ROAD-SIDE NETWORK NODE AND ITS MANAGEMENT PROCESS

Abstract

TITLE: Roadside Network Node and its Management Process A roadside network node (NNI, NN3, NNN5, NNN6) for an ad-hoc radio communication network (VANET) comprises a processor, memory, a radio module, and an antenna. The roadside network node is configured to: - determine the data to be transmitted over an ad-hoc radio channel, - determine or provide an ad-hoc time slot reserved for transmission over the ad-hoc radio channel, and - initiate data transmission over the ad-hoc radio channel during the ad-hoc time slot. Figure 3

Description

Title of the invention: Roadside network node and its management method. FIELD OF THE INVENTION

[0001] The present invention relates to a roadside network node and its management method. STATE OF THE ART

[0002] According to the prior art, it is known that vehicles can exchange information with other vehicles in their vicinity (V2V exchange: vehicle-to-vehicle exchange). Similarly, vehicles within a road infrastructure can communicate via a wireless link (V21 link: vehicle-to-infrastructure link). Likewise, vehicles can communicate wirelessly with a support server on the Internet (V2N: vehicle-to-network exchange) or with a pedestrian terminal (V2P: vehicle-to-person exchange). Overall, this communication can be referred to as vehicle-to-anything exchange (V2X exchange).

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

[0004] The first generation of V2X applications developed in the future will primarily concern road traffic applications. The main purpose is to provide the driver with information about the road environment. Vehicles periodically provide status information (generally position, speed, acceleration, etc.) and / or event information (emergency call, immobilized vehicle, traffic jam). This information is generally used locally in the form of text messages. For neighboring vehicles, this event-based information can be sent to a central network unit (base station, support).

[0005] DESCRIPTION AND ADVANTAGES OF THE INVENTION

[0006] The present invention aims to overcome the drawbacks of the prior art and to this end relates to a roadside network node for an ad-hoc radio communication network, the roadside network node comprising a processor, a memory, a radio module and an antenna, the roadside network node being configured to determine the data to be transmitted by an ad-hoc radio channel, determine or provide an ad hoc time slot reserved for transmission via the ad hoc radio channel and start a data transmission via the ad hoc radio channel during the ad hoc time slot.

[0007] In other words, the invention relates to a roadside network node for an ad-hoc radio communication network. The roadside network node comprises a processor, memory, a radio module, and an antenna. The roadside network node is configured to determine the data to be transmitted over an ad-hoc radio channel, to determine or provide an ad-hoc time slot reserved for transmission over the ad-hoc radio channel, and to initiate the transmission of this data over the ad-hoc radio channel during this ad-hoc time slot.

[0008] Advantageously, the network node, on the road side, transmits semi-synchronous data over the radio transmission of the cellular radio communication network, thereby reducing or eliminating interference with the cellular radio communication network. A coexistence mechanism is provided to allow the ad hoc radio communication network and the cellular radio communication network to operate in the same unassigned or overlapping frequency range.

[0009] According to an advantageous development, the roadside network node is configured to synchronize a local clock to a common time source signal, determine the foreseeable boundaries of a known a priori duration of a frame unit, specifically determine subframe boundaries of a cellular radio communication network as a function of a clock signal from the local clock, determine the state of the adhoc radio channel and determine the occupancy of this adhoc radio channel as a function of the foreseeable boundaries and as a function of the state of the adhoc radio channel and determine the adhoc time slice as a function of the occupancy.

[0010] The occupancy pattern is evaluated to discriminate between ad hoc traffic and other traffic occupying the ad hoc radio channel. Furthermore, the ad hoc time slot provides a means of reducing interference between the ad hoc channel and the sidelink channel of the cellular radio communication network. Advantageously, a pre-configured resource group is avoided by reducing the upstream configuration.

[0011] According to an advantageous development, the network node, on the road side, is configured to determine occupancy as the first occupancy of the adhoc radio channel by adhoc traffic if the state indicates contiguous transmission with at least one unspecified transmission boundary as a limit.

[0012] Advantageously, determining the first occupancy makes it possible to differentiate between ad hoc and non-ad hoc traffic.

[0013] According to an advantageous development, the roadside network node is configured to determine occupancy as the second occupancy of the ad-hoc radio channel with non-adhoc traffic if the state indicates contiguous transmission with the two transmission limits which are assumed to be borders.

[0014] Advantageously, the determination makes it possible to differentiate between ad hoc traffic and non-ad hoc traffic.

[0015] According to an advantageous development, the ad hoc time slot is provided by a pre-configured resource group.

