EP3707938A1

EP3707938A1 - Carrier aggregation for sidelink communications

Info

Publication number: EP3707938A1
Application number: EP17931165.9A
Authority: EP
Inventors: Vinh Van Phan; Haitao Li; Ling Yu; Jedrzej STANCZAK
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2017-11-09
Filing date: 2017-11-09
Publication date: 2020-09-16
Also published as: CN111316718A; WO2019090605A1; CN111316718B; EP3707938A4

Abstract

Various communication systems may benefit from improved carrier aggregation. For example, certain communication systems may benefit from improved sidelink carrier aggregation in vehicle-to-everything communication. A method, in certain embodiments, may include receiving at a user equipment a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The method may also include determining to transmit data using the sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the method may include transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.

Description

CARRIER AGGREGATION FOR SIDELINK COMMUNICATIONS

BACKGROUND:

Field:

Various communication systems may benefit from improved carrier aggregation. For example, certain communication systems may benefit from enhanced sidelink carrier aggregation in a vehicle-to-everything communication.
Description of the Related Art:
Recent developments in Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) technology or LTE-Advanced (LTE-A) have sought to improve vehicle-to-everything communications. Vehicle-to-everything communication is the passing information from a vehicle to any entity that may affect the vehicle. For example, vehicle-to-everything communications can involve vehicle-to-infrastructure, vehicle-to-vehicle, vehicle-to-pedestrian, vehicle-to-device, or vehicle-to-grid communications.
Vehicle-to-everything communications support carrier aggregation (CA) over sidelink (SL) for vehicle-to-everything communication, referred to hereinafter as sidelink carrier aggregation (SLCA) . SL is a vehicle-to-everything interface that allows for direct communication and direct discovery. CA is used for parallel transmission of medium access control (MAC) protocol data unit (PDU) , in which MAC PDU payload are different. CA can also be used in parallel transmission of replicated copies of the same packet. Parallel means at the same or different transmission time, but on different carriers. From the receiver’s perspective, simultaneous reception over multiple carriers is assumed. From the transmitter’s perspective, transmission occurs over a subset of the available carriers.
SUMMARY
According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to receive a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to determine to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to transmit data using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
A method, in certain embodiments, may include receiving at a user equipment a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The method may also include determining to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the method may include transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
An apparatus, in certain embodiments, may include means for receiving at a user equipment a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The apparatus may also include determining to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the apparatus may include transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
According to certain embodiments, a computer program product embodied in a non-transitory computer-readable medium and encoding instructions that, when executed in hardware, perform a process. The process may include receiving at a user equipment a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The process may also include determining to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the process may include transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include receiving at a user equipment a sidelink carrier aggregation configuration. The sidelink carrier aggregation configuration may include a timing offset. The process may also include determining to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier. In addition, the process may include transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to configure a sidelink carrier aggregation configuration comprising a timing offset. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to transmit to a user equipment the sidelink carrier aggregation configuration comprising the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier.
A method, in certain embodiments, may include configuring at a network entity a sidelink carrier aggregation configuration comprising a timing offset. The method may also include transmitting from the network entity to a user equipment the sidelink carrier aggregation configuration comprising the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier.
An apparatus, in certain embodiments, may include means for configuring at a network entity a sidelink carrier aggregation configuration comprising a timing offset. The apparatus may also include means for transmitting from the network entity to a user equipment the sidelink carrier aggregation configuration comprising the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier.
According to certain embodiments, a computer program product embodied in a non-transitory computer-readable medium and encoding instructions that, when executed in hardware, perform a process. The process may include configuring at a network entity a sidelink carrier aggregation configuration comprising a timing offset. The process may also include transmitting from the network entity to a user equipment the sidelink carrier aggregation configuration comprising the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier.
According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include configuring at a network entity a sidelink carrier aggregation configuration comprising a timing offset. The process may also include transmitting from the network entity to a user equipment the sidelink carrier aggregation configuration comprising the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier.

BRIEF DESCRIPTION OF THE DRAWINGS:

For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:
Figure 1 illustrates an LTE vehicle-to-everything resource allocation.
Figure 2 illustrates an example of a system according to certain embodiments.
Figure 3 illustrates an example of a signal flow diagram according to certain embodiments.
Figure 4 illustrates an example of a flow diagram according to certain embodiments.
Figure 5 illustrates an example of a flow diagram according to certain embodiments.
Figure 6 illustrates an example of system according to certain embodiments.

