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/non-slot-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
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
In mobile communication networks, for example in a network like that described above with reference to
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
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.
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 known technology that is already known to a person of ordinary skill in the art.
Starting from known technology as described above, there may be a need for improvements in the communication over the sidelink and improvements in the handling of feedback in the sidelink.
According to an embodiment, a wireless communication system may have: one or more base stations, and 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 plurality of UEs includes at least one transmitting UE and at least one receiving UE, the transmitting UE and the receiving UE configured to use at least a subset of the sidelink resources of the wireless communication system for the sidelink communication, the receiving UE configured to send over the sidelink a sidelink feedback to the transmitting UE, the sidelink feedback indicating for a data transmission a successful or non-successful reception at the receiving UE, and the transmitting UE configured to report the sidelink feedback to a base station, wherein the base station is configured to provide to the transmitting UE, responsive to the sidelink feedback, sidelink resources for a possible retransmission of a data packet over the sidelink to the receiving UE, and wherein reporting the sidelink feedback to the base station by the transmitting UE is activated or deactivated responsive to one or more conditions.
According to another embodiment, a wireless communication system may have: one or more base stations, and 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 plurality of UEs includes at least one transmitting UE and at least one receiving UE, the transmitting UE and the receiving UE configured to use at least a subset of the sidelink resources of the wireless communication system for the sidelink communication, the receiving UE configured to send over the sidelink a sidelink feedback to the transmitting UE for a plurality of data transmissions, the sidelink feedback indicating for a data transmission a successful or non-successful reception at the receiving UE, and wherein the transmitting UE configured to bundle a plurality of sidelink feedbacks received from the receiving UE for reporting to a base station.
Another embodiment may have a base station for a wireless communication system, the wireless communication system including one or more base stations, and a plurality of user devices, UEs, configured for a sidelink communication using resources from a set of sidelink resources of the wireless communication system, and wherein the plurality of UEs includes at least one transmitting UE and at least one receiving UE, the transmitting UE and the receiving UE configured to use at least a subset of the sidelink resources of the wireless communication system for the sidelink communication, the receiving UE configured to send over the sidelink a sidelink feedback to the transmitting UE, the sidelink feedback indicating for a data transmissions a successful or non-successful reception at the receiving UE, wherein the base station is to receive from the transmitting UE the sidelink feedback to a base station, wherein the base station is to provide to the transmitting UE, responsive to the sidelink feedback, sidelink resources for a possible retransmission of a data packet over the sidelink to the receiving UE, and wherein reporting the sidelink feedback to the base station by the transmitting UE is activated or deactivated responsive to one or more conditions.
Another embodiment may have a user device, UE, for a wireless communication system, the wireless communication system including one or more base stations, and 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 transmit to at least one receiving UE using at least a subset of the sidelink resources of the wireless communication system for the sidelink communication, wherein the UE is to receive from the receiving UE over the sidelink a sidelink feedback, the sidelink feedback indicating for a data transmissions a successful or non-successful reception at the receiving UE, wherein the UE is to report the sidelink feedback to a base station, wherein the UE is to receive from the base station, responsive to reporting the sidelink feedback, sidelink resources for a possible retransmission of a data packet over the sidelink to the receiving UE, and wherein reporting the sidelink feedback to the base station by the transmitting UE is activated or deactivated responsive to one or more conditions.
Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:
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.
The initial vehicle-to-everything (V2X) specification was included in LTE Release 14 of the 3GPP standard. The scheduling and assignment of resources had been modified according to the V2X requirements, while the original device-to-device (D2D) communication standard has been used as a basis of the design. Cellular V2X has been agreed to operate in two configurations from a resource allocation perspective, namely in the above-described mode 3 and mode 4 configurations. As mentioned above, in the V2X mode 3 configuration the scheduling and interference management of resources is performed by the base station for UEs so as to enable sidelink, SL, communications, like vehicle-to-vehicle communications. The control signaling is provided to the UE over the Uu interface, for example using the downlink control indicator, DCI, and is dynamically assigned by the base station. In the V2X mode 4 configuration the scheduling and interference management for SL communications is autonomously performed using distributed or decentralized algorithms among the UEs based on a preconfigured resource configuration.
Also, UEs 406 and 408, which are not members of any group, may communicate with each other or with any other UE using the sidelink interface, like the PC5 interface.
For the sidelink communication a set of resources 410 is provided from which resources may be allocated to the respective UEs for transmitting data. The set of resources 410 is also referred to as a resource pool, a mini resource pool or a sub-pool. For example, the resources 410 include a time/frequency/space resource grid, and from the resources 410 a subset of resources are selected by the base station 400 (for UEs in NR mode 1) or by the UEs (for UEs in NR mode 2) for allocation to the respective UEs for a communication over the sidelink interface. In the example of
In the Rel. 16 V2X Study Item, 3GPP agreed studying HARQ feedback mechanisms for V2X for unicast and groupcast communication. HARQ is a physical layer mechanism that enables transmitting at aggressive code rates by incorporating feedback from the receiver (destination or receiving UE). Based on the feedback retransmissions may be issued, if needed. However, many issues associated with a feedback mechanism for the sidelink are not addressed so far, e.g., providing feedback to the gNB or providing a groupcast HARQ. For example, when providing feedback to the gNB it is not specified how the feedback is reported to the gNB, since the 5G Uu interface already exists and no interface for reporting SL feedback is specified. For the groupcast HARQ no direct HARQ reporting is specified. Since a groupcast transmissions has by its own nature several receivers of which each has to report feedback for HARQ, the feedback of multiple UEs is to be multiplexed and how each individual UE need to know where and how to transmit its individual HARQ feedback.
