Communication Techniques

Abstract

A communication device (15), the communication device (15) is configured to transmit and / or receive a plurality of packets using scheduling relative to a reference time; The communication device (15) is configured to transmit synchronization information (81a, 81b); the communication device (15) is configured to include in the synchronization information (81a, 81b) timing information defining a timing of transmission of the synchronization information (81a, 81b) relative to a reference time; Communications equipment (15). A communication device (16', 16"), the communication device (16', 16") is configured to receive synchronization information (81a, 81b); a communication device (16', 16") configured to transmit and / or receive a plurality of packets using scheduling relative to a reference time; the communication devices (16', 16") are configured to evaluate timing information contained in the synchronization information (81a, 81b) and defining the timing of the transmission of the synchronization information (81a, 81b) relative to a reference time, in order to perform the synchronization; Communications equipment (16', 16").

Description

[Technical field]

[0001] In the following, techniques for communication between at least one first communication device and at least one second communication device are disclosed. For example, the second device may be a facility (e.g., with a wireless front end, e.g., an optical front end, e.g., a VLC communication), and the at least one first device may be one or more devices (e.g., wireless devices, e.g., optical devices). In some examples, the facility (or the second device) is fixed (at least in one front end), and one or more first devices may be mobile. Techniques for synchronization are particularly described. Variable MAC scheduling for real-time optical communication is also disclosed. [Background technology]

[0002] For example, wireless communications (e.g., visible light communications, VLC and other communications, e.g., radio frequency, RF, communications, ultrasonic communications, etc.) between equipment (e.g., with a fixed relay or front end) and one or more devices (e.g., mobile devices) are known.

[0003] In some cases, an elaborate medium access strategy is required, i.e., granted time slots are assigned to each communication device, so that transmission collisions can be avoided. In some cases, contention-based time slots can be provided, for example, to new communication devices to join the communication network. This requires complex synchronization techniques between devices. In some cases, it is decided to use a beacon signal, which is periodically transmitted by a master communication device (which may also be a scheduler) to the other communication devices. The beacon signal is also considered to transmit control signals from the master communication device to the other communication devices.

[0004] However, some problems are nevertheless experienced: in fact, there is a latency from the transmission of the beacon signal, and also a latency for each communication device to process the synchronization, which means that the communication device is not able to carry out the communication before the beacon signal is received and the synchronization is processed, and the communication device has to waste some time waiting.

[0005] Furthermore, different traffic conditions (and different exchange characteristics, such as different urgency rankings) may cause congestion in some cases, i.e. some important packets may experience high delays, leading to unacceptable delays. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO 2020 / 053235 A1 Summary of the Invention [Means for solving the problem]

[0007] The invention is defined in the independent claims.

[0008] Through the present independent claims, it is possible to solve or at least mitigate the above problems. In particular, it is possible to schedule synchronization information (including timing information) at the most available time positions. The synchronization information (or even any control signals) may be delayed, advanced or even skipped in some cases. Thus, when a lot of application data (e.g. uplink or downlink application data for urgent communication, for example) is to be transmitted, the synchronization information may be delayed (or even skipped in some cases).

[0009] The present invention also allows for a less stringent approach to synchronization since it is possible to synchronize devices to a moment in time (e.g., a timing reference or reference time) that is not necessarily the time when a beacon signal is transmitted, and thus synchronization information can be transmitted at any time.

[0010] In particular, synchronization is performed even if the synchronization information is delayed or advanced.

[0011] According to one aspect, a communication device (e.g., including a second communication device, e.g., a coordinator) is provided, The communication device is configured to transmit and / or receive a plurality of packets using scheduling relative to a reference time; The communication device is configured to transmit synchronization information; The communication device is configured to include timing information within the synchronization information that defines the timing of the transmission of the synchronization information relative to a reference time.

[0012] The communications device may be configured to include in the timing information the transmission of synchronization information and a time distance from a reference time.

[0013] The communications device may be configured to include in the timing information information regarding the time distance from the reference time to a next timing reference (eg, the reference time).

[0014] The communication devices may be configured to provide scheduling information to the different communication devices, allocating exclusive time slots to each of the different communication devices.

[0015] The communication device may be configured to provide different communication devices with scheduling information allocating exclusive time slots to the communication devices for the transmission of at least some of the control signals.

[0016] The communication device may be further configured to transmit at least some of the control signals in an event-driven manner.

[0017] The communication device may be such that the control signal includes at least synchronisation information.

[0018] The communication device may be configured to delay or advance the transmission of control signals when a higher layer application requires the sending and / or receiving of a transmission.

[0019] The communication device may be configured to, when an upper layer application requires transmission and / or reception of payload data transmission, check whether at least some slots are free according to the scheduling, and accordingly delay or advance the transmission of control signals in free slots within the same superframe, otherwise wait for the next superframe.

[0020] The communications device may be such that the control signal includes scheduling information for a subsequent transmission.

[0021] The communication device may be such that the control signal includes synchronization information for subsequent transmissions.

[0022] The communication device may be such that the control signal includes announcement information.

[0023] The communication device may be such that the control signal includes random access timing information providing information regarding slots that are grant free.

[0024] The communication device may be such that the control signal includes granted access timing information providing information regarding time slots that are grant free.

[0025] The communication device may be configured to define the scheduling information by taking into account traffic.

[0026] The communication device In case of relatively higher traffic congestion, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower traffic congestion, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. The scheduling information may be defined by:

[0027] The communication device may be such that the urgency of transmission and / or reception is ranked according to an urgency rank, the communication device being In case of relatively higher rank transmissions and / or receptions, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower rank transmissions and / or receptions, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. It is configured as follows.

[0028] The communications device may be configured to define scheduling by restoring time slots for transmission of control signals when a threshold condition is reached.

[0029] The communications device may further comprise a plurality of front-ends configured to simultaneously transmit and / or receive different packets through the different front-ends.

[0030] The communications device may be configured to selectively simultaneously transmit synchronization information in different time slots to different front-ends.

[0031] The communication device may include or be connected to a higher layer application, and the communication device uses information about characteristics of real-time application data streams from the higher layer application.

[0032] The communications device may be such that the information regarding the characteristics of the real-time application data stream includes one or more of the following: periodicity of the application data stream, maximum tolerable delay, maximum tolerable delay variation, maximum tolerable loss ratio of datagrams.

[0033] The communications device may be such that the communications device is configured to use the information regarding the characteristics of the real-time application data stream in such a way that, for example, if the information regarding the characteristics of the real-time application data stream requires a particular maximum latency for transmission and / or reception of a particular transmission, then time slots that are not scheduled for a particular different communications device are given to the different communications device and / or other transmissions from the communications device are shifted towards subsequent time slots.

[0034] The communications device may be configured to transmit and / or receive a plurality of packets as a wireless signal and to transmit synchronization information in the wireless signal.

[0035] The communications device may be configured to transmit and / or receive a plurality of packets as an optical signal, and to transmit synchronization information in the optical signal.

[0036] According to one aspect, a method of communication is provided, comprising: transmitting and / or receiving a plurality of packets using scheduling relative to a reference time; The method further comprises the step of transmitting synchronization information; The step of transmitting the synchronization information includes the step of including timing information within the synchronization information that defines the timing of the transmission of the synchronization information relative to a reference time.

[0037] According to one aspect, a non-transitory storage unit is provided that stores instructions that, when executed by a processor, cause the processor to: Controlling transmission and / or reception of a plurality of packets using scheduling relative to a reference time; and controlling the transmission of synchronization information; The synchronization information includes including timing information within the synchronization information that defines the timing of the transmission of the synchronization information relative to a reference time.

[0038] According to one aspect, a communication device (e.g., a first communication device, e.g., user equipment) is provided, The communication device is configured to receive synchronization information; The communication device is configured to transmit and / or receive a plurality of packets using scheduling relative to a reference time; To perform the synchronization, the communication device is configured to evaluate timing information included in the synchronization information and defining the timing of the transmission of the synchronization information relative to a reference time.

[0039] The communications device may be configured to evaluate, from the timing information, information regarding a time distance from a timing reference to a next timing reference (eg, from a reference time to a next reference time).

[0040] The communications device may be configured to resynchronise by comparing the time position of the measured reference time with the timing information.

[0041] The communications device may be configured to read the timing information to ascertain a time drift relative to the timing information, and thereby correct the time knowledge using the time drift.

[0042] The communications device may be configured to count the number of slots between a current reference time and the beginning synchronization information, compare the counted number of slots to a number encoded in the timing information, thereby calculating an offset, and compensate for the offset by adjusting its timing to the timing information.

[0043] The communication device may be configured to receive scheduling information that assigns exclusive time slots to the communication device and assigns different exclusive time slots to different communication devices such that the communication device transmits in the time slots assigned to it and refrains from transmitting in time slots assigned to different communication devices.

[0044] The communications device may be configured to receive scheduling information that assigns exclusive time slots to a master communications device for transmission of control signals, such that the communications device receives control signals at least in the time slots assigned to the transmission of the control signals.

[0045] The communication devices may be configured to receive at least some control signals in an event-driven manner during unassigned time slots, such that the master communication device can occupy the unassigned slots for transmitting at least some control signals in an event-driven manner without necessarily scheduling those event-driven control signals.

[0046] The communications device may be such that the control signal includes scheduling information for a subsequent transmission.

[0047] The communication device may be such that the control signal includes synchronization information for subsequent transmissions.

[0048] The communication device may be such that the control signal includes announcement information.

[0049] The communication device may be such that the control signal includes random access timing information providing information regarding slots that are grant free.

[0050] The communication device may be such that the control signal includes granted access timing information providing information regarding time slots that are grant free.

[0051] The communication device may be configured to include or be connected to an upper layer application, the communication device being configured to receive payload data from the upper layer application and transmit payload data in accordance with a scheduling, and / or the communication device being configured to transmit the received payload data to the upper layer application in accordance with a scheduling.

[0052] The communication device may be such that if information about the characteristics of a real-time application data stream defined by a higher layer application requires a particular maximum latency for transmission and / or reception of a particular transmission, then time slots not scheduled for the communication device are given to a different communication device.

[0053] The communications device may be configured to estimate, from the timing information, a time distance between the encoded timing information and a measured timing reference (eg, a reference time).

[0054] The communications device may be configured to adjust its internal clock to the encoded timing information in the event of a drift between the encoded timing information and a measured timing reference (eg, a reference time).

