Multi-millisecond packet mode transmissions in an 802.15.4z system

Abstract

In order for 802.15.4z and 802.15.4ab communications to coexist in the same RTFS system, the 802.15.4z time structure comprises sequential measurement slots (RS) of one millisecond for a measurement cycle (RR) in which the 200 ps at the start of each slot are reserved for 802.15.4z communications and the remaining 800 μs are reserved for 802.15.4ab communications. The 800 μs are sub-divided into eight measurement sub-slots (RSS) of 100 μs. The sub-slots which are co-located in the sequential slots are grouped into a set (SET) of sub-slots, assigned to a UWB device for transmitting its 802.15.4ab fragments every millisecond. Multiple sets of sub-slots are formed in each control, initiation and response phase. Measurement packets are transmitted by the same device during the eight measurement cycles of a measurement block. Numerous UWB devices are located by 802.15.4ab each second, in addition to the locating by 802.15.4z

Description

[0001] MULTI-MILLISECOND PACKET TRANSMISSIONS IN AN 802.15.4Z SYSTEM

[0002] TECHNICAL FIELD

[0003] This disclosure relates generally to communications in wireless networks and, more specifically, to enhanced real-time location systems (RTLS) with ultra-wideband (UWB) networks.

[0004] CONTEXT OF THE INVENTION

[0005] ULB is a wireless technology recently added to mobile devices, which enables not only data sharing applications, but also many other use cases such as indoor positioning and navigation.

[0006] ULB is defined in the IEEE standard (registered trademark) 802.15.4 (latest version 802.15.4-2024) which includes in particular amendment 802.15.4z relating to improved telemetry techniques.

[0007] ULB data transmission uses very short, low-energy radio frequency pulses over a wide bandwidth of 500 MHz or more. ULB communications operate at frequencies between 3.1 GHz and 10.6 GHz, for example in a first band between 3.1 GHz and 4.8 GHz or in a second band between 6 GHz and 8.5 GHz.

[0008] With the growing adoption of ULB radios, several types of applications have emerged, each with specific requirements, depending on whether they focus on security (e.g., access control), communication between devices (e.g., radio direction finding), or the tracking or location of equipment (e.g., asset management). These specific requirements have led to numerous standards based on ULB.

[0009] FiRa (registered trademark) and Omlox (registered trademark) are two examples of protocols based on the 802.15.4z standard, each with its own specification. The Car Connectivity Consortium (CCC - registered trademark) also prepares and publishes its own specifications.

[0010] FiRa targets consumer applications with peer-to-peer distance measurement (telemetry) where a connection between two devices, including at least one mobile device, is established to allow them to calculate the distance between them and, potentially, their direction. Omlox targets industrial applications where the telemetry of mobile devices (or tags) is based on a set of time-synchronized infrastructure equipment (or beacons, satellites, or anchors), typically mounted on the ceiling of an area where the mobile devices operate.

[0011] The 802.15.4z standard (latest version IEEE Std 802.15.4z-2020 of June 2020) organizes the measurement time structure into measurement periods or Ranging Rounds (RR), each of which consists of three consecutive phases of successive slots (called measurement slots or Ranging Slots - RS or timeslot): a measurement control phase during which controllers (for example Omlox satellites) sequentially propagate synchronization signals across the network to the controlled (for example Omlox tags), an initiation phase during which initiators (controllers and / or controlled) transmit measurement messages (or packets or frames) in the downlink and a response phase during which responders (to the initiators) transmit measurement messages (telemetry) in the uplink to the satellites.

[0012] Generally the measurements are spread over several RR measurement cycles - i.e. several hundred milliseconds.

[0013] RTLS systems conforming to 802.15.4z can achieve accuracies on the order of a few tens of centimeters indoors, but at the cost of a large number of parallel initiator controllers distributed in the area of ​​operation of the responders (tags).

[0014] An improvement to the ULB standard is proposed by the 802.15.4ab working group, which has published a draft version of the standard: P802.15.4ab / D01 (June 2024). Below, "P802.15.4ab / D01" and "802.15.4ab" are used interchangeably.

[0015] ULB 802.15.4ab aims, in particular, to increase the range of ULB communications by introducing a multi-millisecond ULB packet mode (MMS). This series of transmissions allows the receiver to benefit from a digital gain through the integration of a longer message. The ULB MMS technique accumulates the channel impulse response (CIR) estimate from a sequence of measurement fragments that are sent at regular intervals, typically every millisecond. The sensitivity of the ULB measurement is thus improved.

[0016] Indeed, since each segment is very short (60 ps, ​​compared to a few hundred ps for 802.15.4z messages), it is possible to have a higher transmission power while remaining below the average power threshold. Because the fragments are spaced precisely one millisecond apart, corresponding to the measurement period defined in the regulatory standards, each fragment can be transmitted with increased power without exceeding the regulatory limit.

[0017] By increasing the range, the ULB MMS technical letter of sending successive fragments in a totally synchronous manner makes it possible to reduce the density of parallel initiator controllers (for example Omlox satellites) in areas where tracking or localization of responders (tags) is carried out.

[0018] However, there is a need to deploy this multi-millisecond packet mode in the presence of multiple initiating controllers and multiple responders.

[0019] There is also a need for backward compatibility and / or coexistence with the 802.15.4z standards already in use.