DETAILED DESCRIPTION:

Certain embodiments may allow for a network-configured SLCA timing offset (Tca) , to control SLCA transmissions of a transmitting user equipment (Tx UE) . The Tx UE may determine the timing offset between the SLCA transmissions, as well as related resource selection, based on a received network configuration. The SLCA may utilize a first carrier, which may be referred to as a PC5 carrier, and/or a second carrier, which may be referred to as another PC5 carrier. In some embodiments, the user equipment may use a mode 4 resource allocation in the second carrier, while the user equipment may use either mode 3 resource allocation or the mode 4 resource allocation in the first carrier.
As will be discussed below, certain embodiments help to distinguish SLCA from generic uncoordinated or autonomous SL transmissions on different carriers. Multi-carrier SL transmission may utilize a mode 4 Tx UE. Mode 4 resource allocation refers to a UE’s autonomous resource selection from the one or more configured resource pool. . In other embodiments, multi-carrier SL transmission may utilize mode 3 resource allocation, which refers to network scheduling based resource allocation.
Carrier aggregation, including dual connectivity (DC) , has been standardized for cellular links, such as a radio connection over a Uu interface between a UE and a serving radio access network (RAN) . The serving RAN may include a primary cell and a secondary cell. In an inter-site CA and DC, the primary cell and the secondary cell may be provided by two different enhanced NodeB (eNB) or access nodes (ANs) . Transmissions over the Uu interface may be connection oriented for certain EPC bearer services. CA and/or DC over the Uu interface may therefore be tightly controlled by a primary cell. The transmissions over SL, on the other hand, is based on Tx UE oriented broadcasting for per-packet equipment-to-equipment applications. Both network-scheduled and autonomous UE selected resource allocation modes, referred to as mode 3 and mode 4, may be supported for vehicle to everything transmission over a SL.
Some embodiments may help to facilitate network controlled SLCA in LTE Release 15, or any future LTE release. Certain embodiments focus on the UE using a mode 4 resource allocation in the second carrier. The UE, on the other hand, may use either a mode 3 resource allocation or a mode 4 resource allocation in the first carrier. While in traditional carrier aggregation over the Uu interface a primary cell and a secondary cell are used, in SLCA, for example, a first carrier and a second carrier may be used. The first and second carriers may be PC5 carriers.
Figure 1 illustrates an LTE vehicle-to-everything resource allocation. In particular, Figure 1 illustrates a timeline of LTE vehicle-to-everything PC5 based resource allocation mechanism for a transmitting UE using a mode 4 resource allocation. PC5 may be a device-to-device or vehicle-to-vehicle interface, also known as a sidelink connection in the physical layer. The detailed mechanism of sensing and semi-persistent scheduling (SPS) resource allocation, shown in Figure 1, includes a sliding sensing window. The sensing window dictates that the user equipment should continue to sense the transmissions from other UEs in each receiving subframe in sliding sensing window 110, which may have a duration of a 1000 milliseconds. The sliding sensing window in Figure 1 may range between n-1000 to n-1, with n being a point in time in which resource selection or reselection is triggered. If and when the resource selection or reselection is triggered 120, the UE may select the available resources in resource selection window 130, which may range from n+T1 to n+T2.
The upper edge of the resource selection window may be restricted by the current payload latency, and the lower edge of the resource selection window may be determined by the process delay based on the UE implementation. According to the occupancy state of the resources detected in sensing window 110, if and when the UE selects the available resources in the resource selection window at subframe (n+d) , the same frequency resource of (n+d+SPS period) will be reserved by the scheduling assignment transmitted in (n+d) . d may be the time period after the triggering of the resource selection or resection that it takes the UE to select or reselect the resource.
When resource selection or reselection is triggered, the SPS counter value may be uniformly randomly selected between the proposed ranges. The proposed ranges may be determined by the upper edge and the lower edge of the resource selection window. After each transmission of traffic packets, the value of the SPS counter may be decreased by a value of one. When the SPS counter meets the expiration condition, the current resources may have a probability p to be kept, and the SPS counter may be reset, or the reselection may be triggered with probability (1-p) .
Certain embodiments introduce a network-configured SLCA timing offset, also referred to as Tca hereinafter. The Tca may be used to control SLCA transmissions of a Tx UE, especially in those embodiments in which the UE uses a mode 4 resource allocation. The user equipment may determine whether to transmit data using the SLAC on resources of at least one of a first carrier or a second carrier. In particular, the user equipment may determine the timing between the transmissions of SLCA, as well as the related resource selection, signaling indication, and Layer 2 (L2) behaviors over SL according to configured Tca. The L2 comprises medium access control (MAC) , radio link control (RLC) , and/or packet data conversion protocol (PDCP) sub-layers. L2 behaviors may relate to moving data across the physical links in the network. Tca may be configured or pre-configured by the network or may be pre-defined by a network operator, for example. The Tca configuration may then be transmitted to the user equipment, as shown in Figure 2.