[0016] Advantageously, a preconfigured resource group or a subset of an LTE-V resource group is used. The resource group allows the network node, on the route side, to transmit data according to a time-division multiplexing scheme. This allows coexistence with other techniques such as LTE-V. Furthermore, upstream processing is eliminated.

[0017] According to an advantageous development, the network node, on the road side, is configured to synchronize the local clock to the common time source signal, to determine the appropriate time slice based on the clock signal emitted by the local clock and based on the global startup time reference of the preconfigured resource group.

[0018] According to an advantageous embodiment, the roadside network node is configured to start a data transmission via the adhoc radio channel during one of the adhoc time slots by omitting the start during a guard interval at the end of the adhoc time slot.

[0019] Advantageously, omitting the start of the ad-hoc transmission during the guard interval means that few or no ad-hoc transmissions interfere with transmissions in the non-ad-hoc time slot, which corresponds to a lateral link time slot followed by the ad-hoc time slot.

[0020] According to another embodiment, the invention relates to a method for managing a network node, on the road side. The method consists of determining the data to be transmitted via an ad hoc radio channel, determining or providing an additional time slot reserved for transmission via the ad hoc radio channel, and continuously starting the data transmission via the ad hoc radio channel during the ad hoc time slot.

[0021] The present invention will be described in more detail below, using examples of roadside network nodes and a management method shown in the accompanying drawings in which:

[0022] [Fig. 1] is a schematic perspective view of an example of a traffic situation,

[0023] [Fig. 2A] schematically shows a roadside network unit,

[0024] Figure 2B schematically shows a group of resources,

[0025] Figure 3 schematically shows a flowchart for managing the node, road side,

[0026] Figure 4 schematically shows the occupancy of a radio link channel transversal and another radio channel,

[0027] Figure 5 schematically shows a flowchart for managing the node, road side,

[0028] Fig. 6 schematically shows another flowchart for managing the node, side road,

[0029] Fig. 7 schematically shows another flowchart for managing the node, on the road side, and

[0030] [Fig.8] schematically shows another node management flow, on the road side.

[0031] Figure 1 is a schematic perspective view of an example of a road traffic situation at an intersection 2 equipped with traffic lights. Each of the vehicles VI, V3 has a network node NNI, NN3 forming a VANET ad hoc radio communication network. Each of the vehicles V2, V4 has a network node NN2, NN4 forming a CNET cellular radio communication network. A vehicle V5 and an intersection traffic light TL have a network node NN5, NN6. These nodes are configured to participate in the VANET ad hoc radio communication network and the CNET cellular radio communication network. Other fixed infrastructure entities, in addition to the traffic lights, may have a network node such as NNI, NN2, or NN6.

[0032] Each of the network nodes NNI, NN2, NN3, NN4, NN5, NN6, and NN7 comprises a data bus BI, B2, B3, B4, B5, B6, B7 connecting at least one processor PI, P2, P3, P4, P5, P6, P7, one memory M1, M2, M3, M4, M5, M6, M7, and one satellite receiver GI, G2, G3, G4, G5, G6, G7. The network nodes NNI, NN2, NN3, NN4, NN5, and NN6 are roadside network nodes, meaning that these network nodes are installed in a vehicle or road infrastructure. The network node NN7 is an infrastructure network node, meaning that this node is configured to manage network functions. The GI, G2, G3, G4, G5, G6 and G7 satellite receivers are configured to receive at least one TS satellite signal, for example, a GPS (Global Positioning System) signal from an Earth satellite S.Each of the memories M1, M2, M3, M4, M5, M6, M7 contains a computer program that applies the processes described in the description when these processes are executed by the corresponding processor PI, P2, P3, P4, P5, P6, P7. Alternatively or in addition, the processors PI, P2, P3, P4, P5, P6, P7 are implemented as ASIC processors. Each of the network nodes NNI, NN3 includes a radio module Cl, C3 configured for the transmission and reception of radio signals according to the ad hoc VANET radio communication network.

[0033] Each of the radio modules C1, C3 is connected to an antenna A1, A3. Each of the network nodes NN2, NN4 has a radio module D2, D4 configured for the transmission and reception of radio signals according to the CNET cellular radio communication network. Each of the radio modules D2, D4 is connected to an antenna A2, A4. Each of the network nodes NN5, NN6 has a radio module D5, D6 configured for the The transmission and reception of radio signals is controlled by the CNET cellular radio communication network. Radio modules C5 and C6 are configured for this purpose. Each radio module D5 and D6 is connected to an antenna A5d and A6d. Each radio module C5 and C6 is connected to an antenna A5c and A6c.

