SYNCHRONISATIONS-BAKE

Description

[0001] Embodiments of the present invention relate to an endpoint and a base station of a communication system that communicates wirelessly in a frequency band used by a plurality of communication systems for communication. Further embodiments relate to methods for operating an endpoint and a base station of such a communication system. Some embodiments relate to a synchronization beacon (sync beacon).

[0002] From [1] the telegram splitting method is known, according to which a telegram (or data packet) is divided into a plurality of sub-data packets, which are transmitted distributed in time and optionally in frequency using a hopping pattern.

[0003] In [3] an improved range for LPWAN systems (LPWAN = Low Power Wide Area Network) that use the telegram splitting method is described.

[0004] In [4], an improved transmission security for LPWAN systems using the telegram splitting method is described.

[0005] Telegram-splitting-based communication systems utilize very broadband signals due to the hop patterns used, which are used to distribute the sub-data packets in time and frequency. New participants integrating into such a communication system have no knowledge of the hop patterns used in the communication system. Furthermore, due to quartz tolerances, newly integrated participants have no knowledge of the exact frequency position of the signals or their temporal occurrence, so a full search for the signals in time and frequency is required.

[0006] However, low-cost, battery-operated devices, such as sensor nodes, typically have a receiver whose reception bandwidth is significantly narrower than the bandwidth covered by the signals used in the telegram-splitting-based communication system due to the hopping patterns used. Furthermore, the available computing power of such low-cost, battery-operated devices is also adapted to the reception bandwidth of the receiver.

[0007] Therefore, a low-cost participant does not have the opportunity to register in such a network.

[0008] US 2002 / 080769 A1 relates to the synchronization of frequency hopping patterns of Bluetooth transceivers, where the frequency hopping pattern used for communication is derived from the master clock and the master address.

[0009] EP 2151928 A1 describes a method for fast synchronization and frequency hopping sequence detection in wireless sensor networks.

[0010] In [T ABASSAM AA ET AL: "Bluetooth Clock Recovery and Hop Sequence Synchronization Using Software Defined Radios", REGION 5 CONFERENCE, 2008 IEEE, IEEE, PISCATAWAY, NJ, USA, April 17, 2008 (2008-04-17), pages 1-5, XP031285302, ISBN: 978-1-4244-2076-6] describes a recovery of a Bluetooth clock frequency and a hop sequence synchronization using a software-based radio.

[0011] In [PETERSON BS ET AL: "Bluetooth Inquiry Time Characterization and Selection", IEEE TRANSACTIONS ON MOBILE COMPUTING, IEEE SERVICE CENTER, LOS ALAMITOS, CA, US, Vol. 5, No. 9, 1 September 2006 (2006-09-01 ), pages 1173-1187, XP001546026,ISSN: 1536-1233, DOI: 10.1109 / TMC.2006.125 [accessed 2006-07-17] describes a characterization and selection of the Bluetooth inquiry time.

[0012] In [TAQWAN THAMRIN ET AL: "The Inquiry and Page Procedure in Bluetooth Connection", SOFT COMPUTING AND PATTERN RECOGNITION, 2009. SOCPAR'09. INTERNATIONAL CONFERENCE OF, IEEE, PISCATAWAY, NJ, USA, December 4, 2009 (2009-12-04), pages 218-222, XP031593782, ISBN: 978-1-4244-5330-6] describes the inquiry and page procedure of a Bluetooth connection.

[0013] The present invention is therefore based on the object of creating a concept which enables subscribers who have only a low reception bandwidth and / or only limited computing power to log on to a communication system which uses a high signal bandwidth for communication.

[0014] This problem is solved by the independent patent claims.

[0015] Advantageous further developments can be found in the dependent patent claims.

[0016] Embodiments provide an endpoint of a communication system, wherein a control signal is transmitted in the communication system [e.g., a base station of the communication system] for coordinating the participants of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency-hopping-based [and optionally time-hopping-based] allocation of resources of a frequency band specified by a control signal hopping pattern, wherein the endpoint has a receiver, wherein a reception bandwidth of the receiver is at least a factor of 3 smaller than a bandwidth of the frequency-hopping-based [e.g., and time-hopping-based] allocation of resources of the frequency band specified by the control signal hopping pattern, wherein the endpoint is designed to receive a reference signal [e.g., synchronization signal], wherein the reference signal has information about the control signal, wherein the endpoint is designed,to receive the control signal based on the information about the control signal, wherein the information about the control signal that the reference signal comprises comprises information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the reference signal is transmitted in a predetermined frequency range of the frequency band, wherein the reference signal comprises a plurality of partial reference data packets that contain the information about the control signal, wherein the reference signal is transmitted according to a reference hopping pattern, wherein the reference hopping pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the predetermined frequency range, wherein the endpoint is configured to receive the reference signal according to the reference hopping pattern,to obtain at least a portion of the plurality of partial reference data packets sufficient for decoding.

[0017] In embodiments, a reception bandwidth of the receiver may be at least a factor of 5 smaller than a bandwidth of the frequency hopping-based occupancy of resources of the frequency band specified by the control signal hopping pattern.

[0018] In embodiments, a reception bandwidth of the receiver may be at least a factor of 10 smaller than a bandwidth of the frequency hopping-based allocation of resources of the frequency band specified by the control signal hopping pattern

[0019] In embodiments, the endpoint may be configured to switch a receiving frequency of the receiver of the endpoint based on the control signal hopping pattern to the respective resources of the frequency band specified by the control signal hopping pattern [e.g., defined by time slots and frequency channels into which the frequency band is divided] to receive the control signal.

[0020] In embodiments, the information about the control signal that the reference signal comprises may comprise information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system [e.g., base station] to transmit the control signal.

[0021] For example, the information about the control signal jump pattern may be the control signal jump pattern itself.

[0022] For example, the control signal jump pattern can be derived from the information about the control signal jump pattern.

[0023] For example, the information about the control signal jump pattern may be a control signal jump pattern index that uniquely identifies the control signal jump pattern from a set of control signal jump patterns to which different control signal jump pattern indices are assigned.

[0024] For example, the resources of the frequency band that can be used by the communication system to transmit the control signal can be specified by a channel access pattern, wherein the control signal is transmitted, for example, in accordance with the control signal hopping pattern (=relative channel access pattern) in, for example, a subset of the resources specified by the channel access pattern.

[0025] For example, the information about the resources available to the communication system for transmitting the control signal can describe a state (e.g., PAN counter) of a number sequence generator for generating a number sequence or a number in a number sequence, where the number sequence determines the channel access pattern. Furthermore, the information about the resources available to the communication system for transmitting the control signal can describe individual information of the communication system (e.g., PAN ID).

[0026] In embodiments, the information about the control signal may include information about a time and frequency position of the control signal with respect to the reference signal.

[0027] In embodiments, the endpoint may be configured to synchronize a timer and / or frequency generator of the endpoint to the reference signal.

[0028] In embodiments, the reference signal and the control signal may be synchronized with each other in time [e.g., have a defined time interval].

[0029] In embodiments, the receiver of the endpoint may have a receive bandwidth corresponding to a bandwidth of two to ten immediately adjacent frequency channels into which the frequency band is divided.

[0030] For example, a reception bandwidth of the endpoint receiver may be as large as a bandwidth of two to four immediately adjacent frequency channels, e.g., so that the receiver can receive the two to four frequency channels simultaneously.

[0031] In embodiments, the receiver of the endpoint may have a receive bandwidth corresponding to a bandwidth of two to four immediately adjacent frequency channels into which the frequency band is divided.

[0032] In embodiments, the endpoint receiver may have a receive bandwidth of 250 kHz or less.

[0033] In embodiments, the endpoint receiver may have a receive bandwidth of 100 kHz or less.

[0034] In embodiments, the endpoint may be battery powered.

[0035] In embodiments, the specified frequency range can be fixed and the end point can be known.

[0036] In embodiments, the predetermined frequency range may comprise at least one frequency channel of the frequency band.

[0037] In embodiments, the predetermined frequency range may comprise a plurality of frequency channels, wherein at least two frequency channels of the plurality of frequency channels are at most so far apart that the two frequency channels are within a frequency bandwidth that corresponds to the reception bandwidth of the receiver [e.g. wherein at least two frequency channels of the plurality of frequency channels are immediately adjacent frequency channels of the frequency band].

[0038] For example, the reference signal may comprise three sub-data packets, wherein the endpoint may be configured to receive at least two of the sub-data packets to decode the content, and wherein the endpoint may be configured to precisely synchronize in time based on the arrangement of the two sub-data packets.

[0039] In embodiments, a reference data packet [e.g. synchronization data packet] with the information about the control signal can be divided into the plurality of partial reference data packets, so that each of the partial reference data packets has only a part of the reference data packet, wherein the plurality of partial reference data packets can be channel-coded, so that only a subset of the plurality of partial reference data packets is required for successful decoding of the reference data packet, wherein the endpoint can be configured to receive and decode at least a part of the plurality of partial reference data packets in order to obtain the reference data packet with the information about the control signal.

[0040] In embodiments, the predetermined frequency range may have one or more sub-frequency ranges, wherein the predetermined frequency range may be wider than the reception bandwidth of the receiver of the endpoint, wherein, in accordance with the reference hopping pattern, at least as many of the plurality of partial reference data packets are transmitted per sub-frequency range within the predetermined frequency range as are required for the successful decoding of the reference data packet, wherein each of the one or more sub-frequency ranges corresponds to the reception bandwidth of the receiver of the endpoint.

[0041] In embodiments, the reference signal can be transmitted at predetermined intervals [e.g. periodically], wherein the reference signal is transmitted alternately in at least two predetermined sub-frequency ranges of the predetermined frequency range known to the end point.

[0042] In embodiments, the at least two predetermined sub-frequency ranges can be separated from each other in frequency to such an extent that accidental synchronization to the other predetermined sub-frequency range caused by a frequency offset is not possible.

[0043] In embodiments, the reference signal can be transmitted according to a reference hop pattern, wherein the reference hop pattern indicates a frequency- and / or time-hop-based allocation of resources of the predetermined frequency range, wherein the resources are defined by frequency channels, wherein at least two adjacent frequency channels of the frequency channels allocated according to the reference hop pattern are separated from each other in terms of frequency to such an extent that they do not overlap even with a frequency offset [e.g., by a quartz crystal].

[0044] In embodiments, the reference signal may be transmitted according to a reference hop pattern, wherein the reference hop pattern indicates a frequency- and / or time-hop-based allocation of resources of the predetermined frequency range, wherein an allocation of resources indicated by the reference hop pattern does not have repeating identical distances between the resources in time and / or frequency.

[0045] In embodiments, the reference signal may comprise a plurality of partial reference data packets, wherein at least two of the plurality of partial reference data packets comprise information known to the endpoint [e.g., an ID of the communication system], wherein the endpoint may be configured to perform synchronization based on the known information.

[0046] In embodiments, at least two of the plurality of partial reference data packets may comprise partial synchronization sequences known to the endpoint, wherein the endpoint may be configured to perform synchronization based on the partial synchronization sequences and the known information.

[0047] In embodiments, within the at least two of the plurality of partial reference data packets, the respective partial synchronization sequence and the respective known information may form virtual synchronization sequences, wherein the endpoint may be configured to perform the synchronization based on the virtual synchronization sequences of the at least two [or all] of the plurality of partial reference data packets.

[0048] In embodiments, within the at least two of the plurality of partial reference data packets, the respective partial synchronization sequence and the respective known information may have a predetermined distance from one another [e.g., immediately follow one another or are spaced apart from one another by a predetermined number of symbols].

[0049] In embodiments, the communication system may communicate wirelessly in a frequency band used by a plurality of communication systems for communication [e.g., wherein the communication systems are uncoordinated with each other].

[0050] In embodiments, the control signal and / or the reference signal may comprise information about a network-specific channel access pattern, wherein the network-specific channel access pattern indicates a frequency- and / or time-hopping-based allocation of resources of the frequency band that can be used for the communication of the communication system.

[0051] In embodiments, the control signal hop pattern (1) can be fixedly defined and be the same for each transmission of the control signal (e.g. beacon) (e.g. the control signal hop pattern is used from a stock) or the control signal hop pattern can (2) be part of the channel access pattern and thus change each time the control signal (e.g. beacon) is transmitted. In the first case, an endpoint can receive the control signal hop pattern without knowledge of the state (e.g. counter reading) of the number sequence generator for generating a number sequence that determines the channel access pattern, and the individual information of the communication system (e.g. ID). The ID and the current counter reading for the following channel access pattern are transmitted in the control signal hop pattern. In the second case, the subscriber receiving the control signal already has knowledge of the ID and the counter reading.counter), since the channel access pattern is calculated from these parameters. In the first case, the reference signal (e.g., synchronization beacon) does not need to contain any information about the ID and counter value; in the second case, it does.

[0052] In embodiments, the control signal hop pattern can be a fixed hop pattern. In this case, the control signal (e.g., data beacon) transmits the ID (e.g., PAN ID) and the counter reading to signal the channel access pattern for the subsequent data transmission. In embodiments, the control signal hop pattern can be part of the channel access pattern. In this case, the reference signal contains the ID (e.g., PAN ID) and the counter reading. Further data for coordinating or controlling participants (e.g., downlink times for specific nodes) is transmitted in the control signal (e.g., data beacon).

[0053] In embodiments, the information about the control signal may comprise [e.g. be] information about a network-specific channel access pattern, wherein the network-specific channel access pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the frequency band usable for the communication of the communication system, wherein the control signal hopping pattern is a relative channel access pattern, wherein the control signal is transmitted according to the relative channel access pattern in at least a subset of the resources of the frequency band specified by the channel access pattern.

[0054] In embodiments, the control signal may be transmitted according to the relative channel access pattern in the first resources of the resources of the frequency band specified by the channel access pattern.

[0055] In embodiments, the endpoint may be configured to divide a data packet [e.g., the physical layer in the OSI model] to be transmitted into a plurality of sub-data packets, each of which is shorter than the data packet, and to transmit a data signal comprising the plurality of sub-data packets according to a relative channel access pattern in a subset of the usable frequency- and / or time-hopping-based allocation of resources of the frequency band specified by the network-specific channel access pattern.

[0056] Further embodiments provide a base station of a communication system, wherein the base station is designed to transmit a control signal [e.g. beacon signal] for coordinating the subscribers of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency hopping-based [e.g. and time hopping-based] occupancy of resources of a frequency band specified by a control signal hopping pattern, wherein the base station is designed to transmit a reference signal [e.g. synchronization signal], wherein the reference signal has information about the control signal, wherein the predetermined frequency range is at least a factor of 3 smaller [e.g. narrower] than a frequency range of the frequency band in which the control signal is transmitted in a distributed manner according to the control hopping pattern, wherein the information about the control signal which the reference signal has,information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the base station is designed to provide the reference signal with a plurality of partial reference data packets that contain the information about the control signal, wherein the base station is designed to transmit the reference signal according to a reference signal hopping pattern, wherein the reference signal hopping pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the predetermined frequency range, wherein the base station is designed to divide a reference data packet with the information about the control signal into the plurality of partial reference data packets, so that each of the partial reference data packets has only a part of the reference data packet, wherein the plurality of partial reference data packets are channel-coded,so that only a subset of the plurality of partial reference data packets is required to successfully decode the reference data packet.

[0057] In embodiments, the predetermined frequency range may be adapted to a reception bandwidth of a receiver of the endpoint, wherein the frequency range of the frequency band in which the control signal is transmitted distributed according to the control signal hopping pattern may be larger by a factor of 3 than the predetermined frequency range.

[0058] In embodiments, the predetermined frequency range may comprise at least one frequency channel of the frequency band.

[0059] In embodiments, the predetermined frequency range may comprise a plurality of frequency channels, wherein at least two frequency channels of the plurality of frequency channels are at most so far apart that the two frequency channels are within a frequency bandwidth that corresponds to a reception bandwidth of a receiver of an endpoint of the communication system [e.g. wherein at least two frequency channels of the plurality of frequency channels are immediately adjacent frequency channels of the frequency band].

[0060] In embodiments, the information about the control signal that the reference signal comprises may comprise information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system [e.g., base station] to transmit the control signal.

[0061] For example, the information about the control signal jump pattern may be the control signal jump pattern itself.

[0062] For example, the control signal jump pattern can be derived from the information about the control signal jump pattern.

[0063] For example, the information about the control signal jump pattern may be a control signal jump pattern index that uniquely identifies the control signal jump pattern from a set of control signal jump patterns to which different control signal jump pattern indices are assigned.

[0064] For example, the resources of the frequency band that can be used by the communication system to transmit the control signal can be specified by a channel access pattern, wherein the control signal is transmitted, for example, in accordance with the control signal hopping pattern (=relative channel access pattern) in, for example, a subset of the resources specified by the channel access pattern.

[0065] For example, the information about the resources available to the communication system for transmitting the control signal can describe a state (e.g., PAN counter) of a number sequence generator for generating a number sequence or a number in a number sequence, where the number sequence determines the channel access pattern. Furthermore, the information about the resources available to the communication system for transmitting the control signal can describe individual information of the communication system (e.g., PAN ID).

[0066] In embodiments, the information about the control signal may include information about a time and frequency position of the control signal with respect to the reference signal.

[0067] In embodiments, the base station may be configured to transmit the reference signal and the control signal synchronized in time with each other [e.g., with a defined time interval between each other].

[0068] In embodiments, the predetermined frequency range may comprise one or more sub-frequency ranges, wherein the predetermined frequency range is wider than a reception bandwidth of a receiver of an endpoint of the communication system, wherein the base station is configured to transmit, in accordance with the reference signal hopping pattern per sub-frequency range within the predetermined frequency range, at least as many of the plurality of sub-reference data packets as are required for the successful decoding of the reference data packet, wherein each of the one or more sub-frequency ranges corresponds to the reception bandwidth of the receiver of the endpoint.

[0069] In embodiments, the base station may be configured to transmit the reference signal at predetermined intervals [e.g., periodically], wherein the base station may be configured to transmit the reference signal alternately in at least two predetermined sub-frequency ranges of the predetermined frequency range known to the endpoint.

[0070] In embodiments, the at least two predetermined sub-frequency ranges can be separated from each other in frequency to such an extent that accidental synchronization to the other predetermined sub-frequency range caused by a frequency offset is not possible.

[0071] In embodiments, the reference signal can be transmitted according to a reference hop pattern, wherein the reference hop pattern indicates a frequency- and / or time-hop-based allocation of resources of the predetermined frequency range, wherein the resources are defined by frequency channels, wherein at least two adjacent frequency channels of the frequency channels allocated according to the reference hop pattern are separated from each other in terms of frequency to such an extent that they do not overlap even with a frequency offset [e.g. by a quartz crystal].