[0055] The communications device may be configured to transmit and / or receive a plurality of packets as a wireless signal and to receive synchronization information in the wireless signal.

[0056] The communications device may be configured to transmit and / or receive a plurality of packets as an optical signal, and to receive synchronization information in the optical signal.

[0057] According to one aspect, a method of communication is provided, comprising: receiving synchronization information; transmitting and / or receiving a plurality of packets using scheduling related to the criteria; evaluating timing information included in the synchronization information and defining the timing of the transmission of the synchronization information relative to a reference time, in order to perform the synchronization; Includes.

[0058] According to one aspect, a non-transitory storage unit is provided that stores instructions that, when executed by a processor, cause the processor to: Controlling receipt of synchronization information; Controlling transmission and / or reception of a plurality of packets using scheduling relative to a reference time; evaluating timing information included in the synchronization information and defining the timing of the transmission of the synchronization information relative to a reference time, in order to perform the synchronization; Have them carry out the procedure. [Brief description of the drawings]

[0059] [Figure 1] FIG. 1 illustrates an example of wireless communication. [Diagram 2] FIG. 1 is a diagram illustrating an example of communication. [Diagram 3] FIG. 1 illustrates an example of a support frame according to the present technique. [Figure 4] FIG. 2 is a diagram illustrating an example of a frame including synchronization information. [Diagram 5] FIG. 11 is a diagram illustrating an example of synchronization information. [Figure 6] FIG. 1 illustrates an example of syntax for a communication element. [Figure 7] FIG. 1 illustrates an example of syntax for a communication element. [Figure 8]FIG. 1 illustrates an example of syntax for a communication element. [Figure 9] FIG. 13 is a diagram illustrating an example of communication in a coordinator (base station). [Figure 10] FIG. 2 illustrates an example of a first communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] Initial explanation of some common examples 1 shows a network 10 (hereinafter also called OWPAN for optical wireless personal area network, but which can be generalized to an optical network, or even a wireless network) for wireless communication (e.g. optical communication, or visible light communication, VLC) between at least one second communication apparatus, here a communication facility 15 (which can be, for example, a base station, BS), and at least one first communication apparatus, where the at least one first communication apparatus includes at least one communication device (e.g. user equipment, UE, relay endpoint, REP, mobile device).

[0061] The second communication device (e.g., communication equipment) 15 may include or may be a coordinator 12, which may be a computer-based system (e.g., a processor-based system). The coordinator 12 may be understood in some examples as an intelligent part of the communication equipment 15. In an industrial automation example, the coordinator 12 may also be a piece of fixed equipment associated with some machine or coordinating multiple machines (or associated with a device that coordinates multiple machines).

[0062] The second communication device (communication equipment) 15 may include at least one or more front-ends (e.g., Relay Endpoints, REPs) 14a...14g. The front-ends 14a...14g may be, for example, optical front-ends (OFEs). In the case of OFEs, each OFE may include a phototransceiver, a photodiode, a transmitting diode, a light-emitting diode, an LED. In the case of RF, each front-end may include an RF transceiver. In the case of ultrasound, each front-end may include an ultrasound transceiver.

[0063] In an example, multiple front-ends 14a...14g may be part of a communications facility 15. The optical front-ends 14a...14g may be spatially distributed (e.g., at known locations) to transmit / receive communications over channels (e.g., optical channels) 18a...18g for transmitting and receiving in different parts of an environment. In an example, the front-ends 14a...14g may be fixed and / or have known locations.

[0064] The front-ends 14a...14g of the second communication device 15 may be connected to the coordinator 12 through a fronthaul 17. The fronthaul 17 may be configured with (or at least comprise) communication channels (e.g., 17a, 17b...17g) for enabling transmission between the front-ends 14a...14g and the coordinator 12. The fronthaul 17 may comprise at least one communication network. The fronthaul 17 may support a star topology. The fronthaul 17 may comprise multiple point-to-point connections. The fronthaul 17 may be wired (e.g., using metallic conductors) or cabled (for at least some connections) for connections with at least one front-end (in some examples, all connections with the front-ends are wired and / or cabled). In some examples, the fronthaul 17 is wireless (for connections with at least one front-end).

[0065] Reference numerals 18a...18g refer to optical channels (or more generally, wireless channels) between the optical front-ends 14a...14g and the first devices 16' and 16". The first devices are also referred to as first device devices, user equipment (UE), endpoint (EP) mobile devices, or communication devices. As can be seen, multiple front-ends may transmit (simultaneously) to the same first device. For example, FIG. 1 shows that front-ends 14a, 14b, 14c communicate with a first device 16' over channels 18a, 18b, 18c, respectively, while front-ends 14e, 14f, 14g communicate with another first device 16" over channels 18e, 18f, 18g, respectively.

[0066] As will be explained in more detail later, communications are considered herein to be defined in superframes (e.g., each superframe occupies a period of time, e.g., such that the end of a superframe ideally coincides with the beginning of the immediately following superframe, e.g., without superframe overlap). FIG. 2 shows superframe 1 and superframe 2. Each superframe may be divided into a series of slots (e.g., each slot occupies a period of time, e.g., such that the end of a slot ideally coincides with the beginning of the immediately following slot, e.g., without slot overlap). Each superframe may be understood as comprising a series of mutually adjacent slots (e.g., a superframe may be composed of an integer number of slots). All slots may be understood to have the same time length (although it may be possible for different superframes to have different time lengths), and the time length of the slots is generally known by both the first communication device 16', 16" and the second communication device 15. On the other hand, it may be the case that different superframes have different lengths (and, for example, the length of each superframe may be signaled, for example, by indicating how many "synch slots" there are in each superframe, for example in the "synch slots" field of the synchronization element, also called "synch element", see below). A number of slots form a slice (for example, each slice occupies a certain period of time, for example, without slice overlap, such that, for example, the end of a slice ideally coincides with the beginning of the immediately following slice). Each superframe may be understood as comprising a series of mutually adjacent slices (for example, a superframe may be composed of an integer number of slices). Different slices may have different lengths in terms of number of slots, and this information may be signaled.In the example (e.g., of FIG. 2), each slice (also called a "block") may be assigned to a particular device (e.g., one of 12, 15, 16', 16") or to a particular application (e.g., to upper layer application 902 as shown in FIG. 9), where a particular application is running on a particular device (e.g., one of 12, 15, 16', 16"). Some slices may not be used. The definition of a slice (e.g., identified by its slot, e.g., by the first slot of each slice) may be defined by scheduling and may be signaled, for example, in a GTS descriptor element (see FIG. 8 and related discussion), which may be part of the scheduling information 915. Thus, a superframe may be considered to be composed of a number of slices (e.g., defined by scheduling), and each slice may be considered to be further divided into a series of slots (e.g., slots of equal length). FIG. 2 does not show the slots, but shows the slices assigned to a particular allowed communication. The allowed communication is in the GTS (granted time slice). FIG. 2 shows that blocks 82a...82h are assigned to application traffic A and slices 83a, 83b, 83c are assigned to application traffic B. This is here for the purposes of this specification, which is the material here for defining whether application traffic A and application traffic B are in the uplink (e.g., from the first equipment device 16' or 16" to the coordinator 12) or not (from the coordinator device 16 to the first equipment device 16' or 16"). For the purposes of describing the technique here, in some examples, it is not important whether synchronization is performed in the granted time slot (GTS) (or granted time slice) or in the random time slot (RTS) (or random time slice).The GTS (or granted time slices) are defined by a scheduler (e.g., 910, see below), whereas the RTS (or random time slices) are sent in non-predefined time slices (e.g., according to event driven access). In an example, the RTS may be scheduled by the scheduler 910, but transmissions of multiple devices (e.g., 16', 16", 15) may occur in the RTS. In contrast, only a single device may transmit in the GTS (either the coordinator or the mobile device). In FIG. 2, slices 81a and 81b are occupied by synchronization information in the downlink (e.g., from the coordinator 12 to the first apparatus devices 16' and 16"). It will be explained later that the synchronization information (81a, 81b) may take the form of so-called "synchronization elements". The synchronization information 81a and 81b may include timing information (also called "synchronization slot" or "synchronization slot field", e.g., indicating in which slot of a superframe the current synchronization information 81a or 81b starts). The "synchronization slot field" thus provides information regarding when the superframe begins (e.g., by informing which slot of the superframe this synchronization information 81a or 81b starts in). The synchronization element thus informs the first device 16' or 16" as to which slot of the superframe (starting from slot 0) the frame containing the synchronization element will be transmitted in (e.g., the Nth slot). The first device 16' or 16" can then calculate back to the beginning of the superframe (N slots before the slot in which the frame starts).

[0067] For example, synchronization element 81a may provide information regarding the timing when superframe 1 began, and similar information may be provided by synchronization element 81b.

[0068] An example of the synchronization elements 81a, 81b (synchronization information) is provided in Fig. 5, which shows, for example, that a superframe number (e.g., a progressive number identifying a particular superframe) is encoded in a particular data field (shown in this example as being encoded in two octets, but different bit lengths may be used (macNumSuperframeSlots)). The synchronization elements (synchronization information) 81a, 81b may include information regarding the number of total slots in the current superframe, also shown as being encoded in octets, but different bit lengths may be used as seen in Fig. 5 (macNumSuperframeSlots), and may include a "synchronization slot" ("synchronization slot field"). The synchronization slot ("synchronization slot field") may be an example of timing information (it may be understood that in some examples, the number of slots in a superframe and / or the superframe number may also be considered to be part of the timing information). The synchronization slots may be used by the communication devices 16' and 16" to synchronize their clocks to the clock of the coordinator 12. In effect, each of the first apparatus devices 16' and 16" can reduce the offset between its local clock and the time indicated by the synchronization slot field (or more generally, the timing information) in the synchronization element (or more generally, the synchronization information 81a and 81b). To give just one example, in the example timing information 81b, information indicating t1, i.e. the distance from the beginning of superframe 2 (e.g., the number of slots from the first slot of the superframe to the first slot of the synchronization information 81b), would be written.

[0069] In many of the examples, it is imagined that the synchronization elements (synchronization information) 81a, 81b are sent exactly at the beginning of the superframe (in which case the "sync slot field" may be written with a "0"). However, for generality, the location of the synchronization elements (synchronization information) 81a, 81b in the superframe may take different time positions.

