EP4327487A1

EP4327487A1 - Apparatus and method for intrinsically analysing the connection quality in radio networks with network-coded cooperation

Info

Publication number: EP4327487A1
Application number: EP22717634.4A
Authority: EP
Inventors: Andreas Frotzscher; Hannes ELLINGER; Oliver Haala; Jürgen HUPP; Frank Burkhardt; Kirsten Schuh
Original assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Current assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority date: 2021-04-23
Filing date: 2022-04-21
Publication date: 2024-02-28
Also published as: US20240048496A1; WO2022223713A1; EP4080798A1

Abstract

An apparatus (100) for determining a transmission quality in a communication network is provided. A first network unit (151) of the communication network is configured to carry out a first data transmission by transmitting first data to be sent by the first network unit (151) in such a manner that a first data packet depends on the first data. A second network unit (152) of the communication network is configured to carry out a second data transmission by transmitting second data to be sent by the second network unit (152) in such a manner that the second data are combined with the first data in a second data packet. The apparatus (100) comprises a receiving unit (110) which is designed to receive the second data transmission. The apparatus (100) also comprises an evaluation unit (120) which is designed to determine a first quality of the first data transmission and/or a second quality of the second data transmission by virtue of the evaluation unit (120) evaluating the second data packet.

Description

Device and method for the intrinsic analysis of the connection quality in radio networks with network-coded cooperation

description

The application relates to a device and a method for the intrinsic analysis of the connection quality in radio networks with network-coded cooperation.

High demands are placed on radio systems, particularly in industrial applications with fast response times or high security or availability specifications, in terms of packet loss rate, data rate or transmission latency in bidirectional transmission. Examples in which data is to be transmitted via a radio system with a fast reaction time and high security are data from sensors or actuators in mobile scenarios or data from (motor) controls.

In order to implement a deterministic timing behavior in radio transmission, scheduling methods or time-division multiplex methods (Time Division Multiple Access TDMA) are usually used. In the case of error-free transmission, this leads to a deterministic transmission latency or cycle time of the radio system. If the transmission is disrupted, action must be taken. However, these measures must not violate the time requirements for the transmission, since external control systems would otherwise react to the transmission disruption, for example with an emergency operation or a shutdown of the machine.

Measures to increase robustness are usually implemented in various ways, for example by adapting the modulation method used, or by adapting the channel coding to improve an individual connection (link), or by using a retransmission or ARQ/HARQ method a packet repetition within the cycle time, or through antenna diversity, to utilize several transmission paths with multipath propagation.

A further measure to increase robustness consists in relaying and in cooperative methods (Cooperative Communication CC), packets being forwarded by another radio node as forwarding intermediate nodes 211, 212, 219 (see FIG. 2). Path redundancy also results via these intermediate nodes 211 , 212 , 219 . In this regard, FIG. 2 shows an example of cooperative communication (Source: A Tutorial on Network Coding). Network-coded cooperation (Network Coded Cooperation) is also a measure to increase robustness. The forwarded messages are combined with one another in the relay nodes using methods of network coding and the combined messages are transmitted (see FIG. 3). 3 shows an example of network-coded cooperation (Network Coded Cooperation; Source: A Tutorial on Network Coding) with network-coded symbols 321, 322, 323.

If the options on a link have been exhausted via channel coding, CC and in particular NCC offer great potential, since this increases the so-called diversity order (number of propagation paths) of the overall system. It is crucial which node should combine (encode) and forward which packets.

This can be specified either pseudo-randomly (Random Linear Coding) or deterministically. In both cases, it is advantageous to know the status of the connections (link quality) between the nodes in order to adapt the coding to the network status. For this purpose, an analysis of the connection quality (link analysis) must be carried out. The term link analysis is also used synonymously below.

Knowledge of the connection quality in the network is particularly important when the transmissions in the network have to be very reliable, i.e. only have an extremely low transmission error rate and at the same time the transmission latencies have to be very low.

In the prior art, either additional test packets are transmitted or the transmitted data or management packets are used to analyze the status of the various links in a radio network. Based on the packets received, the receiving radio nodes can analyze the connection quality to the sending radio nodes. For this purpose, statistical analyzes are usually carried out on various technical parameters such as reception power, bit error rate (BER), packet error rate (PER), signal-to-noise ratio (SNR or SINR) and metrics from the channel impulse response. The results of the statistical analyzes are usually post-processed using aggregation, compression, quantization or mapping to a metric. The result is then event-driven or regularly transmitted to network management, either as a separate packet or as part of a packet to be transmitted. In any case, for the transmission of the connection quality metrics additional Transmission resources used that are no longer available for user data transmission.

WO 2014 159616 A2 shows a protocol for network coding in which so-called helper nodes use methods of random linear network coding to support data communication between different radio nodes. The configuration of the network coding and the transmission time of the packets encoded with it by the auxiliary nodes is selected on the basis of information about the status of the link quality of the various links in the network. This means that the information about the connection states must be known to the network management. However, W 02014 159616 A3 does not describe a method for measuring the connection quality in the network.

US Pat. No. 8,842,599 B2 uses relay nodes for data transmission in the downlink and uplink between a base station and end devices (user terminals). The relay nodes analyze the communication traffic that they forward between the base station and the end devices, use this to calculate information about the connection quality and forward this information to the base station. The base station processes this information and on this basis selects a relay node per group of end devices in order to apply network coding methods to the data traffic to and from this group of end devices.