The efficiency of SL HARQ-ACK reporting on the Uu and SL needs to be addressed, because when assuming a high number of SL unicast transmissions generating HARQ feedback, a one by one transmission method is inefficient at least in terms of spectrum.
Also, the alignment between the gNB and the UEs on the Uu for reporting content needs to be addressed. The alignment of the gNB and the reporting UE on what is transmitted needs to be ensured. A misalignment may be caused by the structure of the UCI. In contrast to the DCI, there is no blind decoding scheme with an included CRC. Hence, the gNB and the UE have to be aligned on the content as well as the size of the message.
Further, multiplexing of individual HARQ feedback transmissions for a groupcast transmission may be an issue. In groupcast multiple receivers are expected to provide HARQ-ACK feedback. While it is rather straightforward how this is realized in case of reporting of each UE to the gNB, direct reporting on the SL is not yet addressed. Additionally, reporting via the gNB introduces the problem that all UEs have to be in-coverage which may not expected for all groupcast scenarios. Hence, multiplexing the HARQ-ACK feedback of all member UEs on the SL may be used to support groupcast HARQ.
As mentioned above, for the scenario of HARQ-ACK reporting to gNB two different approaches are discussed, as shown in
In case the transmitter (source) UE reports the HARQ-ACK, as illustrated in
In case the receiver (destination or receiving) UE reports the HARQ-ACK, the receiver UE reports the HARQ-ACK to the gNB. The gNB needs to associate the reported HARQ-ACK with the corresponding transmissions by the transmitter UE. For that it either has to be aware about the transmissions received by the receiver UE or the receiver UE has to indicate the transmitter UE/transmission ID.
Also, HARQ-ACK codebook procedures may be implemented. For example, in the Uu interface, the UE is configured with slot timing values K_1·K_1 (number of slots) is a set of parameters indicating the timing at which the corresponding HARQ-ACK is transmitted. The corresponding row index of K_1 is conveyed in the DCI in the PDSCH-to-HARQ-timing field or is implicitly determined. The HARQ-ACK feedback of PDSCH transmissions pointing to the same slot for HARQ-ACK reporting is multiplexed and transmitted together in the same UCI. A semi-static HARQ-ACK codebook transmits an ACK or NACK for each PDCCH monitoring occasion associated with a K_1 pointing to the same slot regardless if there was a DCI or not. The advantage of semi-static HARQ-ACK codebook is the fixed number of bits being reported. A dynamic HARQ-ACK codebook transmits an ACK or NACK only for actually scheduled transmissions. The dynamic HARQ-ACK codebook procedure involves extra protection procedures (the total DAI and the counter DAI) to detect potentially missed DCIs such that there is not a mismatch on the number of bits being reported between gNB and UE. As is illustrated in
The present invention addresses the above issues by providing improvements in the communication over the sidelink as well as improvements in the handling of feedback in the sidelink. Embodiments of the present invention may be implemented in a wireless communication system as depicted in
In accordance with a 1st aspect, the present invention provides (see for example claim 1) a wireless communication system, comprising:
In accordance with embodiments, reporting the sidelink feedback to the base station by the transmitting UE may be deactivated or disabled responsive to a signaling triggered by the base station, the transmitting UE and/or the receiving UE.
In accordance with embodiments (see for example claim 2), the one or more conditions include one or more of:
In accordance with embodiments (see for example claim 3), the base station is configured to send a deactivation signaling to the transmitting UE to deactivate the sidelink feedback reporting, e.g. by RRC or DCI signaling, and responsive to the deactivation signaling from the base station,
In accordance with embodiments (see for example claim 4), responsive to the deactivation signaling, a selection of SL resources for the possible retransmission is performed in accordance with an out-of-coverage sidelink feedback procedure autonomously or with base station assistance but not explicitly scheduled by the base station, wherein the base station assistance may include
In accordance with a 2nd aspect, the present invention provides (see for example claim 5) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 6), the wireless communication system is configured to provide additional slot timing values for the sidelink (SL), the additional slot timing values describing the reporting window on the SL.
In accordance with embodiments (see for example claim 7), the DCIs for SL grants include a PSSCH/PDCCH-to-HARQ timing field indicating a slot timing value associated with the SL feedback reporting.
In accordance with embodiments (see for example claim 8), the slot timing value is
In accordance with embodiments (see for example claim 9), the transmitting UE is configured to bundle the sidelink feedbacks in a separate feedback procedure dedicated for the SL, e.g., a separate HARQ-ACK codebook, or to multiplex the sidelink feedbacks into a feedback procedure dedicated for the Uu, e.g., the Uu or common HARQ-ACK codebook.
In accordance with embodiments (see for example claim 10),
In accordance with embodiments (see for example claim 11), the base station is configured to send a signaling to the transmitting UE to activate or deactivate the bundling of the sidelink feedbacks, e.g. by RRC or DCI signaling.
