WO2019214812A1

WO2019214812A1 - Multi-antenna mobile device and network devices for wireless communications

Info

Publication number: WO2019214812A1
Application number: PCT/EP2018/061923
Authority: WO
Inventors: Apostolos KOUSARIDAS; Panagiotis SPAPIS; Serkan AYAZ; Jose Francisco MONSERRAT; Sandra ROGER
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-05-08
Filing date: 2018-05-08
Publication date: 2019-11-14
Also published as: CN112154680B; EP3782391A1; CN112154680A

Abstract

The present invention provides a mobile device and a network device, respectively, for wireless communications, particularly V2X communications. The mobile device comprises more than one antenna. The mobile device is configured to transmit capability information to a network device and/or another mobile device. The capability information includes an indication regarding the capability of the mobile device to communicate using multiple antennas, and includes an antenna characteristic of, at least, one of the multiple antennas. The network device is configured to receive the capability information from the mobile device, and to determine an antenna set to be used by the mobile device for communicating with the other mobile device based on the received capability information. Then, the network device is configured to transmit information about the antenna set to the mobile device. Alternatively, mobile devices could exchange capability and characteristics information among each other so as to make a distributed selection about the best antenna set to be used.

Description

MULTI-ANTENNA MOBILE DEVICE AND NETWORK DEVICES FOR

WIRELESS COMMUNICATIONS TECHNICAL FIELD

The present invention relates to a mobile device and a network device for wireless communications, respectively. Thereby, the mobile device is configured to communicate particularly with multiple antennas with another mobile device, and the network device is configured to select the multiple antennas used for such communication between the mobile devices. The mobile device and network device of the invention are especially suited for Vehicle-to-Everything (V2X) communications, e.g. Vehicle-to- Vehicle (V2V), vehicle-to-infrastructure and/or vehicle-to-pedestrian communications. BACKGROUND

With the advent of automated driving functions, vehicles will be connected, and they will communicate for the exchange of sensor data and planned trajectories. Autonomous driving sets strict performance requirements (latency, reliability, capacity) for the 5G communication systems. For instance, less than 10 ms end-to-end latency and reliability higher than 99.99% are required, in order to support a wide range of V2X use cases (e.g., cooperative collision avoidance, high density platooning, cooperative perception of self driving vehicles, etc.; see 3GPP TS 22.186 V.15.00: Service Requirements for enhanced V2X scenarios (Release 15), March 2017).

The availability of multiple antennas in future vehicles enables the possibility to enhance V2X communications by exploiting Multiple-Input Multiple-Output (MIMO) or diversity techniques. Whereas in single- antenna vehicular communications the transmission is by default assumed to happen between antennas located on the roof of the transmitter and receiver vehicles, it was shown that there are other antenna positions, which can be more advantageous (experience lower pathloss) for V2V communications, depending on the specific communication context. For example, FIG. 18 provides an overview of a sidelink communication scenario, which exploits the diversity of multi-antenna links. As shown in the top half of FIG. 18, a transmitter vehicle and two receiver vehicles, which are equipped with multiple antennas, are involved in a wireless communication. In the bottom half of FIG. 18, after an antenna set for the communication is selected, every vehicle has a designated set of antennas readily operating to carry out the wireless communication.

However, existing LTE Radio Resource Control (RRC) and Radio Resource Management (RRM)/scheduling procedures for sidelink focus only on the single antenna case. They have not been designed for multi-antenna and multi-link V2X communication, where important new challenges arise, namely:

• Different types of vehicles may have different antenna positions and features.

• Individual configuration of each antenna element and coordination between the antennas is needed due to the diverse characteristics of these antennas.

• Multi-link connectivity is not enabled in a coordinated manner.

• Demanding performance requirements (low latency, high reliability, etc.) of V2X use cases should be taken into account.

According to the conventional solutions, it is possible to configure some aspects of sidelink V2X communication, for instance:

• A User Equipment (UE) can transfer radio access capability information to the E- UTRAN using the UE capability transfer procedure. However, these procedures do not consider the existence of multiple antennas and the specific characteristics that they have.

• Conventional sidelink procedures for resource allocation and scheduling are focusing on a single antenna without considering multi-link V2V or multiple antennas.

Another related solution is the use of MIMO in sidelink, as it is used in downlink or uplink. MIMO sidelink with antennas located in different parts of the vehicle has already been considered in literature, showing important benefits in terms of capacity increase and reliability. However, there is not any current 3GPP standard addressing MIMO in sidelink. Regarding the selection of the antenna to be used in MIMO communications, the majority of conventional solutions for massive MIMO require channel knowledge, which is a drawback for vehicular communications due to mobility. Other solutions for antenna selection/pairing for MIMO device-to-device (D2D) systems rely on multi-path channel state information (unsuitable for high mobility environments), and their complexity grows with the number of antennas and D2D pairs.

SUMMARY

In view of the above-mentioned challenges and disadvantages, the present invention aims to improve the conventional solutions. The present invention aims to extend conventional implementations for wireless communications, e.g. 5G Medium Access Control (MAC), RRC and Radio Resource Management (RRM) procedures, in order to exploit the diversity of the multi-antenna links. Thereby, especially wireless sidelink communications are considered. The present invention has in particular the aim to select the most appropriate set of antennas for wireless communications among two mobile devices, e.g. for V2V communications between two vehicles, particularly taking into account road and radio conditions. Furthermore, the invention desires to enable a coordinated establishment of multiple links, using different antennas among two or more mobile devices for specific (e.g. V2X) services, in order to increase reliability, capacity and improve latency of the communications. Both network-based (mode 3 in LTE standard nomenclature) and autonomous (mode 4 in LTE standard nomenclature) multi-antenna resource control and allocation should be considered.

Accordingly, the objective of the present invention is to provide a network device and mobile device, and a method, which enable and support antenna selection for improved wireless communications. In particular, the present invention aims at enabling the support of antenna selection for improved wireless V2X communications.

