ENHANCED EXCEPTIONAL POOL DESIGN FOR NR V2X SIDELINK

Description

The present application relates to the field of wireless communication systems or networks, more specifically to approaches for a wireless communication among user devices of a wireless communication system using a sidelink communication, like a V2X communication. Embodiments concern improvements with regard to resource pools to be used for a sidelink communication among respective user devices.

Fig. 1 is a schematic representation of an example of a terrestrial wireless network 100 including, as is shown in Fig. 1 (a), a core network 102 and one or more radio access networks RAN ₁ , RAN ₂ , ... RAN _N . Fig. 1 (b) is a schematic representation of an example of a radio access network RAN _n that may include one or more base stations gNBi to gNB ₅ , each serving a specific area surrounding the base station schematically represented by respective cells 106i to 106 ₅ . The base stations are provided to serve users within a cell. The term base station, BS, refers to a gNB in 5G networks, an eNB in UMTS/LTE/LTE-A/ LTE-A Pro, or just a BS in other mobile communication standards. A user may be a stationary device or a mobile device. The wireless communication system may also be accessed by mobile or stationary loT devices which connect to a base station or to a user. The mobile devices or the loT devices may include physical devices, ground based vehicles, such as robots or cars, aerial vehicles, such as manned or unmanned aerial vehicles (UAVs), the latter also referred to as drones, buildings and other items or devices having embedded therein electronics, software, sensors, actuators, or the like as well as network connectivity that enables these devices to collect and exchange data across an existing network infrastructure. Fig. 1 (b) shows an exemplary view of five cells, however, the RANn may include more or less such cells, and RAN _n may also include only one base station. Fig. 1 (b) shows two users UEi and UE ₂ , also referred to as user equipment, UE, that are in cell 106 ₂ and that are served by base station gNB ₂ . Another user UE3 is shown in cell 106 ₄ which is served by base station gNB ₄ . The arrows IO8 ₁ , 108 ₂ and 108 ₃ schematically represent uplink/downlink connections for transmitting data from a user UEi, UE ₂ and UE ₃ to the base stations gNB ₂ , gNB ₄ or for transmitting data from the base stations gNB ₂ , gNB ₄ to the users UE-i , UE ₂ , UE ₃ . Further, Fig. 1 (b) shows two loT devices 110i and 110 ₂ in cell 1064, which may be stationary or mobile devices. The loT device 110i accesses the wireless communication system via the base station gNB ₄ to receive and transmit data as schematically represented by arrow 1 12i. The loT device 110 ₂ accesses the wireless communication system via the user UE3 as is schematically represented by arrow 1 12 ₂ . The respective base station gNBi to gNBs may be connected to the core network 102, e.g. via the S1 interface, via respective backhaul links 114i to 114 ₅ , which are schematically represented in Fig. 1 (b) by the arrows pointing to“core”. The core network 102 may be connected to one or more external networks. Further, some or all of the respective base station gNBi to gNBs may connected, e.g. via the S1 or X2 interface or the XN interface in NR, with each other via respective backhaul links 1 161 to 1 165, which are schematically represented in Fig. 1 (b) by the arrows pointing to“gNBs”.

For data transmission a physical resource grid may be used. The physical resource grid may comprise a set of resource elements to which various physical channels and physical signals are mapped. For example, the physical channels may include the physical downlink, uplink and sidelink shared channels (PDSCH, PUSCH, PSSCH) carrying user specific data, also referred to as downlink, uplink and sidelink payload data, the physical broadcast channel (PBCH) carrying for example a master information block (MIB) and a system information block (SIB), the physical downlink, uplink and sidelink control channels (PDCCH, PUCCH, PSSCH) carrying for example the downlink control information (DCI), the uplink control information (UCI) and the sidelink control information (SCI). For the uplink, the physical channels may further include the physical random access channel (PRACH or RACH) used by UEs for accessing the network once a UE synchronized and obtained the MIB and SIB. The physical signals may comprise reference signals or symbols (RS), synchronization signals and the like. The resource grid may comprise a frame or radio frame having a certain duration in the time domain and having a given bandwidth in the frequency domain. The frame may have a certain number of subframes of a predefined length, e.g. 1 ms. Each subframe may include one or more slots of 12 or 14 OFDM symbols depending on the cyclic prefix (CP) length. A frame may also consist of a smaller number of OFDM symbols, e.g. when utilizing shortened transmission time intervals (sTTI) or a mini-slot/nonslot-based frame structure comprising just a few OFDM symbols.

The wireless communication system may be any single-tone or multicarrier system using frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, e.g. DFT-s-OFDM. Other waveforms, like non- orthogonal waveforms for multiple access, e.g. filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) or universal filtered multi carrier (UFMC), may be used. The wireless communication system may operate, e.g., in accordance with the LTE- Advanced pro standard or the 5G or NR, New Radio, standard.

The wireless network or communication system depicted in Fig. 1 may by a heterogeneous network having distinct overlaid networks, e.g., a network of macro cells with each macro cell including a macro base station, like base station gNBi to gNBs, and a network of small cell base stations (not shown in Fig. 1), like femto or pico base stations.

In addition to the above described terrestrial wireless network also non-terrestrial wireless communication networks exist including spaceborne transceivers, like satellites, and/or airborne transceivers, like unmanned aircraft systems. The non-terrestrial wireless communication network or system may operate in a similar way as the terrestrial system described above with reference to Fig. 1 , for example in accordance with the LTE-Advanced Pro standard or the 5G or NR, new radio, standard.

In mobile communication networks, for example in a network like that described above with reference to Fig. 1 , like an LTE or 5G/NR network, there may be UEs that communicate directly with each other over one or more sidelink (SL) channels, e.g., using the PC5 interface. UEs that communicate directly with each other over the sidelink may include vehicles communicating directly with other vehicles (V2V communication), vehicles communicating with other entities of the wireless communication network (V2X communication), for example roadside entities, like traffic lights, traffic signs, or pedestrians. Other UEs may not be vehicular related UEs and may comprise any of the above-mentioned devices. Such devices may also communicate directly with each other (D2D communication) using the SL channels.

When considering two UEs directly communicating with each other over the sidelink, both UEs may be served by the same base station so that the base station may provide sidelink resource allocation configuration or assistance for the UEs. For example, both UEs may be within the coverage area of a base station, like one of the base stations depicted in Fig. 1. This is referred to as an“in-coverage” scenario. Another scenario is referred to as an“out- of-coverage” scenario. It is noted that“out-of-coverage” does not mean that the two UEs are not within one of the cells depicted in Fig. 1 , rather, it means that these UEs

may not be connected to a base station, for example, they are not in an RRC connected state, so that the UEs do not receive from the base station any sidelink resource allocation configuration or assistance, and/or may be connected to the base station, but, for one or more reasons, the base station may not provide sidelink resource allocation configuration or assistance for the UEs, and/or

may be connected to the base station that may not support NR V2X services, e.g. GSM, UMTS, LTE base stations.

When considering two UEs directly communicating with each other over the sidelink, e.g. using the PC5 interface, one of the UEs may also be connected with a BS, and may relay information from the BS to the other UE via the sidelink interface. The relaying may be performed in the same frequency band (in-band-relay) or another frequency band (out-of- band relay) may be used. In the first case, communication on the Uu and on the sidelink may be decoupled using different time slots as in time division duplex, TDD, systems.

Fig. 2 is a schematic representation of an in-coverage scenario in which two UEs directly communicating with each other are both connected to a base station. The base station gNB has a coverage area that is schematically represented by the circle 200 which, basically, corresponds to the cell schematically represented in Fig. 1. The UEs directly communicating with each other include a first vehicle 202 and a second vehicle 204 both in the coverage area 200 of the base station gNB. Both vehicles 202, 204 are connected to the base station gNB and, in addition, they are connected directly with each other over the PC5 interface. The scheduling and/or interference management of the V2V traffic is assisted by the gNB via control signaling over the Uu interface, which is the radio interface between the base station and the UEs. In other words, the gNB provides SL resource allocation configuration or assistance for the UEs, and the gNB assigns the resources to be used for the V2V communication over the sidelink. This configuration is also referred to as a Mode 1 configuration in NR V2X or as a Mode 3 configuration in LTE V2X.