In accordance with a 3rd aspect, the present invention provides (see for example claim 12) a wireless communication system, comprising:
one or more base stations, and
In accordance with embodiments (see for example claim 13), the wireless communication system is to configure the transmitting UE with one or more periodic uplink resources, e.g., a PUCCH resource, for transmitting an uplink control message, like a UCI, to transmit the indication to the base station.
In accordance with embodiments (see for example claim 14), the transmitting UE transmits the uplink control message via the MAC layer, e.g. using MAC Control Elements, to transmit the indication to the base station.
In accordance with embodiments (see for example claim 15), the uplink control message comprises one or more of the following:
In accordance with a 4th aspect, the present invention provides (see for example claim 16) a wireless communication system, comprising:
one or more base stations, and
In accordance with embodiments (see for example claim 17), the PHY layer uses received SL grants first for retransmissions and then for new data transmissions.
In accordance with a 5th aspect, the present invention provides (see for example claim 18) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 19), reporting the sidelink feedback to the base station by the receiving UE is deactivated or disabled when
In accordance with embodiments (see for example claim 20), reporting the sidelink feedback to the base station by the receiving UE is deactivated or disabled responsive to a signaling triggered by the base station, the transmitting UE and/or the receiving UE.
In accordance with embodiments (see for example claim 21), in case the signaling is triggered by the base station, the base station is configured to send a signaling to the receiving UE, e.g., by RRC or DCI signaling, to deactivate SL feedback reporting to the base station, and, responsive to the signaling, the receiving UE is configured to stop reporting/forwarding the SL feedback to the base station,
In accordance with embodiments (see for example claim 22), responsive to the deactivation of the SL feedback reporting signaling, the transmitting UE and the receiving UE are configured to switch to an out-of-coverage sidelink feedback procedure, e.g., a Mode 2 HARQ procedure.
In accordance with a 6th aspect, the present invention provides (see for example claim 23) a wireless communication system, comprising:
one or more base stations, and
In accordance with embodiments (see for example claim 24), in case the base station is not aware of the transmitting UE, the receiving UE is configured to generate the sidelink feedback for several data transmissions and to bundle the sidelink feedback for reporting to the base station together with one or more IDs of the corresponding transmitting UEs, wherein the maximum number of IDs and maximum number of HARQ-ACK bits provided in the report may be configured or fixed by specification.
In accordance with embodiments (see for example claim 25), the wireless communication system is to configure the receiving UE with one or more periodic uplink resources, e.g., a PUCCH resource, for transmitting an uplink control message, like a UCI, the uplink control message indicating the pairs of bundled sidelink feedback and the ID of the corresponding transmitting UE.
In accordance with embodiments (see for example claim 26), in case the base station is aware of the transmitting UE, the receiving UE is configured to generate the sidelink feedback for several data transmissions and to bundle the sidelink feedback for reporting to the base station.
In accordance with embodiments (see for example claim 27), the wireless communication system is to configure the receiving UE with one or more periodic uplink resources, e.g., a PUCCH resource, for transmitting an uplink control message, like a UCI, the uplink control message indicating the bundled sidelink feedback.
In accordance with embodiments (see for example claim 28), the receiving UE is configured to bundle the sidelink feedbacks in a separate feedback procedure dedicated for the SL, e.g., a separate HARQ-ACK codebook, or to multiplex the sidelink feedbacks into a feedback procedure dedicated for the Uu, e.g., the Uu or common HARQ-ACK codebook.
In accordance with embodiments (see for example claim 29), the base station is configured to send a signaling to the receiving UE to activate or deactivate the bundling of the sidelink feedbacks, e.g. by RRC or DCI signaling.
In accordance with a 7th aspect, the present invention provides (see for example claim 30) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 31),
In accordance with embodiments (see for example claim 32), the receiving UE is configured to indicate, using a sidelink assignment index (SAI), missed transmissions with a NACK in the corresponding order in the bundled feedback.
In accordance with embodiments (see for example claim 33), the receiving UE reports a NACK for all transmission which do not fulfill the minimum processing time requirements at the time of reporting.
In accordance with embodiments (see for example claim 34),
In accordance with embodiments (see for example claim 35), the receiving UE sets the feedback for not received feedback timing indicators to NACK.
In accordance with embodiments (see for example claim 36), the transmitting UE is configured to request from the receiving UE an immediate sidelink feedback by sending to the receiving UE, instead of a first value, the second value for the feedback timing indicator.
In accordance with embodiments (see for example claim 37), the feedback timing indicator points to a specific resource, e.g. the number of slots from current resource to the resource in which the feedback is to be provided.
In accordance with embodiments (see for example claim 38), the feedback timing indicator is the number of transmissions till reporting, e.g. a counter which starts with the largest number and decreases with each transmission by one.
In accordance with embodiments (see for example claim 39), the wireless communication system is to configure the receiving UE to bundle and report the sidelink feedback over a certain window of time slots or transmissions to the transmitting UE, wherein the window may be defined by one or more of:
In accordance with embodiments (see for example claim 40), the receiving UE is configured to transmit the sidelink feedback in its own transmission, and wherein the receiving UE may signal to the transmitting UE that its data region includes control data, the control data including the sidelink feedback.