[0034] National administrations such as the Federal Network Agency of the Federal Republic of Germany establish a frequency utilization plan with licenses for the various network operators. The network operator is authorized, within the scope of the assigned license, to connect infrastructure network nodes and network nodes within an authorized frequency range or frequency spectrum. Conversely, there are frequency ranges or frequency spectra that are not allocated to any network operator and that may be used freely under certain conditions, such as, for example, dedicated power transmission and reception.

[0035] The VANET network has an ad-hoc radio channel AHCH. The CNET network has a sidelink radio channel, also called a sidelink radio channel SLCH. Each SLCH sidelink radio channel and each AHCH ad-hoc radio channel is a wireless WM transmission means used to pass the physical layer PHY, the protocol data units PDU, between two or more network nodes. In both the VANET and CNET networks, the radio signals are transmitted using the same or overlapping unassigned frequency range (uFR). Uncoordinated use of the SLCH and AHCH channels would lead to the degradation of at least one of the two SLCH and AHCH channels.

[0036] The infrastructure network node NN7 has a network interface 17 for accessing other network nodes, for example, a backhaul network (intermediate network or feeder network). The infrastructure network node NN7 can also be called a "base station" or conventionally abbreviated as eNodeB. The infrastructure network node NN7 is connected to a fixed antenna A7 for transmitting data in the downlink channel DC and for receiving data via the uplink channel UC. The antenna A7 has, for example, a number of antennas designed as a remote radio head (RRH). The infrastructure network node NN7 can be implemented in a distributed manner, for example, in the context of virtualization; it can consist of a set of separate network nodes. The infrastructure network node NN7 and the route-side network nodes NN2, NN4, NN5, and NN6 are configured, for example, according to the LTE-V2X protocol.

[0037] The infrastructure network node NN7 and the antenna A7 feed a radio cell CL covering the road-side network nodes NN5 and NN4 and capable of communicating with the infrastructure network node NN7. The network nodes NN2 and NN5 are not located in the CL radio cell and are out of coverage relative to the NN7 infrastructure network node and cannot communicate directly with it.

[0038] The SLCH sidelink radio channel and a sidelink are generally defined, for example, by the 3GPP TS 36.300 V 14.2.0 (2017-03) protocol, which is referenced herein. Network nodes NN2, NN4, NN5, and NN6 are configured according to the 3GPP TS 36.300 V 14.2.0 (2017-03) protocol. The sidelink includes a sidelink search and V2X sidelink communication (V2X vehicle-to-any-object). The sidelink uses uplink resources and a physical channel structure analogous to the uplink. The sidelink thus differs from the uplink with respect to the physical channel.

[0039] Sidelinking is limited to individual cluster transmission for physical sidelink channels. Furthermore, sidelinking uses a gap with a symbol at the end of each sidelink subframe. For V2X sidelink communication, the physical sidelink control channel, PSCCH, and the shared physical sidelink channel, PSSCH, exchange data within the same subframe.

[0040] The processing of the physical layer of transport channels in the sidelink differs from uplink transmission in the following steps: scrambling: for PSDCH, sidelink physical search channel, and PSCCH, scrambling is not specific to the network entity; modulation: 64-QAM and 256-QAM are not carried by the sidelink (QAM: quadrature amplitude modulation). The term PSCCH refers to sidelink resources and other transmission parameters used by the respective network node for the PSSCH channel.

[0041] For PSDCH, PSCCH, and PSSCH demodulation, reference signals, analogous to uplink demodulation reference signals, are transmitted in the fourth symbol of the slice; these signals are transmitted in the normal cyclic prefix (normal CP) and in the third symbol of the slice in the extended cyclic prefix CP. The length of the sidelink demodulation reference signal sequence corresponds to the size (number of subcarriers) of the associated resource. For V2X sidelink communication, the reference signals are transmitted in the 3rd and 6th symbols of the first slice and in the 2nd and 5th symbols of the second slice in the cyclic prefix CP. For PSDCH and PSCCH, the reference signals are generated based on a fixed basic sequence, a cyclic offset, and an orthogonal cover code.For V2X sidelink communication, the cyclic phase shift of PSCCH is chosen randomly for each transmission.

[0042] For sidelink radio channel measurements, the following operations are available on the network node side: sidelink reference signal power reception (S-RSRP); sidelink search reference signal power reception (SD-RSRP); PSSCH reference signal power received (PSSCH-RSRP); signal strength indicator for sidelink reference signals (S-RSSI).

