Method of operating a network infrastructure side network element, network infrastructure side network element, method of operating a road side network element, road side network element

Abstract

A method for operating a network infrastructure-side network unit of a cell-based wireless communication network is presented. The method comprises determining (204) a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road-side network unit; sending (206) the first scheduling grant message to the road-side network unit on a downlink channel; receiving (208) from the road-side network unit on the uplink channel an indication that the assigned sidelink resource of the first sidelink channel is occupied; determining (210) a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel within a licensed frequency range to the road-side network unit; and sending (212) the second scheduling grant message to the road-side network unit on the downlink channel.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for operating a network infrastructure side network element, a network infrastructure side network element, a method for operating a road side network element and a road side network element. BACKGROUND

[0002] It is known that today's vehicles are already able to exchange information with other vehicles in their vicinity (V2V: Vehicle to Vehicle). Vehicles can also communicate wirelessly with road side infrastructure (V2I: Vehicle to Infrastructure). Likewise, vehicles can communicate wirelessly with background servers in the Internet (V2N: Vehicle to Network) or with pedestrian terminal devices (V2P: Vehicle to Person). This communication is also referred to as Vehicle-to-Everything (V2X) as a whole.

[0003] The development of new functions and services in the automotive industry, such as autonomous driving, benefits from V2X. Traffic safety, driving comfort and energy efficiency can be improved. This leads to new products and business models for car manufacturers, automotive suppliers and other service providers.

[0004] The first generation of V2X applications to be used in the coming years mainly involves applications on the road. The aim is to provide drivers with information about the environment around the road. Vehicles periodically provide status information (e.g. position, speed, acceleration, etc.) and / or event information (rescue action, stranded vehicle, traffic jam). This information is usually sent locally in the form of short messages. Neighboring vehicles can forward this event-based information to a central network element (base station, background).

[0005] For V2X direct Device-to-Device (D2D) communication, currently two competing technologies exist. The first technology is based on the radio technology IEEE 802.11p, which forms the basis of the overall standard DSRC (Dedicated Short Range Communication) in the USA and of the overall standard ETSI ITS G5 (ETSI: European Telecommunications Standards Institute; ITS: Intelligent Transport Systems) in Europe. The second technology is based on 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) and is also known under the abbreviation LTE-V2X. Further developments of the LTE-V2X technology are expected in the case of 5G (5th generation mobile networks).

[0006] The IEEE 802.11p standard uses a PHY layer based on the IEEE 802.11a standard with some modifications. The MAC layer is based on Enhanced Distributed Channel Access (EDCA) which is based on contention. Also, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) is used. CSMA / CA follows the Listen-Before-Talk principle in order to reduce collisions on the channel to a minimum. If a network unit (in this context a vehicle) has data to transmit, it performs a channel measurement in order to check whether the channel is occupied. If the channel is recognized as free, the network unit with the planned transmission waits for a randomly determined time and then starts the transmission. If the channel is occupied during the channel measurement, the network unit will perform a Backoff procedure, that is, it waits for a randomly determined period of time for the next channel access. The more network units trying to send within a geographical area, the higher the probability that a network unit delays its transmission, which leads to an overall increase in latency in the network. The IEEE 802.11p standard provides advantages with respect to latency and signaling overhead and is adapted to the application case V2V compared to other WLAN standards based on IEEE 802.11.

[0007] The LTE extension for V2X starting from 3GPP Release 14 proposes to use licensed and / or unlicensed spectrum for communication. V2V communication is based on a direct Device-to-Device interface (also called Sidelink interface on the physical layer). Unlike 802.11p, the transmission is realized in a cell-protected manner, that is, planned by the network. The transmission rights are issued by a scheduling unit in the base station so that collisions are avoided and interference is reduced to a minimum. The control by the base station can only be performed in areas where the base station signal is available (in-coverage). In the case where no base station signal is provided (out-of-coverage), communication is performed by the sidelink with predefined parameters.

[0008] In the development of communication standards, different standards can be proposed for the same frequency range, e.g. based on different applications or development activities from different technical fields. By this, different wireless communication systems can transmit in the same frequency range and a performance degradation can result for both technologies.

[0009] Therefore, it can be an objective technical task to create a coexistence mechanism for two different wireless communication technologies in order to fairly divide the existing resources. SUMMARY

[0010] The problem underlying the present application is solved by a method for operating a network infrastructure side network unit according to claim 1 and according to the dependent claims, a network infrastructure side network unit according to the dependent claims, a method for operating a road side network unit according to the dependent claims and a road side network unit according to the dependent claims.

[0011] According to the first and second aspect, a method for operating a network infrastructure side network unit and a network infrastructure side network unit are presented. A scheduling request message for a first sidelink channel in an unlicensed frequency range is received from a road side network unit on an uplink channel. A first scheduling grant message is determined, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit. The first scheduling grant message is transmitted to the road side network unit on a downlink channel. An indication that the assigned sidelink resource of the first sidelink channel is occupied is received from the road side network unit on the uplink channel. A second scheduling grant message is determined, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the road side network unit. The second scheduling grant message is transmitted to the road side network unit on the downlink channel.

[0012] According to the third and fourth aspect, a method for operating a road side network unit and a road side network unit are presented. A message is determined for transmitting to other road side network units. A scheduling request message for a first sidelink channel in an unlicensed frequency range is transmitted to a network infrastructure side network unit on an uplink channel. A first scheduling grant message is received from the network infrastructure side network unit on a downlink channel, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit. It is determined that the assigned sidelink resource of the first sidelink channel is occupied. An indication that the assigned sidelink resource of the first sidelink channel is occupied is transmitted to the network infrastructure side network unit on the uplink channel. A second scheduling grant message is received from the network infrastructure side network unit on the downlink channel, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel to the road side network unit. The message is transmitted to the other road side network units on the second sidelink channel.