In accordance with embodiments (see for example claim 41), reporting the sidelink feedback is triggered by the receiving UE or by the transmitting UE.
In accordance with embodiments (see for example claim 42), in case reporting the sidelink feedback is triggered by the transmitting UE,
In accordance with an 8th aspect, the present invention provides (see for example claim 43) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 44), the UE-specific sequence indicates a non-successful data transmission
In accordance with embodiments (see for example claim 45), in case the UEs form a group, the UE-specific sequences are either configured during group setup or are derived implicitly from, e.g., a member ID of the UE.
In accordance with a 9th aspect, the present invention provides (see for example claim 46) a wireless communication system, comprising:
one or more base stations, and
In accordance with embodiments (see for example claim 47), the first and second channels comprise different resources and/or use different, e.g., orthogonal, sequences to signal a successful transmission and a non-successful transmission, respectively.
In accordance with embodiments (see for example claim 48), each receiving UE is configured to transmit in the first channel if it could decode the transmission successfully, otherwise it transmits in the second channel.
In accordance with embodiments (see for example claim 49), the first channel is a SCI-confirmation channel, and wherein each receiving UE is configured to transmit in the SCI-confirmation channel independent of the decoding outcome, and, if the transmission cannot be decoded, the receiving UE transmits in the second channel additionally.
In accordance with a 10th aspect, the present invention provides (see for example claim 50) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 51), a channel is used to report the feedback, the first channel being is split into respective sub-resources, each subresource being used by a single receiving UE.
In accordance with embodiments (see for example claim 52), using the UE ID and the group size, the receiving UE derives its sub-resources for transmitting the feedback, wherein the number of sub-resources may be determined either dynamically, e.g., using on an actual group size, or by using the maximum group size, which may be configurable or fixed.
In accordance with embodiments of all preceding aspects (see for example claim 53), the transmitting UE is configured to signal to the receiving UE a sidelink assignment index (SAI), e.g., in a SCI message, so as to allow the receiving UE to detect missed transmissions, wherein for a first transmission to a certain receiving UE a SAI counter is set in an initial value and the SAI counter is increased with each transmission to said certain receiving UE.
In accordance with an 11th aspect, the present invention provides (see for example claim 54) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 55), the wireless communication system is configured to schedule the transport block (TB) over multiple resource blocks using a single sidelink control message indicating an allocation over multiple resources or using several sidelink control messages, each sidelink control message indicating its associated resources.
In accordance with embodiments (see for example claim 56), a TB is divided into Code Block Groups (CBG). Each of the CBGs being decodable on its own and generating one HARQ feedback bit.
In accordance with embodiments (see for example claim 57), a CBG is mapped to a resource block.
In accordance with embodiments (see for example claim 58), a first CBG is mapped to a first region of a resource block corresponding to data in other transmissions and a second CBG is mapped into a second region of the resource block corresponding to a feedback region used by a different UE than the UE using the data region.
In accordance with embodiments (see for example claim 59), in case several sidelink control messages are used to schedule the transport block (TB) over multiple resource blocks, a CBG transmission indicator is used to indicate which CBGs are transmitted in a current transmission, wherein the indicator may include one or more of:
In accordance with embodiments (see for example claim 60),
In accordance with embodiments (see for example claim 61),
In accordance with a 12th aspect, the present invention provides (see for example claim 62) a wireless communication system, comprising:
In accordance with embodiments (see for example claim 63), the receiving UE is configured to forward a sensing report to the transmitting UE so that the transmitting UE is aware of potentially interfered resources.
In accordance with embodiments of all preceding aspects (see for example claim 64), the sidelink communication comprises
In accordance with embodiments of all preceding aspects (see for example claim 65), a retransmission includes:
In accordance with embodiments of all preceding aspects (see for example claim 66), the one or more redundancy versions provide for an incremental redundancy at a receiver.
In accordance with embodiments of all preceding aspects (see for example claim 67), the sidelink resources include at least a first group of resources having a first numerology and a second group of resources having a second numerology, the first and second numerologies being different.
In accordance with embodiments of all preceding aspects (see for example claim 68), the set of sidelink resources and/or the subset set of sidelink resources comprises a plurality of contiguous or non-contiguous resources across a frequency domain and adjacent or non-adjacent across a time domain.
In accordance with embodiments of all preceding aspects (see for example claim 69), the set of sidelink resources defines one or more of:
In accordance with embodiments of all preceding aspects (see for example claim 70), the plurality of UEs comprise one or more of: a mobile terminal, or stationary terminal, or cellular IoT-UE, or vehicular UE, or vehicular group leader (GL) UE, or an IoT or narrowband IoT, NB-IOT, device, or a ground based vehicle, or an aerial vehicle, or a drone, or a moving base station, or road side unit, or a building, 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 of all preceding aspects (see for example claim 71), 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), 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.
In accordance with further aspects, the present invention provides a base station for the inventive wireless communication system described herein.
In accordance with further aspects, the present invention provides a user device, UE, for the inventive wireless communication system described herein.
In accordance with further aspects, the present invention provides method for operating the inventive wireless communication system described herein.
