is presented. The ProSe function comprises three main sub-functions that perform different roles depending on the ProSe feature: a direct provision function (DPF), a direct discovery name management function, and an EPC level discovery function. The DPF is used to provide the UE with the necessary parameters to use ProSe direct discovery and ProSe direct communication.

[0184] The term "UE" used in said connection refers to a ProSe-enabled UE that supports ProSe functionality, such as:

[0185] • Exchange of ProSe control information between a ProSe-enabled UE and the ProSe Function over the PC3 reference point.

[0186] • Procedures for open ProSe direct discovery of other ProSe-enabled UEs over the PC5 reference point.

[0187] • Procedures for one-to-many ProSe direct communication over the PC5 reference point.

[0188] • Procedures as a ProSe UE-to-Network relay. Remote UEs communicate with the ProSe UE-to-Network relay over the PC5 reference point. The ProSe UE-to-Network relay uses layer 3 packet forwarding.

[0189] • Exchange of control information between ProSe UEs over the PC5 reference point, e.g., for UE-to-Network relay detection and ProSe direct discovery.

[0190] • Exchange of ProSe control information between another ProSe-enabled UE and the ProSe Function over the PC3 reference point. In case of a ProSe UE-to-Network relay, the remote UE will send this control information over the PC5 user plane to be relayed to the ProSe Function over the LTE-Uu interface.

[0191] • Configuration of parameters (e.g., including IP address, ProSe Layer 2 group ID, group security material, radio resource parameters). These parameters can be pre-configured in the UE or, if in coverage, provided to the ProSe Function in the network through signaling over the PC3 reference point.

[0192] The ProSe Application Server supports storage of EPC ProSe User IDs, ProSe Function IDs, and mapping of application layer user IDs and EPC ProSe User IDs. The ProSe Application Server (AS) is an entity outside the 3GPP scope. The ProSe application in the UE communicates with the ProSe AS via the application layer reference point PC1. The ProSe AS is connected to the 3GPP network via the PC2 reference point.

[0193] Vehicle communications - V2X services

[0194] A new study item has been set up in 3GPP to consider the usefulness of new LTE features for the automotive industry - including Proximity Services (ProSe) and LTE-based broadcast services. Thus, ProSe functionality is considered to provide a good basis for V2X services. Connected car technology aims to address some of the biggest challenges in the ground transportation industry, such as safety, mobility, and traffic efficiency.

[0195] V2X communication is the communication of information from a vehicle to any entity that can impact the vehicle and vice versa. This exchange of information can be used to improve safety, mobility, and environmental applications to include driver-assisted vehicle safety, speed adaptation and warnings, emergency response, travel information, navigation, traffic operations, commercial fleet planning, and payment transactions.

[0196] LTE support for V2X services includes three types of different use cases as follows:

[0197] • V2V: covers LTE-based communication between vehicles.

[0198] • V2P: covers LTE-based communication between vehicles and devices carried by individuals (e.g., handheld terminals carried by pedestrians, cyclists, drivers, or passengers).

[0199] • V2I: covers LTE-based communication between vehicles and roadside units.

[0200] These three types of V2X can use "cooperative awareness" to provide more intelligent services to end users. This means that transportation entities such as vehicles, roadside infrastructure, and pedestrians can collect knowledge of their local environment (e.g., information received from other vehicles or nearby sensor devices) to process and share that knowledge in order to provide more intelligent services, such as cooperative collision warnings or automated driving.

[0201] With respect to V2V communication, E-UTRAN allows UEs in close proximity to each other to exchange V2V related information using E-UTRA(N) when the permission, authorization, and proximity criteria are met. The proximity criteria can be configured by the MNO (Mobile Network Operator). However, a UE supporting V2V services can exchange such information when served by an E-UTRAN supporting V2X services or not.

[0202] A UE supporting V2V applications sends application layer information (e.g., about its position, dynamics, and properties as part of a V2V service). The V2V payload must be flexible in order to accommodate different information content, and information can be sent periodically according to a configuration provided by the MNO.

[0203] V2V is mainly based on broadcast; V2V includes: exchanging V2V related application information directly between different UEs; and / or exchanging V2V related application information between different UEs via infrastructure (e.g. RSU, application server, etc.) supporting V2X services due to limited direct communication range of V2V.

[0204] Regarding V2I communication, a UE supporting V2I application sends application layer information to a roadside unit, which in turn can send the application layer information to a group of UEs or a UE supporting V2I application.

[0205] V2N (Vehicle-to-Network, eNB / CN) is also introduced, where one party is a UE and the other party is a service entity, both supporting V2N application and communicating with each other via LTE network.

[0206] Regarding V2P communication, E-UTRAN allows these UEs in close proximity to each other to exchange V2P related information using E-UTRAN when the allow, authorization and close proximity criteria are met. The close proximity criteria can be configured by the MNO. However, a UE supporting V2P service can exchange such information even in case of E-UTRAN service not supporting V2X service.

[0207] A UE supporting V2P application sends application layer information. Such information can be broadcasted by a vehicle with a UE supporting V2X service (e.g. warning to pedestrians), and / or by a pedestrian with a UE supporting V2X service (e.g. warning to vehicles).

[0208] V2P includes: exchanging V2P related application information directly between different UEs (one for vehicles and the other for pedestrians); and / or exchanging V2P related application information between different UEs via infrastructure (e.g. RSU, application server, etc.) supporting V2X services due to limited direct communication range of V2P.

[0209] For this new study item V2X, 3GPP has provided specific terminology and definitions in the current version 13.0.0 of TR 21.905, which can be reused for this application.

[0210] Roadside Unit (RSU): an entity supporting V2I services that can use V2I applications to send to and receive from UEs. RSU can be implemented in eNB or fixed UE.

[0211] V2I service: a type of V2X service where one party is a UE and the other party is a RSU, both using V2I application.

[0212] V2N service: A type of V2X service where one party is a UE and the other party is a service entity, both using a V2N application and communicating with each other via LTE network entities.

[0213] V2P service: A type of V2X service where both parties of the communication are UEs using a V2P application.

[0214] V2V service: A type of V2X service where both parties of the communication are UEs using a V2V application.

[0215] V2X service: A type of communication service involving a transmitting or receiving UE using a V2V application via 3GPP transmission. It can be further divided into V2V service, V2I service, V2P service and V2N service based on the other party involved in the communication.

[0216] Different types of messages are defined for and will be defined for V2V communication. ETSI has defined two different types of messages for Intelligent Transport Systems (ITS), see corresponding European standards ETSI EN 302 637-2 vl.3.1 and ETSI EN 302 637-3 vl.2.1:

[0217] • Cooperative Awareness Message (CAM), which is broadcasted continuously by a vehicle to reflect its status.

[0218] • Decentralized Environmental Notification Message (DENM), which is triggered only when a vehicle related safety event occurs.

[0219] As V2V and ITS standardization is in its infancy, it is expected that other messages can be defined in the future.

[0220] The CAM is broadcasted continuously by an ITS-Station (ITS-S) to exchange status information with other ITS-S, thus the impact on traffic load is greater than the event triggered DENM message. For this reason, the traffic characteristics of the CAM message defined by ETSI for ITS are considered to be more representative of V2V traffic.

[0221] Cooperative Awareness Message (CAM) is a message exchanged in ITS networks between ITS-Ss to create and maintain awareness of each other and to support cooperative performance of vehicles using the road network. Point-to-multipoint communication shall be used to send CAMs such that a CAM is sent from an originating ITS-S to receiving ITS-Ss located in the direct communication range of the originating ITS-S. CAM generation shall be triggered and managed by the Cooperative Awareness Basic Service, which defines the time interval between two consecutive CAM generations. Currently, the upper and lower bounds of the transmission interval are 100 ms (i.e., a CAM generation rate of 10 Hz) and 1000 ms (i.e., a CAM generation rate of 1 Hz). The underlying philosophy of ETSI ITS is to send a CAM when there is new information (e.g., new position, new acceleration, or new heading value) to share. Correspondingly, when a vehicle is moving slowly and on a constant heading and speed, a high CAM generation rate does not bring real benefits to CAMs, showing only minimal differences. The transmission frequency of a CAM of one vehicle varies between 1 Hz and 10 Hz as a function of the vehicle dynamics (e.g., speed, acceleration, and heading). For example, the slower a vehicle travels, the fewer CAMs are triggered and sent. Vehicle speed is the main influencing factor of CAM traffic generation.

[0222] The CAM generation trigger conditions are currently defined in ETSI EN 302 637-2 vl.3.1 clause 6.1.3 and are as follows:

[0223] 1) The time elapsed since the last CAM generation is equal to or greater than T_GenCam_Dcc (a parameter providing the minimum time interval between two consecutive CAM generations) in order to reduce CAM generation according to the channel usage requirements of the decentralized congestion control (DCC) and given one of the following ITS-S dynamic related conditions:

[0224] • The absolute difference between the current heading of the originating ITS-S and the heading included in the CAM previously sent by the originating ITS-S exceeds 4°;

[0225] • The distance between the current position of the originating ITS-S and the position included in the CAM previously sent by the originating ITS-S exceeds 4 m;

[0226] • The absolute difference between the current speed of the originating ITS-S and the speed included in the CAM previously sent by the originating ITS-S exceeds 0.5 m / s.

[0227] 2) The time elapsed since the last CAM generation is equal to or greater than T_GenCam and equal to or greater than T_GenCam_Dcc. The parameter T_GenCam represents the currently valid upper bound of the CAM generation interval.

[0228] If one of the two above conditions is fulfilled, a CAM shall be generated immediately.

