Patent Description:
Future wireless communication networks are envisioned to play a key role in the development of smart manufacturing and industrial automation. Wireless communication shall be used to control production and increase efficiency, enable the digitalization of factories, integrate Internet of Things (IoT) and Machine-to-Machine (M2M) communication into the industrial ecosystem, and modernize logistics and transportation.

The communication requirements for supporting such use cases are challenging, mainly going into the direction of ultra-reliable and low-latency communication (URLLC), e.g. for coordinated actions of manufacturing robots. In such scenarios, periodicity is a typical situation, in order to implement efficient cycles including phases of measurements, processing and wireless data communication. To this end, predefined transmission/reception patterns between controllers (PLC) and sensors/actuators are naturally calling for semi-persistent scheduling (SPS). As a general rule, in most of such applications it is typical that packet errors in consecutive cycles are not permitted.

In particular, indoor communication in the mm-Wave frequency bands is considered as a major technical component. Key characteristics are the implementation of beamforming techniques, large available bandwidth, low/moderate mobility and channel dynamics, multi-path wave propagation and Non-Line-of-Sight (NLOS), and slow changes in the network topology.

<FIG> shows typical scenarios of industrial automation and their corresponding key parameters, as well as the requirements for the wireless network.

<FIG> shows an example of a production unit, which consists of an infrastructure point and several users, which are mounted on robotic arms controlled by the PLC.

<FIG> shows an example of industrial communication, which involves control loops with sensors/actuators and a controller, wherein latency puts constraints and limits on:.

At the same time, a reliability goal is to exclude with a very high probability non-permitted error behaviors, as e.g. data packet failures in consecutive cycles (see example in <FIG>). This does not (necessarily) translate into an SINR / spectral efficiency maximization. The main goal is to guarantee a certain (e.g. minimum) SINR, based on which modulation and coding can be adjusted. Limited information exchange leads to more challenges. This is addressed by exploiting sources of diversity and/or multi-point transmission.

However, reliability requirements fail in case of a "QoS failure", which occurs when at least one of following takes place:.

The present application focuses on the above-described special and more challenging requirements of industrial automation, particularly compared to conventional wireless (cellular) communication. Compared with other <NUM> use cases that are met in the vertical industry, e.g. vehicular communication, the present use case of industrial automation comes with very unique requirements, particularly in latency and reliability. One example is the fact that consecutive errors are not permitted, so that production cycles are not interrupted.

In conventional wireless communication systems, there exist and are used some concepts of changing beams and some general concepts of frequency hopping. However, the conventional communication systems do not provide a solution for industrial communication scenarios. With the conventional wireless communication systems, it is difficult to meet the reliability requirements, particularly in terms of packet failures and especially avoiding consecutive failures. In order to meet these requirements with the conventional wireless communication systems, the cost in terms of resources or complexity overhead to ensure robust transmission would be very high.

<CIT> discloses a method and apparatus for channel hopping between mobile stations and a base station in a radio communications system.

<CIT> discloses generating, by a network coordinator, a frequency hopping sequence to be used for communication between a network coordinator and a client, wherein the generated hopping sequence includes only select frequencies that minimize a probability of a predetermined number of consecutive frequency hop failures.

In view of the above-mentioned challenges of industrial automation, embodiments of the present application aim to improve the conventional wireless communication systems. An objective is to provide a wireless communications system, i.e. both a network device and a wireless communication device, better suitable for industrial communication scenarios. In particular, the aim is to meet reliability requirements in terms of packet failures. Consecutive failures should be avoided. Further, costs in terms of resources or complexity overhead should be held low.

Specific goals tackled by embodiments of the application are to:.

The objective and the goals are achieved by the embodiments provided in the enclosed independent claims. Advantageous implementations of the embodiments are further defined in the dependent claims. In the following, parts of the description and drawings referring to embodiments not covered by the claims, are not part of the invention, but are illustrative examples necessary for understanding the invention.

In particular the present application proposes beamforming and time/frequency resource allocation, in order to achieve a reliable communication for SPS multi-point transmissions.