[0070] It should be noted that the synchronization slot field may encode the distance in time of the synchronization element from a reference time. The reference time may be, for example, the first slot of the current superframe (this choice is for simplicity and also because the synchronization information 81a, 81b is often assumed to be transmitted in the first slot of a superframe, and a typical value of the "synchronization slot field" is usually expected to be "0"). The transmission of the synchronization information may, for example, provide the timing of the packet (for example, of the packet's preamble) that contains the synchronization information 81a, 81b. Mostly, in the example, the synchronization elements (synchronization information) 81a, 81b are assumed to be transmitted at the beginning of the superframe, and most often the synchronization slot field is occupied by a value that is 0. This does not occur in the example of FIG. 2, simply because, for generality, it was preferable to indicate a different time position. It can nevertheless be seen that the synchronization element 81b (synchronization information) provides an indication of t1, which may be a time distance from the beginning of the superframe 2 (t1 may be indicated, for example, as a number of slots from the first slot of the superframe to the slot corresponding to the beginning of the synchronization element 81b). FIG. 4 shows the synchronization elements 81a, 81b (synchronization information). Here, it can be seen that the synchronization elements (synchronization information) 81a, 81b may be encapsulated in a PPDU (Physical Protocol Data Unit) that includes a preamble, a physical header, and a PSDU that includes the synchronization element. As can be seen, the beginning of the synchronization slot (indicated with 41) is the progressive synchronization slot (from the first slot of the superframe) to which the synchronization slot field (timing information) of FIG. 5 points. Thus, the beginning of the synchronization slot 41 may be, for example, t1 in the case of 81b. By considering the synchronization slots submitted as in the case of FIG. 5 (and also, in some cases, the first devices 16' and 16" may synchronize them with the clock of the coordinator 12).

[0071] However, it should be noted that in some examples it may be preferred not to maintain a fixed position of the synchronization element (or more generally, the synchronization information). As explained above, the transmission of the synchronization information (synchronization elements) 81a, 81b may in principle cause a delay of important application transmissions (e.g. scheduled or unscheduled). For this reason, in some examples it may be preferred not to maintain a fixed position for the transmission of the synchronization element (e.g. not necessarily at the very first synchronization slot of the superframe), but in some cases it may be preferred to allow a movable and definable positioning within the superframe. For example, let us assume in FIG. 2 that the synchronization element 81b should be transmitted at time t0. In that case, there would be no possibility to transmit a communication for application traffic A indicated by 82e (e.g. payload data requested by a higher layer application, e.g. 902, see below). In case of an emergency of the communication 82e, the coordinator 12 may decide to delay the transmission of the synchronization element 81b, so that the synchronization element 81b is not transmitted at the moment t0 but at a subsequent moment t1. This is not a problem, since for synchronization purposes, instead of indicating instant t0, instant t1 is indicated in the synchronization slot field (as timing information) of the synchronization element 81b. The first communication devices 16' and 16" simply resynchronize by considering the time distance of the beginning of the synchronization slot 41 (indicated in the synchronization slot) relative to the beginning of the superframe 2 (when considered here as the reference time). For this reason, synchronization between the coordinator 12 and the first communication devices 16' and 16" is permitted, and flexibility is also achieved. That is, it is permitted to selectively move the time position of the synchronization element in a more appropriate time slice, thereby reducing the disturbance of the transmission of the emergency communication. For the purposes of this description, it is of little importance to establish whether the transmission 82e is in the uplink or in the downlink. The transmission 82e may be an emergency unscheduled transmission from the coordinator 12 to the communication devices 16' and 16", or it may be a scheduled transmission from one of the devices 16' and 16" to the coordinator 12.It is easily possible to see that synchronization can be maintained together without stalling a fixed slice for control information at the expense of higher priority communications.

[0072] overview This contribution aims to enable, for example, optical communications with real-time low-latency behavior, for example for time division multiple access (TDMA) based medium access. Since the previously fixed structure (for example as defined in WO 2020 / 053235 A1) with beacons, collision avoidance periods (CAPs) and collision-free periods (CFPs) is broken, there is a general concept of time slices (TSs) that are used to reserve resources for multiple purposes. Thus, control information required for network operation can be transmitted at any time within the TDMA superframe structure, allowing the scheduler (for example part of the coordinator) to perform application data transmissions at the requested time.

[0073] The present contribution applies to a network (e.g., 10) following a cooperative topology, i.e. a network consisting of (or, more generally, comprising) member devices (e.g., 16' and 16") and one coordinator device (e.g., 12). The coordinator is responsible for allocating channel time to itself and to the member devices to enable interference-free transmission.

[0074] This proposal provides deterministic transmission for the support of real-time data streams through its channel access mechanism. The configuration of data streams is outside the scope of this document and may require implementation specific interfaces. The coordinator supports registered streams by scheduling resources for transmission accordingly.

[0075] The TDMA-based technique with the proposed modifications provides flexible medium access schedules that allow support of isochronous traffic. The coordinator 12 and member devices 16' and 16" obtain characteristics of real-time application data streams through the interface. The information includes one or more of the following: periodicity of the application data stream, maximum tolerable delay, maximum tolerable delay variation, size of datagrams, maximum tolerable loss ratio of datagrams.

[0076] There are different protocols for providing this information to OWPAN devices (12, 16' and 16"). Furthermore, this information may be provided in an implementation specific manner.

[0077] TDMA-based / Scheduled Medium Access The optical network (OWPAN) 10 uses scheduled medium access. Scheduled medium access relies on special frames (e.g., synchronization elements 81a, 81b, e.g., part of the PPDU in FIG. 4) to synchronize devices. The coordinator 12 allocates channel time for different methods of channel access. Deterministic channel access is supported with guaranteed time slice (GTS) and random channel access is supported with random time slice (RTS).

[0078] NOTE – In some cases, the RTS may be used only for specific purposes, such as association and requesting additional channel time resources.

[0079] In TDMA, or scheduled channel access mode, channel time may be divided into superframes (as in FIG. 2), which are further divided into contiguous groups of one or more slots, called time slices, as shown in FIG.

[0080] A time slice may be unallocated, assigned to a device as a guaranteed time slice (GTS), or designated as a random time slice (RTS). Assigning time slices is performed by an implementation-specific scheduler that is part of the coordinator 12. The scheduler (as part of the coordinator 12) may assign time slices for transmission to the coordinator as well as to members 16' and 16".

[0081] During GTS, devices 16' and 16" may (or, in some examples, should) perform deterministic medium access according to rules. During RTS, devices 12, 16' and 16" may (or, in some examples, should) perform random medium access.

[0082] When maintaining OWPAN 10 with scheduled medium access, the coordinator 12 may (or, in some instances, should) send frames that include a Sync element (such as 81a, 81b).

[0083] A superframe consists of (or, more generally, comprises) a total of macNumSuperframeSlots superframe slots, where macNumSuperframeSlots is a variable determined by the OWPAN coordinator and advertised to devices in the Sync element.

[0084] The superframe slot having the number 0 may (or in some examples should) be the first slot in the superframe (this is not the example of FIG. 2 and may be harmless).

[0085] The technique uses an integer number of superframe slots to specify a duration within a superframe, for example the duration of a GTS or an RTS.

[0086] Each of these time slices in a superframe can be in one of the following states for the duration of the current superframe: · Unassigned: Devices do not have to (or in some instances should not) transmit in these slots. · Allocated as GTS: A time slice has been allocated to a device by the coordinator using the GTS descriptor element. The corresponding device 16' or 16" may (or in some instances should) transmit during the GTS. · Allocated as RTS: These slots were allocated as RTS by the coordinator 12 using the RTS Descriptor element. During the RTS, devices 16' and 16" may randomly access the channel via slotted ALOHA.

[0087] Device 12, 16' or 16" may (or, in some examples, should) refrain from transmitting in superframe slots not assigned to it. This applies in particular to devices 16' and 16", which are not permitted to transmit transmissions in slots not assigned to them. In some cases, coordinator 12 may transmit important transmissions (e.g., high-rank transmissions) in unassigned slots.

[0088] Synchronization of member devices (12, 16', 16") through coordinator 12 All members (e.g., 16' and 16") may (or, in some examples, should) synchronize with the coordinator's clock (e.g., the clock of coordinator 12) before starting transmission or reception. Sync elements (e.g., 81a, 81b) transmitted by coordinator 12 enable synchronization of members 16' and 16" to scheduled medium access by arrival time synchronization.

[0089] The coordinator 12 may (or, in some examples, should) maintain the value of macSuperframeNumber and increment it by 1 for each superframe that it starts. The macSuperframeNumber value wraps around to 0 (65535) after it reaches a maximum value (e.g., this is the number associated with 2 octets, although different bit lengths may contain different maximum values).

[0090] The coordinator 12 may (or in some examples should) transmit a frame (e.g., as shown in FIG. 4) including a Sync element (e.g., 81a, 81b) via each OFE (14a...14g) at a suitable time slice at an implementation-specific rate, but at least every aMacMinSyncInterval. The receiver address of the frame may (or in some examples should) be a broadcast address. The frame may (or in some examples should) include the current macSuperframeNumber, the number of slots included in the superframe (e.g., as shown in FIG. 5), and the number of the slot (e.g., t1 in FIG. 2 as shown in the sync slot as shown in FIG. 5) in which the frame including the Sync element (e.g., 81a, 81b) was transmitted. The coordinator may (or in some examples should) start transmitting the frame at the start of the superframe slot.

[0091] Upon receiving a Sync element (e.g., 81a, 81b), members 16' and 16" may (or, in some examples, should) set their macSuperframeNumber and macNumSuperframeSlots values ​​to the values ​​in the received Sync element. Additionally, members 16' and 16" may (or, in some examples, should) synchronize their clocks to the received Sync element 81a, 81b by reducing the offset between their local clocks and the time indicated by the Sync Slot field in the Sync element (e.g., to less than aPhyOfeSyncAccuracy).

[0092] If a Sync element 81a, 81b is not received for the duration of a superframe, devices 16' and 16" may (or, in some examples, should) assume that the value specified for macNumSuperframeSlots in the last received Sync element is still valid and increment macSuperframeNumber when the next expected superframe begins. Thus, the technique tolerates situations where synchronization elements 81a, 81b are never transmitted, thereby increasing reliability.