The objective of the present invention is achieved by the solution provided in the enclosed independent claims. Advantageous implementations of the present invention are further defined in the dependent claims. In particular, the present invention proposes enhancing wireless, particularly V2X communications, based on antenna selection for mobile device to mobile device (e.g. vehicles’ sidelink) communications. The antenna selection decision can thereby be made: a) in a centralized manner (network-based control/coordination) e.g., by a Base Station (BS), Access Management Function (AMF) in 5G network, cloud server operated by the MNO or not or any other network device, or b) in a distributed manner by autonomous mobile devices (e.g. vehicles; vehicle-based control/coordination). For the development of this idea, together with multi-link establishment, the following solutions are generally developed:

• Signaling used by the mobile device to inform the network device or other surrounding mobile devices about its capability to communicate using multiple antennas and the antenna characteristics.

• Signaling to provide information from the mobile devices to the network device or other surrounding mobile devices for radio and road conditions, relative positions to support the decision making for selection of best antenna pairs for specific (V2X) services.

• In case of centralized decisions, signaling from the network device to notify involved mobile devices for selection (or update) of appropriate antenna sets and required configuration for transmission and reception.

• In case of centralized decisions, network-based scheduling procedures to allocate resources in a multi-link and multi-antenna communication between mobile devices by using standard measurements.

• In case of de-centralized decisions, signaling among the mobile devices to select (or update) appropriate antenna sets and required configuration for transmission and reception.

The present invention generally provides a simple low-complexity approach to select the best subset of antennas in transmission and reception based on context information to improve e.g. SISO/MIMO V2X. The advantages offered are generally the following:

• Increase of reliability and availability of provided communication services through antenna selection and multi-link establishment. • Avoidance of looking for orthogonal pilot sequences for all the antennas of nearby mobile devices.

• Avoidance of exchanging a high number of pilots among vehicles to estimate the channel from all the transmit to receive antennas,

• No performance degradation due to mobility.

• No high complexity solution to select the best antennas, over which MIMO should be implemented.

A first aspect of the present invention provides a mobile device for wireless communications, the mobile device comprising more than one antenna and being configured to transmit capability information to a network device and/or another mobile device, the capability information including: an indication regarding the capability of the mobile device to communicate using multiple antennas, an antenna characteristic of at least one of the multiple antennas.

For example, the antenna characteristics may comprise a number of antenna elements, the antennas’ location, frequency dependent parameters, radiation pattern, a vehicle type (e.g., bus, van), a location of a vehicle, etc.

By transmitting the capability information to the network device and/or other mobile device, the selection of an antenna set for the communication between the mobile device of the first aspect and the other mobile device supported. The selection of the antenna set can be carried out either at the network device or in a cooperative manner between at least the mobile device and the other mobile device. By means of specifically the provided antenna characteristics, the set of antennas can be selected such that improved communications in terms of reliability capacity and latency are achieved.

In an implementation form of the first aspect, the mobile device is configured to transmit the capability information in a control plane message and/or in an application layer message to the network device and/or to the other mobile device.

A control plane message comprises, in particular, a Radio Control User Equipment Information Message, similar to the Radio Resource Control User Equipment (RRC UE) Capability Information message in LTE. An application layer message comprises, in particular, a Cooperative Awareness Message (CAM). Please note that from this point and onwards the Radio Control Protocol, which has a functionality similar to that of Radio Resource Control Protocol of LTE, and the latter will be used interchangeably.

In a further implementation form of the first aspect, the mobile device is further configured to transmit support information to the network device and/or the other mobile device, the support information including at least one of: a radio condition and/or network condition, an environment condition, particularly a road environment condition.

This improves the selection of the best antenna set for the wireless communication, particularly taking into account the current environment of the mobile devices communicating.

In a further implementation form of the first aspect, the mobile device is further configured to transmit support information to the network device and/or the other mobile device, the support information including at least one of: an orientation and/or relative position of at least one other mobile device, in particular with respect to the mobile device, a direction of movement and/or speed and/or estimated short-term path of at least one other mobile device.

These parameters help selecting the correct (best) antennas from the multiple antennas of the mobile device for communicating with the other mobile device.

In a further implementation form of the first aspect, the mobile device is further configured to transmit support information to the network device and/or the other mobile device, the support information including at least one of: a type of service and/or a transmission mode (e.g., multicast, unicast, broadcast), a service duration, service periodicity and/or service characteristic.

This further improves the selection of the antenna set.

In a further implementation form of the first aspect, the mobile device is further configured to transmit the support information in one of the following manners: on demand from an external device, in particular a network device and/or another mobile device; without demand, in particular a connection request message; periodically, in particular a measurement report.

The support information can be sent in one or more of: an Uplink and/or a downlink control plane message; a Sidelink control plane message; a Dynamic Reporting message.

For example, an RRC Connection Process message and/or a Non-Access Stratum, NAS, Service Request Information message, and/or RRC Sidelink UE Information message.

In a further implementation form of the first aspect, the mobile device is further configured to determine an antenna set, in particular for usage by the mobile device for communicating with the other mobile device, in particular based on a received capability information and/or support information from the other mobile device, and transmit information regarding the determined antenna set to said other mobile device.

In this way, the mobile device can determine the antenna set without help of the network. The transmission can be part of the transmission of the capability information as defined in the first aspect as such. An antenna set can comprise antenna configuration for the mobile device and/or for other mobile devices. The determination of the antenna set could involve two communicating mobile devices or a group of mobile devices.

In a further implementation form of the first aspect, the mobile device is configured to transmit the information regarding the determined antenna set in a control plane sidelink message, in particular in at least one of a: SCI message, Sidelink UE-to-UE Information message, RRC-like Sidelink message.

In a further implementation form of the first aspect, the mobile device is further configured to allocate a set of resources for communication with the other mobile device using the determined antenna set.

Both devices can use these resources for communication with the defined antenna set. The communication between the mobile devices is significantly improved in terms of reliability, capacity and latency. In a further implementation form of the first aspect, the mobile device is further configured to receive information comprising an antenna set to be used for communicating with another mobile device from the network device and/or another mobile device, in particular the another mobile device.