[0229] The CAM contains status and attribute information of the originating ITS-S. The content of the CAM varies depending on the type of ITS-S, as will be explained in more detail below. For a vehicle ITS-S, the status information can include time, location, motion status, activated systems, etc., and the attribute information can include data on size, vehicle type, and role in road traffic, etc. Upon reception of a CAM, the receiving ITS-S becomes aware of the existence, type, and status of the originating ITS-S. The received information can be used by the receiving ITS-S to support several ITS applications. For example, by comparing the status of the originating ITS-S with its own status, the receiving ITS-S is able to estimate the collision risk with the originating ITS-S and, if needed, can inform the driver of the vehicle via a HMI (Human Machine Interface). As described in detail in clause 7 of ETSI EN 302 637-2 v 1.3.1, which is incorporated herein by reference, the CAM comprises one common ITS PDU header and multiple containers, which together constitute the CAM. The ITS PDU header is a common header, which includes information on the protocol version, the message type, and the ITS-S ID of the originating ITS-S. For a vehicle ITS-S, the CAM shall include one basic container and one high frequency container, and can also include one low frequency container and one or more other special containers. The basic container includes basic information related to the originating ITS-S. The high frequency container contains highly dynamic information of the originating ITS-S. The low frequency container contains static and non-highly dynamic information of the originating ITS-S. The special vehicle container contains information specific to the vehicle role of the originating vehicle ITS-S. The general structure of the CAM is shown in Figure 9

[0230] The following table gives an overview of the different components of the V2V message data and the packet size:

[0231]

[0232]

[0233] A vehicle ITS-S generates a CAM, which shall include at least the high frequency vehicle container, and optionally the low frequency vehicle container. A vehicle ITS-S having a specific role in road traffic, such as public transport, shall provide status information in the special vehicle container.

[0234] ​Each V2V message exchanged between vehicles has to fulfill security requirements, including anonymity and integrity protection. Different security approaches can have different levels of security performance and overhead, which directly impact the packet size (due to security overhead) and message frequency (e.g., frequency of additional security credentials).

[0235] Both ETSI ITS and IEEE 1609.2 consider a Public Key Infrastructure (PKI) based security solution for V2X communication, which is an asymmetric based application layer security solution. Typically, each V2X message needs to carry a signature, as well as a certificate or digest of a certificate, to achieve anonymity and integrity protection. The typical size of signature, digest and certificate is 64 bytes, 8 bytes and 117 bytes, respectively.

[0236] As mentioned above, CAM messages can have different periodicity and / or different message size. Furthermore, the periodicity can even change over time depending on speed and other (smaller influencing) factors such as heading or angle. To provide an overview, the following table is provided, which identifies different possible message components (HF, LF, certificate) and resulting periodicity and message size depending on three different typical speed ranges.

[0237] CAM with PKI based security overhead (for vehicle speed > 144 km / h):

[0238]

[0239]

[0240] CAM with PKI based security overhead (speed ∈ [72, 144] km / h)

[0241]

[0242] CAM with PKI based security overhead (speed ∈ [48, 72] km / h)

[0243]

[0244] As is clear from the above table, the size of the components, and thus the size of the CAM, remains the same, but their generation / sending frequency changes with the different speed ranges. For the above table, it is assumed that the CAM HF component is sent together with the signature and digest, resulting in a message size of about 122 bytes (i.e. enough to transmit 8 bytes for the header, 18 bytes for the basic container, 23 bytes for the high frequency container, 64 bytes for the signature, and 8 bytes for the digest). The CAM LF component piggybacked on the high frequency component has a size of about 60 bytes additional, making the resulting CAM with all containers / components 182 bytes in size. The certificate component (also referred to as the security component) piggybacked on the high frequency component has a size of about 117 bytes additional, making the resulting CAM with all containers / components 299 bytes in size, or the resulting CAM without the CAM LF container / component is 239 bytes in size.

[0245] Figure 10 Fig. 1 illustrates the occurrence of three different components depending on the three different speed ranges introduced above, and how this results in different overall message sizes and overall periodicity. In Figure 10 the dashed boxes including the different components should indicate that the components are not sent separately, but as one CAM message.

[0246] Above, the periodic cooperative awareness messages have been described in great detail, also specifying their different content, specific periodicity, and message size. It should be noted, however, that although some of the above information has been standardized, other information such as the periodicity and message size has not been standardized and is based on assumptions. Furthermore, the standardization can change in the future, and thus also aspects of how the CAM is generated and sent. Furthermore, although currently the different components (CAM HF, CAM LF, certificate) are sent together when they fall together, i.e. as one message, this does not have to be the case. In the future, it is also possible that these containers / components are sent separately from each other, then possibly including a header each and also possibly being a basic container. Thus, the above detailed description of the CAM should be understood as an example conceived for illustration purposes, although the message size and periodicity are realistic and based on simulation results. Throughout this application, the above CAM message and its content, periodicity, and message size will be used in order to explain the underlying principles of the present application. What is important for the present application is that the V2V communication will require the vehicle UEs to send different data in a periodic manner, and it is foreseen that the periodicity can change quickly as a function of the vehicle dynamics, such as (relative) speed, angle, heading, and possibly other factors such as vehicle distance, etc. Thus, the challenge is that the vehicle UEs should be able to send several periodic packets with different and changing periodicity of different message sizes.

[0247] In order for the vehicle UEs to have radio resources on the sidelink for transmitting CAMs, mode 1 and / or mode 2 radio resource allocation is envisaged, as described above. For mode 1 radio resource allocation, the eNB allocates resources for SA messages and data for each SA period. However, when there is a large amount of traffic (e.g. high frequency periodic traffic), the overhead on the Uu link from the UE to the eNB can be significant.

[0248] As apparent from the above, many V2V traffics are periodic, such that 3GPP has agreed that for sidelink V2V communication mode 1 (i.e. eNB scheduled radio resource allocation), the eNB and the UE will support sidelink semi-persistent radio resource allocation.

[0249] However, the currently standardized semi-persistent allocation mechanism needs to be improved and adapted to the requirements and challenges of V2V traffics. SUMMARY

[0250] The non-limiting and exemplary embodiments provide an improved resource allocation method for vehicle communications of a vehicle mobile terminal.

[0251] The independent claims provide non-limiting and exemplary embodiments. Advantageous embodiments follow from the dependent claims.

[0252] Correspondingly, in one general first aspect, the technology herein disclosed features a vehicle mobile device comprising: a transmitter to transmit assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes to a radio base station; a receiver to receive from the radio base station a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations being configured to be usable for at least one of the D2D data transmissions, and to receive from the radio base station an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for each of the D2D data transmissions for the vehicle mobile device; and the transmitter to perform one or more D2D data transmissions based on the radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

[0253] Correspondingly, in a general first aspect, the technology disclosed herein is characterized by a radio base station comprising: a receiver that receives assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes from a vehicle mobile device; circuitry that configures a plurality of semi-persistent radio resource configurations based on a transmission period of the different possible transmission periods, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; a transmitter that transmits information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; the circuitry selects one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and the transmitter transmits an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

[0254] Correspondingly, in a general first aspect, the technology disclosed herein is characterized by a method for a vehicle mobile device, the method comprising: transmitting assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes to a radio base station; receiving, from the radio base station, a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations being configured to be usable for at least one of the D2D data transmissions, and receiving, from the radio base station, an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and performing one or more of the D2D data transmissions based on radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

[0255] Correspondingly, in a general first aspect, the technology disclosed herein is characterized by a method for a radio base station, the method comprising: receiving assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes from a vehicle mobile device; configuring a plurality of semi-persistent radio resource configurations based on a transmission period of the different possible transmission periods of one or more of the D2D data transmissions, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; transmitting information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and transmitting an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

[0256] Correspondingly, in one general aspect, features of the technology disclosed herein are directed to an integrated circuit for controlling a process of a vehicle mobile device, the process comprising: transmitting assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes to a radio base station; receiving, from the radio base station, a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations configured to be usable for at least one of the D2D data transmissions, and receiving, from the radio base station, an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically assign radio resources for each of the D2D data transmissions for the vehicle mobile device; and performing one or more D2D data transmissions based on the radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

[0257] Correspondingly, in one general aspect, features of the technology disclosed herein are directed to an integrated circuit for controlling a process of a radio base station, the process comprising: receiving, from a vehicle mobile device, assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes; configuring a plurality of semi-persistent radio resource configurations based on a transmission period of the different possible transmission periods of one or more D2D data transmissions, each of the plurality of semi-persistent radio resource configurations configured to be usable for transmitting at least one of the D2D data transmissions; transmitting information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically assign radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and transmitting an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

[0258] Correspondingly, in a general first aspect, the technology disclosed herein is characterized by a vehicle mobile terminal for transmitting periodic data to one or more receiving entities. The vehicle mobile terminal supports transmission of periodic data comprising one or more different data components to be transmitted with different possible transmission periods and / or different possible message sizes. A transmitter of the vehicle mobile terminal transmits information about the periodic data to a radio base station in charge of allocating radio resources to the vehicle mobile terminal. The transmitted information about the periodic data is such that it allows the radio base station to determine the different possible transmission periods and / or the different possible message sizes of the one or more data components of the periodic data. A receiver of the vehicle mobile terminal receives from the radio base station a plurality of semi-persistent radio resource configurations configured by the radio base station based on the received information about the periodic data. Each of the plurality of semi-persistent radio resource configurations is configured to be usable for transmitting at least one of the supported data components. The transmitter then indicates to the radio base station one or more of the data components to be transmitted by the vehicle mobile terminal. The receiver receives from the radio base station an activation command for activating one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for the vehicle mobile terminal to transmit each of the indicated data components. The transmitter then transmits the one or more data components to the one or more receiving entities based on the radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

[0259] Correspondingly, in a general first aspect, the technology disclosed herein is characterized by a radio base station for assigning radio resources to a vehicular mobile terminal for transmitting periodic data to one or more receiving entities. The vehicular mobile terminal supports transmission of periodic data comprising one or more different data components to be transmitted with different possible transmission periods and / or different possible message sizes. A receiver of the radio base station receives information from the vehicular mobile terminal about the periodic data to be transmitted by the vehicular mobile terminal to the one or more receiving entities. A processor of the radio base station determines the different supported data components, and the different possible transmission periods and / or different possible message sizes of the one or more data components. The processor configures a plurality of semi-persistent radio resource configurations based on the determined transmission periods and / or the determined message sizes. Each of the plurality of semi-persistent radio resource configurations is configured to be usable for transmitting at least one of the supported data components. A transmitter of the radio base station transmits information about the configured plurality of semi-persistent radio resource configurations to the vehicular mobile terminal. The receiver receives an indication from the vehicular mobile terminal of one or more of the data components to be transmitted by the vehicular mobile terminal. The processor then selects one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicular mobile terminal for periodically assigning radio resources for the vehicular mobile terminal to transmit each of the indicated data components. The transmitter is further configured to transmit an activation command to the vehicular mobile terminal to activate the selected one or more semi-persistent radio resource configurations for the vehicular mobile terminal.