Fig. 3 is a schematic representation of an out-of-coverage scenario in which the UEs directly communicating with each other are either not connected to a base station, although they may be physically within a cell of a wireless communication network, or some or all of the UEs directly communicating with each other are to a base station but the base station does not provide for the SL resource allocation configuration or assistance. Three vehicles 206, 208 and 210 are shown directly communicating with each other over a sidelink, e.g., using the PC5 interface. The scheduling and/or interference management of the V2V traffic is based on algorithms implemented between the vehicles. This configuration is also referred to as a Mode 2 configuration in NR V2X or as a Mode 4 configuration in LTE V2X. As mentioned above, the scenario in Fig. 3 which is the out-of-coverage scenario does not necessarily mean that the respective Mode 2 UEs (in NR) or Mode 4 UEs (in LTE) are outside of the coverage 200 of a base station, rather, it means that the respective Mode 2 UEs (in NR) or Mode 4 UEs (in LTE) are not served by a base station, are not connected to the base station of the coverage area, or are connected to the base station but receive no SL resource allocation configuration or assistance from the base station. Thus, there may be situations in which, within the coverage area 200 shown in Fig. 2, in addition to the NR Mode 1 or LTE Mode 3 UEs 202, 204 also NR Mode 2 or LTE Mode 4 UEs 206, 208, 210 are present.

In the above-described scenarios of vehicular user devices, UEs, a plurality of such user devices may form a user device group, also referred to simply as group, and the communication within the group or among the group members may be performed via the sidelink interfaces between the user devices, like the PC5 interface. For example, the above-described scenarios using vehicular user devices may be employed in the field of the transport industry in which a plurality of vehicles being equipped with vehicular user devices may be grouped together, for example, by a remote driving application. Other use cases in which a plurality of user devices may be grouped together for a sidelink communication among each other include, for example, factory automation and electrical power distribution. In the case of factory automation, a plurality of mobile or stationary machines within a factory may be equipped with user devices and grouped together for a sidelink communication, for example for controlling the operation of the machine, like a motion control of a robot. In the case of electrical power distribution, entities within the power distribution grid may be equipped with respective user devices which, within a certain area of the system may be grouped together so as to communicate via a sidelink communication with each other so as to allow for monitoring the system and for dealing with power distribution grid failures and outages.

Naturally, in the above-mentioned use cases sidelink communication is not limited to a communication within a group. Rather, the sidelink communication may be among any of UEs, like any pair of UEs.

It is noted that the information in the above section is only for enhancing the understanding of the background of the invention and therefore it may contain information that does not form prior art that is already known to a person of ordinary skill in the art. Starting from a prior art as described above, there may be a need for improvements with regard to resource pools to be used for a sidelink communication among user devices, e.g., mobile user devices.

Embodiments of the present invention are now described in further detail with reference to the accompanying drawings:

Fig. 1 shows a schematic representation of an example of a wireless communication system;

Fig. 2 is a schematic representation of an in-coverage scenario in which UEs directly communicating with each other are connected to a base station;

Fig. 3 is a schematic representation of an out-of-coverage scenario in which UEs directly communicating with each other receive no SL resource allocation configuration or assistance from a base station;

Fig. 4 illustrates schematically an exceptional pool that spans a plurality of resource blocks in the frequency domain and a plurality of time slots in the time domain;

Fig. 5 illustrates an example of a V2X communication using an exceptional pool;

Fig. 6 is a schematic representation of a wireless communication system including a transmitter, like a base station, and one or more receivers, like user devices, UEs;

Fig. 7 illustrates schematically an embodiment of the inventive approach of providing a common resource pool for a sidelink communication among UEs;

Fig. 8 illustrates embodiments for implementing an exceptional pool for different cast- types;

Fig. 9 illustrates an example of a prioritization in an exceptional pool; and Fig. 10 illustrates an example of a computer system on which units or modules as well as the steps of the methods described in accordance with the inventive approach may execute.

Embodiments of the present invention are now described in more detail with reference to the accompanying drawings in which the same or similar elements have the same reference signs assigned.

In wireless communication systems or networks like those described above with reference to Fig. 1 , Fig. 2 or Fig. 3, a sidelink communication, like an LTE V2X communication may use an exceptional pool, also referred to as an exceptional set of sidelink resources, that is defined in addition to the common TX/RX resource pools for the LTE V2X communication. Fig. 4 illustrates schematically such an exceptional pool 220 that spans a plurality of resource blocks in the frequency domain and a plurality of time slots in the time domain. The exceptional resource pool 220 defines a number of resources or a set of resources that may be used by respective UEs that are served or are in coverage of a certain base station of the wireless communication network. The exceptional resource pool 220 provides resources for three UEs, namely for UE1 , UE2 and UE3. In a first number of time slots the three UEs equally share the resources in the frequency domain, in the center part a number of time slots and resource blocks are solely allocated to UE2, and in the last number of time slots a smaller part of the resource blocks is allocated to UE3 and a larger part of the resource blocks is allocated to UE1. As may already be derived from the name, the exceptional pool 220 is to be used in exceptional cases for a short period of time, for example, to ensure connectivity during a handover or to ensure reliability and/or latency, for example during transition phases. The exceptional pool 220 is used in case the one or more UEs are in coverage, i.e., for UEs that are controlled by the base station as discussed above with reference to Fig. 2.

In accordance with Reference [1], the exceptional pool for an LTE V2X communication may be used for the transition between pools, for example during an idle-to-connected situation, during a RRC reconfiguration situation, or during a handover situation. The way to select the resources when using the exceptional pool is as follows:

The RRC specification may include the exceptional pool in the system information block, like in the SIB21 , for non-handover cases, like the above-mentioned idle-to- connected case, a radio link failure, RLF, case and the above-mentioned RRC reconfiguration case. When provided by the serving cell, also referred to as the serving base station, i.e., the base station with which the UE is in coverage, a presensing on the exceptional pool may be performed.

In the handover case, the exceptional pool may be provided by the target cell, i.e., the cell or base station to which the UE tries to make connection responsive to detecting that it reaches the new cell. The UE may perform a random selection on this pool based on the concern that sensing may cause a latency issue in the transition stage.

Resources from the exceptional pool, like the commTxPoolExceptional, may be used when the UEs are assisted is in a transition between the RRCJDLE state and the RRC_CONNECTED state. For example, the UE may detect a radio link failure, RLF, which then causes an RRC connection re-establishment. In this case, the UE may have some time to select a suitable cell or base station to request an RRC connection re-establishment. The above-mentioned exceptional pool may be provided to be used during this transition or time period as so to improve the service continuity. The situation may be quite common for public safety UEs, for example, a fire fighter entering a building may frequently encounter such a situation and service continuity is extremely important.

Fig. 5 illustrates an example of a V2X communication using the above-described exceptional pool. Fig. 5 illustrates schematically two cells including respective base stations gNB1 and gNB2. Further, two user groups 220 and 224 are illustrated of which user group 220 includes UE1 , UE2 and UE3, while user group 224 includes UE4 and UE5. UE2 in group 220 may perform a group cast communication towards all users in group 224. The group cast communication may employ resources from the exceptional pool for gNB1. A unicast communication may be performed as well, and Fig. 5 illustrates an example in which UE5 performs a unicast communication to UE3 of group 222 using resources from the exceptional pool of the base station gNB2. For a frequency used for a V2X side link communication as illustrated in Fig. 5, the exceptional resource pool may be configured in a system information block, like SIB18 or SIB21 , also referred to as system information block type 18 or system information block type 21 . The exceptional resource pool may be configured in an RRC connection reconfiguration for the concerned frequency. The UE may be configured to use resource pools provided by RRC signaling for the concerned frequency of the serving cell or base station as indicated by RRC_IDLE/RRC_CONNECTED or by the RRC connection reconfiguration for the concerned frequency. For the V2X sidelink communication respective exceptional poo! RRC information elements may be provided, some of which are described below, namely the mobility control NR element as well as the above-mentioned system information blocks type 18 and type 21.