The information on the antenna set can comprise information for its own antennas regarding which antennas should be used for the communication with the other mobile device. And it can comprise information of one or more antennas from the other device that should be used to configure the transmission, in particular to configure the beam pointing, etc.

In a further implementation form of the first aspect, the determination of the antenna set can be performed according to one or more of the following manners: according to a pre defined rule; upon a request by another mobile device and/or a network device; repeatedly, in particular based on a channel measurement.

A second aspect of the present invention provides a network device for mobile communications, the network device being configured to receive capability information from a mobile device, the capability information including: an indication regarding a capability of the mobile device to communicate using multiple antennas, an antenna characteristic of at least one of the multiple antennas of the mobile device, determine an antenna set to be used by the mobile device for communicating with another mobile device based on the received capability information, and transmit information about the antenna set to the mobile device.

The network device can determine the antenna set based on the received information such that communication between the mobile device and the other mobile device is significantly improved, particularly with respect to reliability, capacity and latency, using the determined antennas.

The antenna set may include one of the following:

a) One or more Tx antennas of a transmitting mobile device for communicating with a group or a specific receiving mobile device. b) One or more Tx antennas and Rx antennas of a transmitting mobile device for communication with a group or a specific receiving mobile device.

c) One or more Tx antennas of a transmitting mobile device and one or more Rx antennas of one or more receiving mobile devices.

d) One or more Tx antennas and Rx antennas for a group of mobile device that participate to a service.

In an implementation form of the second aspect, the network device is further configured to notify the determined antenna set to the mobile device and optionally to the other mobile device.

This improves the communication between the mobile devices.

In a further implementation form of the second aspect, the network device is configured to notify the determined antenna set in a control plane message, in particular at least one of a: Radio Resource Control message or any Radio Control message, Downlink Control Information, DCI, message and/or Sidelink Control Information, SCI, message.

In a further implementation form of the second aspect, the network device is configured to receive support information from the mobile device in one of the following manners: on demand from an external device, in particular a network device and/or another mobile device; without demand, in particular a connection request message; periodically, in particular measurement report.

The support information can include at least one of: a radio condition and/or network condition; an environment condition, particularly a road environment condition; an orientation and/or relative position of at least one other mobile device with respect to the mobile device; a direction of movement and/or speed and/or estimated short-term path of at least one other mobile device; a type of service and/or a transmission mode; a service duration, service periodicity and/or service characteristic.

In a further implementation form of the second aspect, the network device is configured to additionally base the determination of the antenna set on the support information. That means, the network device is configured to determine the antenna set based on the capability information and the support information. This significantly improves the determination of the best antenna set.

In a further implementation form of second aspect, the determination of the antenna set can be performed according to one or more of the following manners: according to a pre defined rule; upon a request by another mobile device and/or a further network device; repeatedly, in particular based on a channel measurement.

In a further implementation form of the second aspect, the network device is configured to disseminate the support information received from the mobile device to one or more other mobile devices.

In a further implementation form of the second aspect, the network device is configured to allocate a set of resources for communication of the mobile device with the other mobile device using the determined antenna set.

In a further implementation form of the second aspect, the network device is configured to allocate a first subset of the set of resources to a first subset of the antenna set and allocate a second subset of the set of resources to a second subset of the antenna set.

In a further implementation form of the second aspect, the network device is configured to transmit the allocated set and/or subsets of resources to the mobile device, particularly in a Downlink Control Information (DCI) message.

A third aspect of the present invention provides a method for a mobile device, the method comprising signaling capability information to a network device and/or another mobile device, the capability information including: an indication regarding the capability of the mobile device to communicate using multiple antennas, an antenna characteristic of at least one of the multiple antennas.

In an implementation form of the third aspect, the method comprises transmitting the capability information in a control plane message and/or in an application layer message to the network device and/or to the other mobile device. In a further implementation form of the third aspect, the method comprises transmitting support information to the network device and/or the other mobile device, the support information including at least one of: a radio condition and/or network condition, an environment condition, particularly a road environment condition.

In a further implementation form of the third aspect, the method comprises transmitting support information to the network device and/or the other mobile device, the support information including at least one of: an orientation and/or relative position of at least one other mobile device, in particular with respect to the mobile device, a direction of movement and/or speed and/or estimated short-term path of at least one other mobile device.

In a further implementation form of the third aspect, the method comprises transmitting support information to the network device and/or the other mobile device, the support information including at least one of: a type of service and/or a transmission mode, a service duration, service periodicity and/or service characteristic.

In a further implementation form of the third aspect, the method comprises transmitting the support information in one of the following manners: on demand from an external device, in particular a network device and/or another mobile device; without demand, in particular a connection request message; periodically, in particular a measurement report.

In a further implementation form of the third aspect, the method comprises determining an antenna set, in particular for usage by the mobile device for communicating with the other mobile device, in particular based on a received capability information and/or support information from the other mobile device, and transmit information regarding the determined antenna set to said other mobile device.

In a further implementation form of the third aspect, the method comprises transmitting the information regarding the determined antenna set in a control plane sidelink message, in particular in at least one of a: SCI message, Sidelink UE-to-UE Information message, RRC- like Sidelink message. In a further implementation form of the third aspect, the method comprises allocating a set of resources for communication with the other mobile device using the determined antenna set.

In a further implementation form of the third aspect, the method comprises receiving information comprising an antenna set to be used for communicating with another mobile device from the network device and/or another mobile device, in particular the another mobile device.

In a further implementation form of the third aspect, the determination of the antenna set can be performed according to one or more of the following manners: according to a pre defined rule; upon a request by another mobile device and/or a network device; repeatedly, in particular based on a channel measurement.

A fourth aspect of the present invention provides a method for network device, the method comprising receiving capability information from a mobile device, the capability information including: an indication regarding a capability of the mobile device to communicate using multiple antennas, an antenna characteristic of at least one of the multiple antennas of the mobile device, determine an antenna set to be used by the mobile device for communicating with another mobile device based on the received capability information.

In an implementation form of the fourth aspect, the method comprises notifying the determined antenna set to the mobile device and optionally to the other mobile device.