[0013] Advantageously, according to the third to fourth aspect, since the second sidelink channel is used as a backup channel for the first sidelink channel, the reliability of the transmission of the message via the sidelink channel is ensured. At the same time, the second sidelink channel is only used as a backup channel when the first sidelink channel is occupied. Thereby it is guaranteed that first a data transmission is tried to be loaded to the first sidelink channel before the second sidelink channel in the licensed frequency range is used. Thus, advantageously, the advantageous first sidelink channel is preferably used, but at the same time, if a collision should occur on the first sidelink channel, the allocation of the message is guaranteed by the second sidelink channel.

[0014] According to the fifth and sixth aspect, a method for operating a network infrastructure side network unit and a network infrastructure side network unit are proposed. A first group of road side network units within a cell of the network infrastructure side network unit is determined. A second group of road side network units within the cell of the network infrastructure side network unit is determined, wherein the first and the second group are disjoint. A first scheduling request message is received on an uplink channel from a first road side network unit of the first group. A first scheduling grant message is determined, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of a first sidelink channel within an unlicensed frequency range to the first road side network unit of the first group. The first scheduling grant message is transmitted on a downlink channel to the first road side network unit. A second scheduling request message is received on the uplink channel from a second road side network unit of the second group. A second scheduling grant message is determined, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel within a licensed frequency range to the second road side network unit of the second group. The second scheduling grant message is transmitted on the downlink channel to the second road side network unit.

[0015] Advantageously, according to the fifth and sixth aspect, the reliability of the transmission of messages via the sidelink channels is improved, because the distribution of the road side network units into two groups comprises distributing the transmission onto the first and the second sidelink channel. By grouping into the second group, the road side network units are taken away from the first sidelink channel and resources are freed for other network units, i.e. for example ITS-G5 network units, which are not controlled by the network infrastructure side network unit.

[0016] A common aspect of all aspects is that the transmission between the network units controlled by the network infrastructure side network unit is distributed over two sidelink channels. BRIEF DESCRIPTION OF DRAWINGS

[0017] Further features and advantages will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. In the drawings:

[0018] Figure 1 A first cell based wireless communication network and a second wireless communication network are shown;

[0019] Figure 2 、 3 , 5, 8 and 9 show schematic flow diagrams, respectively;

[0020] Figure 4 and 6 show schematic sequence diagrams, respectively; and

[0021] Figure 7 shows a schematic block diagram for determining a probability of collision. DETAILED DESCRIPTION

[0022] Figure 1 A first cell-based wireless communication network CELL and a second wireless communication network VANET are shown. The first wireless communication network CELL comprises a network infrastructure side network unit BS, a first road side network unit UE1 and a second road side network unit UE2. The network infrastructure side network unit BS comprises a processor P BS, a storage element M BS and a transceiver T BS. The network infrastructure side network unit BS can also be referred to as a base station or eNodeB. The network infrastructure side network unit BS is connected with a fixed antenna A BS in order to transmit data on a Downlink channel DC and to receive data on an Uplink channel UC. The antenna A BS comprises for example a plurality of antennas and is for example implemented as a Remote Radio Head, i.e. RRH. The network infrastructure side network unit BS and the antenna A BS provide a cell C within which the road side network units UE1 and UE2 communicate with the network unit BS. Of course, the network infrastructure side network unit BS can also be constructed distributed within a virtualization framework and consist of decentralized network units. The network units BS, UE1 and UE2 are configured for example according to the LTE-V2X standard.

[0023] The road side network units UE1 and UE2 comprise each a processor P1, P2, a storage element M1, M2, a transceiver T1, T2 and an antenna A1, A2. The two road side network units UE1, UE2 are within the cell C, receive data on the Downlink channel DC and transmit data on the Uplink channel UC. The two road side network units UE1, UE2 can directly communicate with each other over a first sidelink channel SC1 within an unlicensed frequency range NLFB and over a second sidelink channel SC2 within a licensed frequency range LFB.

[0024] The two road side network units UE1, UE2 are within the cell C and are able to receive data on the Downlink channel DC and to transmit data on the Uplink channel UC. The two road side network units UE1, UE2 are able to directly communicate with each other over a sidelink channel SC1 within an unlicensed frequency range NLFB and over a sidelink channel SC2 within a licensed frequency range LFB.

[0025] A national authority such as the Federal Network Agency of the Federal Republic of Germany establishes a frequency usage plan, which for example includes licenses for the respective network operators. Within the framework of the assigned licenses, the network operators are allowed to use the network infrastructure and the terminal devices within the assigned, that is, licensed frequency range or spectrum. In contrast, there are frequency ranges or spectra which are not assigned to a network operator and which can be used freely under certain boundary conditions such as reduced transmission / reception power.

[0026] In this specification, reference is made to a unique uplink channel and a unique downlink channel. For example, the uplink channel and the downlink channel comprise respective sub-channels, that is, multiple channels can be used in the uplink as well as in the downlink. The same applies to the sidelink channels SC1, SC2.