[0020] SUMMARY OF THE INVENTION

[0021] This disclosure proposes reusing the channel access time structure provided in 802.15.4z to organize ULB MMS transmissions, rather than redefining a new measurement time structure. The 802.15.4z time structure is thus adapted to accommodate multiple ULB MMS transmissions every millisecond, as required for 802.15.4ab communication. Advantageously, each RS measurement slot is designed to accommodate multiple transmitters.

[0022] The use of the 802.15.4z temporal structure also ensures support for 802.15.4z communications, such as Omlox or FiRa. This provides coexistence or backward compatibility.

[0023] For this purpose, the disclosure relates first of all to an ultra-wideband (ULB) device comprising a communication interface configured to: access co-located sub-slots respectively within successive measurement slots of a measurement cycle defined in a temporal measurement structure of an ULB infrastructure, and send successive fragments of a measurement packet into the accessed sub-slots.

[0024] Since measurement slots are defined temporally (timeslot), "colocalized sub-slots" should be understood as sub-slots whose temporal positions are identical in their respective slots.

[0025] Each measurement packet has an enhanced range resulting from the accumulation of fragments enhanced to regulatory power per millisecond.

[0026] The inventor observed an increase in link budget of up to 20 dBm compared to current practices respecting the regulatory constraints of ULB signal power.

[0027] The disclosure relates to a communication method comprising the following steps performed by an ultra-wideband (ULB) device: accessing co-located sub-slots within successive measurement slots of a measurement cycle defined in a measurement time structure of an ULB infrastructure, and sending successive fragments of a measurement packet into the accessed sub-slots. The disclosure also relates to an ultra-wideband (ULB) device comprising a communication interface configured to: receive successive fragments of a measurement packet in co-located sub-slots within successive measurement slots of a measurement cycle defined in a measurement time structure of an ULB infrastructure, and accumulate channel impulse responses of the successive fragments received.

[0028] Respectively, the disclosure relates to a communication process comprising the following steps carried out by an ultra-wideband (ULB) device: receiving successive fragments of a measurement packet in co-located sub-slots respectively within successive measurement slots of a measurement cycle defined in a measurement time structure of an ULB infrastructure, and accumulating channel impulse responses of the successive fragments received.

[0029] The disclosure also relates to an ultra-wideband (ULB) infrastructure comprising a plurality of synchronized ULB infrastructure equipment (typically satellites), the infrastructure equipment emitting synchronization signals to define a measurement time structure, the measurement time structure comprising one or more measurement cycles formed from a plurality of measurement slots, sub-slots co-located respectively within successive measurement slots being allocated (i.e., allocated or assigned) to the same ULB device for sending fragments of a measurement packet.

[0030] Respectively, the disclosure relates to a communication process comprising the following step carried out by an ultra-wideband (ULB) infrastructure formed of a plurality of synchronized ULB infrastructure equipment: emitting synchronization signals to define a measurement time structure, the measurement time structure comprising one or more measurement cycles formed of a plurality of measurement slots, sub-slots co-located respectively within successive measurement slots being allocated to the same ULB device for sending fragments of a measurement packet.

[0031] Optional embodiment characteristics are defined below.

[0032] In a transmission-side embodiment, the communication interface is configured to repeat the transmission of the measurement packet in several – typically eight or more – successive measurement cycles. This allows, in particular, a label to be effectively detected and located by the ULB infrastructure.

[0033] In one receiver-side embodiment, the communication interface is configured to accumulate channel impulse responses as successive fragments of a first measurement packet are received. When the accumulation exceeds a predefined threshold, it switches to receiving successive fragments of a second measurement packet transmitted in parallel with the first. The device also terminates the reception of the measurement packet prematurely because the fragments already received are sufficient for its detection. The device can then switch to receiving another parallel measurement packet, thereby improving measurement latency and increasing the number of parallel measurements.

[0034] In one embodiment, the measurement time structure allocates a start portion of each measurement slot in the measurement cycle to communications according to the IEEE 802.15.4z standard. The "start portion" refers to the first few moments of each relevant measurement slot. Each measurement slot can therefore be allocated, according to 802.15.4z (e.g., Omlox or FiRa), to a different ULB device to transmit an 802.15.4z measurement packet (typically an RFRAME frame).

[0035] According to 802.15.4z, the measurement packet duration (e.g., approximately one hundred microseconds) is short compared to the allocated time slot duration (e.g., 833 microseconds in Omlox). It turns out that the measurement packet can be confined to the beginning of the time slot without compromising the permitted distances between transmitting and receiving devices (since a 1-microsecond delay corresponds to a distance of 3000 m). Therefore, the remainder of the measurement time slot can be freed up for the implementation of ULB MMS communications according to 802.15.4ab.

[0036] In one embodiment, the initial portion lasts two hundred microseconds. This duration represents a good compromise between efficient use of 802.15.4z and freeing up as much time as possible for sub-slots dedicated to transmitting fragments of the measurement packet (i.e., for 802.15.4ab communications). Of course, other durations can be used, either longer (e.g., 250 ps) or shorter (e.g., 150 ps).

[0037] In one embodiment, the measurement slots last one millisecond.