In a further implementation form of the fourth aspect, the method comprises notifying the determined antenna set in set in a control plane message, in particular at least one of a: RRC Connection Reconfiguration message, Downlink Control Information, DCI, message and/or Sidelink Control Information, SCI, message.

In a further implementation form of the fourth aspect, the method comprises receiving support information from the mobile device in one of the following manners: on demand from an external device, in particular a network device and/or another mobile device; without demand, in particular a connection request message; periodically, in particular measurement report.

In a further implementation form of the fourth aspect, the method comprises additionally basing the determination of the antenna set on the support information.

In a further implementation form of the fourth aspect, the determination of the antenna set can be performed according to one or more of the following manners: according to a pre defined rule; upon a request by another mobile device and/or a further network device; repeatedly, in particular based on a channel measurement.

In a further implementation form of the fourth aspect, the method comprises disseminating the support information received from the mobile device to one or more other mobile devices.

In a further implementation form of the fourth aspect, the method comprises allocating a set of resources for communication of the mobile device with the other mobile device using the determined antenna set.

In a further implementation form of the fourth aspect, the method comprises allocating a first subset of the set of resources to a first subset of the antenna set and allocate a second subset of the set of resources to a second subset of the antenna set.

In a further implementation form of the fourth aspect, the method comprises transmitting the allocated set and/or subsets of resources to the mobile device, particularly in a DCI message.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

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

FIG. 1 shows a mobile device according to an embodiment of the present invention.

FIG. 2 shows a network device according to an embodiment of the present invention.

FIG. 3 shows an exemplary decision-making process for antenna set selection at a network device according to an embodiment of the present invention. FIG. 4 shows exemplarily a message sequence chart for indication of multi-antenna capabilities in RRC.

FIG. 5 shows exemplarily a message sequence chart with options to report multi antenna context information from mobile devices.

FIG. 6 shows an exemplary configuration of context information reporting elements and periodicity.

FIG. 7 shows an initial antenna selection and update of antenna selection exemplarily using RRC-ConneetionReconfiguration.

FIG. 8 shows a dynamic antenna selection exemplarily using Scheduling Grant messages (DCI and SCI). FIG. 9 shows the use of DCI 5A bits for antenna selection.

FIG. 10 shows downlink signaling for dynamic antenna selection based on DCI.

FIG. 11 shows uplink signaling for dynamic antenna selection based on DCI.

FIG. 12 shows an example of cooperative antenna selection for transmission of messages from mobile devices (Vehicle 2 to Vehicle 1 and Vehicle 3) with signaling.

FIG. 13 Notification of antenna selection using SCI.

FIG. 14 shows a signaling to setup signaling radio bearer 3.

FIG. 15 shows exemplary antenna selection fields for configuration using

SidelinkUEtoUEInformation.

FIG. 16 shows a method according to an embodiment of the present invention.

FIG. 17 shows a method according to an embodiment of the present invention.

FIG. 18 shows an overview of a conventional sidelink communication scenario, which exploits the diversity of the multi-antenna links.

DETAIFED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a mobile device 100 comprising more than one antenna 101 according to an embodiment of the present invention. The mobile device 100 is configured for wireless communications, for instance, with a network device 110 and/or another mobile device 100 (which may have the same capabilities as the device 100). The mobile device 100 may for instance be a UE and/or provided at a vehicle. In the latter case, it can communicate wirelessly (V2V) with the other mobile device 100, provided at another vehicle. Generally, the mobile device 100 can be configured for V2X communications. According to the invention, the mobile device 100 is configured to transmit capability information 102 to the network device 110 and/or to the other mobile device 100. This capability information 102 includes at least an indication 103 regarding the capability of the mobile device 100 to communicate using multiple antennas 101, and at least one antenna characteristic 104 of at least one of the multiple antennas 101 of the mobile device 100.

FIG. 2 shows accordingly a network device 110 according to an embodiment of the present invention. The network device 110 is configured for wireless communications, for instance, with the mobile device 100 and/or the other mobile device 100. The network device 110 may for instance be a BS or other network access node. The network device 110 can communicate wirelessly with the mobile devices 100, provided e.g. at vehicles. The network device 110 may be configured for Cellular Intelligent Transport Systems (C-TSI) communications.

According to the invention, the network device 110 is configured to transmit capability information 102 from a mobile device 100. This capability information 102 includes at least an indication 103 regarding a capability of the mobile device 100 to communicate using multiple antennas 101, and at least one antenna characteristic 104 of at least one of the multiple antennas 101 of the mobile device 100.

Further, the network device 100 is configured to determine an antenna set to be used by the mobile device 100 for communicating with another mobile device 100 based on the received capability information 102. The network device 100 is also configured to transmit information 200 about the antenna set to the mobile device 100.

In the above-described manner, the mobile device 100 shown in FIG. 1 and the network device 110 shown in FIG. 2 enable the selection of the antenna set out of the multiple antennas 101 of the mobile device 100 for a better (i.e. increased reliability and capacity and improved latency) wireless communication with the other mobile device 100 (or multiple other mobile devices 100).

The mobile device 100 and network device 110 shown in FIG. 1 and FIG. 2, respectively, can especially enhance V2V communications, allowing for multi-antenna selection, when using the sidelink between mobile device 100 at one vehicle and the other mobile device 100 at another vehicle. Both network-based (mode 3 in LTE standard) and autonomous (mode 4 in LTE standard) multi-antenna resource control and allocation can thereby be considered.

The solution of the present invention - based on the mobile device 100 and the network device 110 - includes not only the antenna set selection and the associated signaling by the mobile device 100 to inform the network device 110 about the multi-antenna communication capabilities 103 and the antenna characteristics 104 of the multiple antennas 101, but also signaling of e.g. (vehicle) context information for the further support of the selection of the best antenna set, or signaling that notifies the mobile device 100 about the selection or any update in the selected antenna set. Further, the invention also includes scheduling procedures to allocate resources in such a use case scenario, particularly by using e.g. standard measurements.