[0027] The second wireless communication network VANET comprises two further road-side network elements NE3 and NE4, which each comprise a processor P3, P4, a storage element M3, M4, a transceiver T3, T4, and an antenna A3, A4. The network elements NE3 and NE4 are configured, for example, according to the IEEE 802.1 1 p standard. The network elements NE3 and NE4 directly communicate with each other within the unlicensed frequency range NLFB via an ad-hoc channel ADCH. The ad-hoc channel ADCH is arbitrated by the transceivers T3, T4 via the CSMA / CA protocol (CSMA / CA: Carrier Sense Multiple Access / Collision Avoidance).

[0028] On the storage elements M1, M2, M3, M4, respective computer programs are stored, which, when implemented on the respective processors P1, P2, P3, P4, implement the methods disclosed in this specification. Alternatively, the processors P1, P2, P3, P4 are implemented as ASICs.

[0029] The third and fourth network elements NE3 and NE4 are in the vicinity of the two first and second network elements UE1 and UE2, in particular within the area of the cell C, such that the respective transmission power is sufficient to interfere with the transmission of the network elements UE1 and UE2 within the unlicensed frequency range NLFB. Thus, the transmission on the channels ADCH and SC1 can have a detrimental effect on each other. It is an object of this specification to reduce this detrimental effect on each other.

[0030] The sidelink channels SC1 and SC2 are operated in a so-called managed mode, which means that the network elements BS control the transmission on the sidelink channels SC1 and SC2 by corresponding messages in the downlink channel DC. The ad-hoc channel ADCH is not operated in managed mode. Therefore, the road-side network elements NE3, NE4 have independent access to the ad-hoc channel ADCH.

[0031] The road-side network elements UE1, UE2, NE3 and NE4 are arranged in the respective motor vehicles vehic1, vehic2, vehic3, vehic4 and are connected with not shown control devices arranged there for data exchange. Alternatively, the road-side network elements UE1, UE2, NE3 and NE4 are part of the control devices in the respective motor vehicles vehic1, vehic2, vehic3, vehic4. In another alternative embodiment, the road-side network elements UE1, UE2, NE3 and NE4 are arranged in static infrastructure such as traffic lights instead of in motor vehicles.

[0032] The sidelink channels SC1, SC2 and generally the sidelink are defined by the document 3GPP TS 36.300 V14.2.0 (2017-03), which is incorporated by reference into the present specification. The sidelink comprises Sidelink Discovery, Sidelink Communication and V2X Sidelink Communication between the network elements UE1, UE2. The sidelink uses uplink resources and a physical channel structure similar to the uplink. Therefore, the sidelink differs from the uplink with respect to the physical channel.

[0033] The sidelink is limited to groupcast transmission for physical sidelink channels. The sidelink also uses a 1-symbol gap at the end of each Sidelink-Subframe. For V2X Sidelink Communication, the PSCCH, Physical Sidelink Control Channel, and the PSSCH, Physical Sidelink Shared Channel, are transmitted in the same subframe. The sidelink channels SC1, SC2 are for example the PSSCH.

[0034] The physical layer processing of the transmission channel in the sidelink differs from the uplink transmission in the following steps: scrambling: for PSDCH, i.e. Physical Sidelink Discovery Channel, and PSCCH, the scrambling is not specific to the network element; modulation: 64 QAM and 256 QAM are not supported for the sidelink (QAM: Quadrature amplitude modulation). The PSCCH specifies the sidelink resources and other transmission parameters for the PSSCH by the respective network element UE1, UE2.

[0035] For the PSDCH, PSCCH and PSSCH demodulation, the reference signal is transmitted similarly to the uplink demodulation reference signal in the 4th symbol of the slot in the standard CP, i.e. Cyclic Prefix, and in the 3rd symbol of the slot in the extended CP. The sidelink demodulation reference signal sequence length corresponds to the size of the allocated resource (number of subcarriers). For V2X sidelink communication, the reference signal is transmitted in the 3rd and 6th symbol of the first slot in the CP and in the 2nd and 5th symbol of the second slot in the CP. For PSDCH and PSCCH, the reference signal is generated based on a fixed base sequence, a cyclic shift and an orthogonal cover code. For V2X sidelink communication, the cyclic shift for PSCCH is randomly selected at each transmission.

[0036] For the measurement of the respective sidelink channel SC1, SC2, the following possibilities are provided on the side of the network element UE1, UE2: received power of the sidelink reference signal (S-RSRP); received power of the sidelink discovery reference signal (SD-RSRP); received power of the PSSCH reference signal (PSSCH-RSRP); signal strength indicator for the sidelink reference signal (S-RSSI).

[0037] The Ad-Hoc channel ADCH and the Ad-Hoc wireless communication network VANET are defined, for example, by the IEEE standard "802.11p-2010 - IEEE Standard for Information technology - Local and metropolitan area networks - Specific requirements - Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 6: Wireless Access in Vehicular Environments", which is incorporated by reference into the present specification. IEEE 802.11p is a standard for extending the WLAN standard IEEE 802.11. The goal of IEEE 802.11p is to set up WLAN technology in the person- motor vehicle and to provide a reliable interface for the application of Intelligent Transport Systems (ITS). IEEE 802.11p is also the basis for Dedicated Short Range Communication (DSRC) in the frequency band from 5.85 to 5.925 GHz. In order to avoid confusion with the European version of DSRC, the term ITS-G5 is used in Europe, in particular, instead of DSRC.