[0043] A sidelink resource group can be pre-configured, semi-static, or dynamic, and it corresponds to a set of radio resources for performing a sidelink transmission over the SLCH sidelink radio channel. A network node that has a sidelink communication in Mode 2 (uncovered case) automatically selects a resource from a resource group range configured by the infrastructure network node NN7 or a head end of a sidelink cluster in advance. A network node in a sidelink communication in Mode 1 (covered case) selects a resource that has been programmed by the infrastructure network node NN7.

[0044] Each of the network nodes NNI, NN3, NN5, NN6 is configured, for example, according to the IEEE 802.1 IP standard, in particular IEEE 802.11 p-2010 of July 15, 2010, cited herein by way of reference. The IEEE 802.1 IP PHY and MAC standards provide services for upper-layer protocols for dedicated short-range DSRC communications in the United States and for cooperative ITS, C-1TS, in Europe. The network nodes NNI, NN3, NN5, NN6 communicate directly with each other via the ad hoc radio channel AHCH in the unlicensed frequency range. The ad hoc radio channel AHCH is governed by the CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) protocol by the radio modules C1, C3, C5, C6.

[0045] The network node NNI is configured to transmit data via the AHCH ad-hoc radio channel, and the network node NN3 can receive data. All network nodes within the radio signal's reception range, such as the network node NN3, can receive such data. The AHCH ad-hoc radio channel and ad-hoc radio channels in general, as well as the VANET ad-hoc radio communication network, are described by way of example in the IEEE Standard "802.1 IP-2010 - IEEE Standard for Information Technology — Local and Metropolitan Area Networks —" Specifies Part 1.1: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 6: Wireless Access in Vehicular Environments. The IEEE 802.1 IP standard extends the IEEE 802.1 IP WLAN protocol. The purpose of the IEEE 802.IEEE 802.1 IP aims to establish a radio technology for passenger vehicles and to provide a reliable interface for intelligent transportation systems (ITS). The IEEE 802.1 IP standard also forms the basis for this. Dedicated Short Range Communication (DSRC) in the 5.85-5.925 GHz frequency band. To avoid confusion with the European version DSRC, the term ITS-G5 will be used rather than DSRC, particularly in Europe.

[0046] For access to the AHCH ad hoc radio channel, network nodes NNI NN3, NNN5, and NN6 use distributed channel access, enhanced EDCA, and the listen-before-talk (LBT) procedure. The LBT procedure applies a backoff procedure before transmitting on the AHCH ad hoc radio channel. First, network node NNI, NN3, NN5, or NN6 listens and waits until the AHCH ad hoc radio channel is available for a specified period of time; this AIES time period is called the AIES inter-frame interval arbitration. The AHCH ad hoc radio channel is detected as free if the power level is below a first threshold, such as 62 dBm, and no ad hoc preamble is detected if the power level is above a second threshold, such as -82 dBm. The ad hoc radio channel is active if it is not detected as free.

[0047] If the AHCH ad hoc radio channel is detected as free during the AIFS time period, the backoff procedure begins. A backoff clock is started with a random number that is a multiple of a 9 µs time slice. The random number is determined within a contention window. The random backoff clock is decreased by one when the AHCH ad hoc radio channel is detected as empty. For each time slice, the AHCH ad hoc radio channel is detected as active, and the random backoff clock remains at the same value as before.

[0048] Network node NNI, NN3, NN5, or NN6 obtains a TXOP transmission opportunity at the end of the backhoff clock. If network node NNI, NN3, NN5, or NN6 detects that the ad hoc radio channel is free, it will transmit the data provided that the TXOP transmission opportunity has not yet expired.

[0049] The receiving network node among the network nodes NNI, NN3, NN5 and NN6 sends an acknowledgment to the sending node, upon receipt of the data if the data has not been transmitted in extended mode.

[0050] The standard "ETSI EN 302 663 V 1.2.0 (2012-11)" referenced herein describes both the lowest layers of the ITS-G5 protocol (ITS G5: Intelligent Transportation System operating in the 5 GHz frequency band), namely the physical layer and the data link layer. Radio modules Cl, C3, C5, and C6, for example, implement the two lowest layers and the corresponding functions according to "ETSI TS 102 687 VI. 1.1 (2011-07)" for use with the ad hoc radio channel. The following unlicensed frequency bands are available in Europe for use as the AHCH ad hoc radio channel; they are part of the unlicensed NLFB frequency band:

[0051] 1) ITS-G5A for safety applications in the frequency range 5.875 GHz-5.905 GHz,

[0052] 2) ITS-G5B for non-security applications in the 5.855 frequency range GHz-5.875 GHz, and

[0053] 3) ITS-G5D for ITS applications in the frequency range 5.055 GHz-5.925 GHz. ITS-5G enables communication between two network units (UEI and UE2) outside the context of a base station. ITS-5G allows for the immediate exchange of data frames and eliminates the need for higher-level management to construct a network.