[0260] Additional benefits and advantages of the disclosed embodiments will be apparent from the specification and drawings. The benefits and / or advantages can be separately provided by individual embodiments and need not be provided by each and every embodiment. One or more of the benefits and / or advantages can be provided in one or more embodiments described herein.

[0261] These general and specific aspects can be implemented using a system, a method, and a computer program, and any combination of a system, a method, and a computer program. BRIEF DESCRIPTION OF DRAWINGS

[0262] Example embodiments are described below in more detail with reference to the accompanying drawings.

[0263] Figure 1 An exemplary architecture of a 3GPP LTE system is shown,

[0264] Figure 2 An exemplary downlink resource grid of a downlink slot is shown for a subframe as defined for 3GPP LTE (Release 8 / 9),

[0265] Figure 3 How a Layer 2 link is established over PC5 for ProSe communication is schematically illustrated,

[0266] Figure 4 Fig. illustrates the use of transmission / reception resources for overlay (LTE) and underlay (D2D) systems,

[0267] Figure 5 Fig. illustrates the scheduling allocation for two UEs and transmission of D2D data,

[0268] Figure 6 Fig. illustrates D2D communication timing for UE autonomous scheduling mode 2,

[0269] Figure 7 Fig. illustrates D2D communication timing for eNB scheduling mode 1,

[0270] Figure 8 Fig. illustrates an exemplary architecture model for ProSe for non-roaming scenarios,

[0271] Figure 9 Fig. illustrates an exemplary composition of a CAM message,

[0272] Figure 10 Fig. illustrates transmission of several different CAM components with varying periodicity and message size for three different speed ranges,

[0273] Figure 11 Fig. illustrates transmission of three different CAM components and use of three SPS configurations for transmitting the CAM according to an exemplary implementation of the first embodiment,

[0274] Figure 12 Fig. also illustrates transmission of three different CAM components and use of three SPS configurations for transmitting the CAM according to another exemplary implementation of the first embodiment, wherein the radio resources allocated by the SPS configurations are combined together,

[0275] Figure 13 Fig. also illustrates transmission of three different CAM components and use of three SPS configurations for transmitting the CAM according to another exemplary implementation of the first embodiment, wherein the radio resources allocated by the corresponding SPS configurations are sufficient to transmit a complete CAM message, and

[0276] Figure 14 Fig. also illustrates transmission of three different CAM components and use of nine different SPS configurations for transmitting the CAM according to another exemplary implementation of the first embodiment, having assumed that the vehicle UE supports three different speed ranges,

[0277] Figure 15It is also illustrated the transmission of three different CAM components, as well as the usage of ten different SPS configurations for transmitting the CAM, according to another exemplary implementation of the first embodiment, already assuming that the vehicle UE supports three different speed ranges. DETAILED DESCRIPTION

[0278] A mobile station or mobile node or user terminal or user equipment is a physical entity within a communication network. A node can have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predetermined set of functions towards the node or other functional entities of the network. A node can have one or more interfaces that attach the node to a communication facility or medium through which the node can communicate. Similarly, a network entity can have logical interfaces that attach the functional entities to a communication facility or medium through which the network nodes can communicate with other functional entities or peer nodes.

[0279] The term "radio resources" used in claims and the application shall be construed broadly to refer to physical radio resources such as time-frequency resources.

[0280] The term "direct communication transmission" as used in this application shall be construed broadly to refer to a transmission directly between two user equipments, i.e. not via a radio base station (e.g. eNB). Correspondingly, a direct communication transmission is performed over a "direct sidelink connection", which is a term used for a connection established directly between two user equipments. For example, in 3GPP the terms D2D (device-to-device) communication or ProSe communication or sidelink communication are used. The term "direct sidelink connection" shall be construed broadly and can be understood in the context of 3GPP as the PC5 interface described in the background section.

[0281] The term "ProSe" or its unabbreviated form "Proximity Services" as used in this application applies in the context of proximity-based applications and services in LTE systems as exemplarily explained in the background section. Other terms such as "D2D" are also used in this context to refer to device-to-device communication for proximity services.

[0282] The term "vehicle mobile terminal" as used throughout the application shall be construed in the context of the new 3GPP study item V2X (Vehicle Communication) as explained in the background section. Correspondingly, a vehicle mobile terminal shall be construed broadly as a mobile terminal that is specifically installed in a vehicle (e.g. car, commercial truck, motorcycle, etc.) to perform vehicle communication, i.e. to communicate information related to the vehicle to other entities (such as vehicles, infrastructure, pedestrians) for purposes such as safety or driver assistance. Optionally, the vehicle mobile terminal can have access to information available in a navigation system (assuming it is installed in the car as well), such as map information, etc.

[0283] As explained in the background section, 3GPP has introduced a new study item for LTE- assisted vehicular communications, which shall exchange V2V traffic between various vehicular mobile terminals and other stations based on ProSe procedures. Moreover, V2V traffic for mode 1 sidelink assignment shall support semi-persistent radio resource assignment in order to reduce the amount of scheduling performed by the eNB. However, the current SPS mechanism is not adapted to V2V traffic and its characteristics. For example, for usual semi-persistent scheduling over Uu link (i.e. between eNB and UE), the eNB receives QCI information (QoS class identifier) from the MME (mobility management entity). The QCI information indicates that a certain bearer configured between the eNB and the UE is configured to transport VoIP traffic, so that the eNB is aware of the periodic traffic generated by the UE on this bearer. Then, the eNB can configure a SPS period by sending RRC signaling to the UE, configuring the UE with semi-persistent radio resource assignment. Then, when the UE needs to actually send VoIP data over this bearer and sends a corresponding buffer status report indicating that there is data to be sent for VoIP traffic, the eNB will send a PDCCH to the UE to activate the SPS configuration, the PDCCH message also indicating which radio resources the UE is allowed to use periodically (thus assigning a certain amount of radio resources). Correspondingly, the UE uses the SPS resources for periodically sending VoIP traffic.

[0284] However, the eNB is not aware of the type of traffic (e.g. periodicity or message size) that will be sent by a certain vehicular UE over the sidelink connection, so that the eNB cannot correctly determine the amount of resources to assign by semi-persistent radio resource assignment, and the periodicity of these semi-persistent radio resources.

[0285] Even if the eNB would receive in some way information about the traffic to be sent by a vehicular UE, it should be noted that the vehicular UE will have to send V2V traffic with different periodicity and / or different message size, which is significantly different from the type of VoIP traffic for which the current SPS mechanism is designed. Moreover, the periodicity of sending V2V traffic is variable, as it can change for example depending on the vehicular dynamics, such as the speed at which the vehicle is travelling. Therefore, the current standardized SPS mechanism is not sufficient to cope with these different V2V usage scenarios.

[0286] The inventors conceived the following exemplary embodiments to mitigate one or more of the above-mentioned problems.

[0287] Particular implementations of various embodiments will be implemented within the broad confines of the specifications given by the 3GPP standards and partly explained in the Background section, with particular key features added as explained below in relation to various embodiments. It should be noted that embodiments can advantageously be used for e.g. mobile communication systems such as the 3GPP LTE-A (Release 10 / 1 1 / 12 / 13) communication system (or higher releases) as described in the above Background section, but embodiments are not limited to their use in this particular exemplary communication network.

[0288] The explanations should not be understood to limit the scope of the present disclosure, but merely as examples to better understand embodiments thereof. A person skilled in the art should realize that the general principles of the present disclosure as stated in the claims can be applied to different situations and in ways not explicitly described herein. Several assumptions have been made for illustrative purposes, but these assumptions should not limit the scope of the following embodiments.

[0289] Various embodiments mainly provide an improved semi-persistent resource allocation procedure between the (vehicular) UE and the eNB responsible for allocating radio resources to the (vehicular) UE. Thus, other functionalities (i.e. functionalities which are not changed by various embodiments) can remain exactly as explained in the Background section, or can be changed without any consequences for various embodiments. This includes e.g. other procedures related to how the vehicular UE performs actual transmission of periodic data after it has been allocated suitable semi-persistent radio resources.

[0290] First embodiment

[0291] In the following, a first embodiment for solving the above-mentioned problems will be described in detail. Different implementations and variants of the first embodiment will also be explained.

[0292] Exemplarily, a vehicular UE is assumed which is installed in a vehicle and which is capable of performing vehicular communication based on the D2D framework as explained in the Background section of this application. However, as will be explained in more detail later on, the underlying principles of the present application are not limited to be applied by vehicular UEs only, but can also be implemented by regular (i.e. non-vehicular) UEs which e.g. transmit periodic data to an eNB via the Uu interface or to other UEs via the PC5 interface (sidelink connection). Nevertheless, for the following discussion, it is assumed that it is a vehicular UE which needs to periodically transmit V2V data.

[0293] It is further assumed that the vehicle UE transmits (broadcasts) periodic data to other (vehicle) UEs, although it is also possible to transmit the periodic data to other (vehicle) UEs (via the PC5 interface), its eNB (via the Uu interface), a road side unit (possibly via the PC5 interface) and / or other suitable stations interested in the periodic data transmitted by the vehicle UE; it can be assumed that the transmission from the vehicle UE is point-to-multipoint, reaching all receiving entities in its area.

[0294] The periodic data transmitted by the vehicle UE will be exemplified by the Cooperative Awareness Message (CAM), which is explained in detail in the background section. A characteristic of the CAM in relation to the present application is that the CAM is transmitted in a periodic manner. However, the CAM differs significantly from the usual VoIP use case of the semi-persistent scheduling scenario, because there are different and even varying transmission periods and / or different message sizes (i.e. the amount of data to be transmitted and for which the vehicle UE needs radio resources). VoIP exhibits a fixed period and a fixed message size, which can be handled by semi-persistent radio resource allocation.

[0295] It should be noted that the CAM is merely an example of such periodic data and that the present application can also be applied to other data types that can be standardized for vehicle or non-vehicle communication in the future. Especially for vehicle communication, it is very likely that a vehicle UE can have to periodically broadcast (status and attribute) data with different and / or even varying periods, so that messages with more or less data can have to be transmitted at different instants due to the different periods.

[0296] As will be explained in detail below, the CAM message is a proper example of such periodic data and will thus be used to explain the first embodiment and its variants, although the present application is not limited thereto, as just mentioned.