[0093] If a Sync element 81a, 81b is not received within aMacMinSyncInterval, devices 16' and 16" may (or, in some examples, should) continue to listen for the next Sync element in order to synchronize before attempting further transmissions. Devices 16' and 16" may be considered out of sync after more than 2 * aMacMinSyncInterval has elapsed without receipt of a Sync element.

[0094] Random Access in RTS RTS is a) Association Procedure b) GTS Request Procedure In may (or in some instances should) be used only for transmissions from the device to the coordinator.

[0095] A slotted Aloha scheme may be used for contention-based access in the RTS. Superframe slots in the RTS are grouped in so-called RANDOPS, each of which contains RANDOP Length superframe slots. The number of superframe slots per RANDOP determines the slot size of the slotted Aloha scheme and thus the effectiveness of collision avoidance. The value of RANDOP Length is advertised in the RANDOP Length field of the RTS Descriptor element.

[0096] RTS are signaled through RTS descriptor elements and sent from the coordinator to the members. For each received RTS descriptor element, the corresponding RTS may (or in some instances should) start in the superframe slot given in the RTS descriptor element and end after the number of slots given in the RTS Length field.

[0097] The number and duration of RTSs may be varied by the coordinator to allow for more or fewer random access transmissions in a superframe.

[0098] NOTE - The coordinator 12 should periodically transmit frames containing the RTS descriptor element to enable association and to prevent members 16' and 16" from unnoticed exhaustion of transmission resources.

[0099] A device may request additional resources during a GTS. However, when a device has no or insufficient GTS time allocated to perform a GTS request, the device may use an RTS to send a GTS Request element to the coordinator.

[0100] Scheduled Medium Access in GTS GTS allows channel access based on the principle of time division multiple access (TDMA).

[0101] Coordinator 12 may effect transmission to devices 16' and 16" at any point during the superframe except when the devices have an assigned time slice (half duplex).

[0102] When the coordinator 12 controls multiple spatially distributed OFEs 14a...14g, the coordinator 12 may allocate the same superframe slot in different GTS or RTS to multiple spatially separated devices 16' or 16" to enable spatial reuse of superframe slots within the OWPAN coverage area. The coordinator 12 should, in some examples, allocate the GTS and RTS in a manner such that transmissions in the RTS do not interfere with transmissions in the GTS.

[0103] All members 16' and 16" may (or, in some examples, should) synchronize with the coordinator's clock before they begin transmitting or receiving, regardless of whether they are associated or attempting to associate with the scheduled OWPAN 10. A frame (e.g., shown in FIG. 4) containing Sync elements 81a, 81b (e.g., shown in FIG. 6) enables synchronization of devices 16' and 16" in the scheduled OWPAN 10 by arrival time synchronization.

[0104] Members 16' and 16" may (or, in some examples, should) assume that the beginning of the preamble 41 of the PPDU carrying synchronization elements 81a, 81b corresponds to the start time of the synchronization slot specified in the synchronization element. Thus, the superframe starts a slot of the synchronization slot before the start of the preamble. All superframe slots, and therefore timing within the superframe, are relative to the calculated start of the superframe.

[0105] To prevent collisions between transmissions of different devices, there is a guard time between successive GTSs, the duration of which is calculated from the clock accuracy and rate of the synchronization element transmission as follows: MaxDrift = aClockAccuracy * SyncInterval where aClockAccuracy is a MAC constant and SyncInterval is the interval between synchronization element transmissions, and thus the periodicity of the synchronization event.

[0106] The regulator must be at least 2 * (MaxDrift + aPhyOfeSyncAccuracy) GTSs may (or, in some instances, should) be allocated subject to the constraint that the guard time between two subsequent GTSs is not orthogonal in space.

[0107] OWPAN / Network Announcement The coordinator 12 may (or, in some examples, should) start transmitting an Announcement element in a preferred time slice at least every aMaxAnnouncementPeriod.

[0108] The Announcement element may (or in some instances should) include the current values ​​of the OWPAN Name and OWPAN Name Length.

[0109] If multiple OFEs 14a...14g are used by the coordinator 12, a frame containing an Announcement element may (or, in some examples, should) be transmitted via all OFEs 14a...14g.

[0110] Before association is attempted in the RTS, devices 16' and 16" may (or in some examples should) wait to receive an Announcement element. Upon receiving the Announcement element, devices 16' and 16" may (or in some examples should) update their OWPAN name values ​​to the values ​​in the received Announcement element. Additionally, the devices may (or in some examples should) apply modified values ​​from any Attribute Change Request elements included in the same frame as the Announcement element. The values ​​included in the Announcement element are required for association with OWPAN 10.

[0111] Information Carrying Frames and Elements We assume that the optical communication system uses a frame format that starts with a preamble and a PHY header at the physical layer, followed by a second MAC layer header and a payload. The MAC header distinguishes the payload type, while the actual payload consists of (or, more generally, contains) one or more elements.

[0112] Synchronization elements The Sync element, or more generally, synchronization information 81a, 81b, is shown in FIG. 5 and is used to transmit synchronization information from the coordinator 12 to members 16′ and 16″ as part of the scheduled medium access defined in FIG. 6.

[0113] Superframe Number: The number of the current superframe in which the frame containing the synchronization element was transmitted.

[0114] Total Superframe Slots: The total number of slots contained in the current superframe.

[0115] Synchronization slot (or more generally, timing information): The slot in which the preamble of the frame that contained the Sync element was transmitted.

[0116] The example of Figure 5 has already been explained and its fields are rewritten here above.

[0117] Announcement element

[0118] The Announcement element shown in Figure 6 serves to announce OWPAN as part of the OWPAN maintenance procedure.

[0119] OWPAN Name Length: The length of the OWPAN Name field that follows, in octets.

[0120] OWPAN Name: A human readable network name, encoded as a UTF-8 string. This string does not have to (and in some instances should not) contain null bytes in any location.

[0121] NOTE - OWPAN IDs may differ bit by bit but appear the same to humans due to possible homoglyphs in the UTF-8 encoding.

[0122] RTS Descriptor Element The RTS descriptor element shown in FIG. 7 describes a single RTS allocation in the beacon-enabled channel access mode.

[0123] RTS Start Slot: This field specifies the first slot of the allocated RTS.

[0124] RTS Length: This field specifies the duration of the RTS in superframe slots.

[0125] RANDOP Length: This field specifies the number of slots in the RANDOP during the described RTS.

[0126] Validity Information: This field indicates how the validity information of the GTS is signaled. See below on how to interpret the included values.

[0127] Valid Immediately: If this field is set to 1, GTS becomes valid in the same superframe in which the GTS descriptor element was received. Otherwise, GTS becomes valid in the next following superframe. This field is present only if Validity Information is equal to 0.

[0128] Valid Superframe: This field specifies the superframe in which the GTS is valid. This field is present only if Validity Information is equal to 1.

[0129] GTS Start Slot: This field specifies the first slot of the allocated GTS.

[0130] GTS Length: This field specifies the duration of the GTS in superframe slots.

[0131] constant The constant aMaxAnnouncementPeriod defines that announcements must be sent at least every second.

[0132] It is defined that aPhyOfeSyncAccuracy defines the maximum deviation of the actual transmission time at an optical emitter from the nominal transmission time intended by the MAC.

[0133] The constant aMacMinSyncInterval, which has a value of 1 s, defines the minimum rate of synchronization element transmission per OFE.

[0134] Other Aspects The second communication device 15 [e.g. a master communication device, a communication facility, a base station, or a coordinator, or a scheduler] may transmit a control signal. [The control signal may include scheduling information and / or synchronization information (e.g. including timing information)] [The scheduling information may include a GTS descriptor element and / or an RTS descriptor element] [Multiple control signals may be transmitted in at least one packet and may be distinguished by various techniques, for example by using a different preamble or anyway a different unique sequence for each control signal].

[0135] At least some of the control signals may be transmitted in GTSs exclusively assigned to the second communication device 15 [e.g., master communication device, communication equipment, base station, or coordinator, or scheduler]. However, in examples, the control signals (and in particular the synchronization information 81a, 81b) may be event-driven (e.g., transmitted only when necessary, without necessarily scheduling it). (e.g., the control signals may be transmitted only in different channels that will be used to transmit at least some control signals and / or in at least one RTS, and in some examples, the other communication devices may always remain waiting to receive transmissions from the communication devices during the unassigned time slots, and thus the communication devices can occupy the unassigned slots to transmit at least some control signals in an event-driven manner, without necessarily scheduling their event-driven control signals).

[0136] The control signals may be transmitted, for example, in an event-driven manner, when application frames should be urgently transmitted and / or received. For example, in one example according to FIG. 2, data transmissions 82a-82h (e.g., traffic A assigned to a first communication device 16′) and data transmissions 83a-83c (e.g., traffic B assigned to another first communication device 16″) are scheduled, but the control signals 81a and 81b are event-driven and may be transmitted in slots not assigned to any transmission (thus the second communication device 15 has the privilege to transmit the control signals 81a and 81b in those unassigned slots). In particular, the scheduling in superframe 2 is not required for the control signals transmitted in superframe 1. The control signal 81b may be defined by the control signal 81a that is encoded in the data transmission 82e. Internally, the second communication device 15 [e.g., a master communication device, a communication facility, a base station, or a coordinator, or a scheduler] may predict to transmit the control signal 81b in the time slot t0. However, considering the high rank urgency of the data transmission 82e, the data transmission 82e may take precedence and the control signal 81b may be delayed to the time slot t1. If the control signal 81b also contains a timing element, when this is instantiated by the data value "SynchSlot", its value is updated (e.g., instead of t0, there is t1 encoded).

[0137] Note that Figure 2 also applies to the case where control signal 81b is actually scheduled to be transmitted in slot t0. In this case, the shift applies in either case. If it had only sent in the scheduling information in control signal 81a, then the slots starting at t0 would have been allocated for traffic A and for transmission 82e.

[0138] In the above example, the second communication device 15 [e.g., a master communication device, a communication facility, a base station, or a coordinator, or a scheduler] may be (or may include) a connected higher layer application. The higher layer application may define the characteristics of the real-time application data stream through the interface. This information may include one or more of the following: periodicity of the application data stream, maximum tolerable delay, maximum tolerable delay variation, size of the datagrams, maximum tolerable loss ratio of the datagrams. For example, in the example of FIG. 2, the maximum tolerable delay of traffic A (in particular transmission 82e) may require rescheduling of transmission 82e to timeslot t0, thereby causing a shift of the control signal 81b to timeslot t1.