[0054] The standard "ETSI TS 102 687 VI. 1.1 (2011-07)", reproduced here for reference, describes the ITS-G5 mechanism as a "Decentralized Congestion Control Mechanism". Among other things, the AHCH ad hoc radio channel serves as security for the exchange of traffic and efficient data traffic. The radio modules C1, C3, C5, and C6, for example, perform functions such as those described in the standard "ETSI TS 102 687 V 1.1.1 (2011-07)". The applications and services in the ITS-G5 system are based on the cooperative behavior of the roadside network nodes that constitute the VANET ad hoc network (VANET: Vehicular Ad Hoc Network). The VANET ad hoc network enables time-critical road traffic applications that require rapid information exchange to inform and assist the driver and / or vehicle in a timely manner.To ensure the proper functioning of the VANET ad hoc network, a decentralized congestion control (DCC) mechanism is used for the AHCH ad hoc radio channel for its ITS-G5 application. The DCC mechanism has features that reside in multiple layers of its ITS architecture. The DCC mechanism is based on knowledge about the channel. Channel state information is obtained through channel testing. Channel state information can be obtained through the TPC (Transmission Power Control), TRC (Transmission Rate Control), and TDC (Transmission Data Rate Control) processes. These processes determine channel state information relative to the thresholds of received signal levels or the preamble information from detected packets.

[0055] The VANET ad hoc radio communication network and the CNET cellular radio communication network differ in several respects; differences between the two techniques already exist in the encoding / decoding chain and thus in the modulation and encoding schemes. This does not allow for successful decoding of a received signal using another technique. Different reference symbols are used in different ways: sidelink reference symbols are transmitted to certain radio resources during transmission via the SLCH sidelink radio channel. Furthermore, ad hoc reference symbols are transmitted at the beginning of a transmission via the AHCH ad hoc radio channel. In addition, transmission via the The SLCH sidelink radio channel requires synchronized participation from network nodes to correctly decode the received signal. The AHCH ad-hoc radio channel allows for connectionless, asynchronous signal transmission.

[0056] In the traffic state as described, the NNI-NN6 network nodes are positioned so that the radio power of each NNI-NN6 network node is sufficient to reach another NNI-NN6 network node. Thus, transmissions through the overlapping AHCH and SLCH channels can negatively influence each other. One purpose of this description is to advantageously reduce this mutual influence.

[0057] As an example, vehicle V5 is an emergency vehicle in operation and it communicates its emergency status by an M5T message via the ad-hoc radio channel ADCH and the lateral link radio channel T L. Network node NN5 is configured to transmit a message via the lateral link radio channel SLCH and / or the ad-hoc radio channel AHCH, which can be received by network node NN6. Since both network nodes NN5 and NN6 have radio modules C5, D5, C6, and D6 for both CNET and VANET networks, both techniques are accessible. Network nodes NN5 and NN6 can also be called gateway nodes. The lateral link radio channel SLCH between network nodes NN5 and NN6 operates in distributed mode.

[0058] Depending on the message received, the intersection signal TL at the intersection is activated for cross traffic. When the signal turns red, the intersection signal communicates its red status in an MTI message via the ad hoc radio channel AHCH to vehicle VI so that it reduces its speed. Vehicle VI is traveling at a speed of 100 km / h and communicates its speed in an M13 message via the ad hoc radio channel ADCH to other vehicles such as vehicle V3.

[0059] Network node NN2 is configured to transmit an M2T message via the SLCH sidelink radio channel to network node NN6. Since both network nodes NN2 and NN6 are outside the CL radio cell, access to the SLCH sidelink radio channel is not controlled by an infrastructure network node. The SLCH sidelink radio channel between nodes NN2 and NN6 operates in distributed mode.