US 2014 0222996 A1 shows the use of distributed monitoring in a network. Various performance parameters and metrics are collected at multiple points in the network, reflecting the current state of the connections or message flow in the network. The monitoring units transmit their analysis results to the network management. These performance parameters or metrics are analyzed with regard to their relevance in the current network status. The network management is informed about which performance parameters and metrics are currently relevant and in turn informs all monitoring units distributed in the network to only analyze the selected performance parameters. The goal is to reduce the data traffic of the monitoring units for network management by selecting the performance parameters to be analyzed.

US 2014 0036696 A1 describes how the mobile terminals in a network carry out a link analysis of their connections and forward the analysis results to a network controller. Based on this information, the Network Controller a recommendation to the terminals as to whether they should use the cellular mobile radio network or the access point of an existing WLAN network.

An apparatus according to claim 1, a method according to claim 19 and a computer program according to claim 20 are provided.

A device for determining a transmission quality in a communication network is provided. A first network unit of the communication network is set up to carry out a first data transmission in that first data to be sent by the first network unit are transmitted in such a way that a first data packet depends on the first data. A second network unit of the communication network is set up to carry out a second data transmission in that second data to be sent by the second network unit is transmitted in such a way that the second data is combined with the first data in a second data packet. The device includes a receiving unit that is designed to receive the second data transmission. Furthermore, the device includes an evaluation unit which is designed to determine a first quality of the first data transmission and/or a second quality of the second data transmission by the evaluation unit evaluating the second data packet.

Furthermore, a method for determining a transmission quality in a communication network is provided. A first network unit of the communication network carries out a first data transmission in that first data to be sent by the first network unit are transmitted in such a way that a first data packet depends on the first data. A second network unit of the communication network carries out a second data transmission in that second data to be sent by the second network unit is transmitted in such a way that the second data is combined with the first data in a second data packet. The device includes a receiving unit that receives the second data transmission. Furthermore, the device includes an evaluation unit which determines a first quality of the first data transmission and/or a second quality of the second data transmission by the evaluation unit evaluating the second data packet.

Furthermore, a computer program with a program code for carrying out the method according to an embodiment is provided.

According to embodiments, concepts are provided with which a certain radio node (eg the base station) has knowledge of the transmission quality of Can get connections in which he is not directly involved, ie is neither sending node nor receiving node, as well as connections in which he is directly involved. He obtains this knowledge solely from the analysis of the user data of received radio packets. In embodiments, no additional radio packets have to be transmitted, nor does any part of the payload in the packets have to be sacrificed to transmit link quality information. No additional network traffic is therefore required for the transmission of the connection metrics. Particular embodiments of the invention can be found in the dependent claims.

Preferred embodiments of the invention are described below with reference to the drawings. The drawings show:

1 shows a device according to an embodiment in a communication network, which also includes a first network unit, a second network unit and possibly a further, third network unit.

2 shows an example of cooperative communication. Figure 3 shows an example of network coded cooperation. 4 shows an example of a fully meshed radio network in which the base station has a connection to all radio nodes and the radio nodes are also connected to one another. 5 shows an exemplary calculation of an encoded packet based on two source packets.

Figure 6 shows an example of a full header encoded packet. 7 shows an exemplary superframe structure with network-coded cooperation. Figure 8 shows a topology of a network with one base station and three

radio node.

9 shows an example of a possible superframe structure with network-coded cooperation, the network having a base station and three radio nodes.

1 shows a device 100 according to an embodiment in a communication network, which also includes a first network unit 151 , a second network unit 152 and possibly a further, third network unit 153 .

The device 100 is a device 100 for determining a transmission quality in a communication network.

A first network unit 151 of the communication network is set up to carry out a first data transmission in that first data to be sent by the first network unit 151 is transmitted in such a way that a first data packet depends on the first data.

A second network unit 152 of the communication network is set up to carry out a second data transmission in that second data to be sent by the second network unit 152 is transmitted in such a way that the second data is combined with the first data in a second data packet.

The device 100 includes a receiving unit 110 which is designed to receive the second data transmission.

Furthermore, the device 100 includes an evaluation unit 120 which is designed to determine a first quality of the first data transmission and/or a second quality of the second data transmission by the evaluation unit 120 evaluating the second data packet.

According to one embodiment, the evaluation unit 120 can be designed, for example, to determine whether the first data transmission from the first network unit 151 to the second network unit 152 was successful by the evaluation unit 120 evaluating a header of the second data packet. In one embodiment, the evaluation unit 120 can be designed, for example, to evaluate the header of the second data packet to determine whether the header of the second data packet includes coding information for decoding the first data of the second data packet.

According to one embodiment, the evaluation unit 120 can be configured, for example, to evaluate the header of the second data packet to determine whether the header of the second data packet includes a coding coefficient that the second network unit 151 used to code the first data in the second data packet.

For example, in one embodiment, the receiving unit 110 may be configured to receive the first data transmission and the second data transmission. The evaluation unit 120 can be designed, for example, to determine a first quality of the first data transmission and/or a second quality of the second data transmission by the evaluation unit 120 evaluating the first data packet and the second data packet.

According to one embodiment, the evaluation unit 120 of the device 100 can be designed, for example, to determine the first data from the first data packet as the first determined data. The evaluation unit 120 of the device 100 can be designed, for example, to use the first determined data to determine whether the second data packet was formed using the first data. The evaluation unit 120 of the device 100 can be designed, for example, to determine that the first data transmission from the first network unit 151 to the second network unit 152 was successful if the second data packet was formed using the first data. Furthermore, the evaluation unit 120 of the device 100 can be configured, for example, to determine that the first data transmission from the first network unit 151 to the second network unit 152 was unsuccessful if the second data packet was not formed using the first data.