[0072] In embodiments, the reference signal may be transmitted according to a reference hop pattern, wherein the reference hop pattern indicates a frequency- and / or time-hop-based occupancy of resources of the predetermined frequency range, wherein an occupancy of resources indicated by a reference hop pattern does not have repeating identical distances between the resources in time and / or frequency.

[0073] In embodiments, the base station may be configured to transmit the reference signal at predetermined intervals [e.g., periodically], wherein the base station may be configured to dynamically adapt an interval between at least two consecutive transmissions of the reference signal to a number of newly registered endpoints, or wherein the base station is configured to additionally transmit the reference signal in response to an external event [e.g., between two scheduled transmissions of the reference signal].

[0074] In embodiments, the base station may be configured to provide the reference signal with a plurality of partial reference data packets, wherein the base station may be configured to dynamically adapt a number of the partial reference data packets with which the reference signal is provided to a number of newly registered endpoints.

[0075] In embodiments, the base station may be configured to distribute the plurality of partial reference data packets to different frequency channels of the predetermined frequency range according to a reference signal hopping pattern, wherein the base station may be configured to dynamically adapt a number of different frequency channels of the predetermined frequency range to which the plurality of partial reference data packets are distributed to the number of newly registered endpoints.

[0076] In embodiments, the base station may be configured to repeatedly transmit the reference signal, wherein the base station may be configured to provide the reference signal with a plurality of partial reference data packets, wherein the base station may be configured to temporally interleave the plurality of partial reference data packets of at least two transmissions of the reference signal according to respective reference signal hopping patterns.

[0077] In embodiments, the respective reference signal jump patterns may be time and frequency shifted versions of each other.

[0078] In embodiments, a time interval between the plurality of partial reference data packets of the respective reference signal may correspond to the number of repetitions.

[0079] In embodiments, the base station may be configured to provide the reference signal with a plurality of partial reference data packets, wherein at least two of the plurality of partial reference data packets comprise data known to the endpoint [e.g., an ID of the communication system].

[0080] In embodiments, the at least two of the plurality of partial reference data packets may include partial synchronization sequences known to the endpoint.

[0081] In embodiments, within the at least two of the plurality of partial reference data packets, the respective partial synchronization sequence and the respective known data may form virtual synchronization sequences.

[0082] In embodiments, within the at least two of the plurality of partial reference data packets, the respective partial synchronization sequence and the respective known data may have a predetermined distance from one another [e.g., immediately follow one another or are spaced apart by a predetermined number of symbols].

[0083] In embodiments, the base station may be configured to interleave data known to the endpoint into at least two of the plurality of partial reference data packets such that each of the at least two of the plurality of partial reference data packets includes a portion of the known data.

[0084] In embodiments, the base station may be configured to provide the reference signal with a plurality of partial reference data packets, wherein the base station may be configured to adapt a number of the partial reference data packets to an error protection code used for the control signal.

[0085] In embodiments, the base station may be configured to provide the reference signal and the control signal with the same error protection code or with error protection codes of comparable performance.

[0086] In embodiments, the plurality of partial reference data packets may be symbolically identical.

[0087] In embodiments, the communication system may communicate wirelessly in a frequency band used by a plurality of communication systems for communication [e.g., wherein the communication systems are uncoordinated with each other].

[0088] In embodiments, the control signal or the reference signal may comprise information about a network-specific channel access pattern, wherein the network-specific channel access pattern indicates a frequency- and / or time-hopping-based allocation of resources of the frequency band usable for the communication of the communication system.

[0089] In embodiments, the communication system can communicate based on a network-specific channel access pattern, wherein the network-specific channel access pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the frequency band usable for the communication of the communication system, wherein the control signal hopping pattern is a relative channel access pattern, wherein the base station is configured to transmit the control signal according to the relative channel access pattern in at least a subset of the resources of the frequency band specified by the channel access pattern.

[0090] In embodiments, the base station may be configured to transmit the control signal according to the relative channel access pattern in the first resources of the resources of the frequency band specified by the channel access pattern.

[0091] In embodiments, the frequency range of the frequency band in which the control signal is transmitted distributed according to the control signal hopping pattern can be larger by a factor of 5 than the predetermined frequency range.

[0092] In embodiments, the frequency range of the frequency band in which the control signal is transmitted distributed according to the control signal hopping pattern can be larger by a factor of 10 than the predetermined frequency range.

[0093] Further embodiments provide a communication system having an endpoint according to any of the embodiments described herein and a base station according to any of the embodiments described herein.

[0094] Further embodiments provide a method for operating an endpoint of a communication system, wherein a control signal is transmitted in the communication system [e.g., a base station of the communication system] for coordinating the participants of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency-hopping-based [e.g., and time-hopping-based] allocation of resources of the frequency band specified by a control signal hopping pattern, wherein the endpoint has a receiver, wherein a reception bandwidth of the receiver is at least a factor of 3 smaller than a bandwidth of the frequency-hopping-based [e.g., and time-hopping-based] allocation of resources of the frequency band specified by the control signal hopping pattern. The method comprises a step of receiving a reference signal [e.g., synchronization signal],wherein the reference signal comprises information about the control signal. Furthermore, the method comprises a step of receiving the control signal based on the information about the control signal, wherein the information about the control signal that the reference signal comprises comprises information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal. The reference signal is transmitted in a predetermined frequency range of the frequency band. The reference signal comprises a plurality of partial reference data packets that contain the information about the control signal. The reference signal is transmitted according to a reference hopping pattern, the reference hopping pattern indicating a frequency- and / or time-hopping-based allocation of resources of the predetermined frequency range.wherein the reference signal is received according to the reference hop pattern in order to obtain at least a portion of the plurality of partial reference data packets sufficient for decoding.

[0095] Further embodiments provide a method for operating a base station of a communication system. The method comprises a step of transmitting a control signal for coordinating the subscribers of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency-hopping-based [e.g., and time-hopping-based] allocation of resources of the frequency band specified by a control signal hopping pattern. Furthermore, the method comprises a step of transmitting a reference signal [e.g., a synchronization signal], wherein the reference signal comprises information about the control signal, wherein the predetermined frequency range is at least a factor of 3 smaller [e.g., narrower] than a frequency range of the frequency band in which the control signal is transmitted in a distributed manner according to the control hopping pattern, wherein the information about the control signal, which the reference signal comprises,has information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the reference signal is provided with a plurality of partial reference data packets that contain the information about the control signal, wherein the reference signal is transmitted according to a reference signal hopping pattern, wherein the reference signal hopping pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the predetermined frequency range, wherein a reference data packet with the information about the control signal is divided among the plurality of partial reference data packets, so that each of the partial reference data packets has only a part of the reference data packet, wherein the plurality of partial reference data packets are channel-coded,so that only a subset of the plurality of partial reference data packets is required to successfully decode the reference data packet.

[0096] In embodiments, a reference signal or synchronization signal (e.g. with so-called sync (partial) data packets) can be inserted before the control signal (beacon), which can be used by newly registered participants for initial synchronization in time and / or frequency.

[0097] Embodiments of the present invention are described in more detail with reference to the accompanying figures. They show: Fig. 1 is a schematic block diagram of a communication arrangement with a first communication system, Fig. 2 is a schematic block diagram of a communication arrangement of two mutually uncoordinated networks, each with a base station and four associated terminals, Fig. 3 is a diagram showing a division of the frequency band into resources and a frequency- and time-hopping-based allocation of the resources of the frequency band defined by two different channel access patterns, Fig. 4 is a schematic block diagram of a communication system with a base station and a plurality of endpoints, Fig. 5 is a schematic block diagram of a controller for generating a channel access pattern, Fig. 6 is a schematic block diagram of a controller for generating a channel access pattern, Fig. 7 is a schematic block diagram of a section of the controller, Fig.8 shows a diagram showing a histogram based on a Monte Carlo simulation over the variable Δfi. Fig. 9 shows a diagram showing a frequency- and time-hopping-based occupancy of the resources of the frequency band defined by a channel access pattern, as well as a projection of the channel access pattern onto a time axis. Fig. 10 shows a diagram showing resource elements of a channel access pattern projected onto a time axis, resulting in unused time slots. Fig. 11 shows a diagram showing resource elements of a channel access pattern with an activity rate A=1 / 4 projected onto a time axis. Fig. 12 shows a diagram showing resource elements of a channel access pattern with an activity rate A=1 / 4 and a predetermined minimum distance between successive time slots of the channel access pattern, projected onto a time axis. Fig. 13 shows a temporal division of a channel access pattern 110 into areas of different activity rates A1, A2, and A3.14 in a diagram, a frequency and time-hopping based allocation of the resources of the frequency band defined by a channel access pattern, wherein the channel access pattern additionally has resources that can be activated as needed, Fig. 15 in a diagram, a frequency and time-hopping based allocation of the resources of the frequency band defined by a channel access pattern, wherein a frequency range of the frequency band that is regularly subject to greater interference is not occupied by the channel access pattern, Fig. 16 in a diagram, a frequency and time-hopping based allocation of the resources of the frequency band defined by a channel access pattern, wherein resources are bundled in the frequency range, Fig. 17 a schematic block diagram of a communication system with a base station and two endpoints, Fig.18in a diagram, a frequency- and time-hopping-based usable occupancy of resources of the frequency band specified by a network-specific channel access pattern, an occupancy of resources to be used for transmission specified by a relative channel access pattern from the usable occupancy of resources of the network-specific channel access pattern, as well as projections of the channel access patterns on time axes before and after the removal of unused resources (e.g. time slots), Fig.19in a diagram, a frequency- and time-hopping-based usable occupancy of resources of the frequency band bundled in the frequency domain, specified by a network-specific channel access pattern, an occupancy of resources to be used for transmission from the usable occupancy of resources of the network-specific channel access pattern, specified by a relative channel access pattern, as well as projections of the channel access patterns on time axes before and after removal of unused resources (e.g. time slots), Fig.20 in a diagram, a frequency- and time-hopping-based usable occupancy of resources of the frequency band bundled in the frequency domain, specified by a network-specific channel access pattern, an occupancy of resources to be used for transmission from the usable occupancy of resources of the network-specific channel access pattern, specified by a relative channel access pattern, an occupancy of resources to be used for transmission from the usable occupancy of resources of the network-specific channel access pattern, as well as projections of the channel access patterns on time axes before and after removal of unused resources (e.g. time slots), Fig. 21 in a diagram, a projection of a network-specific channel access pattern and a relative channel access pattern on the time axis after removal of unused resources (e.g.Frequency channels and time slots), wherein the relative channel access pattern in the frequency direction occupies several of the resources available in the frequency direction for at least some of the time hops, Fig. 22 in a diagram, a frequency- and time-hop-based usable occupancy of resources of the frequency band bundled into blocks (or clusters) in the frequency domain, specified by a network-specific channel access pattern, wherein different symbol rates and / or different numbers of symbols are assigned to different parts of the block of contiguous resources, Fig. 23 in a diagram, a projection of a network-specific channel access pattern and a relative channel access pattern with D resources onto the time axis after removing unused resources (frequency channels and time slots), Fig. 24 in a table, a resource calculation for various exemplary use cases, Fig.25 in a diagram showing simulation results of the packet error rate for different channel access pattern lengths M as a function of the number of simultaneously active terminals with 360 available resource elements, Fig. 26 in a diagram showing simulation results of the packet error rate for different channel access pattern lengths M as a function of the number of simultaneously active terminals with 60 available resource elements, Fig. 27 in a diagram showing resources of a channel access pattern projected onto a time axis, wherein resources of the channel access pattern are grouped into clusters of the same length L (e.g. L=4), wherein the relative channel access pattern indicates an occupancy of one resource per cluster, Fig. 28 a schematic block diagram of a communication system with a base station and an endpoint, according to an embodiment of the present invention, Fig.29 shows a diagram illustrating the allocation of resources in the frequency band during the transmission of the reference signal with a reference data packet, as well as the allocation of resources in the frequency band, as specified by the control signal hopping pattern, during the transmission of the control signal with the plurality of partial control data packets, according to an exemplary embodiment of the present invention. Fig. 30 shows a diagram illustrating the allocation of resources in the predetermined frequency range of the frequency band, as defined by a reference signal hopping pattern, during the transmission of the reference signal with a plurality of partial reference data packets, as well as the allocation of resources in the frequency band, as specified by a control signal hopping pattern, during the transmission of the control signal with the plurality of partial control data packets, according to an exemplary embodiment of the present invention.31 in a diagram, an occupancy of resources of the frequency band defined by a reference signal hopping pattern during the repeated transmission of the reference signal with the plurality of partial reference data packets in different partial frequency ranges of the predetermined frequency range, as well as an occupancy of resources of the frequency band specified by a control signal hopping pattern during the repeated (periodic) transmission of the control signal with the plurality of partial control data packets, according to an embodiment of the present invention, Fig.32 shows, in a diagram, the allocation of resources of the predetermined frequency range of the frequency band during the multiple transmission of the reference signal, indicated by reference signal hopping patterns, so that the plurality of partial reference data packets of the multiple transmission of the reference signal are temporally interleaved, as well as an allocation of resources of the frequency band during the transmission of the control signal with the plurality of partial control data packets, defined by a control signal hopping pattern, according to an embodiment of the present invention. Fig. 33 shows a schematic view of one of the plurality of partial reference data packets, according to an embodiment of the present invention. Fig. 34 shows a schematic view of the coding and division of the data of a reference data packet into a plurality of partial reference data packets, according to an embodiment of the present invention.35 shows a schematic view of the division of coded data into a plurality of partial reference data packets, according to an embodiment of the present invention, Fig. 36 shows a flowchart of a method for operating an endpoint of a communication system, according to an embodiment of the present invention, and Fig. 37 shows a flowchart of a method for operating a base station of a communication system, according to an embodiment of the present invention.

[0098] In the following description of the embodiments of the present invention, identical or equivalent elements in the figures are provided with the same reference numerals so that their description is interchangeable.

[0099] It is assumed below that within each network there is a coordinating entity (hereinafter referred to as "base station") as well as non-coordinating participants (hereinafter referred to as "terminals").

[0100] For the operation of low-power wide area networks (LPWANs), the transmission of messages using telegram splitting has proven particularly advantageous. The basic principles of this transmission principle are illustrated by examples in [1], [3], [4]. A message (data packet) is divided into numerous sub-data packets and transmitted in a distributed manner across different time / frequency resources. The sequence of transmission of the sub-data packets in time and frequency is referred to as the channel access pattern or hopping pattern.

[0101] In channel access procedures, for example, in LPWAN networks, "contention-based access" is often used. In this case, end devices do not have exclusively assigned resources at their disposal; instead, multiple end devices access a shared set of radio resources on their own initiative. This can lead to access conflicts, i.e., the simultaneous use of radio resources by two or more users. To minimize the impact of such access conflicts, the end devices have access to a pool of different channel access patterns (hop patterns).

[0102] These channel access patterns (or parameters from which the channel access pattern can be derived) are typically transmitted by the coordinating instance to the participants of the network in a beacon (see Section A).

[0103] In order to minimize the interference immunity of these networks, each network usually uses a different channel access pattern, which is also time-dependent.

[0104] New participants who want to join a network initially have no information about the channel access pattern in use or the current state of the channel access pattern. Furthermore, due to quartz tolerances, they have no knowledge of the exact frequency of the signal or the timing of the beacon. They must therefore perform a full search (in time and frequency) for the beacon.

[0105] Networks that use a beacon typically occupy a relatively high signal bandwidth of several tens of kHz. Since, with typical quartz tolerances of 20 ppm, the signal can be shifted by a few tens of kHz for a 1 GHz carrier, a large portion of the signal is still receivable at the receiver, even if the frequencies are shifted accordingly. This makes it easier to compensate for the frequency offset, thus requiring only one beacon search over time.

[0106] However, if a narrowband system with a low signal bandwidth is used, both the time and the frequency are unknown, since the signal bandwidth is smaller, and for high reception sensitivity, the corresponding filter in front of the receiver is designed to be narrower than the expected frequency offset. To perform a full scan, the participant must be able to scan the spectrum with a bandwidth at least equal to the signal bandwidth plus the frequency offsets.

[0107] In addition, the participant must be able to process the corresponding sampled signal so quickly that, during the time the data is processed, the frequency and time offsets caused by the quartz tolerances have not yet had such a strong effect that a new synchronization is necessary.

[0108] If the frequency or channel access pattern for the next beacons is transmitted in a beacon, the data processing must be completed accordingly before this information loses its validity.

[0109] Networks that use the telegram splitting method only require a small bandwidth for the individual transmission of a partial data packet. However, since the reception of several partial subpackets is necessary for synchronization, and these are distributed over a large bandwidth using frequency hopping to reduce susceptibility to interference, it is still necessary to consider a large frequency range for the initial synchronization for synchronization with a telegram splitting signal.

[0110] In small (often battery-powered) (low-cost) devices, such high-speed data processing is not available, and the necessary reception bandwidth cannot usually be provided. Thus, a (low-cost) device does not have the option to log on to a network, even if, as described in Section B, it can communicate without problems after successful registration.

[0111] This is where embodiments of the present invention come into play, in which a reference signal is transmitted before the control signal (e.g. beacon signal), which can be used by newly registered subscribers for initial synchronization in time and frequency.

[0112] Before embodiments of the present invention are described in Section C, which enable an endpoint to log on to a communication system which uses signals for transmitting data which have a significantly greater bandwidth than a receiver of the endpoint can process simultaneously, Section A first explains how communication systems which communicate in the same frequency band can be separated from one another by different channel access patterns, and then Section B explains how one or more subscribers of a communication system can access a selection of the resources released for the communication system by the network-specific channel access pattern using a relative channel access pattern. A. Network-specific channel access patterns

[0113] The examples following in this Section A and its subsections are not in accordance with the invention and are for illustrative purposes only.

[0114] Fig. 1 shows a schematic block diagram of a communication arrangement 100 with a first communication system 102_1, according to an example.

[0115] The first communication system 102_1 may include a base station 104_1 and one or more endpoints 106_1-106_n, where n is a natural number greater than or equal to one. In the Fig. 1 In the example shown, the first communication system 102_1 has four endpoints 106_1-106_4 for illustrative purposes, but the first communication system 104_1 may equally well have 1, 10, 100, 1,000, 10,000, or even 100,000 endpoints.

[0116] The first communication system 102_1 can be configured to communicate wirelessly in a frequency band (e.g., a license-free and / or authorization-free frequency band, e.g., ISM band) that is used by a plurality of communication systems for communication. The frequency band can have a significantly larger bandwidth (e.g., at least a factor of two) than the reception filters of the subscribers of the first communication system 102_1.

[0117] Within range of the first communication system 102_1, as shown in Fig. 1 is indicated - for example, a second communication system 102_2 and a third communication system 102_3, whereby these three communication systems 102_1, 102_2 and 102_3 can use the same frequency band for wireless communication.