[0038] The two lowest layers of the ITS-G5 technology (ITS-G5: Intelligent Transport Systems operating in the 5 GHz frequency band), i.e. the physical layer and the data link layer, are described by referring to the document "ETSI TS 302 663 V1.2.0 (2012-11)" which is incorporated into the present specification. The transceivers TA1 and TA3 implement these two lowest layers and the corresponding functionalities according to "ETSI TS 102 687 V1.1.1 (2011-07)" in order to use the ad-hoc channel ADCH. In order to use the ad-hoc channel ADCH, the following unlicensed frequency ranges are provided in Europe which are part of the unlicensed frequency range NLFB: 1) ITS-G5A for safety-related applications in the frequency range from 5.875 GHz to 5.905 GHz; 2) ITS-G5B for non-safety-related applications in the frequency range from 5.855 GHz to 5.875 GHz; and 3) ITS-G5D for ITS applications operating in the frequency range from 5.905 GHz to 5.925 GHz. ITS-G5 enables a communication between the two network elements UE1 and UE2 outside the environment of a base station. ITS-G5 enables an immediate exchange of data frames and avoids the management overhead used when setting up a network.

[0039] Decentralized Congestion Control Mechanisms" are described with reference to the document "ETSI TS 102 687 V1.1.1 (2011-07)" which is incorporated into the present specification for ITS-G5. The Ad-Hoc Channel ADCH is used, inter alia, for the exchange of data relating to traffic safety and traffic efficiency. The transceivers TA1 and TA3 implement, for example, the functionality as described in the document "ETSI TS 102 687 V1.1.1 (2011-07)". Applications and services in ITS-G5 are based on the cooperative behavior of road-side network elements which form an Ad-Hoc network VANET (VANET: vehicular ad hoc network). The Ad-Hoc network VANET enables time-critical road traffic applications in which a fast exchange of information is required in order to timely alert and assist drivers and / or vehicles. In order to ensure the proper functioning of the Ad-Hoc network VANET, the Ad-Hoc Channel ADCH for ITS-G5 uses "Decentralized Congestion Control Mechanisms (DCC)". The DCC has functions which are located at various layers of the ITS architecture. The DCC mechanism is based on knowledge about the channel. Channel state information is obtained by channel sounding. Channel state information can be obtained by TPC (transmit power control), TRC (transmit rate control) and TDC (transmit data rate control) methods. These methods determine channel state information from a received signal level threshold or preamble information of a detected packet.

[0040] Figure 2A schematic flow chart for operating a network infrastructure side network unit BS is shown. In step 202, a scheduling request message for a first sidelink channel in an unlicensed frequency range is received from a road side network unit on an uplink channel. In step 204, a first scheduling grant message is determined, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit. In step 206, the first scheduling grant message is transmitted to the road side network unit on a downlink channel. In step 208, an indication that the assigned sidelink resource of the first sidelink channel is occupied is received from the road side network unit on the uplink channel. In step 210, a second scheduling grant message is determined, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the road side network unit. In step 212, the second scheduling grant message is transmitted to the road side network unit on the downlink channel.

[0041] Figure 3 A schematic flow chart for operating a road side network unit UE1 or UE2 is shown. In step 302, a message for transmitting to other road side network units is determined. In step 304, a scheduling request message for a first sidelink channel in an unlicensed frequency range is transmitted to a network infrastructure side network unit on an uplink channel. In step 306, a first scheduling grant message is received from the network infrastructure side network unit on a downlink channel, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit. In step 308, it is determined that the assigned sidelink resource of the first sidelink channel is occupied. In step 310, an indication that the assigned sidelink resource of the first sidelink channel is occupied is transmitted to the network infrastructure side network unit on the uplink channel. In step 312, a second scheduling grant message is received from the network infrastructure side network unit on the downlink channel, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel to the road side network unit. In step 314, the message is transmitted to the other road side network units on the second sidelink channel.

[0042] Figure 4An exemplary sequence diagram is shown. In step 302, a message P in the form of effective data is determined by the road-side network unit UE1 in order to transmit the message in a scheduled resource. A scheduling request message BSR, for example a Buffer Status Report, is transmitted via an uplink channel UC to the network infrastructure side network unit BS. In step 204, the network infrastructure side network unit BS determines a scheduling grant message G1 which is transmitted on a downlink channel DC to the first network unit UE1. After obtaining the scheduling grant message G1, the network unit UE1 tries to transmit the message P in step 308 according to a listen-before-talk method (LBT). If the network unit UE1 determines that the first sidelink channel is free, the network unit transmits the message P through the allocated resource of the first sidelink channel. For this purpose, the network unit UE1 interrogates the first sidelink channel in order to determine whether the first sidelink channel is occupied.

[0043] In this specification, a resource is to be understood as a time, a frequency and / or a modulation and coding scheme information which is used for transmission on one of these channels and which is scheduled in advance by the network infrastructure side network unit.

[0044] If at the point in time of the channel listening of the network unit UE1 a communication between the network units NE3 and NE4 via the ad-hoc channel ADCH in the same frequency range takes place, the network unit UE1 considers by means of the channel measurement that the first sidelink channel on the same frequency range is occupied. An indication I, for example existing as bit information, indicates that the first road-side network unit UE1 cannot use the resource allocated to it. In step 310, the indication I is transmitted via the uplink channel UC to the network infrastructure side network unit BS. In step 210, the network infrastructure side network unit BS determines a second scheduling grant message G2 from the indication I and transmits the second scheduling grant message via the downlink channel DC to the first road-side network unit UE1. In step 314, the first road-side network unit UE1 transmits the message P through the allocated resource of the second sidelink channel SC2 with increased reliability because the second sidelink channel SC2 is within the licensed frequency range LSB and thus no interference of other unscheduled network units is to be expected. Thus, the second sidelink channel SC2 is used as a backup channel for the first sidelink channel.