The mobility control information element is provided for the network control mobility and includes the commTxExceptional parameter as indicated in Reference [1] and as indicated below:

The SIBs include parameters needed to acquire exceptional pool parameters, and a UE may apply the system information acquisition procedure upon selecting, for example, upon power on, a cell, or upon re-selecting a cell, e.g., after a handover completion. The following information blocks include the exceptional pool information.

As explained above with reference to Fig. 5, in NR V2X communications both unicast and groupcast communications may be supported, in addition to a broadcast communication. Additionally, enhanced and more detailed quality of service, QoS, parameters, like PQI, may be introduced. Some NR use-cases may demand lower latency as well as higher reliability along with a higher data rate when compared to LTE cases. One example of a use case for a groupcast communication is the so called platooning, in accordance with which a plurality of mobile user devices, like vehicles, form a group. The platooning use case demands short inter-vehicular distances between the vehicles within the platoon and one of the main issues with platoon control is the latency during the wireless communications. Latency has a negative impact on the safety and may disrupt the stability of the platoon. Starting from Release 14, 3GPP focused on a V2V communication as an enabler for such a use case, as is described in reference [4] The exceptional pool concept was proposed to address communication discontinuity for V2V communication in instances of a regulating failure, a handover or another exceptional disruption of the communication. Since the LTE V2V communication is based on broadcasting, the exceptional pool was considered for data transmission. Cooperative short distance grouping is a scenario where the distance between the vehicles is extremely small and, in general, the inter-vehicular distance is around 0.3 seconds in a time scale, as indicated in reference [3]. This very close driving demands a highly reliable vehicle-to-vehicle communication that allows for a low latency transmission. In such a scenario, when, for example, a group of autonomously moving UEs passes across multiple cells, some of the UEs may cross the cell while other UEs are still within the cell which may result in interference among the vehicles. In other words, some group members may have already left the current cell while other group members are still within the cell.

In addition to the above-mentioned exceptional resource pools, each gNB of the wireless communication system provides for one or more of a sidelink TX pool, a sidelink RX pool or a sidelink TX/RX pool providing resources to be used by the UEs for the sidelink communication during the non-exceptional situations, for example during a normal communication from one UE to another UE within the cell over the sidelink.

The drawback of the above-summarized conventional approaches is that each cell or base station has its own resource sets or resource pools to be used for the sidelink communication, i.e., it has its own exceptional pool and its own exceptional TX/RX pools so that in a scenario as mentioned above, i.e., when some UEs of a group are already outside of a cell while other UEs remain within the cell, the UEs of the group may have allocated different resources associated with the different cells or base stations to be used for the communication. For example, in LTE, to keep service continuity, the exceptional pool mentioned above may be used during handover, HO. The exceptional pool configuration may be broadcast using the system information block, like the SIB type 21. However, in a groupcast scenario, a group of moving UEs, like the group members of a platoon, may be distributed among different cells. In such a scenario some group members may have already performed the handover to a new serving cell while the other group members are still served by the preceding cell or base station. In such a scenario, a vehicle in the serving cell and a vehicle in the target cell may interfere with other nearby vehicles in case they use the same exceptional pool of the target cell.

To avoid such situations and possible interferences the present invention provides various aspects for improving the sidelink communication among UEs avoiding, for example, the above-summarized problems regarding UE groups in which some group members are already in a new cell while other UE members are still in a preceding cell. In other words, the present invention addresses the above issues by providing several aspects for improving the sidelink communication among mobile users of a wireless communication network as is discussed in more detail below.

Embodiments of the present invention may be implemented in a wireless communication system as depicted in Fig. 1 , Fig. 2, and Fig. 3 including base stations and users, like mobile terminals or loT devices. Fig. 6 is a schematic representation of a wireless communication system including a transmitter 300, like a base station, and one or more receivers 302i to 302n, like user devices, UEs. The transmitter 300 and the receivers 302 may communicate via one or more wireless communication links or channels 304a, 304b, 304c, like a radio link. The transmitter 300 may include one or more antennas ANTT or an antenna array having a plurality of antenna elements, a signal processor 300a and a transceiver 300b, coupled with each other. The receivers 302 include one or more antennas ANTR or an antenna array having a plurality of antennas, a signal processor 302ai, 302a _n , and a transceiver 302bi, 302b _n coupled with each other. The base station 300 and the UEs 302 may communicate via respective first wireless communication links 304a and 304b, like a radio link using the Uu interface, while the UEs 302 may communicate with each other via a second wireless communication link 304c, like a radio link using the PC5 interface. The UEs may communicate with each other over the sidelink. The system, the one or more UEs 302 and the base stations may operate in accordance with the inventive teachings described herein.

WIRELESS COMMUNICATION SYSTEM

The present invention provides (see for example claim 1 ) a wireless communication system, comprising a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, wherein the wireless communication system is to provide a common set of sidelink resources, the common set of sidelink resources being • associated with or shared among two or more of a plurality of cells/base stations of the wireless communication system, or

• associated with a particular geographical area.

In accordance with embodiments (see for example claim 2), the common set of sidelink resources includes one or more of:

• a common TX resource set for a transmission over the sidelink,

• a common RX resource set for a reception over the sidelink,

• a common resource set for a transmission and reception over the sidelink,

• a common TX exceptional resource set for a transmission over the sidelink in case one or more certain situations are experienced within the wireless communication system,

• a common RX exceptional resource set for a reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and

• a common exceptional resource set for a transmission and reception over the sidelink in case one or more certain situations are experienced within the wireless communication system.

In accordance with embodiments (see for example claim 3), the one or more certain situations in which an exceptional resource set is used include one or more of:

• an idle-to-connected situation of one or more of the UEs,

• an RRC reconfiguration of one or more of the UEs, and

• a handover situation of one or more of the UEs,

• a radio link failure, RLF, and

• a radio link break.

In accordance with embodiments (see for example claim 4), the wireless communication system is to provide an indication of the two or more cells/base stations or of the particular geographical area for which the common set of sidelink resources is valid.

In accordance with embodiments (see for example claim 5), the wireless communication system is to provide the indication in • a System Information Block, SIB, the SIB including an information element, IE, e.g., the SystemlnformationBlockTypeX, and the IE including the indication, e.g., a parameter areaScope, of the valid common set of sidelink resources, or

• a configuration IE, e.g., the IE SL-V2X-UE-ConfigList, the configuration IE further indication an inter-frequency resource configuration per-carrier or per-cell or per validity area.

In accordance with embodiments (see for example claim 6), the wireless communication system comprises a plurality of base stations, the plurality of base stations including at least a first base station and a second base station, the wireless communication system comprises an interface, like the X2 or Xn interface, the interface interconnecting the first base station and the second base station, the first or source base station is to transfer, using for example a X2 or Xn SETUP REQUEST message, to the second or candidate base station an indication of the common set of sidelink resources, and the candidate base station is to replace a set of sidelink resources existing at the candidate base station by the common set of sidelink resources, wherein the candidate base station may optionally acknowledge or not acknowledge, using for example a X2 or Xn SETUP RESPONSE message, the indication of the common set of sidelink resources.

In accordance with embodiments (see for example claim 7),

• the first base station and the second base station use the same radio access technology, RAT, like NR or E-UTRA, or

• the first base station uses a first RAT, like NR, and the second base station uses a second, different RAT, like E-UTRA.

In accordance with embodiments (see for example claim 8), the wireless communication system comprises a plurality of base stations, the plurality of base stations including at least a first base station and a second base station, the first base station using a first RAT, like NR, and the second base station using a second, different RAT, like E-UTRA, and the first base station and the second base station sharing the spectrum and having fully or partially overlapping coverages or coverage areas, the wireless communication system comprises an interface, like the X2 or Xn interface, the interface interconnecting the first base station and the second base station, and the wireless communication system is to use a resource coordination procedure over the interface to enable the first base station and the second base station to configure a part of the shared spectrum as the common set of sidelink resources.