[0118] The first communication system 102_1 can be designed to use different frequencies or frequency channels of the frequency band (e.g. into which the frequency band is divided) in sections (e.g. time slot by time) for communication based on a channel access pattern, regardless of whether they are used by another communication system (e.g. the second communication system 102_2 and / or the third communication system 102_3), wherein the channel access pattern differs from another channel access pattern based on which at least one other communication system of the plurality of other communication systems (e.g. the second communication system 102_2) accesses the frequency band.

[0119] In such a communication arrangement 100 as shown in Fig. 1As shown, the signals of mutually uncoordinated communication systems (e.g. the first communication system 102_1 and the second communication system 102_2) can thus be separated from one another by different channel access patterns, so that mutual disturbance by interference is avoided or minimized.

[0120] For example, subscribers of the first communication system 102_1, such as a base station 104_1 and a plurality of endpoints 106_1-106_4, can communicate wirelessly with each other based on a first channel access pattern (e.g., which specifies a frequency-hopping-based allocation (e.g., of resources) of the frequency band usable for the communication of the first communication system 102_1), while subscribers of the second communication system 102_2, such as a base station 104_2 and a plurality of endpoints 106_5-106_8, can communicate wirelessly with each other based on a second channel access pattern (e.g., which specifies a frequency-hopping-based allocation (e.g., of resources) of the frequency band usable for the communication of the second communication system 102_2), wherein the first channel access pattern and the second channel access pattern are different (e.g.,have an overlap in the resources used of less than 20%, ideally have no overlap).

[0121] As already mentioned, the communication systems (e.g. the first communication system 102_1 and the second communication system 102_2) are uncoordinated with each other.

[0122] The fact that the communication systems 102_1, 102_2, 102_3 are uncoordinated with each other refers here to the fact that the communication systems do not exchange information among themselves (= between the communication systems) about the respective channel access pattern used, or in other words, that one communication system has no knowledge of the channel access pattern used by another communication system. The first communication system 102_1 is therefore unaware of which channel access pattern is used by another communication system (e.g., the second communication system 102_2).

[0123] Examples thus refer to a communication arrangement 100 of mutually uncoordinated and possibly also unsynchronized radio networks (or communication systems) 102_1, 102_2 for data transmission, which access a shared frequency band. In other words, there are at least two radio networks 102_1, 102_2, each operating independently of one another. Both networks 102_1, 102_2 use the same frequency band.

[0124] Examples assume that only a (small) portion of the frequency band is used for each individual data transmission, such as a frequency channel or a sub-frequency channel. For example, the frequency band can be divided into (sub-)frequency channels, with a frequency channel being a true subset of the entire frequency band. The totality of all available frequency channels constitutes the used frequency band. The transmission of a message (data packet) can, for example, be carried out sequentially over a series of different frequency channels using the telegram splitting method. In this case, examples are particularly useful.

[0125] Networks (or communication systems) 102_1, 102_2 are often arranged in such a way that transmission signals from participants in one network (e.g., the communication system 102_2) can also be received by participants in other, nearby networks (e.g., the communication system 102_1). Consequently, they appear there as interference signals, which can fundamentally significantly impair the performance of a radio transmission system, as described in Fig. 2 is shown.

[0126] In detail, Fig. 2 a schematic view of two mutually uncoordinated networks 102_1, 102_2, each with a base station (BS 1) 104_1, (BS 2) 104_2 and four associated terminals 106_1-106_4, 106_5-106_8. In other words, Fig. 2shows an example network topology for two networks 102_1, 102_2 with base stations (BS 1) 104_1, (BS 2) 104_2, and four terminal devices 106_1-106_4, 106_5-106_8. The red dashed arrows 108 symbolize potential interference signals, i.e., the radio subscribers can receive the transmission signals of the subscribers from the other network as interference signals. Depending on the circumstances, a large number of networks may be within reception range of one another, meaning that the subscribers (base stations or terminal devices) may be exposed to a significant number of interference sources from other networks.

[0127] If (as mentioned above) the frequency band is divided into individual, non-overlapping frequency channels as a shared resource, the impact of interference can be significantly reduced. In coordinated networks, each network can be assigned a portion of the frequency band (a set of frequency channels) exclusively, thus minimizing mutual interference. This is not possible in completely uncoordinated networks.

[0128] In examples, therefore, access to the physical transmission medium (ie the physical radio channel) in each network is designed in such a way that at least one of a) the channel access, i.e. the frequency and time occupancy of the radio channel, in a network, has as little overlap in time and frequency as possible with the channel access in other networks of the same standard (high degree of "orthogonality"), b) the channel access has a (pseudo-)random character within desired specifications (e.g. average access frequency per time period) ("randomness"), c) to the extent that the specifications allow, no longer sequences of identical (in time and frequency) channel access occur between networks ("avoidance of systematic overlaps"), d) all frequency channels within the frequency band are used as evenly as possible in order to achieve the highest possible frequency diversity and, if applicable, compliance with official regulatory requirements ("equal distribution of frequency channel usage"), e) the information on the frequency and time occupancy of the radio channel, e.g.for new participants joining a network with the least possible signaling effort ("reduction of signaling information"), . is fulfilled.

[0129] In simple terms, mutual interference between multiple networks (inter-network interference) is reduced in examples by channel access to the shared frequency band being different in frequency and time, preferably as "orthogonal" as possible and with (pseudo-)random character.

[0130] For illustrative purposes, it is assumed below that, in addition to the division of the frequency band into discrete frequency channels (indices c0, c1, c2,...), a temporal discretization of accesses within each network also takes place. The associated temporal resources are referred to as timeslots and are Fig. 3with the indices t0, t1, t2,... However, both requirements (discretization in frequency and time) are not necessary prerequisites for the application of examples.

[0131] In detail, Fig. 3 A diagram showing the division of the frequency band into resources and a frequency- and time-hopping-based allocation of the frequency band's resources defined by two different channel access patterns. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0132] For example, subscribers of the first communication system 102_1 can communicate wirelessly with each other based on the first channel access pattern 110_1, which specifies a frequency-hopping-based allocation of resources of the frequency band usable for the communication of the first communication system 102_1, while subscribers of the second communication system 102_2 can communicate wirelessly with each other based on the second channel access pattern 110_2, which specifies a frequency-hopping-based allocation of resources of the frequency band usable for the communication of the second communication system 102_2, wherein the first channel access pattern and the second channel access pattern are different (e.g., have an overlap of less than 20%, ideally have no overlap).

[0133] In other words, Fig. 3shows, in the form of a grid, an overview of all fundamentally available resources in frequency and time (schematic representation of the frequency channels and time slots as well as exemplary channel access patterns), wherein an individual resource element in the first communication network 102_1 is determined by assigning a frequency channel index and a time slot index. By way of example, the resources that can be allocated by the first communication network 102_1 are the resource elements identified by reference symbol 112_1. The set of all resources that can be allocated within a communication network represents a channel access pattern 110_1. For the first communication network 102_1, these are all resource elements identified by reference symbol 112_1, which are connected by arrows. In an equivalent manner, the channel access pattern of a further communication network (e.g., the second communication network 102_2) is in Fig. 3entered as an example (all resource elements identified by reference numeral 112_2, which are connected by arrows), which is not anchored in the same frequency and time grid as the first communication network 102_1 (resource elements are shifted in frequency and time from the basic grid of the first communication network 102_1).

[0134] It is important to distinguish between all fundamentally (maximally) available resource elements, ie the total set of all resource elements from which the channel access pattern selects a suitable subset (in Fig. 3 e.g. all elements of the grid), all resource elements actually included in the channel access pattern (in Fig. 3all resource elements marked with reference number 112_1) and the quantity of resource elements (of the channel access pattern) that are actually used in the network for data transmission (for example, with a low data volume, only every third resource element present in the channel access pattern could actually be used).

[0135] The design of the channel access pattern therefore also means determining the actively usable resource pool for this communication network (or communication system).

[0136] The following describes examples of base stations, endpoints, and / or communication systems that use channel access patterns for communication that meet at least one of the above criteria a) to e). Furthermore, examples of generating such channel access patterns are described below. A.1. Base station, endpoint and communication system

[0137] Fig. 4shows a schematic block diagram of a communication system 102 with a base station 104 and a plurality of endpoints 106_1-106_4, according to an example.

[0138] As in Fig. 4 As shown in one example, the communication system 102 may include a base station and four endpoints 106_1-106_4. However, the communication system is not limited to such examples; rather, the communication system may include one or more endpoints 106_1-106_n, where n is a natural number greater than or equal to one. For example, the communication system may include 1, 10, 100, 1,000, 10,000, or even 100,000 endpoints.

[0139] The participants (= base station 104 and endpoints 106_1-106_4) of the Fig. 4The communication system shown uses a frequency band (e.g. a license-free and / or authorisation-free frequency band, e.g. ISM band) for mutual communication, which is used by a plurality of communication systems for communication, as described above with regard to the Fig. 1 to 3 The communication system 102 operates in an uncoordinated manner with respect to the other communication systems that use the same frequency band.

[0140] The base station 104 can be configured to transmit a signal 120, wherein the signal 120 comprises information about a channel access pattern 110, wherein the channel access pattern indicates a frequency- and / or time-hopping-based occupancy (e.g. of resources) of the frequency band usable for the communication of the communication system 102 (e.g. a temporal sequence of frequency resources usable for the communication of the communication system (e.g. distributed over the frequency band), wherein the information describes a state of a number sequence generator for generating a number sequence, wherein the number sequence determines the channel access pattern.

[0141] For example, the state of the number sequence generator can be an internal state of the number sequence generator, whereby a number in the number sequence can be derived from the internal state of the number sequence generator. Based on the internal state of the number sequence generator, subsequent internal states of the number sequence generator can also be determined, from which subsequent numbers in the number sequence can also be derived. For example, the number in the number sequence can be derived directly from the internal state of the number sequence generator (e.g. state = number), e.g. when implementing the number sequence generator as a counter, or via a mapping function, e.g. when implementing the number sequence generator as a shift register, possibly with feedback.

[0142] At least one of the endpoints 106_1-106_4 may be configured to receive the signal 120 with the information about the channel access pattern 110 and to determine the channel access pattern 110 based on the information about the channel access pattern, wherein the information describes a state of a number sequence generator for generating a number sequence, wherein the number sequence determines the channel access pattern.

[0143] For example, the base station 104 and / or at least one of the endpoints 106_1-106_4 may be configured to pseudorandomly determine the channel access pattern depending on the state of the number sequence generator, such as using a pseudorandom mapping function.

[0144] Furthermore, the base station 104 and / or at least one of the endpoints 106_1-106_4 can be configured to pseudorandomly determine the channel access pattern depending on individual information of the communication system (e.g., intrinsic information of the communication system, such as a network-specific identifier).

[0145] Examples of generating channel access patterns are described below. The channel access patterns are generated by the base station 104 and can be determined based on the signal with the information 120 about the channel access pattern from at least one (or all) of the Fig. 4The channel access patterns are determined by the endpoints 106_1-106_4 shown, for example, by a controller (control device, control unit) 130 implemented in the base station 104 and / or in the endpoints 106_1-106_4. The channel access patterns are specified (exclusively) by the base station 104, while the endpoints 106_1-106_4 only "know" the channel access pattern, i.e., they generate it using the same method as the base station 104.

[0146] The following description assumes a radio transmission system (or a communications arrangement) with several independent, uncoordinated communication networks whose participants are within mutual reception range, so that transmitted signals from participants in one network can potentially cause interference for participants in other networks. For the application of the examples, it is not necessary for information (data or signaling information) to be exchanged between different networks. It is also irrelevant whether the networks are synchronized with each other in terms of time and / or frequency.

[0147] Furthermore, it is assumed that within each network there is a coordinating entity (hereinafter referred to as the "base station") that can transmit information about the channel access pattern used within the network to the non-coordinating participants in the network (hereinafter referred to as "end devices" or "endpoints"). This information can be transmitted, for example, via regularly transmitted beacons, but can also be transmitted at irregular intervals or, if necessary, specifically to individual end devices or groups of end devices.

[0148] Furthermore, it is assumed that the entire frequency band available for transmission is divided into a large number of individual frequency channels, each of which can be accessed individually or in subsets (groups of frequency channels).

[0149] Without limiting the generality and for the sake of clarity, the following explanations assume that within each network there is a fixed, discrete time frame at which channel accesses can occur (see also Fig. 3 Channel access in the form of transmitting a signal can be performed by both end devices and the base station. However, channel access does not necessarily have to occur in a resource designated for this purpose in the channel access pattern, for example, if no data or other information is pending transmission.

[0150] Fig. 5 shows a schematic block diagram of a controller 130 for generating a channel access pattern, according to an example.

[0151] As in Fig. 5As can be seen, the controller 130 may include a memory 132, a periodic number generator 134 for generating a periodic number sequence Z, a randomizing allocator 136, and a frequency / time allocator 138.

[0152] The memory (e.g., a register) 132 can be configured to hold a network-specific identifier ID 140, e.g., an (individual) bit sequence that does not change. The periodic number generator 134 can be configured to provide its state 142 or a number 142' derived from its state of the periodic number sequence. The randomizing assigner 136 can be configured to determine a pseudorandom number R 144 depending on the state 142 of the number sequence generator 134 or the number 142' derived therefrom of the periodic number sequence and the network-specific identifier ID 140. The frequency / time assigner 138 can be configured to determine frequency information f 146 and time information t 148 based on the pseudorandom number R 144.For example, the frequency information f 146 and the time information t 148 can describe or define a frequency channel and a time slot (or a frequency channel index and a time slot index) and thus a resource of the channel access pattern.

[0153] The controller 130 can, for example, as shown in Fig. 4 indicated - be implemented in the base station 104 and / or in the one or more endpoints 106_1-106-4 to calculate the individual (or network-individual) channel access pattern used by the communication system 102.

[0154] In other words, Fig. 5 shows the basic structure for generating channel access patterns, according to an example.

[0155] The generation of the channel access patterns is iterative, ie the Fig. 5The blocks shown are called once per generation of a single channel access information. Calling them N times thus generates a channel access pattern with N channel accesses.

[0156] The function of the subblocks is explained in detail below. The term "number" is used. This generally refers to discrete information that can be represented in various ways (e.g., in decimal form, as a binary sequence, or similar). Network-specific identifier "ID"

[0157] The network-specific identifier is a fixed number that is determined by an external entity (e.g., during network configuration or the coordinating base station). Ideally, it varies from network to network. For example, it could be a unique, sufficiently long base station ID, a unique network ID, or a sufficiently long hash of each of them. This value is fixed and, in the arrangement shown, is the only one that does not vary from call to call. Periodic number generator "Z"

[0158] The periodic number generator 134 generates a sequence of numbers Z that repeats periodically with periodicity P. It has an internal state S n , from which the next generated number and the next internal state S n+1 can be uniquely determined. The crucial feature is that the entire periodic sequence for any time step can be derived from a single internal state (which exists at any time step). A simple example is a modulo P counter that periodically produces the number sequence 0, 1, 2... (P-1). Another example is a deterministic random number generator (pseudo-random number generator), e.g. implemented in the form of a feedback shift register (LFSR). A third example is a finite field (Galois field) with P elements. Randomizing assigner

[0159] The randomizing allocator 136 generates an output number R from the two input numbers ID and Z, ie R=map_rand(ID, Z), where map_rand the Assignment function. The assignment is as random as possible, ie a mathematically correlated input sequence (consisting of ID, Z) produces an output sequence R that is as uncorrelated as possible.

[0160] Examples of random assignment are Concatenation of the two input numbers, the application of a cyclic redundancy check (CRC for short) to the input variables ID, Z, which leads to the number R and has a randomizing character, the application of a hash function, the application of an encryption, e.g. AES encryption, whereby the associated key is known to all authorized participants and which thus also represents a method for introducing "transport layer security" (TLS for short).

[0161] The sequence of elements of the number R is pseudorandom in nature according to the above criteria. It should vary from network to network to avoid overlaps in channel access patterns as much as possible. Frequency / time allocator

[0162] The frequency / time allocator 138 allocates to each input number R a 2-tuple of frequency information (radio frequency f) and time information (access time t) by means of a mapping, ie (f,t)= map _ft(R), where "map_ft" represents the assignment function. While the sequence of frequencies can, in principle, be arbitrary within the specified frequency band, the time points must be monotonically increasing from call to call, since "jumps" in time are not permitted.

[0163] Of particular importance is the case where channel access is discretized in frequency and time directions (as described above), i.e., in the form of discrete frequency channels and discrete time slots. In this case, the frequency / time allocator assigns each input number R a 2-tuple of frequency channel index fi and time slot index ti, i.e., (fi,ti) = map_ft(R). The time slots are indexed in ascending chronological order, since "backwards" in time are not permitted. Further details on time slot allocation can be found in Section 3.

[0164] The sequence of 2-tuples (f,t) or (fi, ti) is based on the sequence of elements of R and defines the channel access pattern.

[0165] The precise design of the frequency / time allocator, together with the probability function of the number R, determines the access statistics to the channel. State signaling and predictability

[0166] The Fig. 5 The arrangement shown generates a channel access pattern that depends on both a time-invariant, network-specific identifier and a state-dependent (and thus time-varying) periodic number generator (periodicity P). The network-specific identifier ensures that networks with different network-specific identifiers always generate different sequences of R, even if their number generators are in the same state. This ensures that different networks do not generate identical channel access patterns and thus, in the worst case, experience a "permanent collision" of channel accesses.

[0167] To determine the channel access pattern used in the network, a terminal device requires both the network-specific identifier and the current state of the periodic number generator.

[0168] The network-specific identifier The device receives this identifier upon initial network registration. This is preferably transmitted via beacon signals regularly transmitted by the base station and made accessible to all authorized devices. Alternatively, the network-specific identifier can also be made known to the device during initial configuration (upon delivery), i.e., before initial network operation.

[0169] The condition of the periodic number generator can be transmitted either in a regular beacon signal and / or in dedicated state signaling resources. A number generator with periodicity P has P internal states, so that to transmit the respective state log 2 P Bits must be transmitted. The amount of information transmitted per status signal (number of bits) can thus be controlled as required by the selected periodicity of the number generator.

[0170] The information transmitted for status signaling can be transmitted in the form of several pieces of information, with transmission occurring at different frequencies. For example, if the periodic number generator (Z) is a counter, the most significant bits (MSBs) of the counter could be transmitted separately from the least significant bits (LSBs) and at a different frequency (e.g., less frequently). Even if it is not a counter, the entire status information could be transmitted in the form of several pieces of status information with different transmission frequencies.

[0171] Due to the periodicity of the number generator, a terminal device that knows the state of the number generator at at least one point in time can determine the entire channel access pattern for any point in time / time slot in the future. This allows the terminal device, for example, to deactivate the transmit / receive unit in a power-saving idle state and, upon subsequent activation of the transmit / receive unit, to predict the then-valid section of the channel access pattern from the last previously known state. The base station can thus transmit the state information at comparatively long intervals.