[0045] Figure 5 An exemplary sequence diagram is shown. In step 302, a message P in the form of effective data is determined by the road-side network unit UE1 in order to transmit the message in a scheduled resource. A scheduling request message BSR, for example a Buffer Status Report, is transmitted via an uplink channel UC to the network infrastructure side network unit BS. In step 204, the network infrastructure side network unit BS determines a scheduling grant message G1 which is transmitted on a downlink channel DC to the first network unit UE1. After obtaining the scheduling grant message G1, the network unit UE1 tries to transmit the message P in step 308 according to a listen-before-talk method (LBT). If the network unit UE1 determines that the first sidelink channel is free, the network unit transmits the message P through the allocated resource of the first sidelink channel. For this purpose, the network unit UE1 interrogates the first sidelink channel in order to determine whether the first sidelink channel is occupied. Figure 1a schematic flow chart of a network infrastructure side network unit BS. In step 502, a first set of road side network units within a cell of the network infrastructure side network unit is determined. In step 504, a second set of road side network units within the cell of the network infrastructure side network unit is determined, wherein the first and second sets are disjoint. In step 506, a first scheduling request message is received on an uplink channel from a first road side network unit of the first set. In step 508, a first scheduling grant message is determined, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of a first sidelink channel in an unlicensed frequency range to the first road side network unit of the first set. In step 510, the first scheduling grant message is transmitted on a downlink channel to the first road side network unit. In step 512, a second scheduling request message is received on an uplink channel from a second road side network unit of the second set. In step 514, a second scheduling grant message is determined, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the second road side network unit of the second set. In step 516, the second scheduling grant message is transmitted on a downlink channel to the second road side network unit.

[0046] Figure 6 A schematic sequence diagram is shown. In step 502, the network unit BS divides the road side network units UE1 and UE2 into respective groups Gr1, Gr2. Of course, the groups Gr1 and Gr2 comprise further road side network units as well. In step 602, the road side network unit UE1 determines that valid data P1 is available for transmission to the second road side network unit UE2 and, for this purpose, transmits a first scheduling request message BSR1 on an uplink channel UC to the network infrastructure side network unit BS in step 604. In step 508, the network unit BS determines a first scheduling grant message G3 in order to transmit the scheduling grant message on a downlink channel DC in step 510. In step 606, the first network unit UE1 checks whether the first sidelink channel SC1 is free. In the present case, this is the case and, in step 608, the first network unit UE1 transmits the valid data P1 on the first sidelink channel SC1 in the unlicensed frequency range to the second road side network unit UE2.

[0047] In step 610, the second road-side network unit UE2 determines the payload P2 in order to transmit these payload data to the first road-side network unit UE1. For this purpose, in step 612, the second road-side network unit transmits a scheduling request message BSR2 to the network infrastructure side network unit BS via the uplink channel UC. In step 514, the network unit BS determines a second scheduling grant message G4 for the second sidelink channel SC2 from the second scheduling request message BSR2 and transmits this second scheduling grant message to the second road-side network unit UE2 in step 516. After obtaining the second scheduling grant message G4, the second road-side network unit UE2 does not perform a listen-before-talk method but transmits the payload data P2 to the first road-side network unit UE1 on the resources allocated by the second scheduling grant message G4 on the second sidelink channel SC2 in step 614. The simultaneous wireless communication between the road-side network units NE3 and NE4 on the ad-hoc channel ADCH does not interfere with the communication according to step 614, because the frequency range of the ad-hoc channel ADCH and the second sidelink channel SC2 is different.

[0048] Not only the first road-side network unit UE1 but also the second road-side network unit UE2 receives the scheduling grant messages G3 and G4 and is accordingly ready to receive on not only the first sidelink channel SC1 but also on the second sidelink channel SC2.

[0049] Figure 7 A schematic block diagram for determining the collision probability C on the first sidelink channel SC1 in Figure 1 is shown. The first occupancy information Ol is determined by a channel measurement of the first sidelink channel by the network infrastructure side network unit BS. The first occupancy information Ol contains information that a possible data transmission is taking place on the first sidelink channel, which data transmission can not only come from the cell-based wireless communication network CELL but also from the second wireless communication network VANET. Furthermore, the second occupancy information O2 is known by the scheduler of the network infrastructure side network unit BS, which second occupancy information contains the resources that are scheduled, i.e. occupied, on the first sidelink channel. The second occupancy information O2 exists for example as bit information, wherein a zero represents a free state of the first sidelink channel and a one represents an occupied state of the first sidelink channel. The third occupancy information O3 is obtained with the exclusive OR operation Ol XOR O2. The third occupancy information O3 corresponds to the occupation of the first sidelink channel by the road-side network units NE3, NE4, which are not operated in the cell-based wireless communication network, i.e. for example according to the transmission of ETSI ITS-G5.

[0050] Thus, the collision probability C can be determined from the third occupancy information O3. For example, the portion A(O3) is selected from the occupancy information O3 and the collision probability C is determined according to block 702, exemplarily in case of 5 occupied out of 20 time slots, the collision probability is 25%.

[0051] Figure 8 An exemplary flow chart for operating a network infrastructure side network unit BS is shown. In step 802, the collision probability on the first sidelink channel in the unlicensed frequency range is determined, for example, according to Figure 7 In step 804, sidelink resources on the second sidelink channel are reserved according to the determined collision probability. If, for example, the collision probability is determined to be 20% and there are 10 road side network units of the cell based wireless network in the cell, then, for example, two resources are reserved on the second sidelink channel. In step 210, at least a portion of the reserved sidelink resources are scheduled, that is, sidelink resources of the second sidelink channel are assigned to road side network units which cannot transmit their data in the first sidelink channel.