In one embodiment, a third network unit 153 of the communication network can be set up, for example, to carry out a third data transmission by transmitting third data to be sent by the third network unit 153 in such a way that the third data is combined with the first data and the second data in a third data packet are combined. In this case, the evaluation unit 120 of the device 100 can be designed, for example, to determine the first data from the first data packet as the first determined data. The evaluation unit 120 of the device 100 can be designed, for example, to determine the second data from the second data packet as the second determined data. Furthermore, the evaluation unit 120 of the device 100 can be designed, for example, using the first determined data and using the second determined data to determine whether the third data packet was formed using the first data and using the second data. Furthermore, the evaluation unit 120 of the device 100 can be configured, for example, to determine that the first data transmission from the first network unit 151 to the third network unit 153 was successful and that the second data transmission from the second network unit 152 to the third network unit 153 was successful is when the third data packet was formed using the first data and using the second data. The evaluation unit 120 of the device 100 can be configured, for example, to determine that the first data transmission from the first network unit 151 to the third network unit 153 and/or the second data transmission from the second network unit 152 to the third network unit 153 was unsuccessful. if the third data packet was not formed using both the first data and the second data.

According to one embodiment, the device 100 can include a transmission unit, for example, which can be set up, for example, to carry out a first further data transmission by the transmission unit to be sent first further data being transmitted in such a way that the first further data is connected to the first data and to the second Data are combined in a first further data packet. The first network unit 151 or the second network unit 152 or a further network unit 153 of the communication network can be set up, for example, to carry out a second further data transmission in that the second further data to be sent is transmitted in such a way that the second further data is combined with the first further data in a second further data packet are combined. The receiving unit 110 of the device 100 can be designed, for example, to receive the second further data transmission. The evaluation unit 120 of the device 100 can be designed, for example, to use the first additional data to determine whether the second additional data packet was formed using the first additional data. Furthermore, the evaluation unit 120 of the device 100 can be configured, for example, to determine that the first further data transmission from the device 100 to the first network unit 151 or to the second network unit 152 or to the further network unit 153 was successful if the second further Data packet was formed using the first additional data. Furthermore, the evaluation unit 120 of the device 100 can be configured, for example, to determine that the first further data transmission from the device 100 to the first network unit 151 or to the second network unit 152 or to the further network unit 153 was unsuccessful if the second further Data packet was not formed using the first additional data. In one embodiment, the device 100 can be set up, for example, to each pair of a sending network unit and a receiving network unit from a group of network units of the communication network that is the first network unit

151 and the second network unit 152 to keep a link statistic, which notes every successful data transmission from the sending network unit to the receiving network unit determined by the device 100 as a successful data transmission and/or each unsuccessful data transmission determined by the device 100 Data transmission from the sending network entity to the receiving network entity marked as an unsuccessful data transmission.

In one embodiment, the second network entity 152 can be configured, for example, to determine information about a data transmission quality from the first network entity 151 to the second network entity 152 . The second network unit 152 can be configured, for example, to transmit the information about the data transmission quality from the first network unit 151 to the second network unit 152 to the device 100 in that the second network unit 152 selects an encoding rule from a group of two or more encoding rules and the first data and/or second data and/or a combination of the first data and the second data in the second data packet is coded as a function of the coding rule and is provided with a check code. The device 100 can be configured, for example, to determine the information about the data transmission quality from the first network unit 151 to the second network unit 152 by the device 100 using the check code contained in the second data packet, the coding rule of the two or more coding rules determines which has been selected by the second network entity 152. . For example, it can be the coding rules that make up the second network unit

152 selects whether the data to be sent is Big Endian coded or Little Endian coded. The check code can be a CRC code, for example, or another error-detecting check code, or an error-correcting check code. The device can use the transmitted check code, for example, to determine whether the calculated check code and the transmitted check code match during decoding based on little endian or based on big endian, i.e. whether the data coded in the second data packet is little endian coded or are big-endian encoded.

According to one embodiment, the second network unit 152 can be set up, for example, to carry out the second data transmission by transmitting the second data to be sent by the second network unit 152 in such a way that the second data are combined with the first data as the second data packet by superposition. In one embodiment, the second network unit 152 can be set up, for example, to carry out the second data transmission by transmitting the second data to be sent by the second network unit 152 in such a way that the second data is XORed with the first data in the second data packet, or that the second data is combined with the first data by a weighted addition, or that the second data is combined with the first data by a superposition in a Galois field.

According to one embodiment, the second network unit 152 can be set up, for example, the first data, which are combined (e.g. multiplied) with a first coding coefficient, with the second data, which are combined (e.g. multiplied) with a second coding coefficient, in to combine with the second data packet.

For example, in one embodiment, the second network entity 152 may be configured to XOR the first data multiplied by a first coding coefficient with the second data multiplied by a second coding coefficient in the second data packet (an XOR operation is a superposition in the Galois field F2 ).

According to one embodiment, the communication network can be, for example, a wireless communication network, wherein the first network unit 151 can be, for example, a first wireless network unit, wherein the second network unit 152 can be, for example, a second wireless network unit, and the receiving unit 110 of the device 100 can be, for example, a receiving unit 110 for receiving wireless data transmissions.

Furthermore, in one embodiment, a base station is provided, wherein the base station may include the device 100 described above.