[0038] In one embodiment, the sub-slots last one hundred microseconds. Of course, other values ​​can be used, higher (for example 200 ps) at the risk of reducing the number of ULB devices that can transmit simultaneously, or lower (for example 80 ps, ​​60 ps or even 32 ps) at the risk of degrading the reception latency (the elementary fragments being reduced, therefore a greater number are needed to detect the measurement packet).

[0039] In one embodiment, the temporal measurement structure defines a plurality of distinct games of sub-slots co-located within the same measurement slots, the games being assigned to distinct devices. The expression "distinct games" within the same measurement slots here means that the sub-slots of the multiple games are co-located at different (respective) times within the measurement slots. Therefore, the sub-slots of one game do not overlap the sub-slots of another game.

[0040] In one embodiment, a set of co-located sub-slots comprises sub-slots in four, eight, or sixteen successive measurement slots. Such an arrangement is suitable for a temporal structure conforming, for example, to Omlox, which provides for sixteen slots in the control phase and thirty-two slots in the initiation phase. In one embodiment, the measurement cycle comprises a control phase consisting of several measurement slots, followed by an initiation phase consisting of several measurement slots, followed by a response phase consisting of several measurement slots, with the co-located sub-slots assigned to the same ULB device being included in only one of these phases. This makes it possible to maintain an allocation of sub-slots to ULB devices that conforms to 802.15.4z, stipulating that in each phase only one type of ULB device can transmit (controllers, initiators, then responders).

[0041] In one embodiment, at least one of said phases comprises two or more sets of co-located sub-slots assigned to distinct ULB devices, the sub-slots of the two or more sets all being co-located within the measurement slots but in distinct sets of measurement slots.

[0042] In general, the measurement slots of a measurement cycle each comprise several sub-slots. Co-located sub-slots (i.e., corresponding to the same instant relative to the start of the corresponding slot) are, for example, organized into several sets of consecutive, non-overlapping sub-slots. Each set can be assigned to a given ULB device to transmit its measurement packet fragments.

[0043] In one embodiment, the control phase comprises sixteen measurement slots, the initiation phase comprises thirty-two measurement slots, and the response phase comprises seventy-seven measurement slots. Such a configuration makes it possible to preserve the macroscopic temporal structure of 802.15.4z with measurement cycles of 125 ms while offering sequences of co-located sub-slots spaced one millisecond apart, in accordance with 802.15.4ab.

[0044] The ULB infrastructure (e.g., Omlox satellites) is responsible for signaling the allocation of subslot sets to ULB devices. The use of co-located subslots simplifies signaling. In alternative implementations, subslots may not be co-located. The above also applies to the case of non-co-located subslots. Another aspect of disclosure concerns non-transient computing media storing a program which, when executed by a microprocessor or computer system in a ULB device, enables the ULB device to perform any of the processes described above.

[0045] BRIEF DESCRIPTION OF THE FIGURES

[0046] Other advantages and features of the invention will become apparent upon examination of the detailed description of the embodiment and implementation, which is by no means limiting, and the accompanying drawings, in which:

[0047] [Fig- i ] ;

[0048] [Fig. 2];

[0049] [Fig. 3];

[0050] [Fig. 4];

[0051] [Fig. 5];

[0052] [Fig. 6];

[0053] [Fig. 7];

[0054] [Fig. 8];

[0055] [Fig. 9]; and

[0056] [Fig. 10] schematically illustrate methods of implementation and realization of the invention.

[0057] DETAILED DESCRIPTION

[0058] To enable the coexistence of 802.15.4z and 802.15.4ab communications within the same RTLS system, the 802.15.4z time structure comprises successive one-millisecond measurement slots (RS) within a measurement cycle (RR). The initial 200 ps of each slot are reserved for 802.15.4z communications, and the remaining 800 ps are reserved for 802.15.4ab communications. These 800 ps are further subdivided into eight 100-ps measurement subslots (RS S). The subslots co-located within these successive slots are grouped into a subslot set (SET), which is assigned to a UWB device to transmit its 802.15.4ab fragments every millisecond. Several sets of sub-slots are formed in each control, initiation, and response phase. Measurement packets are transmitted by the same device during the eight measurement cycles of a measurement block. Numerous ULB devices are located via 802.15.4ab every second, in addition to locations via 802.15.4z.

[0059] Ultra-wideband technology (“ULB” and “UWB” are used hereafter as synonyms) has found numerous applications in various fields related to distance measurement and / or the localization of moving objects.

[0060] The IEEE 802.15.4 and 802.15.4z standards provide various details on exemplary UWB communication protocols. Variations of UWB communication protocols for various telemetry services include the UWB FiRa or FiRa protocol (meaning "fine telemetry") and the UWB Omlox or Omlox protocol, as well as the Car Connectivity Consortium (CCC) protocols. Details of the FiRa protocol at the MAC layer are provided by the following specification: "FIRA MEDIUM ACCESS CONTROL (MAC) TECHNICAL SPECIFICATION", VERSION 2.0.0.

[0061] Other communication protocols that may use the UWB frequency include the IEEE 802.1 l ax standard (and subsequent ones).

[0062] Figure 1 illustrates a SYS real-time location system (RTLS).

[0063] The SYS system is a fixed-range wireless network, here an Omlox system based on a fixed infrastructure of synchronized S1-S3 satellites (also known as anchors or beacons) and one or more T tags. Three satellites are shown for illustrative purposes; typically, more satellites are used in a tag range. Furthermore, although only one tag is shown here, it is common for multiple tags to operate simultaneously in the same range.