Figure 2 illustrates an example of a system according to certain embodiments. In particular, Figure 2 illustrates sidelink carrier aggregation that utilizes both a first carrier and a second carrier, as well as a method for controlling the selection of second carrier and mode 4 resource allocation on the second carrier in SLCA using Tca. As can be seen in Figure 2, the transmitting UE may be able to select between first carrier 210, referred to as carrier#1, and two different second carriers 220 and 230, referred to as carrier#2 and carrier#L. The UE may use a mode 3 resource allocation or a mode 4 resource allocation in the first carrier, while using the mode 4 resource allocation in the second carrier. In first carrier 210, the UE may transmit data on resource block 240. The UE may then proceed to transmit data on resource block 250 in second carrier 220. In certain embodiments, when the UE uses mode 4 on the first carrier, the first carrier may be selected by the UE among the selectable carriers pre-configured to the UE by the network.
Delta T in Figure 2, may represent a time offset between the transmission of data in resource block 240 in first carrier 210, and data in resource block 250 in second carrier 220. Delta T in Figure 2 may also be a time offset referred to as Tca. As shown in Figure 2, the value of delta T, meaning the Tca used by the Tx UE, may fall between a Tca minimum value (Tca_min) and a Tca maximum (Tca_max) value. The Tca may be pre-configured or pre-defined by a network entity or by an operator of the network. The timing offset may include a minimum value and a maximum value. In some embodiments, the Tca_min may be set to zero. The Tca, in certain embodiments, may be derived, set, or determined based on at least one of a quality of service (QoS) , SLCA operation, and/or mode 4 resource allocation operation used by the Tx UE in the second carrier.
As discussed above, Tca may include one or more pre-defined or pre-configured elements or components. For example, the Tca may include a minimum value, a maximum value, and/or a single norm, which may be a single number or value. In certain embodiments, the single norm may be implicitly considered by the UE, and up to the UE to derive, or explicitly configured to the UE as the Tca_max, while Tca_min is zero. In another instance, the single norm may be considered or configured as Tca_min, while Tca-max may be derived by the UE. The implicit option may be realized via the constraint or the actual value of this single norm. In other words, the UE may compare the value of the single norm to, for example, the delay requirement of the corresponding application or service, which may correspond to PPPP of packets, to determine if the single norm is meant for Tca_min or Tca_max.
The Tca may also include specific values for different instances corresponding to different target use cases. The different target use cases, for example, may be determined based on different proximity services (ProSe) per packet priority (PPPP) of the data and/or different QoS classes of SLCA. In certain embodiments, the Tca may be UE specific, which may be configured using dedicated signaling, and/or first carrier specific, which may be configured using either dedicated signaling or common signaling.
While some components of the Tca may be commonly configured, such as the Tca_max, some other components of Tca may be configured using dedicated signaling, such as Tca_min. Commonly configured may mean that the Tca component is configured for one or more UEs in a cell using, for example, broadcasting, while being configured using dedicated signaling may mean that each individual UE is configured using the dedicated signaling. In some other embodiments, some elements or components of the Tca may be implicitly configured. When the Tca is implicitly configured, the Tca may be derived from at least one of the SPS period of a corresponding SPS instance on first carriers. In yet another embodiment, the Tca may be derived based on a time interval between two successive SL hybrid automatic repeat request (HARQ) repetitions on the first carrier. The Tca may also be derived from the time constraint of the configured research selection window and/or a delay or latency corresponding to a PPPP or a QoS configuration. The Tca may be derived based on one or more of the above factors.
In certain embodiments, components or elements of the Tca, such as Tac_min or Tac_max, may not be explicitly configured by the network entity. The network entity, for example, may be an eNB. Where the components or elements of the Tca are not explicitly configured, the Tx UE may implicitly derive the components or elements, as described above. In other embodiments, however, the components may be pre-defined or pre-configured. For example, Tca_min may be set to zero ifnot otherwise explicitly configured. Tca_max may also have a pre-defined or pre-configured value.