Also provided in one embodiment is a communication network. The communication network comprises a first network unit 151, a second network unit 152 and the device 100 described above for determining a transmission quality in a communication network. In this case, the first network unit 151 can be set up, for example, to carry out a first data transmission in that first data to be sent by the first network unit 151 are transmitted in such a way that a first data packet depends on the first data. Furthermore, the second network unit 152 can be set up, for example, to carry out a second data transmission in that second data to be sent by the second network unit 152 are transmitted in such a way that the second data are combined with the first data in a second data packet. Furthermore, the device 100 can include a receiving unit 110, for example, which can be designed, for example, to receive the second data transmission. Furthermore, the device 100 can include, for example, an evaluation unit 120, which can be designed, for example, to determine a first quality of the first data transmission and/or a second quality of the second data transmission by the evaluation unit 120 evaluating the second data packet.

According to one embodiment, the communication network can be a wireless communication network, for example. Here, the first network entity 151 may be a first wireless network entity, for example. For example, the second network entity 152 may be a second wireless network entity. Furthermore, the receiving unit 110 of the device 100 can be, for example, a receiving unit 110 for receiving wireless data transmissions.

Before specific embodiments of the invention are described in detail, general concepts on which embodiments of the invention are based will first be explained.

A network basically comprises a central base station (BS) and several radio nodes (Radio Node, _Nx ). The base station or higher-level entities are responsible for the management of the network, in particular the coordination of channel access and resource management. The network serves to transmit information between spatially distributed devices. A packet transmission from the BS to a radio node _Nx is referred to as a downlink (DL) transmission, while a transmission from a radio node _Nx to the BS is called an uplink (UL) transmission. A radio node from which useful data is to be transmitted is referred to as a source node (SN). The radio node to which a packet is transmitted is called the Destination Node (DN). 4 shows an example of a fully meshed radio network in which the base station 400 has a connection (uplink or downlink) to all radio nodes 451, 452 and the radio nodes 451, 452 are also connected to one another (side links).

For the present invention, a radio system is considered in which channel access is controlled by central resource management. Resource management is part of network management and is usually contained in the base station or in a higher-level system. Resource management decisions are distributed to the radio nodes via special messages. The modulation method used on the bit transmission layer (Engl. Physical Layer) allows resources to be divided into time (Time Division Multiple Access, TDMA) or a combination of time and frequency division, as is the case, for example, in OFDMA (Orthogonal Frequency Division Multiple Access) or Single Carrier Frequency Division Multiple Access (SC-FDMA) is implemented. In this case, the resources can be assigned to the individual transmissions in a time-frequency grid. Depending on the access method used, resource management works on the basis of time slots or time-frequency blocks. These units are hereinafter referred to synonymously as resources or resource blocks. Time-frequency blocks that follow one another in time can also be viewed as time slots.

The radio system under consideration performs isochronous cyclic communication, which is divided into frames of equal size (superframes). Real-time-critical application process data is transmitted in each superframe (IRT transmission).

Network Coded Cooperation (NCC) is described below.

NCC describes a concept in which data packets are encoded before being forwarded by a router and sent as a superposition. Several data packets (number n) are each weighted with coefficients (so-called coding coefficients) and added. For this purpose, algebra is used in finite fields and multiplication/addition in Galois fields with a size/symbol length of g bits is used. Thus, FIG. 5 shows an exemplary calculation of an encoded packet based on two source packets.

In order for a receiver to be able to decode the packet, information about the packets involved and their respective coding coefficients must be known. These coding coefficients are usually combined into a so-called coding vector. The amount of data g of a coding coefficient in bits depends on the size/dimension of the Galois field used. For Galois fields with characteristic 2, this results in 2 ⁹ coding coefficients. A coding coefficient can assume the values 0 or 1 for the minimum data volume of g=1.

If it is not known which data packets are contained and between which radio nodes they are to be transmitted, additional header information must be transmitted. This contains two logical addresses per source package, which define the data source and the data sink as well as a coding coefficient, whereby a logical address can be described by a so-called node identity (node ID/NID). For this purpose, each radio node has a unique NID.

Figure 6 shows an example of a full header encoded packet.

Specific embodiments of the invention are described below.

FIG. 7 shows an exemplary network coded cooperation (NCC) superframe structure for a network as shown in FIG. 4 (the sending node is marked in green, the receiving nodes are marked with Rx). The superframe consists of 7 slots. The messages "A" and "B" designate the user data that the base station would like to transmit to N1 or N2. The messages "a" and "b" designate the user data that N1 or N2 must transmit to the base station. In slot 0, for example, the BS sends out the message "A". The radio nodes Ni and N ₂ try to receive the packet (receive, Rx). In slot 2, the BS sends out the message "A" + "B" combined via NCC. The subsequent slots are used as shown in FIG. The superframe structure is repeated regularly and can also contain additional slots.

Exemplary embodiments are based on the fact that the radio nodes can only draw conclusions about the status or the transmission reliability of the various connections in the network by analyzing the packets received. This applies both to connections in which the respective radio node is actively involved (i.e. it is a transmitting or receiving node) and to connections in which it is not actively involved.

The method is described below using the example of evaluating the packets received from the base station. However, this does not represent a restriction. The method of evaluating the received packets can also be applied to any other node in the network.

In particular, by evaluating the contents of the packets received in slots 5 and 6, the base station obtains information about the transmission reliability on the side link Ni -> N2 and vice versa, without being directly involved in it or having to receive these side link packets. It should also be emphasized that the base station Receives information about the side links without the affected nodes Ni and N having to transmit ₂ additional monitoring packets or monitoring information to the base station.

It should be noted that the received packets and their content can be evaluated slot by slot during the course of the superframe or, alternatively, can also be evaluated at the end of a superframe.