[0139] (In some examples, when a transmission is "at t0," it means, for example, "the transmission starts at t0.")

[0140] An example of communication in the adjuster 12 An example of communication in the coordinator 12 (or more generally in a base station 15 or second device communication facility) is shown in FIG. 9. Here, an upper layer application 902 is shown exchanging data with the first devices 16′ and 16″ through the OFEs 14a, ..., 14g (as shown in FIG. 1). In particular, data A (traffic A) transmitted in some specific slices (GTS) 82a, ..., 82h in the downlink and other data B (traffic B) are received in GTS slices 83a-83c according to the example of FIG. 2. A scheduler 910 (allocating different slices to different traffic A and B and / or allocating different slices, i.e. consecutive slots, to different devices) exchanges control data 913 with the upper layer application 902. Thus, scheduling information 915 can be provided to the first devices 16′, 16″ (e.g., which slices are to be allocated to the devices). , 82h)。 A synchronization information generator 920 (generating synchronization elements 81a, 81b, or more generally, signal information or even messages of FIG. 4 including synchronization elements 81a, 81b) is shown at 920. The synchronization information 920 may exchange control information with the scheduler 910. FIG. 9 shows a queue 930 in which data (traffic A) and synchronization information 81a, 81b of slices 82a, ..., 82h are received from the upper layer application 902 and the synchronization information generator 920, respectively. From the queue 930, the data and synchronization information 81a, 81b of slices 82a, ..., 82h may be transmitted to the first device 16', 16" through the front ends 14a, ..., 14g. Feedback information 931 may be received by the synchronization information generator 920 from the queue 930. In this example, considering the example of Fig. 9, each superframe is scheduled (e.g., as shown in Fig. 2), which means that synchronization elements 81a are generated by a synchronization information generator 920, encapsulated and provided to a queue 930, and transmitted through OFEs 14a...14g according to the timing defined by a scheduler 910.In superframe 2 of FIG. 2, the synchronization information generator 920 refrains from transmitting synchronization element 81b at instant t0 to allow for the transmission of urgent data (traffic A) in time slot 82e. Nevertheless, synchronization information 81b is transmitted at instant t1. However, as explained above, in the timing information (e.g., "synchronization slot field") of synchronization element 81b, an indication is provided informing about instant t1 (but no information about instant t0 is provided). Note that this example is only one of the possibilities. In particular, although feedback 931 is shown as being provided from queue 930 to synchronization information generator 920, this may not be the case. That is, scheduler 930 may decide to schedule (including schedule synchronization element 81b) without having to have any feedback 931 from queue 930 (but having urgency information from upper layer application 902, for example). In particular, the transmission of the synchronization elements 81a, 81b may be performed without any problems in the downlink, in which case it is the scheduler 910 that needs to schedule the GTS for which the data is received in the GTS slice 82e. The synchronization information generator 920 and the scheduler 910 may be connected (914), so that the schedule may dynamically perform, for example, a rescheduling taking into account the feedback 931.

[0141] Basically, it is not crucial here whether the data to be transmitted in slot t0 is in the uplink or downlink, or scheduled or unscheduled data. That is, it is important that the synchronization information 81b is transmitted at a time that can be selectively determined by the coordinator 12, but still allows synchronization of the second devices 16' and 16", increasing flexibility (but not sacrificing reliability).

[0142] The upper layer application 902 may provide the second communication device 15 with information (e.g. through an interface) about the characteristics of the real-time application data stream. The information about the characteristics of the real-time application data stream may include one or more of the periodicities of the payload data of the application data stream. Thus, the coordinator 12 knows how many times per superframe the payload data should be sent and / or received. The information about the characteristics of the real-time application data stream may include the maximum tolerable delay (e.g. maximum tolerable delay variation) of the transmission of the payload data of the application data stream. Thus, the coordinator 12 knows whether it is allowed to delay the transmission of the payload data or whether it is preferable to delay another data. That is, for example, in FIG. 2, perhaps the payload data (traffic A) 82e cannot be delayed (e.g. due to the maximum tolerable delay for the transmission of the payload data) and therefore it is preferable to delay the transmission of the synchronization element (synchronization information) 81b. In a variant, instead of the maximum tolerable delay there may be a maximum tolerable loss ratio [e.g. of datagrams]. The information regarding the characteristics of the real-time application data stream may include (or may provide information that allows for understanding) how many times per superframe the payload data should be sent and / or received. Accordingly, the scheduler 910 may generate a schedule to allow for the transmission of the particular payload data.

[0143] In some examples, if information regarding the characteristics of a real-time application data stream requires a certain maximum latency for transmission and / or reception of a certain transmission (e.g. from and / or to the UE), then a time slot that is not scheduled for a certain different communication device (e.g., a UE) may be given to a different first communication device (e.g., by quickly rescheduling on the fly) and / or other transmissions (e.g., control signals) from the communication device may be shifted towards subsequent time slots. [This may be done, for example, if a higher layer application designates some payload transmissions as having a high rank of urgency].

[0144] Thus, the operation of the scheduler 910 may be considered known. However, in some cases, it may be possible to define the scheduling based on some feedback. For example, In case of relatively higher traffic congestion, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower traffic congestion, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. It is possible to operate the scheduling in this way.

[0145] For example, traffic congestion may be measured by, for example, measuring round trip latency times and / or error rates.

[0146] Additionally or alternatively, In case of relatively higher rank transmissions and / or receptions, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower rank transmissions and / or receptions, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. Such that the urgency of transmission may be ranked and / or the reception is ranked according to the urgency rank.

[0147] An example of a first communication device 16', 16" FIG. 10 illustrates an example of a first communication device 16′ or 16″ of FIG. 1. As can be seen, the first communication device 16′, 16″ may include an optical (or more generally, wireless) transmitter / receiver 25. The wireless (e.g., optical) transmitter / receiver 25 may be optically connected (or more generally, wirelessly connected) to the (e.g., optical) front-ends 14a...14g (e.g., through optical connections or, more generally, wireless connections 18a...18g). The transmitter / receiver 25 may be internally connected (e.g., through lines 25′, e.g., wired lines) to the upper layer application 927. The upper layer application 927 may thus exchange payload data with the upper layer application 902 of the second device 15 (and in particular the coordinator 12) through the network 10 (e.g., OWPAN). FIG. 10 shows that an internal clock 27 is present in the first communication device 16', 16". For example, it is possible to synchronize the optical transmitter / receiver 25 through a clock signal 27'. Basically, the clock 27 can define the time length of each slot so that the scheduled transmission / reception of the transmitter / receiver 25 follows the synchronism given by the clock signal 27'. The internal clock 27 can in turn be synchronized with the clock of the coordinator 12 (second communication device 15) through a synchronization control 25''. The synchronization control 25'' can be output, for example, by the synchronizer 25. The synchronizer 25 can receive synchronization information (synchronization elements) 81a, 81b from the coordinator 12 (second communication device 15).

[0148] The synchronizer 25 may, as explained above, count the number of slots between the current reference time (e.g., the start of the superframe) and the start of the synchronization element (synchronization information) (e.g., the first slot of the preamble) and compare the counted number of slots with the number coded in the "synchronization slot field" (timing information). Taking into account the comparison, the synchronizer 25 may calculate the drift (offset) and compensate for the drift (offset) by adjusting the timing to the value written in the "synchronization slot field" (timing information). As explained above, the current reference time is often imagined to be the moment when the superframe starts, i.e., the first slot of the superframe. (The synchronizer 25 may update its knowledge of the time by controlling the clock 27 through the control 25'').

[0149] It should be noted that synchronization in the first communication device 16', 16" may be performed by evaluating the time distance between the encoded timing information and the measured timing reference (e.g., reference time) from the timing information (e.g., "synchronization slot field"). In case of a drift (offset) between the encoded timing information and the measured timing reference (e.g., reference time), it is possible for the communication device 16', 16" to adjust its internal clock to the encoded timing information.

[0150] Example for second communication device 15 (coordinator 12) In the above examples (e.g., of Figs. 1 and 9), a communication device 15 (coordinator 12) [e.g., communication equipment, base station, coordinator, scheduler, etc.] [e.g., for wireless communication, e.g., optical or RF communication] is disclosed, the communication device is configured to transmit and / or receive a plurality of packets [e.g., in a superframe] using a scheduling [e.g., defined by (individual) allocation of slots (or slices which may include a plurality of slots) in the superframe to different communication devices (e.g., designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g., designated as "RTS")] relative to a reference time [e.g., the beginning of a superframe, e.g., the first slot of the superframe, the reference may be periodic but may alternatively vary, nevertheless the reference time may be updated for new superframes], the communication device is configured to transmit synchronization information (e.g., having variable timing relative to a reference time) (e.g., the synchronization information may be transmitted with different timing (e.g., delays) relative to the reference time for different superframes); The communications device is configured to include within the synchronization information [e.g., within a synchronization element] timing information [e.g., "sync slot" information, e.g., information on which slot of a superframe a frame containing synchronization information starts in] that defines [and / or describes] the timing of transmission of the synchronization information relative to [e.g., compared to] a reference time [e.g., relative to the first slot of a current superframe] [e.g., relative to the first slot of a current superframe] [e.g., the timing of the preamble of a packet containing synchronization information].

[0151] The second communication device 15 (or the coordinator 12) may be configured to include in the timing information a time distance (e.g., in timeslots) from the transmission of the synchronization information (e.g., the timing of the preamble of a packet containing the synchronization information) and a reference time.

[0152] The second communication device 15 (or the coordinator 12) may be configured to include timing information, information regarding the time distance from the reference time to the next timing reference (eg "total superframe slots").

[0153] The second communication device 15 (or the coordinator 12) may be configured to provide scheduling information to the different communication devices (eg UEs) that allocates exclusive time slots to each of the different communication devices.

[0154] The second communication device 15 (or the coordinator 12) may be configured to provide to a different communication device [e.g. a UE] scheduling information allocating to the communication device exclusive time slots [e.g. a plurality of slots, e.g. one slice including a plurality of consecutive slots] for the transmission of at least some control signals [the control signals include the scheduling information, the synchronization information (including timing information)] [the scheduling information may include a GTS descriptor element and / or an RTS descriptor element] [the plurality of control signals may be transmitted in at least one packet and may be differentiated by various techniques, e.g. by using a different preamble or in any case a different unique sequence for each control signal] [for example, in some examples the transmission of a control signal may be delayed, e.g. like the control signal 81b in FIG. 2 being shifted from t0 to t1, taking into account the need to transmit or receive payload data, which may be done if necessary to address requirements set by a higher layer application].