[0060] Network node NN4 is configured to transmit an M45 message via the SLCH sidelink radio channel to network node NN5. Since both network nodes NN4 and NN5 belong to the radio cell CL, access to the sidelink radio channel is controlled by infrastructure network node NN7. Between network nodes NN4 and NN5, the SLCH sidelink radio channel operates in mode 1, or managed mode, meaning that infrastructure network node NN7 controls the transmission on the SLCH sidelink radio channel. corresponding programming of SA assignments in the DC downlink channel. The infrastructure network node NN7 includes an organizer that determines the SA assignments for the SLCH sidelink radio channel. SA assignments are command signals transmitted via the DC downlink channel that indicate which sidelink radio resources should be used by network nodes NN4 and NN5 to transmit data over the sidelink. SA assignments are determined to minimize interference. This is crucial under heavy network load, as the organizing unit ensures Quality of Service (QoS), which typically encompasses data rates, data reliability, packet fault reporting, and delays to different applications, by allocating sidelink radio resources to each of the NN4 and NN5 network nodes based on the application's QoS requirements.Data transmissions associated with SA order assignments can occupy adjacent RB resource blocks within the same subframe or non-adjacent RB resource blocks, depending on the latency required by the application. Ordering and command by the NN7 infrastructure network node can only occur in areas where NN7 node signals are available (within coverage). In this mode, ordering and radio traffic interference management are assisted by the NN7 infrastructure network node, with command signaling handled by the DC downlink channel. The NN7 infrastructure network node dynamically allocates resources (typically time and frequency range) to each network node for the sidelink.

[0061] Since the services must be available anywhere, including in areas where there is no network coverage from an available NN7 network infrastructure node, there is another configuration or development mode for the SLCH sidelink radio channel, namely the distributed mode. In the distributed mode, the ordering and interference management of radio traffic is supported by distributed algorithms implemented between the network nodes, for example, NN2 and NN5. These distributed algorithms are based on semi-persistent transmission detection, taking into account that the radio traffic generated by each network node NN2, NN5 is generally periodic in nature. This technique makes it possible to detect the occupancy of the radio resource and to estimate future congestion.This optimizes the use of the lateral link by increasing resource separations between the emitter and the resource overlapping nodes. Furthermore, a mechanism in which resource allocation depends on geographic information can reduce the number of normal nodes competing for the same resources, thus reducing the risk of collisions. The allocation method. Primarily used in out-of-coverage scenarios, it is also called "cell-unsupported mode." Consequently, the CNET cell-supported communication network provides both cell-supported mode (within coverage) and distributed mode (out of coverage), even though, outside of coverage, the CNET network is designed as a cellular radio communication network.

[0062] Both modes are designed to use a dedicated carrier for radio communications, meaning that the spectrum band is used only for V2V communications based on a direct sidelink. The design allows for different bandwidths (generally 10 MHz or multiple 10 MHz bands). In both cases, the Global Navigation Satellite System (GNSS) is used for synchronization.

[0063] In the description, reference is made to a single uplink channel and a single downlink channel. For example, the uplink channel and the downlink channel have their respective subchannels. Different channels can be used in the uplink and downlink. The same applies to the sidelink radio channel SLCH and the ad-hoc radio channel AHCH.

[0064] Figure 2a schematically shows the first network node, road-side, NNI. In addition to the embodiment of [Fig. 1], the network node NNI has a local clock CLI. The local clock

[0065] CLI is synchronized by the satellite receiver GI, which receives the satellite signal representing a common time source signal for other network nodes on the route side. In another embodiment, the CLI local clock is synchronized to a different type of common time source signal, for example, a clock synchronization protocol (PT P signal). Synchronizing the local clock consists of: setting a time reference to a global reference based on the common time source signal, and setting the local clock frequency and phase based on the common time source signal.

[0066] Figure 2b schematically shows a resource group RP. The resource group RP comprises at least one sidelink time slice TS, providing the radio resources to be reserved for transmission over the sidelink radio channel. This information implicitly indicates a resource group cycle, which corresponds to a resource group repetition rate. This information implicitly indicates that the time-bound radio resources can be used for the ad hoc radio channel. Furthermore, the resource group has a starting global time reference tG, which indicates a time point relative to global time. This time point indicates a global time scale corresponding to the resource group.

[0067] Figure 3 schematically shows a flowchart of the operation of a network node with ad hoc capacity NNI, NN3, NN5 or NN6 of Figure 1. The data to The transmission over an ad-hoc radio channel is determined in step 302. An ad-hoc time slot reserved for transmission over the ad-hoc radio channel is determined or provided in step 304. Data transmission over the ad-hoc radio channel starts during an ad-hoc time slot in step 306. The ad-hoc time slot is reserved for transmission over the ad-hoc radio channel; the network node with ad-hoc characteristics cannot use other time slots, other than the ad-hoc time slot.

[0068] Figure 4 schematically shows the occupancy of the sidelink radio channel (TS sidelink) and the ad-hoc radio channel (TS adhoc). The RP resource group includes information about the sidelink TDM channel and the ad-hoc TDM channel (TDM: Time Division Multiplexing), each channel having time slots indicating exclusive reservation for the respective channel. Therefore, the RP resource group contains a set of radio resources available for transmission via the sidelink radio channel and for transmission via the ad-hoc radio channel in time-division multiplexed access.