It should also be noted that the method presented can be used for any network coding matrices, in particular for larger degrees of cooperation in which more than two messages are transmitted in an NCC-encoded packet.

A transmission of detailed quality parameters according to embodiments of the invention is presented below.

Since the procedure presented above only uses packet errors to assess the connection, it is only of limited value in situations in which packet errors occur only rarely. An improvement is therefore to analyze further parameters to assess the link quality, which already indicate an impairment of the connection before a packet loss occurs. For example, these can be parameters such as a signal-to-noise ratio (SNR) and/or a received power (RSSI) and/or a number of bit errors corrected by the error protection coding.

To assess the link quality, this information can either be used directly or variables derived from it. The selection of the parameters used and their processing must be communicated to everyone, for example through a fixed configuration or a transfer at runtime. Exemplary processing steps may be, for example, combining multiple parameters into one metric, and/or quantization, and/or thresholding, and/or equalization, and/or compression, and/or a combination thereof.

The link parameters or variables derived from them must be transmitted over the air in order to make them usable for network management. As described above, according to the current state of the art, for the transmission of this additional information, the size of the transmittable user data would have to be reduced (by transmitting additional packets or by allocating bit fields in packets to be transmitted). In order to avoid this reduction in the amount of user data that can be transmitted, the following solution methods are proposed in the present invention:

For example, embodiments may implement modification of the coding coefficients. The coding coefficients are changed when a parameter exceeds or falls below a corresponding threshold value. Alternatively, a selection can be made from a predefined set of coding coefficients in order to represent a certain value range of a parameter. For example, the bit error rate exponent can be used directly as a coding coefficient.

For example, embodiments may implement packet structure manipulation. The link analysis results can be transmitted in compressed or quantized form by specifically manipulating the NCC message or parts to be sent. Such manipulation means that the recipient, without knowledge of the manipulation, cannot correctly decode the message. Such a decoding error is detected in the receiver by a commonly used error detection code such as CRC-8, but cannot be corrected. However, if the number of possible manipulations is restricted, the recipient can try out all conceivable manipulations and withdraw them until the message can be successfully decoded and the error detection code has been checked successfully.

This method is limited by the error-detecting property of the code used. With each additional modification, the probability that an invalid packet will be recognized as valid increases.

Exemplary modifications include, but are not limited to, changing the order of bytes or bits, and/or rotating all or part of the packet by a specified number of bits; and/or a superposition of the packet with a short data word or individual bits using XOR, and/or an inversion of the packet, individual parts of it or individual bits at specific locations.

This modification can be applied to the entire transmission packet or, when using NCC, only to a partial packet.

For example, the method can be applied to the superframe structure shown in FIG. In slot 4, Ni receives the packet superposition "A"+"b" and measures the signal-to-noise ratio. If it is below a predetermined threshold value, Ni transmits the packet superposition "b"+"a" in slot 5 in big endian notation. Is that Signal-to-noise ratio below the threshold value, Ni transmits the packet superposition "b"+"a" in slot 5 in little endian notation.

The receivers interpret the received packet superposition "b"+"a" as both big endian and little endian and decode the packets. In one case the decoding fails, in the other it succeeds. Depending on which decoding was successful, the recipient learns whether the transmission in slot 5 had an SNR above or below the previously defined threshold.

In embodiments of the invention, there is no direct transmission of the packet error rate or quality parameters that can be inferred therefrom. The packet error rate is derived from information obtained from the received packets by exploiting network coding.

In embodiments, for the transmission of more detailed quality parameters of the link analysis of side links, no additional memory space in the packet has to be reserved, nor do additional packets have to be transmitted. The quality parameter information is transmitted by modifying the NCC coding or by manipulating the structure of the NCC packets.

A first detailed exemplary embodiment is presented below.

In an embodiment shown in FIG. 8, a topology of a network with a base station 400 and three radio nodes 451, 452, 453 is shown.

FIG. 9 shows an example of a possible superframe structure with network-coded cooperation, the network having a base station and three radio nodes.

A database (DB) is used to temporarily store the data from the link analysis. Each entry in the database contains the superframe number, the sending node ID, the receiving node ID and the status of packet reception (0 - successful or 1 - transmission error). These values can be summarized as a data tuple {superframe number, sending node ID, receiving node ID, status of packet reception}. For example, the successful packet transmission in superframe 12 on the link from node Ni to node N2 is described by the data tuple {12,Ni,N2,0}.

The following notations are used to simplify the explanation of the exemplary embodiment. Rx _^ _x ^,Ny =True describes the case in which the radio node Nx was able to correctly receive the packet from Ny in slot i. Equivalent describes

R _x ^ ^x _' ^N y _ _paise the case that the radio node N _x could not correctly receive the packet from N _y in slot i. {A, B} QP _i ^Ny describes that the packet sent out by radio node N _y in slot i contains the messages "A" and "B", encoded via NCC. After the superframe has expired, the base station starts evaluating the received packets and their content. By evaluating the packets received in slots 6 - 11, the base station can deduce the packet error rate on the various connections. This is described below for the superframe k, the structure of which is shown in FIG.

By filtering the link analysis database on individual links and using a sliding time window, the mean packet error rate of a link at a given point in time can be calculated. This step can be carried out for all connections listed in the database, resulting in a general overview of the connection quality in the network. This information can be made available to network management, among other things, or used in some other way. A second detailed embodiment is provided below.

Building on the scenario from the first detailed exemplary embodiment, additional information on the quality of the side links is to be transmitted to the base station in this exemplary embodiment. Here, too, the network topology shown in FIG. 8 comprising a base station and three radio nodes and the code matrix described in FIG. 9 should be used.