In accordance with embodiments (see for example claim 9), the first base station is to initiate the resource coordination procedure by sending a message, like the E-UTRA - NR CELL RESOURCE COORDINATION REQUEST message, to the second base station over the interface, the message including a Data Traffic Resource Indication IE, a sidelink TX/RX resource pool IE and an ExceptionalPool IE, and the second base station is to

• calculate a first base station resource allocation by combining the Data Traffic Resource Indication IE, the sidelink TX/RX resource pool IE and the ExceptionalPool IE with the Protected E-UTRA Resource Indication IE, and

• reply, for example by sending the E-UTRA - NR CELL RESOURCE COORDINATION RESPONSE message.

In accordance with embodiments (see for example claim 10), the second base station is to initiate the resource coordination procedure by sending a message, like the E-UTRA - NR CELL RESOURCE COORDINATION REQUEST message, to the first base station over the interface, the first base station is to reply, using for example the E-UTRA - NR CELL RESOURCE COORDINATION RESPONSE message, the reply including a Data Traffic Resource Indication IE, a sidelink TX/RX resource pool IE and an ExceptionalPool IE, and the second base station is to calculate a first base station resource allocation by combining the Data Traffic Resource Indication IE, the sidelink TX/RX resource pool IE and the ExceptionalPool IE with the Protected E-UTRA Resource Indication IE.

In accordance with embodiments (see for example claim 11), in case of conflict between the Data Traffic Resource Indication IE and the Protected E-UTRA Resource Indication IE, the sidelink TX/RX resource pool IE and the Exceptional pool IE, the first and second base station give priority to the Protected E-UTRA Resource Indication IE and then to the Exceptionalpool IE.

The present invention provides (see for example claim 12), a wireless communication system, comprising: a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, two or more of the plurality of UEs forming a group of UEs and using resources from the set of sidelink resources for a unicast or groupcast communication within the group of UEs, wherein in case one of the UEs of the group starts or completes a handover process from a source cell/base station to a target cell/base station, while one or more other UEs of the group are still served by the source cell/base station

the one UE informs the one or more other UEs about newly allocated resources in the target cell/base station, wherein the newly allocated resources may be resources of one or more exceptional or non-exceptional transmission resource pools to be used during the ongoing handover, and

responsive to the information about the newly allocated resources, the one or more other UEs start at least monitoring the newly allocated resources,

In accordance with embodiments (see for example claim 13), the one or more other UEs perform transmission on the newly allocated resources, wherein the transmission may be performed using an exceptional pool for the transition phase during the handover, or using one or more RX/TX resource pools of the target cell.

In accordance with embodiments (see for example claim 14), a message sent from the one UE to the one or more other member UEs includes a configuration of the one or more exceptional or non-exceptional transmission resource pools, or used or granted resources within one or more exceptional or non-exceptional transmission resource pools.

The present invention provides (see for example claim 15) a wireless communication system, comprising: a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the wireless communication system is to provide an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein the wireless communication system is to separate the exceptional resource set into a Rx exceptional resource set for reception and one or more additional exceptional resource sets, each of the one or more additional exceptional resource sets including one or more of

• a Tx exceptional resource set for broadcast,

• a Tx exceptional resource set for groupcast, and

• a Tx exceptional resource set for unicast.

In accordance with embodiments (see for example claim 16), the wireless communication system is to separate the exceptional resource set into a Tx exceptional resource set for broadcast,

a Tx exceptional resource set for groupcast and unicast, and

a Rx exceptional resource set for reception for all cast-types, or a Tx exceptional resource set for broadcast and groupcast,

a Tx exceptional resource set for unicast, and

a Rx exceptional resource set for reception for all cast-types, or a Tx exceptional resource set for broadcast and unicast,

a Tx exceptional resource set for groupcast, and

a Rx exceptional resource set for reception for all cast-types, or a Tx exceptional resource set for broadcast, a Tx exceptional resource set for groupcast,

a Tx exceptional resource set for unicast, and

a Rx exceptional pool for reception for all cast-types.

The present invention provides (see for example claim 17) a wireless communication system, comprising: a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the wireless communication system is to provide an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein the wireless communication system is to define in the exceptional resource set a plurality of exceptional resource subsets, each of the exceptional resource subsets being associated with a certain quality of service, QoS, class.

In accordance with embodiments (see for example claim 18), the wireless communication system is to separate the exceptional resource set into a Rx exceptional resource set for reception and one or more additional exceptional resource sets, each of the one or more additional exceptional resource sets one or more of

• a Tx exceptional resource set for broadcast,

• a Tx exceptional resource set for groupcast, and

• a Tx exceptional resource set for unicast.

The present invention provides (see for example claim 19) a wireless communication system, comprising: a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the wireless communication system is to provide different or separate exceptional resource sets for respective different causes or scenarios using or requiring an exceptional resource set. In accordance with embodiments (see for example claim 20), the wireless communication system is to provide

• for a first cause or scenario a first exceptional resource set, and

• for a second cause or scenario a second exceptional common resource set, the first and second exceptional common resource sets being different.

In accordance with embodiments (see for example claim 21 ), the first cause or scenario comprises a handover scenario, and the second cause or scenario comprises a nonhandover scenario.

In accordance with embodiments (see for example claim 22), the first and second exceptional resource sets are selected from one exceptional resource pool or from different exceptional resource pools, wherein the first and second exceptional common resource sets may include common or non-common exceptional pools

In accordance with embodiments (see for example claim 23), the one or more predefined non-handover cases include one or more of:

• an idle-to-connected situation of one or more of the UEs, and

• an RRC Reconfiguration of one or more of the UEs.

The present invention provides (see for example claim 24) a wireless communication system, comprising: a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the wireless communication system is to provide a predefined or secondary resource set to be used for SL communication in case a UE is out-of-coverage, OoC, and a sidelink communication by the UE is interrupted or disrupted.

In accordance with embodiments (see for example claim 25), the predefined or secondary resource set is used

• for a RRC reestablishment procedure or a discovery procedure to revive or reestablish a SL connection, or

• until resources in a predefined out-of-coverage resource set, e.g., a predefined out- of-coverage resource pool of the system, are available. In accordance with embodiments (see for example claim 26), the set of sidelink resources and/or the subset set of sidelink resources comprises a plurality of contiguous or noncontiguous resources across a frequency domain and adjacent or non-adjacent across a time domain.

In accordance with embodiments (see for example claim 27), the set of sidelink resources defines one or more of a resource pool (RP), a mini-resource pool (mRP), a band width part, BWP, in a resource pool, a resource pool in a BWP.

In accordance with embodiments (see for example claim 28), the plurality of UEs comprise one or more of a mobile terminal, or stationary terminal, or cellular loT-UE, or vehicular UE, or a coordinating UE within a groupcast communication, or an loT or narrowband loT, NB- loT, device, or a ground based vehicle, or an aerial vehicle, or a drone, or a moving base station, or a road side unit (RSU), or a building, or machines, e.g., in factories for industrial communication, or any other item or device provided with network connectivity enabling the item/device to communicate using the wireless communication network, e.g., a sensor or actuator.

In accordance with embodiments (see for example claim 29), the base station comprises one or more of a macro cell base station, or a small cell base station, or a central unit of a base station, or a distributed unit of a base station, or a road side unit, or a UE, or a group leader (GL), or a relay or a remote radio head, or an AMF, or an SMF, or a core network entity, or mobile edge computing entity, or a network slice as in the NR or 5G core context, or any transmission/reception point, TRP, enabling an item or a device to communicate using the wireless communication network, the item or device being provided with network connectivity to communicate using the wireless communication network.

BASE STATION

The present invention provides (see for example claim 30) a base station for the inventive wireless communication system.

The present invention provides (see for example claim 31) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, wherein the base station comprises a common set of sidelink resources, the common set of sidelink resources being

• associated with or shared among two or more of a plurality of cells/base stations of the wireless communication system, or

• associated with a particular geographical area.