[0064] The S satellites serve as fixed reference points for determining the position of the T tags and constitute the ULB location infrastructure in a multi-satellite network. The T tags are UWB devices whose changing position must be located.

[0065] UWB devices, such as Omlox, have two interfaces: a UWB radio interface (also known as an in-band or IB radio) and a UWB out-of-band or OoB radio interface, which operates on a different channel than the one supporting UWB communications. The two interfaces are synchronized. The OoB interface conforms to the IEEE 802.15.4-2020 standard for low-power wireless networks, typically in the 2.4 GHz band. The IB interface is based on the IEEE 802.15.4z standard and also features UWB MMS functionality as introduced by the P802.15.4ab / D01 standard.

[0066] The OoB interface generally supports the activity (frame exchanges) of the discovery and management procedures of the UWB infrastructure. The IB interface generally supports the actual measurement activity (frame exchanges), that is to say, sensitive transmissions.

[0067] The S1-S3 satellites are UWB-compatible devices used as a fixed reference for positioning calculations or for managing a Real-Time Location System (RTLS) infrastructure. The synchronized satellite infrastructure constitutes a UWB network. A satellite propagates the network synchronization and organization (TDMA) over the IB via a telemetry control (RCM) message – this satellite is called a controller (in the 802.15.4z sense) – and participates in the initiation phase and collects propagation time measurements from all other satellites in order to perform telemetry calculations – this satellite is called an initiator (in the 802.15.4z sense).

[0068] A T-tag is a UWB-compatible device whose location within the network changes during use; it is therefore a mobile device. It can be a standalone device (e.g., a badge or key fob) typically attached to an object of interest, or it can be integrated into another device or be based on existing UWB devices (e.g., a smartphone). The tag generally behaves as a controlled and responsive device (in the 802.15.4z sense).

[0069] The infrastructure and the label (or labels) form the UWB system.

[0070] A UWB device performs a discovery procedure on the OoB to detect the presence of one or more UWB networks through a passive scanning mechanism, which is known and therefore not detailed here. The discovery makes it possible to obtain, from the UWB infrastructure, a configuration of measurement blocks ("Ranging Blocks" or RB) specifying the organization of measurement slots ("Ranging Slots" or RS) in measurement cycles ("Ranging Rounds" or RR).

[0071] Once the UWB network is chosen, the UWB device joins the network and authenticates itself with any controller / satellite, after which it can participate in the UWB network, and therefore in the measurement procedures on the IB.

[0072] Communications in the SYS system are structured in time by a ranging time structure defined by 802.15.4z.

[0073] Figure 2 illustrates a temporal measurement structure according to different embodiments. A 1-second measurement block RB is composed of eight measurement cycles RR according to a defined configuration of GTSW and LTW cycles (the standard predefines several possible configurations). Each 125 ms RR is composed of successive measurement time slots RS.

[0074] These RS measurement pulses are preferably of equal duration, typically one millisecond. Therefore, each RR measurement cycle (125 ms) is composed of 125 RS measurement pulses. Compared to Omlox, the number of RS pulses is reduced from 150 to 125. This duration advantageously allows for alignment with the FiRa (period = 1 ms) and CCC (2 ms) time structures.

[0075] In a time-scheduled ranging approach, RS slots are allocated to UWB devices. "Assigned" is synonymous with "assigned," "allocated," and "dedicated," meaning that the RS slot is reserved for a specific UWB device to transmit during that slot.

[0076] In a containment approach, RS slots are not reserved for particular UWB devices; UWB devices operate by containment to access an RS slot open to containment.

[0077] Each RR measurement cycle includes, for example, a PC control phase consisting of several measurement slots, for example 16, followed by a PI initiation phase consisting of several measurement slots, for example 32, followed by a PR response phase consisting of several measurement slots, for example 77. Of course, another distribution can be proposed.

[0078] In one embodiment, the RS slots of the PC control phase are reserved for controllers (e.g., satellites) that sequentially propagate synchronization signals across the network. These signals may include slot allocations or indications of their openness to contention. By varying the allocations / openings to contention, they are transmitted via the OoB.

[0079] The RS slots of the PI initiation phase are reserved for initiators (e.g., satellites) that transmit measurement messages in a downward link to the tags, initiating bidirectional measurement in certain embodiments. The RS slots can be assigned / allocated to specific satellites or be open to contention.

[0080] The RS slots in the PR response phase are reserved for responders (e.g., tags) to transmit uplink measurement messages. RS slots can be assigned / allocated to specific tags or be open to containment.

[0081] Indeed, various telemetry and localization techniques exist that may require messages from both an initiator and a responder (two-way telemetry or "TWR" - TWR), or only messages from a responder (uplink time-of-arrival difference or UL-TDoA), or only messages from an initiator (downlink time-of-arrival difference - DL-TDoA). All these techniques determine distances based on the time of flight of the emitted UWB pulses.

[0082] According to 802.15.4z, in an allocated RS slot, only a specific UWB device (i.e., a satellite or a tag) is allowed to transmit, thus preventing collisions. In an RS slot open to contention, the risk of collision is greater.

[0083] According to this disclosure, RS slots are used for the implementation of UWB MMS communications compliant with P802.15.4ab / D01, i.e. the transmission, every millisecond, of fragments composing a measurement packet, thus forming a sequence of transmitted fragments.