To determine the quality of the connections, the SNR of the side links should be collected, quantized, transmitted to the base station and incorporated into the link analysis there.

As in exemplary embodiment 1, a database (DB) is to be used for intermediate storage of the link analysis data. Here, too, each entry in the database contains the superframe number, the sending node ID, the receiving node ID and the status of packet reception (0 - successful or 1 - transmission error). In addition, the signal-to-noise ratio quantized with a two-bit resolution is also saved. The following correlation between the quantized value and the signal-to-noise ratio is used:

These values can be summarized as a data tuple {superframe number, sending node ID, receiving node ID, status of packet reception, SNR}. For example, the successful packet transmission with an SNR between 20 dB and 30 dB in superframe 12 in slot 6 on the connection from node Ni to node N ₂ is described by the data tuple {12, Ni, N ₂ , 0, 0b10}.

The radio node N ₂ is considered as an example of the communication sequence. In slots 0, 1, 2 and 3 it receives packets from the base station. This is not yet a side link. In slot 4, however, the radio node Ni transmits. The radio node N ₂ receives the transmitted message and measures the signal-to-noise ratio SNR. The measured SNR is quantized in radio node N ₂ and stored as SNR _q . The radio node N ₂ has a transmission slot in slot 5 and is to transmit the superposition "2A"+"C"+"b". In order to encode the quantized SNR into the packet to be sent, the radio node rotates the partial packet "b" by 0, 1, 2 or 3 bits to the right, depending on the value of SNR _q . The transmitted superposition is therefore "2A"+"C"+rot("b", SNR _q ).

The base station and radio nodes Ni and N ₃ receive the rotated message. The decoding method in the base station will now be described as an example. However, this does not constitute a restriction. The nodes Ni and N ₃ can in turn also carry out the decoding method described below.

The base station receives the transmitted packet superposition "2A"+"C"+rot("b", SNR _q ) and tries to decode it. The partial messages "A" and "C" are known because they were sent by the base itself. The partial message rot("b", SNR _q ) can be extracted by subtraction.

This rotated partial message is now rotated in parallel by 0, 1, 2 and 3 bits to the left in the base and each of these rotations is checked for integrity. The CRC-16 error protection code is used for this. The check will only be successful if the message was rotated to the left by SNR _q during decoding. In this way, the base station learns the quantized signal-to-noise ratio of the side link between the nodes Ni and N ₂ and can store it in the link analysis database. These steps are carried out analogously for all other nodes and side links.

An advantage of embodiments is network analysis without signaling overhead. Thanks to the concepts provided, the network management receives up-to-date information about the status of the connections in the network at any time and without delay, without requiring additional transmission resources (bit fields in packets to be transmitted or additional packets). This means that there are no restrictions on the amount of user data that can be transmitted and/or the required transmission time does not have to be extended.

Another advantage lies in the increase in reliability: Since the network management always knows the current status of the connections in the network, it can use this knowledge to optimally adapt the coding specification of the network coding used and/or the resource allocation to the individual connections to the current status of the connections use in the network. As a result, the transmission reliability on the connections can be significantly increased. Another advantage is the more efficient use of radio transmission resources: Since the network management knows the current status of the connections in the network at all times, it can use this knowledge to optimize resource scheduling, ie each connection is only assigned as many resources as are actually required will.

Another advantage is a reduction in transmission latencies: Since the transmission resources can be optimally adapted to the state of the current connection, the need for packet repetitions is reduced and the end-to-end transmission latency is reduced.

Another advantage is the suitability for radio systems with very high real-time and reliability requirements: Due to the technical properties described above and the resulting advantages, the method presented is particularly suitable for radio systems with very high requirements in terms of their real-time capability (i.e. extremely short, guaranteed transmission latencies) and reliability (i.e. extremely low transmission error probability).

In embodiments, a structure of the transmitted radio packets has only a packet header and user data, which are encoded using Network Coded Cooperation. The radio packets do not contain any separate bit fields for transmitting the connection quality. For example, a network manager can still have information about side links in the network in which the base station (or the relevant radio node to which the network manager is connected) is not actively involved. This information is used, for example, to define/adapt the coding matrix or to issue it to users (visualization) or to other technical systems (e.g. a higher-level management or the management of a neighboring communication system).

In embodiments, the structure of the packets with NCC-encoded user data is modified depending on the connection quality between the radio nodes.

A technical field of application of the presented invention is a radio system that has to meet very high requirements in terms of its high transmission reliability and that uses cooperation methods such as from the field of cooperative relaying or network coded cooperation for this purpose. Although some aspects have been described in the context of a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also constitute a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by hardware apparatus (or using a hardware Apparatus), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the essential process steps can be performed by such an apparatus.

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware, or in software, or at least partially in hardware, or at least partially in software. Implementation can be performed using a digital storage medium such as a floppy disk, a DVD, a BluRay disk, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, a hard disk or other magnetic or optical Memory are carried out on which electronically readable control signals are stored, which can interact with a programmable computer system in such a way or interaction that the respective method is carried out. Therefore, the digital storage medium can be computer-readable.

Thus, some embodiments according to the invention comprise a data carrier having electronically readable control signals capable of interacting with a programmable computer system in such a way that one of the methods described herein is carried out.

In general, embodiments of the present invention as

Computer program product to be implemented with a program code, the program code being effective to carry out one of the methods when the computer program product runs on a computer.