[0052] The determined reserved and / or scheduled resources in the first and second sidelink channels are allocated by the network infrastructure side network unit BS to the first and second network units UE1 and UE2, for example, by means of a broadcast, in particular by means of a radio resource control message. This can additionally take place during a cell-attachment procedure, a handover procedure of the road side network units UE1, UE2.

[0053] Figure 9 An exemplary flow chart for operating a network infrastructure side network unit BS is shown. In step 902, the collision probability on the first sidelink channel in the unlicensed frequency range is determined, for example, according to Figure 7to determine a probability of collision on the first sidelink channel. In step 904, a first group of road side network units within the cell is determined depending on the determined probability of collision. In step 906, a second group of road side network units within the cell is determined depending on the determined probability of collision. This way, the groups are adapted to the occupancy of the first sidelink channel. For example, at a first point in time, the probability of collision is 0% and a number of ten road side network units are assigned to the first group for transmitting on the first sidelink channel in the unlicensed frequency range. If now at a second point in time the probability of collision rises to 20%, a number of two road side network units are assigned to the second group for transmitting on the second sidelink channel in the licensed frequency range. A number of eight network units are assigned to the first group. If the probability of collision re- descends subsequently, the road side network units are transferred from the second group to the first group. Thus, it is ensured that the first sidelink channel is utilized as completely as possible in the unlicensed frequency range.

[0054] Further aspects of the present specification are set out in the subsequent clauses:

[0055] (Clause 1) A method for operating a network infrastructure side network unit of a cell-based wireless communication network, the method comprising: receiving a scheduling request message from a road side network unit on an uplink channel for a first sidelink channel in an unlicensed frequency range; determining a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit; transmitting the first scheduling grant message to the road side network unit on a downlink channel; receiving an indication from the road side network unit on the uplink channel that the assigned sidelink resource of the first sidelink channel is occupied; determining a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the road side network unit; and transmitting the second scheduling grant message to the road side network unit on the downlink channel.

[0056] (Clause 2) The method according to clause 1, the method comprising: reserving a sidelink resource on the second sidelink channel in the licensed frequency range.

[0057] (Clause 3) The method according to clause 1 or 2, the method comprising: determining a probability of collision on the first sidelink channel in the unlicensed frequency range; and reserving a sidelink resource on the second sidelink channel in the licensed frequency range depending on the probability of collision.

[0058] (Clause 4) A network infrastructure side network unit of a cell-based wireless communication network, the network infrastructure side network unit comprising: an antenna and a transceiver, the antenna and the transceiver being set up to receive, from a road side network unit, on an uplink channel, a scheduling request message for a first sidelink channel in an unlicensed frequency range; a processor, the processor being set up to determine a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit; wherein the antenna and the transceiver are set up to transmit the first scheduling grant message to the road side network unit on a downlink channel and to receive, from the road side network unit on the uplink channel, an indication that the assigned sidelink resource of the first sidelink channel is occupied; wherein the processor is set up to determine a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the road side network unit; and wherein the antenna and the transceiver are set up to transmit the second scheduling grant message to the road side network unit on the downlink channel.

[0059] (Clause 5) A method for operating a road side network unit of a cell-based wireless communication network, the method comprising: determining a message for transmitting to other road side network units; transmitting, to a network infrastructure side network unit, on an uplink channel, a scheduling request message for a first sidelink channel in an unlicensed frequency range; receiving, from the network infrastructure side network unit, on a downlink channel, a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road side network unit; determining that the assigned sidelink resource of the first sidelink channel is occupied; transmitting, to the network infrastructure side network unit, on the uplink channel, an indication that the assigned sidelink resource of the first sidelink channel is occupied; receiving, from the network infrastructure side network unit, on the downlink channel, a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel to the road side network unit; and transmitting the message to the other road side network units on the second sidelink channel.

[0060] (Clause 6) The method for operating a cell-based wireless communication network according to one of clauses 1 to 3 and clause 5.

[0061] (Clause 7) A road-side network unit of a cell-based wireless communication network, the road-side network unit comprising: a processor configured to determine a message for transmission to other road-side network units; an antenna and a transceiver configured to: transmit a scheduling request message for a first sidelink channel in an unlicensed frequency range to a network infrastructure-side network unit on an uplink channel, and receive a first scheduling grant message from the network infrastructure-side network unit on a downlink channel, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of the first sidelink channel to the road-side network unit; wherein the transceiver and / or the processor are configured to determine that the assigned sidelink resource of the first sidelink channel is occupied; wherein the antenna and the transceiver are configured to: transmit an indication that the assigned sidelink resource of the first sidelink channel is occupied to the network infrastructure-side network unit on the uplink channel, receive a second scheduling grant message from the network infrastructure-side network unit on the downlink channel, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel to the road-side network unit, and transmit the message to the other road-side network units on the second sidelink channel.

[0062] (Clause 8) A motor vehicle comprising the road-side network unit of clause 7.

[0063] (Clause 9) A method for operating a network infrastructure-side network unit of a cell-based wireless communication network, the method comprising: determining a first set of road-side network units within a cell of the network infrastructure-side network unit; determining a second set of road-side network units within the cell of the network infrastructure-side network unit, wherein the first and second sets are disjoint; receiving a first scheduling request message from a first road-side network unit of the first set on an uplink channel; determining a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of a first sidelink channel in an unlicensed frequency range to the first road-side network unit of the first set; transmitting the first scheduling grant message to the first road-side network unit on a downlink channel; receiving a second scheduling request message from a second road-side network unit of the second set on the uplink channel; determining a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the second road-side network unit of the second set; and transmitting the second scheduling grant message to the second road-side network unit on the downlink channel.