The present invention provides (see for example claim 32) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, two or more of the plurality of UEs forming a group of UEs and using resources from the set of sidelink resources for a unicast or groupcast communication within the group of UEs, wherein in case one of the UEs of the group starts or completes a handover process from a source cell/base station to a target cell/base station, while one or more other UEs of the group are still served by the source cell/base station

the one UE informs the one or more other UEs about newly allocated resources in the target cell/base station, wherein the newly allocated resources may be resources of one or more exceptional or non-exceptional transmission resource pools to be used during the ongoing handover, and

responsive to the information about the newly allocated resources, the one or more other UEs start at least monitoring the newly allocated resources, wherein the base station is the target base station or the source base station.

The present invention provides (see for example claim 33) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the base station is to use an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein the exceptional resource set is separated into a Rx exceptional resource set for reception and one or more additional exceptional resource sets, each of the one or more additional exceptional resource sets including one or more of

• a Tx exceptional resource set for broadcast,

• a Tx exceptional resource set for groupcast, and

• a Tx exceptional resource set for unicast.

The present invention provides (see for example claim 34) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the base station is to provide an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein the in the exceptional resource set a plurality of exceptional resource subsets are defined, each of the exceptional resource subsets being associated with a certain quality of service, QoS, class.

The present invention provides (see for example claim 35) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the base station is to provide different or separate exceptional resource sets for respective different causes or scenarios using or requiring an exceptional resource set.

The present invention provides (see for example claim 36) a base station for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the base station is to provide a predefined or secondary resource set to be used for SL communication in case a UE is out-of-coverage, OoC, and a sidelink communication by the UE is interrupted or disrupted. USER DEVICE

The present invention provides (see for example claim 37) a user device, UE, for the inventive wireless communication system.

The present invention provides (see for example claim 38) a user device, UE, for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, wherein the UE is to use a common set of sidelink resources, the common set of sidelink resources being

• associated with or shared among two or more of a plurality of cells/base stations of the wireless communication system, or

• associated with a particular geographical area.

The present invention provides (see for example claim 39) a user device, UE, for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, two or more of the plurality of UEs forming a group of UEs and using resources from the set of sidelink resources for a unicast or groupcast communication within the group of UEs, wherein in case the UE is in a group and starts or completes a handover process from a source cell/base station to a target cell/base station, while one or more other UEs of the group are still served by the source cell/base station

the one UE informs the one or more other UEs about newly allocated resources in the target cell/base station, wherein the newly allocated resources may be resources of one or more exceptional or non-exceptional transmission resource pools to be used during the ongoing handover, and

responsive to the information about the newly allocated resources, the one or more other UEs start at least monitoring the newly allocated resources,

The present invention provides (see for example claim 40) a user device, UE, for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the UE is to use an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein the exceptional resource set is separated into a Rx exceptional resource set for reception and one or more additional exceptional resource sets, each of the one or more additional exceptional resource sets including one or more of

• a Tx exceptional resource set for broadcast,

• a Tx exceptional resource set for groupcast, and

• a Tx exceptional resource set for unicast.

The present invention provides (see for example claim 41 ) a user device, UE, for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the UE is to use an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and wherein in the exceptional resource set a plurality of exceptional resource subsets are defined, each of the exceptional resource subsets being associated with a certain quality of service, QoS, class.

The present invention provides (see for example claim 42) a user device, UE, for a wireless communication system, the wireless communication system includes a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the UE is to use different or separate exceptional resource sets for respective different causes or scenarios using or requiring an exceptional resource set. The present invention provides (see for example claim 43) a user device, UE, for a wireless communication system, the wireless communication system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, wherein the UE is to use a predefined or secondary resource set to be used for SL communication in case a UE is out-of-coverage, OoC, and a sidelink communication by the UE is interrupted or disrupted.

METHOD

The present invention provides (see for example claim 44) a method for operating the inventive wireless communication system.

The present invention provides (see for example claim 45) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, the method comprising: providing a common set of sidelink resources, the common set of sidelink resources being

• associated with or shared among two or more of a plurality of cells/base stations of the wireless communication system, or

• associated with a particular geographical area.

The present invention provides (see for example claim 46) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, for a sidelink or direct communication using resources from a set of sidelink resources of the wireless communication system, two or more of the plurality of UEs forming a group of UEs and using resources from the set of sidelink resources for a unicast or groupcast communication within the group of UEs, the method comprising: in case one of the UEs of the group starts or completes a handover process from a source cell/base station to a target cell/base station, while one or more other UEs of the group are still served by the source cell/base station

informing, by the one UE, the one or more other UEs about newly allocated resources in the target cell/base station, wherein the newly allocated resources may be resources of one or more exceptional or non-exceptional transmission resource pools to be used during the ongoing handover, and

responsive to the information about the newly allocated resources, starting, by one or more other UEs, at least monitoring the newly allocated resources,

The present invention provides (see for example claim 47) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, the method comprising: providing an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and separating the exceptional resource set into a Rx exceptional resource set for reception and one or more additional exceptional resource sets, each of the one or more additional exceptional resource sets including one or more of

• a Tx exceptional resource set for broadcast,

• a Tx exceptional resource set for groupcast, and

• a Tx exceptional resource set for unicast.

The present invention provides (see for example claim 48) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, the method comprising: providing an exceptional resource set for a transmission and/or reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, and defining in the exceptional resource set a plurality of exceptional resource subsets, each of the exceptional resource subsets being associated with a certain quality of service, QoS, class.

The present invention provides (see for example claim 49) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, the method comprising: providing different or separate exceptional resource sets for respective different causes or scenarios using or requiring an exceptional resource set.

The present invention provides (see for example claim 50) a method for operating a wireless communication system, the operating system including a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, the method comprising: providing a predefined or secondary resource set to be used for SL communication in case a UE is out-of-coverage, OoC, and a sidelink communication by the UE is interrupted or disrupted.

COMPUTER PROGRAM PRODUCT

The present invention provides a computer program product comprising instructions which, when the program is executed by a computer, causes the computer to carry out one or more methods in accordance with the present invention.

Thus, the present invention provides improvements for the communication on the sidelink among respective UEs of a wireless communication system. The aspects of the inventive approach apply for any kind of direct communication or use of sidelink communication, both in NR and LTE, including, but not being limited to:

a V2X communication, like a vehicle-to-vehicle communication, or a vehicle-to- pedestrian communication or a vehicle-to-infrastructure communication using, for example, a UE type RSU, roadside unit,

a communication among aerials, like a direct communication between any kind of unmanned aerial vehicles, UAVs,

a communication among industrial loT devices, like a sidelink communication between machines in factories,

a communication among of home loT devices using NR sidelinks,

a communication form UE-to-network or network-to-UE,

a UE-to-UE relay for a sidelink communication in NR. In case of aerials or industrial loT devices the resources granted to the UE may either be from the eNB/gNB or may be completed pre-configured. When a UE, like a UAV, experiences a RLF situation or a handover situation, an exceptional pool may be defined for these UE types as well. The exceptional pool may be a separately configured pool for the respective type of UE, for example by the 5G network core or the LTE network core.

It is noted that the present invention is not limited to the above listed kinds of direct communication, rather any kind of other direct communication may employ the inventive aspects described herein. The aspects of the present invention described herein are advantageous, for example because service continuity as well as reliability during exceptional cases, like a radio link failure, a handover or any other disruptions in the granted resources may be avoided, especially when considering advanced use cases or NR like platooning which require that exceptional resource configuration is extended to multiple cells or geographical area.

First Aspect

In accordance with embodiments of a first aspect of the present invention, common pools or common resources for the sidelink or direct communication over multiple cells or a predefined geographical area may be provided, thereby avoiding, for example, the above- mentioned problems in case UEs of a group are within different cells as then all UEs use the common resource pool for the sidelink communication so that interferences and the like are avoided or reduced. For example, a wireless system as described above with reference to Fig. 1 , Fig. 2 or Fig. 3 may provide a common set of sidelink resources, and the common set of sidelink resources may be associated with or shared among two or more of a plurality of cells or base stations of the wireless communication system or it may be associated with a particular geographical area. In accordance with embodiments, the common set of sidelink resources may include a common TX/RX pool for the transmission/reception over the sidelink as well as a common TX/RX exceptional resource pool for a transmission/reception over the sidelink in case one or more certain situations are experienced within the wireless communication system, like an idle-to-idle situation, an RRC configuration or a handover situation.