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 in the communication over the sidelink as well as improvements in the handling of feedback in the sidelink. To improve efficiency and interworking of Uu and SL transmissions the present invention proposes various procedures.
In accordance with an aspect of the inventive approach, embodiments provide a feedback bundling for HARQ-ACK reporting via the gNB. For example, one or more of the following may be implemented (as shall be described in more detail below):
In accordance with another aspect of the inventive approach, embodiments provide for a feedback bundling for HARQ-ACK reporting on the SL. For example, one or more of the following may be implemented (as shall be described in more detail below):
At least for Mode 2 and possibly also for Mode 1, the UE is expected to transmit HARQ-ACK feedback via the SL interface. However, as mentioned previously, if large amounts of data are transmitted via SL, a lot of HARQ-ACK feedback is generated. A one by one transmission degrades the spectral efficiency of SL HARQ-ACK transmissions. Hence, this aspect proposes different bundling procedures to transmit HARQ-ACK feedback on the SL interface, as shall be described in more detail below.
In accordance with a yet another aspect of the inventive approach, embodiments provide for groupcast HARQ-ACK multiplexing. For example, one or more of the following may be implemented (as shall be described in more detail below):
different NACK sequences
For groupcast transmissions, multiple UEs have to provide HARQ-ACK feedback to the source UE, but know approaches for HARQ-ACK transmission over the SL several restrictions and drawbacks. This aspect proposes solutions to cope with these restrictions and drawbacks so as to improve HARQ-ACK feedback transmission on the SL for a groupcast, as shall be described in more detail below.
In accordance with a further aspect of the inventive approach, embodiments provide for a code block group (CBG) or resource block (RB) transmission. For example, one or more of the following may be implemented (as shall be described in more detail below):
Transmitting large amounts of data may be restricted by the resource unit size in the SL. Hence, transmissions spanning RBs, like multiple time and/or frequency resource units, may be used. This aspect proposes a SL transmission spanning multiple resource units or RBs in time and/or frequency. This may also affect the interference behavior since parts of such a large transmission may be affected more severely by interference than others. That leads to unequal error probabilities for each resource unit of the transport block (TB). Thus, retransmitting the whole block is inefficient because the other parts not affected by interference will be decoded properly in most of the cases. Therefore, a finer, more granular HARQ-ACK feedback is proposed to enable a more efficient retransmission, as shall be described in more detail below.
In accordance with a yet further aspect of the inventive approach, embodiments provide a link information message (Mode 2). For example, the destination UE may make the source UE aware of its transmit windows. In out-of-coverage scenarios, i.e., Mode 2, collisions due to the half-duplex constraint may arise. This comes from the limitation that a UE may not be able to receive and transmit at the same time. Hence, if it receives a packet during transmission this inevitably results in a packet failure. This issue is addressed by the inventive approach by providing or introducing a link information message which tells another SL UE which timeslots to avoid due to periodic transmissions, e.g. SPS, reference symbol transmissions or other kind of predictable transmissions, as shall be described in more detail below.
Embodiments of the present invention will now be described in more detail.
Enhancements for SL Harq with Transmitter UE Reporting Harq-ACK to the gNB
Activation/Deactivation of HARQ-ACK reporting
Embodiments of the present invention implement an activation/deactivation of the HARQ-ACK reporting. In case the transmitter/source UE reports the HARQ-ACK feedback to the gNB, it is clear for the gNB to which UE to provide the SL grant for a possible retransmission. Also, the issue that the source UE is out-of-coverage and may not be provided with a SL grant, is not a problem since in that case the source UE does not transmit the HARQ-ACK to the gNB and may automatically switch to a Mode 2 HARQ scheme.
However, even in coverage it may be beneficial to stop the source UE from reporting HARQ-ACK to the gNB, e.g., to reduce PUCCH utilization on the SL and/or if there is not much traffic on the SL to avoid unnecessary reporting overhead on Uu.
The gNB sends a signaling to the reporting UE (the UE transmitting the HARQ-ACK feedback to gNB) to activate or deactivate HARQ-ACK reporting, e.g. by RRC or DCI. The reporting UE then stops reporting/forwarding the HARQ-ACK feedback to the gNB. In this case, the HARQ procedure may automatically switch to the Mode 2 HARQ procedure (out-of-coverage procedure).
After receiving the deactivation signaling, the transmitter UE stops forwarding/indicating SL HARQ-ACK to the gNB. The resource selection for future retransmissions may be performed as in Mode 2 autonomously or with gNB assistance but not explicitly scheduled by the gNB.
For example, RRC enabling and disabling of the SL HARQ reporting may employ the following RRC PUCCH-Config information element
For example, for a destination-specific reporting (UE reports only for explicitly indicated SL destination IDs) the following RRC PUCCH-Config information element may be employed:
In the Uu interface, the UE may bundle the HARQ-ACK feedback for DL transmissions in so-called HARQ-ACK codebooks and transmit them in the PUCCH or the PUSCH to the gNB. However, these mechanisms are designed for DL only and do not consider any SL transmissions. Therefore, embodiments of the present invention propose an approach to incorporate the SL HARQ-ACK feedback in the PUCCH or PUSCH transmissions.