[0172] In summary, the method described here has the advantage that the combination of a network-specific identifier and a periodic number generator creates a comparatively large state space for the (pseudo-random) number R. This prevents the channel access patterns of networks with different network-specific identifiers from being identical, thus minimizing systematic collisions between channel accesses of different, uncoordinated networks. This proves particularly advantageous in the Telegram Splitting Multiple Access (TSMA) method.

[0173] Advantageous features of the frequency-time mapper are explained in more detail in the following sections. Another example of the controller

[0174] According to Fig. 5 and the above description requires a periodic number generator 134. This is replaced in the following example as follows.

[0175] Real-world radio networks are often operated with a beacon signal that is transmitted regularly. Each beacon transmission can be assigned a counter that corresponds to a beacon sequence index. This beacon sequence index is referred to here as the "beacon index."

[0176] It is also common for time slots in a time slot based system to be provided with a time slot index counter (ascending in time direction) (see also Fig. 3 ). This is referred to here as the "time slot index." The beacon index is reset to zero at certain intervals specified by the system, thus exhibiting a periodicity. The same applies to the time slot index (which, for example, starts again at zero after a beacon transmission).

[0177] Fig. 6 shows a schematic block diagram of a controller 130 for generating a channel access pattern, according to an example.

[0178] The controller 130 may include a memory 132, a first buffer 135_1, a second buffer 135_2, a randomizing mapper 136, and a frequency / time mapper 138.

[0179] The memory (e.g., a register) 132 can be configured to hold a network-specific identifier ID 140, e.g., an (individual) bit sequence that does not change. The first buffer (e.g., a register) 135_1 can be configured to hold a periodic beacon index Z1 143_1. The second buffer (e.g., a register) 135_2 can be configured to hold a periodic time slot index Z2 143_2. The randomizing allocator 136 can be configured to determine a pseudorandom number R 144 depending on the periodic beacon index Z1 143_1, the periodic time slot index Z2 143_2, and the network-specific identifier ID 140. The frequency / time allocator 138 may be configured to determine frequency information f 146 and time information t 148 based on the pseudorandom number R 144.For example, the frequency information f 146 and the time information t 148 can describe or define a frequency channel and a time slot (or a frequency channel index and a time slot index) and thus a resource of the channel access pattern.

[0180] In other words, Fig. 6 shows a modified basic structure for generating channel access patterns with beacon index and time slot index. In Fig. 6 An example is shown in which, compared to the Fig. 5 In the example shown, the periodic number generator (output Z) 134 has been replaced by the two blocks "periodic beacon index" (output Z1) 135_1 and "periodic time slot index" (output Z2) 135_2. All other blocks are functionally unchanged (the randomizing allocator now has three inputs).

[0181] The Fig. 5 and 6The controllers 130 shown enable the generation of network-specific channel access patterns, which have at least one of the following properties: The channel access patterns contain as few overlapping subsequences as possible, there is (e.g. in areas with high network density) a large supply of channel access patterns, the channel access patterns are designed in such a way that they have a very high periodicity, the channel access patterns lead (if corresponding requirements exist) to an averagely uniform use of the available frequency channels, the signaling of the applied pattern is carried out by the coordinating instance with as little signaling information as possible, and terminal devices can, even after receiving the complete signaling of the channel access pattern once, determine the content of the channel access pattern at any future point in time (this enables terminal devices, e.g.to insert longer reception pauses for energy saving reasons and to determine the then valid channel access pattern on the basis of information received before the reception pause when switching on again. A.2. Control of channel access in the frequency domain

[0182] To simplify the following illustration, it is assumed that the frequency range (or frequency band) is divided into discrete frequency channels and that transmission is carried out using the TSMA method.

[0183] Mobile radio channels typically exhibit signal attenuation that varies with frequency. If a data packet is transmitted as multiple sub-packets according to the TSMA method, and the underlying mobile radio channel is unknown at the transmitter, the average transmission error rate can be reduced or even minimized by distributing the individual sub-packets across the entire frequency range (utilizing frequency diversity).

[0184] For this reason, it can be advantageous (especially if a data packet consists of only a few partial data packets) to ensure that the frequency channels on which the partial data packets are transmitted have a certain (minimum) distance in the frequency range relative to each other.

[0185] Since the channel access pattern within a network significantly determines the frequency hopping behavior in TSMA, a suitable procedure can be used to ensure that there is a minimum distance between two consecutive frequency channels of the channel access pattern.

[0186] The frequency / time allocator 138 (see Fig. 5 or 6 ) can therefore be designed to determine frequency information f and time information t based on the pseudorandom number R, wherein the frequency information f indicates a distance between two consecutive frequency channels.

[0187] The frequency / time allocator 138 in Fig. 5 or 6 , which determines absolute frequency channels independently from access to access on the basis of the pseudorandom number R, can therefore alternatively also determine distances between two consecutive frequency channels.

[0188] Fig. 7 shows a schematic block diagram of a section of the controller 130, according to an example. As in Fig. 7 can be seen, the frequency / time allocator 138 (see Fig. 5 or 6 ) be designed to determine frequency information and time information based on the pseudorandom number R, wherein the frequency information indicates a distance Δfi n between two consecutive frequency channels.

[0189] As in Fig. 7As can also be seen, the controller 130 may comprise a mapper 150, which may be configured to map the distance Δfi n between two consecutive frequency channels to a frequency channel index fi, for example by means of a combiner (e.g. adder) 152 and a delay element 154.

[0190] In other words, Fig. 7 shows the generation of frequency jumps with minimum and / or maximum jump width. In Fig. 7 It is illustrated that the frequency / time allocator 138 of Fig. 5 or 6 is now replaced by a frequency difference / time allocator 138, which no longer provides absolute frequency channel indices at its immediate output, but rather frequency channel index differences.

[0191] By means of a suitable mapping function (Δfi,t)=map_Δft(R) in the frequency difference / time allocator, it can be ensured that only frequency channel index jumps Δfi n =fi n+1 -fi n (from channel access n to channel access n+1) occur which, for example, lie within a desired range, e.g., Δfi max ≥Δfi≥Δfi min for Δfi>0 and Δfi max ≥(-Δfi)≥Δfi min for Δfi<0. There are numerous methods for implementing such a restriction, which themselves are not the subject of the invention. An exemplary implementation in the form of a corresponding program code for MATLAB (with which Fig. 8 was generated) can be found in the appendix.

[0192] Fig. 8 shows a diagram of a histogram based on a Monte Carlo simulation of the variable Δfi (difference of the frequency channel index Δfi between temporally adjacent channel accesses).

[0193] In the example shown, 72 frequency channels are available. The parameters associated with the simulation results are Δfi min =21, Δfi max =51, i.e., the spacing between two consecutive accesses in the channel access pattern is between 21 and 51 frequency channels.

[0194] By suitable modifications of the exemplary program code, which are easily understood by the person skilled in the art, other distribution forms for Δfi can be generated (e.g. uniform distribution in the range from -Δfi min to -Δfi max or +Δfi min to +Δfi max ) than in Fig. 8 shown. A.3. Specification of the temporal channel access activity

[0195] In a heavily loaded system, all available time slots can be included in the channel access pattern. In less heavily loaded systems, not every time slot needs to be available for channel access. This is illustrated in the following figure.

[0196] Fig. 9shows a diagram of a frequency- and time-hopping-based allocation of the resources 112 of the frequency band defined by a channel access pattern 110, as well as a projection of the channel access pattern 110 onto a time axis, according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0197] In other words, Fig. 9 The upper part shows an example of a channel access pattern 110 in the dimensions of frequency and time (resource elements 112), and the lower part shows its projection onto the time dimension. It can be seen that not every time slot is part of the channel access pattern 110.

[0198] Thus, in addition to the frequency dimension (in the form of the frequency channel index), the time dimension (in the form of the time slot index) is also available for generating a pseudorandom channel access pattern 110. When generating a channel access pattern, an average activity rate A can thus be specified. This is defined here as the average ratio of time slots used for channel access to the total maximum available time slots. If every time slot is used, the activity rate A is thus 1 (100%). If, on average, only every third time slot is included in the channel access pattern, the average activity rate A is 1 / 3.

[0199] The activity rate therefore determines the (temporal) density of the resources 112 offered in the channel access pattern 110.

[0200] The time slots selected for channel access at a given activity rate can be pseudorandomly selected from a suitable part of the pseudorandom number R (see Fig. 5 or 6 ) can be determined. Example 1

[0201] In each step n, an integer rn can be derived from the corresponding pseudorandom number R n , which can assume values ​​between r min and r max , i.e., r min ≤ rn ≤ r max . After each time slot active in the channel access pattern 110, a number of rn time slots can be skipped, which are thus not used for channel access. This process is exemplified in Fig. 10 shown.

[0202] In detail, Fig. 10 in a diagram projected onto a time axis, resource elements 112 of a channel access pattern 110 resulting in unused time slots, according to an example.

[0203] In other words, Fig. 10shows an exemplary sequence of used and unused time slots, according to an example.

[0204] If the number r is derived from the number R in such a way that the elements of r occur with equal frequency between r min and r max (uniform distribution), the following activity rate results: A = 2 / 2 + r min + r max .

[0205] The method presented in the above example has the advantage that minimum and maximum intervals can be specified between the time slots active in channel access pattern 110. Specifying minimum intervals can be particularly advantageous for battery-operated devices, where transmission pauses of a certain minimum length between two consecutive transmissions (recovery phase) increase battery life.

[0206] In a comparable approach, it can be specified that a minimum number of active time slots follow one another directly. Example 2

[0207] In an implementation according to Example 1, longer periods with locally significantly higher or lower activity rates than desired could theoretically occur. This effect is avoided in the following example.

[0208] Here, groups of consecutive time slots are periodically specified, within each of which an active time slot of the channel access pattern is placed. This is for an activity rate of 1 / 4 (25%) in Fig. 11 shown as an example.

[0209] In detail, Fig. 11 in a diagram projected onto a time axis, resource elements 112 of a channel access pattern 110 with an activity rate A=1 / 4, according to an example.

[0210] In other words, Fig. 11 shows an exemplary sequence of used and unused time slots, according to an example.

[0211] As in Fig. 11 As can be seen, the time slots can be clustered into 114 (in the example of Fig. 11 of length 4). Exactly one time slot of the channel access pattern 110 is placed in each cluster 114. The position of the time slots included in the channel access pattern 110 within the cluster 114 can be determined by a shift vn, which is derived from the pseudorandom number Rn and can assume integer values ​​between 0 and (cluster length - 1).

[0212] In the event that a minimum distance between two consecutive time slots of the channel access pattern 110 is to be ensured, non-occupyable areas can be introduced between the clusters 114. These can consist of one or more time slots, as shown in Fig. 12 is illustrated.

[0213] In detail, Fig. 12in a diagram projected onto a time axis, resource elements 112 of a channel access pattern 110 with an activity rate A=1 / 4 and a predetermined minimum distance between consecutive time slots of the channel access pattern 110, according to an example.

[0214] In other words, Fig. 12 shows an exemplary sequence of used and unused time slots with unassignable time slots, according to an example.

[0215] As in Fig. 12 As can be seen, due to the unassignable time slots, the permissible range of the shift variable vn is reduced to the value range from 0 to (cluster length-1-length of the unassignable range).

[0216] Depending on the selected activity rate, clusters 114 may need to have different lengths to achieve the desired activity rate. In this case, the value range of vn varies according to the respective cluster length. For example, to set an activity rate of 40%, clusters of length two and length three can alternate. A.4. Channel access patterns with areas of different activity rates

[0217] Data packets that are to reach the receiver as quickly as possible (short latency) require channel accesses that are as close together as possible during transmission, i.e. a comparatively high activity rate in the channel access pattern.

[0218] For data packets where transmission reliability (e.g., high robustness against external interference) is paramount, spreading the transmission over a longer period of time can be advantageous, thus resulting in a comparatively low activity rate in the channel access pattern. The same applies to devices where temporally equalized energy consumption from the battery (time-stretched transmission activity) is desired.

[0219] As shown above, the activity rate, ie the frequency of channel access, can be specified by appropriate measures. In order to meet the possibly different requirements in a network, a channel access pattern can be designed in such a way that it has areas with different activity rates. This is Fig. 13 shown as an example. Depending on individual requirements, end devices can then transmit in the range most suitable for them.

[0220] In detail, Fig. 13 a temporal division of a channel access pattern 110 into areas of different activity rates A 1 , A 2 and A 3 , according to an example.

[0221] In other words, Fig. 13 shows an example of a channel access pattern with three areas of different activity rates within the channel access pattern 110. A.5. Demand-dependent (dynamic) adjustment of the activity rate of the channel access pattern

[0222] In networks (or communication systems) 102, different load situations may exist at different times. As explained above, the actively usable resource pool for this network can be determined by designing the channel access pattern 110 (ie, its activity rate or average temporal density).

[0223] Providing a high resource reserve (high activity rate) with a low actual load can be disadvantageous, especially for battery-powered devices. An example of this is a battery-powered base station (e.g., in a PAN network, possibly in repeater mode), which operates the receiver and thus consumes energy during all active resources of the channel access pattern.

[0224] Therefore, it may be useful to dynamically adapt the average activity rate, i.e., the temporal density of the resources offered by channel access pattern 110, to the prevailing load conditions. If the activity rate of channel access pattern 110 changes, this is signaled accordingly to the participants in the network, for which, for example, the beacon signal (or dedicated signaling resources) can be used.

[0225] If a terminal device 106 is in a prolonged idle state (energy-saving mode), it may not receive the signaling information transmitted by the base station 104 during the idle state via a possibly modified channel access pattern. In such a scenario, it may be useful for a channel access pattern 110 to provide a minimum pool of (basic) resources that is available at all times and without special signaling, as well as an additional pool of resources that can be added depending on the load and is subject to appropriate signaling.

[0226] In the above sense, additional resources added to the channel access pattern can, for example, be arranged after the basic resources in time or can be arranged interleaved with them in the time / frequency grid, as shown in Fig. 14 is shown.

[0227] In detail, Fig. 14A diagram showing a frequency- and time-hopping-based allocation of resources 112 of the frequency band defined by a channel access pattern 110, wherein the channel access pattern 110 additionally comprises resources 112* that can be activated as needed, according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0228] In other words, Fig. 14 shows an example of entangled basic and additional resources. A.6. Adaptive frequency range allocation

[0229] In certain unlicensed frequency bands, users may be able to decide for themselves, without regulatory restrictions, which frequency ranges they use within the frequency band. This may result in certain areas of the available frequency band being more heavily occupied by external users than others and thus being more exposed to interference.

[0230] If a base station 104 detects such medium- or long-term asymmetric utilization of the frequency band (e.g., through frequency-channel-by-frequency signal-to-interference power estimates based on received signals), the above-average occupied area of ​​the frequency band can be avoided for use by its own network by not including the associated frequency channels in the channel access pattern. This is implemented in the frequency / time allocator (see Fig. 5 or 6 ) and is signaled to all network participants in an appropriate manner.

[0231] The group of excluded frequency channels can be described, for example, by a corresponding start and end frequency channel index or by a start frequency channel index and a following channel number.

[0232] Fig. 15shows a diagram of a frequency- and time-hopping-based allocation of resources 112 of the frequency band defined by a channel access pattern 110, wherein a frequency range 115 of the frequency band that is regularly subject to greater interference is not occupied by the channel access pattern 110, according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0233] As in Fig. 15 As can be seen, a frequency range 115 that is regularly subject to greater interference (e.g., heavily occupied by external networks) is taken into account when generating the channel access pattern 110. Frequency channels in this frequency range 115 are therefore not included in the channel access pattern 110.

[0234] In other words, Fig. 15 shows an example of excluding heavily disturbed frequency channels from the channel access pattern.

[0235] By avoiding interference-prone frequency ranges for data transmission in your own network, a certain load balancing across the frequency band is achieved by ensuring that other networks in the already heavily used frequency ranges do not experience additional interference. A.7. Bundling of resource elements in the frequency domain (frequency channel bundling)

[0236] Depending on the hardware and software used, it is possible for a base station 104 to receive on multiple frequency channels simultaneously (frequency channel bundling). In this case, it is particularly advantageous for systems with higher loads to increase the number of resource elements offered within the network in the frequency dimension accordingly and to include multiple frequency channels within a time slot in the channel access pattern, as described in Fig. 16 is shown.

[0237] In detail, Fig. 16A diagram showing a frequency- and time-hopping-based allocation of resources 112 of the frequency band defined by a channel access pattern 110, wherein resources 112 are bundled in the frequency domain, according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0238] In other words, Fig. 16 shows an example of the channel access pattern 110 when bundling three adjacent frequency channels into resource clusters. Fig. 16 The bundling of three frequency channels is shown as an example. Each group of resource elements of a time slot can be referred to as a "resource cluster." The channel access pattern 110 can be supplemented with information about the number of frequency channels that constitute a resource cluster.

[0239] As a further example, it should be mentioned that the frequency channels grouped into resource clusters do not necessarily have to be directly adjacent.

[0240] The following shows how one or more participants of a communication system 102 can access a selection of the resources released for the communication system 102 by the network-specific channel access pattern 110 using a relative channel access pattern. B. Channel access via relative channel access patterns

[0241] The examples in this Section B and its subsections are not in accordance with the invention and are for illustrative purposes only.

[0242] Fig. 17 shows a schematic block diagram of a communication system 102 with a base station 104 and two endpoints 106_1-106_2, according to an example.

[0243] The Fig. 17The communication system 102 shown comprises, by way of example, a base station 104 and two endpoints 106_1-106_2. However, the communication system is not limited to such examples; rather, the communication system 102 may comprise one or more endpoints 106_1-106_n, where n is a natural number greater than or equal to one. For example, the communication system may comprise 1, 10, 100, 1,000, 10,000, or even 100,000 endpoints.

[0244] As already explained in detail above (see e.g. Fig. 4) The participants (= base station 104 and endpoints 106_1-106_2) of the communication system use a frequency band (e.g., a license-free and / or authorization-free frequency band, e.g., ISM band) for mutual communication, which frequency band is also used for communication by a plurality of communication systems. The communication system 102 operates in an uncoordinated manner with respect to the other communication systems that use the same frequency band.

[0245] As was also explained in detail above, the base station 104 is designed to transmit a signal 120, wherein the signal 120 comprises information about a network-specific channel access pattern 110, wherein the network-specific channel access pattern 110 indicates a frequency- and / or time-hopping-based occupancy of resources of the frequency band that can be used for the communication of the communication system 102, while the endpoints 106_1-106_2 are designed to receive the signal 120 and to determine the network-specific channel access pattern 110 based on the information about the network-specific channel access pattern (see e.g. Fig. 5 and 6 ).