[0297] There are different CAM components (e.g. CAM HF, CAM LF, the certificate will be a CAM component on which the invention will be explained in the following) which need to be periodically broadcasted by the vehicle UE but with different periodicities. The following main assumption is made: At a certain time instant, the vehicle UE only sends / broadcasts one CAM message, however, said CAM message comprises different CAM components which will be sent at that time instant (i.e. CAM components which, although having different periodicities, coincide at that time instant). In other words, if the vehicle UE is to send different CAM components at the same time (SC period on the PC5 interface), the different CAM components are piggybacked together to form a single CAM message which is then sent. For the sake of practical work, the periodicities of the different CAM components need to be coordinated (i.e. to be a multiple of each other) so that the different CAM components indeed coincide at the same certain time instant. Thus, a single CAM is sent in a periodic manner, it has a single periodicity (which is given by the highest sending rate of the CAM components (e.g. CAM HF component) to be sent), but with different content, thus message size (i.e. different CAM components are included in the single CAM message at different time instants) also periodically varies (see e.g. Figure 10 and related description). Thus, the radio resource allocation mechanism needs to allocate different amounts of radio resources at different time instants.

[0298] Alternatively, the different CAM components with different periodicities can also be sent as separate CAM messages. This can be disadvantageous in view of the need for more radio resources, since each separate CAM message can need to include at least a header and can also include a basic container (see Figure 9 and related description), which is avoided in the first alternative by piggybacking the CAM components together. However, providing separate CAM messages has the advantage that the need to coordinate the different periodicities of the individual CAM components can be avoided, i.e. the periodicities of the individual CAM components can be freely defined. In this case, the CAM messages have different periodicities and different message sizes.

[0299] It should be noted that the 3GPP standardization has not yet fully agreed on the following: the sending rate of the different CAM components, whether piggybacking will be optional or mandatory, how exactly the different CAM components will be sent. In any case, this can also change in future releases. The underlying principles of the invention apply to any one of these cases, even though slight adaptations can have to be applied to address these changes.

[0300] In the following, the main assumption will be made that at a certain time instant, the vehicle UE only sends one CAM message, which means that the different CAM components will form a single CAM message.

[0301] Furthermore, the required transmission periodicity of the CAM component can be expected to vary rapidly over time as a function of the vehicle dynamics, such as speed, heading and / or angle; other factors can be defined in the future.

[0302] In summary, the (vehicle) UE will transmit periodic data (e.g. CAM) to other receiving entities (e.g. other vehicle stations). In order to transmit the periodic data, the vehicle UE requires radio resources which can be assigned, e.g. by the eNodeB, e.g. according to ProSe Mode 1 radio resource assignment as explained in the background section. According to a first embodiment, the eNodeB assigns semi-persistent radio resources to the vehicle UE, thereby allowing the vehicle UE to periodically transmit pending periodic data.

[0303] In order to provide a brief overview, the first embodiment can be conceptually divided into a preparation phase and an execution phase. In the preparation phase, the eNodeB will configure different SPS configurations for later transmission of periodic data supported by the vehicle UE and thus can be transmitted by the vehicle UE in the future. The vehicle UE will be configured with various different SPS configurations which can be activated during the execution phase as required. It can be assumed that the execution phase starts when the vehicle UE starts transmitting part or all of the supported periodic data. Correspondingly, a specific SPS configuration among the previously prepared SPS configurations is activated in the UE and then used by the vehicle UE for transmitting the pending periodic data. During the execution phase, the message size or the periodicity of the pending periodic data can change such that a different SPS configuration among the previously prepared SPS configurations has to be activated in the vehicle UE in order to still be able to transmit the periodic data with a different periodicity or with a different message size.

[0304] The preparation phase will now be explained in more detail. In order for the eNodeB to be able to set up suitable SPS configurations for the periodic data supported by the UE, the eNodeB requires information about the periodic data which can be transmitted by the vehicle UE in the future. Typically, an SPS configuration assigns a certain amount of radio resources in a periodic manner, i.e. at periodic time instants, which in turn depends on the amount of data (e.g. the size of a CAM message) which the UE needs to transmit. Correspondingly, the vehicle UE transmits information about the periodic data to the eNodeB, such that the eNodeB is able to determine one or more different possible periodicities and / or different possible message sizes which can be transmitted by the vehicle UE in the future. Having learned this information, the eNodeB is then able to configure a plurality of different SPS configurations in a way that one or more of these SPS configurations are later activated for the vehicle UE, such that the vehicle UE is able to actually transmit one or more of the supported periodic data using the radio resources periodically assigned by the activated SPS configuration.

[0305] After the plurality of SPS configurations has been thus set up, the eNodeB provides the vehicle UE with corresponding information about the plurality of SPS configurations, so that the vehicle UE is aware of the plurality of SPS configurations that can be activated in the future. Thus, the eNodeB and the vehicle UE are prepared for handling the transmission of one or more supported periodic data.

[0306] The execution phase will now be explained in more detail. It is then assumed that the vehicle UE will eventually want to transmit some or all of the CAM data components, and thus needs (semi-persistent allocated) radio resources to perform the transmission. Correspondingly, the vehicle UE will inform the eNB about which CAM components it wants to transmit, and the eNB in response selects one or more SPS configurations among the previously prepared SPS configurations that will allocate suitable radio resources to the vehicle UE in order to transmit the whole of the now pending CAM components. The eNB will then activate the selected one or more SPS configurations in the UE correspondingly, e.g. by sending a suitable activation command.

[0307] The vehicle UE activates the particular SPS configuration correspondingly as instructed by the eNodeB, and thus can use the periodic radio resources scheduled by the activated SPS configuration in order to transmit the pending one or more CAM data components to other (vehicle) UEs.

[0308] As mentioned above, according to the first embodiment SPS resources can be allocated to the vehicle UE even if the data to be transmitted by the vehicle UE can have a changing periodicity and / or a changing message size. Thus, the signaling overhead on the Uu link between the eNodeB and the UE can be reduced, which otherwise would be necessary to repeatedly perform dynamic radio resource allocation for each SC period (see e.g. the ProSe Mode 1 explanation in the background section). Furthermore, there is no need to send a buffer status report from the UE to the eNB used by the vehicle UE to indicate that (periodic) data is pending for transmission to trigger the eNodeB to allocate dynamic resources each time a periodic data comes to the UE side.

[0309] Figure 11 An exemplary implementation according to the first embodiment is exemplarily illustrated that activates three different SPS configurations to allow the transmission of three different CAM components (a certificate, a CAM LF component and a CAM HF component). For this exemplary implementation of the first embodiment, it is assumed that one SPS configuration is configured for one particular CAM data component. Correspondingly, a vehicle UE that wants to transmit three different CAM components can use the periodic radio resources allocated by SPS configuration 1 to transmit the CAM HF component, can use the periodic radio resources allocated by SPS configuration 2 to transmit the CAM LF component, and can use the periodic radio resources allocated by SPS configuration 3 to transmit the certificate.

[0310] Depending on whether the different CAM components are transmitted in one message or in separate messages, different SPS configurations will be combined by the vehicle UE to be able to transmit a larger combined CAM message, or can be used separately from each other to transmit separate CAM messages.

[0311] The following will be a more specific implementation of the first embodiment.

[0312] In the broad implementation of the first embodiment, it is simply assumed without further detail that the vehicle UE will support transmission of periodic data, including one or more different data components to be transmitted with different possible transmission periods and / or different possible transmission message sizes. As previously mentioned, the challenge posed to the SPS assignment mechanism of the first embodiment is that the transmission of vehicle data involves different possible periods and / or different message sizes. This will be explained in more detail based on the CAM message introduced in the background section.

[0313] According to one possible exemplary scenario, the vehicle UE supports transmission of several CAM components (e.g. CAM HF component, CAM LF component and security certificate). Correspondingly, the possible message sizes differ depending on which CAM components are transmitted in the CAM message. The following table gives an overview of the different possible message sizes:

[0314]

[0315] For the above table, it is assumed that the different CAM components transmitted at the same time form one single CAM message, such that the CAM LF component and the CAM security certificate are piggybacked to the basic CAM HF component transmitted at the highest transmission rate. Accordingly, the message size will vary depending on the time instant, as listed on the right side column of the table and as exemplarily illustrated in Figure 11 the different periods of the assumed CAM components, Figure 11 the transmission of the CAM HF component + CAM security certificate is not shown; in that respect, see Figure 10 the middle part of

[0316] The different CAM components are to be transmitted with different periods, such that each possible CAM message to be transmitted at a certain time instant will have to be transmitted with a different period, as exemplarily shown in the following table:

[0317]

[0318] The values of the transmission period assumed above actually refer to the period of the CAM component with the lowest transmission rate in the CAM message (e.g. for a CAM message comprising a CAM HF and a CAM LF component, the CAM LF component is 500 ms). The indicated transmission period should not be understood as the transmission period of a specific CAM message. For example, a CAM message comprising a CAM HF and a CAM LF component is not actually transmitted every 500 ms (but every 1000 ms, see Figure 11 ).

[0319] The values for the transmission period exemplarily assumed in the above table are those assumed for a single vehicle speed range of > 144 km / h, which is assumed to be the only one vehicle speed range supported by the vehicle UE.

[0320] According to another possible exemplary scenario, the vehicle UE supports the transmission of only one CAM component (e.g. the CAM HF component), thus having a fixed size of 122 bytes expected (see above table), and a fixed period of 100 ms expected (see above table). However, the special characteristic of the V2V data is that the period of the different CAM components can vary with the vehicle dynamics (e.g. the speed at which the vehicle UE is travelling). Thus, even if the vehicle UE supports the transmission of only one CAM component, the period in which this one CAM component is transmitted can vary over time, again leading to the SPS allocation mechanism to consider several periods. This is exemplified in the following table.

[0321]

[0322]

[0323] According to another possible exemplary scenario, the vehicle UE supports the transmission of various CAM components (e.g. all three CAM components: CAM HF, CAM LF and Security Certificate), and in addition should support several speeds (ranges). The resulting varying periods and message sizes will become apparent from the following table.