The program code can also be stored on a machine-readable carrier, for example. Other exemplary embodiments include the computer program for performing one of the methods described herein, the computer program being stored on a machine-readable carrier. In other words, an exemplary embodiment of the method according to the invention is therefore a computer program that has a program code for performing one of the methods described herein when the computer program runs on a computer.

A further exemplary embodiment of the method according to the invention is therefore a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded. The data carrier or digital storage medium or computer-readable medium is typically tangible and/or non-transitory.

A further exemplary embodiment of the method according to the invention is thus a data stream or a sequence of signals which represents the computer program for carrying out one of the methods described herein. For example, the data stream or sequence of signals may be configured to be transferred over a data communication link, such as the Internet.

Another embodiment includes a processing device, such as a computer or programmable logic device, configured or adapted to perform any of the methods described herein.

Another embodiment includes a computer on which the computer program for performing one of the methods described herein is installed.

A further exemplary embodiment according to the invention comprises a device or a system which is designed to transmit a computer program for carrying out at least one of the methods described herein to a recipient. The transmission can take place electronically or optically, for example. For example, the recipient may be a computer, mobile device, storage device, or similar device. The device or the system can, for example, comprise a file server for transmission of the computer program to the recipient.

In some embodiments, a programmable logic device (e.g., a field programmable gate array, an FPGA) can be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed on the part of any hardware device. This can be hardware that can be used universally, such as a computer processor (CPU), or hardware that is specific to the method, such as an ASIC.

The embodiments described above are merely illustrative of the principles of the present invention. It is understood that modifications and variations to the arrangements and details described herein will occur to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

patent claims

1. Device (100; 400) for determining a transmission quality in a communication network, wherein a first network unit (151; 451) of the communication network is set up to carry out a first data transmission by the first network unit (151; 451) sending first data are transmitted in such a way that a first data packet depends on the first data, with a second network unit (152; 452) of the communication network being set up to carry out a second data transmission in that second data to be sent by the second network unit (152; 452) are transmitted in this way that the second data are combined with the first data in a second data packet, wherein the device (100; 400) comprises a receiving unit (110) which is designed to receive the second data transmission, and wherein the device (100; 400) an evaluation unit (120) which is designed to measure a first quality of the first data transmission and/or e to determine a second quality of the second data transmission by the evaluation unit (120) evaluating the second data packet. 2. Device (100; 400) according to claim 1, wherein the evaluation unit (120) is designed to determine whether the first data transmission from the first network unit (151; 451) to the second network unit (152; 452) was successful, in that the evaluation unit (120) evaluates a header of the second data packet.

3. Device (100; 400) according to claim 2, wherein the evaluation unit (120) is formed, the header of the second

Evaluate the data packet to determine whether the header of the second data packet includes coding information for decoding the first data of the second data packet. 4. The device (100; 400) according to claim 2 or 3, wherein the evaluation unit (120) is designed to evaluate the header of the second data packet to determine whether the header of the second data packet includes a coding coefficient which the second network unit (151; 451) to encode the first data in the second data packet.

5. Device (100; 400) according to one of the preceding claims, wherein the receiving unit (110) is designed to receive the first data transmission and the second data transmission, wherein the evaluation unit (120) is designed to have a first quality of the first data transmission and/or or to determine a second quality of the second data transmission by the evaluation unit (120) evaluating the first data packet and the second data packet.

6. Device (100; 400) according to claim 5, wherein the evaluation unit (120) of the device (100; 400) is designed to determine the first data from the first data packet as the first determined data, and wherein the evaluation unit (120) of The device (100; 400) is designed to use the first determined data to determine whether the second data packet was formed using the first data, the evaluation unit (120) of the device (100; 400) being designed to determine that the first data transmission from the first network unit (151; 451) to the second network unit (152; 452) was successful if the second data packet was formed using the first data, and wherein the evaluation unit (120) of the device (100; 400 ) is adapted to determine that the first data transmission from the first network unit (151; 451) to the second network unit (152; 452) was unsuccessful if the second data packet ni cht was formed using the first data.

7. Device (100; 400) according to any one of the preceding claims, wherein a third network unit (153; 453) of the communication network is set up to carry out a third data transmission in that third data to be sent by the third network unit (153; 453) are transmitted in such a way that the third data is combined with the first data and with the second data are combined in a third data packet, wherein the evaluation unit (120) of the device (100; 400) is designed to determine the first data from the first data packet as the first determined data, and wherein the evaluation unit (120) of the device (100; 400 ) is designed to determine the second data from the second data packet as second determined data, and wherein the evaluation unit (120) of the device (100; 400) is designed to determine using the first determined data and using the second determined data whether the third data packet was formed using the first data and using the second data, the evaluation unit (120) of the device (100; 400) is adapted to determine that the first data transmission from the first network entity (151; 451) to the third network entity has been successful and that the second data transmission from the second network entity (152; 452) to the third network entity has been successful , if the third data packet was formed using the first data and using the second data, and wherein the evaluation unit (120) of the device (100; 400) is designed to determine that the first data transmission from the first network unit (151; 451) to the third network unit and/or the second data transmission from the second network unit (152; 452) to the third network unit has not been successful if the third data packet was not formed using both the first data and the second data.