A first aspect of the application provides a network device (BS), in particular for cyclic communication, configured to: provide a first information defining a hopping sequence to a wireless communication device (UE), wherein the hopping sequence specifies at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, es to be used by the UE for transmissions to and/or from the BS; and provide a second information to the UE defining when the hopping sequence should be periodically repeated and including a maximum number of communication failures for which the hopping sequence is valid.

By providing the two elements of information, the UE is instructed to use a dedicated sequence and repetition of the resources. This leads to higher reliability in terms of packet failures, and in particular consecutive failures are avoided. Thus, the device of the first aspect is suited well for the industrial automation scenario.

The provision of the two elements of information can be in a single or multiple messages, for example it can be comprised in a message with control information. Cyclic communication can be realized by a semi-persistent communication scheme and/or an SPS or another industrial control system.

A spatial resource may include a B S-beam and/or a UE-beam, beam pair, and/or a transmission- and/or reception point (TRP) and/or a radio resource may include a time-domain, and/or frequency-domain, and/or code-domain radio resource.

In an implementation form of the first aspect, the network device is configured to: provide the first information defining a hopping pattern to multiple UEs, wherein the hopping pattern comprises different hopping sequences, one hopping sequence for each of the multiple UEs.

Thus, the multiple UEs are instructed to use the resources in a dedicated sequence among each other. The hopping pattern leads to higher reliability in terms of packet failures, and in particular consecutive failures are avoided.

In an implementation form of the first aspect, the network device is configured to: calculate at least one hopping sequence.

In an implementation form of the first aspect, the network device is configured to: obtain a measurement, in particular a signal strength and/or a signal-to-interference-plus-noise ratio (SINR) from at least one UE, TRP, and/or another BS, and calculate the at least one hopping sequence on the basis of the received at least one measurement.

By using the measurements to generate the hopping pattern, reliability can be further improved.

In an implementation form of the first aspect, the second information specifies a period of time and/or a number of successive transmissions, for which the at least two spatial resources and/or the at least two radio resources are to be successively used by the UE.

In an implementation form of the first aspect, the network device is configured to: obtain feedback information about a communication failure from the UE, and provide a third information about an updated hopping sequence, updated based on the received feedback information, to the UE.

The updated hopping sequence may specify at least two spatial resources and/or radio resources to be successively used by the wireless communication device, as of receiving the updated hopping sequence, for successive transmissions to and/or from the network device. A communication failure can be a missed packet and/or based on a QoS failure (QoS failure as defined above).

By providing the updated hopping sequence, the communication failure can be addressed and accordingly reliability is improved.

In an implementation form of the first aspect, the second information further specifies a spatial resource and/or radio resource to be used by the UE to provide the feedback information to the BS, and the network device is configured to obtain the feedback information from the UE according to the spatial resource and/or radio resource specified by the second information.

Thus, also the feedback of one or more UEs to the network device is reliable.

In an implementation form of the first aspect, the second information further includes a spatial and/or radio resource for providing feedback information.

In an implementation form of the first aspect, the network device is configured to: provide a fourth information related to the first information and/or the second information defining a backup hopping sequence to be used by the UE, as of occurrence of a communication failure, for transmissions to and/or from the BS.

Thus, the communication failure can be addressed quickly and efficiently, which avoids interruption of e.g. an industrial automation process.

A second aspect of the application provides a wireless communication device (UE) configured to: receive a first information defining a hopping sequence from a BS, wherein the hopping sequence specifies at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, and receive a second information from the BS defining when the hopping sequence should be periodically repeated and including a maximum number of communication failures for which the hopping sequence is valid, and use the at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, for transmissions to or from the BS according to the second information.

By receiving the two elements of information, the UE can implement the sequence of using the resources such that its communication with the network device becomes more reliable, particularly in terms of packet failures. Thus, the device of the second aspect is well suited for industrial automation scenarios.

In an implementation form of the second aspect, the wireless communication device is configured to: use the at least two spatial resources and/or at least two radio resources specified by the hopping sequence for transmissions of a first transmission cycle, and again for transmissions of at least one second transmission cycle.

Thus, cyclic communication with high reliability can be implemented, which is well suited for industrial automation scenarios.

In an implementation form of the second aspect, a spatial resource includes a UE-beam and/or a BS-beam, and/or a TRP, and/or a radio resource includes a time-domain, and/or frequency-domain, and/or code-domain radio resource. By providing diversity, the communication between network device and wireless communication device is made highly reliable.