[0324]

[0325] As exemplified above, there can be many different combinations of CAM components (left column of the table above), resulting in different possible CAM message sizes (e.g. 122 bytes, 182 bytes, 299 bytes or 239 bytes) and resulting in different possible periodicities, depending on the particular CAM components and / or possibly depending on the supported speed (range) for the vehicle UE (e.g. 100ms, 200ms, 300ms, 500ms, 600ms, 1000ms, 1200ms). The SPS configuration configured by the eNB in the preparation phase needs to take this into account and should match the resulting CAM message transmission periodicity and / or the resulting CAM message size supported by the vehicle UE, so that a suitable SPS configuration can be activated later on to enable the vehicle UE to transmit any (combination) of the supported periodic data.

[0326] The eNodeB prepares various different SPS configurations, as will be exemplified for the above selected example. In particular, first, for simplicity, it is assumed that the vehicle UE supports the transmission of several CAM components, but only supports one speed range, e.g. the highest speed range > 144 km / h, so that although several different periodicities are to be considered, the periodicity itself does not change over time (e.g. due to speed changes).

[0327]

[0328] In the above exemplary implementation of the first embodiment, three different SPS configurations 1, 2 and 3 are configured by the eNodeB, so that there is one separate SPS configuration matching each possible CAM component supported by the vehicle UE for transmission. It should be noted that for the possible combination of CAM HF component and CAM safety certificate, no separate SPS configuration is needed in this particular example, in view of the fact that this particular combination does not occur due to the exemplary periodicity assumed for the separate CAM components.

[0329] SPS configuration 1 assigns specific radio resources sufficient for transmitting the basic CAM HF component of 122 bytes every 100 ms, which is the periodicity of the CAM HF component. Correspondingly, the UE will use the periodic radio resources assigned by SPS configuration 1 in order to transmit a CAM message comprising the CAM HF component.

[0330] Furthermore, SPS configuration 2 allocates specific radio resources sufficient to transmit an additional (slightly larger) CAM LF component of 60 bytes every 500 ms, which is the period of the CAM LF component. Correspondingly, the UE will use the periodic radio resources allocated by SPS configuration 2 in order to transmit a CAM message including the CAM LF component. Furthermore, SPS configuration 3 allocates specific radio resources sufficient to transmit an additional (slightly larger) security certificate of 117 bytes every 1000 ms, which corresponds to the periodicity of the security certificate. Correspondingly, the UE will use the periodic radio resources allocated by SPS configuration 3 in order to transmit a CAM message including the security certificate.

[0331] Figure 12 Fig. 1 illustrates the use of the three SPS configurations for transmitting CAM messages by a vehicle UE as exemplarily assumed above according to an exemplary implementation of the first embodiment. As apparent from Fig. 1, the three SPS configurations match the three different data components to be transmitted by the vehicle UE. The dashed rectangles enclosing multiple data components to be transmitted at the same time should indicate that these different data components are transmitted as one CAM message as exemplarily assumed above. As apparent from Fig. 1, the CAM HF component is transmitted every 1000 ms, the CAM LF component is transmitted every 500 ms, and the security certificate is transmitted every 1000 ms. Figure 12 Figure 12 As apparent from Fig. 1, at those time instants where several CAM components are to be transmitted within one CAM message, the vehicle UE combines the radio resources allocated by the multiple SPS configurations in order to have sufficient radio resources available for transmitting the entire CAM message (i.e. including the multiple CAM components). For example, when transmitting the CAM HF component together with the CAM LF component, the radio resources allocated via SPS configurations 1 and 2 are combined (i.e. summed up, used together) in order to have sufficient radio resources available for transmitting. Similarly, when transmitting the CAM HF component together with the CAM LF component and the security certificate, the radio resources allocated via SPS configurations 1, 2 and 3 are combined in order to have sufficient radio resources available for transmitting the entire combined CAM message.

[0332] As just explained, it can be necessary for the vehicle UE to combine the radio resources allocated by different SPS configurations for those time instants where a larger combined CAM message is to be transmitted. According to the following alternative implementation of the first embodiment, this combination of radio resources allocated separately by SPS configurations is no longer required. Instead, the individual SPS configurations are configured in such a way that they already take into account the resulting size of a single CAM message. The following table will exemplarily illustrate this alternative implementation of the first embodiment according to the above discussion.

[0333]

[0334]

[0335] ​As apparent from the table, the difference of the SPS configurations with the previous embodiments is that the amount of radio resources allocated by the individual SPS configurations is larger, so that larger CAM message sizes are considered when several CAM components are transmitted in one CAM message.

[0336] With Figure 12 Correspondingly, Figure 13 Fig. 1 illustrates how a vehicle UE uses different SPS configurations for transmitting periodic CAM data (components). At those instants when the vehicle UE will transmit several CAM components within one CAM message, the vehicle UE shall select among the activated SPS configurations the SPS configuration that provides sufficient radio resources to transmit the larger CAM message. As in the previous exemplary embodiments of the first embodiment, the vehicle UE will select SPS configuration 1 for transmitting a CAM message comprising only a CAM HF component. On the other hand, when the CAM HF component is transmitted together with a CAM LF component, 182 bytes of radio resources are needed to transmit in total, so that the vehicle UE will select SPS configuration 2 and will use the specific radio resources allocated by SPS configuration 2 for transmitting said CAM message comprising the CAM HF component as well as the CAM LF component. Correspondingly, when the CAM HF component is transmitted together with a CAM LF component as well as a security certificate, 299 bytes of radio resources are needed to transmit in total, so that the vehicle UE will select SPS configuration 3. Thus, the vehicle UE will use the specific radio resources allocated by SPS configuration 3 for transmitting said CAM message comprising the three components.

[0337] The embodiments of the first embodiment according to Figure 12 and Figure 13 discussed above can also be applied to the more complex case that the vehicle UE also supports several speed ranges, e.g. three hypothetical speed ranges: > 144, between 72 and 144, and between 48 and 72, resulting in additional different periodicities that shall be supported for the individual CAM components.

[0338] The following table assumes that the radio resources allocated by the different SPS configurations can be combined by the vehicle UE to collect sufficient radio resources to be able to transmit a combined CAM message comprising several data components (see discussion for Figure 12 ).

[0339]

[0340]

[0341] As will be apparent from the above table, the eNodeB in the preparation phase is assumed to configure 9 separate SPS configurations allocating radio resources in appropriate periodicities, so that the vehicle UE is able to transmit the corresponding CAM components in a periodic manner when one or more SPS configurations are activated later on.

[0342] Depending on the current speed of the vehicle UE, the eNodeB will configure the vehicle UE to have activated SPS configurations 1, 2 and 3 when the speed > 144 km / h, or SPS configurations 4, 5 and 6 when the speed is between 72 and 144 km / h, or SPS configurations 7, 8 and 9 when the speed is between 48 and 72 km / h.

[0343] Figure 14 It is illustrated how the vehicle UE can use the 9 separate SPS configurations to periodically transmit CAM messages of different sizes. Figure 14 The upper part of the table (i.e. referring to speeds > 144 km / h) basically corresponds to Figure 12 and will therefore not be explained again. For the speed range between 72 and 144 km / h, Figure 14 It is illustrated how the vehicle UE combines the radio resources allocated by the activated SPS configurations 4, 5 and 6 to be able to transmit CAM messages of different sizes. Specifically, a CAM message comprising the CAM HF component as well as the CAM LF component can be transmitted by the vehicle UE by combining the radio resources allocated by SPS configurations 4 and 5. A CAM message comprising all three components (CAM HF, CAM LF, security certificate) can be transmitted by the vehicle UE by combining and using the radio resources allocated by SPS configurations 4, 5 and 6. A CAM message comprising the CAM HF component and the security certificate can be transmitted by the vehicle UE by combining and using the radio resources allocated by SPS configurations 4 and 6.

[0344] For the speed range between 48 and 72 km / h, Figure 14 It is illustrated how the vehicle UE combines the radio resources allocated by the activated SPS configurations 7, 8 and 9 to be able to transmit CAM messages of different sizes. Specifically, a CAM message comprising the CAM HF component as well as the CAM LF component can be transmitted by the vehicle UE by combining the radio resources allocated by SPS configurations 7 and 8. A CAM message comprising all three components (CAM HF, CAM LF, security certificate) can be transmitted by the vehicle UE by combining and using the radio resources allocated by SPS configurations 7, 8 and 9.

[0345] In the following, the first embodiment explained in connection with Figure 13 Alternative implementations of the first embodiment explained in the following will now also be extended to vehicle UEs supporting several speed ranges.

[0346]

[0347]

[0348] Figure 15 Fig. illustrates the corresponding use of different SPS configurations by the vehicle UE for transmitting the various possible CAM messages. Figure 15 The upper part (for speeds > 144 km / h) basically corresponds to Figure 13 and will not be explained again. In order to support the transmission of all possible CAM components for the speed range between 72 and 144 km / h, four different SPS configurations are configured by the eNodeB. Unlike for the case of speed range > 144 km / h, the vehicle UE does indeed have to transmit a CAM message including the CAM HF component and the CAM security certificate. In this alternative embodiment of the first embodiment, the eNodeB therefore has to configure a separate SPS configuration for this possible CAM message, i.e. an SPS configuration 7 allocating specific radio resources sufficient to transmit 239 bytes every 1000 ms. This SPS configuration 7 is not necessary in the previous embodiment of the first embodiment, as the radio resources of SPS configurations 4 and 6 can be flexibly combined in order to allocate sufficient (but not too much) resources for transmitting a CAM message including the CAM HF component as well as the security certificate (see Figure 14 ).

[0349] As repeatedly mentioned, several SPS configurations are prepared by the eNodeB to support different possible speed ranges that the UE can travel (as an example of vehicle dynamics affecting the periodicity of various CAM data components). In this case, it is also necessary to inform the eNB about the possible speed ranges supported by the vehicle UE, as these will affect the different periodicities to be considered when preparing multiple SPS configurations. One option is to transmit explicit information about the speed ranges supported by the vehicle UE to the eNB, e.g. together with or separately from the information about the periodic data, in order to enable the eNB to determine therefrom the resulting different periodicities of the periodic data components to be considered when preparing multiple SPS configurations. Another option is that the vehicle UE has already transmitted the various possible periodicities, which also include the periodicities of the supported speed ranges, so that the UE does not have to additionally inform the eNB about the supported speed ranges; assuming that the eNB has access to specific information allowing this association, such as standardized definitions of the periodicities of CAM messages and components for different speed ranges, the eNB can infer the supported speed ranges from the reported different periodicities.