[0069] The SLTx blocks indicate transmission via the SLCH sidelink radio channel, and the AHtx block indicates transmission via the AHCH ad-hoc radio channel. After an SLTx transmission via the sidelink radio channel, according to Section 404, one of the network nodes accessing the ad-hoc radio channel detects that the channel is free. Section 406 shows that if the backoff clock of the "listen before you talk" procedure reaches zero, the network node transmits the data via the AHCH ad-hoc radio channel according to the AHTxl and AHTx2 blocks.

[0070] During the sidelink time slots of the sidelink TDM channel, each of the network nodes with a sidelink characteristic determines the sidelink time slot available for transmission via the sidelink radio channel. The TDM channel differs from a radio channel in that the radio channel transmits data using physical radio resources. The TDM channel establishes time slots of physical radio resources available for the sidelink radio channel or the ad hoc radio channel.

[0071] In a sidelink time slot (TS), sidelink characteristic network nodes transmit synchronized SLTx data via the sidelink radio channel SLCH. Adhoc characteristic network nodes are permitted to transmit AHTxl and AHTx2 data within an adhoc time slot (TS adhoc). The adhoc characteristic network node receives or determines the guard interval GI at the end of the adhoc time slot (TS adhoc) when adhoc transmission initiation is not permitted. Transmission initiation via the adhoc radio channel ADCH is permitted within the T_start time slot. The guard interval GI represents the maximum transmission duration. via the ad-hoc radio channel. Thus, from time t_3_l until the end of the ad-hoc time slice TS, no transmission is permitted via the ad-hoc radio channel. Time t_3_l is determined as the limit of the next subframe tsub minus the ad-hoc frame time, which is the maximum or average frame time on the ad-hoc radio channel.

[0072] Figure 5 schematically shows a flowchart of the node, on the road side, with an ad-hoc characteristic. When the network node with an ad-hoc characteristic determines data to be transmitted in step 502, it checks in step 504 whether the network node is in an ad-hoc time slot (TS) but outside the guard interval. If so, the network node listens to the ad-hoc radio channel in step 506. If the ad-hoc radio channel is determined to be free in step 508, then the network node begins transmitting the data via the ad-hoc radio channel in step 524. In step 526, the transmission via the ad-hoc radio channel is terminated.

[0073] If the network node determines in step 508 that the adhoc radio channel is active, a backhoff clock is initialized with a random number in step 510. The network node checks in step 512 whether it is in an adhoc time slice (TS) but outside the guard interval. If so, the network node listens to the adhoc radio channel in step 514. After the adhoc channel has been determined to be free in step 516, the backhoff clock is decremented by one in step 518. If the backhoff clock is greater than zero, the process continues with step 512. If the backhoff clock reaches zero, the network node determines whether there is a guard interval. If so, the procedure continues with step 512 by removing the transmission start in the guard interval at the end of the adhoc TS adhoc time slice.If the network node is outside the guard interval, it starts transmission at the date of step 524.

[0074] Figure 6 schematically shows another flowchart of operation for one of the route-side nodes with ad-hoc characteristics as shown in Figure 1. According to step 602, the local clock is synchronized to the common time source signal. According to step 604, the predicted limits of the a priori known duration of a frame unit, for example, 1 ms of subframe in the cellular radio communication network, are determined based on the local clock signal. Thus, the subframe limits that fall within a full millisecond are known to the network node. In step 604, the free / active state of the ad-hoc radio channel is determined for a period of time. Thus, according to step 608, the occupancy of the ad-hoc radio channel is determined based on the predicted limits and the state of the ad-hoc radio channel. To fall within the predicted limits, an interval is defined around the exact time.A subframe limit for the cellular radio communication network is planned for each complete duration of . 1 ms. Thus, according to step 610, the appropriate time slot is determined based on occupancy.

[0075] Figure 7 schematically shows another flowchart of operation of one of the route-side nodes with adhoc characteristics according to Figure 1. The route-side node NNI teaches the resource group RP, or at least a part thereof, to observe the adhoc channel and to compare the channel listening results to a clock signal from the local clock. The local clock is synchronized to the common time source signal. In step 702, the STAT state is determined based on received energy measurements on the adhoc radio channel. Initial occupancy of the adhoc radio channel with adhoc traffic is determined in step 704. If the STAT state indicates a known TXA or TxB transmission with at least one transmission boundary—the start or end—not expected as a limit, for example, for a full or nearly full microsecond, then the observed TxA, TxB transmission is considered appropriate traffic.In step 706, a second occupancy O2 of the adhoc radio channel is determined with non-adhoc traffic. If the state indicates continuous transmission with two defined boundaries as the expected boundary, then the observed transmission is considered non-adhoc traffic. According to step 708, a minimum number of adhoc time slots is determined. Thus, for step 710, a minimum adhoc time slot is determined. In step 712, the adhoc time slot TS is determined based on the minimum of the time slots. In the example presented, the sidelink and adhoc time slots TS are determined to be greater than their respective minimum time slots since there is sufficient free time between the determined minimum time slots.