Transmission of the data from the user equipment using the sidelink carrier aggregation on the second carrier may be caused to occur between the minimum value and the maximum value, counting from the time instance of the transmitting of the data on the first carrier. In some embodiments, therefore, the timing difference between two consecutive transmissions of SLCA on the first carrier and the second carrier may occur between Tca_min and Tca_max. In other words, two consecutive transmission time intervals (TTIs) of SLCA for corresponding SL resource block may be caused to occur between a Tca_min and a Tca_max. This may allow for controlling network resource usage, while also providing the required data rate, for example, when the Tx UE uses mode 4 resource allocation for SLCA.
In certain embodiments, in which the SCLA may be used for duplication a critical packet that may require high reliability and low latency, the Tca_max may be set according to the time interval between two successive SL HARQ repetitions on the first carrier. In other embodiments, the Tca_max may be set according to the required latency and/or delay of corresponding PPPP or QoS configuration. Deriving or setting the Tca_max in accordance with the above may help to ensure effectiveness of the SLCA over single carrier transmission.
Tx UE may be configured to select, in some embodiments, a second carrier and a resource on the second carrier that minimizes a timing difference between two consecutive transmission time intervals of the SLCA on the first carrier and the second carrier, when the SLCA is used for a split of data. In other embodiments, a Tx UE may be configured to select a second carrier and a resource on the second carrier that maximizes a timing difference between two consecutive time intervals of the SLCA on the first carrier and the second carrier, when the SLCA is used for duplication of data. Configuring the Tx UE in accordance with the above may boost the data rate in case of split, or boost the time diversity in case of duplication.
In other embodiments, the Tca_max as shown in Figure 2 may be smaller than the time constraint of the configured resource selection window on second carrier. The Tx UE may select resources on second carrier before or after sending a scheduling assignment for transmitting of the data on the first carrier. In certain embodiments, whether the resources of the second carrier are selected before or after sending the scheduling assignment for transmitting of the data on the first carrier, the determined resources for transmission may depend on the timing offset and a pre-configured resource selection time window of the second carrier. The time constraint may refer to the time duration the UE may need to perform the sensing and/or the resource selection, as illustrated in Figure 1.
The sensing and/or the resource selection may be performed by taking into account that the timing of the trigger for selecting resources on second carrier, for example the n slot in Figure 1, which may be tied to the timing of the SLCA transmission determined and scheduled on first carrier, referred to below as n_first carrier. The n parameter of the first carrier may represent the n-th time slot of the first carrier on which SLCA may be triggered. For example, ifthe Tca_max or if the (Tca_max+Tca_min) /2 is smaller than first carrier’s n+T2, Tx UE may select resources on second carrier before sending a scheduling assignment on the first carrier. T2 may be a configured parameter specific to the second carrier. The first carrier’s n+T2, therefore, may represent the end of the resource selection window, similar to the resource selection window shown in Figure 1. The above embodiment may apply when the Tca_max is smaller than the n of the first carrier + T1 of the second carrier.
The scheduling assignment for SLCA, in some embodiments, may be sent on the first carrier. The scheduling assignment may include indications about the SLCA, such as whether the SLCA may be used for split transmission or duplicate transmission. The scheduling assignment indicating the SLCA may need to provide explicit resources used for SLCA on the second carrier. This may help to enhance sensing and/or avoiding a collision on the second carrier. Ifthe Tca_max is larger than n first carrier+T2, then the scheduling assignment sent on first carrier may skip indicating about the SLCA.
Figure 3 illustrates an example of a signal flow diagram according to certain embodiments. In particular, Figure 3 illustrates a network entity 301, for example an eNB, and a Tx UE 302 that utilizes SLCA. In certain embodiments, a network entity configures a sidelink carrier aggregation configuration including a timing offset. In step 310, the network entity transmits to a user equipment the SLAC configuration including the timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier. In other words, in step 310, Tx UE 302 may receive a SLAC configuration, that includes a timing offset.