[0350] Furthermore, when the UE wants to actually start transmitting periodic data, the UE should inform the eNB about its current speed (or the speed range it is in) so that the eNB can select and activate those SPS configurations that are prepared for the indicated speed range the vehicle UE is currently experiencing. The information about the current speed can be transmitted, e.g., by the vehicle UE together with the indication of which data components the vehicle UE wants to transmit or separately. For example, the exemplary implementation of the first embodiment provides that this indication is a buffer status report indicating that data is pending in the corresponding buffer in the UE for a particular logical channel group. Correspondingly, the information about the current speed of the vehicle UE can also be transmitted within the buffer status report.

[0351] Furthermore, as mentioned before, the periodicity of the CAM data component can depend on the vehicle dynamics such as the speed, however it can change over time. Therefore, a further implementation of the first embodiment allows to change the activated SPS configuration depending on the current vehicle dynamics, e.g., the speed of the vehicle UE. In this regard, the vehicle UE can monitor its own speed and can determine whether the speed range has changed compared to the speed range it was in previously. In this case, the vehicle UE can inform the eNodeB about this change of the speed range. Alternatively, the vehicle UE can periodically transmit information about its current speed to the eNodeB so that the eNodeB itself can determine when a particular vehicle UE changes the speed range related to the SPS configuration. In any case, the change of the speed range can thus trigger the eNodeB to select and activate a different SPS configuration that is prepared for the indicated speed range than the previously activated SPS configuration. The vehicle UE receiving such an activation command for the changed SPS configuration will no longer use the previously activated SPS configuration but the newly activated SPS configuration.

[0352] According to a further alternative implementation of the first embodiment, instead of transmitting the current speed or the currently changed speed range to the eNodeB, the vehicle UE can actually identify the corresponding SPS configuration that is required for the changed speed range when it determines that it has changed a particular speed range and can transmit a request to the eNodeB to use these new SPS configurations due to the change of the speed range. In turn, the eNodeB receives this request and can decide whether it should follow the request or not. Correspondingly, the eNodeB can determine that the change of the SPS configuration is ordered, thus the eNodeB correspondingly transmits a response to the request in order to activate the requested SPS configuration. Therefore, the vehicle UE will no longer use the previously activated SPS configuration but now the newly activated SPS configuration.

[0353] When changing the SPS configuration in the vehicle UE as just described above due to a change in the vehicle dynamics (e.g. speed), according to one possible implementation of the first embodiment, the vehicle UE can always start by sending all CAM components (i.e. a CAM message comprising all CAM components) in order to avoid not sending some of the components due to frequent changes in the speed and thus frequent changes in the SPS configuration.

[0354] As described above, the vehicle UE sends information to the eNB about the supported periodic data that the vehicle UE can have to transmit in the future. As will be explained in detail with reference to the following implementations of the first embodiment, this can be implemented in various ways. According to an exemplary implementation of the first embodiment, the vehicle UE can explicitly inform the eNodeB about different possible periodicities and / or different possible message sizes of the CAM messages / components that the vehicle UE supports and thus can have to actually transmit in the future. For example, the information about the periodic data can thus comprise a list of possible periodicities and / or possible CAM message sizes supported by the vehicle UE. Thus, the eNodeB is able to prepare a suitable SPS configuration for the various different supported periodicities and / or message sizes.

[0355] According to a variant of this implementation of the first embodiment, the information about the periodic data can be sent in one message or in at least two separate messages. In particular, the information about the possible periodicities and possible message sizes can be sent within one message, e.g. a SidelinkUEInformation message based on the current specification in the standard to indicate sidelink information to the eNodeB (e.g. the frequency at which the UE is interested in transmitting sidelink communications and the sidelink communication transmission destinations for which the UE requests to be allocated dedicated resources) (see 3GPP standard TS 36.331 v13.0.0 section 6.2.2, which is hereby incorporated by reference). In the following, an exemplary extended SidelinkUEInformation message according to this implementation of the first embodiment is defined.

[0356] SidelinkUEInformation message

[0357]

[0358]

[0359] The additional elements in the SidelinkUEInformation message of this implementation, which exemplarily introduces the first embodiment, are in bold and are also boxed above. It is evident from this that there is a period field that allows indication of various different periods (such as the period mentioned above for the CAM message). Similarly, a message size field is provided, which allows indication of various different message sizes, each having a value between 1 and 300 bytes. Optionally, a service type field allows the UE to inform the eNodeB whether the data is periodic or non-periodic.

[0360] Instead of indicating the message size along with possible periods, according to another variation of the first embodiment, the message size (i.e., the amount of data the UE wants to send) is sent along with a buffer status report indicating that data is waiting to be sent by the vehicle UE. In this case, in one example of the preparation phase, the eNodeB will only receive information about possible different periods, but not about possible different message sizes, and will therefore continue to prepare different SPS configurations based on the information about possible different periods. For example, the multiple SPS configurations prepared by the eNodeB will be different in terms of periods, but not in terms of which and how many radio resources the SPS configuration will allocate. Then, when the vehicle UE actually wants to start sending one or more of the possible data components, the corresponding buffer will be filled, thereby triggering the sending of a buffer status report to the eNodeB, and on this basis, the eNodeB can actually determine the amount of data the UE wants to send for one or more possible data components. In response, the eNodeB will select and activate the corresponding appropriate SPS configuration (with the corresponding appropriate period), and then activate the selected SPS configuration for the vehicle UE, while indicating for each activated SPS configuration which resources are allocated by the corresponding activated SPS configuration.

[0361] In other words, combined with the previous Figures 11 to 15 The difference in interpretation lies in this particular variant of the first embodiment, where the eNodeB has not yet specified radio resources (e.g., defining SPS configuration 1 sufficient to transmit 122 bytes of radio resources), but only the period. For example, the eNodeB could prepare SPS configuration 1 to support CAM HF components transmitted by a vehicle UE at a period of 100ms (assuming a speed range >144km / h); similarly, this applies to other SPS configurations. Figure 12 In this hypothetical scenario, the eNodeB would therefore prepare three different SPS configurations, namely, for three cycles of 100ms, 500ms, and 1000ms respectively. For... Figure 14 In the hypothetical scenario, the eNodeB will prepare nine different SPS configurations, three for each speed range.

[0362] According to another exemplary implementation of the first embodiment, in addition or instead of sending information about different possible transmission periods and / or different possible message sizes, the vehicle UE can inform the eNodeB about specific data components that the vehicle UE is supported to transmit. For example, the information about periodic data can thus comprise a list identifying data components that the vehicle UE is supported to transmit in the future. The eNodeB has access to information about possible periods and message sizes associated with these identified data components; for example, 3GPP standardization can explicitly define sizes and periods for different possible CAMs and their components. In this way, the eNodeB is thus able to prepare suitable SPS configurations for the various different supported periods and / or message sizes.

[0363] While not specified in detail above, the activation command sent by the eNodeB to the vehicle UE to activate the selected SPS configuration can exemplarily be implemented as a message sent via PDCCH physical downlink control channel. For example, in a similar way as the currently specified SPS mechanism, the eNodeB can send one or more DCIs to activate one or more of the previously configured SPS configurations. In one example, a new C-RNTI can be used for the sidelink activation / deactivation DCI, as the UE needs to know that the DCI is for sidelink SPS, and not for Uu SPS or Uu link dynamic assignment. As mentioned above, for the specific implementation of the first embodiment, the PDCCH message can also identify the specific radio resources that the UE should use for the activated SPS configuration.

[0364] While not specified in detail above, after the multiple SPS configurations have been determined, the eNodeB should inform the UE about the multiple SPS configurations. This can for example be implemented as an RRC message, such as sps-ConfigSidelink in the radioResourceConfigDedicated message. The current SPS configuration for Uu link is sent in the radioResourceConfigDedicated message. To indicate the SPS configuration for sidelink, a new element can be created as sps-ConfigSidelink, which can also be sent in the radioResourceConfigDedicated message. As mentioned above, the multiple SPS configurations configured by the eNodeB in the preparation phase can for example identify both the period and the radio resources, or can only identify the period (the radio resources can then be identified together with the activation command sent from the eNodeB to the UE).

[0365] Although the implementation of the first embodiment has been explained based on a vehicle UE communicating with other vehicle UEs over a sidelink connection, the underlying principles of the first embodiment can also be applied to transmitting vehicle data between a vehicle UE and, e.g., an eNodeB over a Uu interface, or between a vehicle UE and a road side unit over, e.g., a PC5 interface.

[0366] Furthermore, although the implementation of the first embodiment has been explained based on a vehicle UE, the underlying principles of the first embodiment can also be performed by a "regular" UE communicating with an eNB or other "regular" or vehicle UEs over a sidelink connection.

[0367] According to embodiments of the present disclosure, at least the following vehicle mobile terminal and radio base station are disclosed.

[0368] According to a vehicle mobile terminal for transmitting periodic data to one or more receiving entities according to the present disclosure, the vehicle mobile terminal supports transmission of periodic data comprising one or more different data components to be transmitted with different possible transmission periodicities and / or different possible message sizes, the vehicle mobile terminal comprising: a transmitter transmitting information about the periodic data to a radio base station responsible for allocating radio resources to the vehicle mobile terminal, the transmitted information about the periodic data allowing the radio base station to determine the different possible transmission periodicities and / or different possible message sizes of the one or more data components of the periodic data, a receiver receiving from the radio base station a plurality of semi-persistent radio resource configurations configured by the radio base station based on the received information about the periodic data, each of the plurality of semi-persistent radio resource configurations being configured for being usable for transmitting at least one of the supported data components, the transmitter further indicating to the radio base station one or more of the data components to be transmitted by the vehicle mobile terminal, the receiver further receiving from the radio base station an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for the vehicle mobile terminal to transmit each of the indicated data components, and the transmitter further transmitting the one or more data components to the one or more receiving entities based on the radio resources and transmission periodicity configured by the activated one or more semi-persistent radio resource configurations.

[0369] According to the vehicle mobile terminal of the present disclosure, the transmitted information about periodic data comprises information about different possible transmission periods and / or different possible message sizes for one or more data components, optionally, information about message sizes for at least one data component to be transmitted by the vehicle mobile terminal is transmitted by the vehicle mobile terminal together with a buffer status report indicating that data is waiting to be transmitted for one data component, or information about different data components, allowing the radio base station to determine different possible transmission periods and / or different possible message sizes based on the received information about different possible data components.