When considering, for example, the provision of a common exceptional tool, the above- mentioned drawbacks in conventional approaches and the associated problems may be addressed by defining such a common exceptional pool that is associated with multiple cells/base stations or that may be valid in a specific geographical area. Fig. 7 illustrates schematically an embodiment of the inventive approach of providing a common resource pool for a sidelink communication among UEs. Fig. 7 illustrates the concept with respect to a common exceptional pool, however, the principal is equally applicable for a common TX pool or a common RX pool or a common TX/RX pool for the sidelink communication. Fig. 7 illustrates three cells or coverage areas of base stations gNB1 , gNB2 and gNB3 as well as a group 400 of UEs UE1-UE7. A common exceptional pool 402 is illustrated which includes a plurality of time/frequency resources to be used for a sidelink communication among the UEs of the group 400 as long as they are within the respective cells gNB1-gNB3. The common exceptional pool may be configured with respect to the respective cells gNB1- gNB3 or with respect to a particular geographical area, like the area covered by the cells gNB1 - gNB3. The exceptional pool may be defined by a system information block, for example by the v2x-CommPoolExceptionalCommon-r* parameter indicated below in the example for an enhanced SysteminformationBlockTypeX IE (information element). In case the configuration of the common exceptional pool is not done via the SIB, the respective radio access network, RAN, for example the different base stations gNB1 - gNB3 may be coordinated via the backhaul, like the Xn interface, connecting the respective base stations so that these base stations may configure the common exceptional pool 402 as depicted in Fig. 7.

The above-described first aspect of the present invention may require modifications in the Layer 2 signaling so as to configure the common exceptional pool, and the subsequently described information elements or fields thereof illustrate the needed changes.

As mentioned above, the inventive approach is not limited to an exceptional pool, rather, a common pool for the regular transmission/reception over the sidelink may be established among a plurality of UEs or for a specific geographical area as well using the principles described herein.

In the following examples for modifications in the Layer 2 signaling are described for implementing the first aspect of the present invention, namely the provision of common sidelink resource pools. For example, a new or modified system information block, SIB, may be defined for a NR V2X communication. Respective information elements, lEs, may be modified by adding an indication of the area, for example by using the parameter areaScope that is defined currently for the NR Uu with respect to a validity area. The information element IE to be modified in the SIB for the V2X communication may be the SysteminformationBlockTypeX IE. This IE is described in reference [1] and may be modified so as to contain the V2X sidelink communication configuration using the respective common resource pools as shown in the example below. In the examples described herein, elements being underlined and printed in bold may be provided, modified or changed according to the inventive approach described herein.

-

In addition to the system information block, also the SL-v2x-UE-configList may be modified. The !E SL-v2x-UE-configList may indicate an inter-frequency resource configuration per carrier or per cell or by validity area, and the validity area may be denoted in the SIB by the parameter areaScope as mentioned in the SL-V2X-UE- ConfigL indicated below as validity area. Adding the validity area allows to use the same pools, like the same TX/RX pools or the same exceptional pools throughout a validity area thereby improving service continuity for a sidelink communication, like a vehicular communication in a mobility scenario and avoiding or reducing interferences. Below, an example of an SL-v2x-UE-ConfigL IE, as it is known from reference [1] is given, which is enhanced in accordance with the inventive approach.

The above described embodiments may be useful for certain applications or use cases, like platoon use cases and other dynamic groups. The UEs of the platoon or the dynamic group may exchange information with regard to the type of resource pools they may support, either via AS link management or via a higher layer or an application layer which may fall under the category of UE-capability information.

In accordance with further embodiments of the first aspect of the present invention, a common exceptional pool may be provided for an NR handover as well as for an inter- RAT handover. Similar to the X2 interface in accordance with the LTE standard, the Xn set up procedure of NR is to exchange application level configuration data that may be needed for two NR base stations, gNBs, or an NR base station and an LTE base station so as to allow a correct interoperation. The procedure may erase an existing application level configuration data in the two base stations or nodes and replace the existing application level configuration by a configuration received. For example, a source base station, which may be an eNB or a gNB, may initiate the procedure by sending the X2 SETUP REQUEST message to a candidate eNB or gNB. The candidate eNB/gNB may reply with the X2 SETUP RESPONSE MESSAGE. The initiating eNB/gNB transfers the list of the ConfiguredCommonExceptionPool to the candidate eNB/gNB which may be acknowledged by the candidate eNB/gNB.

Below an example of an Xn interface set up for a CommonExceptionPool in NR inter- cell/inter-RAT handover, as it is described in reference [7], is given which is enhanced in accordance with the principles described herein. The highlighted parts illustrate additional or modified fields when compared to the known setup.

In accordance with further embodiments of the first aspect, TX/RX/exceptional pools may be provided for the sidelink communication in a spectrum shared by E-UTRA and NR or, more generally, a spectrum that is shared by a first radio access technology, like NR, and by a second, different radio access technology, like E-UTRA, may employ a common resource pool for the sidelink communication, namely a common TX/RX exceptional pool. For example, when an eNB (first RAT) and a gNB (second RAT) share the resources or spectrum and when the coverage of the respective base stations is fully or partially overlapping, a resource coordination procedure may be employed. For example, the backhaul connection, like the Xn interface, among the base stations may be employed so as to enable the two base stations or entities to coordinate an allocation of the resources to be used for the TX/RX/exceptional pool to be used in common, thereby avoiding interference situations. During the procedure, the eNB and the gNB may exchange their intended resources for the data traffic and try to converge to a set of shared resources. This procedure may be used for the purpose of E-UTRA-NR spectrum sharing. This approach is advantageous as using different parts of a shared spectrum or of shared resources without a coordination for the sidelink TX/RX resource pool or for the exceptional pool for the eNB and for the gNB may lead to a loss in efficiency and, in addition, the probability of interferences between users may increase. Allocating the resources for the sidelink communication allows for a service continuity for users, for example V2X users, while they are moving within the cell or in case of a radio link failure- The eNB and the gNB may exchange signal information through the backhaul connection, like the Xn interface, so as to configure a part of the shared spectrum as the TX/RX resource pool or as the exceptional pool.

In accordance with the embodiments, the eNB may initiate the E-UTRA-NR cell resource coordination. More specifically, the eNB may initiate the procedure by sending the E-UTRA- NR CELL RESOURCE COORDINATION REQUEST message to a gNB over the Xn interface. The gNB may extract the Data Traffic Resource Indication IE, the Sidelink TX/RX Resource Pool IE and the Exception Pool IE. The gNB may reply by sending the E-UTRA- NR CELL RESOURCE COORDINATION RESPONSE message. The gNB, based on the information extracted from the message received from the eNB, may calculate the full eNB resource allocation by combining the Data Traffic Resource Indication IE, the Sidelink TX/RX Resource Pool IE and the Exception Pool IE with the Protected E-UTRA Resource Indication IE. Based on the calculation, the shared spectrum to be used for the respective sidelink pools may be determined.

In accordance with other embodiments, the gNB may initiate the E-UTRA-NR cell resource coordination. A gNB may initiate the procedure by sending the E-UTRA-NR CELL RESOURCE COORDINATION REQUEST message to an eNB. The eNB may reply with the E-UTRA-NR CELL RESOURCE COORDINATION RESPONSE message including the above-mentioned lEs and the gNB may calculate the full eNB resource allocation by combining the Data Traffic Resource Indication IE, the Sidelink TX/RX Resource Pool IE and the Exception Pool IE with the Protected E-UTRA Resource Indication IE. Based on the calculation, the shared spectrum to be used for the respective sidelink pools may be determined.