FIG 3 shows an overview of various exemplary steps for a network-based decision making process at a network device 110, when one or more mobile devices 100 of request multi antenna V2V communications for a specific V2X service. Upon receiving the request, the network device 110 can identify antennas 101 supported by the involved vehicles (i.e. mobile devices 100). Then, the network device 110 may check the service requirements of V2X. Then, the network device 110 may check road environment conditions (e.g. intersections, obstacles) and relative positions between the mobile devices 100. The network device 110 may also check radio conditions. Finally, the network device 110 is configured to decide on the antenna set to be used for specific V2X service by the involved vehicles 100. This decision may be taken at e.g. a BS, a core network entity or a cloud server as the network device 110.

In the following, more details on the informing of the network device 110 about the capability of the mobile device 100 to communicate using multiple antennas 101 are described.

As shown in FIG. 4, the mobile device 100 (vehicle) may inform the network device 110 (BS) about its capability 103 to communicate using multiple antennas 101 and their characteristics 103 by, for instance, extending the RRC UE Capabilitylnformation message with new fields. This capability information 102 may be sent during initial attachment process or on demand by the network device 110 (RRC UE Capability Enquiry) or need for update (e.g., if an antenna on the vehicle bumper is affected by some collision, event- based).

The information to be indicated through the MultiantennaCapability field, proposed in this invention, may be the following: number of placed antennas 101, location of antennas 101, frequency dependent characteristics (frequency range, radiation pattern, etc.), gain and vehicle class plus type indication (e.g., truck, van, bus, etc.). The fact that the vehicle 100 supports antenna selection may be indicated by the presence of the MultiantennaCapability field in the UECapabilitylnformation message.

Next, a signaling by the mobile device 100 to support the selection of the antenna set by the network device 110 is described in more detail.

In particular, context information may be provided from the mobile device 100 (or plurality of mobile devices 100), e.g. located at different vehicles, to the network device 110, in order to support the decision making for the selection of best antenna set, e.g. for specific V2X services. Two different options are considered: a) information provision together with specific service or connection requests for V2V communication among two or a group of mobile devices 100; and b) periodic reporting or event-driven update of context information from the mobile devices 100 to the network device 110.

FIG. 5 illustrates exemplary signaling steps for the two options for multi-antenna context information reporting by the mobile device 100 (vehicle). This reporting may be provided to a BS, a Core Network entity or an application server (e.g., cloud server) controlled by a network operator or a third party as the network device 110.

In both options, it is proposed to include a new Multi- antennaContextlnformation field that is used for the static or dynamic selection of a set of antennas (one or more antennas) to be used in a transmission/reception of data from/to the vehicle 100, and includes the following (sub-)elements not excluding additional ones: • Location of transmit and receive vehicles, orientation or relative positions among vehicles 100: position (x, y, z - UTM + altitude), direction of movement, speed, short-term path of vehicle 100.

• Road environment conditions (e.g., surrounding elements such as vehicles, buildings, bridges, etc., the orography of the surrounding terrain)

• Service layer Information: type of service, needed transmission modes (e.g., platooning service, multicast, etc.), service duration, periodicity and characteristics of the messages to be sent.

• Radio/Network conditions. Two possible examples: report of total power measured by each antenna or report of Channel Busy Ratio (CBR) measured by each antenna.

The periodic or event-driven reporting of the context information can be configured by the network device 110, either with the RRC Connection Reconfiguration message or with new dedicated messages. For event-driven reporting, the criteria for triggering the context update and the required content could be provided by the network device 110, could be fixed beforehand, or could be fixed by default and modified by the network device 110. Possible criteria for reporting of location could be a change of position by“x” meters, a change of direction of movement“x” degrees or a change of speed“x” m/s. The criterion for reporting of road environment conditions could be e.g. the appearance or disappearance of an obstacle in one communication path of the vehicle 100 (e.g. the path between one antenna and one intended receiver).

For periodic reporting elements to report and the periodicity of reports can be configured as in FIG. 6 between the mobile device 100 (vehicle) and the network device 110 (BS).

Further, more details on the notification of the antenna selection to the involved mobile devices 100 are now described.

Once the antenna set selection has been decided by the network device 110, the next step is to notify involved mobile devices 100 (here exemplarily each provided at a vehicle) for selection (or update) of appropriate antenna sets and required configuration for transmission and reception. The network device 110 (e.g. here a BS) will be in charge of configuring statically or dynamically the antenna selection for vehicle’s transmission/reception. For the initial antenna selection, it is proposed to extend the RRC_Connection_Reeonfiguration message to assign certain antenna set for a specific service among group of involved vehicles 100. The transmitting and/or receiving antennas could be selected for each V2X service, for instance, through the field sl-V2X- ConfigDedicatecl, as shown in FIG. 7. The new fields for the sl-V2X-ConfigDedicated element may be:

• Transmit antenna selection bitmap with fixed size to MAX_NB_V2X_ANTENNAS (0=not selected, l=selected)

• Receive antenna selection bitmap with fixed size to MAX_NB_V2X_ANTENNAS (0=not selected, l=selected)

When updates about the initial allocation are needed, due to the change of context or radio/service/road conditions (Dynamic Antenna Selection), there are two options: a) through updated RRC_Connection_Reeonfiguration messages (as described above) or b) through the Scheduling Grant messages (e.g., DCI and SCI).

For the second option, Downlink Control Information (DCI) and Sidelink Control Information (SCI) messages can be extended to assign to a transmitting mobile device 100 or inform a receiving mobile device 100 of the antenna set (one or more antennas of the multiple antennas 101 of the transmitting device 100) to be used in a more dynamic way.

In FIG. 8 it can be observed that, for sidelink, a new version of DCI 5A may be used to indicate the transmitting mobile device 100 (vehicle 1), which transmit antenna set to use and, possibly, the antenna set to be used by the receiving mobile device 100 (vehicle 2). Then, the sidelink transmitter uses the SCI with new fields to notify in sidelink to the receivers, which transmit antenna set is used and/or which reception antenna set should be used. This may require a new version of SCI.