In an implementation form of the second aspect, the wireless communication device is configured to: obtain, particularly upon a request from the BS, a measurement, particularly a SINR in one or more radio resources while using a certain spatial resource, and transmit the measurement to the BS.

In an implementation form of the second aspect, the wireless communication device is configured to: transmit feedback information about a communication failure to the BS, receive a third information about an updated hopping sequence from the BS.

The updated hooping sequence may specify at least two spatial resources and/or radio resource, and the wireless communication device may use, as of receiving the updated hopping sequence, the at least two spatial resources and/or radio resources specified by the updated hopping sequence for transmissions to and/or from the BS.

In an implementation form of the second aspect, the second information specifies a further spatial resource and/or radio resource to be used by the UE to provide the feedback information to the BS, and the UE is configured to: transmit the feedback information to the BS in said further spatial resource and/or radio resource specified by the second information.

A third aspect of the application provides a method for a network device (BS), the method comprising: providing a first information about a hopping sequence to a wireless communication device (UE), wherein the hopping sequence specifies at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, to be used by the UE for transmissions to and/or from the BS, and providing a second information to the UE defining when the hopping sequence should be periodically repeated and including a maximum number of communication failures for which the hopping sequence is valid.

In an implementation form of the third aspect, the method comprises: providing the first information defining a hopping pattern to multiple UEs, wherein the hopping pattern comprises different hopping sequences, one hopping sequence for each of the multiple UEs.

In an implementation form of the third aspect, the method comprises: calculating at least one hopping sequence.

In an implementation form of the third aspect, the method comprises: obtaining a measurement, in particular a signal strength and/or a SINR from at least one UE, TRP, and/or another BS, and calculating the at least one hopping sequence on the basis of the received at least one measurement.

In an implementation form of the third aspect, the second information specifies a period of time and/or a number of successive transmissions, for which the at least two spatial resources and/or the at least two radio resources are to be successively used by the UE.

In an implementation form of the third aspect, the method comprises: obtaining feedback information about a communication failure from the UE, and providing a third information about an updated hopping sequence, updated based on the received feedback information, to the UE.

In an implementation form of the third aspect, the second information further specifies a spatial resource and/or radio resource to be used by the UE to provide the feedback information to the BS, and the method comprises: obtaining the feedback information from the UE according to the spatial resource and/or radio resource specified by the second information.

In an implementation form of the third aspect, the second information further a spatial and/or radio resource for providing feedback information.

In an implementation form of the third aspect, the method comprises: providing a fourth information related to the first information and/or the second information defining a backup hopping sequence to be used by the UE, as of occurrence of a communication failure, for transmissions to and/or from the BS.

The method of the third aspect and its implementation forms achieve the same advantages and effects as the device of the first aspect and its respective implementation forms.

A fourth aspect of the application provides a method for a wireless communication device (UE), the method comprising: receiving a first information about a hopping sequence from a network device (BS), wherein the hopping sequence specifies at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, receiving a second information from the BS defining when the hopping sequence should be periodically repeated and including a maximum number of communication failures for which the hopping sequence is valid, and using the at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, for transmissions to or from the BS according to the second information.

In an implementation form of the fourth aspect, the method comprises: using the at least two spatial resources and/or at least two radio resources specified by the hopping sequence for transmissions of a first transmission cycle, and again for transmissions of at least one second transmission cycle.

In an implementation form of the fourth aspect, a spatial resource includes a UE-beam and/or a BS-beam, and/or a TRP, and/or a radio resource includes a time-domain, and/or frequency-domain, and/or code-domain radio resource.

In an implementation form of the fourth aspect, the method comprises: obtaining, particularly upon a request from the BS, a measurement, particularly a SINR in one or more radio resources while using a certain spatial resource, and transmit the measurement to the BS.

In an implementation form of the fourth aspect, the method comprises: transmitting feedback information about a communication failure to the BS, receive a third information about an updated hopping sequence from the BS.

In an implementation form of the fourth aspect, the second information specifies a further spatial resource and/or radio resource to be used to provide the feedback information to the BS, and the method comprises: transmitting the feedback information to the BS in said further spatial resource and/or radio resource specified by the second information.