[0076] In one embodiment, step 712 further includes a resource group duration, estimated Trp; and an estimated start trp_start of the resource group cycle. The start trp_start is the time when the resource group starts. The next state of the start trp_start indicates the next ad-hoc time slice Ts adhoc. In one embodiment, steps 706 and 710 are omitted, and step 712 estimates the ad-hoc time slice TS adhoc without knowing the non-adhoc traffic. In another embodiment, steps 704 and 708 are omitted, and step 712 estimates the ad-hoc time slice TS adhoc without knowing the ad-hoc traffic.

[0077] Figure 8 schematically shows another flowchart of the operation of the roadside node NNI. In step 802, the local clock is synchronized to the common time source signal. In step 804, the ad-hoc time slice TS is determined based on the clock signal, the global start time tG which is part of the preconfigured resource group, and the radio time resources that are not allocated to the sidelink radio channel. to make it an ad-hoc radio channel. Thus, the network node, on the route side, with ad-hoc characteristics can determine the ad-hoc time slice TS adhoc as a function of the global start time and the time offset TO relative to the ad-hoc time slice.

Claims

Demands

1. A network node, roadside, (NNI, NN3, NNN5, NNN6) for an ad-hoc radio communication network (VANET), the network node, roadside, (NNI, NN3, NNN5, NNN6) comprising a processor, memory, radio module, and antenna, the network node being configured to: - determine the data to be transmitted over an ad-hoc radio channel, - determine or provide an ad-hoc time slot reserved for transmission over the ad-hoc radio channel, and - initiate data transmission over the ad-hoc radio channel during the ad-hoc time slot, characterized in that it is configured to: - synchronize a local clock to a common time source signal, - determine the foreseeable limits of a duration known a priori for a particular frame unit, - determine subframe limits of a cellular radio communication network based on a clock signal from the local clock, - determine the state of the ad-hoc radio channel,- determine the occupancy of the ad hoc radio channel based on foreseeable boundaries and the state of the ad hoc radio channel, and - determine the ad hoc time slot based on the occupancy, and - determine the occurrence of a first occupancy of the ad hoc radio channel by ad hoc traffic if the state indicates contiguous transmission through at least one transmission boundary that is not expected to be a boundary.

2. Roadside network node (NNI, NN3, NNN5, NNN6) according to claim 1, network node characterized in that it is configured to: - determine occupancy as second occupancy of the adhoc radio channel by non-adhoc traffic if the state indicates contiguous transmission with the two transmission limits provided as boundary.

3. Roadside network node (NNI, NN3, NNN5, NNN6) according to claim 1, characterized in that The ad hoc time slot is provided by a pre-configured group of resources.

4. Roadside network node (NNI, NN3, NNN5, NNN6) according to claim 3, network node characterized in that it is configured to: - synchronize the local clock to the common time source signal, - determine the ad hoc time slice as a function of the clock signal of the local clock and as a function of a global starting reference time of the preconfigured resource group.

5. Roadside network node (NNI, NN3, NNN5, NNN6) according to any one of the preceding claims, network node characterized in that it is configured to: - start a data transmission via the adhoc radio channel during one of the adhoc time slots by omitting the start during a guard interval provided at the end of the adhoc time slot.

6. A method for managing a roadside network node (NNI, NN3, NNN5, NNN6), characterized in that it consists of: - determining the data to be transmitted via the ad-hoc radio channel, - determining or providing an ad-hoc time slot reserved for transmission via the ad-hoc radio channel, and - starting the transmission of data via the ad-hoc radio channel during the ad-hoc time slot, - synchronizing a local clock to a common time source signal, - determining the foreseeable limits of a duration known a priori for a particular frame unit, - determining subframe limits of a cellular radio communication network as a function of a clock signal from the local clock, - determining the state of the ad-hoc radio channel, - determining the occupancy of the ad-hoc radio channel as a function of the foreseeable limits and as a function of the state of the ad-hoc radio channel, and - determining the ad-hoc time slot as a function of the occupancy.and - determine the occurrence of a first occupation of the ad hoc radio channel by ad hoc traffic if the state indicates contiguous transmission, by at least one transmission boundary that is not intended to be a boundary.

Images