[0064] (Clause 10) The method of clause 9, comprising: determining a probability of collision on the first sidelink channel in the unlicensed frequency range; determining the first set of road-side network units within a cell of the network infrastructure-side network unit as a function of the determined probability of collision; determining the second set of road-side network units within a cell of the network infrastructure-side network unit as a function of the determined probability of collision.

[0065] (Clause 11) A network infrastructure-side network unit of a cell-based wireless communication network, the network infrastructure-side network unit comprising: a processor configured to: determine a first set of road-side network units within a cell of the network infrastructure-side network unit, and determine a second set of road-side network units within a cell of the network infrastructure-side network unit, wherein the first and second sets are disjoint; an antenna and a transceiver, the antenna and the transceiver being arranged to: receive a first scheduling request message on an uplink channel from a first road-side network unit of the first set; wherein the processor is configured to determine a first scheduling grant message, wherein the first scheduling grant message comprises an assignment of at least one sidelink resource of a first sidelink channel in an unlicensed frequency range to the first road-side network unit of the first set; wherein the antenna and the transceiver are arranged to transmit the first scheduling grant message on a downlink channel to the first road-side network unit, and receive a second scheduling request message on the uplink channel from a second road-side network unit of the second set; wherein the processor is arranged to determine a second scheduling grant message, wherein the second scheduling grant message comprises an assignment of at least one sidelink resource of a second sidelink channel in a licensed frequency range to the second road-side network unit of the second set; and wherein the antenna and the transceiver are arranged to transmit the second scheduling grant message on a downlink channel to the second road-side network unit.

Claims

1. A method for operating a network infrastructure side network unit BS of a cell-based wireless communication network CELL, the method comprising: - receiving (202) from a road side network unit UE1 on an uplink channel UL a scheduling request message BSR for a first sidelink channel SCI within a non-licensed frequency range NFLB; - determining (204) a first scheduling grant message Gl, wherein the first scheduling grant message Gl comprises an assignment of at least one sidelink resource PRB, MCS of the first sidelink channel SCI to the road side network unit UE1; - sending (206) the first scheduling grant message Gl to the road side network unit UE1 on a downlink channel DC; - receiving (208) from the road side network unit UE1 on the uplink channel UL an indication I that the assigned sidelink resource PRB, MCS of the first sidelink channel SCI is occupied; - determining (210) a second scheduling grant message G2, wherein the second scheduling grant message G2 comprises an assignment of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 within a licensed frequency range LFB to the road side network unit UE1; and - sending (212) the second scheduling grant message G2 to the road side network unit UE1 on the downlink channel DC.

2. The method according to claim 1, the method comprising: - reserving (804) a sidelink resource PRB, MCS on the second sidelink channel SC2 within the licensed frequency range LFB.

3. The method according to claim 1 or 2, the method comprising: - determining (802) a collision probability C on the first sidelink channel SCI within the non-licensed frequency range NFLB; and - reserving (804) a sidelink resource PRB, MCS on the second sidelink channel SC2 within the licensed frequency range LFB depending on the collision probability C.

4. A network infrastructure side network unit BS of a cell-based wireless communication network CELL, the network infrastructure side network unit comprising: - an antenna A_BS and a transceiver T_BS, the antenna and the transceiver being set up to receive from a road side network unit UE1 on an uplink channel UL a scheduling request message BSR for a first sidelink channel SCI within a non-licensed frequency range NFLB; - a processor P_BS, the processor being set up to determine a first scheduling grant message Gl, wherein the first scheduling grant message Gl comprises an assignment of at least one sidelink resource PRB, MCS of the first sidelink channel SCI to the road side network unit UE1; ​ - wherein the antenna A_BS and the transceiver T_BS are arranged to transmit the first scheduling grant message G1 to the road-side network unit UE1 on a downlink channel DC and to receive an indication I from the road-side network unit UE1 on the uplink channel UL that the allocated sidelink resources PRB, MCS of the first sidelink channel SC1 are occupied; - wherein the processor P_BS is arranged to determine a second scheduling grant message G2, wherein the second scheduling grant message G2 comprises an allocation of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 to the road-side network unit UE1 within a licensed frequency range LFB; and - wherein the antenna A_BS and the transceiver T_BS are arranged to transmit the second scheduling grant message G2 to the road-side network unit UE1 on the downlink channel DC.

5. A method for operating a road-side network unit UE1 of a cell-based wireless communication network CELL, the method comprising: - determining (302) a message P for transmitting to a further road-side network unit UE2; - transmitting (304) a scheduling request message BSR for a first sidelink channel SC1 within an unlicensed frequency range NLFB to a network infrastructure-side network unit BS on an uplink channel UC; - receiving (306) a first scheduling grant message G1 from the network infrastructure-side network unit BS on a downlink channel DC, wherein the first scheduling grant message G1 comprises an allocation of at least one sidelink resource PRB, MCS of the first sidelink channel SC1 to the road-side network unit UE1 ; - determining (308) that the allocated sidelink resources PRB, MCS of the first sidelink channel SC1 are occupied; - transmitting (310) an indication I to the network infrastructure-side network unit BS on the uplink channel UC that the allocated sidelink resources PRB, MCS of the first sidelink channel SC1 are occupied; - receiving (312) a second scheduling grant message G2 from the network infrastructure-side network unit BS on the downlink channel DC, wherein the second scheduling grant message G2 comprises an allocation of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 to the road-side network unit UE1 ; and - transmitting (314) the message P to the further road-side network unit UE2 on the second sidelink channel SC2.