[0246] For mutual communication, ie for mutual transmission of data, the participants (e.g. base station 104 and endpoint 106_1) of the communication system 102 can use a relative channel access pattern which specifies which of the resources released or usable for the communication of the communication system 102 by the network-specific channel access pattern 110 are actually to be used for the transmission of the data.

[0247] In detail, the base station 104 may be configured to transmit data 160 (e.g., a signal including the data 160) using a relative channel access pattern (e.g., to send to the endpoint 106_1 and / or to receive from the endpoint 106_1), wherein the relative channel access pattern specifies an allocation of resources to be used for the transmission from the usable frequency- and / or time-hopping-based allocation of resources of the network-specific channel access pattern 110.

[0248] The endpoint 106_1 may be configured to transmit data 160 (e.g., a signal including the data 160) using the relative channel access pattern (e.g., receive it from the base station and / or transmit it to the base station 104), wherein the relative channel access pattern indicates an allocation of resources to be used for the transmission from the usable frequency- and / or time-hopping-based allocation of resources of the network-specific channel access pattern.

[0249] For mutual communication between other participants (e.g. base station 104 and endpoint 106_2) of the communication system 102, a different relative channel access pattern can be used, which indicates which of the resources released or usable by the network-specific channel access pattern 110 for the communication of the communication system 102 are actually to be used for the transmission of the data, wherein the relative channel access pattern (e.g. from endpoint 106_1) and the other relative channel access pattern (e.g. from endpoint 106_2) are different.

[0250] For example, the base station 104 may be further configured to transmit data 162 (e.g., a signal including the data 162) using a different relative channel access pattern (e.g., to transmit to the other endpoint 106_2 and / or to receive from the other endpoint 106_2), wherein the different relative channel access pattern specifies an allocation of resources to be used for the transmission from the usable frequency- and / or time-hopping-based allocation of resources of the network-specific channel access pattern, wherein the relative channel access pattern and the different relative channel access pattern are different.

[0251] The other endpoint 106_2 may be configured to transmit data 162 (e.g., a signal including the data 162) using the other relative channel access pattern (e.g., to receive from the base station 104 and / or to transmit to the base station 104), wherein the other relative channel access pattern specifies an allocation of resources to be used for the transmission from the usable frequency- and / or time-hopping-based allocation of resources of the network-specific channel access pattern, wherein the relative channel access pattern and the other relative channel access pattern are different.

[0252] Examples of the application and generation of relative channel access patterns are described below. The relative channel access patterns can be determined by the subscribers (e.g., the base station 104 and at least one of the endpoints 106_1-106_2), for example, by the controller 130 implemented in the subscribers.

[0253] The following examples refer to the examples described in Section A, which, in the case of the coexistence of several uncoordinated radio networks (e.g. LPWAN, PAN) within mutual reception range, design access to a shared frequency band in such a way that the cross-network, mutual interference between the participants or their adverse effects on transmission security are reduced or even minimized.

[0254] The following description assumes a communication arrangement of mutually uncoordinated radio networks for data transmission that access a shared frequency band. Some examples assume that the so-called Telegram Splitting Multiple Access (TSMA) method is used for data transmission, as described, for example, in [1]. In this method, a data packet protected by channel coding is split into several sub-data packets, which are transmitted using several different time and / or frequency resources.

[0255] Furthermore, some examples assume that there is a coordinating entity within each network (hereinafter referred to as the "base station" or "PAN coordinator" in the context of the IEEE standard [2]), which can transmit information about the channel access pattern used within the network to the non-coordinating participants in the network (hereinafter referred to as "terminals" or "endpoints"). The channel access patterns described above (see Section A) define a set of radio resources (resource elements) that are generally available for transmission within a network for a specific period of time. They thus define the range of resources (valid for the period in question) determined by the base station to which the terminals can access.

[0256] In channel access procedures, a fundamental distinction is made between "contention-free access" and "contention-based access." In contention-free access, a terminal device is assigned uniquely specified radio resources for exclusive use by the coordinating entity (base station). In contention-based access—to which examples refer—the terminal device has access to a range of radio resources, which it can use independently as needed, i.e., without individual resource allocation. A characteristic of this approach is that other terminal devices can also access the same range, which can lead to conflicts in accessing the shared radio resources. The goal is to reduce or even avoid these conflicts wherever possible.

[0257] Examples therefore deal with techniques that make the distribution of available resources (which have been determined by the base station) as effective as possible, so that interference between the participants within the network is reduced or even minimized.

[0258] Examples refer to a hierarchical division of channel access when applying the TSMA method: The base station specifies a range of available radio resources in the form of the network-specific channel access pattern (see Section A). The channel access patterns are designed to organize access by multiple, uncoordinated networks to a shared frequency band in such a way that participants in different networks interfere with each other as little as possible (goal: separation of the networks from each other). The selection and use of radio resources from the aforementioned network-specific channel access pattern ("range") by end devices in the form of a relative channel access pattern. The relative channel access pattern is hierarchically subordinate to the network-specific channel access pattern and cannot use resources that lie outside the network-specific channel access pattern. The indexing of resources can therefore advantageously be performed relative to the network-specific channel access pattern.The different relative channel access patterns have the task of providing several participants within a network (possibly within the same period of time) with access to the shared resource offer within the framework of contention-based access, whereby the participants within the network should interfere with each other as little as possible (goal: separation of the participants within a network).

[0259] Examples include a pool of relative channel access patterns known to both the base station and the network's terminals, from which the terminal uses one for each transmission, for example. The selection of a relative channel access pattern from the available pool can be based on various criteria and is described in more detail below. B.1. Channel access via hierarchically organized channel access patterns

[0260] As explained above, examples refer to the hierarchical structure of the channel access pattern of network participants consisting of two components: a network-specific channel access pattern, which determines the availability of radio resources in the respective network at a given time (see Section A), and a relative channel access pattern. This determines which of the available resources are actually occupied / used during a data transmission.

[0261] The actively used relative channel access pattern of a network participant thus consists of a subset of the network-specific channel access pattern.

[0262] The application of the examples described here is particularly advantageous for data transmission using the TSMA method, in which a data packet is transmitted divided into a number of sub-packets. For illustrative purposes and without limiting its generality, the following description assumes that the frequency band is divided into a number of discrete frequency channels and that accesses within a network are temporally discretized in the form of time slots.

[0263] Fig. 18shows, in a diagram, a frequency- and time-hopping-based usable allocation of resources 112 of the frequency band, specified by a network-specific channel access pattern 110, an allocation of resources 118 to be used for transmission, specified by a relative channel access pattern 116, from the usable allocation of resources 112 of the network-specific channel access pattern 110, as well as projections of the channel access patterns 110, 116 onto time axes before and after removal of unused resources (e.g., time slots), according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0264] As in Fig. 18As can be seen, the network-specific channel access pattern 110 defines the distribution of the resources 112 of the frequency band (e.g. each defined by time slot and frequency channel, or time slot index and frequency channel index) that can be used by the communication system 102 and thus by the subscribers (base station 104 and endpoints 106_1-106_2) of the communication system 102 for mutual communication, while the relative channel access pattern 116 indicates those resources 118 from the usable resources 112 that are actually used by a subset of the subscribers (e.g. a limited group of subscribers, e.g. by two subscribers, such as base station 104 and endpoint 106_1) of the communication system 102 for mutual communication.

[0265] In other words, Fig. 18shows a schematic example of the network-specific and relative channel access pattern (hierarchical structure of channel access). Fig. 18 The upper part shows an example of the division of radio resources into a multitude of resource elements in a discrete time / frequency grid. A resource element is described by a frequency channel index and a time slot index. Fig. 18 A network-specific channel access pattern 110 is shown, which is highlighted by resource elements 112 that are symbolically connected by arrows. This network-specific channel access pattern 110 represents the range of resource elements 122 provided by a network (or communication system) 102. In this example, signal transmission is only possible on one frequency channel in a time slot.

[0266] If the two-dimensional representation is projected onto the time axis and all unoccupied time slots in the network-specific channel access pattern 110 are removed, the "available resources" 112 result according to the above representation. The time indexing can advantageously be performed here by a relative time slot index, which is relative to the network-specific channel access pattern.

[0267] In the lowest part of the Fig. 18 A relative channel access pattern 116 is shown as an example, which defines a subset of the available resources (or possibly all of them). The channel access pattern effectively resulting from the selected example (ie the hierarchical combination of network-specific and relative channel access pattern) is in all areas of the Fig. 18by resource elements 118. The relative channel access pattern with its relative time slot index can be recalculated to the original discrete time grid using the average activity rate A defined in Section A. This average activity rate is defined as the average ratio of time slots used for channel access to the total maximum available time slots. When every time slot is used, the activity rate A is thus 1 (100%). However, as in Fig. 18 As shown in the upper part, on average only every second time slot is included in the channel access pattern (i.e. 10 out of 20), the average activity rate is A=1 / 2. B.2. Bundling of resource elements in the frequency domain (frequency channel bundling)

[0268] Depending on the hardware and software used, it is possible for a base station 102 to receive on multiple frequency channels simultaneously (frequency channel bundling). In this case, it is advantageous, especially for systems with higher loads, to increase the number of resource elements offered within the network in the frequency dimension accordingly and to include multiple frequency channels within a time slot in the network-specific channel access pattern 110. This is described in Fig. 19 shown.

[0269] In detail, Fig. 19in a diagram, a frequency- and time-hopping-based usable occupancy of resources 112 of the frequency band bundled in the frequency domain, specified by a network-specific channel access pattern 110, an occupancy of resources 118 to be used for transmission, specified by a relative channel access pattern 116, from the usable occupancy of resources 112 of the network-specific channel access pattern 110, as well as projections of the channel access patterns 110, 116 onto time axes before and after removal of unused resources (e.g., time slots). The ordinate describes the frequency channel indices, and the abscissa the time slot indices.

[0270] As in Fig. 19As can be seen, the network-specific channel access pattern 110 in the frequency direction (eg per time slot or time slot index) indicates a bundling of resources 112, ie a plurality of adjacent resources 112 (eg frequency channels or frequency channel indices) of the frequency band, wherein the relative channel access pattern 116 in the frequency direction indicates at most a subset (eg at most one resource, ie one or no resource) of the plurality of adjacent resources 112 of the network-specific channel access pattern 110.

[0271] In other words, Fig. 19 shows a schematic exemplary representation of the network-specific channel access pattern 110 and the relative channel access pattern 116 with gapless frequency channel bundling.

[0272] This shows Fig. 19For example, a bundling of three contiguous frequency channels per occupied time slot. Accordingly, in the relative channel access pattern 116, in addition to the temporal dimension, the occupancy of the (in the example: three) frequency channels is also available as a degree of freedom.

[0273] The procedure described above can also be used if the multiple frequency channels available within a time slot are not present as a (completely) contiguous area, but are distributed in a different way across the available frequency channels, as described in Fig. 20 is shown.

[0274] Fig. 20shows, in a diagram, a frequency- and time-hopping-based usable occupancy of resources 112 of the frequency band spaced apart from one another in the frequency domain, specified by a network-specific channel access pattern 110, an occupancy of resources 118 to be used for transmission from the usable occupancy of resources 112 of the network-specific channel access pattern 110, specified by a relative channel access pattern 116, an occupancy of resources 119 to be used for transmission from the usable occupancy of resources 112 of the network-specific channel access pattern 110, specified by another relative channel access pattern 117, as well as projections of the channel access patterns 110, 116, 117 onto time axes before and after removal of unused time slots or frequency channels, according to an example. The ordinate describes the frequency channel indices and the abscissa the time slot indices.

[0275] As in Fig. 20As can be seen, the network-specific channel access pattern 110 indicates in the frequency direction (e.g. per time slot or time slot index) a bundling of resources 112, i.e. a plurality of spaced-apart resources 112 (e.g. frequency channels or frequency channel indices) of the frequency band, wherein the relative channel access pattern 116 indicates in the frequency direction at most a subset (e.g. at most one resource, i.e. one or no resource) of the plurality of spaced-apart resources 112 of the network-specific channel access pattern 110, and wherein the other relative channel access pattern 117 indicates in the frequency direction at most a subset (e.g. at most one resource, i.e. one or no resource) of the plurality of spaced-apart resources 112 of the network-specific channel access pattern 110, wherein the relative channel access pattern 116 and the other relative channel access pattern 117 are different.

[0276] In other words, Fig. 20 shows a schematic exemplary representation of the network-specific channel access pattern 110 and the relative channel access pattern 116 in the case of gapped frequency channel bundling.

[0277] The advantage of this frequency channel bundling is that, as shown in Fig. 20 Additionally shown relative channel access pattern 117 of a second subscriber (e.g. user) significantly less adjacent channel interference (the channel separation of two directly adjacent channels is always problematic due to the limited filter effect, especially when one channel is received with a significantly stronger reception power than the adjacent channel) as in Fig. 19 occurs.

[0278] The advantage of the Fig. 19 and 20The bundling described above is to grant more end devices within the network access to the radio resources within a given period of time (higher load). Alternatively, for a given load, channel bundling can reduce the probability of channel access collisions, as a given access volume is distributed across more potential resource elements (reduced mutual interference between users within the network). The advantage of frequency channel bundling over the use of more time slots is also greater energy efficiency, as the receiver switches on for fewer time slots with the same number of resource elements available.

[0279] If a terminal device has the capability to transmit on multiple frequency channels simultaneously, this can be provided for in the relative channel access pattern. This is illustrated in the following figure, which is limited to the relative channel access pattern only (corresponding to the lower part of Fig. 19 and 20 ).

[0280] Fig. 21 shows a diagram showing a projection of a network-specific channel access pattern 110 and a relative channel access pattern 116 onto the time axis after removing unused frequency channels and time slots, wherein the relative channel access pattern 116 in the frequency direction occupies several of the resources 112 available in the frequency direction for at least some of the time jumps. The ordinate represents the relative frequency channel indices, and the abscissa represents the relative time slot indices.

[0281] In other words, Fig. 21shows a diagram of a relative channel access pattern 116 for frequency channel bundling with simultaneous transmission (e.g. emission) on several frequency channels. B.3. Allocation of resources with channel accesses at different symbol rates

[0282] In the above explanations, it was assumed, for example, that the signal on each frequency channel is generated with an identical symbol rate. However, if, as described above, a range of several immediately adjacent frequency channels is available, this range, referred to below as a "resource cluster," can be divided into several sub-resources. These sub-resources can be assigned different symbol rates and / or a different number of symbols, as described in Fig. 22 is illustrated.

[0283] Fig. 22shows a diagram of a frequency- and time-hopping-based usable allocation of resources 112 of the frequency band, which are bundled in the frequency domain into blocks (or clusters) 113, specified by a network-specific channel access pattern 110, wherein different parts 111_1-111_4 of the block 113 of contiguous resources 112 are assigned different symbol rates and / or different numbers of symbols, according to an example. The ordinate represents the frequency channel indices, and the abscissa represents the time slot indices.

[0284] In other words, Fig. 22 shows a formation of resource clusters 113 with sub-resources 111_1-111_4 of different symbol rates and number of symbols per time slot (example).

[0285] This shows Fig. 22An example of a section of a channel access pattern with a sequence of resource clusters 113, which are constituted by bundling five frequency channels each. Each resource cluster 113 is divided into four independent sub-resources "A" (111_1), "B" (111_2), "C" (111_3), and "D" (111_4), in which different multiples of the symbol rate fs and the number of symbols N s are used. For example, with a double symbol rate and a given number of symbols, two consecutive accesses by two different participants can occur in a time slot due to the shortened symbol duration. This is shown in Fig. 22 This is the case for the temporally successive partial resources "B" (111_2) and "C" (111_3).

[0286] The advantage of this approach is that within the network-specific channel access pattern 110, resources can be allocated with different symbol rates and thus transmission bandwidths as required.

[0287] It is readily apparent to those skilled in the art that the division of resource clusters 113 formed by frequency channel bundling into individual sub-resources can be accomplished in a variety of ways. The symbol rates used in this process do not necessarily have to be integer multiples of a basic symbol rate (as in the chosen example). The same applies to the number of symbols in the sub-resources. B.4 Criteria for generating relative channel access patterns

[0288] Different transmission scenarios may result in different requirements for the relative channel access pattern 116.

[0289] Data packets that are to reach the receiver as quickly as possible (short latency) require channel accesses to be transmitted in as short a sequence as possible, i.e., a comparatively high activity rate A in the network-specific channel access pattern, as described in Section A. However, for data packets where transmission reliability (e.g., high robustness against external interference) is paramount, distributing the transmission over a longer period of time can be advantageous, thus, a comparatively low activity rate A in the network-specific channel access pattern can be advantageous. The same applies to devices where temporally equalized energy extraction from the battery (time-stretched transmission activity) is desired.

[0290] It is therefore advantageous to design the set of available relative channel access patterns in such a way that needs-based channel access patterns with desired properties are available for different scenarios.

[0291] The key design parameters for a set of K relative channel access patterns are in frequency direction the number of F specified frequency channels within a time slot, in the time direction the number of Z available time slots with a specified duration T RE , where only one resource element per time index element in Z the average activity rate specified in Section A A , with the help of which an absolute time slot length can be calculated from the relative time slot length Z / A This can then be used for a given period of time T RE of a resource element the total frame duration T Frame = T RE • (Z / A)in seconds, the number of D Partial data packets into which a data packet is divided, as well as the error correction code used in the data packet, which can be, for example, a block or convolutional code with a given code rate R Typically, the number of partial data packets is significantly smaller than the number of resource elements available in the time direction, i.e. D « Z .

[0292] Fig. 23 shows a diagram projecting a network-specific channel access pattern 110 and a relative channel access pattern 116 with D resources 112 onto the time axis after removing unused resources (frequency channels and time slots), according to an example. The ordinate represents the relative frequency channel indices, and the abscissa represents the relative time slot indices.

[0293] Fig. 23 shows a representation of a resource frame with F x Zresources and an absolute total length of T RE • (Z / A) seconds.

[0294] In a first design step, based on the total frame duration T-Frame and the network-specific activity rate A from section A and the time duration T RE to determine the number of available resource elements for a resource element.

[0295] When determining the total frame duration T Frame = T RE • (Z / A) It depends on the application. For an application requiring low latency, such as a wireless light switch, doorbell, or door opener, T Frame should not exceed 500 ms. For latency-insensitive applications where robustness against external interference is more important, the duration of a resource frame can easily reach values ​​of 5 to 10 seconds.

[0296] The network-specific activity rateA from Section A is influenced by the application case. For latency-critical applications, the activity rate should be relatively high, i.e. between A=0.33 and 1. With a value of 0.33, on average only every third time slot is included in the network-specific channel access pattern 110, while the other two time slots are not used in this network. For latency-free applications, especially for battery-operated devices, the activity rate values ​​can be as high as A=0.1 sink.