In step 320, the Tx UE 302 may determine SLCA transmissions and resources of first carrier for SLCA. In step 330, the Tx UE 302 may determine whether to transmit on the first carrier resources for SLCA, before determining second carrier resources or not based on the configured Tca. In other words, in step 330 Tx UE 302 may determine whether the Tx UE has enough time to transmit data on the first carrier, select the second carrier’s resource, and transmit data on the second carrier for the sidelink carrier aggregation. In certain embodiments, the Tx UE does not have enough time and needs to select the second carrier’s resource before transmitting data on the first carrier. The determination may be based on the Tca. When the Tx UE determines to transmit on the first carrier resources for SLCA before determining the second carrier resources, referred to as “Yes” in Figure 3, the UE may perform the SLCA transmission of the first carrier with scheduling assignment indicating the first carrier resources, as shown in step 340. In other words, Tx UE 302 transmits data using the SLCA on the resources of the first carrier. The “Yes” decision in Figure 3 may be based on the Tca minimum being larger than the earliest selectable resources on a selectable second carrier for instance.
First carrier for the SLCA may be the controlling cell when the Tx UE uses mode 3 or a mix of a mode 3 and mode 4 resource allocation. When Tx UE uses the mode 4 resource allocation, the UE may select to transmit in the first carrier in SLCA. The other carrier may be a second carrier. In certain embodiments, the minimum Tca may be set to zero. The UE capabilities, such as the transmitting or receiving antennas of the UE, may be taken into account when configuring the Tca. Tca may therefore help to resolve UE capability limitations.
If Tx UE 302 determines to transmit the first carrier resources for SLCA without first determining second carrier resources, referred to as “No” in Figure 3, the UE may perform SLCA transmission on first carrier with a scheduling assignment indicating first carrier resources, and optionally second carrier resources, as shown in step 360. In step 350, Tx UE 302 may determine, among selectable second carriers, a suitable second carrier, and resources of second carrier for SLCA based on the configured Tca. In step 330, Tx UE 302 may determine whether to transmit data using the sidelink carrier aggregation on resources of a second carrier. In step 370, the UE may perform SLCA Tx on second carrier with a scheduling assignment indicating second carrier resources.
Figure 4 illustrates a flow diagram according to certain embodiments. Specifically, Figure 4 illustrates an embodiment of a Tx UE, which may be used in a vehicle-to-everything communication. Tx UE, for example, may be Tx UE 302 shown in Figure 3. In step 410, the Tx UE may receive a SLCA configuration, wherein the SLCA configuration comprises a timing offset, similar to step 310 as shown in Figure 3. In step 420, the Tx UE may determine to transmit data using the SLCA on a resource of a first carrier and a resource of a second carrier based, for example, on the timing offset and a timing of the resource of the first carrier, as shown in steps 330 and 350 of Figure 3. The Tx UE may select the second carrier from a plurality of second carriers, as shown in Figure 2. The user equipment may use a mode 4 resource allocation in the second carrier, while the user equipment may use a mode 3 resource allocation or the mode 4 resource allocation in the first carrier. The timing offset may be pre-configured by a network entity.
In certain embodiments, the timing offset may include a minimum value and a maximum value. The transmitting of the data from the user equipment using the SLCA on the second carrier may occur between the minimum value or the maximum value, counting from the time instance of the transmitting of the data on the first carrier. In some embodiments, the timing offset may be derived based on at least one of a time interval between two successive SL HARQ repetitions on the first carrier or a latency corresponding to a per packet profity of a data or a QoS configuration.
The UE may select the resources on the second carrier before or after sending a scheduling assignment for the first carrier, depending on the timing offset and/or a preconfigured resource selection time window of the second carrier. The UE may select the resource on the second carrier that minimizes or maximizes a timing difference between two consecutive TTIs of the SLCA on the first carrier and the second carrier. As shown in step 430, the UE may indicate a scheduling assignment for the resource of at least one of the first carrier or the second carrier. In step 440, the user equipment may transmit data using SLCA on the resource of the first carrier and the resource of the second carrier. The SLCA may be used in a vehicle-to-everything communication, for example a vehicle-to-vehicle communication.
Figure 5 illustrates a flow diagram according to certain embodiments. Specifically, Figure 5 illustrates an embodiment of a network entity, such as an eNB, similar to the eNB 301 in Figure 3. The network entity shown in Figure 5 may communicate with the user equipment shown in Figure 4. In step 510, the network entity configures a SLCA configuration comprising a timing offset. The timing offset may include a minimum value and a maximum value. The timing offset may be derived based on at least one of a time interval between SL HARQ repetitions on the first carrier or a latency corresponding to per packet priority of the data or QoS configuration. In step 520, the network entity may transmit to a user equipment a SLCA configuration comprising a timing offset. The timing offset may relate to transmissions of data using a resource of a first carrier and a resource of a second carrier. The UE may use a mode 4 resource allocation in the second carrier, and the user equipment may use a mode 3 resource allocation or the mode 4 resource allocation in the first carrier.