[0084] In the following, RS slots can be of either type (programmed or by contention).

[0085] P802.15.4ab / D01 introduces, in 802.15.4, a multi-millisecond UWB (MMS) packet mode that improves the sensitivity of UWB telemetry. The UWB MMS technique accumulates the channel impulse response (CIR) estimate from the sequence of fragments that are sent at successive milliseconds while using the regulatory transmit power budget allowed per millisecond.

[0086] Figure 3 illustrates a fragmented UWB MMS measurement packet. The UWB MMS packet consists of a series of measurement fragments, each sent at a distinct millisecond interval, allowing the receiver to use multiple fragments to improve sensitivity. The fragments are classified into three types: an initial fragment composed of known SYNC and SFD symbols, Ranging Sequence Fragments (RSFs), and Ranging Integrity Fragments (RIFs). Each RSF consists of a repetition of a symbol from a selected multi-millisecond measurement sequence (MMRS). Each RIF consists of a sequence of active STS pulses.

[0087] There are two general methods for initiating UWB MMS transmission and fragment accumulation. The first is narrow-band assisted (NBA) UWB MMS initiation. In this case, an O-QPSK PHY (different from UWB) is used for initialization, configuration, control, and communication of measurement results, and to initiate UWB switching for the exchange of UWB MMS packets / fragments. The second is UWB-driven UWB MMS initiation. In this case, the UWB PHY is used for control and communication of results, and to trigger the switch to UWB MMS packet mode at appropriate times.

[0088] In UWB MMS NBA, the O-QPSK PHY interface is used for the initialization, configuration, control, and reporting phases, while the UWB PHY interface is used for the measurement phase. In UWB-driven UWB MMS, the UWB PHY interface is used for the control, measurement, and reporting phases, while initialization and configuration can be performed by either the O-QPSK PHY interface or the OoB interface.

[0089] The control phase may include signaling the times ("measurement sub-slots" below) when to transmit the different fragments.

[0090] X being the number of RSF fragments and Y the number of RIF fragments. Different configurations are possible: a UWB MMS packet made up only of RSF, typically in location-oriented applications without security (integrity), in which case Y = 0 and X belongs to { 1 , 2, 4, 8, 16}; a UWB MMS packet made up only of RIF, in which case X = 0 and Y belongs to { 1 , 2, 4, 8}; a UWB MMS packet mixing RSF and RIF, in which case X belongs to { 1 , 2, 4, 8} and Y belongs to { 1 , 2, 4, 8}.

[0091] In the case of one-to-many UWB MMS measurements, an RR measurement cycle can be divided into several sub-cycles to perform MMS measurements with multiple UWB devices. This disclosure allows for combining MMS measurements with multiple UWB devices within a single RR measurement cycle, without the need for subdivision.

[0092] Figure 4 and Figure 5 illustrate two embodiments in which UWB devices access RS S (“Ranging Sub-Slots”) co-located respectively within successive RS measurement slots of an RR measurement cycle, and send successive UWB MMS fragments (Figure 3) of a measurement packet into the accessed sub-slots.

[0093] The signaling of the allocation of RSS sub-slots to UWB devices is preferably carried out during a control phase, either on the UWB IB, or on the NB channel (narrow-band of 802.15.4ab) if implemented, or on the OoB.

[0094] RSS subslot allocation signaling for 802.15.4ab can be combined (i.e., same signaling frame) with RS slot allocation signaling for 802.15.4z, for example via IB or via OoB.

[0095] Alternatively, these signals can be separated, in which case the allocation of RSS sub-slots can be carried out via the IB or NB channel. The signaling frames are not illustrated here.

[0096] Note that any NB channel (not shown) used for initialization, configuration, and control of the UWB IB can duplicate the superframe (hyperframe) structure of the OoB. Every NB channel is synchronized with the IB and the OoB.

[0097] Figure 4 illustrates eight (for illustrative purposes only) successive 1-millisecond RS measurement slots in an RR measurement cycle. These RS slots are, for example, allocated to UWB devices according to the 802.15.4z standard. They typically allow the transmission of eight consecutive RSF fragments.

[0098] In the diagram, each RS time slot begins at the top and ends one millisecond later at the bottom. The passage of time within an RS time slot is therefore illustrated by the vertical arrow on the left. The passage of time from one RS time slot to the next is illustrated by the horizontal arrow at the top. The transition from one RS time slot to the next is illustrated by the curved arrows from the beginning of one RS time slot to the beginning of the next.

[0099] A portion of the beginning of each RS time slot, here 200 ps (although other durations can be used), is reserved for standard 802.15.4z use, typically Omlox. An 802.15.4z UWB device is assigned to each RS time slot, enabling it to transmit an RFRAME frame in the beginning portion of the allocated time slot. The proposed time structure thus allocates the beginning portion of each RS measurement time slot to communications according to the IEEE 802.15.4z standard.

[0100] Preserving this initial portion advantageously allows for the coexistence of 802.15.4z communications with 802.15.4ab (UWB MMS) communications, as described below. Any other portion of the RS time slots besides the initial portion can be reserved as an alternative. Typically, an end portion or an intermediate portion can be used. Preferably, the same portion is retained throughout the RR measurement cycle, or even an RB measurement block (comprising eight RRs).