[0297] Finally, the duration T RE of a partial data packet or resource element. For a symbol rate f S For example, with a speed of around 2500 Sym / s and a number of 30 to 80 symbols per partial data packet, values ​​of 12 to 32 ms result for T RE .

[0298] From the application-specific specifications for T-Frame , T RE and Athe number Z of resources available in the time direction can be determined. Together with the F The total resources available per resource frame are then calculated from the given frequency channels. As shown in Fig. 24 As shown in the table, these values ​​can vary considerably depending on the application.

[0299] In detail, Fig. 24 in a table a resource calculation for various exemplary use cases.

[0300] Based on the first design step, the number of resources available in the resource frame FxZ resource elements are determined, the second design step is to determine the length D of each channel access pattern and the available F x Z Resource elements, the number M to determine the different channel access patterns.

[0301] Depending on the F x Zavailable resource elements there are M max = Z ! · F D / Z − D ! · D ! different channel access patterns of length D that differ in at least one resource element. In Eq. (1) it was assumed that a pattern per time slot index contains only one resource element from all F frequency channels, see Fig. 20 For the first example from the Fig. 24 shown table and a D =4, according to equation (1) M max = 70 and for the last case a Mmax = 8x10 46< with an assumed D = 24 . Would a simultaneous transmission of several partial data packets on several frequency channels be permitted, as Fig. 21 shown, then M max increase massively again.

[0302] Advantageously, the number DThe number of subpackets should be chosen as large as possible, as this ensures the greatest robustness against interference from other participants, regardless of whether they originate from the same or from external networks. Typically, in IoT-based TSMA transmission, a data packet is broken down into 10 to 30 subpackets. If a transmission time corresponding to this number of subpackets is not available, as is the case with some latency-critical applications, the value of D also be smaller.

[0303] In general, the larger the number M The more available channel access patterns are selected, the lower the probability of a full collision. A full collision occurs when two end devices both randomly select the same channel access pattern for their transmission. For example, M = 128different patterns are available, the probability of a full collision is 0.78125% (1 / 128), if it is assumed that each terminal selects its channel access pattern randomly from the M available patterns. M = 1024 This collision probability drops to 0.0977%. In the event of a full collision, it can be assumed that, depending on the reception level ratio, at least the data packet content of the terminal with the weaker reception can no longer be decoded correctly. With similar or identical reception levels, the data packets of both users may even be lost. The advantage of the telegram splitting method described in [1] is that, due to the different channel access patterns, only a few partial data packets collide, which can, however, be reconstructed using the error correction code used.

[0304] Fig. 25shows in a diagram simulation results of the packet error rate for different channel access pattern lengths M as a function of the number of simultaneously active terminals at 360 resource elements. The ordinate represents the packet error rate PER and the abscissa the number of N simultaneously active end devices (e.g. endpoints) in the resource frame.

[0305] In detail, the simulation results from Fig. 25 the course of the packet error rate PER for different lengths M of channel access patterns over the number N of the terminals simultaneously active in the resource frame, whereby a convolutional code with rate R=1 / 3 was used. Furthermore, a F = 1 and Z = 360 provided and the channel access pattern length was D = 18.

[0306] At N = 2 End devices can have different full collision probabilities depending onM The larger the specified M , the lower the failure probabilities of the PER curves of the different channel access pattern lengths. M = 1024 become 1024 different channel access patterns randomly from the M max possible and the N End devices (e.g. endpoints) also always randomly select their used (relative) channel access pattern for the 500,000 transmission attempts. M = 'inf' For each transmission attempt, new channel access patterns are always randomly generated for each individual device (e.g. endpoint). The full collision probabilities for N = 2 is 0% in this case, since according to Eq. (1) almost infinitely many channel access patterns are possible. If the number N of simultaneously active terminal devices, the collision probability of the individual partial data packets increases and the packet error rate increases.N = 10 The packet error rate for all curves is M = 256 until M = 'inf' about 10%.

[0307] As from Fig. 25 As can be seen, the choice of M = 'inf' the best performance. However, on the base station side, the recognition of the different channel access patterns is M = 'inf' almost impossible. In this respect, M must be reduced to a realistic level. For a M max > 10 14< should be a requirement of M = 1024 This choice is also influenced by the computing power available on the receiver side. It is clear that the performance loss compared to the version with M = 'inf' when choosing M = 1024 is not particularly large.

[0308] For smaller values ​​of M max The lengths of the channel access patterns can also be reduced without significant performance losses in the PER. This is Fig. 26 for aZ = 60 and D = 15. The performance curves for the lengths M = 128 until M = 2048 differ only in N = 2 slightly.

[0309] Fig. 26 shows a diagram of simulation results of the packet error rate for various channel access pattern lengths M as a function of the number of simultaneously active end devices with 60 resource elements. The ordinate represents the packet error rate PER, and the abscissa represents the number N of simultaneously active end devices (e.g., endpoints) in the resource frame.

[0310] In summary, the determination of the number M of different channel access patterns depends on M max and is therefore a function of F, Z and D. For M maxFor a value of > 10 14 <, for example, an M = 1024 proves to be reasonable. If the value of M max falls below the threshold of 10 14 <, M can be reduced accordingly. Simulations should be used to verify the extent to which the PER performance still meets the requirements. For very large values ​​of M max, M can certainly assume values ​​even greater than 1024. This can be determined by appropriate simulations.

[0311] In the second design step, the number M of different channel access patterns and their length D were determined. Ideally, the individual channel access patterns are determined using a random generator, which ensures that there is as little correlation or similarity as possible between the M individual patterns. On the receiver side, this usually means a very large detection effort. To reduce this detection effort, the third design step attempts to give the channel access patterns structural properties, such as clustering or repeating patterns, in order to significantly reduce the computational complexity on the receiver side. The PER performance, as shown, for example, in the Fig. 25 and 26 shown, should not worsen as a result.

[0312] One possibility is to divide the resource frame into clusters 114 of equal length L, as shown in Fig. 27 is shown.

[0313] In detail, Fig. 27resources 112 of a channel access pattern 110 projected onto a time axis in a diagram, wherein resources 112 of the channel access pattern 110 are grouped into clusters 114 of equal length L (e.g., L=4), wherein the relative channel access pattern indicates an occupancy of one resource 118 per cluster 114, according to an example. In other words, Fig. 27 shows a channel access pattern with one element per cluster of length L = 4

[0314] A cluster variant would be to increase the length Z of the resource frame by the number of D This results in a maximum cluster length of L = floor(R / D). In the example of Fig. 25 This would result in a cluster length of L = 20 (360 / 18) Resource elements.

[0315] The cluster length can also be smaller than L = floor(R / D)are selected and the remaining resource elements are then used to shift the basic pattern generated from the smaller clusters by one time index step, i.e. by one resource element, in order to generate further patterns that all have the same basic shape.

[0316] In the example Fig. 26 can for example L = 10 From the L x D (= 180) A single channel access pattern is then rolled out from resource elements, which is then R - L x D times, i.e. 180 times, each shifted by one time index step. This results in 181 different channel access patterns, all of which have the same basic pattern. For example, the channel access pattern length M = 1024 out of Fig. 25with only 7 different basic patterns, with each of these basic patterns shifted an average of 145 times along the time axis. Performance deteriorates only slightly.

[0317] Overall, the above approach significantly reduces the detection effort on the receiver side. However, it is important to continually check that performance does not suffer compared to that achieved with purely random sequences. C. Synchronization beacon

[0318] It is assumed below that within each network there is a coordinating entity (hereinafter referred to as "base station") as well as non-coordinating participants (hereinafter referred to as "terminals" or "endpoints").

[0319] Fig. 28 shows a schematic block diagram of a communication system 102 with a base station 104 and an endpoint 106, according to an embodiment of the present invention.

[0320] As in Fig. 28 As shown by way of example, the base station 104 can have a transmitting device (or transmitter, or transmitting module, or transmitter) 172 which is designed to transmit signals, such as the control signal 120. The transmitting device 172 can be connected to an antenna 174 of the base station 104. The base station 104 can further have a receiving device (or receiver, or receiving module, or receiver) 170 which is designed to receive signals, such as the activation signal 122 and the data signal 124. The receiving device 170 can be connected to the antenna 174 or a further (separate) antenna of the base station 104. The base station 104 can also have a combined transceiver.

[0321] The endpoint 106 may have a receiving device (or receiver, or receiving module, or receiver) 182 that is designed to receive signals, such as the control signal 120. The receiving device 182 may be connected to an antenna 184 of the endpoint 106. Furthermore, the endpoint 106 may have a transmitting device (or transmitter, or transmitting module, or transmitter) 180 that is designed to transmit signals, such as the activation signal 122 and the data signal 124. The transmitting device 180 may be connected to the antenna 184 or another (separate) antenna of the endpoint 106. The endpoint 106 may also have a combined transceiver.

[0322] As explained in sections A and B, the communication system 102 is configured to communicate wirelessly in a frequency band used by a plurality of mutually uncoordinated communication systems for communication.

[0323] To coordinate the participants of the communication system 102, a signal or beacon signal 120, also called a control signal, is transmitted, wherein the control signal 120 has information about a network-specific channel access pattern 110, wherein the network-specific channel access pattern 110 indicates a frequency- and / or time-hopping-based occupancy of resources 112 of the frequency band that can be used for the communication of the communication system 120.

[0324] This control signal 120 is transmitted in a distributed manner according to a frequency- and time-hop-based allocation of resources 211 of the frequency band specified by a control signal hop pattern 210. The frequency range 214 of the frequency band over which the control signal 120 is transmitted in a distributed manner according to the control signal hop pattern 210 is substantially larger (e.g., larger by a factor of 5, 10, 15, 20, 30, 40, or 50) than a reception bandwidth of a receiver 182 of the endpoint 106. For example, the control signal 120 can have a plurality of partial control data packets 212, wherein the plurality of partial control data packets 212 are transmitted in a distributed manner in the resources 211 defined by the control signal hop pattern 210.

[0325] In embodiments of the present invention, a reference signal 220 (or synchronization signal) is therefore transmitted by the base station 104 in a predetermined frequency range 224 (e.g., one or more frequency channels) of the frequency band, wherein the reference signal 220 comprises information about the control signal 120.

[0326] As in Fig. 28 As indicated, the reference signal 220 can be transmitted in at least one resource 225 (e.g. defined by frequency channel and time slot) of the predetermined frequency range 224.

[0327] The predefined frequency range 224 is known to the endpoint 106. The endpoint 106 can therefore be configured to set a reception frequency of the receiver 182 to the predefined frequency range 224 during a registration phase in order to receive the reference signal 220.

[0328] In embodiments, the predetermined frequency range 224 may be adapted to a receive bandwidth of the receiver 182 of the endpoint 106.

[0329] For example, the predetermined frequency range 224 may comprise one frequency channel or several adjacent frequency channels, such as two to six (or three to four) adjacent frequency channels. Typically, the receiver 182 of the endpoint 106 has a receive bandwidth of a few hundred kHz (e.g., 100 kHz, 200 kHz, or 300 kHz), wherein the frequency channels into which the frequency band is divided for access by the communication system may have a bandwidth of approximately 50 kHz (e.g., between 30 kHz and 70 kHz).

[0330] After receiving the reference signal 220, the endpoint 106 may determine / extract the information about the control signal 120 from the received reference signal to receive the control signal 120 based on the information about the control signal 120.

[0331] The information about the control signal 120 can, for example, comprise information about the control signal jump pattern 210, such as the control signal jump pattern 210 itself or information from which the control signal jump pattern 210 can be derived, such as a control signal jump pattern index that uniquely identifies the control signal jump pattern 210 from a set of control signal jump patterns to which different control signal jump pattern indices are assigned.

[0332] Furthermore, the information about the control signal 120 may include information about a time and frequency position of the control signal 120 with respect to the reference signal 220.

[0333] Based on this information, the endpoint 106 may then receive the control signal 120, for example, by switching the reception frequency of the endpoint's receiver 182 to the respective resources of the frequency band specified by the control signal hopping pattern 210 (e.g., defined by time slots and frequency channels into which the frequency band is divided).

[0334] Embodiments of the present invention thus enable participants (e.g., endpoint 106) that are not able to receive a full-bandwidth broadband transmission and process it in real time to nevertheless initially synchronize and subsequently log on to the communication network 102.

[0335] In the following subsection, detailed embodiments of the detection process of the control signal 120, hereinafter also called beacon, in which the unique information about the channel access pattern 110 used is located, are described. C.1 Transmission of sync (partial) data packets before the beacon

[0336] The signals used in typical networks with bandwidths of several MHz cannot usually be received and / or processed simultaneously in full bandwidth by participants using very inexpensive hardware and / or are battery-operated.

[0337] Typically, the radio chips installed on such devices can provide a bandwidth of a few hundred kHz. The computing power of such devices is also designed to enable timely processing of these bandwidths.

[0338] In embodiments, a reference signal 220 is therefore transmitted before the control signal 120, wherein the reference signal comprises information about the control signal, wherein the information about the control signal that the reference signal comprises comprises information about the control signal hopping pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the reference signal is transmitted in a predetermined frequency range of the frequency band, wherein the reference signal comprises a plurality of partial reference data packets that contain the information about the control signal, wherein the reference signal is transmitted according to a reference hopping pattern, wherein the reference hopping pattern indicates a frequency- and / or time-hopping-based occupancy of resources of the predetermined frequency range, wherein the endpoint is designed,to receive the reference signal according to the reference hop pattern in order to obtain at least a portion of the plurality of partial reference data packets sufficient for decoding.

[0339] Further embodiments are described below.

[0340] In order for these devices to still be able to synchronize to such a network and subsequently receive the beacon (or the control signal 120), according to embodiments the necessary information for the (relative) channel access pattern (or control signal hopping pattern 210), as well as the frequency and timing of the beacon (the control signal 120) is transmitted within a bandwidth of approximately 100 kHz.

[0341] After extracting the necessary data, the subscriber can determine the temporal position(s) and the frequency channel(s) of the beacon (or the control signal 120) and receive the (partial) packets (or partial control data packets 212) of the beacon (or the control signal 120) accordingly by switching the carrier frequency.

[0342] To achieve this, a so-called sync (partial) data packet (or reference signal 220 with a reference data packet 226) can be transmitted on a fixed frequency at a defined time interval before the beacon (or control signal 120). This sync (partial) data packet (or reference data packet 226) can be used by new participants to determine the beginning of the beacon (control signal 120).

[0343] If the beacon (or the control signal 120) is transmitted by means of a channel access pattern (or control signal hop pattern 210), this sync (partial) data packet (or reference data packet 120) must contain information from which the channel access pattern (or control signal hop pattern 210) as well as the time and frequency position of the beacon (or control signal 120) can be deduced.

[0344] Such a transmission of a sync (partial) data packet (or reference data packet 226) before the actual transmission is in Fig. 29 to see.

[0345] In detail, Fig. 291 shows a diagram illustrating the occupancy of resources 225 of the frequency band during the transmission of the reference signal 220 with a reference data packet 226, as well as the occupancy of resources 211 of the frequency band, indicated by the control signal hopping pattern 210, during the transmission of the control signal 120 with the plurality of partial control data packets 212, according to an embodiment of the present invention. The ordinate represents the frequency in frequency channels, and the abscissa represents the time in time slots. In other words, Fig. 29 shows a transmission of a sync (partial) data packet (or reference data packet 226) before the actual transmission in front of the beacon (or the control signal with the plurality of partial control data packets 212).

[0346] In Fig. 29The sync (partial) data packet (or reference data packet 226) contains information about the channel access pattern (or control signal hop pattern 210) used in the beacon (or control signal 120). The distance between the sync (partial) data packet (or reference signal 220 with the reference data packet 226) and the beacon (or control signal 120) is fixed.

[0347] The next time a beacon (or control signal 120) is transmitted, the channel access pattern (or control signal hopping pattern 210) can be different. This means that the channel access pattern (or control signal hopping pattern 210) is time-variant. The transmission of the sync (partial) data packet (or reference data packet 226) must always occur on the same frequency channel (or within the same frequency range (=predefined frequency range 224)), which is known in advance to the receiver, so that simple receivers can receive it with a low bandwidth.

[0348] In embodiments, before the transmission of the beacon (or the control signal 120), a sync (partial) data packet (or reference data packet 226) is transmitted in a time-referenced manner, which contains the necessary information about the channel access pattern (or control signal hopping pattern 210) used in the beacon (or the control signal 210). C.2 Division of sync (partial) data packets into several partial data packets

[0349] In embodiments, the reference data packet 226 (e.g., synchronization data packet) comprising the information about the control signal 120 is divided into a plurality of partial reference data packets 227, so that each of the partial reference data packets 227 comprises only a part of the reference data packet 226.

[0350] In embodiments, the reference signal 220 is transmitted with the plurality of partial reference data packets 227 according to a reference hop pattern 228, wherein the reference hop pattern 228 indicates a frequency- and / or time-hop-based allocation of resources of the predetermined frequency range 224.

[0351] In embodiments, the plurality of partial reference data packets 227 are channel-coded such that only a subset of the plurality of partial reference data packets 227 is required to successfully decode the reference data packet 226.

[0352] In embodiments, the predetermined frequency range 224 is wider than the reception bandwidth of the receiver 182 of the endpoint 106, wherein, according to the reference hopping pattern 228, at least as many of the plurality of partial reference data packets 227 are transmitted per sub-bandwidth of the predetermined frequency range 224 that corresponds to the reception bandwidth of the receiver 182 of the endpoint 106 as are required for the successful decoding of the reference data packet 226.

[0353] Further embodiments are described below.

[0354] In subsection C.1, a sync (partial) data packet (or reference signal 220 with a reference data packet 226) was introduced, which is transmitted with a time reference to a subsequent beacon (or a subsequent control signal 120). This beacon also contains the information on the composition of the beacon's channel access pattern.

[0355] In comparison to the beacon (or control signal 120), which is typically divided into several partial data packets, the sync (partial) data packet (or reference data packet 226) according to the previous explanations is only a single resource element (or a single data packet which is transmitted in a resource 225 (e.g. defined by frequency channel and time slot)).

[0356] If there is a fault during this transmission, new participants are generally no longer able to extract the data from this sync (partial) data packet (or reference data packet 226).

[0357] The typical bandwidth of a frequency channel in Fig. 29 is below 50 kHz. However, low-cost devices can typically process up to 100 kHz and more in real-time.

[0358] This enables participants to receive and scan at least two frequency channels in parallel.

[0359] It is advisable to also split the sync (partial) data packet (or reference data packet 226) using Telegram splitting. Due to the very limited size of the payload in the sync (partial) data packet (or reference data packet 226), typically no more than five partial data packets (or partial reference data packets) are necessary.

[0360] If coding is used that allows at least one partial data packet (or partial reference data packet) to be lost, the hopping pattern (or reference signal hopping pattern) for the split sync data packet (or reference data packet 226) can be selected such that a larger bandwidth is occupied than can be received by the low-cost subscriber. The only important thing is that the low-cost receiver can always receive at least the minimum number of necessary resource elements, regardless of the quartz offset.