[0370] According to the vehicle mobile terminal of the present disclosure, the transmitter further transmits information about a vehicle parameter, such as speed, supported by the vehicle mobile terminal to the radio base station, the information about the vehicle parameter being usable by the radio base station for determining different possible transmission periods for one or more supported data components, and the transmitter further transmits information about a current vehicle parameter experienced by the vehicle mobile terminal to the radio base station, the information about the current vehicle parameter being usable by the radio base station for selecting one or more of the plurality of semi-persistent radio resource configurations to activate, optionally, the information about the current vehicle parameter is transmitted together with an indication that one or more data components are to be transmitted by the vehicle mobile terminal.

[0371] According to the vehicle mobile terminal of the present disclosure, when one of the vehicle parameters changes more than a predetermined threshold, the transmitter further transmits information about the changed vehicle parameter to the radio base station, and the receiver in turn receives from the radio base station another activation command to activate other semi-persistent radio resource configurations than the previously activated semi-persistent radio resource configuration, or when one of the vehicle parameters changes more than a predetermined threshold, the transmitter further requests from the radio base station activation of other semi-persistent radio resource configurations than the previously activated semi-persistent radio resource configuration, and the receiver in turn receives from the radio base station another activation command to activate the other requested semi-persistent radio resource configurations than the previously activated semi-persistent radio resource configuration, and the transmitter further transmits one or more data components based on radio resources and transmission periods configured by the activated other semi-persistent radio resource configurations, optionally, the other activation command is received in a message via a physical downlink control channel, PDCCH.

[0372] According to the vehicle mobile terminal of the present disclosure, information on periodic data is transmitted within one message or information on periodic data is transmitted within at least two separate messages, optionally information on different possible periods of one or more supported data components is transmitted within a first message and information on the message size of at least one data component to be transmitted by the vehicle mobile terminal is transmitted together with a buffer status report by the vehicle mobile terminal, the buffer status report indicating that data of one data component is waiting for transmission.

[0373] According to the vehicle mobile terminal of the present disclosure, each of the received plurality of semi-persistent radio resource configurations identifies a radio resource and a period suitable for transmitting at least one of the supported data components, optionally the plurality of semi-persistent radio resource configurations is received in a message of a radio resource control, RRC, protocol or the period for transmitting at least one of the data components and information on the radio resource that can be used by the vehicle mobile terminal for transmitting at least one of the data components is received together with an activation command for activating one or more of the plurality of semi-persistent radio resource configurations, optionally the activation command and the information on the radio resource are received in a message via a physical downlink control channel, PDCCH.

[0374] According to the vehicle mobile terminal of the present disclosure, the data components to be transmitted at the same time are transmitted as one message or as separate messages.

[0375] According to the vehicle mobile terminal of the present disclosure, the receiving entity comprises other vehicles or non-vehicle mobile terminals and the periodic data is transmitted via a sidelink connection and / or the receiving entity comprises a radio base station and the periodic data is transmitted via a radio connection.

[0376] According to the vehicle mobile terminal of the present disclosure, the plurality of semi-persistent radio resource configurations is configured such that there is one semi-persistent radio resource configuration for each data component having a certain message size and a certain transmission period or the data components to be transmitted at the same time are transmitted as one message and the plurality of semi-persistent radio resource configurations is configured such that there is one semi-persistent radio resource configuration for each possible message comprising one or more data components to be transmitted by the vehicle mobile terminal, optionally the transmitter transmits a message comprising one or more data components based on the activated semi-persistent radio resource configuration corresponding to the included data components of the message to be transmitted.

[0377] A radio base station for assigning radio resources to a vehicular mobile terminal for transmitting periodic data to one or more receiving entities according to the present disclosure, the vehicular mobile terminal supporting transmission of periodic data comprising one or more different data components to be transmitted with different possible transmission periods and / or different possible message sizes, the radio base station comprising: a receiver receiving from the vehicular mobile terminal information about periodic data to be transmitted by the vehicular mobile terminal to one or more receiving entities, a processor determining different supported data components and different possible transmission periods and / or different possible message sizes of the one or more data components, the processor configuring a plurality of semi-persistent radio resource configurations based on the determined transmission periods and / or based on the determined message sizes, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the supported data components, a transmitter transmitting to the vehicular mobile terminal information about the configured plurality of semi-persistent radio resource configurations, the receiver further receiving from the vehicular mobile terminal an indication of one or more of the data components to be transmitted by the vehicular mobile terminal, the processor further selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicular mobile terminal for periodically assigning radio resources for the vehicular mobile terminal to transmit each of the indicated data components, and the transmitter further transmitting to the vehicular mobile terminal an activation command to activate the selected one or more semi-persistent radio resource configurations for the vehicular mobile terminal.

[0378] The radio base station according to the present disclosure, the received information about periodic data comprises: information about different possible transmission periods and / or different possible message sizes of one or more data components, optionally, information about message sizes of at least one data component to be transmitted by the vehicular mobile terminal is received from the vehicular mobile terminal together with a buffer status report indicating that data is waiting to be transmitted for one data component, or information about different data components, the processor further determines different possible transmission periods and / or different possible message sizes based on the received information about different possible data components.

[0379] The radio base station according to the present disclosure, the receiver further receives from the vehicular mobile terminal information about a vehicular parameter such as speed supported by the vehicular mobile terminal, the processor further determines different possible transmission periods of the one or more supported data components based on the received information about the vehicular parameter, and the receiver further receives from the vehicular mobile terminal information about a vehicular parameter currently experienced by the vehicular mobile terminal, the processor further selects one or more of the plurality of semi-persistent radio resource configurations to be activated based on the received current vehicular parameter, optionally, information about the current vehicular parameter is received from the vehicular mobile terminal together with an indication of one or more data components to be transmitted by the vehicular mobile terminal.

[0380] According to the radio base station of the present disclosure, the receiver receives information on a changed vehicle parameter from the vehicle mobile terminal, and the processor selects, based on the changed vehicle parameter, other semi-persistent radio resource configuration, other than the semi-persistent radio resource configuration previously selected and activated, and the transmitter transmits another activation command to the vehicle mobile terminal to activate the selected other semi-persistent radio resource configuration, or the receiver receives a request from the vehicle mobile terminal to activate other semi-persistent radio resource configuration, other than the semi-persistent radio resource configuration previously activated, the processor determines whether to activate the other semi-persistent radio resource configuration, and, in the affirmative, the transmitter transmits another activation command to the vehicle mobile terminal to activate the requested other semi-persistent radio resource configuration, other than the semi-persistent radio resource configuration previously activated; optionally, the other activation command is transmitted in a message via a physical downlink control channel (PDCCH).

[0381] According to the radio base station of the present disclosure, each of the plurality of semi-persistent radio resource configurations configured and transmitted identifies: radio resources and a period suitable for transmitting at least one of the supported data components, optionally, the plurality of semi-persistent radio resource configurations is transmitted in a message of a radio resource control (RRC) protocol, or the period for transmitting at least one of the data components, and the transmitter transmits information on radio resources that can be used by the vehicle mobile terminal to transmit at least one of the data components together with an activation command for activating one or more of the plurality of semi-persistent radio resource configurations, optionally, the activation command and the information on the radio resources are transmitted in a message via a physical downlink control channel (PDCCH).

[0382] According to the radio base station of the present disclosure, the plurality of semi-persistent radio resource configurations are configured such that there is one semi-persistent radio resource configuration for each data component having a certain message size and a certain transmission period, or the data components transmitted by the vehicle mobile terminal at the same time are transmitted as one message, and the plurality of semi-persistent radio resource configurations are configured such that there is one semi-persistent radio resource configuration for each possible message including one or more of the data components to be transmitted by the vehicle mobile terminal, such that the vehicle mobile terminal transmits a message including one or more data components based on the activated semi-persistent radio resource configuration corresponding to the included data components of the message to be transmitted.

[0383] Hardware and software implementation of the present disclosure

[0384] Other exemplary embodiments relate to the implementation of the above-described various embodiments using hardware, software, or software in cooperation with hardware. In this regard, a user terminal (mobile terminal) is provided. The user terminal is adapted to perform the methods described herein, including the corresponding entities of the methods, such as receivers, transmitters, processors, as appropriate.

[0385] It is also recognized that various embodiments can be implemented or carried out in whole or in part by a computing device (processor). The computing device or processor can be, for example, a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, etc. Various embodiments can also be performed or implemented with a combination of these devices. Specifically, each functional block used in the description of each of the above embodiments can be implemented as an integrated circuit by an LSI. They can be formed as chips individually, or one chip can be formed so as to include part or all of the functional blocks. They can include a data input and output coupled thereto. The LSI here can be referred to as an IC, a system LSI, a super LSI, or ultra LSI depending on a difference in the degree of integration. However, the technique of implementing integrated circuits is not limited to LSIs, and can be realized by using a dedicated circuit or a general-purpose processor. Further, a FPGA (Field Programmable Gate Array) that can be programmed after manufacturing LSIs, or a reconfigurable processor where connections and settings of circuit cells disposed inside the LSI can be reconfigured can be used.

[0386] In addition, various embodiments can also be implemented by software modules that are executed by a processor or by a hardware device. Also, software modules can be combined with hardware implementations. The software modules can be stored in any kind of computer readable storage media, such as RAM, EPROM, EEPROM, flash memory, register, hard disk, CD-ROM, DVD, etc. It should also be noted that each of the various features of the different embodiments can stand alone as a separate embodiment or be combined with any of the other embodiments.

[0387] Those skilled in the art will understand that numerous changes and / or modifications can be made to the present disclosure as shown in the specific embodiments. Therefore, the present embodiments are to be considered in all respects as illustrative and not restrictive.

Claims

1. A vehicular mobile device, comprising: a transmitter that transmits assistance information about D2D data transmissions having different possible transmission periodicities and / or different possible message sizes to a radio base station; a receiver that receives, from the radio base station, a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations configured to be usable for at least one of the D2D data transmissions, and receives, from the radio base station, an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for each of the D2D data transmissions for the vehicular mobile device; and the transmitter performs the one or more D2D data transmissions based on the radio resources and transmission periodicities configured by the activated one or more semi-persistent radio resource configurations.