In case there is a conflict between the most recently received Data Traffic Resource Indication IE and the most recently received Protected E-UTRA Resource Indication IE the Sidelink TX/RX Resource Pool IE and the Exception Pool IE priority may be given to the Protected E-UTRA Resource Indication IE and then to the Exception Pool IE.

Below an example of a CELL ResourceCoordinationRequest and Response IE for an exceptional pool in E-UTRA-NR is illustrated as it is described in reference [7], wherein the enhancement in accordance with the inventive approach is highlighted.

Second Aspect

In accordance with embodiments of a second aspect of the present invention, an exceptional pool may be used for a unicast communication or for a groupcast communication during a handover situation. More specifically, in case of a handover for example for vehicles performing a unicast communication or a groupcast communication (see Fig. 5 above), the following scenario may apply. At a given time, one or multiple of the member UEs of a group that are involved in a unicast or groupcast communication may have started or may have already successfully finalized a handover process, while other member UEs are not yet involved. For example, the unicast or groupcast member(s) initially involved in the handover process may be a heading UE or vehicle of a platoon. Such a UE may be referred to as a heading UE or a leader UE. All other UEs involved in the same unicast or groupcast communication, for example vehicles following the heading UE in a platoon, may be referred to as member UEs.

As a result of an ongoing handover process, the heading UE may monitor or transmit on different resource pools, for example on an exceptional TX/RX resource pool of the target cell when compared to the other member UEs which still monitor or transmit on the resources of the resource pool of the source cell. To ensure continuity, i.e., continuous communication for the unicast or groupcast communications during a handover, embodiments of the second aspect of the present invention cause a heading UE, as soon as it is involved in the handover process, to receive information/configuration about the exceptional and/or non-exceptional transmission resource pools to be used during the ongoing handover process. This information may be included in the handover command received by the leading UE from the target cell. The heading UE may inform all other member UEs about the newly allocated resources. The message sent by the heading UE to the other member UEs may include one or more of the following:

the configuration of the one or more exceptional or non-exceptional transmission resource pools,

the used or granted resources within the exceptional and/or non-exceptional transmission resource pools.

For example, when considering a platooning use case using a groupcast communication, the heading vehicle of the platoon may perform the handover to the target cell first. Because the driving direction within the platoon is the same, all following vehicles of the platoon may have to perform the handover to the target cell as well, usually with some delay.

Upon receiving the message from the heading UE, all other member UEs may start at least monitoring the new resources of the heading UE. Also, transmissions on the new resources may be performed by the member UEs if this is enabled or allowed. Using the new heading UE resources by the other UEs may be based on one or more timers or based on measurements so as to consider the above-mentioned delays with which the other member UEs enter into the target cell.

In accordance with another embodiment, instead of using the exceptional pool for the short transition phase during the handover process, all other member UEs may use directly the RX/TX resource pools, e.g., the common RX/TX resource pools according to aspect 1 , of the target cell. In such an embodiment, the heading UE may include in the message sent to the member UEs the configuration of the resource pools for monitoring or transmission and, optionally, the used/granted resources within the common resource pools for monitoring and transmission. Applying this embodiment allows all non-heading UEs in the uni-/groupcast communication to avoid the use of the exceptional pool during the handover process.

Third Aspect

In accordance with embodiments of a third aspect of the present invention, TX/RX specific exceptional pools including cast types may be used. As mentioned above, up to Release 15 only broadcast is supported on the sidelink for a V2X communication. With Release 16, also unicast or groupcast communication is introduced so that now beside the transmission of data, also the reception of data is enabled. In accordance with embodiments of the third aspect of the present invention, a required reliability is ensured and a concurrent transmission and reception of data is enabled by providing separate exceptional pools for the transmission of different cast types.

Fig. 8 illustrates embodiments for implementing an exceptional pool. Fig. 8(a) illustrates an exceptional pool 402, for example a pool as described above with reference to Fig. 4. In the embodiment of Fig. 8(a), the exceptional pool includes an RX exceptional pool section 402a to be used for receiving data independent of the cast type, i.e., the RX exceptional pool 402a is common for all cast types. Within the exceptional pool 402, a separate TX exceptional pool 402b for broadcast and a separate TX exceptional pool 402c for groupcast and unicast is provided. However, the embodiments of the third aspect are not limited to such a structure of the exceptional pool, rather other separations may be adopted as is illustrated in Fig. 8(b) and in Fig. 8(c). In Fig. 8(b), in addition to the RX exceptional pool 402a a separate TX exceptional pool 402b for broadcast and unicast is provided as well as a separate TX exceptional pool 402e for the unicast. In Fig. 8(c), in addition to the RX exceptional pool for all cast types 402a for each cast type a separate TX exceptional pool is provided, namely a TX exceptional pool 402f for the broadcast, a separate TX exceptional pool 402g for the groupcast and a TX exceptional pool 402h for the unicast.

Applying the principles in accordance with the third aspect of the present invention may lead to resource fragmentation. In accoerdance with embodiments a resource fragmentation is avoided in that when, the UE is configured via the IE SL-CommResourcePool and SL- CommResourcePoolV2X, an indication is be added to distinguish between broadcast, groupcast or unicast. A field such as

,

*,

may be introduced and included within the resource pool defined for V2X. In this way the spectrum does not need to undergo a hard split and the exceptional pool is accordingly configured.

Fourth Aspect

In accordance with embodiments of a fourth aspect of the present invention, QoS-related exceptional pools are provided. For example, different scenarios, like different V2X scenarios, may require different QoS or Quality-of-Service parameter sets so as to guarantee certain service requirements, as is explained in reference [3] In case of highly congested scenarios, embodiments of the fourth aspect may be applied. For example, downtown in an urban city a priority may be given to cast types or to respective services or messages. When using exceptional pools, there are no configured grants and only presensing and random access is possible. In accordance with embodiments, a priority may be given to a current transmission or the current transmission may be delayed or repeated based on the CBR thresholds available. The packets to be transmitted may have different QoS classes that may be mapped to different exceptional pools, for example to an exceptional pool. This way, a packet with a higher QoS class may be prioritized over other packets. Fig. 9 illustrates an example of a prioritization in an exceptional pool 402, for example an exceptional pool as described with reference to Fig. 4. The common exceptional pool 402 may be further segregated, for example per cast type as described above with reference to the third aspect of the present invention. The prioritization holds irrespective of the design of the exceptional pool, and the priority 1 indicates in the depicted example the highest priority.

Increasing the priority increases for example the probability of access and/or the channel access duration. The QoS class may be indicated by any kind of V2X QoS indicators, for example PPPP/PPPR for LTE V2X or PQI, 5QI, VQI or any subcomponent for NR V2X.

When extending the concept of exceptional pools to the cast types, a range model may be adapted, namely a minimum communication range that may be defined by a higher layer, may be used for prioritization. For example, a TX-RX distance may be additionally associated as a selection parameter for accessing the exceptional pool. Additionally, a QoS even in normal scenarios may be used where the packet duplication may happen in the exceptional pool for use cases that require a high reliability.

Fifth Aspect

In accordance with embodiments of a fifth aspect of the present invention, a resource separation within an exceptional or non-exceptional pool for a sidelink communication may be applied dependent on the cause that led to the use of the pool. According to reference [1], an exceptional pool may be defined to be used for two different causes or scenarios, namely for a handover scenario and for a non-handover scenario in LTE V2X communications. Different methods to select the resources of the exceptional pool may apply. For the non-handover cases, for example RLF or RRC Reconfiguration, the exceptional pool configuration may be broadcast in the SIB21 of the serving cell. In this case, sensing on the exceptional pool is performed before accessing the exceptional pool. On the other hand, for the handover case the exceptional transmission resource pool is included in the handover command received by the UE from the target cell, and the UE may use randomly selected resources from the exceptional transmission resource pool once the handover command has been received.

The just mentioned two major exceptional causes, handover and non-handover causes, for accessing the exceptional pool typically demand also different latency and reliability requirements and, additionally, handover is expected to be more critical. In addition, during the handover process, no interruption may be allowed so as to fulfil a 0ms interruption time requested in 5G.