[0101] Alternatively, no portion of the RS slots is reserved for 802.15.4z communications.

[0102] According to the disclosure, the remaining RS slots are subdivided into RS S sub-slots of the same size, typically 100 ps, ​​with or without a margin between them (no margin in the examples described here). However, other lengths can be used. In the example, the 800 ps ending each RS slot are divided into eight 100 ps RS S sub-slots.

[0103] A 100 ps RSS sub-slot can be used as follows: 40 ps margin and 60 ps UWB MMS transmission.

[0104] RS S sub-slots having the same relative position within their RS slots (relative to the slot start) are said to be "co-located". For example, all RS S sub-slots extending from 200 to 300 ps within RS slots are "co-located". A co-location position can be identified using a co-location index.

[0105] We observe that the co-located RSS sub-slots are organized every millisecond. These co-located RSS sub-slots are therefore suitable for 802.15.4ab communications.

[0106] Also, the co-located RS S sub-slots are grouped into SET1 and SET2 games. In the example in the Figure, eight games are formed in parallel. These games are assigned to different UWB (802.15.4ab) devices, allowing them to transmit their UWB MMS fragments at millisecond intervals. For example, SET1 is assigned to satellite S1, SET2 to satellite S2, and so on. The proposed temporal structure thus defines a plurality of distinct games of co-located sub-slots within the same measurement slots, with the games being assigned to distinct devices.

[0107] In the illustrated example, each SET of co-located RS S sub-slots comprises sub-slots in eight successive measurement slots. Other values, for example 16, can of course be used, depending in particular on the chosen configuration (which fixes the X and Y values ​​above).

[0108] Eight UWB devices can communicate in parallel in the eight games SET 1 to SET8.

[0109] Figure 5 illustrates an example of integrating SET games into an RR measurement cycle according to 802.15.4z (typically Omlox). The three phases of PC control, PI initiation, and PR response are shown.

[0110] Each SET game is confined within a phase: the co-located sub-slots assigned to the same UWB device are therefore included in only one of said phases.

[0111] In this example, the control and initiation phase games comprise sixteen RS S colocalized sub-slots while the response phase games comprise eight RS S colocalized sub-slots.

[0112] Given the number of RS measurement slots in the initiation and response phases, these phases can include several successive plays at the same time location. In other words, these phases can include two or more plays of co-located sub-slots assigned to distinct UWB devices, with the sub-slots of the two or more plays all co-located within the measurement slots but in distinct sets of measurement slots. For example, SET21 and SET31 are successive, co-located within the same phase. Similarly, SET41, SET51, ... SET121 are also successive, co-located within the response phase. This therefore increases the number of UWB devices that can communicate according to 802.15.4ab.

[0113] In the proposed temporal structure, eight satellites (controllers) can transmit sixteen UWB MMS fragments during the 802.15.4z control phase (using SET11 to SET18, respectively). Sixteen satellites (initiators) can transmit sixteen UWB MMS fragments in 802.15.4ab during the initiation phase (using SET21 to SET38, respectively). Typically, measurements are repeated over the eight RR measurement cycles of an RB measurement block. Therefore, twenty-four satellites can perform unilateral DL-TDoA measurements every second.

[0114] Similarly, 72 (9*8) tags (responders) can emit eight UWB MMS fragments during the response phase (using SET41 to SET128 respectively). With repetition over the eight RR measurement cycles, 72 tags can be localized by unilateral UL-TDoA measurements every second.

[0115] Note that some tags can participate in bilateral measurements in cooperation with downlink transmissions from satellites during the initiation phase.

[0116] Figure 6 illustrates, using a flowchart, the steps of a 600 802.15.4z transmission process according to embodiments. The process can be implemented by a controller, an initiator, an responder, a satellite, or a tag.

[0117] Note that the transmission of UWB frames according to 802.15.4z in the beginning portions of RS measurement slots remains compliant with the 802.15.4z standard, and is therefore not described here.

[0118] At step S61, the device obtains its allocation of sub-slots. This can consist of receiving control / signaling frames transmitted by controllers or satellites (or alternatively, collaborating with other satellites).

[0119] The allocation specifies, for example, the allocated SET game. A SET game can be defined by the first slot RS of the game (between RS=0 and RS=124), the length L of the game (for example 4, 8 or 16 sub-slots RS S) and the colocation index or "offset" of the game (between 0 and 7 in the example) corresponding to the different colocation positions in the slots RS.

[0120] Once the SET is known, the UWB device accesses (step S62) the first sub-slot of the SET, then sends (step S63) the first fragment F (fragment number F# = 0) of the measurement packet. The process loops back to step S62 until the end of the sub-slots (F# = L) and thus the end of the transmission of fragments of the measurement packet.

[0121] Thus, the UWB device successively accesses the sub-slots of the allocated SET game, that is to say sub-slots co-located respectively within successive measurement slots of a measurement cycle defined in a temporal measurement structure of a UWB infrastructure, and sends successive fragments of a measurement packet into the accessed sub-slots.

[0122] Figure 7 illustrates 700 operations of the UWB device to process UWB 802.15.4z (left of Figure) and UWB 802.15.4ab (right of Figure) transmissions.

[0123] At step S71, the UWB device determines (using the allocation information for RS 802.15.4z slots and RS S 802.15.4ab sub-slots) the start of an RS slot of interest.