In accordance with embodiments, the transmitter UE awaits the HARQ-ACK feedback for several transmissions from the receiving UE and bundles it (the feedback) for reporting to the gNB. This enables a more efficient transmission in the Uu interface. The bundling may be activated or deactivated by gNB, by e.g. DCI or RRC signaling. In the Uu interface, the UE may bundle the HARQ-ACK feedback in so-called HARQ-ACK codebooks, which may operate in dynamic or semi-static mode. The UE may bundle the SL HARQ-ACK feedback either in a separate HARQ-ACK codebook procedure dedicated for SL or multiplex the SL HARQ-ACK into the Uu HARQ-ACK codebook (common codebook).
In accordance with embodiments, separate slot timings K_1 may be used for the SL. Since the SL HARQ procedure is expected to take more time if the transmitter UE is reporting when compared to a Uu HARQ, additional slot timing values K_1 are provided to describe the reporting window on the SL. The PDSCH-to-HARQ timing field may be conveyed in DCIs for SL grants and indicates one slot timing value K_1 associated with the SL feedback reporting.
For example, the following RRC PUCCH-Config information element may be employed:
For example, a DCI format for scheduling the SL may be scrambled with the corresponding UE-specific RNTI and include one or more of:
The reference of the K_1 value indicated by the PSSCH/PDCCH-to-HARQ_feedback timing indicator may either be the PSSCH or the PDCCH scheduling the corresponding PSSCH.
In accordance with embodiments, the SL interface may be treated as an additional serving cell. Hence, the DAI also counts DCIs for scheduling the SL grants so that the UE is able to detect missed SL grants. As is illustrated in
In accordance with embodiments, the DAI for scheduling SL transmissions in the DCI may incremented independently from the DAI for Uu transmissions. The PDCCH monitoring occasions for Uu grants and for SL grants are handled independently. Thus, the UE is able to detect missed SL grants based on the SL DAI. As is illustrated in
In accordance with embodiments, the HARQ-ACK codebook may be constructed based on a semi-static or on a dynamic method, and codebook related parameters may be conveyed in DCIs for scheduling SL grants.
For example, a DCI format for scheduling SL may be scrambled with the corresponding UE-specific RNTI and include one or more of:
The packets passed from the MAC layer to the PHY do not appear anymore in the BSR, which is reported from the MAC of the UE to the gNB to ask for new resources. In case a transmission fails in the SL and a retransmission may be used, a new resource has to be allocated. In accordance with embodiments, it is proposed that in that case the PHY layer reports the failed transmission to the MAC layer such that the failed transmission may be handled as a new packet from a MAC perspective. The MAC layer sums up the size of the retransmission to the corresponding logical channel in the BSR so that when asking for the resources using the BSR, also resources for the retransmission may be provided by the base station.
In accordance with embodiments, the transmitting UE is configured with a periodic PUCCH resource for transmitting a UCI indicating the number of resources that may be used for retransmissions/transmissions. The Resource Request Report (RRR) may include one or more of the following:
In accordance with embodiments, the transmitting UE is configured to report the number of resources that may be used on the MAC layer. This may be triggered by the transmitting UE itself, the network or may be configured to be periodically. The Resource Request Report (RRR) may include one or more of the following:
In accordance with embodiments, the transmitting UE is configured, e.g. via Uu RRC, with an additional scheduling request bit which it reports in each UCI reporting HARQ-ACK to the gNB. In case that the UE needs a SL resource due to an unexpected retransmission, the UE sets this bit to one which indicates the gNB that the UE necessitates a SL resource. In response the gNB provides a SL grant for the said UE.
For example, the following element may be employed in the Uu RRC configuration:
Enhancements for SL Harq with Receiver UE Reporting Harq-ACK to the gNB
When letting the destination UE report the HARQ-ACK feedback, a current connectivity status of the source UE may not be known at the destination UE side. For example, this may be a problem if a retransmission is requested by the destination UE but the source UE is out-of-coverage. In this case, the gNB may not reach the source UE to provide resources for retransmission. Hence, in accordance with embodiments, it is proposed to disable HARQ-ACK reporting to the gNB. The signaling may be triggered either by the gNB or by the source UE or by the destination UE.
In accordance with embodiments, the gNB sends a signaling to the reporting UE (the UE transmitting the HARQ-ACK feedback to the gNB) to activate or deactivate the HARQ-ACK reporting, e.g. by RRC or DCI. The reporting UE then stops reporting/forwarding the HARQ-ACK feedback to the gNB. In this case, the HARQ procedure may automatically switch to the Mode 2 HARQ procedure (out-of-coverage procedure) with autonomous or only gNB assisted resource selection by the transmitter UE. The gNB assistance may incorporate a resource pool/mini-resource pool configuration or configured grants in a SPS-like manner.
In accordance with embodiments, the transmitter UE activates/deactivates HARQ-ACK reporting of the receiver UE depending on its own coverage situation. When being out-of-coverage, the transmitter UE may not receive any SL resource grants by the gNB, and it assigns the receiver UE to switch to the Mode 2 HARQ procedure, e.g. implicitly by providing or not providing a SL resource for HARQ-ACK reporting or by using a corresponding pool (Mode 1/Mode 2 pool, etc.).
In accordance with embodiments, the destination UE tells the source UE that it is out-of-coverage and should expect the HARQ-ACK on the SL. The receiver UE also informs the gNB.