The method of the fourth aspect and its implementation forms achieve the same advantages and effects as the device of the first aspect and its respective implementation forms.

To summarize, the above aspects and implementation forms achieve improved reliability through applying diversity, which in general is obtained in time, frequency, space (beam) and/or multiple transmit/receive points, i.e. multiple radio links. A certain (minimum) SINR can be guaranteed, in order to avoid packet errors, rather than maximizing the SINR or data throughput. Multi-point diversity is particularly helpful against link blockage in industrial environments using mm-Wave communication, and where a large number of connected infrastructure nodes are used.

In every time transmission, e.g. cycle/frame, each UE can for example be served by one or more transmit receive points (TRPs), and further from each TRP by a predefined beam (Tx-Rx beam pair) and/or on a predefined frequency band and time slot/symbol within the cycle/frame. In the same cycle/frame, other frequency bands, time slots/symbols and/or beams may be used, in order to serve other UEs from the same or another TRP.

The above described aspects and implementation forms of the present application will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which.

<FIG> shows a network device <NUM>, particularly a Base Station (BS), like a gNodeB or infrastructure node, and a wireless communication device <NUM>, particularly User Equipment (UE), according to embodiments of the application. In particular, the devices <NUM> and <NUM> are configured for performing cyclic communication, i.e. a communication that is cyclically repeated. The devices <NUM> and <NUM> are particularly well suited for industrial automation scenarios.

The BS is configured to provide a first information <NUM> defining a hopping sequence <NUM> to the UE <NUM>. The first information <NUM> may include the hopping sequence <NUM> or may allow the UE <NUM> to derive the hopping sequence <NUM>. Accordingly, the UE <NUM> is configured to obtain and/or receive the first information <NUM> defining the hopping sequence <NUM> from the BS <NUM>.

The BS <NUM> is further configured to provide a second information <NUM> to the UE <NUM> defining when the hopping sequence <NUM> should be repeated, in particular periodically repeated (i.e. my defined a "cycle"). Accordingly, the UE <NUM> is configured to obtain and/or receive the second information <NUM> from the BS <NUM>, and may determine from the second information <NUM> when to repeat the hopping sequence <NUM>.

The hopping sequence <NUM> specifies at least two spatial resources and/or at least two radio resources to be used by the UE <NUM> for transmissions <NUM> to and/or from the BS <NUM>. In particular, the UE <NUM> is thus configured to use the at least two spatial resources and/or at least two radio resources determined by the hopping sequence <NUM> for its transmissions <NUM> to and/or from the BS <NUM>, and according to the second information <NUM>, e.g. when, how often, and for how long.

The network device <NUM> may in particular be configured to provide the first information <NUM> to multiple UEs <NUM>. In this case, the first information <NUM> may define a hopping pattern, which comprises different hopping sequences <NUM>, specifically one hopping sequence <NUM> per each of the multiple UEs <NUM>. Each hopping sequence <NUM> in the hopping pattern specifies in this case at least two spatial resources and/or at least two radio resources for one of the UEs <NUM> to use for its transmissions <NUM>.

The at least two spatial resources may generally include one or more BS-beams and/or one or more UE-beams, one or more beam pairs, and/or one or more TRPs. The at least two radio resource may include one or more time-domain, and/or one or more frequency-domain, and/or one or more code-domain radio resources. This holds for both hopping sequence <NUM> and hopping pattern.

In particular, for consecutive transmissions <NUM> to/from the BS <NUM>, the hopping sequence <NUM> may specify one or preferably even more of the following hopping types (with reference to <FIG>):.

The benefits of these hopping types are:.

A joint spatial-frequency hopping type is particularly powerful against LOS blockage and frequency-selective fading, and "randomizes" the channel as observed between Tx and Rx in different transmissions <NUM>. This increased diversity, for instance, reduces the probability of QoS failures in consecutive time slots, thus leading to an improved performance. Combinations of different hopping types in a hopping sequence <NUM> may include a selection of TRPs, Tx/Rx beam pairs and time/frequency resources, in order to guarantee a certain QoS (e.g. min SINR).