Figure 6 illustrates a system according to certain embodiments. It should be understood that each signal or block in Figures 1, 2, 3, 4, and 5, may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, a network entity 620 or a user equipment 610. The system may include more than one UE 610 and more one network node 620, although only one access node shown for the purposes of illustration. The network entity may be a network node, an access node, a base station, an eNB, a 5G NodeB (5G-NB) , server, host, or any of the other access or network node discussed herein.
Each of these devices may include at least one processor or control unit or module, respectively indicated as 611 and 621. At least one memory may be provided in each device, and indicated as 612 and 622, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceiver 613 and 623 may be provided, and each device may also include an antenna, respectively illustrated as 614 and 624. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. Higher category UEs generally include multiple antenna panels. Other configurations of these devices, for example, may be provided. For example, network node 620 and UE 610 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 614 and 624 may illustrate any form of communication hardware, without being limited to merely an antenna.
Transceivers 613 and 623 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. In other embodiments, the UEs or the network node may have at least one separate receiver or transmitter. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. The operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One possible use is to make a network node deliver local content. One or more functionalities may also be implemented as virtual application (s) in software that can run on a server.
A user device or user equipment 610 may be a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof. User equipment 610 may utilize an LTE mode 4 resource allocation or an LTE mode 3 resource allocation. User equipment 610 may be used in a vehicle-to-everything communication. Therefore, user equipment 610 may be located inside or may be part of a vehicle.
In some embodiments, an apparatus, such as a network entity, may include means for carrying out embodiments described above in relation to Figures 1, 2, 3, 4, and 5. In certain embodiments, at least one memory including computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform any of the processes described herein.
Processors 611 and 621 may be embodied by any computational or data processing device, such as a central processing unit (CPU) , digital signal processor (DSP) , application specific integrated circuit (ASIC) , programmable logic devices (PLDs) , field programmable gate arrays (FPGAs) , digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors.
For firmware or software, the implementation may include modules or unit of at least one chip set (for example, procedures, functions, and so on) . Memories 612 and 622 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD) , random access memory (RAM) , flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.
The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as network entity 620 or UE 610, to perform any of the processes described above (see, for example, Figures 1, 2, 3, 4, and 5) . Therefore, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments may be performed entirely in hardware.
Furthermore, although Figure 6 illustrates a system including a network entity 620 and UE 610, certain embodiments may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network entities may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and an network entity, such as a relay node. The UE 610 may likewise be provided with a variety of configurations for communication other than communication network node 620. For example, the UE 610 may be configured for device-to-device, machine-to-machine, vehicle-to-everything, or vehicle-to-vehicle communication.
The above embodiments may provide for significant improvements to the functioning of a network and/or to the functioning of the network entities within the network. Specifically, certain embodiments allow for effective and efficient network-controlled SLCA transmissions by a Tx UE. In one example, the Tx UE may be involved as part of a vehicle-to-everything communication, such as direct vehicle-to-vehicle communication. A network configured timing offset may be used to determine the timing between the transmissions of SLCA, as well as related resource selection in a first carrier and a second carrier.
The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases “certain embodiments, ” “some embodiments, ” “other embodiments, ” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearance of the phrases “in certain embodiments, ” “in some embodiments, ” “in other embodiments, ” or other similar language, throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention.
Partial Glossary
3GPP Third Generation Partnership Project
LTE Long Term Evolution
LTE-A Long Term Evolution Advanced
CA Carrier Aggregation
SA Scheduling Assignment
SL Sidelink
SLCA Sidelink CA
TTI Transmission Time Interval
V2V Vehicle-to-Vehicle communication
MAC Medium Access Control
RAN Radio Access Network
eNB evolved NodeB
SPS Semi-Persistent Scheduling
PPPP Proximity Services Per Packet Priority
HARQ Hybrid Automatic Repeat Request
Tca SLCA Timing Offset