For example, for RRC enabling and disabling of SL HARQ reporting the following RRC PUCCH-Config information element may be employed:
For example, for a source-specific reporting (UE reports only for explicitly indicated SL source IDs) the following RRC PUCCH-Config information element may be employed:
In accordance with embodiments, an exceptional pool may be preconfigured with the source and the destination UEs, and in case that one of the UEs gets out-of-coverage, it will transmit on the exceptional pool, which makes the other UE aware to use Mode 2 HARQ procedure.
In accordance with embodiments, to ensure the receiver UE detects missed transmissions, the transmitter UE conveys a SAI counter in the SCI. The counter is increased with each transmission to the same UE. In the first transmission the SAI is set to 0. The HARQ-ACK feedback for missed transmissions is set to NACK.
In accordance with embodiments, the receiver UE generates the HARQ-ACK feedback for several transmissions and bundles it for reporting to the gNB together with an identification of the transmitting UE. This enables a more efficient transmission on the Uu interface. The bundling may be activated or deactivated by gNB, by e.g. DCI or RRC signaling.
In accordance with embodiments, the UE is configured with a periodic PUCCH resource for transmitting a UCI indicating the ACKs and NACKs for transmissions. This HARQ-ACK
Report may include one or more of the following:
In accordance with embodiments, the receiver UE generates the HARQ-ACK feedback for several transmissions and bundles it for reporting to the gNB. This enables a more efficient transmission on the Uu interface. The bundling may be activated or deactivated by gNB, by e.g. DCI or RRC signaling.
Embodiments provide the following approaches to provide the HARQ-ACK feedback to the gNB.
The UE may be configured with a periodical PUCCH resource for HARQ-ACK reporting. Based on the periodicity, the number of transmissions and/or an additional configured size indicator, the UE transmits a number of bits representing HARQ-ACK feedback for all received/potentially received transmissions of a preconfigured time window.
A HARQ-ACK codebook may be constructed and transmitted separately from the Uu HARQ-ACK codebook or multiplexed into it, as described above in the section “HARQ-ACK codebooks”. Since the gNB is aware of all the transmissions it may associate the individual HARQ-ACK bits to the corresponding transmissions based on the order.
As described above, transmitting the HARQ-ACK feedback on the SL one by one may degrade the spectral efficiency. Hence, embodiments of the present invention provide bundling the feedback. The bundling in the SL interface may be applied to Mode 2 HARQ-ACK reporting but also to the reporting in SL for Mode 1 HARQ procedure, if the transmitter/source UE is providing the HARQ-ACK feedback to the gNB.
In accordance with embodiments, to ensure the receiver UE detects missed transmissions, the transmitter UE conveys a SAI counter in the SCI, as has been described above with reference to
In accordance with embodiments, the transmitter UE conveys a feedback request indicator field (HR) in the SCI. This field is set to 0 to indicate that the receiver UE should continue bundling the HARQ-ACK feedback. If this field is set to 1, a part of the associated data resource is reserved for the receiver UE to transmit its bundled feedback in this resource. The size of this resource may be fixed or indicated by a separate field in the SCI. With help of the SAI field of the received transmissions the receiver UE fills up the missed transmissions with a NACK in the corresponding order and reports the bundled feedback. This way it is ensured that the receiver UE and transmitter UE are aligned on the number of bits expected for feedback (during a minimum processing time).
In case that the minimum processing time is not met for the reporting because the last transmission was timely to close to the feedback request, the UE may report a NACK for that transmission.
In accordance with embodiments, the transmitter UE conveys a HARQ-timing indicator field (HTI) in SCI, which indicates on its own or in combination with a RRC configured K1 value, the resource where to report the HARQ-ACK feedback, which fulfils the processing timeline. This timing indication may be absolute in terms of a number of slots or relative in terms of a number of transmissions/packets. In the corresponding resource the transmitter UE reserves a part or the whole resource for the feedback transmission of the receiver UE.
For example, a HTI may be based on absolute units, e.g. slots, and for signaling the HTI the following RRC PUCCH-Config information element may be employed:
The sl-DataToSL-ACK values may point to the resource which is planned to be used for the PSFCH transmission (see
In accordance with embodiments, an early report may be desired, e.g., in case the transmitter UE does not have more packets to transmit and thus wants to receive the HARQ-ACK feedback immediately. In this case the TX UE may transmit a SCI with the HARQ-ACK timing indicator set to 0. This overwrites the previous HARQ-ACK timing indicators and the receiver UE reports all previous HARQ-ACK feedback in the associated resource.
In accordance with embodiments, the gNB configures the source and the destination UEs with a periodic PSFCH allocation, in a SPS-like manner. In this slot the source UE uses only a subset of the data region and expects the destination UE's feedback in parts of the remaining data region (see
In accordance with embodiments, the receiver UE is configured implicitly or by the gNB to report over a window of slots/transmissions to a TX UE. The window may be defined by:
Other than in the preceding embodiments, in this embodiment the destination/receiver UE transmits the HARQ-ACK feedback in its own transmission. The RX UE conveys a field in its SCI indicating the associated control data in its data region. This may be realized by a Control Factor (CF) which indicates the ratio of control and data. The RX UE may reserve a smaller or larger part of the data region for control data including the HARQ-ACK feedback and/or additional control information, e.g. measurement reports, CQI, etc.