6. A method for operating a cell-based wireless communication network CELL, the method comprising: - a method for operating a network infrastructure-side network unit BS of a cell-based wireless communication network CELL according to any one of claims 1 to 3; and - a method for operating a road-side network unit UE1 of a cell-based wireless communication network CELL according to claim 5.

7. A road-side network unit UE1 of a cell-based wireless communication network CELL, the road-side network unit comprising: - a processor P1, the processor being set up to determine a message P for transmitting to a further road-side network unit UE2; - an antenna A1 and a transceiver T1, the antenna and the transceiver being set up to transmit a buffer status report message BSR for a first sidelink channel SCI on an uplink channel UC within an unlicensed frequency range NLFB to a network infrastructure-side network unit BS and to receive a first scheduling grant message G1 from the network infrastructure-side network unit BS on a downlink channel DC, wherein the first scheduling grant message G1 comprises an assignment of at least one sidelink resource PRB, MCS of the first sidelink channel SCI to the road-side network unit UE1; - wherein the transceiver T1 and / or the processor P1 are set up to determine that the assigned sidelink resource PRB, MCS of the first sidelink channel SCI is occupied; - wherein the antenna A1 and the transceiver T1 are set up to transmit an indication I on the uplink channel UC to the network infrastructure-side network unit BS that the assigned sidelink resource PRB, MCS of the first sidelink channel SCI is occupied, to receive a second scheduling grant message G2 from the network infrastructure-side network unit BS on the downlink channel DC, wherein the second scheduling grant message G2 comprises an assignment of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 to the road-side network unit UE1, and to transmit the message P on the second sidelink channel SC2 to the further road-side network unit UE2.

8. A vehicle comprising a road-side network unit UE1 according to claim 7.

9. A method for operating a network infrastructure-side network unit BS of a cell-based wireless communication network CELL, the method comprising: - determining (502) a first group Gr1 of road-side network units UE1 within a cell C of the network infrastructure-side network unit BS; - determining (504) a second group Gr2 of road-side network units UE2 within the cell C of the network infrastructure-side network unit BS, wherein the first and the second group Gr1, Gr2 are disjoint; - receiving (506) a first buffer status report message BSR on an uplink channel UC from a first road-side network unit UE1 of the first group Gr1; - determining (508) a first scheduling grant message G3, wherein the first scheduling grant message G3 comprises an assignment of at least one sidelink resource PRB, MCS of a first sidelink channel SCI within an unlicensed frequency range NLFB to the first road-side network unit UE1 of the first group Gr1; - transmitting (510) the first scheduling grant message G3 on a downlink channel DC to the first road-side network unit UE1. - receiving (512) a second scheduling request message BSR from a second road-side network unit UE2 of the second group Gr2 on the uplink channel UC; - determining (514) a second scheduling grant message G4, wherein the second scheduling grant message G4 comprises an assignment of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 within a licensed frequency range LFB to the second road-side network unit UE2 of the second group Gr2; and - transmitting (516) the second scheduling grant message G4 to the second road-side network unit UE2 on a downlink channel DC; - determining (902) a collision probability C on the first sidelink channel SC1 within the cell C of the network infrastructure-side network unit BS; - determining the first group Gr1 of road-side network units UE1 within the cell C of the network infrastructure-side network unit BS depending on the determined collision probability C; - determining the second group Gr2 of road-side network units UE2 within the cell C of the network infrastructure-side network unit BS depending on the determined collision probability C.

10. A network infrastructure-side network unit BS of a cell-based wireless communication network CELL, the network infrastructure-side network unit comprising: - a processor P BS configured to determine a first group Gr1 of road-side network units UE1 within a cell C of the network infrastructure-side network unit BS and to determine a second group Gr2 of road-side network units UE2 within the cell C of the network infrastructure-side network unit BS, wherein the first and second groups Gr1, Gr2 are disjoint; - an antenna A BS and a transceiver T BS, the antenna and the transceiver being arranged to receive a first scheduling request message BSR from a first road-side network unit UE1 of the first group Gr1 on an uplink channel UC; - wherein the processor P BS is configured to determine a first scheduling grant message G3, wherein the first scheduling grant message G3 comprises an assignment of at least one sidelink resource PRB, MCS of a first sidelink channel SC1 within a non-licensed frequency range NLFB to the first road-side network unit UE1 of the first group Gr1; - wherein the antenna A BS and the transceiver T BS are arranged to transmit the first scheduling grant message G3 to the first road-side network unit UE1 on a downlink channel DC and to receive a second scheduling request message BSR from a second road-side network unit UE2 of the second group Gr2 on the uplink channel UC; - wherein the processor P BS is arranged to determine a second scheduling grant message G4, wherein the second scheduling grant message G4 comprises an assignment of at least one sidelink resource PRB, MCS of a second sidelink channel SC2 within a licensed frequency range LFB to the second road-side network unit UE2 of the second group Gr2; and - wherein the antenna A_BS and the transceiver T_BS are set up to transmit the second scheduling grant message G4 to the second road-side network unit UE2 on a downlink channel DC; - wherein the processor P_BS is set up to determine a collision probability C on the first sidelink channel SC1 within the unlicensed frequency range NFLB, to determine the first group Gr1 of road-side network units UE1 within the cell C of the network infrastructure-side network unit BS depending on the determined collision probability C, and to determine the second group Gr2 of road-side network units UE2 within the cell C of the network infrastructure-side network unit BS depending on the determined collision probability C.

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