To address this situation, in accordance with embodiments of the fifth aspect of the present invention, separate resources are provided for at least two causes for using an exceptional pool, for example a first set of resources from the exceptional pool may be used for handover situations while other resources, which are different from the first resources, may be used for non-handover scenarios. It is noted that additional scenarios or causes may be defined so that the pool may be segregated in even more sub-sets or sub-pools. In accordance with embodiments, separate exceptional resource pools may be provided per cause or separate resources per cause may be provided within one common exceptional resource pool. The dimension or size of the separate resource pools or separate resources within the resource pool may be configurable and may be adapted by the network on a need basis.

An advantage of the separate resources per cause is that sensing may be restricted to those resources where the access based on sensing applies. In addition, even the more critical resources for handover have a better chance to be successfully used for transmission as there is no longer an interference with resources required for non-handover causes.

Sixth Aspect

In accordance with embodiments of a sixth aspect, a secondary or exceptional resource pool may be used for out-of-coverage situations. For example, when a UE is out of coverage, the lower layer on the sidelink may be configured to monitor sidelink control information and the corresponding data using the pool of resources that are preconfigured, for example by using the parameter preconfigComm in the SL-Preconfiguration as defined in reference [1] The UE may perform the monitoring based on a timing received from the SyncRefUE or based on an internal timing if no SyncRefUE is available. After receiving the preconfigComm in the SL-Preconfiguration, the UE may start a transmission by configuring the lower layer based on a received priority list in the SL-Preconfigurations.

The information element SL- V2X-Preconfiguration may include, in accordance with embodiments of the sixth aspect of the present invention, the sidelink preconfigured parameters used for the V2X sidelink communication as is depicted in the example below illustrating a SL-V2X-Preconfiguration information element as described in reference [1] modified in accordance with embodiments of the seventh of the present invention.

v2x-CommTXExceptionaiPooiList-r* indicates a list of radio resources by which a UE is allowed to transmits V2X sidelink communication in exceptional conditions.

- SL-PreconfigV2x-TxPoolList-r* indicates a list of preconfigured radio resource by which a UE is allowed to transmit V2X sidelink communication in out-ofcoverage scenario.

In case of a sidelink communication interruption or disruption during an out-of-coverage scenario, for example due to a radio link failure, a UE may initiate an RRC reestablishment procedure or a discovery procedure to revive or establish a connection. However, many communication types, like unicast, multicast, require a high reliability and have latency requirements which may not be met in such a situation. To address this issue, in accordance with embodiments of the sixth aspect of the present invention, the secondary pool may be defined so as to avoid a communication interruption in out-of- coverage scenarios.

The secondary out-of-coverage resource pool may be referred to as an exceptional pool or may be referred to by another term because the conditions to use this secondary pool may deviate from the mode-1 exceptional pool. A use case for a reliable and continuous sidelink connection is a groupcast or unicast communication, for example for platooning.

In case a sidelink is disrupted during an out-of-coverage scenario, the UE waits for the sensing results in order to use even the preconfigured resources and without the provision of an exceptional pool, the UE will randomly access the resource pool available. To avoid a collision possibility and a delay, the above-described out-of-coverage exceptional pool may be preconfigured, and a selection of grants in the out-of-coverage scenario using the out-of-coverage exceptional pool may be based on a preconfigured resource or grant or may be random.

GENERAL

Embodiments of the present invention have been described in detail above, and the respective embodiments and aspects may be implemented individually or two or more of the embodiments and aspects may be implemented in combination.

Embodiments of the present invention have been described in detail above with reference to a sidelink communication using the PC5 interface. However, the present invention is not limited to the use of the PC5 interface. Any other interface allowing for a direct communication among one or more UEs may be employed.

In some of the embodiments described above, reference has been made to respective vehicles being either in a mode in which SL resource allocation configuration or assistance is provided by a base station, e.g., the connected mode, also referred to as NR Mode 1 or LTE Mode 3 configuration, or vehicles being in a mode in which when no SL resource allocation configuration or assistance is provided by a base station, e.g., the idle mode, also referred to as NR Mode 2 or LTE Mode 4 configuration. However, the present invention is not limited to V2V communications or V2X communications, rather it is also applicable to any device-to-device communications, for example non-vehicular mobile users or stationary users that perform a sidelink communication, e.g., over the PC5 interface. Also, in such scenarios, e.g., due to moving obstacles, the connection to a bases station may be temporarily interrupted so the UE may be considered also out-of-coverages. The inventive aspects described above may be employed in such scenarios as well. In accordance with embodiments, the wireless communication system may include a terrestrial network, or a non-terrestrial network, or networks or segments of networks using as a receiver an airborne vehicle or a spaceborne vehicle, or a combination thereof.

In accordance with embodiments, a receiver, like a UE or a base station, may comprise one or more of a mobile or stationary terminal, an loT device, a ground-based vehicle, an aerial vehicle, a drone, a building, or any other item or device provided with network connectivity enabling the item/device to communicate using the wireless communication system, like a sensor or actuator. In accordance with embodiments, a transmitter, like a base station or a UE, may comprise one or more of a macro cell base station, or a small cell base station, or a spaceborne vehicle, like a satellite or a space, or an airborne vehicle, like a unmanned aircraft system (UAS), e.g., a tethered UAS, a lighter than air UAS (LTA), a heavier than air UAS (HTA) and a high altitude UAS platforms (HAPs), or any transmission/reception point (TRP) enabling an item or a device provided with network connectivity to communicate using the wireless communication system.

Although some aspects of the described concept have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or a device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

Various elements and features of the present invention may be implemented in hardware using analog and/or digital circuits, in software, through the execution of instructions by one or more general purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of the present invention may be implemented in the environment of a computer system or another processing system. Fig. 10 illustrates an example of a computer system 500. The units or modules as well as the steps of the methods performed by these units may execute on one or more computer systems 500. The computer system 500 includes one or more processors 502, like a special purpose or a general-purpose digital signal processor. The processor 502 is connected to a communication infrastructure 504, like a bus or a network. The computer system 500 includes a main memory 506, e.g., a random-access memory (RAM), and a secondary memory 508, e.g., a hard disk drive and/or a removable storage drive. The secondary memory 508 may allow computer programs or other instructions to be loaded into the computer system 500. The computer system 500 may further include a communications interface 510 to allow software and data to be transferred between computer system 500 and external devices. The communication may be in the from electronic, electromagnetic, optical, or other signals capable of being handled by a communications interface. The communication may use a wire or a cable, fiber optics, a phone line, a cellular phone link, an RF link and other communications channels 512.

The terms“computer program medium” and “computer readable medium” are used to generally refer to tangible storage media such as removable storage units or a hard disk installed in a hard disk drive. These computer program products are means for providing software to the computer system 500. The computer programs, also referred to as computer control logic, are stored in main memory 506 and/or secondary memory 508. Computer programs may also be received via the communications interface 510. The computer program, when executed, enables the computer system 500 to implement the present invention. In particular, the computer program, when executed, enables processor 502 to implement the processes of the present invention, such as any of the methods described herein. Accordingly, such a computer program may represent a controller of the computer system 500. Where the disclosure is implemented using software, the software may be stored in a computer program product and loaded into computer system 500 using a removable storage drive, an interface, like communications interface 510.

The implementation in hardware or in software may be performed using a digital storage medium, for example cloud storage, a floppy disk, a DVD, a Blue-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer readable.

Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.

Generally, embodiments of the present invention may be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may for example be stored on a machine readable carrier. Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

A further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein. A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet. A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein. A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

In some embodiments, a programmable logic device (for example a field programmable gate array) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware apparatus.

The above described embodiments are merely illustrative for the principles of the present invention. It is understood that modifications and variations of the arrangements and the details described herein are apparent to others skilled in the art. It is the intent, therefore, to be limited only by the scope of the impending patent claims and not by the specific details presented by way of description and explanation of the embodiments herein. References

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