Notably, considering e.g. spatial hopping, beam pairs may typically be selected by beam alignment. However, especially in NLOS conditions, exhaustive beam alignment and tracking may only offer small gains, while being complex and potentially introducing large delays. Further, frequent updating may be needed, in order to ensure using the best beam pair, which may increase complexity and may introduce a time delay. For example, in case of a beam failure, a beam alignment may have to be performed, possibly affecting the data connection.

Thus, each UE <NUM> according to an embodiment of the application (as e.g. shown in <FIG>) may preferably be scheduled and served in SPS way, in particular in different time intervals, by using different beam (pairs) and on different frequencies, which may be selected based on initial measurements. This provides the following benefits:.

<FIG> depicts an example of a hopping pattern for <NUM> UEs <NUM> ("users"; distinguished by different shadings), the hopping pattern accordingly including <NUM> hopping sequences <NUM>, one for each UE <NUM> according to an embodiment of the application. Further, the example includes <NUM> frequency bands (as frequency resources), six beam pairs (as spatial resources) and a <NUM>-cycle periodicity. B1 to B6 are (pairs of Tx-Rx) beams, which are selected from a set of initial beam measurements performed between Tx and Rx. Assignment may be such that different beams and frequencies are used in consecutive cycles. This prevents from failures in consecutive cycles for the same UE <NUM>. The hopping pattern with the hopping sequences <NUM> is instructed by the BS <NUM> to each UE <NUM>, and may then be used repeatedly unless it is updated by the BS <NUM>, e.g. in case of insufficient SINR, beam failure or high packet losses. In this case, the BS <NUM> may be configured to provide a third information about an updated hopping sequence <NUM>, updated based on the insufficient SINR, beam failure or high packet losses, to a UE <NUM> or an updated hopping pattern to the multiple UEs <NUM>.

<FIG> clarifies the benefits of the devices <NUM> and <NUM> according to embodiments of the application, which use a hopping sequence <NUM> or hopping pattern (see <FIG>) when compared to a conventional scheme without such hopping (see <FIG>). As can be observed, in the conventional scheme the reliability may suffer due to consecutive errors, and at the same time, in case of beam failure, a new beam search needs to be activated. This will take two cycles for the new beam search to take place, which increases the overall delay. The scheme implemented by the devices <NUM> and <NUM> does not suffer from these disadvantages.

<FIG> shows an example of steps of a procedure between the BS <NUM> ("infrastructure node") and a UE <NUM> ("user"). Here, the events of a QoS failure on both the BS side as well as on the UE side are included. The procedure between BS <NUM> and the UE(s) <NUM> may include:.

The feedback configuration information, which is included in the control information (i.e. the second information) may specifically include following information:.

<FIG> shows an example of <NUM> UEs <NUM>, which report feedback in a predefined time and frequency resource (RB), each one by using the assigned beam. Different UEs' feedback can be multiplexed in time, frequency and/or beam.

It is noted that multiple UEs <NUM> served by a single BS <NUM> do not necessarily need to have the same hopping sequence <NUM> periodicity. However, it is required that the period of the longest cycle is a multiple of the other users' shorter periods. Control information is initially sent before the beginning of the first cycle for all users.

However, feedback information can be reported - if needed - by each UE <NUM> independently after its own frame, i.e. after its own cycle(s). This allows for sending additional control information to these particular UEs <NUM>, e.g. immediately after their feedback information has been received by the BS <NUM>, in order to be used for adjusting transmission <NUM> in the next frames.

The scheme described above may also be extended to multi-point coordination and hopping sequence/pattern alignment. In this case, which is exemplarily shown in <FIG>, hopping sequences/patterns are jointly decided for more than one BS <NUM>. This requires information exchange between the BSs <NUM> or with a central control unit. Serving UEs <NUM> from more than one BS <NUM> offers an additional degree of freedom, which may be used to:.

The benefits of exchanging information between coordinated BSs <NUM>, or between each BS <NUM> and a central unit, include interference mitigation through joint pre-agreement of hopping sequences/patterns, enhancement of spatial diversity and throughput, e.g. through coordinated transmission even on same resources. Depending on the level of coordination and the required information exchange, hopping sequences/patterns can be aligned to:.