[0155] The second communication device 15 (or the coordinator 12) may be configured to further transmit at least some control signals in an event-driven manner (e.g., in a different channel and / or in a time slot only allowed for transmitting at least some control signals and / or in at least one RTS; in some examples, the first communication device 16′, 16″ may remain waiting to receive a transmission from the second communication device 15 during all unallocated time slots, and thus the second communication device 15 may occupy the unallocated slots to transmit at least some control signals in an event-driven manner, without necessarily scheduling those event-driven control signals). [In the example of FIG. 2, the control signal 81b may be delayed (shifted towards a later time), which in some examples may be delayed until the new time slot now occupied by the control signal 81b is reached. was not assigned to any of the other communication devices 15, 16', 16", it does not necessarily require that scheduling be defined and provided to the other different communication apparatuses.][The control signal may include scheduling information, synchronization information (including timing information).][The scheduling information may include a GTS and / or an RTS descriptor element.][Multiple control signals may be transmitted in at least one packet and may be differentiated by various techniques, for example by using a different preamble or in any case a different unique sequence for each control signal.][For example, in some examples the transmission of an event-driven control signal may be delayed, for example the control signal 81b in FIG. 2 being shifted from t0 to t1, taking into account the need to transmit or receive payload data, which may be done for example if necessary to address requirements set by a higher layer application.]

[0156] The second communication device 15 or the coordinator 12 may be configured to delay the transmission of the control signal (81b) [whether scheduled or even-driven] [e.g. from t0 to t1] when a higher layer application requires the transmission and / or reception of a transmission [e.g. a payload frame from or to a UE, a different communication device] [thus, for example, the communication device may delay the transmission of the control signal 81b towards, for example, a first next slice (group of consecutive time slots) that is free (e.g. not assigned to any of the other different communication devices and / or not used at all)].

[0157] The second communication device 15 or the coordinator 12 may be such that the control signal includes (eg, has encoded therein) scheduling information for a subsequent transmission (eg, for a subsequent superframe).

[0158] The second communication device 15 or coordinator 12 may be such that the control signal includes (eg, has encoded therein) synchronization information for a subsequent transmission (eg, for a subsequent superframe).

[0159] The second communication device 15 or the coordinator 12 may be such that the control signal includes (e.g. has encoded therein) the announcement information (e.g. encoded information, human readable information therein, e.g. encoded in a UTF-8 string, ASCII code, etc.).

[0160] The second communication device 15 or the coordinator 12 may be such that the control signal includes (e.g. has encoded therein) random access timing information (e.g. being or including an RTS descriptor element) providing information about which slots (e.g. relative to a reference time) are grant-free.

[0161] The second communication device 15 or the coordinator 12 may be such that the control signal includes (e.g. has encoded therein) granted access timing information (e.g. being or including a GTS descriptor element) providing information about time slots (e.g. relative to a reference time) that are grant-free.

[0162] The second communication device 15 or the coordinator 12 may be configured to define scheduling information (eg, for future transmissions, eg, after a future time reference) by taking traffic into account.

[0163] The second communication device 15 or the coordinator 12 In case of relatively higher traffic congestion, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower traffic congestion, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. By doing so, scheduling information may be defined [eg, for a future transmission, eg, after a future time reference].

[0164] The second communication device 15 (or the coordinator 12) ranks the urgency of transmission and / or reception according to the urgency rank, and the communication device: In case of relatively higher rank transmissions and / or receptions, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of the different communication devices; and / or In the case of relatively lower rank transmissions and / or receptions, increasing the amount of time slots for transmission of control signals and / or decreasing the amount of granted time slots assigned to at least one of the different communication devices. It is configured as follows.

[0165] The second communication device 15 or the coordinator 12 may be configured to define scheduling by recovering time slots for [partial or complete] transmission of control signals when a threshold condition is reached [e.g. when it is no longer possible to refrain from transmitting control signals].

[0166] The second communication device 15 or the coordinator 12 may further comprise multiple front-ends (eg relays) configured to simultaneously transmit and / or receive different packets through the different front-ends.

[0167] The second communication device 15 or the coordinator 12 may be configured to selectively simultaneously transmit synchronization information [or more generally, different control signals] in different time slots to different front-ends [e.g., scheduling may be changed for different front-ends and the above conditions may apply per front-end, but at the same time other front-ends experience different conditions].

[0168] The second communication device 15 or the coordinator 12 may include or be connected to a higher layer application, and the communication device uses information about the characteristics of the real-time application data stream from the higher layer application (e.g. over an interface). [The information about the characteristics of the real-time application data stream may include one or more of the following: periodicity of the application data stream, maximum tolerable delay, maximum tolerable delay variation, size of the datagrams, maximum tolerable loss ratio of the datagrams].

[0169] The second communication device 15 or the coordinator 12 may be configured to use the information about the characteristics of the real-time application data stream in such a way that, for example, if the information about the characteristics of the real-time application data stream requires a certain maximum latency for the transmission and / or reception of a certain transmission (e.g. from and / or to the UE), a time slot that is not scheduled for a certain different communication device (e.g. UE) is given to a different communication device (e.g. by quickly rescheduling on the fly) and / or other transmissions (e.g. control signals) from the communication device are shifted towards subsequent time slots. [This may be done, for example, if a higher layer application designates some payload transmissions as having a high rank of urgency].

[0170] In the above examples (e.g. of Figures 1 and 9), a communication method [e.g. for wireless communication, e.g. optical or RF communication] [e.g. in a downlink from a communication facility, a base station, a coordinator, a scheduler, etc. to a user equipment, a mobile device, etc.] is shown, comprising the steps of transmitting and / or receiving a plurality of packets [e.g. in a superframe] using scheduling [e.g. defined by (individual) allocation of slots (or slices which may include multiple slots) in the superframe to different communication devices (e.g. designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g. designated as "RTS")] relative to a reference time [e.g. the beginning of a superframe, e.g. the first slot of the superframe, the reference may be periodic but alternatively may vary, nevertheless the reference time may be updated for new superframes], The method further includes transmitting synchronization information [e.g., having variable timing relative to a reference time] [e.g., the synchronization information may be transmitted with different timings (e.g., delays) relative to the reference time for different superframes], and transmitting the synchronization information includes including [e.g., encoding within a data field] timing information [e.g., "sync slot" information, e.g., information on which slot of a superframe a frame including synchronization information starts in] within the synchronization information [e.g., within a synchronization element] that defines [and / or describes] the timing of the transmission of the synchronization information [e.g., compared to] the reference time [e.g., relative to the first slot of a current superframe] [e.g., relative to the first slot of a current superframe] [e.g.

[0171] Also disclosed is a non-transitory storage unit that stores instructions, which when executed by the processor, cause the processor to: controlling the transmission and / or reception of a plurality of packets [e.g., during a superframe] using scheduling [e.g., defined by (individual) allocation of slots (or slices which may include a plurality of slots) in the superframe to different communication devices (e.g., designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g., designated as "RTS")] relative to a reference time [e.g., the beginning of a superframe, e.g., the first slot of the superframe, the reference may be periodic but alternatively may vary, nevertheless the reference time may be updated for new superframes]; controlling transmission of synchronization information (e.g., having variable timing relative to a reference time) and (e.g., for different superframes, the synchronization information may be transmitted with different timings (e.g., delays) relative to the reference time); The synchronization information includes including [e.g., encoded within a data field] timing information [e.g., "sync slot" information, e.g., information on which slot of a superframe a frame containing synchronization information starts in] within the synchronization information [e.g., within a synchronization element] that defines [and / or describes] the timing of transmission of the synchronization information [e.g., the timing of the preamble of a packet containing synchronization information] relative to [e.g., compared to] a reference time [e.g., relative to the first slot of the current superframe].

[0172] Embodiments Related to First Devices 16' and 16" In the above example, a first communication apparatus 16′ or 16 [e.g., for wireless communication, e.g., optical or RF communication] [e.g., user equipment UE, mobile device, etc.] is disclosed that is configured to receive synchronization information [e.g., in downlink and / or uplink] [e.g., having variable timing with respect to a reference time] [e.g., the synchronization information may be transmitted with different timing (e.g., delay) with respect to a reference time for different superframes]; the first communication device (16', 16") is configured to transmit and / or receive a plurality of packets [e.g. in a superframe] using a scheduling [e.g. defined by (individual) allocation of slots (or slices which may include a plurality of slots) in the superframe to different communication devices (e.g. designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g. designated as "RTS")] relative to a reference time [e.g. the beginning of a superframe, e.g. the first slot of the superframe, the reference may be periodic but alternatively may vary, nevertheless the reference time can be updated for new superframes] [e.g. transmission and / or reception are synchronized with the reference time], The first communication device (16', 16") is configured to evaluate timing information (e.g. "sync slot" information, e.g. information on in which slot of a superframe a frame containing synchronization information starts) contained in the synchronization information (e.g. encoded in the synchronization information) defining (and / or describing) the timing of the transmission of the synchronization information (e.g. the timing of the preamble of a packet containing synchronization information) relative to (e.g. compared to) a reference time (e.g. relative to the first slot of a current superframe) in order to perform synchronization (e.g. to synchronize its clock with the received synchronization information, e.g. by reducing the offset between its (local) clock and the time indication by the timing information in the synchronization information). Thus, the communication device obtains knowledge of which instant was the reference time, whereby it can subsequently transmit and / or receive the next frame using an updated timing relative to the reference time).

[0173] The first communication device 16′ or 16″ may be configured to evaluate from the timing information the time distance (e.g. in timeslots) from the transmission of the synchronization information (e.g. the timing of the preamble of the packet including the synchronization information) and the timing reference (e.g. by subtracting the time distance from the transmission of the synchronization information, thereby obtaining knowledge of which instant in time was the reference time, thereby subsequently transmitting and / or receiving the next frame using an updated timing relative to the reference time).

[0174] The first communication device 16' or 16" may be configured to evaluate from the timing information information relating to the time distance from one timing reference to the next timing reference (eg "total superframe slots").