The reporting may be triggered either by the receiver UE itself or by the transmitter UE, as discussed in the following section.
In accordance with embodiments, the transmitter UE conveys a field in its SCI to request a HARQ-ACK reporting from the receiver UE. If the receiver UE decodes this field, it bundles all the buffered feedback related to the transmitter UE and transmits it in a next transmission either multiplexed with data or not. The field in the SCI triggering the feedback transmission may also be the aforementioned HR or HTI.
In accordance with embodiments, to avoid a destructive channel sum effect each reporting UE uses a UE-specific sequence, e.g. a different cyclic shift on the same sequence, to signal a NACK on the common HARQ resource. This sequence (or parameters for the sequence generation) may either be configured during group setup or derived implicitly from, e.g., a member ID of a UE.
NACK-based reporting may involve distinguishing the all ACK case from the SCI missed case. To address this, embodiments of the present invention propose introducing an ACK or SCI-confirmation channel. This is a channel with different resources from the NACK channel or using different (e.g., orthogonal sequences) from the NACK channel.
In accordance with embodiments, each UE transmits in the ACK channel if the transmission is decoded successfully, otherwise it transmits in the NACK channel.
In accordance with embodiments, each UE transmits in the SCI-confirmation channel independent of the decoding outcome. If the transmission is not decoded, the UE transmits additionally in the NACK channel.
In accordance with embodiments, the HARQ-ACK channel is split into subresources each used by a single receiver UE, as is illustrated in
The UE ID may be assigned
To enable transmission of large data packets, embodiments of the present invention propose scheduling one transport block (TB) over multiple resource blocks (RBs), e.g. multiple slots and/or frequency resources in the SL. This may be achieved by introducing a new SCI format indicating an allocation over multiple resources or using several SCIs each indicating its associated resource, as depicted in the right and left, respectively.
In the SL there may exist uniform resource blocks (RBs) which include a control region carrying a single SCI, a data region carrying the Physical Sidelink Shared Channel (PSSCH) and optionally a feedback region carrying the Physical Sidelink Feedback Channel (PSFCH) (see
Embodiments may provide:
In accordance with embodiments, a SAI in the SCI is increased by one per CBG. This ensures that even if the UE misses the whole CBG transmission, it knows how many HARQ-ACK bits to transmit.
In accordance with embodiments, if several SCIs are used for scheduling the CBG transmission, a CBG Transmission Indicator (CBGTI) field may be used to indicate which CBGs are transmitted in the current transmission. The CBGTI may include one or more of the following:
In accordance with embodiments, if the number of CBGs is fixed per transmission, e.g. RRC configured, or indicated in the SCI, then the UE generates a HARQ-ACK subcodebook which includes X bits, where X is the number of actually transmitted CBGs or the maximum number of CBGs. Each HARQ-ACK bit corresponds to the feedback of one associated subtransmission.
In case of HARQ-ACK codebooks indicating only the number of resources, each CBG is treated as a separate resource. Hence, retransmitting two CBGs of a four CBG transmission would result in an indication of two retransmission resources that may be used.
In out-of-coverage scenarios, the half-duplex constraint poses a severe limitation. Embodiments of the present invention propose a signaling conveyed via SL, e.g. using SL RRC, or by the gNB to the potential source UEs, e.g. using RRC, to inform the them about periodic transmissions of the potential destination UE which in turn may be avoided by them when transmitting to the said destination UE.
The reporting may be provided as:
In accordance with embodiments, the destination UE forwards its sensing report to the source UE, such that the source UE is aware of potentially interfered resources.
The reporting may be provided as:
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 may be implemented in combination.
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 mode 1 or 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 mode 2 or 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, the inventive aspects described above may be employed.
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 may comprise one or more of a mobile or stationary terminal, an IoT 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 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.
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 600. The computer programs, also referred to as computer control logic, are stored in main memory 606 and/or secondary memory 608. Computer programs may also be received via the communications interface 610. The computer program, when executed, enables the computer system 600 to implement the present invention. In particular, the computer program, when executed, enables processor 602 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 600. Where the disclosure is implemented using software, the software may be stored in a computer program product and loaded into computer system 600 using a removable storage drive, an interface, like communications interface 610.
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 may be performed by any hardware apparatus.
While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations and equivalents as fall within the true spirit and scope of the present invention.
Number | Date | Country | Kind |
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19151273.0 | Jan 2019 | EP | regional |
This application is a continuation of the U.S. application Ser. No. 17/370,647 filed on Jul. 8, 2021 which is a continuation of International Application No. PCT/EP2020/050398, filed on Sep. 1, 2020, which claims the benefit of EP Patent Application No. EP 19151273.0, filed on Oct. 1, 2019. These applications are hereby incorporated by reference herein. 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 in the communication over the sidelink as well as improvements in the handling of feedback in the sidelink, like an advanced HARQ feedback.
Number | Date | Country | |
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Parent | 17370647 | Jul 2021 | US |
Child | 18597987 | US | |
Parent | PCT/EP2020/050398 | Jan 2020 | WO |
Child | 17370647 | US |