2. The vehicular mobile device of claim 1, the transmitted assistance information about D2D data transmissions including at least one of: information about a portion or all of the different possible transmission periodicities and / or different possible message sizes for the one or more D2D data transmissions, and information about different D2D data transmissions to assist the radio base station in determining different possible transmission periodicities and / or different possible message sizes based on the received assistance information about different possible D2D data transmissions.

3. The vehicular mobile device of claim 1, the transmitter further transmits information about vehicular parameters supported by the vehicular mobile device to the radio base station, the information about vehicular parameters usable by the radio base station to determine different possible transmission periodicities for the one or more D2D data transmissions, and the transmitter further transmits information about vehicular parameters currently experienced by the vehicular mobile device to the radio base station, the information about current vehicular parameters usable by the radio base station to select one or more of the plurality of semi-persistent radio resource configurations to activate.

4. The vehicle movement apparatus according to claim 3, wherein the vehicular parameters include speed.

5. The vehicular mobile device of claim 3 or 4, the transmitter further transmits information about a changed vehicular parameter to the radio base station when one of the vehicular parameters changes by more than a predetermined threshold, and the receiver in turn receives, from the radio base station, a further activation command to activate other semi-persistent radio resource configurations other than the previously activated semi-persistent radio resource configurations, or the transmitter further requests, from the radio base station, activation of other semi-persistent radio resource configurations in addition to the previously activated semi-persistent radio resource configurations when one of the vehicular parameters changes by more than a predetermined threshold, and the receiver in turn receives, from the radio base station, a further activation command to activate the other requested semi-persistent radio resource configurations other than the previously activated semi-persistent radio resource configurations, and the transmitter further transmits the one or more D2D data transmissions based on the radio resources and transmission periodicities configured by the activated other semi-persistent radio resource configurations, wherein the further activation command is received in a message via a physical downlink control channel, PDCCH.

6. The vehicle moving apparatus of claim 1, the assistance information on the D2D data transmission being transmitted within one message, or the assistance information on the D2D data transmission being transmitted within at least two separate messages, wherein information on different possible periodicities of the one or more D2D data transmissions is transmitted within a first message, and information on a message size of at least one D2D data transmission to be transmitted by the vehicle moving apparatus is transmitted by the vehicle moving apparatus together with a buffer status report indicating that data of the one D2D data transmission is waiting for transmission.

7. The vehicle moving apparatus of claim 1, each of the received plurality of semi-persistent radio resource configurations identifying: a radio resource and a periodicity suitable for transmitting at least one of the D2D data transmissions, wherein the plurality of semi-persistent radio resource configurations is received in a message of a radio resource control, RRC, protocol, or a periodicity for transmitting at least one of the D2D data transmissions, and information on a radio resource that can be used by the vehicle moving apparatus for transmitting at least one of the D2D data transmissions is received together with an activation command for activating one or more of the plurality of semi-persistent radio resource configurations, wherein the activation command and the information on the radio resource are received in a message via a physical downlink control channel, PDCCH.

8. The vehicle moving apparatus of claim 1, data of D2D data transmissions to be transmitted at the same time being transmitted as one message or as separate messages.

9. The vehicle moving apparatus of claim 1, the receiving entity comprising other vehicles or non-vehicle moving apparatuses, and data of the D2D data transmissions being transmitted via a sidelink connection, and / or the receiving entity comprising the radio base station, and the data of the D2D data transmissions being transmitted via a radio connection.

10. The vehicle moving apparatus of claim 1, the plurality of semi-persistent radio resource configurations being configured such that there is one semi-persistent radio resource configuration for each D2D data transmission having a certain message size and a certain transmission periodicity, or data of D2D data transmissions transmitted at the same time being transmitted as one message, and the plurality of semi-persistent radio resource configurations being configured such that there is one semi-persistent radio resource configuration for each possible message comprising one or more D2D data transmissions to be transmitted by the vehicle moving apparatus, wherein the transmitter transmits a message comprising data of one or more D2D data transmissions based on the activated semi-persistent radio resource configuration corresponding to the data of the D2D data transmissions comprised by the message to be transmitted.

11. A radio base station, comprising: a receiver that receives, from a vehicle moving apparatus, assistance information on D2D data transmissions having different possible transmission periodicities and / or different possible message sizes; a transmitter that transmits, to the vehicle moving apparatus, an activation command for activating one or more of the plurality of semi-persistent radio resource configurations, wherein the activation command is transmitted in a message via a physical downlink control channel, PDCCH. circuitry configured to configure a plurality of semi-persistent radio resource configurations based on a transmission period of the different possible transmission periods, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; a transmitter configured to transmit information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; the circuitry is configured to select one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device for periodically allocating radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and the transmitter is configured to transmit an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

12. The radio base station of claim 11, the received assistance information about the D2D data transmissions comprising at least one of: information about a part or all of different possible transmission periods and / or different possible message sizes of the one or more D2D data transmissions, and information about different D2D data transmissions, the circuitry being further configured to determine different possible transmission periods and / or different possible message sizes based on the received assistance information about different possible D2D data transmissions.

13. The radio base station of claim 11, the receiver being further configured to receive information about vehicle parameters supported by the vehicle mobile device from the vehicle mobile device, the circuitry being further configured to determine different possible transmission periods of the one or more D2D data transmissions based on the received information about vehicle parameters, and the receiver being further configured to receive information about vehicle parameters currently experienced by the vehicle mobile device from the vehicle mobile device, the circuitry being further configured to select the one or more of the plurality of semi-persistent radio resource configurations to be activated based on the received current vehicle parameters.

14. The radio base station according to claim 13, wherein the vehicle parameters comprise a speed.

15. The radio base station of claim 13 or 14, the receiver being configured to receive information about changed vehicle parameters from the vehicle mobile device, and the circuitry being configured to select other semi-persistent radio resource configurations, other than previously selected and activated semi-persistent radio resource configurations, based on the changed vehicle parameters, and the transmitter being configured to transmit another activation command to the vehicle mobile device to activate the selected other semi-persistent radio resource configurations, or the receiver being configured to receive a request from the vehicle mobile device for activating other semi-persistent radio resource configurations in addition to the previously activated semi-persistent radio resource configurations, the circuitry being configured to determine whether to activate the other semi-persistent radio resource configurations, and, in the affirmative, the transmitter being configured to transmit another activation command to the vehicle mobile device for activating the requested other semi-persistent radio resource configurations, other than the previously activated semi-persistent radio resource configurations; wherein the another activation command being transmitted in a message via a physical downlink control channel, PDCCH.

16. The radio base station of claim 11, each of the plurality of configured and transmitted semi-persistent radio resource configurations identifying: a radio resource and a periodicity suitable for transmitting at least one of the D2D data transmissions, wherein the plurality of semi-persistent radio resource configurations is transmitted in a message of the radio resource control, RRC, protocol, or a periodicity for transmitting at least one of the data components and information about a radio resource that can be used by the vehicle mobile device for transmitting at least one of the data of the D2D data transmissions is transmitted by the transmitter together with an activation command for activating one or more of the plurality of semi-persistent radio resource configurations, wherein the activation command and the information about the radio resource are transmitted in a message via a physical downlink control channel, PDCCH.

17. The radio base station of claim 11, the plurality of semi-persistent radio resource configurations being configured such that there is one semi-persistent radio resource configuration for each data component having a certain message size and a certain transmission periodicity, or the data of the D2D data transmissions transmitted by the vehicle mobile device at the same time are transmitted as one message and the plurality of semi-persistent radio resource configurations are configured such that there is one semi-persistent radio resource configuration for each possible message comprising one or more of the data of the D2D data transmissions to be transmitted by the vehicle mobile device, such that the vehicle mobile device transmits a message comprising one or more data of the D2D data transmissions based on the activated semi-persistent radio resource configuration corresponding to the data of the D2D data transmissions comprised by the message to be transmitted.

18. A method for a vehicle mobile device, the method comprising: transmitting assistance information about D2D data transmissions having different possible transmission periodicities and / or different possible message sizes to a radio base station; receiving from the radio base station a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations being configured to be usable for at least one of the D2D data transmissions, and receiving from the radio base station an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically assign radio resources for each of the D2D data transmissions for the vehicle mobile device; and performing the one or more D2D data transmissions based on the radio resources and transmission periodicities configured by the activated one or more semi-persistent radio resource configurations.

19. A method for a radio base station, the method comprising: receiving from a vehicle mobile device assistance information about D2D data transmissions having different possible transmission periodicities and / or different possible message sizes; configuring a plurality of semi-persistent radio resource configurations based on a transmission periodicity of the different possible transmission periodicities of the one or more D2D data transmissions, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; sending information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and sending an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

20. An integrated circuit for controlling a process of a vehicle mobile device, the process comprising: sending assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes to a radio base station; receiving from the radio base station a plurality of semi-persistent radio resource configurations configured by the radio base station, each of the plurality of semi-persistent radio resource configurations being configured to be usable for at least one of the D2D data transmissions, and receiving from the radio base station an activation command to activate one or more of the plurality of semi-persistent radio resource configurations to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and performing the one or more D2D data transmissions based on radio resources and transmission periods configured by the activated one or more semi-persistent radio resource configurations.

21. An integrated circuit for controlling a process of a radio base station, the process comprising: receiving from a vehicle mobile device assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes; configuring a plurality of semi-persistent radio resource configurations based on transmission periods of the different possible transmission periods of the one or more D2D data transmissions, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; sending information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and sending an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

21. An integrated circuit for controlling a process of a radio base station, the process comprising: receiving from a vehicle mobile device assistance information about D2D data transmissions having different possible transmission periods and / or different possible message sizes; configuring a plurality of semi-persistent radio resource configurations based on transmission periods of the different possible transmission periods of the one or more D2D data transmissions, each of the plurality of semi-persistent radio resource configurations being configured to be usable for transmitting at least one of the D2D data transmissions; sending information about the configured plurality of semi-persistent radio resource configurations to the vehicle mobile device; selecting one or more of the plurality of semi-persistent radio resource configurations to be activated for the vehicle mobile device to periodically allocate radio resources for the vehicle mobile device to transmit each of the D2D data transmissions; and sending an activation command to the vehicle mobile device to activate the selected one or more semi-persistent radio resource configurations for the vehicle mobile device.

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