[0124] In which case, at step S72, it performs classic 802.15.4z operations in the beginning part of said RS slot (transmits a frame if the slot is allocated to it; receives a frame; or nothing), here during the 150 ps of the 200 ps of the beginning part (the final 50 ps are used here as a safety margin).

[0125] When these operations are completed, operations 802.15.4z consist of waiting (S73) for the end of the current RS slot, namely 850 ps.

[0126] In parallel, the 802.15.4ab operations are initiated by waiting (S74) for the sub-slot for 50 ps + k * 100 ps, ​​where k is the colocation index / offset of the sub-slot set (from 0 to 7 in the example). During the sub-slot, the UWB device sends (S75) the fragment F for 60 ps, ​​then increments (S76) the fragment counter: F#++. The test S77 verifies whether all fragments have been transmitted (all RS S sub-slots have been used). If not, the device waits (S78) for the end of the current slot (waiting for 40 ps + 800 ps - (k - l) * 100 ps) and returns to step S72. If yes, the fragment counter is reset (F#=0) and a new collocation index can be defined (if a different SET set is assigned to the UWB device for the next RR measurement cycle). This is step S79 followed by step S78 to wait for the end of the current RS slot.

[0127] Figure 8 illustrates, using a flowchart, the steps of an 800 802.15.4z reception process according to various embodiments. The process can be implemented by a controller, an initiator, a transponder, a satellite, or a tag. The process allows the device to locate another UWB device. A UWB device can simultaneously locate several other UWB devices by performing multiple instances of this process.

[0128] Note that the transmission of UWB frames according to 802.15.4z in the beginning portions of RS measurement slots remains compliant with the 802.15.4z standard, and is therefore not described here.

[0129] At step S81, the device obtains the allocation of sub-slots from another device to be located. Obtaining this allocation may consist of receiving control / signaling frames transmitted by satellites (or alternatively, collaborating with other satellites).

[0130] The allocation specifies, for example, the SET game allocated to the device to be located.

[0131] Once the SET is known, the UWB device waits for the first sub-slot of the SET and receives the first fragment F (fragment number F# = 0) of a measurement packet (step S82). The UWB device accumulates (S83) the CIR of this first fragment to an accumulation value (initially zero). The process loops back to step S82 until the end of the sub-slots (F# = L) and thus the end of the reception of fragments of a measurement packet.

[0132] Thus, the UWB device receives successive fragments of a measurement packet in sub-slots of the allocated SET game, i.e. sub-slots co-located respectively within successive measurement slots of a measurement cycle defined in a temporal measurement structure of a ULB infrastructure, and accumulates channel impulse responses of the successive fragments received.

[0133] The result of the accumulation can be exploited in accordance with P802.15.4ab / D01.

[0134] Figure 9 illustrates the 900 operations of the UWB device for processing UWB 802.15.4z (left of the figure) and UWB 802.15.4ab (right of the figure) receptions. The same steps as those in Figure 7 are referenced.

[0135] The operations differ as follows.

[0136] When the RS S sub-slot is reached following step S74, the device receives the fragment at step S95. It adds the received fragment to a receive buffer at step S96 in addition to incrementing the F# counter.

[0137] When all fragments have been received following the S77 test, the device performs full integration (accumulation in the sense of 802.15.4ab into the accumulation data) of the L received fragments (into the buffer), and stores the result. This is step S98. Step S99 follows, where the accumulation data is reset to 0, in addition to resetting the F# counter and adjusting the index.

[0138] A UWB device in receive mode can typically switch from one colocation index to another at the end of a measurement operation (usually spanning one measurement block, or 1 second). It can also listen successively, for each 125 ms cycle, to three downlink packets and nine uplink measurement packets.

[0139] Figure 10 illustrates a hardware architecture for a UWB device enabling the implementation of the above embodiments, typically one of the devices in Figure 1. It includes a 1001 communication bus to which the following are preferably connected:

[0140] - one or more central processing units 1002, such as one or more CPU processors and / or one or more microprocessors;

[0141] - a storage memory 1003, of type ROM and / or flash memory, for the storage of computer programs intended to implement all or part of the operations described above; - a random access memory 1004, of type RAM or even video RAM (VRAM), for the storage of the executable code of computer programs as well as the registers adapted to record variables and parameters necessary for their execution;

[0142] - one or more 1005 communication interfaces, typically UWB, connected for example to the IB, the OoB and / or the NB channel; and

[0143] - One or more I / O 1006 devices allowing an operator to interact with computer programs, both during configuration and operation. Typically, the I / O devices may include a screen serving as a graphical interface for the operator, which may be touch-sensitive or combined with a keyboard or other pointing device to allow the operator to interact with the programs.

[0144] The 1001 communication bus ensures communication and interoperability between the different elements included in or connected to the 1000 computer device.

[0145] The central processing unit 1002 is preferably adapted to control and direct the execution of instructions or parts of software code of the computer program(s). Upon power-up, the program(s) stored in non-volatile memory 1003 are transferred / loaded into the main memory 1004, which then contains the executable code of the program(s), as well as registers for storing the variables and parameters necessary for implementing the described processes.

[0146] Of course, this disclosure is not limited to the embodiments described above as examples; it extends to other variations. Other embodiments are possible.