[0361] Fig. 30shows, in a diagram, an occupancy of resources 225 of the predetermined frequency range 224 of the frequency band, defined by a reference signal hop pattern 228, during the transmission of the reference signal 220 with a plurality of partial reference data packets 227, as well as an occupancy of resources 211 of the frequency band, specified by a control signal hop pattern 210, during the transmission of the control signal 120 with the plurality of partial control data packets 212, according to an embodiment of the present invention. The ordinate represents the frequency in frequency channels, and the abscissa represents the time in time slots.

[0362] In other words, Fig. 30 shows a subdivision of the sync data packet (or reference data packet 226) into three subpackets (or partial reference data packets 227), which are transmitted on different frequencies.

[0363] In Fig. 30The sync data packet (or reference data packet 226) was thus divided into three sub-data packets (or sub-reference data packets 227) and transmitted on frequency channels c0 to c2. A pause in transmission could also be inserted between the sub-data packets (or sub-reference data packets 227), and the arrangement of the sub-data packets (or sub-reference data packets 227) at the frequencies could be chosen differently. It is only important that this structure is maintained for all subsequent beacons (or transmissions of the control signal 220) and is known to the subscriber in advance.

[0364] In embodiments, the transmission of the sync data packet (or reference data packet 226) can be divided into partial data packets (or partial reference data packets 227), which are positioned such that a low-cost subscriber can receive at least a portion of these partial data packets (or partial reference data packets 227). This means that at least the minimum number of partial data packets (or partial reference data packets 227) required for error-free reception must be within the bandwidth of the low-cost receiver. C.3 Variation of the frequencies of the sync (partial) data packets

[0365] In embodiments, the reference signal 220 can be transmitted repeatedly (e.g., periodically), wherein the reference signal 220 can be transmitted alternately in at least two predetermined sub-frequency ranges of the predetermined frequency range 224.

[0366] In embodiments, the at least two predetermined sub-frequency ranges can be separated from each other in frequency to such an extent that accidental synchronization to the other predetermined sub-frequency range caused by a frequency offset is not possible.

[0367] In embodiments, the frequency channels of the at least two predetermined sub-frequency ranges can be separated from one another in terms of frequency to such an extent that adjacent frequency channels do not overlap even with a frequency offset.

[0368] In embodiments, an occupancy of resources of the respective predetermined sub-frequency ranges indicated by the reference jump pattern may not have repeating identical distances between the resources in time and / or frequency.

[0369] Further embodiments are described below.

[0370] In the embodiments described in sections C.1 and C.2, the sync (partial) data packet(s) is / are always transmitted on the same frequency or on the same (adjacent) frequencies in order to enable low-cost subscribers to synchronize into the network.

[0371] However, the beacon (or control signal 120) is transmitted over a wider frequency range. This increases the interference immunity of the beacon (or control signal 120) compared to the sync (partial) data packet(s) (or reference data packet 125 / partial reference data packets 127). Furthermore, in static scenarios, it may happen that the few frequency channels of the sync (partial) data packets (or partial reference data packets 127) lie exactly in a fading hole and are therefore never received by a subscriber.

[0372] In embodiments, the transmission of the sync (partial) data packets (or partial reference data packets 127) can periodically change the frequency position before each beacon. This diagram shows Fig. 31 .

[0373] In detail, Fig. 31 1 shows a diagram illustrating the frequency band resource occupancy defined by a reference signal hop pattern 228 during the repeated transmission of the reference signal 220 with the plurality of partial reference data packets 227 in different partial frequency ranges 125_1, 125_2 of the predetermined frequency range 124, as well as the frequency band resource occupancy defined by a control signal hop pattern 210 during the repeated (periodic) transmission of the control signal 120 with the plurality of partial control data packets 212, according to an exemplary embodiment of the present invention. The ordinate represents the frequency in frequency channels, and the abscissa represents the time in time slots.

[0374] In other words, Fig. 31 shows a variation of the frequency channels of the sync (partial) data packets (or partial reference data packets 227). In Fig. 31 In time slot n (or in a first group of time slots (t0, t1, t2) the frequency channels c0 to c2 are occupied and in time slot n+1 (or in a second group of time slots) the channels c3 to c5 are occupied. In time slot n+2 (or in a third group of time slots) the frequency channels c6 to c8 could be occupied accordingly. The term "time slot" here refers to the time between two beacons, ie a time slot includes the reference signal (sync beacon), the control signal (data beacon) and the following data transmission areas.

[0375] Thus, for example, a participant (e.g., endpoint 106) that does not detect any sync (partial) data packets (or partial reference data packets 227) on channels c0 to c2 can change the channel and then look for sync (partial) data packets (or partial reference data packets 227) there. If it does not detect anything there, it could change the channel again, and so on.

[0376] This also allows nodes (or endpoints 106) that have a local, continuous disturbance on certain sub-channels or are in a fading hole to still synchronize in the network.

[0377] In the Fig. 31For illustrative purposes, an ascending order of frequency channels is selected for the consecutive timeslots (or groups of timeslots) in the embodiment shown. However, this is not required, so that in other embodiments, a different sequence of frequency channels (e.g., timeslot n: c0, c1, c2, timeslot n+1: c10, c11, c12, timeslot n+2: c5, c6, c7, etc.) can be determined.

[0378] In embodiments, the frequency channels used for transmitting the sync (partial) data packets (or partial reference data packets 127) are temporally variable. There is a temporal periodicity with which the entire pattern of the sequence of channels is repeated.

[0379] To maximize transmission reliability, it is possible to derive the sync (partial) data packets (or partial reference data packets 227) of the various timeslots (or groups of timeslots) from the same synchronization information, thus allowing any combination of the sync (partial) data packets (partial reference data packets 227) to be used to reconstruct the data. If this is the case, the receiver (e.g., base station 104) cannot unambiguously determine the frequency offset present if the clustering remains constant across the timeslots (or groups of timeslots), since it cannot determine whether the packets belonged to transmission n or n+1 if the frequency offset is greater than the spacing between the clusters.

[0380] In embodiments, the clusters are separated from each other in terms of frequency at least to such an extent that accidental synchronization, due to frequency offset, to the cluster shifted in the frequency domain is not possible.

[0381] Within a cluster, it is also necessary to know exactly which of the subpackets (or partial reference data packets 227) were received. If, in a cluster of three (c0+c1+c2), one of the two outermost sync (sub-)data packets (or partial reference data packets 227) is corrupted, i.e., c0 or c2, the node (or endpoint 102) can successfully synchronize and decode thanks to error protection, but does not know whether it received c0+c1 or c1+c2.

[0382] If the frequency channels cX and cX+1 are far enough apart from each other that it can be clearly determined on which cX the sync (partial) data packet (or partial reference data packet 227) was sent, even despite the frequency offset, this ambiguity no longer exists.

[0383] In embodiments, the frequency channels within a cluster are separated from each other in terms of frequency at least to such an extent that, even with a frequency offset, adjacent channels do not overlap.

[0384] Another solution is to design the clusters so that the frequency hopping pattern (or reference signal hopping pattern 228) is unique within the cluster. For example, not a staircase as shown in the figure, but rather the sequence c0+c2+c1, which, upon successful detection of at least two sync (partial) data packets (or partial reference data packets 227), clearly determines which sync (partial) data packets (or partial reference data packets 227) were received.

[0385] In embodiments, the clusters of the sync (partial) data packets (or partial reference data packets 227) are selected such that there are no repeating identical intervals in time and frequency of the sync (partial) data packets (or partial reference data packets 227) within the cluster. C.4 Dynamic control of the number of sync (partial) data packets used

[0386] In embodiments, the reference signal 220 can be transmitted at predetermined intervals (e.g., periodically), wherein a distance between at least two consecutive transmissions of the reference signal 220 is dynamically adapted to a number of newly registered endpoints, or wherein the reference signal 220 is transmitted, e.g., in response to an external event additionally (e.g., between two planned transmissions of the reference signal 220).

[0387] In embodiments, a number of partial reference data packets 227 with which the reference signal is provided can also be dynamically adapted to the number of new endpoints to be registered.

[0388] In embodiments, a number of different frequency channels of the predetermined frequency range 224, to which the plurality of partial reference data packets 227 are distributed, can also be dynamically adapted to the number of new endpoints to be registered.

[0389] Further embodiments are described below.

[0390] It often happens in networks that there are times when many new participants (e.g. endpoints) want to register in the network (e.g. communication system 102) (e.g. during commissioning), but there are also times when there are hardly any / no new participants for the network.

[0391] Thus, at some times, it is unnecessary to transmit the sync (partial) data packets (partial reference data packets 127), since it is highly unlikely that any new participant (e.g., endpoint 106) will want to register. At other times, many participants want to register, but they have to wait a very long time until they find sync (partial) data packets (or partial reference data packets 227) on the frequency channels selected by the respective participants.

[0392] It is therefore advisable to dynamically configure the number of transmitted sync (partial) data packets (or partial reference data packets). It is also possible to transmit multiple sync (partial) data packets (or partial reference data packets 227) simultaneously, thus transmitting the information multiple times on different frequencies simultaneously. Fig. 31 For example, the transmission from times n and n+1 could occur together at time n and no transmission could occur at time n+1.

[0393] In exemplary embodiments, the number of transmitted sync (partial) data packets (or partial reference data packets 127) is configured dynamically. It is possible to transmit no sync (partial) data packets (or partial reference data packets 127) at certain times; at other times, multiple clusters could be transmitted simultaneously, or all frequency channels intended for transmitting the sync (partial) data packets or partial reference data packets 127) could be occupied.

[0394] New participants (e.g., endpoints 106) are often deployed by a technician during installation. This means the technician deploys new devices, which then automatically connect to the network.

[0395] However, the technician knows when these participants were deployed and can communicate this to the base station 104 (e.g. by pressing a button on the base or a web interface).

[0396] If the base (or base station 104) is informed that new participants (e.g. endpoints 106) want to dial in, it can dynamically send several sync (partial) data packets (or partial reference data packets 127) as described above in order to accelerate the synchronization / registration process.

[0397] In embodiments, the base station transmits more sync (partial) data packets (or partial reference data packets 127) than usual upon notification. C.5 Interlocked clusters when the sync (partial) data packets are repeatedly transmitted in front of a beacon

[0398] In embodiments, the reference signal 220 can be transmitted repeatedly, wherein the reference signal 220 is provided with a plurality of partial reference data packets 227, wherein the plurality of partial reference data packets of at least two, for example, successive transmissions of the reference signal 220 are temporally interleaved according to respective reference signal jump patterns 228.

[0399] In embodiments, the respective reference signal jump patterns 228 are time and frequency shifted versions of each other.

[0400] In embodiments, a time interval between the plurality of partial reference data packets 227 of the respective reference signal 220 may correspond to the number of repetitions.

[0401] Further embodiments are described below.

[0402] If the sync partial data packets (or partial reference data packets 227) are sent repeatedly as described in section C.4, it is possible to temporally interleave at least two transmissions. This is possible in Fig. 32 for a double transmission when divided into three sub-packets (or sub-reference data packets 227).

[0403] In detail, Fig. 32in a diagram, resource allocations of the predetermined frequency range 224 of the frequency band during the multiple transmission of the reference signal 220, indicated by reference signal hopping patterns 228_1, 228_2, such that the plurality of partial reference data packets 227_1, 227_2 of the multiple transmission of the reference signal 220 are temporally interleaved, as well as an allocation of resources of the frequency band during the transmission of the control signal with the plurality of partial control data packets, defined by a control signal hopping pattern 210, according to an embodiment of the present invention. The ordinate describes the frequency in frequency channels, and the abscissa the time in time slots. In other words, Fig. 32 shows a temporal interleaving of two transmissions of sync partial data packets (or partial reference data packets 227_1,227_2).

[0404] The advantage of this temporal interleaving is its immunity to interference, as there is a larger time interval between adjacent frequency channels. Regarding the synchronization characteristics of a new subscriber (e.g., endpoint 106), nothing changes for this subscriber, except that there is a higher latency when receiving the sync partial data packets (or partial reference data packets 227). This is not a problem, since the subscriber has to wait anyway after receiving the sync partial data packets (or partial reference data packets 227) until it can receive the beacon (or the control signal 120 with the control signal data packets 212).

[0405] Since the distance between the last sync partial data packet (or partial reference data packet 227) and the start of the beacon (or the control signal 120 with the control signal data packets 212) varies from cluster to cluster, this distance (ie the temporal start of the beacon) must either be known to the subscriber in advance or be signaled appropriately.

[0406] In embodiments, when the sync partial data packets (or partial reference data packets 127) are repeatedly transmitted before a beacon, the repetitions are nested.

[0407] In the case of multiple repetitions, all transmissions can be nested within each other; in this case, a pause corresponding to the number of repetitions must be left between the partial data packets (or partial reference data packets 227) of a transmission.

[0408] In the Fig. 32In the illustrated embodiment, a single repetition is used, thus, a time slot (German time slot) must be left free between the partial data packets (or partial reference data packets) of the first transmission r0. With a double repetition, this would be two time slots (German time slots), and so on.

[0409] Transmission r1 then begins with the same pattern (corresponding to a cluster) at time step (or time slot) t1. The equidistant selection of the intervals ensures that there is no temporal overlap between the repetitions.

[0410] If two repetitions were used, the second repetition would start in time slot t2.

[0411] In embodiments, a basic cluster is used, which is used for all repeated transmissions.

[0412] In embodiments, the time intervals between the partial data packets (or partial reference data packets 227) within the cluster correspond to the number of repetitions. C.6 Use of known data as a virtual preamble

[0413] In embodiments, the reference signal 220 may be provided with a plurality of partial reference data packets 227, wherein at least two of the plurality of partial reference data packets 227 comprise synchronization sequences known to the endpoint, wherein the at least two of the plurality of partial reference data packets 227 comprise data known to the endpoint 106 (e.g., an ID of the communication system), as will be described below with reference to Fig. 33 is explained.

[0414] Fig. 33 shows a schematic view of one of the plurality of partial reference data packets 227, according to an embodiment of the present invention. As in Fig. 33As shown, the partial reference data packet 227 may include a synchronization sequence 230, known data 232, such as an identification of the communication system 102, and unknown data 234. As shown in Fig. 33 As indicated, the synchronization sequence 230 and the known data 232 form a virtual synchronization sequence.

[0415] Fig. 34 shows a schematic view of the coding and division of the data 231 (=known data and unknown data) of a reference data packet into a plurality of partial reference data packets 227, according to an embodiment of the present invention. As in Fig. 34As can be seen, the data 231 can be encoded, comprising known data 232 and unknown data 234, or provided with an error protection code, in order to obtain coded data 235 comprising coded known data 236 and coded unknown data 237. The coded known data 236 can be interleaved and distributed among the partial reference data packets 227, so that in the respective partial reference data packets 227, the respective parts of the coded known data 236 are arranged directly adjacent to the respective synchronization sequences 230.

[0416] Fig. 35 shows a schematic view of the division of coded data 235 comprising known coded data 236 and unknown coded data 237 into the plurality of partial reference data packets 227, according to an embodiment of the present invention. As in Fig. 35the coded known data 236 are interleaved and divided into the partial reference data packets 227. In contrast to Fig. 35 In the respective partial reference data packets 227, the respective parts of the coded known data 236 are arranged at a predetermined distance from the respective synchronization sequences 230.

[0417] Further embodiments are described below.

[0418] Often, a participant (e.g., endpoint 106) who has not yet connected to a network already knows in advance which network (or communication system 102) he wants to connect to.

[0419] The unique identification of a network is usually done using the network ID or a similar information that is known to the subscriber in advance.

[0420] Typically, a subscriber is within range of multiple networks and must select the correct network (or communication system 102) to which he wishes to connect based on the network ID.

[0421] So that the subscriber does not always have to receive the beacon (or the control signal 120) of a network (or communication system 102), it is useful to include the network ID in advance in the sync (partial) data packets (or reference signal with the partial reference data packets 227).

[0422] If the channel access pattern is calculated according to Section A, this is essential because the network ID is included in the calculation of the channel access pattern.

[0423] The known network ID is thus transmitted in the sync partial data packets (or partial reference data packets 227) and is known to the newly logging-on participant (e.g., endpoint 160) prior to synchronization. When the network ID is transmitted in the sync (partial) data packets (or partial reference data packets 227), the network ID can thus be assumed to be known data (similar to a synchronization sequence).

[0424] If additional known data 232 is available in addition to the synchronization sequence 230, this can also be used for synchronization. The additional data can significantly improve the accuracy of the estimation ("extended virtual synchronization sequence").

[0425] In embodiments, known data 232 (e.g., network ID) is used to improve synchronization.

[0426] If the network ID is inserted directly before or after the fixed synchronization sequence 230 in the sync partial data packets (or partial reference data packets 227), it can be combined with the preamble (or synchronization sequence 230) to form a longer "virtual preamble." This allows for improved synchronization.

[0427] In embodiments, the known data 232 in the sync partial data packets (or partial reference data packets 227) are arranged directly before or after the synchronization sequence 230, so that together with the synchronization sequence 230 an extended contiguous virtual synchronization sequence results.

[0428] When using telegram splitting, the payload data is usually encoded and the partial data packets are interleaved.

[0429] If the network ID is to continue to be used for synchronization, the interleaving must be carried out in such a way that the encoded symbols are still inserted directly before or after the synchronization sequence 230.

[0430] Fig. 34 shows a synchronization sequence 230, which is configured as a preamble and is thus positioned at the beginning of the (partial) subpackets (or partial reference data packets 227). Alternative embodiments can also use a mid- or postamble instead of a preamble.

[0431] Before synchronization, the known data (e.g., network ID) can be encoded (without the following unknown data) in the participant. After applying the interleaver, the previously known symbols for synchronization can be extracted and combined with the known synchronization sequence.

[0432] If a flexible decoder is used for reception, which allows synchronization against more than one contiguous synchronization sequence per subpacket, it may be advantageous not to place the known data at the front, but to place it in the middle or at the end of the subpacket, as this will facilitate frequency and phase estimation if the signal changes over time due to disturbances or tolerances (e.g. mobility of the end nodes), as is the case in Fig. 35 is shown.

[0433] It should be noted that there must be enough known data so that the known data occupies at least two consecutive symbols in the subpackets (or reference data packets 227), since otherwise (depending on the modulation type and intersymbol interference) the known data is not well suited to support synchronization due to the unknown preceding or following data.

[0434] In embodiments, the known data in the partial data packets (or partial reference data packets) are not placed directly before or after the synchronization sequence 230, but are distributed in the packet (or partial reference data packet 227) so that they occupy at least two consecutive symbols at a distance from the synchronization sequence of the partial data packet (or partial reference data packet 227). C.7 Different code rates

[0435] In embodiments, the reference signal 220 may be provided with a plurality of partial reference data packets 227, wherein a number of the partial reference data packets 227 are adapted to an error protection code used for the control signal 120.