DCI 5A maximum length is 32 bits. In case the information to be allocated is less than this, a padding with 0s may be applied. Generally, in a conventional transmission, 23 bits are used, meaning that 9 bits are free of use. Instead of encoding directly the TXAntennaSelection and the RXAntennaSelection, it is proposed to indicate the index of the configuration, TXAntennaSelection and RXAntennaSelection sequences signaled in the last RRCConnectionReconfiguration message for the specific sidelink transmission indicated in the DCI old fields. An example of this antenna encoding is shown in FIG. 9.

The remaining 9 bits could be alternatively separated e.g. into two parts: First e.g. 1 bit to indicate if there are two simultaneous transmissions. This allows diversity to be applicable in the sidelink transmission. Remaining 8 bits to encode two pairs of group selection (4 bits each).

Regarding the update of the DCI Format 5A (see original contents in TS 36.212), the new version (DCI 5AU) may have the following new fields allocated in 9 bits: use of diversity option (0 without diversity, 1 with diversity) and an indicator of the transmit and receive selection pair with fixed size to 8 bits (if diversity equal to 0) or twice 4 bits (if diversity equal to 1).

Note that an alternative option would be to have a table of TX-RX antenna pair options in (like the Modulation and Coding Scheme (MCS) table) and directly signal it in the RRCConnectionReconfiguration or in the DCI the right entry in the table. As an example, RRC signaling could be used to identify a subset (of TX-RX antenna pairs for each transmitter and receiver) and DCI a specific value in this subset.

Once the transmitting mobile device 100 is informed about the decision of the network device 110 with respect to transmit and receive antennas, for a group of communicating mobile devices 100, it has to inform also the destination mobile device 100 about this antenna selection. This could be made through signaling from the network device 110 to the destination mobile devices 100 or through signaling between the mobile devices 100 (e.g. vehicles) using the network device 110 to signal also to the destination mobile devices about the antenna selection and configuration in reception, or via the extension of already existing indicators. In this latter case, SCI is the appropriate message with the respective extensions. Again, the idea is to use the bits that are currently padded to embed there the required information. The SCI format 1 update (see original contents in TS 36.212) would have the following new fields for resource reservation using the only 4 remaining bits, although an extension for multi-antenna operation may be proposed: option 1) receive antenna selection bitmap with fixed size to MAX_NB_ ANTENNAS (0=not selected, l=selected) or option 2) include the destination ID and TRX and RXAntennaSelection data, i.e. the antenna selection bitmap for that destination.

Alternatively, the antenna selection could be performed even for cellular downlink (DL) or uplink (UL) communications. In these cases, the signaling based on DCI would be different. In particular, for DL, to notify the DL receiver which reception antenna set to use, DCIs 1, IX, 2 and 2X should be modified to include antenna group selection fields (see FIG. 10).

For UL, in order to indicate to the UL transmitter which transmit antenna set to use, DCIs 0 and 4 may be modified to include antenna group selection fields (see FIG 11).

In the following, network-based scheduling procedures to allocate resources in a multi-link and multi-antenna V2V communication are described in more detail.

The scheduling grants contained in DCI Format 5A may be used to allocate resources and can be also used in a multi-antenna configuration when all the antennas use the same set of resources. However, if the goal is to allocate different sets of resources to different sets of antennas, two options are possible:

• A new DCI defined as an array of DCI 5AU, with as many elements as sets of antennas are to be differentiated.

• Multiple DCI 5AU could be sent to a mobile device 100 in a subframe, each one with a different set of selected antennas, the mobile device 100 should be capable to receive multiple DCIs simultaneously.

According to 3GPP, it is not possible today to allocate resources explicitly to a specific service, since scheduling grants do not have this information. In order to make such explicit allocation, two alternatives are proposed:

• DCI 5AU could be extended with the addition of a field with a service indicator.

• DCI 5AU could have an element (resource-antenna set) per each logical channel identified by the ProSe Per Packet Priority (PPPP) in order of decreasing priority. The last two capabilities could be further combined to allocate a specific set of resources to a specific set of antennas and a specific service. Regarding the measurements to make proper scheduling decisions, these could take into account as input information the same context information presented above to make multi antenna configuration decisions, such as the CBR or RSSI measurements. Note that different context information may need different periodicities (e.g. location will not change as quickly as CBR or RSSI).

In the following, wireless communications between mobile devices 100, particularly vehicle-based multi-antenna V2V communication, is described in more detail.

In contrast to what was described above, the antenna selection decision could be also made in an autonomous manner by the mobile devices 100 (in the following exemplarily vehicles). In this case, it is up to each vehicle 100 to select the most convenient antenna set for the transmission to any destination vehicle 100 or to a group of vehicles 100. Still, transmission decisions shall be shared with the other vehicles 100 so that they can use the same configuration for the return channel and also prepare themselves for the reception. There are two options with respect to this vehicle-based multi-antenna selection:

1. With network support:

• The vehicles 100 provide context information via the uplink interface to the network device 110 for collection purpose.

• The network device 110 disseminates context information to the vehicles 100.

• Multi-antenna selection does not take place at the network-side and consequently is not transferred to the vehicles 100 as in the network-based approach. Instead, vehicles 100 make the decision for antenna selection, based on the context information provided by the network device 110 about neighboring vehicles 100.

• The decision is communicated to the neighboring vehicles 100. 2. Out of coverage / without any network coordination:

• All the context information should be locally exchanged using the sidelink channel, for instance by using evolved application layer (CAM-like messages) or control plane messages with the context data.

• The decision making for antenna selection is taken by the vehicles 100 (in a distributed and/or cooperative manner) and is communicated to the neighboring vehicles 100.

In the following, vehicle-based antenna selection with network support is described in more detail. First, collection and dissemination of context information by the network device 110 is described.

In order to support the selection of antenna set, is proposed that all the vehicles 100 send the context information to a geo-server. Thus, the“reflector” server shall include a geo server to be able to identify those vehicles 100 that are in the relevance area of every single vehicle 100, to which the information is to be transmitted.