Claims

A method comprising:

receiving at a user equipment a sidelink carrier aggregation configuration, wherein the sidelink carrier aggregation configuration comprises a timing offset;

determining to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier; and

transmitting data from the user equipment using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
The method according to claim 1, wherein the user equipment uses a mode 4 resource allocation in the second carrier, and wherein the user equipment uses either a mode 3 resource allocation or the mode 4 resource allocation in the first carrier.
The method according to claim 1, wherein the timing offset is pre-configured by a network entity.
The method according to claim 1, wherein the timing offset comprises a minimum value and a maximum value, and wherein the transmitting of the data from the user equipment using the sidelink carrier aggregation on the second carrier occurs between the minimum value and the maximum value, counting from a time instance of the transmitting of the data on the first carrier.
The method according to claim 1, wherein the timing offset is derived based on at least one of a time interval between two successive sidelink hybrid automatic repeat request repetitions on the first carrier or a latency corresponding to a per-packet priority of the data or a quality of service configuration.
The method according to claim 1, further comprising:

selecting at the user equipment the resource on the second carrier before or after sending a scheduling assignment for the transmitting of the data on the first carrier depending on the timing offset and preconfigured resource selection time window of the second carrier.
The method according to claim 1, further comprising:

selecting at the user equipment the resource on the second carrier that minimizes or maximizes a timing difference between two consecutive transmission time intervals of the sidelink carrier aggregation on the first carrier and the second carrier.
The method according to claim 1, further comprising:

indicating a scheduling assignment for the resource of at least one of the first carrier or the second carrier.
The method according to claim 1, wherein the sidelink carrier aggregation configuration is used in a vehicle-to-everything communication.
The method according to claim 1, further comprising:

selecting the second carrier from a plurality of second carriers.
A method comprising:

configuring at a network entity a sidelink cartier aggregation configuration comprising a timing offset; and

transmitting from the network entity to a user equipment the sidelink cartier aggregation configuration comprising the timing offset, wherein the timing offset relates to transmissions of data using a resource of a first carrier and a resource of a second carrier.
The method according to claim 11, wherein the user equipment uses a mode 4 resource allocation in the second carrier, and wherein the user equipment uses a mode 3 resource allocation or the mode 4 resource allocation in the first carrier.
The method according to claim 11, wherein the timing offset comprises a minimum value and a maximum value.
The method according to claim 11, wherein the timing offset is derived based on at least one of a time interval between two successive sidelink hybrid automatic repeat request repetitions on the first carrier or a latency corresponding to a per-packet priority of the data or a quality of service configuration.
An apparatus comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform a process, the process comprising:

receive a sidelink carrier aggregation configuration, wherein the sidelink carrier aggregation configuration comprises a timing offset;

determine to transmit data using a sidelink carrier aggregation on a resource of a first carrier and a resource of a second carrier based on the timing offset and a timing of the resource of the first carrier; and

transmit data using the sidelink carrier aggregation on the resource of the first carrier and the resource of the second carrier.
The apparatus according to claim 15, wherein the user equipment uses a mode 4 resource allocation in the second carrier, and wherein the user equipment uses a mode 3 resource allocation or the mode 4 resource allocation in the first carrier.
The apparatus according to claim 15, wherein the timing offset is pre-configured by a network entity.
The apparatus according to claim 15, wherein the timing offset comprises a minimum value and a maximum value, and wherein the transmitting of the data from the user equipment using the sidelink carrier aggregation on the second carrier occurs between the minimum value and the maximum value, counting from a time instance of the transmitting of the data on the first carrier.
The apparatus according to claim 15, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform a process, the process further comprising:

indicating a scheduling assignment for the resources of at least one of the first carrier or the second carrier.
An apparatus comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform a process, the process comprising:

configure a sidelink carrier aggregation configuration comprising a timing offset; and

transmit to a user equipment the sidelink carrier aggregation configuration comprising the timing offset, wherein the timing offset relates to transmissions of data using carrier resource of a first carrier and a resource of a second carrier.
An apparatus comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform a process, the process including the method according to any of claims 5-7, 9, 10, and 12-14.
A non-transitory computer-readable medium encoding instructions that, when executed in hardware, perform a process, the process including the method according to any of claims 1-14.
An apparatus comprising means for performing a process, the process including the method according to any of claims 1-14.
A computer program product encoding instructions for performing a process, the process including the method according to any of claims 1-14.
A computer program product embodied in a non-transitory computer-readable medium and encoding instructions that, when executed in hardware, perform a process, the process including the method according to any of claims 1-14.