[0175] A first communication device (e.g., 16') may be configured to receive scheduling information that assigns it an exclusive time slot, but different exclusive time slots are assigned to different first communication devices (e.g., 16"), such that the first communication device 16' transmits in the time slot assigned to it and refrains from transmitting in the time slots assigned to the different first communication devices 16" [and / or some unused time slots that may be used, e.g., by the master, e.g., in case of an emergency].

[0176] The first communication device 16' or 16" may be configured to receive scheduling information that allocates an exclusive time slot [e.g., a plurality of slots, e.g., a slice including a plurality of consecutive slots] to the second communication device (e.g., a master communication device) 15 [or a communication facility, a base station, or a coordinator, or a scheduler] for transmission [e.g., in the downlink] of at least a portion of the control signal, so that the first communication device receives the control signal at least in the time slot allocated for transmission [e.g., in the downlink] of the control signal [the control signal includes the scheduling information, synchronization information (including timing information) [The scheduling information may include a GTS descriptor element and / or an RTS descriptor element] [Multiple control signals may be transmitted in at least one packet and may be differentiated by various techniques, e.g. by using a different preamble or anyway a different unique sequence for each control signal] [For example, in some examples the transmission of a control signal may be delayed, e.g. control signal 81b being shifted from t0 to t1 in FIG. 2, taking into account the need to transmit or receive payload data, which may be done, for example, if necessary to address requirements set by a higher layer application].

[0177] The first communication device 16' or 16" may be configured to receive at least some control signals in an event-driven manner (e.g., in different channels and / or in different time slots that are only allowed to be used for receiving at least some control signals and / or in at least one RTS; in some examples, the first communication device may remain waiting to receive a transmission from the master communication device 15 (or the communication facility, base station, or coordinator, or scheduler, or the second communication device) during the unassigned time slots, and thus the master communication device 15 (or the communication facility, base station, or coordinator, or scheduler, or the second communication device) can occupy the unassigned slots to transmit at least some control signals in an event-driven manner without necessarily scheduling those event-driven control signals) [in the example of FIG. 2, the control signal 81b may be delayed (shifted towards a later time)]. 2 , which may be the case, but in some examples this does not necessarily require that scheduling be defined and provided to the other different communication devices, since the new time slot now occupied by the control signal 81b was not assigned to any of the other communication devices 15, 16′, 16″, etc.][The control signal may include scheduling information, synchronization information (including timing information)][The scheduling information may include a GTS and / or an RTS descriptor element][Multiple control signals may be transmitted in at least one packet and may be differentiated by various techniques, for example by using a different preamble or in any case a different unique sequence for each control signal][For example, in some examples the transmission of a control signal may be delayed, for example the control signal 81b being shifted from t0 to t1 in FIG. 2 , for example taking into account the need to transmit or receive payload data, which may be done if necessary to address requirements set by a higher layer application].

[0178] The first communication device 16' or 16" may be such that the control signal includes (eg, has encoded therein) scheduling information for a subsequent transmission.

[0179] The first communication device 16' or 16" may have the control signal include (eg, encode therein) synchronization information for subsequent transmissions.

[0180] The first communication device 16' or 16" may be such that the control signal includes (e.g., has encoded therein) announcement information (e.g., encoded information, human readable information therein, e.g., encoded in a UTF-8 string, ASCII code, etc.).

[0181] The second communication device 16' or 16" may be such that the control signal includes (e.g., has encoded therein) random access timing information (e.g., being or including an RTS descriptor element) providing information regarding which slots (e.g., relating to a timing reference or reference time) are grant-free.

[0182] The first communication device 16' or 16" may include (e.g., have encoded therein) granted access timing information (e.g., being or including a GTS descriptor element) that provides information about which time slots (e.g., relative to a reference time) the control signal is grant-free.

[0183] The first communication device 16' or 16" may be such that time slots not scheduled for the first communication device are given to a different communication device (e.g., by quickly rescheduling on the fly) if information regarding the characteristics of the real-time application data stream defined by the higher layer application requires a certain maximum latency for the transmission and / or reception of a particular transmission [other transmissions (e.g. control signals) from the master communication device 15 may be shifted towards subsequent time slots] [this may be done, for example, if the higher layer application designates some payload transmissions as having a high rank of urgency].

[0184] In the example disclosed above, receiving synchronization information (e.g., having variable timing relative to a reference time); and (e.g., the synchronization information may be transmitted for different superframes with different timings (e.g., delays) relative to the reference time); transmitting and / or receiving a plurality of packets (e.g., in a superframe) using scheduling (e.g., defined by (individual) allocation of slots (or slices which may include multiple slots) in the superframe to different communication devices (e.g., designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g., designated as "RTS")) relative to a reference time (e.g., the beginning of a superframe, e.g., the first slot of the superframe; the reference may be periodic, but alternatively may vary, nevertheless the reference time can be updated for new superframes); (e.g., transmission and / or reception are synchronized with the reference time); evaluating timing information (e.g. "sync slot" information, e.g. information on in which slot of a superframe a frame containing the synchronization information starts) contained in the synchronization information (e.g. encoded in the synchronization information) defining (and / or describing) the timing of the transmission of the synchronization information (e.g. the timing of the preamble of a packet containing the synchronization information) relative to (e.g. compared to) a reference time (e.g. relative to the first slot of a current superframe) to perform the synchronization (e.g. to synchronize its clock with the received synchronization information, e.g. by reducing the offset between its (local) clock and the time indication by the timing information in the synchronization information); and (e.g. the communications device thus obtains knowledge of which instant in time was the reference time and is thereby able to subsequently transmit and / or receive the next frame using updated timing relative to the reference time). A communication method, [e.g., for wireless communication, e.g., optical communication or RF communication] [e.g., in a user equipment UE, mobile device, etc.] comprising:

[0185] Also described is a non-transitory storage unit that stores instructions, which when executed by the processor, cause the processor to: Controlling reception of synchronization information (e.g., having variable timing relative to a reference time) (e.g., synchronization information may be transmitted for different superframes with different timings (e.g., delays) relative to the reference time); controlling the transmission and / or reception of a plurality of packets [e.g., during a superframe] using scheduling [e.g., defined by (individual) allocation of slots (or slices which may include a plurality of slots) in the superframe to different communication devices (e.g., designated as "GTS") and / or by allocation of slots (or slices) to random transmissions (e.g., designated as "RTS")] relative to a reference time [e.g., the beginning of a superframe, e.g., the first slot of the superframe; the reference may be periodic, but alternatively may vary, nevertheless the reference time can be updated for new superframes] [e.g., transmission and / or reception are synchronized with the reference time]; and To achieve synchronization [e.g. to synchronize its clock with the received synchronization information, e.g. by reducing the offset between its (local) clock and the time indication by the timing information in the synchronization information], the communication device evaluates timing information [e.g. "synchronization slot" information, e.g. information on in which slot of a superframe a frame containing the synchronization information starts] contained [e.g. encoded] in the synchronization information and defining [and / or describing] the timing of the transmission of the synchronization information [e.g. compared to] a reference time [e.g. relative to the first slot of the current superframe] [e.g. thus the communication device obtains knowledge of which instant in time was the reference time and is thereby able to subsequently transmit and / or receive the next frame using updated timing relative to the reference time]. Have them carry out the procedure.

[0186] Further examples are defined by (and are within) the enclosed claims.

[0187] It is to be noted that any example defined by the claims can be supplemented by any of the details (features and functions) described in the following sections.

[0188] Also, the examples described in the following sections may be used individually or may be supplemented by any of the features in the other sections or by any of the features included in the claims.

[0189] It should also be noted that the individual aspects described herein may be used individually or in combination, and thus details may be added to each of the individual aspects without adding details to another of the aspects.

[0190] It should also be noted that the present disclosure explicitly or implicitly describes features of mobile communication devices, receivers, and mobile communication systems. Thus, any of the features described herein may be used in the context of a mobile communication device, and in the context of a mobile communication system (e.g., comprising a satellite, a mobile communication network, etc.).

[0191] Moreover, the features and functions disclosed herein with respect to the method may also be used in the apparatus. Moreover, any feature and function disclosed herein with respect to the apparatus may also be used in the corresponding method. In other words, the method disclosed herein may be complemented by any of the features and functions described with respect to the apparatus.

[0192] Also, any of the features and functions described herein may be implemented in hardware or in software, or using a combination of hardware and software, as described above.

[0193] Depending on the particular implementation requirements, the examples may be implemented in hardware. The implementation may be implemented using a digital storage medium, such as a floppy disk, a digital versatile disk (DVD), a Blu-ray disk, a compact disk (CD), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory, that stores electronically readable control signals and cooperates (or is capable of cooperating) with a programmable computer system to implement the respective methods. Thus, the digital storage medium may be computer-readable.

[0194] In general, the examples may be implemented as a computer program product having program instructions operable to perform one of the methods when the computer program product runs on a computer. The program instructions may be stored on a machine-readable medium, for example.

[0195] Other examples include the computer program for performing one of the methods described herein, stored on a machine-readable carrier. In other words, therefore, an example of a method is a computer program having program instructions for performing one of the methods described herein, when the computer program runs on a computer.

[0196] A further example of a method is therefore a data carrier medium (or digital storage medium, or computer readable medium) comprising a computer program for performing one of the methods described herein and having recorded thereon the computer program. The data carrier medium, digital storage medium, or recorded medium is tangible and / or non-transitory, rather than a signal, which is intangible and transitory.

[0197] Further examples include a processing unit, for example a computer, or a programmable logic device, that performs one of the methods described herein.

[0198] A further example comprises a computer having installed thereon the computer program for performing one of the methods described herein.

[0199] Further examples include an apparatus or system for transferring (e.g., electronically or optically) a computer program for performing one of the methods described herein to a receiver. The receiver may be, for example, a computer, a mobile device, a memory device, etc. The apparatus or system may, for example, comprise a file server for transferring the computer program to the receiver.

[0200] In some examples, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In some examples, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, the methods may be performed by any suitable hardware apparatus.

[0201] The examples described above are illustrative of the principles described above. It is understood that modifications and variations of the configurations and details described herein are obvious. It is therefore intended to be limited by the scope of the appended claims, and not by the specific details presented by the description and illustration of the examples herein.