Although the mechanisms described for the network-based solution are still valid to report context information from vehicles to the network device 110, the idea is that now the decision on the best antenna/connectivity solution is made by each vehicle 100 with the context information of the vehicles 100 around it. Therefore, a new mechanism must be designed to disseminate the context information relevant to a certain vehicle 100.

The requirements for this purpose are: Knowledge of vehicle’s position, knowledge of vehicles’ IDs whose context information is relevant, generation of a message with aggregated context information from relevant vehicles.

For the dissemination of context information from the network device 110, two options are could be used:

1. Use an application layer procedure (similar to the LTE Positioning Protocol (LPP)).

In this case, a downlink message similar to the Assistance Data message could be used to distribute the context information about other neighboring vehicles 100. Alternatively, a V2X server (e.g., the V 1 interface in LTE) or a V2X control function (e.g., the V3 interface in LTE) to collect and disseminate context information. In this case, the location of the mobile device is needed to filter relevant information and create the aggregated context information.

2. Use control plane messages at the radio level (or control plane messages from core network functions that are sent via the radio interface) to distribute the aggregated context information from other near vehicles 100.

A combination with standard procedures of LPP (LTE Positioning Protocol) could be proposed for the local dissemination of context information, since the vehicle location is needed to filter relevant information and create the aggregated message. The Assistance Data in LPP could be extended to include in the exchanged information the contextual data from neighbor vehicles.

Alternatively, edge computing could be used, by placing the functions for collection of dissemination of context information from the network device, close or at the BS.

In addition, all vehicles 100 could be in “promiscuous mode” so as to listen the transmission of sidelink data from nearby vehicles 100 and analyze the received signal power. This provides a measure of the coverage map from all the other vehicles. In fact, the analysis of the received signal power from the different antennas could also help locating the other vehicles’ position. In case a vehicle 100 is silent (without being active in any service) it shall send a kind of beacon data periodically so as to allow other to detect its presence and know its coverage map. In the end, the information taken from the analysis of nearby transmission will be added to the contextual Information received from the network.

Now, vehicle-based antenna selection decision making is described in more detail. Once the contextual information is shared by the different entities, there are different alternatives of how the antenna selection decision could be made. Either decisions on antenna selection could be made a) by each vehicle 100 in an isolated manner or b) they could be made in a cooperative manner. In a cooperative way that all vehicles 100 share their decision (triple Layer2-Id/TRXAntennaSelection/RXAntennaSelection) with the nearby vehicle 100 or within a cluster of cooperation to guarantee reciprocity in the selected transmission. In the latter, every triple allocation could have a confidence value associated with it, in such a way that if the other pair in the communication makes a different proposal with higher confidence, a vehicle could change its decision and assess the performance of the other alternative. In this sense, every triple decision could increase or decrease its confidence according to the experience transmission. In case of failure of the communication, the confidence on that selection would be reduced and vice versa.

In the example of FIG. 12, mobile device 100 (Vehicle 1) would change its proposal for antenna selection since the other mobile device 100 (Vehicle 2) is giving more confidence to the use of mirror antennas than to the bumpers. This assumes confidence factors given by each vehicle 100 to range e.g. from 0 (lowest confidence) to 9 (highest confidence).

Next, notification of antenna selection to involved vehicles 100 is described in more detail. Similarly as in the network-based antenna selection, protocols to notify involved vehicles 100 for selection (or update) of appropriate antenna sets and required configuration for transmission and reception are necessary. For this purpose, SCI with the respective extensions can be used to notify to the receivers in sidelink which transmit antenna set is used and/or which reception antenna set should be used for the reception of the information transmitted (see FIG. 12). Alternatively, for avoiding to modify the existing SCI, a new dedicated sidelink control-plane message could be used.

In the following, vehicle-based antenna selection without network support is described in more detail. When there is no network support for the antenna selection, vehicles 100 should be able to locally broadcast all their context information and their capabilities. One approach is to use modified CAM-like messages, in such a way that all information described before is included in the header or in the payload of an application layer message. Another proposal is to introduce an RRC-like protocol (control plane) for the radio signaling exchange of contextual information among vehicles.

If the option with modified CAM-like messages is considered, the protocols to notify involved vehicles for selection (or update) of appropriate antenna sets and required configuration for transmission and reception are those already described. If, otherwise, an RRC protocol is considered (e.g.,“light” RRC protocol), it could further simplify the notification phase. Regarding the“light” RRC protocol, we propose the establishment of a new SRB3 (signaling radio bearer 3) to be used for V2X signaling exchange (see FIG. 14). After the sidelink discovery phase, both extremes in the V2X link shall pair with a simple procedure.

No new ciphering keys may apply, but simply the same used for the sidelink transmission. Once the logical channel associated to the SRB3 have been identified, it will be used to send valid information associated with the context exchange needed for the multi-antenna and resource selection. As in the previous section, the promiscuous mode in vehicles 100 will be used to calculate the received signal power from the nearby vehicles 100, so as to incorporate that information within own contextual data.

The context exchange may be carried out using a SidelinkUEtoUEInformation message including context information and a set of multi-antenna configuration alternatives that could then be indexed, e.g. with the SCI available bits (see FIG. 15).

Regarding the dynamic antenna selection using SCI, the remaining 4 bits could be used to index the configuration to be used in the subsequent transmission. Once a decision is made, it could be exchanged among vehicles so as to make a cooperative decision.

FIG. 16 shows a method 1600 according to an embodiment of the present invention. The method 1600 is for wireless communications, and is particularly for a mobile device 100, for instance as shown in FIG. 1. The method 1600 comprises a step 1601 of transmitting capability information 102 to a network device 110 and/or another mobile device 100, the capability information including: an indication 103 regarding the capability of the mobile device 100 to communicate using multiple antennas 101, an antenna characteristic or characteristics of, at least, one of the multiple antennas 101.