Device (100; 400) according to one of the preceding claims, wherein the device (100; 400) comprises a transmission unit which is set up to carry out a first further data transmission in that the first further data to be sent by the transmission unit is transmitted in such a way that the first further data with the first data and with the second data in are combined in a first additional data packet, wherein the first network unit (151; 451) or the second network unit (152; 452) or a further network unit (153; 453) of the communication network is set up to carry out a second further data transmission by the second further data transmission to be sent Data are transmitted in such a way that the second further data are combined with the first further data in a second further data packet, the receiving unit (110) of the device (100; 400) being designed to receive the second further data transmission, the evaluation unit ( 120) of the device (100; 400) is formed using the first additional data n to determine whether the second further data packet was formed using the first further data, the evaluation unit (120) of the device (100; 400) is designed to determine that the first further data transmission from the device (100; 400) to the first network unit (151; 451) or to the second network unit (152; 452) or to the further network unit (153; 453) was successful if the second additional data packet was formed using the first additional data, and wherein the evaluation unit (120) of the device (100; 400) is designed to determine that the first additional data transmission from the device (100; 400 ) to the first network unit (151; 451) or to the second network unit (152; 452) or to the further network unit (153; 453) has not been successful if the second further data packet was not formed using the first further data.

Device (100; 400) according to any one of the preceding claims, wherein the device (100; 400) is arranged to each pair of a sending network entity and a receiving network entity from a group of Network units of the communication network which the first network unit (151;

451 ) and the second network unit (152; 452) comprises keeping link statistics which notes each successful data transmission from the sending network unit to the receiving network unit determined by the device (100; 400) as a successful data transmission and/or each unsuccessful events detected by the device (100; 400).

Data transmission from the sending network entity to the receiving network entity marked as an unsuccessful data transmission.

10. Device (100; 400) according to one of the preceding claims, wherein the second network unit (152; 452) is designed to determine information about a data transmission quality from the first network unit (151; 451) to the second network unit (152; 452). , wherein the second network unit (152; 452) is designed to transmit the information about the data transmission quality from the first network unit (151; 451) to the second network unit (152; 452) to the device (100; 400) by the second Network unit (152; 452) selects an encoding rule from a group of two or more encoding rules and encodes the first data and/or second data and/or a combination of the first data and the second data in the second data packet depending on the encoding rule and with a Check code provides, and wherein the device (100; 400) is formed, the information about the data transmission quality from the first network unit (151; 451) to the second iten network unit (152; 452) in that the device (100; 400) determines the coding rule of the two or more coding rules selected by the second network entity (152; 452) using the check code contained in the second data packet.

11. Device (100; 400) according to any one of the preceding claims, wherein the second network unit (152; 452) is set up to carry out the second data transmission by the data transmitted by the second network unit (152;

452) second data to be sent are transmitted in such a way that the second data are combined with the first data as the second data packet by superposition. 12. Device (100; 400) according to any one of the preceding claims, wherein the second network unit (152; 452) is set up to carry out the second data transmission by transmitting the second data to be sent by the second network unit (152; 452) in such a way that the second data is XORed with the first data in the second data packet, or that the second data is combined with the first data by a weighted addition, or that the second data is combined with the first data by a superposition in a Galois field .

13. Device (100; 400) according to any one of the preceding claims, wherein the second network unit (152; 452) is arranged to combine the first data, which is combined with a first coding coefficient, with the second data, which is combined with a second coding coefficient - Coefficients are combined to be combined in the second data packet.

The device (100; 400) according to claim 13, wherein the second network unit (152; 452) is arranged to multiply the first data multiplied by a first coding coefficient with the second data multiplied by a second coding coefficient are multiplied, to be XOR-linked in the second data packet.

The device (100; 400) according to any one of the preceding claims, wherein the communication network is a wireless communication network, wherein the first network entity (151; 451) is a first wireless network entity, wherein the second network entity (152; 452) is a second wireless network entity is, wherein the receiving unit (110) of the device (100; 400) is a receiving unit (110) for receiving wireless data transmissions.

16. base station of a wireless communication network, wherein the base station comprises an apparatus (100; 400) according to claim 15.

A communications network, comprising: a first network entity (151; 451), a second network entity (152; 452), and a device (100; 400) according to any one of the preceding claims to one

Determination of a transmission quality in a communication network, wherein the first network unit (151; 451) is set up to carry out a first data transmission by the first data to be sent by the first network unit (151; 451) being transmitted in such a way that a first data packet from the first data depends, wherein the second network unit (152; 452) is set up to carry out a second data transmission in that second data to be sent by the second network unit (152; 452) is transmitted in such a way that the second data is combined with the first data in a second data packet are, wherein the receiving unit (110) of the device (100; 400) is designed to receive the second data transmission, and wherein the evaluation unit (120) of the device (100; 400) is designed to determine the first quality of the first data transmission and/or to determine the second quality of the second data transmission by the evaluation unit (120) evaluating the second data packet tet.

18. Communication network according to claim 17, wherein the communication network is a wireless communication network, wherein the first network unit (151; 451) is a first wireless network unit, wherein the second network unit (152; 452) is a second wireless network unit, wherein the receiving unit (110) of the device (100; 400) is a receiving unit (110) for receiving wireless data transmissions. 19. Method for determining a transmission quality in a

Communication network, the method comprising:

Carrying out a first data transmission by a first network unit (151; 451) of the communication network by the first network unit (151; 451) to be sent first data being transmitted in such a way that a first

data packet depends on the first data,

Carrying out a second data transmission by a second network unit (152; 452) of the communication network by the second network unit (152; 452) to be sent second data being transmitted in such a way that the second

data are combined with the first data in a second data packet,

receiving the second data transmission by a receiving unit (110) of a device (100; 400), and

Determination of a first quality of the first data transmission and/or a second quality of the second data transmission by an evaluation unit (120) of the device (100; 400) by the evaluation unit (120) evaluating the second data packet.

20. A computer program with a program code for carrying out the method according to claim 19.