[0436] In embodiments, the reference signal 220 and the control signal 120 may be provided with the same error protection code or with error protection codes of comparable performance.

[0437] In embodiments, the plurality of partial reference data packets 227 may be symbolically identical.

[0438] Further embodiments are described below.

[0439] To ensure the highest possible transmission reliability, it is advantageous to provide the transmitted data with an error protection code. Depending on the system requirements, it may be necessary to use more sync (partial) data packets (or partial reference data packets 227) so that the threshold at which the packet (or partial reference data packet 227) can be synchronized is at least below the threshold at which it can be decoded.

[0440] For example, if very low-rate error protection is used in the beacon, this packet can be decoded down to an SNR of 0 dB. If only very few sync (partial) data packets (or partial reference data packets 227) are transmitted, it may happen that the sync (partial) data packets (or partial reference data packets 227) can only be successfully synchronized up to an SNR of 3 dB. In this case, the increased error protection would be wasted energy in the transmission, since without synchronization of the sync (partial) data packets (or partial reference data packets 227) of the beacons (or the partial control data packets 212 of the control signal 120) cannot be received because its position and frequency hopping pattern (or control signal hopping pattern 210) are unknown.

[0441] Accordingly, it is necessary to adapt the number of sync (partial) data packets (or partial reference data packets 227) to the error protection code of the beacon (or the control signal 120) to be used.

[0442] In embodiments, the number of sync (partial) data packets (or partial reference data packets 227) is adapted to the error protection used in the beacon (or in the partial control signal data packets 212 of the control signal 120).

[0443] Since the information in the sync data packet (or partial reference data packet 227) must also be decodable at the same threshold as the beacon, it is useful to provide the sync data packet with an error protection code equivalent to that of the beacon.

[0444] In embodiments, beacons and sync data packets can use the same error protection code.

[0445] In embodiments, beacons and sync packets may use error protection codes that have comparable performance.

[0446] If the sync data packet is very short, it may be useful to use a simple repetition code instead of a common error protection code (e.g. convolutional code) and to pack the full information into each individual sync (partial) data packet (or partial reference data packet 227).

[0447] In embodiments, all sync (partial) data packets (or partial reference data packets) may be symbol-identical. D. Further examples

[0448] Fig. 36shows a flowchart of a method 300 for operating an endpoint of a communication system, according to an embodiment of the present invention. The communication system communicates in a frequency band which is used by a plurality of communication systems for communication [e.g., wherein the communication systems are uncoordinated with each other], wherein a control signal is transmitted in the communication system [e.g., a base station of the communication system] for coordinating the subscribers of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency-hopping-based [e.g., and time-hopping-based] allocation of resources of the frequency band specified by a control signal hopping pattern, wherein the endpoint has a receiver,wherein a reception bandwidth of the receiver is at least a factor of 5 smaller than a bandwidth of the frequency-hopping-based [e.g., and time-hopping-based] occupancy of resources of the frequency band specified by the control signal hopping pattern. The method 300 comprises a step 302 of receiving a reference signal [e.g., synchronization signal] that is transmitted in a predetermined frequency range [e.g., one or more frequency channels] of the frequency band [e.g., by the base station of the communication system], wherein the reference signal comprises information about the control signal. Furthermore, the method 300 comprises a step 304 of receiving the control signal based on the information about the control signal, wherein the information about the control signal that the reference signal compriseshas information about the control signal hop pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the reference signal is transmitted in a predetermined frequency range of the frequency band, wherein the reference signal has a plurality of partial reference data packets that contain the information about the control signal, wherein the reference signal is transmitted according to a reference hop pattern, wherein the reference hop pattern indicates a frequency- and / or time-hop-based occupancy of resources of the predetermined frequency range, wherein the reference signal is received according to the reference hop pattern in order to obtain at least a portion of the plurality of partial reference data packets that is sufficient for decoding.

[0449] Fig. 37shows a flowchart of a method 400 for operating a base station of a communication system, according to an embodiment of the present invention. The communication system communicates in a frequency band that is used by a plurality of communication systems for communication (e.g., wherein the communication systems are uncoordinated with each other). The method 400 comprises a step 402 of transmitting a control signal for coordinating the subscribers of the communication system, wherein the control signal is transmitted in a distributed manner according to a frequency-hopping-based (e.g., and time-hopping-based) allocation of resources of the frequency band specified by a control signal hopping pattern. Furthermore, the method 400 comprises a step 404 of transmitting a reference signal (e.g., a synchronization signal) in a predetermined frequency range (e.g., one or more frequency channels) of the frequency band.wherein the reference signal comprises information about the control signal, wherein the predetermined frequency range is at least 5 times smaller [e.g., narrower] than a frequency range of the frequency band in which the control signal is transmitted in a distributed manner according to the control hop pattern, wherein the information about the control signal that the reference signal comprises comprises information about the control signal hop pattern or information about the resources of the frequency band that can be used by the communication system to transmit the control signal, wherein the reference signal is provided with a plurality of partial reference data packets that contain the information about the control signal, wherein the reference signal is transmitted according to a reference signal hop pattern, wherein the reference signal hop pattern indicates a frequency- and / or time-hop-based occupancy of resources of the predetermined frequency range,wherein a reference data packet with the information about the control signal is divided into the plurality of partial reference data packets, so that each of the partial reference data packets comprises only a part of the reference data packet, wherein the plurality of partial reference data packets are channel-coded, so that only a subset of the plurality of partial reference data packets is required for successful decoding of the reference data packet.

[0450] Embodiments find application in systems for the wireless transmission of data from end devices to a base station or from one or more base stations to end devices. For example, a system may be a personal area network (PAN) or a low-power wide area network (LPWAN), where the end devices may be, for example, battery-operated sensors (sensor nodes).

[0451] Embodiments target use cases in which a message (data packet) is transmitted in multiple sub-data packets using the so-called telegram splitting multiple access (TSMA) method. This application is particularly advantageous when the base station is battery-operated, thus optimizing the operation of the base station receiver in terms of energy consumption.

[0452] As already mentioned, the embodiments described herein can be used to transmit data based on the telegram splitting method between the subscribers of the communication system. In the telegram splitting method, data, such as a telegram or data packet, is divided into a plurality of sub-data packets (or partial data packets, or sub-packets) and the sub-data packets are transmitted from one subscriber to another subscriber (e.g. from the base station to the end point, or from the end point to the base station) of the communication system using a time and / or frequency hopping pattern, wherein the subscriber who receives the sub-data packets reassembles (or combines) them to obtain the data packet. Each of the sub-data packets contains only a part of the data packet.The data packet may also be channel-coded so that only a portion of the sub-data packets is required to decode the data packet error-free.

[0453] When transmitting data based on the telegram splitting method, the sub-data packets can be transmitted distributed among a subset (e.g., a selection) of the available resources of the network-specific channel access pattern. Specifically, the sub-data packets can be transmitted based on the relative channel access pattern, i.e., within the resources of the relative channel access pattern. For example, one sub-data packet can be transmitted per resource.

[0454] Although some aspects have been described in the context of a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in the context of or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the key method steps may be performed by such an apparatus.

[0455] Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory, a hard disk, or other magnetic or optical storage device storing electronically readable control signals that can interact or cooperate with a programmable computer system to perform the respective method. Therefore, the digital storage medium may be computer-readable.

[0456] Some embodiments according to the invention thus comprise a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is carried out.

[0457] In general, embodiments of the present invention may be implemented as a computer program product having a program code, wherein the program code is effective to perform one of the methods when the computer program product is run on a computer.

[0458] The program code can, for example, also be stored on a machine-readable medium.

[0459] Other embodiments include the computer program for performing one of the methods described herein, wherein the computer program is stored on a machine-readable carrier.

[0460] In other words, an embodiment of the method according to the invention is thus a computer program which has a program code for carrying out one of the methods described herein when the computer program runs on a computer.

[0461] A further embodiment of the method according to the invention is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for performing one of the methods described herein is recorded. The data carrier, the digital storage medium, or the computer-readable medium is typically physical and / or non-perishable or non-transient.

[0462] A further embodiment of the method according to the invention is thus a data stream or a sequence of signals that represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can be configured, for example, to be transferred via a data communication connection, for example, via the Internet.

[0463] A further embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to carry out one of the methods described herein.

[0464] A further embodiment comprises a computer on which the computer program for performing one of the methods described herein is installed.

[0465] A further embodiment according to the invention comprises a device or system designed to transmit a computer program for performing at least one of the methods described herein to a recipient. The transmission can be electronic or optical, for example. The recipient can be, for example, a computer, a mobile device, a storage device, or a similar device. The device or system can, for example, comprise a file server for transmitting the computer program to the recipient.

[0466] In some embodiments, a programmable logic device (e.g., a field-programmable gate array, an FPGA) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array may interact with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC.

[0467] The devices described herein may be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0468] The devices described herein, or any components of the devices described herein, may be implemented at least partially in hardware and / or in software (computer program).

[0469] The methods described herein may be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0470] The methods described herein, or any components of the methods described herein, may be implemented at least partially by hardware and / or by software.

[0471] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others 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. Bibliography

[0472] [1] DE 10 2011 082 098 B4 [2] IEEE Std. 802.15.4 - 2015 - IEEE Standard for Low-Rate Wireless Networks, 2015 [3] G. Kilian, H. Petkov, R. Psiuk, H. Lieske, F. Beer, J. Robert, and A. Heuberger, "Improved coverage for low-power telemetry systems using telegram splitting," in Proceedings of 2013 European Conference on Smart Objects, Systems and Technologies (SmartSysTech), 2013 [4] G. Kilian, M. Breiling, H. H. Petkov, H. Lieske, F. Beer, J. Robert, and A. Heuberger, "Increasing Transmission Reliability for Telemetry Systems Using Telegram Splitting," IEEE Transactions on Communications, vol. 63, no. 3, pp. 949-961, Mar. 2015 List of abbreviations

[0473] CRC:Cyclic Redundancy Check LPWAN:Low Power Wide Area Network LSB:Least Significant Bit(s) MSB:Most Significant Bit(s) PAN:Personal Area Network TLS:Transport Layer Security TSMA:Telegram-Splitting-Multiple-Access

Claims

1. A terminal point (106) of a communication system (102), wherein a control signal (120) is emitted in the communication system (102) for coordinating the participants of the communication system (102), the control signal (120) being transferred distributed in correspondence with a frequency hop-based occupancy of resources (211) of a frequency band, indicated by a control signal hopping pattern (210), wherein the terminal point (106) comprises a receiver (182), wherein a receive bandwidth of the receiver (182) is smaller by at least the factor 3 than a bandwidth of the frequency hop-based occupancy of resources (211) of the frequency band, indicated by the control signal hopping pattern (210); wherein the terminal point (106) is configured to receive a reference signal (220), wherein the reference signal (220) comprises information on the control signal (120), wherein the terminal point (106) is configured to receive the control signal (120) based on the information on the control signal (120), wherein the information on the control signal (120), which comprise the reference signal (220), comprise information on the control signal hopping pattern (210) or information on the resources of the frequency band usable by the communication system for transferring the control signal (120), wherein the reference signal (220) is transferred in a predetermined frequency range (224) of the frequency band, wherein the reference signal (220) comprises a plurality of partial reference data packets (227) which contain the information on the control signal (120), wherein the reference signal (220) is transferred in correspondence with a reference hopping pattern (228), wherein the reference hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources (225) of the predetermined frequency range (224), wherein the terminal point (106) is configured to receive the reference signal (220) in correspondence with the reference hopping pattern (228) to obtain at least a part of the plurality of partial reference data packets (227) sufficient for decoding.

2. The terminal point (106) in accordance with claim 1, wherein the terminal point (106) is configured to switch a receive frequency of the receiver (182) of the terminal point (106) to the respective resources (211) of the frequency band, indicated by the control signal hopping pattern (210), based on the control signal hopping pattern (210) to receive the control signal (120).

3. The terminal point (106) in accordance with claim 1 or 2, wherein the information on the control signal (120) comprise information on the time and frequency position of the control signal (120) relative to the reference signal (220).

4. The terminal point (106) in accordance with any of claims 1 to 3, wherein the terminal point (106) is configured to synchronize a timer and / or frequency generator of the terminal point (106) to the reference signal (220).

5. The terminal point (106) in accordance with any of claims 1 to 4, wherein the receiver (182) of the terminal point (106) comprises a receive bandwidth which corresponds to a bandwidth of two to ten directly adjacent frequency channels which the frequency band is divided into, or wherein the receiver (182) of the terminal point (106) comprises a receive bandwidth of 250 kHz or less.

6. The terminal point (106) in accordance with any of claims 1 to 5, wherein the reference signal (220) is emitted in predetermined distances, wherein the reference signal (220) is emitted alternatingly in at least two predetermined partial frequency ranges of the predetermined frequency range known to the terminal point (106).

7. The terminal point (106) in accordance with claim 1, wherein the reference signal (220) is transferred in correspondence with a reference hopping pattern (228), wherein the reference hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources (225) of the predetermined frequency range (224), wherein the resources (225) are defined by frequency channels, wherein at least two adjacent frequency channels of the frequency channels occupied in correspondence with the reference hopping pattern (228) are spaced apart from one another in frequency to such an extent that these do not overlap, not even with a frequency offset.

8. The terminal point (106) in accordance with claim 1, wherein the reference signal (220) is transferred in correspondence with a reference hopping pattern (228), wherein the reference hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources of the predetermined frequency range (224), wherein an occupancy of resources (225) indicated by the reference hopping pattern (228) does not comprise any repetitive identical distances between the resources (225) in time and / or frequency.

9. The terminal point (106) in accordance with any of claims 1 to 8, wherein the reference signal (220) comprises a plurality of partial reference data packets (227), wherein the at least two of the plurality of partial reference data packets (227) comprise information known to the terminal point (106), wherein the terminal point (106) is configured to perform synchronization based on the known information.

10. The terminal point (106) in accordance with any of claims 1 to 9, wherein the control signal (120) and / or the reference signal (120) comprise information on a network-specific channel access pattern (110), wherein the network-specific channel access pattern (110) indicates a frequency hop and / or time hop-based occupancy of resources (112) of the frequency band, usable for communication of the communication system (102).

11. A base station (104) of a communication system (102), wherein the base station (104) is configured to transmit a control signal (120) for coordinating the participants of the communication system (102), wherein the control signal (120) is transferred distributed in correspondence with a frequency hop-based occupancy of resources (211) of a frequency band, indicated by a control signal hopping pattern (210), wherein the base station (104) is configured to transmit a reference signal (220) in a predetermined frequency range (224) of the frequency band, wherein the reference signal (220) comprises information on the control signal (220), wherein the predetermined frequency range (224) is smaller by at least the factor 3 than a frequency range (214) of the frequency band in which the control signal (120) is transferred distributed in correspondence with the control hopping pattern (210), wherein the information on the control signal (120), which comprise the reference signal (220), comprise information on the control signal hopping pattern (210) or information on the resources of the frequency band usable by the communication system for transferring the control signal (120), wherein the base station (104) is configured to provide the reference signal (220) with a plurality of partial reference data packets (227) which contain the information on the control signal (120), wherein the base station (104) is configured to transmit the reference signal (220) in correspondence with a reference signal hopping pattern (228), wherein the reference signal hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources (225) of the predetermined frequency range (224), wherein the base station (104) is configured to split a reference data packet (226) having the information on the control signal (120) into the plurality of partial reference data packets (227) so that each of the partial reference data packets (227) comprises only a part of the reference data packet (226), wherein the plurality of partial reference data packets (227) are channel-encoded so that only a subset of the plurality of partial reference data packets (226) is required for successfully decoding the reference data packet (226).

12. A communication system comprising: a terminal point (106) in accordance with any of claims 1 to 10, and a base station (104) in accordance with claim 11.

13. A method (300) for operating a terminal point (106) of a communication system, wherein a control signal (120) is emitted in the communication system for coordinating the participants of the communication system, wherein the control signal (120) is transferred distributed in correspondence with a frequency hop-based occupancy of resources of a frequency band, indicated by a control signal hopping pattern (210), wherein the terminal point (106) comprises a receiver, wherein a receive bandwidth of the receiver is smaller by at least the factor 3 than a bandwidth of the frequency hop-based occupancy of resources of the frequency band, indicated by the control signal hopping pattern (210), the method comprising: receiving (302) a reference signal (220), wherein the reference signal (220) comprises information on the control signal (120), receiving (304) the control signal based on the information on the control signal, wherein the information on the control signal (120), which comprise the reference signal (220), comprise information on the control signal hopping pattern (210) or information on the resources of the frequency band usable by the communication system for transferring the control signal (120), wherein the reference signal (220) is transferred in a predetermined frequency range (224) of the frequency band, wherein the reference signal (220) comprises a plurality of partial reference data packets (227) which contain the information on the control signal (120), wherein the reference signal (220) is transferred in correspondence with a reference hopping pattern (228), wherein the reference hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources (225) of the predetermined frequency range (224), wherein the reference signal (220) is received in correspondence with the reference hopping pattern (228) to obtain at least a part of the plurality of partial reference data packets (227) sufficient for decoding.

14. A method (400) for operating a base station (104) of a communication system, the method (400) comprising: transmitting (402) a control signal for coordinating the participants of the communication system, wherein the control signal (120) is transferred distributed in correspondence with a frequency hop-based occupancy of resources of a frequency band, indicated by a control signal hopping pattern (210), transmitting (404) a reference signal (220) in a predetermined frequency range (224) of the frequency band, wherein the reference signal (220) comprises information on the control signal (120), wherein the predetermined frequency range is smaller by at least the factor 3 than a frequency range of the frequency band in which the control signal (120) is transferred distributed in correspondence with the control hopping pattern, wherein the information on the control signal (120), which comprise the reference signal (220), comprise information on the control signal hopping pattern (210) or information on the resources of the frequency band usable by the communication system for transferring the control signal (120), wherein the reference signal (220) is provided with a plurality of partial reference data packets (227) which contain the information on the control signal (120), wherein the reference signal (220) is transferred in correspondence with a reference signal hopping pattern (228), wherein the reference hopping pattern (228) indicates a frequency hop and / or time hop-based occupancy of resources (225) of the predetermined frequency range (224), wherein a reference data packet (226) having the information on the control signal (120) is split into the plurality of partial reference data packets (227) so that each of the partial reference data packets (227) comprises only a part of the reference data packet (226), wherein the plurality of partial reference data packets (227) are channel-encoded so that only a subset of the plurality of partial reference data packets (226) is required for successfully decoding the reference data packet (226).

15. A computer program for performing the method in accordance with claim 13 or 14 when the computer program runs on a computer or microprocessor.