[0202] The claims add embodiments and / or alternatives to the invention (eg, in brackets or parentheses and / or in alternatives or examples). [Explanation of symbols]

[0203] 10 Network, Optical Network (OWPAN), OWPAN 12 Regulators and devices 14a…14g front end, optical front end, OFE 15 Communication equipment, second communication equipment, base station, device, second equipment 16', 16" first device, first communication device, first device device, first device, communication device, device, member device, member 17 Front Hall 17a, 17b…17g communication channels 18a…18g channels, wireless connection 25 Optical transmitter / receiver, wireless transmitter / receiver, transmitter / receiver 25 Synchronizer 25' Line 25'' Synchronous control, control 27 Internal Clock, Clock 27' Clock signal 81a, 81b slice, synchronization information, synchronization element, Sync element, control signal 82a…82h Block, data transmission, slice (GTS), slice 82e Communication, transmission, data transmission, time slot, GTS slice 83a, 83b, 83c slices 902 Upper layer application, Upper layer application 910 Scheduler 913 Control Data 914 Connection 915 Scheduling Information 920 Synchronization information generator 927 Upper Layer Applications 930 Queue 931 Feedback information, feedback

Claims

1. A communication device (15), the communication device (15) is configured to transmit and / or receive a plurality of packets using a scheduling related to a reference time; the communication device (15) is configured to transmit synchronization information (81a, 81b); the communication device (15) is configured to include timing information in the synchronization information (81a, 81b) defining a timing of transmission of the synchronization information (81a, 81b) relative to the reference time, Communications equipment (15).

2. The communication device of claim 1 , configured to include in the timing information a time distance from the transmission of the synchronization information and the reference time.

3. 3. The communication device according to claim 1, configured to include in the timing information information on a time distance from the reference time to a next timing reference.

4. 4. A communication device according to any one of claims 1 to 3, arranged to provide different communication devices with scheduling information allocating exclusive time slots to each of said different communication devices.

5. 5. A communication device according to claim 1, configured to provide different communication devices with scheduling information allocating exclusive time slots to said communication devices for the transmission of at least some control signals.

6. 6. The communication device according to any one of claims 1 to 5, configured to further transmit at least some control signals in an event-driven manner.

7. The communication device according to claim 5 or 6, wherein the control signal includes at least the synchronization information.

8. A communications device according to any one of claims 5 to 7, configured to delay or advance the transmission of control signals when a higher layer application requires the sending and / or receiving of a transmission.

9. 9. A communication device according to claim 5, configured to: check if at least some slots are free according to said scheduling when an upper layer application requires the transmission and / or reception of a transmission of payload data, and accordingly delay or advance the transmission of said control signals in free slots within the same superframe, otherwise waiting for the next superframe.

10. 10. The communications device of claim 5, wherein the control signal includes scheduling information for a subsequent transmission.

11. 11. The communications device of claim 5, wherein the control signal includes the synchronization information for a subsequent transmission.

12. The communication device according to claim 5 , wherein the control signal includes notification information.

13. 13. The communications device of claim 5, wherein the control signal includes random access timing information providing information about slots that are grant free.

14. 14. A communications device according to any one of claims 5 to 13, wherein the control signal includes granted access timing information providing information regarding time slots which are grant free.

15. 15. A communication device according to any one of claims 5 to 14, configured to define said scheduling information by considering traffic.

16. in case of relatively higher traffic congestion, reducing the amount of time slots for the transmission of control signals and / or increasing the amount of granted time slots assigned to at least one of said different communication devices; and / or 16. The communication device of claim 15, for defining the scheduling information by increasing an amount of the time slots for the transmission of control signals and / or decreasing an amount of the granted time slots assigned to at least one of the different communication devices in case of relatively lower traffic congestion.

17. The urgency of the transmission and / or reception is ranked according to an urgency rank, and the communication device: In case of a relatively higher rank of transmission and / or reception, reducing the amount of the time slots for the transmission of control signals and / or increasing the amount of the granted time slots assigned to at least one of the different communication devices; and / or In the case of a relatively lower rank of transmission and / or reception, increasing the amount of the time slots for the transmission of control signals and / or decreasing the amount of the granted time slots assigned to at least one of the different communication devices.

17. A communication device as claimed in claim 15 or 16, configured to:

18. 18. A communications device according to claim 15, 16 or 17, configured to define the scheduling by restoring the time slots for the transmission of the control signals if a threshold condition is reached.

19. 19. The communication device of claim 1, further comprising a plurality of front-ends configured to simultaneously transmit and / or receive different packets through different front-ends.

20. 20. The communications device of claim 19, configured to selectively simultaneously transmit synchronization information in different time slots to different front ends.

21. 21. A communications device according to any one of claims 1 to 20, comprising or connected to a higher layer application, the communications device using information about characteristics of real-time application data streams from the higher layer application.

22. 22. The communications device of claim 21, wherein the information regarding characteristics of a real-time application data stream includes one or more of the following: periodicity of the application data stream, maximum tolerable delay, maximum tolerable delay variation, maximum tolerable loss ratio of datagrams.

23. 23. The communications device according to claim 21 or 22, wherein the communications device is configured to use the information regarding the characteristics of a real-time application data stream in such a way that, for example, if the information regarding the characteristics of a real-time application data stream requires a particular maximum latency for transmission and / or reception of a particular transmission, a time slot that is not scheduled for a particular different communications device is given to the different communications device and / or other transmissions from the communications device are shifted towards subsequent time slots.

24. 24. A communications device according to any one of claims 1 to 23, configured to transmit and / or receive said plurality of packets as a wireless signal and to transmit said synchronization information in a wireless signal.

25. 25. A communications device according to any one of claims 1 to 24, configured to transmit and / or receive said plurality of packets as an optical signal, and to transmit said synchronization information in an optical signal.

26. 1. A communication method comprising: transmitting and / or receiving a plurality of packets using scheduling relative to a reference time; The method further comprises the step of transmitting synchronization information; the step of transmitting synchronization information includes the step of including timing information in the synchronization information defining a timing of transmission of the synchronization information relative to the reference time; Communication methods.

27. A non-transitory storage unit that stores instructions that, when executed by a processor, cause the processor to: Controlling transmission and / or reception of a plurality of packets using scheduling relative to a reference time; and controlling the transmission of synchronization information; the synchronization information includes timing information included within the synchronization information defining a timing of the transmission of the synchronization information relative to the reference time; Non-transient storage unit.

28. A communication device (16', 16"), said communication devices (16', 16") being adapted to receive synchronization information (81a, 81b); the communication device (16', 16") is configured to transmit and / or receive a plurality of packets using a scheduling relative to a reference time; said communication devices (16', 16") being adapted to evaluate timing information, contained in synchronization information (81a, 81b), defining a timing of transmission of said synchronization information (81a, 81b) relative to said reference time, in order to perform the synchronization; Communications equipment (16', 16").

29. 29. The communications device of claim 28, configured to evaluate from the timing information information relating to a time distance from a timing reference to a next timing reference.

30. 30. A communications device according to claim 28 or 29, configured to resynchronise by comparing the time position of the measured reference time with the timing information.

31. 31. A communications device as claimed in claim 29 or 30, configured to read the timing information to ascertain a time drift relative to said timing information, thereby correcting time knowledge with said time drift.

32. 32. A communications device as claimed in claim 29, 30 or 31, configured to count the number of slots between a current reference time and a start of the synchronization information, and to compare the counted number of slots with a number encoded in the timing information, thereby calculating an offset, and to compensate for the offset by adjusting its timing to the timing information.

33. 33. A communication device according to any one of claims 28 to 32, configured to receive scheduling information that assigns an exclusive time slot to the communication device and assigns different exclusive time slots to the different communication devices, such that the communication device transmits in the time slots assigned to it and refrains from transmitting in time slots assigned to different communication devices.

34. 34. A communications device according to any one of claims 28 to 33, configured to receive scheduling information allocating exclusive time slots to a master communications device for the transmission of the control signals, such that the communications device receives the control signals at least in time slots allocated for the transmission of the control signals.

35. 35. A communication device according to claim 28, configured to receive at least some control signals in an event-driven manner during unassigned time slots, such that the master communication device can occupy the unassigned slots for transmitting at least some control signals in an event-driven manner without necessarily scheduling those event-driven control signals.

36. 36. The communications device of claim 34 or 35, wherein the control signal includes scheduling information for a subsequent transmission.

37. 37. A communications device according to any one of claims 34 to 36, wherein the control signal includes the synchronization information for a subsequent transmission.

38. 38. The communication device of claim 34, wherein the control signal includes announcement information.

39. 39. The communications device of any one of claims 34 to 38, wherein the control signal includes random access timing information providing information regarding slots that are grant free.

40. 40. A communications device according to any one of claims 34 to 39, wherein the control signal includes granted access timing information providing information regarding time slots which are grant free.

41. 41. A communication device according to any one of claims 34 to 40, comprising or configured to be connected to an upper layer application (902), the communication device being configured to receive payload data from the upper layer application (902) and to transmit the payload data in accordance with the scheduling, and / or the communication device being configured to transmit payload data received in accordance with the scheduling to the upper layer application (902).

42. 42. A communication device according to any one of claims 28 to 41, wherein time slots not scheduled for the communication device are given to a different communication device if information about the characteristics of a real-time application data stream defined by a higher layer application requires a particular maximum latency for transmission and / or reception of a particular transmission.

43. 43. A communications device according to any one of claims 28 to 42, configured to estimate from the timing information a time distance between the encoded timing information and a measured timing reference.

44. 44. A communications device according to any one of claims 28 to 43, configured to adjust an internal clock to the encoded timing information in case of drift between the encoded timing information and a measured timing reference.

45. 45. A communications device according to any one of claims 28 to 44, configured to transmit and / or receive said plurality of packets as a wireless signal, and to receive said synchronization information in a wireless signal.

46. 45. A communications device according to any one of claims 28 to 44, configured to transmit and / or receive said plurality of packets as an optical signal, and to receive said synchronization information in an optical signal.

47. 1. A communication method comprising: receiving synchronization information; transmitting and / or receiving a plurality of packets using scheduling relative to a reference time; evaluating timing information contained in synchronization information and defining a timing of transmission of said synchronization information relative to said reference time, in order to perform the synchronization; A communication method comprising:

48. A non-transitory storage unit that stores instructions that, when executed by a processor, cause the processor to: Controlling receipt of synchronization information; Controlling transmission and / or reception of a plurality of packets using scheduling relative to a reference time; evaluating timing information included in the synchronization information and defining a timing of the transmission of said synchronization information relative to said reference time in order to perform the synchronization; A non-transient storage unit that performs the following:

Images