<FIG> shows a sequence diagram for an exemplary case of two BSs <NUM> ("Node <NUM>", "Node <NUM>") and two UEs <NUM> ("Receiver <NUM>", "Receiver <NUM>") being served. Depending on the architecture type (distributed/centralized), the BSs <NUM> may exchange information among each other or with a central unit. Then, based on the feedback information and hopping pattern changes, the signaling between BSs <NUM> and the central controller may need to be updated accordingly.

The procedure and information exchange may include following steps: each BS <NUM> may collect measurements from its attached UEs <NUM>, and a - potentially - a subset of measurements is shared between BSs <NUM> and the central unit, e.g. including a coarse preselection of resources and beams to be used. After hopping sequences/patterns are finalized, they are shared from the central unit to the BSs <NUM> (or among them) and each BS <NUM> instructs its UEs <NUM> accordingly.

In case a BS <NUM> receives a communication failure report from a UE <NUM>, the hopping sequence <NUM> of the UE <NUM> may be updated by its serving BS <NUM>. The changes with respect to the initial hopping sequence <NUM> may be shared with the other BSs <NUM>. In case the other BSs <NUM> - according e.g. to a predefined rule and the available information - update any of their own hopping sequences/patterns, update information is exchanged between all BSs <NUM>. This is schematically shown in <FIG>.

<FIG> shows a procedure of a UE <NUM> in case of a communication failure. In particular, in case of the communication failure, e.g. a QoS failure, in the downlink, the UE <NUM> may follow the shown procedure, which is aligned with the sequence diagram and the overall procedure. This UE-side procedure relies on own measurements, as well as on the information exchange with the infrastructure.

At first, the UE <NUM> may be configured to determine whether a beam for providing feedback information failed. If yes, then the UE <NUM> may use another beam to report the communication failure to the BS <NUM>. If the UE <NUM> then receives confirmation or a new hopping sequence <NUM> or hopping pattern, it may updated its hopping sequence <NUM> or the hopping pattern according to the instructions from the BS <NUM>. If not, then it may use another beam to inform the BS <NUM> about the failure, and may use the beam for data. If it still does not receive any instructions after a determined number of attempts, it may use a RACH procedure.

<FIG> shows a method <NUM> according to an embodiment of the application, which may be performed by the BS <NUM> (as e.g. shown in <FIG>). The method <NUM> includes a step <NUM> of providing a first information <NUM> about a hopping sequence <NUM> to a UE <NUM>, wherein the hopping sequence <NUM> specifies at least two spatial resources and/or at least two radio resources to be used by the UE <NUM> for transmissions <NUM> to and/or from the BS <NUM>. The method <NUM> further includes a step <NUM> of providing a second information <NUM> to the UE <NUM> defining when the hopping sequence <NUM> should be repeated, in particular, periodically repeated.

<FIG> shows a method <NUM> according to an embodiment of the application, which may be performed by the UE <NUM> (as e.g. shown in <FIG>). The method <NUM> includes a step <NUM> of receiving a first information <NUM> about a hopping sequence <NUM> from a BS <NUM>, wherein the hopping sequence <NUM> specifies at least two spatial resources and/or at least two radio resources. Further, the method <NUM> includes a step <NUM> of receiving a second information <NUM> from the BS <NUM> defining when the hopping sequence <NUM> should be repeated, in particular periodically repeated. Finally, the method <NUM> comprises a step <NUM> of using the at least two spatial resources and/or at least two radio resources for transmissions <NUM> to and/or from the BS <NUM> according to the second information <NUM>.

Claim 1:
Network device, BS, (<NUM>) for cyclic communication, configured to:
provide a first information (<NUM>) defining a hopping sequence (<NUM>) to a wireless communication device, UE, (<NUM>),
wherein the hopping sequence (<NUM>) specifies at least two spatial resources or at least two radio resources, or at least two spatial resources and at least two radio resources, to be used by the UE (<NUM>) for transmissions (<NUM>) to and/or from the BS (<NUM>); and
provide a second information (<NUM>) to the UE (<NUM>) defining when the hopping sequence (<NUM>) should be periodically repeated and including a maximum number of communication failures for which the hopping sequence (<NUM>) is valid.