[0147] For example, the descriptions above refer to UWB devices participating in one measurement procedure at a time. In some embodiments, the UWB devices (e.g., satellites and / or Omlox tags) are equipped with multiple transceivers that can operate in parallel. This results in improved latency. Furthermore, the descriptions above consider a UWB receiver device (Figure 8 and Figure 9) that listens to all L consecutive RS S measurement sub-slots to receive the L fragments of the transmitted measurement packet. However, in some embodiments, if the transmitted signal is strong, the UWB receiver device can bypass receiving all the fragments, for example, to switch to another measurement packet transmitted in parallel (in a parallel SET game).

[0148] Typically, the UWB receiving device measures the received signal level by performing a coherent integration of the received fragments after the reception of each fragment at step S98-2 (Figure 9) at output 'N' of the S77 test. As soon as the signal level is satisfactory (a test is set up, comparing the integration with a threshold value 'THR'), the UWB receiving device does not continue ('EXIT') the reception of other fragments, and can switch to another SET, in order to receive another measurement packet transmitted in parallel.

[0149] This adaptability feature ("scalability") improves latency and facilitates parallel measurements.

Claims

25 DEMANDS 1. Ultra-wideband (ULB) device comprising a communication interface configured to: access sub-slots (RS S) co-located respectively within successive measurement slots (RS) of a measurement cycle (RR) defined in a measurement time structure of an ULB infrastructure, and send successive fragments (F) of a measurement packet into the accessed sub-slots.

2. Device according to claim 1, wherein the communication interface is configured to repeat the sending of the measurement packet in several successive measurement cycles.

3. Ultra-wideband (ULB) device comprising a communication interface configured to: receive successive fragments (F) of a measurement packet in sub-slots (RS S) co-located respectively within successive measurement slots (RS) of a measurement cycle (RR) defined in a measurement time structure of an ULB infrastructure, and accumulate channel impulse responses of the successive fragments received.

4. Device according to claim 3, wherein the communication interface is configured to accumulate channel impulse responses as successive fragments of a first measurement packet are received and to switch, when the accumulation exceeds a predefined threshold value, to the reception of successive fragments of a second measurement packet transmitted in parallel with the first measurement packet.

5. Device according to any one of claims 1 to 4, wherein the measurement time structure allocates a start part of each measurement slot of the measurement cycle to communications according to the IEEE 802.15.4z standard.

6. Device according to claim 5, wherein the start part lasts two hundred microseconds.

7. Device according to any one of claims 1 to 6, wherein the measurement slots last one millisecond.

8. Device according to any one of claims 1 to 7, wherein the sub-slots last one hundred microseconds.

9. Device according to any one of claims 1 to 8, wherein the time-measurement structure defines a plurality of distinct games (SET) of co-located sub-slots within the same measurement slots, the games being assigned to distinct devices.

10. Device according to claim 9, wherein a set of colocated sub-slots comprises sub-slots in four, eight or sixteen successive measurement slots.

11. Device according to claim 9, wherein the measurement cycle comprises a control phase (PC) consisting of several measurement slots, followed by an initiation phase (PI) consisting of several measurement slots, followed by a response phase (PR) consisting of several measurement slots, the co-located sub-slots assigned to the same ULB device being included in only one of said phases.

12. Device according to claim 1 1 , wherein at least one of said phases comprises two or more sets (SET) of colocalized sub-slots assigned to distinct ULB devices, the sub-slots of the two or more sets all being colocalized within the measurement slots but in distinct sets of measurement slots.

13. Device according to claim 11 or 12, wherein the control phase (PC) comprises sixteen measurement slots, the initiation phase (PI) comprises thirty-two measurement slots and the response phase (PR) comprises seventy-seven measurement slots.

14. Ultra-wideband (ULB) infrastructure comprising a plurality of synchronized ULB infrastructure devices (SI, S2, S3), the infrastructure devices emitting synchronization signals to define a measurement time structure, the measurement time structure comprising one or more measurement cycles (RR) formed from a plurality of measurement slots (RS), sub-slots (RS S) co-located respectively within slots of successive measurements being assigned to the same ULB device for sending fragments of a measurement packet.

15. Communication method comprising the following steps carried out by an ultra-wideband (ULB) device: accessing (S62) co-located sub-slots respectively within successive measurement slots of a measurement cycle defined in a measurement time structure of an ULB infrastructure, and sending (S63) successive fragments of a measurement packet into the accessed sub-slots.

16. Communication method comprising the following steps carried out by an ultra-wideband (ULB) device: receiving (S82) successive fragments of a measurement packet in co-located sub-slots respectively within successive measurement slots of a measurement cycle defined in a measurement time structure of an ULB infrastructure, and accumulating (S83) channel impulse responses of the successive fragments received.

17. A communication method comprising the following step carried out by an ultra-wideband (ULB) infrastructure formed of a plurality of synchronized ULB infrastructure equipment: emitting synchronization signals to define a measurement time structure, the measurement time structure comprising one or more measurement cycles formed of a plurality of measurement slots, sub-slots co-located respectively within successive measurement slots being allocated to the same ULB device for sending fragments of a measurement packet.

18. Non-transient computer medium storing a program which, when executed by a microprocessor or computer system in an ultra-wideband (ULB) device, enables the ULB device to perform the process according to claim 15, 16 or 17.

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