FIG. 17 shows the method 1700 according to an embodiment of the present invention. The method 1700 is particularly for a network device 110. The method 1700 comprises a step 1701 of receiving capability information 102 from a mobile device 100, the capability information 102 including: an indication 103 regarding a capability of the mobile device 100 to communicate using multiple antennas 101, an antenna characteristic or characteristics of, at least, one of the multiple antennas 101 of the mobile device 100. The method 1700 further comprises a step 1702 of determining an antenna set to be used by the mobile device 100 for communicating with another mobile device 110 based on the received capability information 102.

The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word“comprising” does not exclude other elements or steps and the indefinite article“a” or“an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

Claims

1. Mobile device (100) for wireless communications, the mobile device (100) comprising more than one antenna (101) and being configured to

transmit capability information (102) to a network device (110) and/or another mobile device (100), the capability information (102) including:

an indication (103) regarding the capability of the mobile device (100) to communicate using multiple antennas (101),

an antenna characteristic (104) of at least one of the multiple antennas (101).

2. Mobile device (200) according to claim 1, configured to

transmit the capability information (102) in a control plane message and/or in an application layer message to the network device (110) and/or to the other mobile device (100).

3. Mobile device (100) according to claim 1 or 2, further configured to

transmit support information to the network device (110) and/or to the other mobile device (100), the support information including at least one of:

a radio condition and/or network condition,

an environment condition, particularly a road environment condition.

4. Mobile device (100) according to one of the claims 1 to 3, further configured to transmit support information to the network device (110) and/or to the other mobile device (100), the support information including at least one of:

an orientation and/or relative position of at least one other mobile device (100), in particular with respect to the mobile device (100), a direction of movement and/or speed and/or estimated short-term path of at least one other mobile device (100).

5. Mobile device (100) according to one of the claims 1 to 4, further configured to transmit support information to the network device (110) and/or to the other mobile device (100), the support information including at least one of:

a type of service and/or a transmission mode, a service duration, service periodicity and/or service characteristic.

6. Mobile device (100) according to one of the claims 3 to 5, configured to

transmit the support information in one of the following manners:

- on demand from an external device, in particular from a network device (110) and/or another mobile device (100);

- without demand, in particular a connection request message;

- periodically, in particular a measurement report.

7. Mobile device (100) according to one of the claims 1 to 6, further configured to determine an antenna set, in particular for usage by the mobile device (100) for communicating with the other mobile device (100), in particular based on a received capability information (102) and/or support information from the other mobile device (100), and

transmit information regarding the determined antenna set to said other mobile device (100).

8. Mobile device (100) according to claim 7, configured to

transmit the information regarding the determined antenna set in a control plane sidelink message, in particular in at least one of a:

SCI message,

Sidelink UE-to-UE Information message,

Radio Resource Control message for Sidelink or any Radio Control messages for sidelink.

9. Mobile device (100) according to the preceding claim, further configured to

allocate a set of resources for communication with the other mobile device (100) using the determined antenna set.

10. Mobile device (100) according to one of the claims 1 to 9, configured to

receive information comprising an antenna set to be used for communicating with another mobile device (100) from the network device (110) and/or another mobile device (100), in particular the another mobile device (100).

11. Mobile device (100) according to one of the claims 7 to 10, wherein the determination of the antenna set can be performed according to one or more of the following manners:

- according to a pre-defined rule;

- upon a request by another mobile device and/or a network device (110);

- repeatedly, in particular based on a channel measurement.

12. Network device (110) for mobile communications, the network device (110) being configured to

receive capability information (102) from a mobile device (100), the capability information (102) including:

an indication (103) regarding a capability of the mobile device (100) to communicate using multiple antennas (101),

an antenna characteristic (104) of at least one of the multiple antennas (101) of the mobile device (100),

determine an antenna set to be used by the mobile device (100) for communicating with another mobile device (100) based on the received capability information (102), and transmit information (200) about the antenna set to the mobile device (100).

13. Network device (110) according to claim 12, further configured to

notify the determined antenna set to the mobile device (100) and optionally to the other mobile device (100).

14. Network device (110) according to claim 13, configured to

notify the determined antenna set in set in a control plane message, in particular at least one of a:

Radio Resource Control message or any Radio Control message.

Downlink Control Information, DCI, message and/or Sidelink Control Information, SCI, message.

15. Network device (110) according to one of the claims 12 or 14, configured to

receive support information from the mobile device (100) in one of the following manners: - on demand from an external device, in particular a network device and/or another mobile device (100);

- without demand, in particular a connection request message;

- periodically, in particular a measurement report.

16. Network device (110) according to the preceding claim, wherein the network device (110) is configured to additionally base the determination of the antenna set on the support information.

17. Network device (110) according to one of the preceding claims, wherein the determination of the antenna set can be performed according to one or more of the following manners:

- according to a pre-defined rule;

- upon a request by another mobile device (100) and/or a further network device

(HO);

- repeatedly, in particular based on a channel measurement.

18. Network device (110) according to one of the claims 15 to 17, configured to

disseminate the support information received from the mobile device (100) to one or more other mobile devices (100).

19. Network device (110) according to one of the claims 12 to 18, further configured to

allocate a set of resources for communication of the mobile device (100) with the other mobile device (100) using the determined antenna set.

20. Network device (110) according to claim 19, configured to

allocate a first subset of the set of resources to a first subset of the antenna set and allocate a second subset of the set of resources to a second subset of the antenna set.

21. Network device (110) according to claim 19 or 20, configured to

transmit the allocated set and/or subsets of resources to the mobile device (100), particularly in a DCI message.

22. Method (1600) for a mobile device (100), the method (1600) comprising transmitting (1601) capability information (102) to a network device (110) and/or another mobile device (100), the capability information including:

an antenna characteristic of at least one of the multiple antennas (101).

23. Method (1700) for a network device (110), the method (1700) comprising

receiving (1701) capability information (102) from a mobile device (100), the capability information (102) including:

an antenna characteristic of at least one of the multiple antennas (101) of the mobile device (100),

determining (1702) an antenna set to be used by the mobile device (100) for communicating with another mobile device (110) based on the received capability information (102).

24. System for wireless communications, the system comprising

a mobile device according to one of the claims 1 to 11, and

a network device according to one of the claims 12 to 21.